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  • Ultrastructure  (74)
  • paleolimnology  (54)
  • Biomagnetism (including magnetocardiography)  (46)
  • superconducting magnets  (46)
  • Springer  (175)
  • 1980-1984  (175)
  • 1925-1929
  • 1983  (175)
Collection
Keywords
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  • Springer  (175)
Years
  • 1980-1984  (175)
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Instrumentation for biomagnetism (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 123-141 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riesamina la strumentalizzazione adatta all’acquisizione di segnali biomagnetici. Si studiano separatamente i componenti di base del magnetometro, cioè gli SQUID, i trasformatori di flusso e i dewar. Si discutono i possibili miglioramenti alla strumentazione attuale e alle apparecchiature complete comprendenti scudi ferromagnetici o di correnti a vortice e si valuta la loro efficenza.
    Notes: Summary The instrumentation suitable for the acquisition of biomagnetic signals is reviewed. The basic magnetometer components,i.e. SQUIDs, flux transformers and dewars, are studied separately. Possible improvements to the present instrumentation as well as complete set-ups including ferromagnetic or eddy current shields are discussed and their efficiency evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455917
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  • 2
    Electronic Resource
    Electronic Resource
    First-gradient balancing of higher-order gradiometers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 142-152 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si sviluppa un formalismo per la descrizione vettoriale e tensoriale di una procedura di bilanciamento e si sottolinea un metodo di bilanciamento di campo e di primo gradiente. Si discutono l’apparecchiatura sperimentale e le misurazioni del vettore di modo comune del primo gradienteC G 1.
    Notes: Summary A formalism for the vector and tensor description of a balancing procedure is developed and a first-gradient and field-balancing method is outlined. The experimental apparatus and measurements of the first-gradient common-mode vector,C G 1, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455918
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 4
    Electronic Resource
    Electronic Resource
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848687
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  • 5
    Electronic Resource
    Electronic Resource
    Optimization of the second-order gradiometer base length that has been designed for the measurement of weak inhomogeneous magnetic fields (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 175-183 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si tratta il problema dell’ottimizzazione di sistemi di sensori gradiometrici metrici superconduttori di secondo ordine che sono stati progettati per la misurazione di campi magnetici deboli disomogenei in un ambiente disturbato magneticamente. Si considerano le condizioni di massimo rapporto segnale-rumore dell’uscita del quantomagnetometro superconduttote (SQM). Si analizza l’influenza dei parametri misurati della sorgente del segnale, del rumore di una sorgente di disturbo esterna e di quello proprio del magnetometro sulla selezione della lunghezza di base del gradiometro.
    Notes: Summary In this paper we deal with an optimization problem of the second-order superconducting gradiometric sensor systems that have been designed for measurement of the weak inhomogeneous magnetic fields in a magnetically disturbed environment. The conditions of maximum signalto-noise ratio of the output of superconducting quantum magnetometers (SQM) are considered. The influence of measured signal source parameters, of an outside disturbing source and of the own noise of the magnetometer on the gradiometer base length selection is analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455921
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  • 6
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    Electronic Resource
    Optimizing vector magnetocardiographic lead fields by using a physical torso model (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 356-367 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono state esaminate l’idealità e la sensibilità di parecchi conduttori magnetocardiografici vettoriali usando un modello inomogeneo fisico del tronco. Si è trovato che la componente antero-posterioreX vettore magnetico del cuore è la piú facile da scoprire. Si suggeriscono conduttori ideali per le altre due componenti. Comunque questi hanno una sensibilità inferiore. Le differenze rispetto ai risultati di precedenti ricercatori sono state spiegate con le differenze tra i modelli.
    Notes: Summary The ideality and sensitivity of several vector magnetocardiographic leads were tested by using an inhomogeneous, physical torso model. The postero-anterior component of the heart’s magnetic vector was found easiest to detect. New, more ideal leads for the other two components are suggested. However, these have lower sensitivity. The differences from the results of former investigators can be explained by the differences of the models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455938
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  • 7
    Electronic Resource
    Electronic Resource
    Adaptive noise cancellation in neuromagnetic measurement systems (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 203-213 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato lo spettro del rumore di un gradiometro superconduttore a derivata secon da in un agglomerato urbano. I dati sono stati ottenuti dal gradiometro con tre accelerometri ortogonali e un magnetometro a flussometro elettronico triassiale attaccato al dewar. Questi dati sono stati analizzati usando tecniche di elaborazione dei segnali, soprattutto un cancellatore adattativo di rumori, per ridurre i rumori nei dati del gradiometro. I risultati mostrano qui che il rumore dell’esterno e/o il rumore del movimento del dewar possono essere ridotti di 40 dB in potenza di rumore. Si è anche mostrato che, nel caso di basso rapporto segnale-rumore (S/N∼1), può essere estratta un’onda sunusoidale di 10 Hz. Questa tecnica non solo promette riduzione dei rumori, ma ha anche lo scopo d’identificare i segnali di rumore che potrebbero essere veramente considerati parte del responso evocato. L’analisi dei dati che contengono i responsi evocati è ora in corso.
    Notes: Summary The noise spectrum of a superconducting second-derivative gradiometer has been investigated in an urban environment. Data have been acquired from the gradiometer with three orthogonal accelerometers and a triaxial fluxgate magnetometer attached to the dewar. These data have been analyzed by using signal processing techniques, primarily an adaptive noise canceller, to reduce noise in the gradiometer data. Results shown here indicate that the environmental noise and/or the dewar motion noise can be reduced as much as 40 dB in noise power. It is also shown, in the case of poor signal-to-noise ratio (S/N∼1), that a 10 Hz sine wave can be extracted. This technique not only shows promise for noise reduction, but also aids in the identification of noise signals which might be misconstrued as part of the evoked response. Analysis of data containing evoked response is now underway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455924
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  • 8
    Electronic Resource
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    Magnetic sensors with good signal-to-interference discrimination (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 153-165 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si stabiliscono princípi per il progetto di sistemi di spire che generano campi magnetici distanti che diminuiscono secondo una potenza inversa alta della distanza. Secondo un principio di reciprocità queste disposizioni, quando usate come sensori in magnetometri ad induzione e SQUID, hanno una sensibilità intrinsecamento bassa per sorgenti distanti del campo magnetico.
    Notes: Summary Principles are established for the design of coil arrays which generate distant magnetic fields diminishing as a high inverse power of the distance. By a principle of reciprocity these arrays, when used as sensors in induction and SQUID magnetometers, have an inherently low sensitivity to distant sources of magnetic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455919
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  • 9
    Electronic Resource
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    Measurement of biomagnetic fields using multichannel superconducting-magnetometer techniques (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 166-174 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito un magnetometro SQUID differenziale a 3 canali per la misurazione simultanea delle 3 componenti ortogonali del campo magnetico nella stessa posizione. Si descrive la struttura dell’apparecchio e si mostrano i dati MCG misurati. Si discutono gli effetti d’interferenza tra i canali.
    Notes: Summary We have constructed a three-channel differential SQUID magnetometer for the simultaneous measurement of the three orthogonal components of the magnetic field in the same location. The structure of the device is described and MCG data measured are shown. Interference effects between the channels are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455920
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  • 10
    Electronic Resource
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    Neuromagnetic measurements at hospital: Instrumentation and preliminary tests (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 184-194 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito espressamente un sistema SQUID in un ospedale di Parigi, che permette indagini neuromagnetiche attinenti con applicazioni cliniche. Un gradiometro simmetrico di second’ordine lavora entro uno schermo per corrente parassite. Ciò è designato ad ottimizzare il costo e l’efficienza del sistema. Le sue prestazioni sono state sperimentate con dati da pazienti e da soggetti normali.
    Notes: Summary A SQUID system was specially built in a Parisian hospital, allowing neuromagnetic investigations dealing with clinical applications. A second-order symmetrical gradiometer works inside an eddy current shield. This was designed for optimizing the cost and the efficiency of the system. Its performances were tested with data from patients and normal subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455922
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  • 11
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    A portable biomagnetic measuring system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 224-230 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si descrive la strumentazione per le applicazioni biomagnetiche. Le piccole dimensioni e la leggerezza del gradiometro SQUID permettono il facile trasporto e posizionamento dello strumento, rendendo cosí possibile le misurazioni biomagnetiche in una qualsiasi locazione in cui non ci siano rumori. L’apparecchio è provvisto di un alimentatore a batteria e, se riempito con 60 cm3 di elio liquido, funzionerà initerrottamente per 6 ore. L’apparecchio è adatto per la magnetocardiografia.
    Notes: Summary The instrumentation for biomagnetic applications is described. The small size and weight of the SQUID gradiometer permit easy transport and positioning of the instrument, thus making biomagnetic measurements possible in any noise-free location. The equipment is provided with a battery power supply, and, when filled with 60 cm3 of liquid helium, will operate continuously for 6 h. The device is suitable for magnetocardiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455926
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  • 12
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    Comparison between measured and simulated magnetocardiograms in a case of anterolateral myocardial infarction (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 301-310 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si confrontano i magnetocardiogrammi misurati in un caso di infarto miocardico anterolaterale con i corrispondenti magnetocardiogrammi simulati. I cambiamenti piú notevoli nell’MCG misurato si sono osservati nelle parti superiori e inferiori del torace come previsto dalla simulazione.
    Notes: Summary The MCGs measured in a case of an anterolateral myocardial infarction were compared with the corresponding simulated MCGs. The most distinctive changes in the measured MCGs were observed in the upper and lower parts of the thorax as predicted by the simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455933
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  • 13
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    Determination of the spatial distribution of abnormal EEG and MEG from current dipole in inhomogeneous volume conductor (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 558-566 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La conduttività elettrica delle lesioni cerebrali varia con situazioni patologiche come l’edema e la calcificazione. È stato studiato mediante una simulazione con il computer l’effetto delle disomogeneità dei tessuti delle lesioni cerebrali sulle distribuzioni spaziali dei potenziali elettrici e dei campi magnetici sulla superficie del capo.
    Notes: Summary The electrical conductivity of brain lesions varies with pathological situations such as edema and calcification. The effect of the tissue inhomogeneities of brain lesions on spatial distributions of electrical potentials and magnetic fields over the surface of the head was studied by means of a computer simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455954
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  • 14
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    Diagnostic assessment of human iron stores by measurement of hepatic magnetic susceptibility (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 567-581 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è sviluppato un metodo magnetico per misurazioni dirette non invasive del ferro di immagazzinamento epatico umano con uno suscettometro SQUID. Le determinazioni magneticain vivo e chimicain vitro del ferro epatico non eme sono strettamente correlate. Le misurazioni magnetiche dei depositi di ferro sono utili, dal punto di vista clinico, nella diagnosi dei disordini nel metabolismo del ferro.
    Notes: Summary A magnetic method for direct noninvasive measurements of human hepatic storage iron with a SQUID susceptometer has been developed.In vivo magnetic andin vitro chemical determinations of liver nonheme iron are closely correlated. Magnetic measurements of iron stores are clinically useful in the diagnosis of disorders of iron metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455955
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  • 15
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    The inverse problem in magnetopneumography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 594-607 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il problema inverso nella misurazione magnetical del polmone è stato studiato con un metodo che usa le ipotetiche distribuzioni del pulviscolo magnetico. Si sono fatte le minimizzazioni non vincolate e vincolate di una funzione obiettiva. Le simulazioni e l’analisi hanno mostrato l’efficacia del metodo.
    Notes: Summary The inverse problem in the magnetic measurement of the lung was studied with a method using hypothetical distributions of magnetic dust. Both unconstrained and constrained minimizations of an objective function were performed. Simulations and analysis showed the efficacy of the method.
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    URL: http://dx.doi.org/10.1007/BF02455957
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  • 16
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    A clinical system for accurate assessment of tissue iron concentration (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 582-593 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Questo lavoro descrive un nuovo suscettometro SQUID a doppio canale coadiuvato da computer destinato a raggiungere stime accuratein vivo delle concentrazioni di accumulo di ferro nei tessuti. Si discutono le considerazioni pratiche dello schema, la funzionalità sperimentale al rumore e la risoluzione clinica anticipata del nuovo sistema.
    Notes: Summary This paper describes a new computer-enhanced dual-channel SQUID susceptometer designed to achieve accuratein vivo estimates of tissue storage iron concentrations. We discuss the practical design considerations, instrumental noise performance and anticipated clinical resolution of the new system.
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    URL: http://dx.doi.org/10.1007/BF02455956
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  • 17
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    Magnetopneumography in welders: Observations on relaxation and clearance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 608-616 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è trovato che la velocità di decadimento del campo residuo ottenuto tramite magnetizzazione delle particelle ferromagnetiche trattenute nei polmoni dei saldatori è associato a fattori come la quantità di polvere trattenuta, il curriculum lavorativo e la consuetudine di fumare. Una velocità di decadimento piú rapida appare correlata con un piú rapido smaltimento delle particelle di fumo di saldatura nei fumatori.
    Notes: Summary It was found that the rate of decay of the remanent field obtained through magnetization of ferrimagnetic particles retained in the lungs of are welders is associated with factors such as amount of dust retained, occupational history and smoking habits. A faster decay rate was found to correlate with a faster clearance of welding fume particles in smokers
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    URL: http://dx.doi.org/10.1007/BF02455958
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  • 18
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    Magnetic particles in the lung: A probe for alveolar macrophage function (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 617-623 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Particelle ferromagnetiche immesse per via intratracheale nei polmoni sono fagocitate da macrofagi alveolari. Dopo che queste particelle sono state magnetizzate dal campo esterno, esse producono un campo residuo che decade rapidamente a causa del disallineamento delle particelle dovuto al movimento citoplasmatico (rilassamento). I cambiamenti nel valore di rilassamento nel tempo successivo all’immissione potrebbero essere connessi alla mobilità citoplasmatica.
    Notes: Summary Ferrimagnetic particles instilled intratracheally into the lungs are phagocytized by alveolar macrophages. After these particles are magnetized by an external field, they produce a remanent field which decays rapidly due to particle misalignment from cytoplasmic motion (relaxation). Changes in relaxation rate with time following instillation might be related to cytoplasmic motility.
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    URL: http://dx.doi.org/10.1007/BF02455959
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  • 19
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    Magnetic-susceptibility plethysmography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 624-641 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La pletismografia a suscettività magnetica (MSPG) è un nuovo metodo proposto per controllare i cambiamenti del volume cardiaco. Si riesaminano il principio di misurazione e i lavori recenti di altri ricercatori. Si studia l’effetto del movimento legato al cuore della cassa toracica anteriore sul segnale MSPG.I risultati suggeriscono che il movimento del confine cassa toracica-aria può contribuire in modo significativo (∼75%) al segnale MSPG quando è registrato vicino al cuore.
    Notes: Summary Magnetic-susceptibility plethysmography (MSPG) is a new method proposed for monitoring cardiac-volume changes. The measurement principle and recent work by other investigators are reviewed. The effect of the cardiac-related motion of the anterior chest wall on the MSPG signal is studied. The results suggest that the motion of the chest-wall-air boundary may contribute significantly (∼75%) to the MSPG signal when recorded near the heart.
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    URL: http://dx.doi.org/10.1007/BF02455960
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  • 20
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    Magnetic signals from human skeletal muscles (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 642-649 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata esaminata la forma d’onda d’impulso per il magnetomiogramma (MMG) dell’arto inferiore destro umano. Le durate tipiche degl’impulsi sono di circa (10÷20) ms. La variazione spaziale del MMG suggerisce un’origine nei muscoli anteriori della tibia.
    Notes: Summary The pulse wave form for the magnetomyogram (MMG) of the human right leg was examined. The typical pulse durations are about (10÷20) ms. The spatial variation of the MMG suggests a source in the anterior muscles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455961
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    d.c. Magnetic fields of the human leg as a function of position and relaxation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 650-659 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le ricerche sul campo magnetico intorno alla gamba umana con l’uso di un magnetometro SQUID producono risultati consistenti e riproducibili che possono essere rappresentati mediamente due linee di corrente, orientate inversamente, parallele all’asse della gamba. I campi sono condizionati dall’attività muscolare, che decade col tempo di rilassamento della gamba.
    Notes: Summary Investigations of the magnetic field around the human leg using a SQUID magnetometer yield consistent, reproducible results which can be modelled by 2 oppositely oriented line currents parallel to the leg axis. The fields are affected by muscle activity, decaying with the time of relaxation of the leg.
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    URL: http://dx.doi.org/10.1007/BF02455962
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    High-resolution recordings of the magnetic activity of the His-Bundle in man (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 1110-1118 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto L'attività del sistema di His-Purkinje è stata misurata magneticamente usando un magnetometro SQUID nella camera schermata magneticamente di Berlino (BMSR) e usando in aggiunta filtraggio (banda passante da 0.5 Hz a 300 Hz) e tecniche di mediazione. La camera riduce il livello di rumore di fondo a meno di 4 $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ nella regione a spettro bianco. All'interno dell'intervalloPR è stata osservata una struttura a rampa, la cui pendenza cambia segno attraversando la linea mediana del cuore. In aggiunta, sono stati registrati segnali ben definiti approssimativemente 40 ms prima dell'inizio dell'attivazione ventricolare.
    Abstract: Резюме йзмеряется активность НР системы у человека с помощью SQUID магнетометра в Берлинской магнитно экранированной комнате, используя фильтртрацию полосы пропускания (ширина полосы от 0.5 Гц до 300 Гц) и усреднение. Берлинская магнитно экранированная комната уменьшает уровень фонового шума до величины $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ в области белого шума. ВнутриPR интервла наблюдается диаграмма с уклоном, причем величина ыклона меняется при пересечении медианной линии сердца. Кроме того, ориблизительно за 40 мс до наступления активности желудочка регистрируются определенные сигналы.
    Notes: Summary The activity of the His-Purkinje system (HPS) in man has been measured magnetically with a SQUID magnetometer in the Berlin magnetically shielded room (BMSR) by using in addition band pass filtering (band width 0.5 Hz to 300 Hz) and averaging. The BMSR reduces the background noise level to less than $$4{{fT} \mathord{\left/ {\vphantom {{fT} {\sqrt {Hz} }}} \right. \kern-\nulldelimiterspace} {\sqrt {Hz} }}$$ in the region of white noise. Within thePR interval a ramp pattern was observed, changing its slope when crossing the median line of the heart. In addition, definite signals were recorded approximately 40 ms before the onset of ventricular activation.
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    URL: http://dx.doi.org/10.1007/BF02457146
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    An eddy-current-shielded room with a partially closed entrance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 195-202 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si mostra che miglioramenti sostanziali possono essere ottenuti nelle proprietà di schermatura di una stanza schermata da corrente parassite coprendo l’accesso con lamine conduttrici. I risultati suggeriscono che non è necessario installare una porta conduttrice e mostrano che è il caso di coprire una piccola parte della porta in modo permanente.
    Notes: Summary We show that substantial improvements can be obtained in the shielding properties of an eddy-current-shielded room by covering the doorway with conductive plates. Results suggest that it is unnecessary to install a conductive door and show that it is worthwhile covering a small part of the doorway permanently.
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    URL: http://dx.doi.org/10.1007/BF02455923
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    High-resolution recordings of thePR segment in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 248-254 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione è stato registrato mediante magnetometri superconduttori in 12 volontari sani utilizzando la camera schermata di Berlino per ridurre il livello di rumore elettromagnetico. La morfologia del trattoPR magnetico è caratterizzata dalle «rampe» in precedenza osservate, sulle quali s’inseriscono segnali. A volte la forma d’onda appare complessa.
    Notes: Summary ThePR interval of magnetocardiograms has been measured with a SQUID sensor in the Berlin magnetically shielded room. In addition to previously reported ramps with isolated superimposed signals in several cases a structured morphology has been found.
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    URL: http://dx.doi.org/10.1007/BF02455928
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    Atrial activity during thePR segment of the MCG (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 266-279 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati osservati segnali degradanti nel segmentoPR dei magnetocardiogrammi normali registrati da 5 cani. Sono state osservate rampe maggiori dopo aver indotto con farmaci il blocco del nodo atrioventricolare di primo grado, ed è stata osservata una completa ripolarizzazione atriale a seguito d’isolate contrazioni atriali in due animali con blocco di secondo grado. Queste rampe, che variano fino a 6.7 pT in ampiezza e provengono dagli atri, possono complicare l’individuazione magnetica dell’attività di His-Purkinje.
    Notes: Summary Sloping signals were observed in thePR segment of normal magnetocardiograms recorded from five dogs. Larger ramps were observed after first-degree AV nodal blockade was induced pharmacologically, and complete atrial repolarization was observed following isolated atrial contractions in two animals with second-degree block. These ramps, ranging up to 6.7 pT in size and arising from the atria, may complicate magnetic detection of His-Purkinje activity.
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    URL: http://dx.doi.org/10.1007/BF02455930
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    High-resolution magnetic measurements of human cardiac electrophysiological events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 231-247 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La motivazione fondamentale per lo studio dei fenomeni elettrofisiologici cardiaci tramite il metodo biomagnetico è dovuta al fatto che questa tecnica offre un’alta risoluzione spaziale e sembra fornire informazioni complementari rispetto alle sole registrazioni elettriche. Fino ad oggi l’interesse degli studiosi si è concentrato su due differenti fenomeni cardiaci: 1) lo studio dell’attività del sistema di conduzione atrioventricolare e 2) lo studio della depolarizzazione ventricolare anormalmente ritardata (late potentials). L’interesse clinico per lo studio non invasivo del sistema di His-Purkinje (HPS) è ben noto. Registrazioni cliniche non invasive di late potentials sono particolarmente desiderabili in quanto possono essere preziosi indicatori di rischio di morte improvvisa. In questo lavoro si presenta una rassegna sullo stato delle ricerche in entrambi i campi d’indagine.
    Notes: Summary The fundamental motivation for investigating cardiac electrophysiological phenomena by means of the biomagnetic method has been that this technique should have added spatial resolution and provided complementary information as opposed to electric recordings only. So far the interest of experimentalists has been concentrated on two different kinds of cardiac phenomena: 1) the study of the activity of the cardiac conduction system and 2) of abnormally delayed ventricular depolarization (late potentials). The clinical interest for the noninvasive investigation of the His-Purkinje system (HPS) is well known. Noninvasive clinical recording of late potentials is particularly desirable as they seem to be precious markers for risk of sudden death. A review of the state of research in both fields is presented in this paper.
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    URL: http://dx.doi.org/10.1007/BF02455927
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    Magnetic measurements and modelling for the investigation of the human-heart conduction system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 280-290 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Ein dal 1980 è iniziato uno studio sistematico dell’attività del sistema di His-Purkjnje (HPS) su soggetti normali e patologici con il metodo biomagnetico. Allo scopo di risolvere il problema di quanta parte dei segnali misurati sia attribuibile al sistema di His-Purkinje e quanta piuttosto alla ripolarizzazione atriale, è stata recentemente sviluppata una strumentazione appositamente disegnata per misure sul HPS e con una sensibilità di $$20fT/\sqrt {Hz}$$ nella banda di frequenze interessanti ((0.5÷300) Hz). Al contempo si è altresí sviluppato un nuovo modello teorico in stretta corrispondenza con le caratteristiche anatomiche del HPS che fornisce una distribuzione di campo magnetico sul torace in buon accordo qualitativo con i risultati sperimentali.
    Notes: Summary Since 1980, systematic investigations of the activity of the His-Purkinje system (HPS) by the biomagnetic method have been reported on both normal subjects and patients affected by different kinds of conduction disturbances. A first attempt to interpret the experimental results by means of a theoretical model satisfactorily accounted for the measured «ramp» patterns. Moreover, a good temporal coincidence was observed between magnetic signals and invasively recorded His bundle electrograms (HBE). An alternative explanation of the «ramp» pattern, in terms of atrial repolarization, has been recently proposed on the basis of animal experimental investigation. In order to try to solve this problem, we have carried out a twofold approach: a new second-order gradiometer, specifically designed for HPS activity investigation has been successfully set up and tested; it provides a sensitivity of $$20fT/\sqrt {Hz}$$ in the band width of interest ((0.5÷300) Hz). Second, a new model based on a closer correspondence to anatomical features of the HPS has been developed. This model provides well-defined patterns which are in quite good agreement with experimental results.
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    URL: http://dx.doi.org/10.1007/BF02455931
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    The mapping of the measured cardiac electric potential and magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 311-323 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si registra la distribuzione sia del potenziale elettrico cardiaco sulla superficie del corpo che del campo magnetico cardiaco vicino al torace e alla schiena in momenti fissi del ciclo cardiaco. Le caratteristiche generali di entrambi i tipi di mappa sono semplici e riproducibili, inoltre ciascuno di essi fornisce informazioni differenti.
    Notes: Summary The distribution of both the cardiac electric potential on the body surface and the cardiac magnetic field near the chest and back is recorded at fixed time instants of the heart cycle. The general features of both types of maps are simple and reproducible, moreover they both reveal different information.
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    URL: http://dx.doi.org/10.1007/BF02455934
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    The influence of inhomogeneities on the cardiac-magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 324-339 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati eseguiti calcoli numerici sul campo magnetico generato dal cuore durante la depolarizzazione ventricolare. Lo scopo di questo lavoro è studiare il contributo d’inomogeneità nel conduttore di volume al campo totale e stabilire l’influenza dei gradiometri usati nelle registrazioni sperimentali.
    Notes: Summary Numerical computations were performed on the magnetic field generated by the heart during ventricular depolarization. The purpose of this study was to investigate the contribution of inhomogeneities in the volume conductor to the total field and to establish the influence of gradiometers as used in experimental recordings.
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    URL: http://dx.doi.org/10.1007/BF02455935
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    High-resolution magnetocardiographic recordings of theST segment in patients with electrical late potentials (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 340-345 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione, registrato in 22 pazienti affetti da pregresso infarto del miocardio, ha permesso di rilevare in 3 casi la presenza di segnali di ampiezza tra 0.4 e 3 pT temporalmente correlati a depolarizzazioni tardive elettriche. Si discutono de differenze tra segnali magnetici ed elettrici e il loro possibile significato fisiopatologico.
    Notes: Summary High-resolution magnetocardiograms of patients with recent myocardial infarction have been recorded. In three cases, signals have been found in theST segment that are time correlated with simultaneously recorded late electric potentials.
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    URL: http://dx.doi.org/10.1007/BF02455936
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    On the influence of the volume conductor in magnetocardiography: an experimental approach (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 346-355 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Per studiare l’effetto della geometria del conduttore di volume, sono stati compiuti esperimenti usando cuori di coniglio isolati. È stato osservato un aumento del segnale magnetico con l’aumentare della dimensione del conduttore di volume. Si discutono i risultati usando un dipolo di corrente a origine fissa e un modello di sorgente di tensione per il cuore.
    Notes: Summary To study the effect of the volume conductor geometry on the MCG, experiments using isolated rabbit hearts were done. An increase of the magnetic signal when increasing the volume conductor’s size was observed. The results are discussed by using a fixed-origin current dipole and a voltage source model for the heart.
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    First magnetic measurements of action currents in isolated cardiac Purkinje fibers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 368-378 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico associato col potenziale d’azione in un fascio di fibre cardiache di Purkinje isolate. Le nostre scoperte dimonstrano la fattibilità dell’uso di tecniche magnetiche per misurare le correnti assiali in un gruppo di cellule cardiache ad attività spontanea.
    Notes: Summary We present the first measurements of the magnetic field associated with the action potential in a bundle of isolated cardiac Purkinje fibers. Our findings demonstrate the feasibility of using magnetic techniques to measure the axial current in a bundle of spontaneously active cardiac cells.
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    URL: http://dx.doi.org/10.1007/BF02455939
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    Inferences concerning anatomy and physiology of the human brain based on its magnetic field (1983)
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    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 379-409 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetic (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riesaminano le ricerche sul campo magnetico indotto compiute negli ultimi due anni. Questi studi hanno mostrato che la tecnica magnetica si puó usare 1) per rivelare aspetti complementari delle fonti di corrente comuni al potenziale indotto, 2) per identificare l’organizzazione della corteccia cerebrale e delle arce subcorticali e 3) per misurare le proprietà funzionali delle aree neurali attive le cui posizioni sono identificate.
    Notes: Summary Research in the evoked magnetic field reported in the last two years is reviewed. The studies have shown that the magnetic technique may be used 1) to reveal complementary aspects of the current sources common to evoked potential, 2) to identify the organization of the cerebral cortex and subcortical areas of the brain and 3) to measure functional properties of the active neural areas whose locations are identified.
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    Retinotopic map on the visual cortex for eccentrically placed patterns: First noninvasive measurement (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 410-419 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il campo magnetico corticale osservato, suscitato da uno stimolo presentato a varie eccentricità nel campo visivo, è stato interpretato come derivante da dipoli di corrente lungo la scissura longitudinale. La profondità della sorgente aumenta con l’aumento dell’eccentricità, in accordo con la classica mappatura retinotopica.
    Notes: Summary The observed cortical magnetic field evoked by a stimulus presented at various eccentricities in the visual field was interpreted as arising from current dipoles along the longitudinal fissure. The depth of the source increased as the eccentricity was increased, in agreement with the classical retinotopic map.
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    Neuromagnetic localization of two components of the transient visual evoked response to patterned stimulation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 420-428 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si esamiano i componenti elettrici e magnetici della risposta stimolata visiva del cervello, con picchi a 120 e 180 ms dopo lo stimolo. I risultati mostrano che entrambi i componenti magnetici sono localizzati nella corteccia occipitale superficiale tangenziale al cuoio capelluto. La distribuzione diM120 suggerisce che i generatori dei componenti elettrici e magnetici sono correlati, ma il campo magnetico elettrico registrato è una modificazione elaborata di quello prodotto dalla sorgente.
    Notes: Summary Corresponding electrical and magnetic components of the brain’s visual evoked response peaking at 120 and 180 ms poststimulus are examined. Results show that both magnetic components are localized in the superficial occipital cortex tangential to the scalp. The distribution ofM120 suggests that the generators for the electrical and magnetic components are related, but the electrical field recorded is an elaborate modification of that produced by the source.
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    URL: http://dx.doi.org/10.1007/BF02455942
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    Somatosensory evoked magnetic fields: Mappings and the influence of the stimulus repetition rate (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 429-437 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Campi magnetici indotti dalla sensibilità somatica sono stati confrontati con i corrispondenti potenziali elettrici sul cuoio capelluto allo scopo di studiare le loro sorgenti neurali. Le mappature delle risposte magnetiche hanno mostrato attività a livello delle cortecce di sensibilità somatica primarie e secondarie. Ulteriori sorgenti oltre a queste aree sembrano essere coinvolte nella generazione dei potenziali del cuoio capelluto a vertice somatosensoriali.
    Notes: Summary Somatosensory evoked magnetic fields were compared with corresponding electric scalp potentials in order to study their neural sources. Mappings of the magnetic responses showed activity at the primary and secondary somatosensory cortices. Additional sources besides these areas seem to be involved in the generation of the somatosensory vertex scalp potentials.
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    URL: http://dx.doi.org/10.1007/BF02455943
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    Some tentative model considerations based on experimental neuromagnetic data (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 438-459 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si presentano alcuni tentativi di considerazioni modello, basati sul concetto di dipolo di corrente equivalente per tener conto delle risposte sonore stimolate osservate, con lo scopo di tentare un confronto delle variazioni in ampiezza e latenza con calcoli basati sul modello di nervo altamente semplificato di Rall. Si presenta un’analisi fenomenologica dei dati sperimentali sul campo magnetico sonoro tardo evocato dalla corteccia uditiva umana. Qui si pone l’accento sulle relazioni tra le proprietà del segnale (per esempio, ampiezza e latenza) e tra le proprietà del segnale e le proprietà dello stimolo (per esempio, ampiezza/latenza e frequenza in discesa relativa Δf/f per uno stimolo con frequenza in discesa) piuttosto che su problemi correlati con la posizione del dipolo di corrente equivalente, per esempio l’organizzazione tonotopica discussa da Elberlinget al. e Romaniet al. Si presentano alcuni risultati di un calcolo numerico basato su un modello a cavo lineare e li si confronta con i risultati sperimentali.
    Notes: Summary In this paper we present some tentative model considerations, based on the concept of an equivalent current dipole to account for observed auditory evoked responses, with the aim of attempting a comparison of variations in amplitude and latency with calculations based on Rall’s greatly simplified nerve model. A phenomenological analysis of experimental data on the late, auditory evoked magnetic field from the human auditory cortex is presented. The emphasis is here placed on relations between signal properties (e.g. amplitude and latency) and between signal properties and stimulus properties (e.g. amplitude/latency and relative frequency glide Δf/f for a frequency glide stimulus) rather than on questions related to the location of the equivalent current dipole,e.g. the tonotopic organization discussed by Elberlinget al. and by Romaniet al.. Some results of a numerical calculation based on a linear-cable model are presented and compared with experimental results.
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    URL: http://dx.doi.org/10.1007/BF02455944
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    Studies of auditory evoked magnetic and electric responses: Modality specificity and modelling (1983)
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    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 471-483 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le sorgenti di risposte uditive magnetiche ed electtriche stimolate sono state formate con dipoli a corrente multipli. L’attività a livello delle cortecce uditive, 2.6 cm al di sotto della calotta cranica, spiega la distribuzione di campo osservata $$\overline {N100m}$$ . Un’ulteriore sorgente di corrente vicino al vertice è necessaria per spiegare le corrispondenti distribuzioni di potenziale. La posizione delle sorgenti di corrente di $$\overline {N100m}$$ non ha mostrato alcuna dipendenza sistematica dalla frequenza tonale.
    Notes: Summary The sources of auditory evoked electric and magnetic responses were modelled with multiple current dipoles. The activity at the auditory cortices, 2.6 cm beneath the skull, explains the observed $$\overline {N100m}$$ field distribution. An additional current source near the vertex is needed to explain the corresponding potential distributions. The locations of the current sources of $$\overline {N100m}$$ did not show any systematic dependence on the tonal frequency.
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    URL: http://dx.doi.org/10.1007/BF02455946
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    Auditory evoked magnetic fields: a replication, with comments on the magneticP50 analog (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 460-470 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati campi magnetici uditivi indotti (AEF) e potenziali uditivi indotti EEG (AEP) dalle regioni corticali uditive destra e sinistra di 12 soggetti normali adulti. Il sensore magnetico era un gradiometro SQUID a forma di otto con una linea di base di 4 cm orientato in modo da essere massimamente sensibile a un dipolo di corrente orientato perpendicolarmente alla fissure di Sylvio. Gli stimoli erano impulsi sonori di 1 kHz, lunghi 100 ms con un intervallo modale tra stimoli di 700 ms emessi a livelli di pressione sonora di 40, 60, 80 e 100 dB. Si è trovato che l’ampiezza AEF è correlata all’intensità dello stimolo in modo quadratico, l’ampiezza AEP in modo, lineare. Gli AEF erano di ampiezza maggiore in risposta alla stimolazione contralaterale che in risposta alla stimolazione ipsilaterale. Gli AEP non presentano questa relazione. In un secondo esperimento gli AEF e AEP dell’emisfero destro in risposta al tono di stimolazione nell’orecchio controlaterale in questi 12 soggetti sono stati combinati con dati simili precedenti su 24 soggetti, ottenendo cosí un totale di 36 soggetti, per esaminare la comparabilità della forma dell’onadaP50 di AEP e dell’analogaP50 di AEF. Si è trovato che la latenza dellaP50 decrese in funzione dell’intensità crescente dello stimolo sia per AEF che per AEP, e che la latenza diP50 è decisamente inferiore nelle registrazioni magnetiche rispetto alle registrazioni del potenziale.
    Notes: Summary Auditory evoked magnetic fields (AEFs) and EEG auditory evoked potentials (AEPs) were recorded from left and right auditory cortical regions of 12 normal adult subjects. The magnetic sensor was a figure-eight SQUID gradiometer with a 4 cm baseline oriented so as to be maximally sensitive to a current dipole oriented normal to the Sylvian fissure. Stimuli were 100 ms long 1 kHz tone pips with a modal interstimulus interval of 700 ms delivered at sound pressure levels of 40, 60, 80 and 100 dB. AEF amplitude was found to be related to stimulus intensity in a quadratic fashion, AEP amplitude in a linear fashion. AEFs were of larger amplitude in response to contralateral as compared to ipsilateral stimulation. AEPs did not exhibit such a relationship. In a second experiment right-hemisphere AEFs and AEPs in response to contralateral ear tone stimulation in these 12 subjects were combined with similar previous data from 24 subjects, providing a total of 36 subjects, to examine the comparability of the AEPP50 wave form and the AEFP50 analog. The latency of theP50 was found to decrease as a function of increasing stimulus intensity for both AEFs and AEPs, and theP50 latency was consistently shorter in magnetic compared to potential recordings.
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    URL: http://dx.doi.org/10.1007/BF02455945
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    Cerebral magnetic fields associated with voluntary limb movements in man (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 484-494 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto I movimenti volontari degli arti sono preceduti da spostamenti MEG che cominciano già 1.2s prima del movimento. Questi spostamenti invertono la polarità sull’area di rappresentazione della corteccia motoria dell’arto in questione.
    Notes: Summary Voluntary limb movements are preceded by MEG shifts beginning even as early as 1.2 s before the movement. These shifts reverse polarity above the cortical motor representation area of the limb concerned.
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    URL: http://dx.doi.org/10.1007/BF02455947
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    Slow magnetic fields of the brain preceding movement and speech (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 495-504 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati i campi magnetici del cervello che precedono i movimenti autonomi delle dita della mano, del piede e della dita del piede stesso, i movimenti delle dita della mano e del piede causati da uno stimolo e la parola. Sono stati trovati lenti spostamenti dei campi magnetici con morfologia simile ai coincidenti potenziali elettrici, ma con distribuzioni molto diverse. Si discutono le deduzioni ottenute dai dati sulla localizzazione dei generatori cerebrali.
    Notes: Summary Magnetic fields of the brain were recorded preceding selfinitiated finger, foot, toe movements, stimulus-triggered finger and toe movements, and speech. Slow magnetic-field shifts were found with morphology similar to coincident electrical potentials, but with very different distributions. Inferences from the data about localization of cerebral generators were discussed.
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    URL: http://dx.doi.org/10.1007/BF02455948
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    Magnetic fields associated with the brain’s response to infrequent events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 505-511 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato il campo magnetico prodotto dal cervello prendendo in considerazione una varietà di eventi rari. Si riporta il carattere temporale della risposta a un raro stimolo uditivo. Il campo magnetico appare offrire un’utile nuova sonda dell’attività endogena nel cervello umano.
    Notes: Summary We have studied the magnetic field produced by the brain when attending to a variety of rare events. The temporal character of the response to a rare auditory stimulus is reported. The magnetic field appears to offer a useful new probe of endogeneous activity in the human brain.
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    URL: http://dx.doi.org/10.1007/BF02455949
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    Magnetic study of the spontaneous brain activity of normal subjects (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 538-546 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Uno studio sull’attività spontanea del cervello in soggetti normali è stato eseguito con il metodo neuromagnetico. Sono stati usate 2 diverse strumentazioni per le misure magnetiche. Ambedue usavano gradiometri di second’ordine disegnati specificatamente per gli studi sul cervello: 2.9 cm di diametro, 5 cm di baseline. Uno SQUID r.f. e uno SQUID d.c. erano accoppiati ai gradiometri. I livelli di rumore misurati sono stati rispettivamente di $$40fT/\sqrt {Hz}$$ e $$25fT/\sqrt {Hz}$$ . In alcuni soggetti sono state effettuate mappe di campi magnetici generati dall’attività spontanea del cervello. Le mappe dell’ampiezza media dei segnali del ritmo α hanno mostrato 2 massimi dell’attività su 2 regioni simmetriche dello scalpo. Comunque, malgrado una generale simmetria fra gli emisferi, la complessità delle mappe misurate suggerisce una corrispondente complessità dei generatori responsabili dell’attività α.
    Notes: Summary An investigation of the spontaneous brain activity from normal subjects has been carried out by means of the neuromagnetic method. Two different systems were used for magnetic measurements. Both used 2nd-order gradiometers specifically designed for brain studies: 2.9 cm diameter, 5 cm baseline. A r.f. SQUID and a d.c. SQUID were coupled to the gradiometers. The measured noise levels are $$40fT/\sqrt {Hz}$$ and $$25fT/\sqrt {Hz}$$ , respectively. Thorough magnetic mapping of the spontaneous activity was performed on a few subjects. By mapping the average amplitude of the α-rhythm signals two maxima of activity over two symmetric regions of the scalp were clearly observed. Despite a general symmetry between hemispheres, however, the complexity of the measured maps suggests a corresponding complexity of the generators responsible for α-activity.
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    Alternatives to the SQUID magnetometer for some biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 214-223 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si discutono magnetometri del tipo del flussometro elettronico e di risonanza (precisione libera, pompata otticamente) che possono in qualche caso sostituire il magnetometro SQUID. Si descrivono i princípi di funzionamento, la sensibilità, l’intervallo dinamico e la risposta di frequenza. Si dà un accenno riguardo l’applicazione di questi magnetometri nelle misurazioni biomagnetiche.
    Notes: Summary Flux gate and resonance type of magnetometers (free precession, optically pumped), which can in some cases replace the SQUID magnetometer, are discussed. The principles of operation, sensitivity, dynamical range and frequency response are described. The application of these magnetometers for biomagnetic measurements is mentioned.
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    The magnetic field produced by the conduction system of the human heart (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 255-265 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata sfruttata la risoluzione spaziale del sensore magnetico per fornire stime numeriche del contributo atriale ai campi magnetici registrati esattamente prima della depolarizzazione ventricolare. Si trova che il contributo è piccolo, e questo rafforza l’interpretazione originale secondo la quale questi campi derivano principalmente dal sistema di conduzione del cuore.
    Notes: Summary We have exploited the spatial resolution of the magnetic sensor to provide numerical estimates of the atrial contribution to magnetic fields recorded just prior to ventricular depolarization. The contribution is found to be small, strenghening our original interpretation that such fields originate mostly in the conduction system of the heart.
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    URL: http://dx.doi.org/10.1007/BF02455929
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    High-resolution isofield mapping in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 291-300 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano i risultati preliminari ottenuti costruendo mediante computer mappe di distribuzione di campo magnetico sulla base di registrazioni ad alta risoluzione effettuate con magnetometro superconduttore. La procedura è stata applicata per esaminare i MCG di 16 pazienti affetti da pregresso infarto del miocardio. Sulla base di questa elaborazione è stato possibile dividere i pazienti in due classi, una delle quali contiene tutti i pazienti con depolarizzazioni tardive.
    Notes: Summary A possible clinical application of a high-resolution magnetic isofield contour mapping technique in cardiography is discussed. Preliminary results are presented in applying this technique to patients with recent myocardial infarction. The patients could be divided into two classes; one of them contains patients with electrical late potentials as a subclass.
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    URL: http://dx.doi.org/10.1007/BF02455932
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    Magnetic measurements of action currents in an isolated lobster axon (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 512-516 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico prodotto da correnti di azione che si propagano lungo l’assone singolo di un nervo gigante. Questi dati sono stati ottenuti con un trasduttore a bobina toroidale e un amplificatore o semiconduttore a temperatura ambiente.
    Notes: Summary We present the first measurements of the magnetic field produced by action currents propagating along a single giant nerve axon. These data were obtained with a toroidal pick-up coil and a room temperature semiconductor amplifier.
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    URL: http://dx.doi.org/10.1007/BF02455950
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    Clinical magnetoencephalography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 517-537 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Finora la magnetoencefalografia spontanea (MEG) in soggetti normali e patologici non è stata investigata a fondo. Si conoscono pochissimi contributi in questo campo. A parte il lavoro del gruppo di biomagnetismo di Roma, il solo contributo clinico finora è stato quello di Hughes e collaboratori che era abbastanza limitato nel numero e nella scelta dei soggetti studiati. La nostra esperienza condotta fin dal 1980 su un gran numero di casi (principalmente epilessie focali) mostra che il MEG può evidenziare attività significative anche se non sono presenti anormalità EEG; esso ha inoltre una risoluzione spaziale maggiore rispetto all’EEG. I foci epilettici mostrano un’area limitata di attività massima. Finora non è stata osservata nessuna evidenza sperimentale di una differente distribuzione delle ampiezze del campo sullo scalpo. La risoluzione spaziale del MEG riguarda anche la possibilità di risolvere la morfologia dei segnali EEG (per esempio onde aguzze EEG risolte in gruppi di spikes dal MEG) o di separare topograficamente le anormalità EEG mescolate e non ben localizzate (per esempio, attività delta ed epilettiche mescolate nell’EEG e discriminate nel MEG). I migliori risultati si osservano quando la localizzazione è nella corteccia esterna. Dopo una descrizione del materiale studiato, si sottolinea l’importanza dei risultati ottenuti per la prima volta in casi di epilessie focali.
    Notes: Summary So far spontaneous magnetoencephalography (MEG) in normal and pathological subjects has not been deeply investigated. Very few contributions in this field are available. Aside from the work of the Rome biomagnetic group in this field, the only clinical contribution up to now has been that of Hughes and co-workers which was rather limited in the number and in the selection of subjects investigated. Our experience, carried out since 1980 on a large number of cases—mainly focal epilepsies— shows that the MEG may evidence significant activities even if EEG abnormalities are not present and has a higher spatial resolution with respect to the EEG. Epileptic foci show a limited area of maximal activity. So far no experimental evidence of a different distribution of field amplitude over the scalp has been observed. The spatial resolution of the MEG also regards the possibility of resolving the morphology of EEG signals (for instance, EEG sharp waves resolved into groups of spikes by MEG) or topographically separate EEG abnormalities mixed up and not well localized (for instance, delta and epileptic activities mixed up in the EEG, but differently in the MEG). The best results are observed when the localization is in the outer cortex. After a description of the material studied, the importance of the results obtained for the first time in cases of focal epilepsies is outlined.
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    Localization of epileptic foci by means of biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 547-557 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Durante l’ultimo anno gli autori hanno condotto una ricerca sistematica su un gran numero di soggetti patologici registrando simultaneamente l’EEG e il MEG. La presente versione del nostro apparato sperimentale permette di effettuare misure MEG con un solo sensore magnetico, impedendo la rilevazione simultanea di attività MEG su punti differenti della testa. Ciò ha condotto gli autori a concentrarsi sulle epilessie focali. Fin dalle prime misure il sensore magnetico ha dimostrato un notevole potere localizzante, rafforzando l’interesse per la localizzazione in casi patologici. In questo lavoro si riportano risultati che sembrano confermare la straordìnaria capacità delle misure MEG nel localizzare sorgenti di attività cerebrali patologiche in casi di epilessie focali.
    Notes: Summary During the last year the authors have been carrying out a systematic investigation on a large number of pathological subjects simultaneously recording the EEG and the MEG. The present version of our experimental apparatus allows MEG measurements with only one magnetic detector, thus preventing the detection of simultaneous MEG activities over different points of the head. This has led the authors to concentrate upon focal epilepsies. Since the first measurements a remarkable localizing power was shown by the magnetic detector, thus strengthening the interest in pathological localization. In this contribution we report results which seem to confirm the extraordinary capability of MEG measurements to localize sources of pathological brain activities in cases of focal epilepsies.
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    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
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    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
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    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
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    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
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    Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl (1983)
    Springer
    Cell & tissue research 234 (1983), S. 411-425 
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    ISSN: 1432-0878
    Keywords: Intestines (chicken) ; Innervation ; Catecholamines ; Adrenergic fibres ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a ‘ typical’ adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.
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    Ultrastructural identification of corticotropes of the fetal rat (1983)
    Springer
    Cell & tissue research 234 (1983), S. 427-437 
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    ISSN: 1432-0878
    Keywords: Corticotropes ; Rat fetus ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.
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    Cyclophosphamide-induced changes in rodent odontogenesis (1983)
    Springer
    Cell & tissue research 234 (1983), S. 679-689 
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    ISSN: 1432-0878
    Keywords: Odontogenesis ; Rats ; Cyclophosphamide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclophosphamide-induced changes in rodent odontogenesis were investigated by light and electron microscopy in four-day-old Sprague Dawley rats given one injection of 40 mg/kg of body weight of cyclophosphamide and killed at intervals of one hour, one day, one week and two weeks. Incisor and molar teeth were dissected from the animals, fixed in 2.0% glutaraldehyde in 0.1 M sodium cacodylate with 3.4% sucrose, and subsequently some were incubated for alkaline phosphatase reaction, and embedded in Spurr's medium for sectioning at light- and electron-microscopic levels. From three days a cell-sparse zone was created in the pulp in the growing end of the tooth and progressive cellular changes were observed which became more severe in the one-week and two-week specimens. Subodontoblast and adjacent pulpal cells were the most affected showing nuclear changes, damage to, or loss of, organelles, and inclusion bodies. Odontogenic epithelium was less affected and odontoblasts appeared to be unaffected by the drug. A new irregular matrix was laid down in the defect area and seemed to be the product of depolarized odontoblasts. This new matrix showed alkaline phosphatase activity, as did the cells embedded in it, and later it became mineralized. It is speculated that the polarity of odontoblasts might be maintained by an intact subodontoblastic layer; when this is lost the odontoblasts become depolarized and capable of secreting matrix from both ends.
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    Isolation of metabolically active endothelial cells in high yield from bovine cavernous bodies (1983)
    Springer
    Cell & tissue research 232 (1983), S. 579-591 
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    ISSN: 1432-0878
    Keywords: Cavernous bodies ; Endothelial cells ; Respiratory activity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Work on endothelial cells has been limited by the availability of procedures for obtaining such cells in quantities adequate for direct in vitro analysis. The present paper describes a method for the isolation of endothelial cells from bovine cavernous bodies. A number of cells ranging from 2.5 to 4 × 108 per animal has been obtained. The cells were identified as follows 1) presence of the “Weibel and Palade” bodies in the isolated cells, 2) “cobblestone” appearance of cell cultures, and 3) presence of factor VIII, as demonstrated by immunofluorescence assays. The cell viability at the end of the purification procedure was tested 1) by dye-exclusion tests and 2) by metabolic assays. Features of this preparation are 1) the very high yield of viable endothelial cells, 2) the absence of contamination by fibroblasts and smooth muscle cells and a very low contamination by erythrocytes and 3) the fine dispersion of the isolated cells. These properties allow functional and subcellular fractionation studies on freshly isolated endothelial cells of microvascular origin.
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    URL: http://dx.doi.org/10.1007/BF00216430
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    Ultrastructural morphometry of the myocardium of Thunnus alalunga (1983)
    Springer
    Cell & tissue research 233 (1983), S. 427-438 
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    ISSN: 1432-0878
    Keywords: Myocardium ; Thunnus alalunga ; Ultrastructure ; Mitochondria ; Myofibrils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4–6 μm diameter) than the spongy layer (2.5–5 μm diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
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    URL: http://dx.doi.org/10.1007/BF00238308
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    Ultrastructural and immunohistochemical studies of rat epididymis (1983)
    Springer
    Cell & tissue research 233 (1983), S. 523-537 
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    ISSN: 1432-0878
    Keywords: Epididymis (rat) ; Myosin ; Actin ; Fibronectin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5–6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the “A” cell granules of the endocrine pancreas and gut mucosa cells.
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    URL: http://dx.doi.org/10.1007/BF00212222
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    The structure and function of the nematocysts of Chironex fleckeri Southcott, 1956 (1983)
    Springer
    Cell & tissue research 233 (1983), S. 563-577 
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    ISSN: 1432-0878
    Keywords: Nematocysts ; Structure ; Ultrastructure ; Function ; Cubozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microbasic p-mastigophores, euryteles of two size groups, holotrichous isorhizas and atrichous isorhizas, comprise the cnidom of Chironex fleckeri, a cubozoan that has been responsible for several human fatalities. In its undischarged state each microbasic mastigophore of C. fleckeri consists of a capsule containing matrix and an inverted tube possessing a smooth-walled butt which is loosely coiled helically and which narrows to form a thread that is tightly coiled helically and markedly pleated. Both butt and thread carry three helices of spines and contain a granular matrix. During discharge, the proximal butt spines form initially a piercing stylet. Granular material from the butt and thread is released prior to the release of capsular material. Each eurytele possesses a tube with a butt composed of three bulbs, the middle bulb bearing long spines. Each holotrichous isorhiza possesses a coiled tube bearing small spines along its length. Each atrichous isorhiza exhibits a tube that is devoid of spines and loosely folded in the undischarged condition. The probable role of each type of nematocyst is inferred from its structure and features that enable the ready separation of the nematocysts of C. fleckeri from those of scyphozoan jellyfish are discussed.
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    URL: http://dx.doi.org/10.1007/BF00212225
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    Ciliary epithelia of the mammalian eye in cultured explants (1983)
    Springer
    Cell & tissue research 233 (1983), S. 629-638 
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    ISSN: 1432-0878
    Keywords: Ciliary process ; Cultured explant ; Epithelial cells ; Ultrastructure ; Bovine and rabbit eyes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the expiants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of nonpigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flatened cells in the outermost layer are derived from pigmented epithelium.
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    URL: http://dx.doi.org/10.1007/BF00212230
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    Ultrastructural observations on the formation of follicles in the human fetal thyroid (1983)
    Springer
    Cell & tissue research 233 (1983), S. 693-698 
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    ISSN: 1432-0878
    Keywords: Thyroid gland ; Human fetus ; Follicles ; Ultrastructure ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyroid glands from 40 human fetuses ranging from 30 to 175 mm in length were examined by electron microscopy. At the 30 mm stage, the cells are arranged in cords or clusters and contain numerous free ribosomes. The rough-surfaced endoplasmic reticulum (RER) is poorly developed and the Golgi complex consists of saccules, smooth and coated vesicles. Mitochondria, microfilaments, glycogen particles, occasional lysosome-like structures, and single cilia are observed. At sites of incipient follicle formation, intercellular clefts containing interdigitating microvilli, delimited by junctional complexes, are evident. In addition, the apical region of some cells contains vacuoles. At the 50-mm stage, intercellular clefts are more apparent, some of them organized into small follicles through the enlargement of the lumen, the incorporation of additional cells, and the formation of a basal lamina. With increasing gestational age, more follicles are established. The lumina vary from round to clover-leaf shaped and have an electron-dense content. Cisternae of RER are dilated and contain flocculent material. The Golgi complex is more extensive, and lysosome-like structures are more numerous. By the 100-mm stage, the follicular cells appear morphologically well differentiated. The results demonstrate an extracellular origin of the follicular lumen in the human fetal thyroid.
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    URL: http://dx.doi.org/10.1007/BF00212236
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    Ultrastructural immunocytochemical localization of fibronectin in the developing rat lung (1983)
    Springer
    Cell & tissue research 234 (1983), S. 165-177 
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    ISSN: 1432-0878
    Keywords: Fibronectin ; Lung ; Development ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a previous study changes in the macrodistribution of fibronectin during rat-lung development were examined. Using the peroxidase-antiperoxidase immunocytochemical technique, we have demonstrated the presence of fibronectin in embryonic, neonatal, and adult rat lung at the ultrastructural level. In the embryo, fibronectin is found both in an intra-and extracellular association with isolated pneumoblasts, and in a periodic distribution along the basal lamina. The neonate displays fibronectin in an intracellular association with early type-I cells and on their basal and luminal surfaces, but not in association with type-II cells. Neonatal basal lamina is diffusely labeled by anti-fibronectin antiserum. Fibronectin in adult tissue is found both intracellularly and on the basal and luminal surfaces of type-I cells but not in type-II cells. The basal lamina and interstitial connective tissue are slightly or non-reactive. These observations confirm and extend our initial suggestion that fibronectin is involved in rat-lung development.
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    URL: http://dx.doi.org/10.1007/BF00217410
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    Electron microscopy of extracellular materials during the development of a sea star, Patiria miniata (Echinodermata: Asteroidea) (1983)
    Springer
    Cell & tissue research 234 (1983), S. 193-200 
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    ISSN: 1432-0878
    Keywords: Sea star ; Development ; Cuticle ; Extracellular materials ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of conspicuous extracellular materials during the life history of a sea star (Patiria miniata) is described. The outer surface of the developing sea star is covered by two morphologically different cuticles that appear sequentially during ontogeny. The primary cuticle, which is about 120 nm thick and two-layered, is present from mid-blastula through the end of the larval stage. The secondary cuticle, which is about 1 μm thick and three-layered, first appears on the epidermis of the rudiment region of the larva and, after metamorphosis, covers the entire epidermis of the juvenile and adult stages. During ontogeny, there are only two conspicuous gut cuticles: the first lines the newly invaginated archenteron at the start of the gastrula stage, and the second lines the esophagus during the larval stage. A blastocoelic basal lamina first appears at mid-blastula and persists as subectodermal and subendodermal basal laminae. Ruthenium red-positive granules are detectable between the lateral surfaces of adjacent ectodermal cells during part of the gastrula stage; this transient intercellular material may possibly aid in lateral adhesion between cells.
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    URL: http://dx.doi.org/10.1007/BF00217412
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    Changes in plastid ultrastructure during iron nutrition-mediated chloroplast development (1983)
    Springer
    Protoplasma 114 (1983), S. 85-92 
    Details
    ISSN: 1615-6102
    Keywords: Chloroplasts ; Iron stress ; Sugar beet ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When grown in iron-free media, the youngest leaves of healthy green sugar beet plants became completely yellow after 6 to 8 days. This chlorosis was quickly reversed by resupplying iron. A study of the ultrastructure of the iron -stressed leaves revealed apparently normal subcellular organization except for the plastids which were small and undeveloped, contained a rudimentary, disorganized grana-fretwork and clusters of vesicles in the periphery. Twelve to 16 hours after resupply of iron, aggregates of phytoferritin were observed in the stroma, and the granal fretwork underwent further development. There was an increased orientation of the membranes along the long axis of the plastids and an increase in the length of the individual grana stacks. By 48 hours, leaf chlorophyll content was about 40% of the control. At the ultrastructural level, parallel alignment of membrane orientation was complete and the grana stacks began to increase in the number of thylakoids per stack.
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    Nucleolus-associated bodies (karyosomes) in dividing and differentiating plant cells (1983)
    Springer
    Protoplasma 115 (1983), S. 1-10 
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    ISSN: 1615-6102
    Keywords: Brassica napus ; Nucleolus ; Pisum sativum ; Ultrastructure ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The karyosome is a spherical body up to 1 μm in diameter that lies on the nucleolus of certain plant species, particularly those with a relatively low nuclear DNA content and an areticulate nuclear structure. It can be seen in the light microscope after impregnation with silver; in the electron microscope its structure consists of fibrillo-granular material. Nucleoli of cells in root apices may bear 0, 1, or 2 karyosomes. The frequency with which these numbers of karyosomes are observed depends on the location of the cells within the apex. In roots ofPisum sativum andZea mays the nucleoli of both slowly-dividing and young differentiating cells bear karyosomes more frequently than the nucleoli of rapidly-dividing cells. The karyosome seems to adopt a preferred location on the nucleolus, lying most frequently on the nucleolar surfaces directed towards the apex or base of the root. The origin and functional significance of the karyosome are discussed. Morphological evidence suggests that it may be material that formerly was part of a fibrillar centre.
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    Stomatal pore and cuticle formation inFunaria (1983)
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    Protoplasma 116 (1983), S. 1-13 
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    ISSN: 1615-6102
    Keywords: Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
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    URL: http://dx.doi.org/10.1007/BF01294225
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    Microtubule organization and morphogenesis in young spores of the mossTetraphis pellucida Hedw (1983)
    Springer
    Protoplasma 116 (1983), S. 115-124 
    Details
    ISSN: 1615-6102
    Keywords: Microtubules ; Moss ; MTOC ; Sporogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubule systems appear sequentially at the distal and proximal poles of tetrad members during mid-sporogenesis in the mossTetraphis pellucida Hedw. The distal microtubule system emanates from a microtubule organizing center (MTOC) located between the single plastid and the nucleus. The distal MTOC and associated microtubules, which appear immediately after cytokinesis, are ephemeral and do not appear to be associated with the deposition of exine occuring at the same time. The proximal microtubule system, which appears slightly later than the distal system, is a more stable component of mid-sporogenesis. The proximal MTOC is an irregularly lobed, patelliform aggregation of electron-dense granules located beneath the plasma membrane at the proximal spore pole. Several bundles of microtubules radiate from the proximal MTOC and traverse the cell, enclosing the nucleus in an cone of microtubules. The proximal microtubule system is thought to function in aperture development and organelle migration. The relatively large nucleus migrates a short distance in the small spore early in the tetrad stage and maintains its acentric position at the proximal pole throughout later stages of sporogenesis. The plastid migrates later in the tetrad stage from its meiotic position parallel to the distal surface to a position perpendicular to the distal surface with one tip in close proximity to the proximal MTOC. The proximal microtubule system reaches its maximum development by the end of the tetrad stage and all micrographic evidence of it is lost in the maturation stages of late sporogenesis.
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    Morphogenesis of coremia and rhizomorphs in the AscomyceteSphaerostilbe repens (1983)
    Springer
    Protoplasma 116 (1983), S. 99-114 
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    ISSN: 1615-6102
    Keywords: Sphaerostilbe repens ; Ultrastructure ; Differentiation ; Coremia ; Rhizomorphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The differentiating stages of coremia and rhizomorphs inSphaerostilbe repens were studied by transmission electron microscopy. Vegetative mycelium is characterized by highly cytoplasmic cells rich in ribosomes and mitochondria and with few vacuoles as well as endoplasmic reticulum. Cell walls are thin attaining a maximum thickness of 0.10 μm. During the aggregating phase a prosenchymatous mass of randomly oriented cells is produced by localized elongation and branching of the filaments. The hyphae in this region have the appearance of actively metabolising cells. In the course of the differentiating phase, numerous hyphae of the median zone of the aggregate grow upward and downward to give rise to coremium and rhizomorph primordia respectively. The individual hyphal tips lay parallel to each other and cells of the growing apices retain their meristematic characteristics. At the periphery of the aggregate and to a lesser extent in the subapical rhizomorphic zone, cells reduce their cytoplasmic density as a consequence of a decrease in the number of ribosomes. These cells also increase in size and become isodiametric and vacuolated. During cellular differentiation walls increase steadily in thickness and at the elongating phase they reach 0.30 μm in the rhizomorphic cortex. Mucilaginous material is progressively deposited around hyphae and in the most differentiated zones, coalesce to fill interhyphal spaces. This extracellular matrix seems to play a role in maintaining cohesiveness of the aggregated organs. The tissue in the process of differentiation is scattered with cells highly enriched in mitochondria and with cells virtually undifferentiated. Accumulation of microfilaments takes place in the differentiating zone localized behind the immersed meristematic apex. These structures might be involved in wall synthesis. Glycogen rosettes accumulate in the vegetative mycelium surrounding the aggregating centers, suggesting the possibility of supplying energy during the differentiating processes. The vacuolar system, represented by autophagic vacuoles which are present until the differentiation phase, presumably may also participate in the biochemical changes that occur during aggregation. Coremial cells are characterized by an increase in wall thickness, a highly sinuous plasma-membrane as well as large amounts of mucilaginous compounds accumulated between hyphae, but in all other respects they resemble the cells of actively growing vegetative hyphae.
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    Ultrastructure of aerial stalk formation by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 125-135 
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    ISSN: 1615-6102
    Keywords: Ciliated protozoan ; Sorogenesis ; Extracellular matrix ; Secretion ; Extrusive organelles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sorogena stoianovitchae Bradbury andOlive is an unusual kinetophragminophoran ciliate characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises aerially from the medium surface to produce a sorocarp. A light and electron microscope study of sorogenesis revealed how the sorogenic cells produce the stalk. The feeding ciliates contain numerous subpellicular expansions of rough endoplasmic reticulum cisternae that are only one element of the secretory system necessary for stalk formation. Upon aggregation, the stalk secretory system develops further, initially with the proliferation of the subpellicular expansions. Then, during later aggregation and early sorogenesis, other secretory elements appear: stalk material vesicles, dense granule vesicles, and electron lucent vacuoles. These are all derived from the rough endoplasmic reticulum. Only the subpellicular expansions and stalk material vesicles appear to add to the stalk matrix. The dense granule vesicles could be precursors of the stalk material vesicles; the electron lucent vacuoles, which can be demonstrated to contain fibrillar material, are perhaps by-products of the secretory process. Sorogenesis inSorogena occurs by a mechanism unique among the stalk-producing protists that have been studied.
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    Stalk function during sorogenesis by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 136-144 
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    ISSN: 1615-6102
    Keywords: Stalk ; Ciliated protozoan ; Sorogenesis ; Extracellularmatrix ; Ultrastructure ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sorogenic cells of the haptorid ciliateSorogena stoianovitchae Bradbury andOlive secrete a hydrated, fibrillar matrix that becomes organized to form a stalk. This light and electron microscope study examines the role of the secreted stalk matrix in the development of the sorocarp. The stalk material is secreted as a compact clump or clumps of material that expands as it hydrates. The expanded stalk material is initially viscous, but soon, through dehydration or cross-linking, solidifies to form a sheath. The sheath is the outside layer of the stalk, provides structural support, and controls the expansion of the newly secreted stalk material. The sorogenic cells continue to secrete stalk material that expands once it is outside of the cell. The resulting expansion force is directed upward by the sheath, thereby moving the cells further above the surface. The continued dehydration of the sheath material provides an inwardly directed force that also contributes to the upward movement of the sorogen.
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    Ultrastructural demonstration of loss and recovery of cytochrome oxidase activity during and after heat induction of microcycle conidiation inNeurospora crassa (1983)
    Springer
    Protoplasma 116 (1983), S. 149-154 
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    ISSN: 1615-6102
    Keywords: Cytochrome oxidase ; Cytochemistry ; Ultrastructure ; Neurospora ; Heat treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytochrome oxidase (EC 1.9.3.1) activity of conidia of wild-typeNeurospora crassa was detected cytochemically at the ultrastructural level by 3,′-diaminobenzidine (DAB) reaction during heat treatment at 46 °C and after shift down to 25 °C. At 46 °C the decrease in the enzyme activity was shown to be time-dependent (0–10 hours) in the progressively overswelling conidia. Gradual recovery of the DAB reaction occurred in mitochondria of conidia outgrowing conidiogenous germ tubes (microcycle conidiation) when shifted down to 25 °C. Inactivation of cytochrome oxidase was efficiently prevented during heat treatment in the presence of Tween 20. Such conidia no longer overswelled but still required shift down to 25 °C to produce germ tubes with delayed conidiogenous ability.
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    URL: http://dx.doi.org/10.1007/BF01279832
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    The effect of UV-B and UV-C radiation on sugar beet leaves (1983)
    Springer
    Protoplasma 117 (1983), S. 7-16 
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    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Chloroplast ; Ultrastructure ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of UV-C (254 nm) and UV-B (290–320 nm) radiation on leaves ofBeta vulgaris L. at the ultrastructural level was investigated. Although the damage caused by UV-C radiation was more striking than that resulting from UV-B radiation, several structural changes were seen in the UV-B treated material. Generally the effects of UV-B and UV-C radiation were different, suggesting different mechanisms of action, discernible even at the ultrastructural level.
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    URL: http://dx.doi.org/10.1007/BF01281779
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    The ultrastructure of the formation and development of the amoeboid tapetum inArum italicum miller (1983)
    Springer
    Protoplasma 117 (1983), S. 116-129 
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    ISSN: 1615-6102
    Keywords: Pollen ; Amoeboid tapetum ; Arum italicum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A tapetum is found around all higher plant meiocytes and is thought to nourish them. It may, in turn, be influenced by their development. The mature tapetal membrane in amoeboid (or periplasmodial) tapeta, of whichArum italicum is an example, fits closely around the developing meiocyte. This description of tapetal ultrastructure starts from the meiotic prophase when the tapetum is still cellular and comprises two rows of cells on the inside of the tetrasporangiate anther. The radial walls of the still cellular tapetum start to dissolve during leptotene of the first meiosis. The lysis begins in the middle lamella in those areas penetrated by the most plasmodesmata. The walls in contact with the meiocytes on the other hand do not disappear until after the first meiosis. At telophase the now fused cytoplasmic tapetal mass begins to extend its joint plasmamembrane, amoeboid fashion, into the loculus. A cluster of microtubules can be seen at the apex of this intrusion apparently initiating or maintaining the shape of the invading plasmamembrane front. The tapetum now adheres closely to the microspores. The tapetal zone closest to the spores has a prominent population of microtubules and just a little ER, whereas the outer zone away from the spores contains all the other organelles. The inner zone, in a squash preparation, is not readily separated from the spores. The microtubules, at the middle microspore stage, are no longer to be seen in a circle around the microspores, but spread out with some lying orthogonal to the now-forming exine surface. In places the tapetal plasmamembrane begins to retract from the exine leaving roughly cone-shaped zones (spines) which become filled with fibrillar material. This material begins to be deposited on the exine surface. These “spines” are both PAS. and Coomassie-blue positive and susceptible to acetolysis.
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    The structure and histochemistry of sclerotia ofSclerotinia minor Jagger III. Changes in ultrastructure and loss of reserve materials during carpogenic germination (1983)
    Springer
    Protoplasma 117 (1983), S. 214-225 
    Details
    ISSN: 1615-6102
    Keywords: Histochemistry ; Sclerotia ; Sclerotial germination ; Sclerotinia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytoplasmic reserves and extracellular substances were progressively broken down and utilized during carpogenic germination of sclerotia ofSclerotinia minor. Glycogen, wall polysaccharides and polyphosphate granules were removed first from regions of the sclerotium distant from developing apothecia, while protein bodies near the base of apothecial stipes were hydrolysed before those further away. The number of profiles of mitochondria and endoplasmic reticulum in cortical and medullary hyphae increased at the onset of germination, indicating increased metabolism in the hyphae. In contrast to developing sclerotia, simple pores with Woronin bodies were frequent in walls and septa during germination. Hyphae that appeared to converge towards the base of apothecial initials retained their cytoplasm and organelles until late in germination and hydrolysis of their reserves was delayed; these are interpreted as translocatory hyphae, although further work is required to determine their role unequivocally. When apothecia were fully developed, hyphae throughout the sclerotium were empty and the walls and extracellular matrix of cortical and medullary hyphae had almost completely broken down.
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    URL: http://dx.doi.org/10.1007/BF01281825
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    Mitosis in the freshwater red algaBatrachospermum ectocarpum (1983)
    Springer
    Protoplasma 118 (1983), S. 56-70 
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    ISSN: 1615-6102
    Keywords: Carposporophyte ; Cell division ; Mitosis ; Rhodophyta ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic ultrastructure was observed in meristematic cells of carposporophyte generations of the freshwater red algaBatrachospermum ectocarpum. Prior to nuclear division, cell elongation occurs resulting in the nucleus being located at the proximal end of the cell and separated by a large central vacuole from a distal “empty region” which the daughter nucleus eventually occupies. In late prophase, nuclear envelope-attached polar rings are situated adjacent to shallow nuclear invaginations. At prometaphase the nuclear invaginations extend deeply into the nucleus forming continuous cytoplasmic channels containing microtubules. Perinuclear ER and a typical equatorial chromosomal plate are formed by metaphase at which time the nuclear envelope lining the cytoplasmic channels has dispersed. Chromosomal and non-chromosomal microtubules converge at the poles where a single, large gap is seen in the otherwise intact nuclear envelope. Polar rings were not detected in the few mitotic cells observed beyond prometaphase but are thought to be present. During anaphase an interzonal midpiece is formed and the distal-most incipient daughter nucleus moves laterally past the central vacuole into the apical “empty region”. Features of mitosis inBatrachospermum are believed to be intermediate between those exhibited by the lower and higher orders of red algae, this being consistent with the taxonomic placement of the genus in theNemaliales, the least advanced order of the classFlorideophyceae.
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    URL: http://dx.doi.org/10.1007/BF01284747
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    The ultrastructure of nuclear bodies in interphase plant cell nuclei (1983)
    Springer
    Protoplasma 118 (1983), S. 95-103 
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    ISSN: 1615-6102
    Keywords: Nuclear bodies ; Nucleolus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nuclear bodies are found in interphase nuclei of root apices of a number of plant species. They often show differences in structure and position relative to the nucleolus and this has led to an attempt to define two classes of body. However, in some species their separation into two classes on structural grounds alone breaks down, indicating that although they may occupy different positions within the nucleus they may in these particular cases be only different forms of the same body. The two extremes of the range of bodies examined represent what have been called “nucleolus-associated body” (karyosome) and “dense body”. The nucleolus-associated body is typically attached to, or adjacent to, the nucleolus. It is composed of fibrils 4–8 nm wide and often has an open structure showing compound threads or fibrils separated from each other by electron-lucent spaces. The dense body is more compact in structure and typically lies free in the nucleoplasm. Both types of body have an affinity for silver ions which, together with their staining reaction following treatment with EDTA, indicates that they consist of ribonucleoprotein. The characteristics of nuclear bodies found in different plant species have some relationship with the structure and DNA content of the interphase nucleus. Nucleolus-associated bodies are characteristic of species with an areticulate nuclear structure (2 C DNA content 〈6 pg), while dense bodies are common in species with a reticulate nuclear structure (2 C DNA content 〉6 pg). The possible functions of the two forms of nuclear body are discussed.
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    URL: http://dx.doi.org/10.1007/BF01293065
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    Ultrastructural polysaccharide localization in calcifying and naked cells of the coccolithophoridEmiliania huxleyi (1983)
    Springer
    Protoplasma 118 (1983), S. 157-168 
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    ISSN: 1615-6102
    Keywords: Calcification ; Coccolithophorids ; Polysaccharide localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Emiliania huxleyi is a marine coccolithophorid which produces coccoliths,i.e., particles consisting of calcite and macromolecular organic material. The coccoliths are formed intracellulary in specialized organelles which comprise a coccolith vesicle (CV) and a reticular body (RB), together forming the CV/RB system or calcifying system. After termination of calcification, the coccolith is extruded and incorporated into the coccosphere,i.e., one or several layers of extracellular coccoliths surrounding the cell. Apart from the coccolith-producing cells (C cells) ofE. huxleyi, there are naked cells (N cells) which seem to have lost the capacity to produce coccoliths but are very similar to the C cells in other morphological respects. Biochemical studies have revealed that polysaccharides may play a regulatory role in calcification. The aim of the present study was to determine the localization of polysaccharides in both C and N cells electron microscopically. For this purpose, a cytochemical staining technique according toThiéry (1967) was applied. The CV/RB system of C cells was conspicuously stained. Due to the excellent stainability of this system, a putative succession of morphological stages during coccolithogenesis could be described. The staining pattern of the N cells closely resembled that of the C cells. It was found, however, that the “calcifying” system of N and C cells differed in both morphology and position. It is suggested that the divergent morphology of the “calcifying” system of N cells accounts for its failure to produce coccoliths.
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    URL: http://dx.doi.org/10.1007/BF01293073
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    Some aspects of the development of the endodermis and cortex ofTilia cordata andPicea sitchensis (1983)
    Springer
    Plant and soil 71 (1983), S. 147-153 
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    ISSN: 1573-5036
    Keywords: Cortex ; Endodermis ; Picea sitchensis ; Tilia cordata ; Transfer cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The endodermis of bothTilia cordata andPicae citchensis progressess through 3 characteristic phases of development. These developments are delayed somewhat in the xylem pole endodermis ofT. cordata, while inP. sitchensis 3–5 passage cells are found. The cortex ofT. cordata is characterised by very thick walls, while that ofP. sitchensis is characterised by a thick walled layer just outside the endodermis and by 2–3 outer layers of transfer cells.
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    URL: http://dx.doi.org/10.1007/BF02182649
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    Limnological effects of peatland drainage and fertilization as reflected in the varved sediment of a deep lake (1983)
    Springer
    Hydrobiologia 106 (1983), S. 43-57 
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    ISSN: 1573-5117
    Keywords: eutrophication ; paleolimnology ; diatoms ; sediment chemistry ; peatland management
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Stratigraphy of diatoms and chemistry in the surface sediment deposited at 35 m depth in Lake Polvijärvi was studied. The existence of annual laminations or varves in the sediment allowed a precise dating of the profile. Diatoms were analysed in 0.5 cm sequences; from 0 to 16.0 cm continuously and then intermittently every fourth 0.5 cm down to 44.0 cm. Sediment chemistry (loss-on-ignition, C, N, Fe, Mn, Mg, P, chlorophyll and carotenoids) was analysed from sediment surface down to 10.5 cm of altogether 33 subsamples, each containing 1–3 varves, and spanning the period 1921–1980. From 4.5 cm depth upwards the diatom concentration strongly increases, and the plankton diatom succession from Tabellaria flocculosa through Asterionella formosa to Melosira ambigua and Fragilaria crotonensis reflects a marked eutrophication of the lake. This algal succession occurs in pace with an increase in sediment accumulation rate and changes in sediment chemistry, which indicate increased allochthonous inputs and enhanced algal production in the lake. The change of the lake ecosystem is contemporaneous with extensive peatland draining and fertilizing that was carried out on its watershed during the past two decades. Existing chemical data from a number of lakes situated within the drainage area prove that at present the treated peatlands are the main source of nutrient loading of Lake Polvijärvi. A former period with indications of slightly increased productivity of the lake was dated by varve counting to AD 1690–1910 (35–12 cm). This period (characterised by Asterionella formosa) may coincide with that of the slash-and-burn cultivation in the area.
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    Global holocene magnetostratigraphy (1983)
    Springer
    Hydrobiologia 103 (1983), S. 45-51 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; magnetism ; dating ; Australia ; North America ; Japan ; Europe ; Near East
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paleolimnomagnetic records from five regions of the world have been combined with historical magnetic field observations in order to produce regional geomagnetic master curves.
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    URL: http://dx.doi.org/10.1007/BF00028426
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    Cladoceran remains as evidence of change in trophic state in three Swiss lakes (1983)
    Springer
    Hydrobiologia 103 (1983), S. 141-146 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; lakes ; sediments ; eutrophication ; Cladocera ; Switzerland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Species composition and density of cladoceran populations changed in Lakes Zürich, St. Mortiz and Baldegg as human populations increased in these watersheds. Lake Zürich sediments became annually laminated in the 1890's as a result of increased organic input as the size of the cities surrounding the lake grew. At the same time, the Bosmina species changed from a oligotrophic form (longispina) to a eutrophic form (longirostris). An increase in Daphnia spp. populations also occurred at this time in the lake's history. Bosmina longispina reappeared in the lake in 1965 as the lake's trophic status changed from eutrophic to mesotrophic due to effective sewage treatment facilities. Annual laminations appear in the Lake St. Moritz sediments about 1910. Shortly thereafter, a shift from B. longispina to B. longirostris occurred. This change in trophic status is associated with increased tourism in the area. Lake Baldegg sediments also show annual laminations beginning in 1885 and a similar shift in the Bosmina species. Other cladoceran remains were too scarce to be useful in interpreting the histories of these lakes.
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    Mineral magnetic studies of lake sediments (1983)
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    Hydrobiologia 103 (1983), S. 37-44 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; magnetic minerals ; sediment sources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This review outlines the origin and environmental significance of magnetic minerals in lake sediments. Attention is drawn to situations where the patterns of mineral magnetic variation is a reflection of processes other than changing erosion rates and fire incidence. The use of mineral magnetic techniques in sediment source tracing, palaeoclimatic studies and the reconstruction of particulate pollution history is illustrated by means of case studies from Britain and N. America. The value of magnetic susceptibility as an on-site core logging technique is shown by reference to data from Lake Washington.
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    The use of magnetic measurements in interpreting the fire histories of lake drainage basins (1983)
    Springer
    Hydrobiologia 103 (1983), S. 53-58 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; secondary ferrimagnetic oxides ; S.I.R.M. ; magnetic susceptibility ; laminated sediments
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The magnetic parameters S.I.R.M. and magnetic susceptibility have been used to try and establish the fire histories of lake drainage basins. The technique is demonstrated using sediments from three lakes: Llyn Bychan (N. Wales), a lake with a recently burnt catchment, Lake Biscarrosse (S. W. France), a lake with a well documented fire history, and Lake Laukunlampi (E. Finland), a lake with laminated sediments and a long, but unknown fire history.
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    Changing patterns of sediment accumulation in a small lake in Scania, southern Sweden (1983)
    Springer
    Hydrobiologia 103 (1983), S. 59-64 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; sedimentation pattern ; magnetic susceptibility ; Scanian lakes ; palaeomagnetism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Magnetic susceptibility measurements have been used to correlate synchronous depths in ca. 50 l m. cores of recent sediment from a small lake (area ca. 55 ha) in Scania, southern Sweden. The three-dimensional picture of sediment accumulation which emerges provides a basis for studying sediment deposition patterns through time. Using a palaeomagnetic chronology, the results show that the pattern and rate of accumulation have dramatically altered during the past 350 years, thus making semiquantitative studies of downcore sediment properties in a single core problematical. Possible reasons for these phenomena are briefly discussed.
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    URL: http://dx.doi.org/10.1007/BF00028428
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    The use of X-ray radiographic methods in studying sedimentary properties and rates of sediment accumulation (1983)
    Springer
    Hydrobiologia 103 (1983), S. 65-69 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; X-ray radiography of sediment cores ; sedimentary properties ; sediment accumulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract X-ray radiographs of unextruded sediment cores are used for the documentation and the interpretation of primary and secondary sedimentary structures, and for the correlation of synchronous laminations between different cores. The vertical variation in bulk density, water content and void ratio, and the increase of solids with increasing sediment depth are calculated from the recorded film density along the radiographs. The X-ray radiographic technique for the study of sedimentary properties is fast and non-destructive. The technique is especially valuable when studying the uppermost part of the sediment cover and the processes of sediment redistribution and sediment accumulation. Studies are being undertaken in several Swedish lakes and coastal bays, where mono- and stereoradiographs are being used to classify bottom and sediment types, to interpret changes in the depositional environment, and to calculate past and present rates of sediment accumulation.
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    URL: http://dx.doi.org/10.1007/BF00028429
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    An automated technique for the accurate positioning of sediment core sites and the bathymetric mapping of lake basins (1983)
    Springer
    Hydrobiologia 103 (1983), S. 71-74 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; sediment core positioning ; hydrographic survey ; computer contouring ; morphometric calculation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Automated techniques for sediment core site positioning, hydrographic survey, and contour mapping are described. The computer contouring system can be extended to calculate values for morphometric variables such as maximum length (1max), maximum width (wmax), lake perimeter (10), lake area (A) and lake volume (V). The techniques are exemplified using results from Augher Lough, Northern Ireland.
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    Recent climatic changes recorded by the salinity of pore waters in the Dead Sea sediments (1983)
    Springer
    Hydrobiologia 103 (1983), S. 75-79 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; Dead Sea climate ; pore-waters ; diffusion ; sediments ; salinity ; porosity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The salinity of lakes is subject to variations imposed by climatic changes. These variations are recorded in the salinity profile of pore waters. Meromictic lakes, such as the Dead Sea, are a special case where waters which underlie the mixolimnion reflect salinity variations. In a sediment core from Dead Sea shallow waters, the salinity profile exhibited a minimum at about 1.9 m depth. It is shown by a diffusion model that this minimum can be attributed to lower salinities which prevailed at the sediment water interface for several decades around the turn of this century. No such minimum was observed in a sediment core from the deepest part of the lake where, during the last two centuries, the overlying brines had a constant salinity.
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    Trace element associations as indicators of sediment accumulation in lakes (1983)
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    Hydrobiologia 103 (1983), S. 81-84 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; geochemistry ; trace elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A geochemical study of lacustrine sediments was undertaken as part of a major paleolimnological project concerned with the impact of man on lakes. Factor analysis was applied to the geochemical data obtained from a core from one lake. Three principal factors which explained most of the variance of the initial data were identified. Factor I is related to the organic:mineral component ratio of the sediment, and can be considered as an indirect index of change in lake trophic status through time. Factor II is related to the granulometric composition of the sediment and matches evidence for changes in the hydrological regime of the lake. Factor III reflects changes in redox potential and is more closely related to processes occurring within the lake than other factors. Specific geochemical associations of elements are connected with each factor and are the factor indicators. The correlation of these associations are analyzed as geochemical indices of the variability of sediment accumulation conditions in time.
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    Interpretation of lake quality from contemporary diatom assemblages (1983)
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    Hydrobiologia 103 (1983), S. 91-97 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; assemblage indicators ; Finland
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Diatom assemblages from the topmost sediment of 49 lakes were ordinated by means of a program for detrended correspondence analysis and reciprocal averaging (Decorana). Five lake groups were separated, each having more or less characteristic diatom assemblages and water quality. Shifts from one group to another caused by factors such as acidification, artificial drainage, diffuse nutrient loading and sewage are discussed.
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    Transfer functions for estimating paleoecological conditions (pH) from East African diatoms (1983)
    Springer
    Hydrobiologia 103 (1983), S. 85-90 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; diatoms ; East Africa ; transfer functions ; pH-indicators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Our purpose is to establish the quantitative relationship between recent diatom floras and ecological parameters, in order to extrapolate the results to the past. The parameter pH is here considered as an example. This work is based on the study of about I60 diatom samples from East Africa and of their corresponding biotopes. We propose some statistical methods to interpret the data. Correspondence analysis allows us to define the pH-indicator species. The regression calculations allow pH values to be calculated using the percentage of the diatom species in a sample.
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    Bacterial decomposition of organic matter in lacustrine sediments (1983)
    Springer
    Hydrobiologia 103 (1983), S. 99-102 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; organic matter ; bacteria ; aerobic decomposition ; oxygen consumption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The investigations were carried out in lakes situated in the forest zone (Karelian Isthmus, Baltic zone, South Ural) and in the forest-steppe (South Ural) of the USSR. The lakes differ in their bioproductivity and in the intensity of their human influence. The amount of organic matter accumulating in the sediments is closely related to production and decomposition processes in the trophogenic layer. Processes of organic matter transformation were found to be most active in the uppermost sediment. The quantity of bacteria shows no correlation with the organic matter content of the sediment. Increase in organic matter, up to 70–80% of dry weight, is often accompanied by a decrease in bottom bacteria. The intensity of aerobic decomposition of the labile organic matter can be judged from the oxygen demand of the sediments. However, it is important to differentiate between chemical and biological oxidation processes. The quantity of bottom bacteria correlates closely with the value of oxygen consumption only in cases of high sediment redox potentials.
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    Relationship between sedimentary pigments and primary production: evidence from core analyses of twelve Italian lakes (1983)
    Springer
    Hydrobiologia 103 (1983), S. 103-106 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; sedimentary pigments ; primary production ; core analyses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A statistically significant correlation of the type y = axb between sedimentary plant pigments and contemporary algal primary production has been found in a study of the recent trophic evolution of twelve Italian lakes. The equation is used to assess baseline production levels in periods (50–70 years ago) when human influence was low.
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    The mythical concept of eutrophication (1983)
    Springer
    Hydrobiologia 103 (1983), S. 107-111 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; lake ontogeny ; lake succession ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Paleolimnologists frequently invoke the term ‘eutrophication’ for describing apparent enrichment phases in the history of a lake. I argue that this term is often used incorrectly and that alternative explanations can serve as more accurate descriptions. Increased organic content in the sedimentary record may result from increased nutrient availability (eutrophication), but it can also reflect decreased residence time of water, or changes in biotic interactions, or changes in lake morphometry. Additionally, I argue that ‘eutrophication’ is an inappropriate term for describing the aging process of lakes. Lake ontogeny is the preferred term, as it does not imply directional changes in nutrients, nor in community structure.
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    Eutrophication and the disappearance of lakes in the Brodnica Lake District, Northern Poland as a result of human interference (1983)
    Springer
    Hydrobiologia 103 (1983), S. 165-168 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; lakes ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Problems relating to the disappearance and eutrophication of lakes as a result of human activity are presented. A study area was selected located in an agricultural/forest region where human influence on lakes used to be minimal. In the past 25 years a number of lakes have completely disappeared and others have become rapidly enriched. Human interference has included: the pulling down of water mills, drainage and river canalisation, construction of holiday resorts, development of intensive farming, increased mineral fertilization, and the extension of roads and road traffic.
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    Zn, P and ATP in the sediments of two lakes in South Finland (1983)
    Springer
    Hydrobiologia 103 (1983), S. 177-179 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; sediment chemistry ; heavy metals ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract This investigation is concerned with the impact of industrial and municipal waste discharge on lakes near the city of Tampere, Finland. The record of P, Zn and ATP in the recent sediments of Vanajavesi I, a polluted lake, and Mallasvesi, a largely unpolluted lake, are compared.
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    An attempt to trace eutrophication in a shallow lake (Balaton, Hungary) using chironomids (1983)
    Springer
    Hydrobiologia 103 (1983), S. 169-175 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; Chironomidae ; subfossil remains ; shallow lake ; eutrophication ; Lake Balaton
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lake Balaton, the largest shallow lake in Central Europe, is about 20 000 years old. An enormous increase in tourism and the disproportionate building development of the last few decades has resulted in the acceleration of eutrophication in the lake. Widespread research to reveal the causes of water-quality deterioration and possible ways of protection against it have recently started. The investigation of the larvae of non-biting midges (Diptera: Chironomidae) in the sediment of the open-water zone has also begun. The contemporary faunal composition strongly correlates with the trophic gradient along the longitudinal axis of the lake. We therefore supposed that the eutrophication process should be identifiable from the analysis of subfossil chironomid head capsules from the upper (15 cm thick) layer of the sediment. We found that quantitative results could only be obtained when fragments as well as relatively intact head capsules are considered. Our data verify that the originally oligo-mesotrophic community has been gradually replaced by eutrophic species in a west to east direction. Large-bodied larvae belonging to the Chironomus plumosus group mix the sediment down to 15 cm as they build their tubes and consequently alter the original proportions of head capsules at the different levels. So the sequence of communities through the sediment-layers is not quite reliable.
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    URL: http://dx.doi.org/10.1007/BF00028447
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    Clostridium perfringens (Holland) as an indicator of human effluent in the sediment of Lake Tuomiojärvi, central Finland (1983)
    Springer
    Hydrobiologia 103 (1983), S. 181-184 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; Clostridium perfringens ; sewage pollution ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The horizontal and vertical distribution of the gram-positive, non-motile, spore-forming and rod-shaped bacterium Clostridium perfringens Holland was studied. The aim of the study was to estimate the quantity of C. perfringens at different depths of the sediment and evaluate the effect of human effluent which the lake received between 1940 and 1956. C. perfringens lives in the colon of man. Because it is spore forming and cannot multiply under a temperature of 20 °C and, according to the studies of Seppänen et al. (1979) it can be at least 300 years old, it may be a suitable paleolimnological indicator of pollution by human effluent. The results showed that the amounts of Clostridium increased at the same level where redox potential decreased in the sediment due to the beginning of effluent disposal at a depth of 40 mm. The maximum number of Clostridium colonies occurred between 0–30 mm depth.
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  • 97
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    Recent geologic development of Lake Michigan (U.S.A.) (1983)
    Springer
    Hydrobiologia 103 (1983), S. 193-198 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; Lake Michigan ; geochemistry ; stratigraphy ; Quaternary ; trace elements
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The stresses placed on Lake Michigan since the advent of industrialization require knowledge of the sedimentology of the whole lake in order to make informed decisions for environmental planning. Sediment accumulation rates are low: areas of the lake receiving the most sediment average only 1 mm a−1; deep-water basins average 0.1 to 0.5 mm a−1; and large areas are not receiving any sediment. Sediment was deposited rapidly (typically 5 mm a−1), in the form of rock flour, during the deglaciation of both Lake Michigan and Lake Superior Basins. Then the rate of accumulation decreased by 80–90% and has remained relatively constant since final deglaciation. Because active sedimentation occurs mostly in the deep water areas of the lake, the sediment remains undisturbed and contains a record of the chemical history of the lake.
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  • 98
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    Paleolimnological studies of annually-laminated sediments in Loe Pool, Cornwall, U.K. (1983)
    Springer
    Hydrobiologia 103 (1983), S. 185-191 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; annual laminations ; magnetism ; sediment influx ; sediment chemistry ; eutrophication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sediments of Loe Pool, a eutrophic coastal lake in south west England, consist largely of laminated clays and clay-gyttjas. Studies of the diatom microstratigraphy of frozen sediment cores from the Pool indicate that the laminations are annual, and that they contain pairs of light and dark bands formed by seasonal variations in the supply of sediment to the Pool from its catchment. Analysis of the magnetic properties of individual laminations demonstrates the presence of physical and mineralogical microstratigraphic variations, which may also be related to seasonality. A varve chronology, which is confirmed by 137Cs analysis and historical records, has been used to provide a timescale for the interpretation of data from other paleolimnological studies. A close agreement between variations in the abundance of sedimentary Sn, and the history of mining in the catchment, has been found. Similarly, analysis of total organic matter, total phosphorus, sedimentary chlorophyll a, sterols, diatoms and Cladocera in the uppermost sediments all indicate eutrophication of the Pool in the period AD 1940 to the present.
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  • 99
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    Paleolimnology of the Petén Lake district, Guatemala (1983)
    Springer
    Hydrobiologia 103 (1983), S. 205-210 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; colluvium ; soil chemistry ; clay ; phosphorus loading ; tropical lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The long-term impact of Maya culture on a lowland tropical watershed is assessed, using data from a 9.2 m sediment core taken from deep water (28 m) in Lake Quexil. Human population growth, estimated by the 1980 archaeological survey, is associated with a shift in the composition of the sediment to a dominance by inorganic material, the Maya clay formation, beginning ca. 3500 B.P. Increasing settlement densities are correlated with accelerated influxes of phosphorus, carbonates, and siliceous sediment. However, chemical data do not track short-term population fluctuations closely. Because much of the sediment is delivered as colluvium, and not by running water, there is a lag between terrestrial disturbance and impact on the aquatic system. As an indication of this lag, contemporary high sedimentation rates are a residual of Maya activity that virtually ceased some 300–400 years B.P. Comparison of the deep-water core with a shallow-water (7 m) section, based on palynological correlation, reveals only minor differences in proximate chemical composition. Chemical influxes are much higher at the deep-water site, however, as a consequence of sediment focusing in this hyperconical basin. Chemical analyses of soil samples from 21 test pits in the Quexil basin support the principal conclusion that bulk soil movement was the mode of nutrient transfer to the lake, following forest clearance by the Maya.
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    URL: http://dx.doi.org/10.1007/BF00028453
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  • 100
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    Paleolimnology of the Peten Lake district, Guatemala (1983)
    Springer
    Hydrobiologia 103 (1983), S. 199-203 
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    ISSN: 1573-5117
    Keywords: paleolimnology ; clay ; cultural disturbance ; erosion ; Guatemala ; Mayan archaeology ; silt ; particle-size analysis ; tropical lakes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Long-term changes of sedimentary particle-size distribution in two tropical lowland lakes were compared with changes of human population sizes, estimated archaeologically, in the drainage basins. Mean particle size of silt and clay fractions (〈64 µm) varied between 3 and 15 µm. High positive skewness and kurtosis of the distributions were associated with smaller particle sizes; hence small mean size resulted from greater influx of small particles while influx of larger particles was probably constant. An inverse correlation between mean particle size and human population size is interpreted to mean that disturbance-induced erosion results in delivery of very fine inorganic particles at higher rates. Within any one basin, particle-size stratigraphy is more precisely related to archaeological time periods than is pollen stratigraphy. An absolute chronology still eludes us, owing to the failure of 14C dating of calcareous, colluvial sediments, but our relative chronology is now more precise than before. If certain assumptions about past hydrologic relations can be met, particle-size analysis is a way of comparing the histories of geographically very different lakes, including lakes from tropical, temperate, and arctic regions.
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    URL: http://dx.doi.org/10.1007/BF00028452
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