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  • Ultrastructure  (43)
  • NDE  (21)
  • healthy volunteers  (17)
  • Biomagnetism (including magnetocardiography)  (16)
  • Springer  (97)
  • Annual Reviews
  • Elsevier
  • 1980-1984  (97)
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  • Springer  (97)
  • Annual Reviews
  • Elsevier
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  • 1
    Electronic Resource
    Electronic Resource
    Ultrastructure of the sperms ofPlumbago zeylanica (1981)
    Springer
    Protoplasma 107 (1981), S. 85-107 
    Details
    ISSN: 1615-6102
    Keywords: Male cytoplasmic inheritance ; Plumbago ; Pollen grain ; Pollen tube ; Sperm ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Male gametes ofPlumbago zeylanica were examined in pollen grains and tubes using light and electron microscopy of chemically and physically fixed tissues, and Nomarski interference microscopy of isolated, living sperm cells. Male gametes are elongate, spindleshaped cells containing a nucleus, mitochondria, ER, ribosomes, vesicles, dictyosomes, probable microfilaments, and a variable number of plastids. In mature pollen grains ofP. zeylanica, the two sperm cells are directly linked; they share a transverse cell wall with plasmodesmata and are enclosed together by the inner vegetative cell plasma membrane. One of these two sperms is also associated with the vegetative nucleus as a consistent feature of pollen grain organization. The basis of this association appears to be a long, narrow projection of the sperm cell (averaging 〈 1 μm wide and about 30 μm long) which wraps around the periphery of the vegetative nucleus and occupies embayments of that nucleus. This association is maintained throughout pollen tube growth but becomes less extensive near the completion of tube growth and is severed following tube discharge. The consistent occurrence of the sperm-vegetative nucleus association in pollen grains, tubes and isolated pollen cytoplasm suggests that the two structures may be directly connected, but attempts to visualize this type of connection were unsuccessful. Possibly, the entwining nature and extent of complementary interfaces between vegetative nucleus and sperm may have a role in stabilizing their association. Functionally, the two sperms and vegetative nucleus appear to travel as a linked unit within the pollen tube, possibly increasing the effectiveness of gamete delivery and helping to ensure nearly simultaneous transmission of sperms into the receptive megagametophyte.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01275610
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  • 2
    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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  • 3
    Electronic Resource
    Electronic Resource
    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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  • 4
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455949
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  • 5
    Electronic Resource
    Electronic Resource
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455929
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  • 6
    Electronic Resource
    Electronic Resource
    Influence of alaproclate on antipyrine metabolite formation in man (1984)
    Springer
    European journal of clinical pharmacology 27 (1984), S. 447-452 
    Details
    ISSN: 1432-1041
    Keywords: alaproclate ; antipyrine clearance ; serotonin reuptake inhibitor ; healthy volunteers ; antipyrine metabolism ; metabolite clearance ; alaproclate kinetics ; inhibition of drug metabolism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Alaproclate, a selective serotonin reuptake inhibitor, presently undergoing clinical trial for the treatment of major depressive disorders, has been shown to inhibit hexobarbital metabolism in mice. In the present study the influence of oral alaproclate on the total plasma clearance of antipyrine and on the formation of its metabolites was investigated in 10 healthy volunteers. The peak level of alaproclate was reached after about 1.5 h, and after a distribution phase, its plasma elimination half-life was between 3.0 and 3.5 h. Antipyrine tests were performed before treatment, during the first four doses and after the seventh dose of alaproclate 200 mg/day. During treatment, total plasma antipyrine clearance and the clearance for production of all antipyrine metabolites were reduced by 30%, indicating non-selective inhibition of oxidative drug-metabolizing enzyme activity in man by alaproclate. After the last dose of alaproclate, antipyrine plasma clearance and the clearance to its metabolites returned to control values. In order to allow more detailed evaluation of the results, the time course of the clearances for production of metabolites was investigated. This revealed that the extent of inhibition of metabolite formation by alaproclate was dependent on the plasma alaproclate level, indicating a rapidly reversible inhibition.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00549593
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  • 7
    Electronic Resource
    Electronic Resource
    Studies of the different metabolic pathways of antipyrine in man (1982)
    Springer
    European journal of clinical pharmacology 21 (1982), S. 433-441 
    Details
    ISSN: 1432-1041
    Keywords: antipyrine ; antipyrine metabolites ; drug metabolism ; route of administration ; healthy volunteers ; urinary excretion ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of antipyrine in plasma and saliva, and urinary excretion of its major metabolites, were studied following i.v. and oral administration of antipyrine 500 mg to 6 healthy volunteers. Data from both plasma and saliva showed that the oral bioavailability of antipyrine given as an aqueous solution was complete. The saliva/plasma concentration ratio was constant with time from about 3 h onwards, with a mean value of 0.87 after oral and 0.91 after i.v. administration. It is concluded that the pharmacokinetic parameters of antipyrine can be satisfactorily established on the basis of salivary data, although the volume of distribution and clearance values are then slightly too high. After i.v. administration, 3.8±1.9% of the dose was excreted in urine as unchanged antipyrine in 48h, 24.9±6.3% as 4-hydroxyantipyrine, 16.5±3.2% as norantipyrine, 13.0±2.2% as 3-hydroxymethyl-antipyrine and 5.8±1.0% as 3-carboxy-antipyrine. No significant differences were observed following oral administration. The half-lives calculated from the linear part of the urinary excretion rate curves of the metabolites were about the same for oral and i.v. administration, and were of the same order of magnitude as the elimination half-life of parent drug in plasma and saliva. It is important for determination of the ultimate metabolite ratio that urine is collected for at least 36h, because there is a delay in the excretion of 3-hydroxymethyl-antipyrine in urine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00542332
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  • 8
    Electronic Resource
    Electronic Resource
    Ultrastructure of the cyanobacterium,Mastigocladus laminosus (1982)
    Springer
    Archives of microbiology 133 (1982), S. 11-19 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Mastigocladus laminosus ; Fischerella ; True branching
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The morphology and ultrastructure of the thermophilic cyanobacteriumMastigocladus laminosus were examined by scanning and transmission electron microscopy. Mature cultures consisted of relatively old, wide filaments that branched frequently to form younger, thinner filaments. The cells of the younger filaments had a consistently cylindrical morphology, while those of older filaments were rounded and pleomorphic. The internal ultrastructure of the cells depended somewhat on their age. As young cells became larger and wider, their thylakoids underwent slight rearrangement and spread out toward the center of the cytoplasm. Polyphosphate bodies, carboxysomes (polyhedral bodies), and lipid-body-like structures increased in number as the cells aged, but ribosomes and cyanophycin granules were depleted. Cell division involved septum formation followed by ingrowth of the outer membrane and sheath. Cells in older filaments were separated from each other by a complete layer of sheath material. Septum formation in older cells was also seen to occur parallel to the long axis of the filament, thereby confirming that true branching took place.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00943762
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  • 9
    Electronic Resource
    Electronic Resource
    The effects of nitrogen limitation on the ultrastructure of the cyanobacterium Agmenellum quadruplicatum (1981)
    Springer
    Archives of microbiology 130 (1981), S. 204-212 
    Details
    ISSN: 1432-072X
    Keywords: Agmenellum quadruplicatum ; Nitrogen starvation ; Ultrastructure ; PATO poststain ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of nitrogen limitation on the ultrastructure of the unicellular cyanobacterium, Agmenellum quadruplicatum, were studied by thin sectioning transmission electron microscopy. Nitrogen became limiting for growth 14–15 h after transfer to nitrogen-limiting medium, but cultures retained full viability for at least 45 h. The c-phycocyanin: chlorophyll a ratio and cellular nitrogen content of the culture dropped rapidly after 14–15 h, as a progressive deterioration of major cell structures took place. Phycobilisomes were degraded first, followed by ribosomes and, then, thylakoid membranes. These structures were virtually depleted from the cells within 26 h. Intracellular polysaccharide accumulated in place of the normal cell structures throughout this period. Nitrogen limitation did not affect polyphosphate bodies, carboxysomes, lipid granules, the cell envelope, or the extra-cellular glycocalyx. All of the ultrastructural changes resulting from nitrogen limitation were reversed upon addition of nitrate to a starved culture. Most cell structures were restored within 3 h, and restoration was complete within 9 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00459520
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  • 10
    Electronic Resource
    Electronic Resource
    The influence of skin depth on crack measurement by the ac field technique (1982)
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 65-76 
    Details
    ISSN: 1573-4862
    Keywords: crack measurement ; ac field technique ; arbitrary skin depth ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract A general solution is given to describe the ac field around surface-breaking cracks for arbitrary values of the ratio of skin depth δ to crack depthd. This solution allows accurate interpretation of crack depth from voltage readings taken by a Crack Microgauge instrument in cases where δ andd are comparable. It is shown to agree with asymptotic formulae obtained for the cases where δ/d is very small and very large. Provided that the probe length Δ is large compared with δ, the calculations show that a very good approximation to the crack depth may be obtained, irrespective of the ratio δ/d, by using the thin-skin asymptotic formula $$d = \frac{1}{2}\Delta (V_2 - V_1 )/V_1 $$ whereV 1 andV 2 are probe voltages registered at positions just off and across the crack, respectively. The problem is solved for a crack of infinite aspect ratio which has no opening, but it can be applied with confidence at the centerline of cracks of fairly large aspect ratio.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00568962
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