ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 4 (1871), S. 245-248 
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Mathematische Annalen 47 (1896), S. 564-572 
    ISSN: 1432-1807
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European biophysics journal 7 (1980), S. 17-40 
    ISSN: 1432-1017
    Keywords: Muscle thermodynamics ; Stiffness ; Electrostatic force ; Van der Waals force swelling ; Polyvinylpyrrolidone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The elastic behavior of mechanically skinned skeletal muscle fibers in relaxing solution is modelled using equations developed by Flory (1953) for the elasticity of non-biological polymers. Mechanically, the relaxed skinned fiber is considered to be a semi-crystalline network of inextensible polymer chains, which are periodically cross-linked and which are bathed in an aqueous medium. We consider (1) configurational elastic forces in the network, (2) entropic forces due to mixing of polymer and water, (3) electrostatic forces due to fixed charges on the muscle proteins and mobile charges in the bathing solution, and (4) compressive forces due to large colloids in the bathing solution. Van der Waals forces are not considered since calculations show that they are probably negligible under our conditions. We derive an expression which relates known quantities (ionic strength, osmotic compressive pressure, and fiber width), experimentally estimated quantities (fixed charge density and volume fraction of muscle proteins), and derived quantities (concentration of cross-links and a parameter reflecting the interaction energy between protein and water). The model was tested by comparison with observed changes in skinned fiber width under a variety of experimental conditions which included changes in osmotic compressive pressure, pH, sarcomere length, and ionic strength. Over a wide range of compressive pressure (0–36 atm) the theory predicted the nonlinear relation between fiber width and logarithm of pressure. The direction and magnitude of the decrease in width when pH was decreased to 4 could be modelled asssuming the fixed charge density on the protein network was 0.34 moles of electrons per liter protein, a value in accordance with the estimates of others. The relation between width and sarcomere length over the complete range of compressive pressures could be modelled with the assumption that the number of cross-links increases somewhat with sarcomere length. Changes of width with ionic strength were modelled assuming that increasing salt concentration both increased the electrostatic shielding of fixed charges and decreased the number of cross-links. The decrease of fiber width in 1% glutaraldehyde was modelled by assuming that the concentration of crosslinks increased by some 10%. The theory predicted the order of magnitude but not the detailed shape of the passive tension-length relation which may indicate that, as with non-biological polymers, the theory does not adequately describe the behavior of semi-crystalline networks at high degrees of deformation. In summary, the theory provides a semiquantitative approach to an understanding of the nature and relative magnitudes of the forces underlying the mechanical behavior of relaxed skinned fibers. It indicates, for instance, that when fibers are returned to near their in vivo size with 3% PVP, the forces in order of their importance are: ¦ elastic forces ¦ ∼ ¦ entropic forces 〉 ¦ electrostatic forces ¦ ∼ ¦ osmotic compressive forces ¦.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Naturwissenschaften 45 (1958), S. 364-364 
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Zusammenfassung Es wird ein phänotypisch normaler 22jähriger Mann mit der Geschlechtschromosomenkonstitution 45,X/45,X,ace+(?Yq-) und einer atypischen endogenen Depression beschrieben. Die Chromosomenaberration und die Depression stehen sehr wahrscheinlich in keinem ätiologischen Zusammenhang. Der Patient zeigte keine körperlichen Veränderungen im Sinne der männlichen Turner-Phänotype, mit Ausnahme von Kleinwuchs. Seine Persönlichkeitsentwicklung jedoch ließ sich in mehreren Punkten mit den Charakteristika, wie man sie bei Frauen mit Turner-Syndrom und der Karyotype 45,X sieht, vergleichen; und er hatte einige dermatoglyphische Zeichen, ähnlich wie bei Frauen mit Turner-Syndrom. Die cytogenetischen Untersuchungsergebnisse sowohl an Leukocyten als auch an Fibroblastenkulturen deuteten an, daß das kleine azentrische Chromosomenfragment, welches sich in ungefähr der Hälfte der Zellen fand, von den kurzen Armen des Y-Chromosoms gebildet wurde. Der Fund von lediglich den kurzen Armen des Y-Chromosoms in ungefähr der Hälfte der Zellen bei einem phänotypisch normalen Mann mit normaler Testisgröße unterstützt die Vermutungen vorangegangener Untersuchungen, daß die Gene, die für die Entwicklung der Testis notwendig sind, auf den kurzen Armen des Y-Chromosoms lokalisiert sind. Das Ergebnis der Untersuchung deutet weiterhin an, wenn homologe Genloci für die kurzen Arme X im Y-Chromosom vorhanden sind, diese auf den kurzen Armen lokalisiert sein müssen und daß eine Deletion der langen Arme des Y-Chromosoms sehr wahrscheinlich kein ätiologischer Faktor in der Entwicklung der sogenannten männlichen Turner-Phänotype ist.
    Notes: Summary A phenotypical normal 22-year-old male with the sex chromosome constitution 45,X/45,X,ace+(?Yq-) and an atypical endogenous depression has been studied. The chromosome aberration and the depression are most probably not aetiologically connected. The patient presented no physical signs of male Turner phenotype, except for short stature. His personality development was, however, in several ways similar to what is characteristic for females with Turner's syndrome and karyotype 45,X and he had some dermatoglyphic signs similar to females with Turner's syndrome. The cytogenetic findings in leucocytes as well as fibroblast cultures indicated that the small acentric chromosome fragment found in approximately half of the cells was made up of the short arms of a Y chromosome. The finding of only short arms Y chromosome in approximately half of the cells in a phenotypically normal male with testes of normal size supports indications from previous studies that the genes necessary for the development of testes are located in the short arms Y. The finding further indicates that if homologous gene loci for the short arms X are present in the Y chromosome, they must be located in the short arms, and deletion long arms Y is most probably not an aetiological factor in the development of the so-called male Turner phenotype.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    New forests 6 (1992), S. 95-124 
    ISSN: 1573-5095
    Keywords: allozyme ; electrophoresis ; life history characteristics ; polymorphic loci ; population genetics ; trees
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The plant allozyme literature was reviewed to: (1) compare genetic diversity in long-lived woody species with species representing other life forms, and (2) to investigate whether the levels and distribution of genetic diversity in woody species are related to life history and ecological characteristics. Data from 322 woody taxa were used to measure genetic diversity within species, and within and among populations of species. Woody species maintain more variation within species and within populations than species with other life forms but have less variation among populations. Woody species with large geographic ranges, outcrossing breeding systems, and wind or animal-ingested seed dispersal have more genetic diversity within species and populations but less variation among populations than woody species with other combinations of traits. Although life history and ecological traits explain a significant proportion (34%) of the variation among species for the genetic parameters measured, a large proportion of the interspecific variation is unexplained. The specific evolutionary history of each species must play an important role in determining the level and distribution of genetic diversity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of muscle research and cell motility 16 (1995), S. 1-10 
    ISSN: 1573-2657
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 2,3-butanedione 2-monoxime (BDM, 3–30 mm) decreased twitch force of intact ventricular trabeculae isolated from 19-day embryonic chick hearts in a dose-dependent manner. The responses to BDM were rapid and reversible. In an attempt to determine the cellular basis for the inhibitory effect of BDM, experiments were carried out on skinned muscle fibres and isolated myocytes. In trabeculae skinned with Triton X-100, BDM depressed maximum calcium activated force (Fmax) with an IC50 of 14 mm. At 3 mm BDM, the proportional decrease in twitch force in intact tissue was similar to that of Fmax in skinned tissue. At higher BDM concentrations (10 and 30 mm), however, the proportional decrease in twitch force was greater than that of Fmax. BDM (up to 10 mm) had no effect on the normalized force-pCa relationship. In saponin-skinned preparations, BDM (3 and 30 mm) released calcium from the fully loaded sarcoplasmic reticulum to a slightly greater extent in the absence of calcium (pCa 8.5) than in the presence of a fixed level of free calcium (pCa 5.5). Whole cell patch clamping of freshly isolated chick myocytes demonstrated that BDM caused a dose-dependent decrease in the T-and L-type calcium current. Therefore, at low BDM concentrations (3 mm), the decrease in twitch force can be ascribed predominantly to depression of the contractile apparatus while, at higher concentrations of BDM, there is an additional inhibitory effect of BDM on excitation-contraction coupling.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of muscle research and cell motility 20 (1999), S. 199-209 
    ISSN: 1573-2657
    Keywords: concentration ; diffusion coefficient ; frog ; muscle ; parvalbumin ; water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The concentrations and diffusivity of two isoforms of parvalbumin, IVa and IVb, were measured using quantitative SDS PAGE in single fibers from semitendinosus muscles of the frog Rana temporaria. The concentrations of IVa and IVb were 2.9 ± 0.3 (SEM) and 4.5 ± 0.5 gl−1 total fiber volume, respectively. The total concentration of parvalbumin (7.4 ± 0.8 gl−1 total fiber) corresponds to a cytosolic concentration of 0.9 ± 0.1 mmoll−1 myoplasmic water. Estimates for the transverse and longitudinal diffusion coefficients for parvalbumin at 4°C were obtained in two ways: (1) by diffusion of parvalbumin out of skinned fibers into droplets of relaxing solution, and (2) by diffusion of parvalbumin between two juxtaposed skinned fibers under oil. The transverse diffusion coefficient obtained using the droplet method was significantly lower than that obtained using juxtaposed fibers, but the longitudinal diffusion coefficients obtained from both methods were similar. The juxtaposed fiber method more accurately approximates parvalbumin diffusion in undisturbed myoplasm because no artificial solutions were used and, upon fiber-to-fiber contact, a potentially confounding oil barrier at the interface rapidly disperses. The juxtaposed fiber method yielded values for transverse (4.27 ± 0.87 × 10−7 cm2 s−1) and longitudinal (3.20 ± 0.74 × 10−7 cm2 s−1) diffusion coefficients that were not significantly different, suggesting that diffusion of parvalbumin in myoplasm is essentially isotropic. The average diffusion coefficient of frog parvalbumin in myoplasm (3.74 ± 0.81 × 10−7 cm2 s−1; 4°C) is approximately a third of that estimated for frog parvalbumin diffusing in bulk water into and out of 3% agarose cylinders (10.6 × 10−7 cm2 s−1; 4°C). The reduced translational mobility of parvalbumin in myoplasm reflects an elevated effective viscosity due to tortuosity and viscous drag imposed by the fixed proteins of the cytomatrix and the numerous diffusible particles of the cytosol.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Journal of consumer policy 23 (2000), S. 79-105 
    ISSN: 1573-0700
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract The paper argues that environmental law can learn from consumer law as far as standing is concerned. Valuable guidance can be given to both individual and collective action. Consumer law rests on a well-founded concept of a double-track procedural system of complementary individual and collective enforcement that has undergone a considerable development over the years. With special reference to the European Court of Justice decision C-321/95 P (Greenpeace International and 18 Others v. Commission) of 2 April 1998, three arguments are put forward. Firstly, environmental law may learn from consumer law by adopting the EC approach to confer direct effect to secondary law. This empowers the individual with respect to environmental as well as participatory ends. Secondly, environmental law may espouse modern approaches with respect to the standing of associations. Thirdly, theories of judicial review need to be rethought, taking into account the new conflicts that emerge from EC integration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Biodiversity and conservation 5 (1996), S. 461-471 
    ISSN: 1572-9710
    Keywords: Liatris helleri ; genetic diversity ; allozymes ; endangered
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Liatris helleri (Asteraceae) is an insect-pollinated herbaceous perennial endemic to several high-elevation sites in the Blue Ridge Mountains of North Carolina. Allozymes were used to describe the genetic diversity and population structure in nine populations of this rare, federally listed species. Differences in leaf morphology were also examined for greenhouse-grown plants representing several populations. The proportion of the total genetic diversity found among populations, as indicated by the allozyme data, was 16%. Higher levels of population differentiation were found for differences in leaf shape; population of origin accounted for 37% of the variation in maximum leaf width, while families within populations accounted for 7%. In contrast to many endemic species, L. helleri maintains fairly high levels of genetic diversity. For the species, the percent polymorphic loci was 87.5, the average number of alleles at variable loci was 3.00 and the gene diversity was 0.276. Mean population values were percent polymorphic loci =58.4, mean number of alleles per polymorphic locus =2.59 and gene diversity =0.219. The estimated gene flow was low (Nm=0.85–1.32) and a relatively high correlation (r=0.55; p〈0.005) was found between linear geographic and genetic distance. This suggests that the populations are partially isolated by distance, despite the limited range (〈60 km) of the species. We recommend that population distinetiveness be maintained in restoration efforts.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...