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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Immunogenetics 47 (1997), S. 37-43 
    ISSN: 1432-1211
    Keywords: Key words Basques ; Algerians ; Portuguese ; Spaniards ; HLA
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  HLA-A, -B, -DRB1, -DQA1, and DQB1 alleles were studied in Iberian and Algerian populations by serology and DNA sequence methodologies. The genetic and cultural relatedness among Basques, Spaniards, and paleo-North Africans (Berbers or Tamazights) was established. Portuguese people have also maintained a certain degree of cultural and ethnic-specific characteristics since ancient times. The results of the present HLA study in Portuguese populations show that they have features in common with Basques and Spaniards from Madrid: a high frequency of the HLA-haplotypes A29-B44-DR7 (ancient western Europeans), A2-B7-DR15 (ancient Europeans and paleo-North Africans), and A1-B8-DR3 (Europeans) are found as common characteristics. Portuguese and Basques do not show the Mediterranean A33-B14-DR1 haplotype, suggesting a lower admixture with Mediterraneans; Spaniards and Algerians do have this haplotype in a relatively high frequency, indicating a more extensive Mediterranean genetic influence. The paleo-North African haplotype A30-B18-DR3 present in Basques, Algerians, and Spaniards is not found in Portuguese either. The Portuguese have a characteristic unique among world populations: a high frequency of HLA-A25-B18-DR15 and A26-B38-DR13, which may reflect a still detectable founder effect coming from ancient Portuguese, i.e., oestrimnios and conios; Basques and Algerians also show specific haplotypes, A11-B27-DR1 and A2-B35-DR11, respectively, probably showing a relatively lower degree of admixture. A neighbor-joining dendrogram place Basques, Portuguese, Spaniards, and Algerians closer to each other and more separated from other populations. Genetic, cultural, geological, and linguistic evidence also supports the hypothesis that people coming from a fertile Saharan area emigrated towards the north (southern Europe, Mesopotamia, the Mediterranean Islands, and the North African coast) when the climate changed drastically to hotter and drier ca 10 000 years B.C.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 85 (2003), S. 0 
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In this work, we investigated the role of nitric oxide (NO) in neurotoxicity triggered by α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor activation in cultured hippocampal neurons. In the presence of cyclothiazide (CTZ), short-term exposures to kainate (KA; 5 and 15 min, followed by 24-h recovery) decreased cell viability. Both NBQX and d-AP-5 decreased the neurotoxicity caused by KA plus CTZ. Long-term exposures to KA plus CTZ (24 h) resulted in increased toxicity. In short-, but not in long-term exposures, the presence of NO synthase (NOS) inhibitors (l-NAME and 7-NI) decreased the toxicity induced by KA plus CTZ. We also found that KA plus CTZ (15-min exposure) significantly increased cGMP levels. Furthermore, short-term exposures lead to decreased intracellular ATP levels, which was prevented by NBQX, d-AP-5 and NOS inhibitors. Immunoblot analysis revealed that KA induced neuronal NOS (nNOS) proteolysis, gradually lowering the levels of nNOS according to the time of exposure. Calpain, but not caspase-3 inhibitors, prevented this effect. Overall, these results show that NO is involved in the neurotoxicity caused by activation of non-desensitizing AMPA receptors, although to a limited extent, since AMPA receptor activation triggers mechanisms that lead to nNOS proteolysis by calpains, preventing a further contribution of NO to the neurotoxic process.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 4002-4004 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The mapping of surface acoustic wave (SAW) fields by means of microscopic reflectance and reflectance anisotropy in GaAs-based structures is reported. The two techniques are complementary with the second being sensitive to the strain and the first both to the strain and to the surface modulation induced by the SAW. Their combination provides information about both the longitudinal and transverse components of the SAW particle displacement vector. © 1999 American Institute of Physics.
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Munksgaard International Publishers
    ISSN: 1600-0714
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Background:  A cross-sectional study on the oral mucosal conditions among the Waimiri Atroari Indians from central Amazonia, Brazil, has been conducted. These Indians keep their traditional way of life and are free from habits such as smoking, alcohol drinking, and use of pacifiers.Methods:  Clinical examinations of a representative, randomly selected sample of patients during routine dental treatment, following ethical procedures recommended by Brazilian laws were made.Results:  Out of 922 individuals, 587 were examined, among which 52.57% of the children up to 12 years old and 73.44% of patients aged 13 years or older presented at least one oral mucosal condition. The conditions more frequently observed were, in decreasing order of prevalence: fissured tongue, focal epithelial hyperplasia (FEH), lesions of traumatic origin, geographic tongue, Fordyce's spots, and candidiasis. Only one case of leukoplakia was identified.Conclusions:  Conditions observed among theses Indians were essentially the same that have been described in other populations around the world, except for FEH, which, as a characteristic lesion of Indians, had high prevalence (20.95%). The lesions observed were related to the way of life of this specific population.
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 270 (1977), S. 501-501 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 The H2O (616-523) spectrum of NGC253. The error bars are equal to twice the standard error of the mean obtained for each channel. The continuum flux of the nucleus of NGC253 has already been removed from the spectrum obtained from observations. The H2O spectrum of NGC253 is presented in ...
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  • 6
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 66 (1989), S. 247-251 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the measurement of diffusion transport length LD, quantum efficiency φ for photoelectron generation, and the Debye screening length and associated trap density NA in an undoped Bi12SiO20 (BSO) photorefractive crystal. The method is based on the optical erasing of holographically recorded gratings in the crystal. The measurement of the diffraction efficiency evolution is considerably facilitated profitting from polarization properties of anisotropic diffraction in BSO-type crystals in a self-diffraction experiment. Data processing is carried out using simple linear regression techniques for experimental conditions in two limiting situations: far from and well into trap saturation conditions. We prove that optical erasure closely verifies the decay law predicted by theory even if a highly contrasted pattern of light is used for recording. We measured NA=6.3×1016 cm−3, agreeing in order of magnitude, with already reported values, but found out LD=0.1 μm, which is too much lower than data in literature for an electron-based charge transport material as this one.
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  • 7
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 5060-5066 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The modulation of light beams by surface acoustic waves (SAW) in periodically modulated photonic materials is investigated. The periodic modulation allows for new scattering processes which can improve the efficiency of SAW-based modulators, as proposed by P. St. J. Russell [Phys. Rev. Lett. 56, 596 (1986)]. In particular, scattering geometries with collinear propagation paths for the SAW and the light beam become possible using SAW wavelengths much larger than the light wavelength. We analyze the performance of such modulators based on semiconductor materials and examine the role of random fluctuations in structure dimensions on their operation. © 2001 American Institute of Physics.
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  • 8
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 8228-8234 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The polarization anisotropy of the photoluminescence from quasiplanar quantum wires fabricated on the sidewall of [01¯1]-oriented mesas on the (311)A GaAs surface is investigated using a modulation technique that combines high spatial (∼1 μm) and polarization resolution (〈0.1%). Due to their low symmetry, (311)A-oriented quantum wells are intrinsically anisotropic with the fundamental transition preferentially oriented along the [2¯33] direction. The anisotropy contribution from the lateral confinement in the [01¯1] wires opposes that from the vertical confinement. With increasing lateral confinement, the wire anisotropy initially reduces and then changes its sign. The lateral extent of the electronic wave functions involved in the anisotropic transitions is obtained from a comparison of the results with a theoretical model. © 1999 American Institute of Physics.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: In the present work we investigated the mechanisms controlling the release of acetylcholine (ACh) and of γ-aminobutyric acid (GABA) from cultures of amacrine-like neurons, containing a subpopulation of cells which are simultaneously GABAergic and cholinergic. We found that 81.2 ± 2.8% of the cells present in the culture were stained immunocytochemically with an antibody against choline acetyltransferase, and 38.5 ± 4.8% of the cells were stained with an antibody against GABA. Most of the cells containing GABA (87.0 ± 2.9%) were cholinergic. The release of acetylcholine and GABA was mostly Ca2+-dependent, although a significant release of [3H]GABA occurred by reversal of its transporter. Potassium evoked the Ca2+-dependent release of [3H]GABA and [3H]acetylcholine, with EC50 of 31.0 ± 1.0 mm and 21.6 ± 1.1 mm, respectively. The Ca2+-dependent release of [3H]acetylcholine was significantly inhibited by 1 μm tetrodotoxin and by low (30 nm) ω-conotoxin GVIA (ω-CgTx GVIA) concentrations, or by high (300 nm) nitrendipine (Nit) concentrations. On the contrary, the release of [14C]GABA was reduced by 30 nm nitrendipine, or by 500 nmω-CgTx GVIA, but not by this toxin at 30 nm. The release of either transmitters was unaffected by 200 nmω-Agatoxin IVA (ω-Aga IVA), a toxin that blocks P/Q-type voltage-sensitive Ca2+ channels (VSCC). The results show that Ca2+-influx through ω-CgTx GVIA-sensitive N-type VSCC and through Nit-sensitive L-type VSCC induce the release of ACh and GABA. However, the significant differences observed regarding the Ca2+ channels involved in the release of each neurotransmitter suggest that in amacrine-like neurons containing simultaneously GABA and acetylcholine the two neurotransmitters may be released in distinct regions of the cells, endowed with different populations of VSCC.
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Calcium Channel in Infarct-Induced Hypertrophied Rat Ventricle. Introduction: The present investigation was aimed at characterization of: (1) action potential parameters; and (2) L-type calcium channels in the hypertrophied ventricular tissue surviving an extensive healed myocardial infarction in the rat. Methods and Results: Myocardial infarction was produced in Wistar rats by ligation of the left coronary artery. One to 2 months later, their hearts were subjected to electrophysiologic study. The main difference in subendocardial transmembrane potentials recorded with intracellular microelectrodes was an increase in action potential duration (APD). In the left ventricle, the infarcted/sham-operated APD ratio ranged from 2.7 to 7.2, whereas in the right ventricle it ranged from 1.6 to 2.3 in different regions. When compared with control ceils, ventricular myocytes from infarcted hearts were found to be larger (P 〈 0.01) and showed a reduction (P 〈 0.05) in L-type calcium current (ICa,L) density obtained by whole cell, patch clamp (at 0 mV: 4.44 ± 0.41 in infarcted vs 8.03 ± 1.22 pA/pF in normal). The time course of decay of the currents could be fitted by two exponential functions in both normal and infarcted hearts. There was a tendency toward an increase in the time constant of the slower component of inactivation, T2, significant only at +20 mV (215 ± 25 vs 151 ± 15 msec). Conclusions: Cardiac hypertrophy of healed infarction in rats is associated with lengthening of the action potential in both ventricles. The main alteration observed in ICa,Lwas a decrease in the current density. Thus, alteration of the calcium channel is not the determinant factor of APD increase
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