Search Results - (Author, Cooperation:M. Herman)

2018-01-26

Wiley-Blackwell

0008-543X

1097-0142

Biology

Medicine

2011-10-28

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Aging/*genetics ; Autopsy ; Continental Population Groups/genetics ; Fetus/metabolism ; *Gene Expression Profiling ; Gene Expression Regulation, Developmental/*genetics ; Genome, Human/genetics ; Humans ; Polymorphism, Single Nucleotide/genetics ; Prefrontal Cortex/embryology/*growth & development/*metabolism ; Time Factors ; Transcriptome/*genetics

2012-10-30

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Astrocytes/immunology/virology ; Biomarkers ; Cell Differentiation ; Cell Lineage ; Cell Separation ; Cells, Cultured ; Central Nervous System/cytology/immunology/*pathology/virology ; Child ; Disease Susceptibility ; Encephalitis, Herpes Simplex/immunology/metabolism/pathology/virology ; Herpesvirus 1, Human/*immunology/pathogenicity ; Humans ; Immunity, Innate ; Induced Pluripotent Stem Cells/*cytology/virology ; Interferons/immunology ; Membrane Transport Proteins/deficiency/genetics ; Neural Stem Cells/immunology/virology ; Neurons/immunology/pathology/virology ; Oligodendroglia/immunology/pathology/virology ; Toll-Like Receptor 3/*deficiency/genetics

2011-06-28

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Animals ; *Biological Evolution ; Computer Simulation ; Cyanobacteria ; *Ecosystem ; Environment ; Feeding Behavior ; Genetic Fitness ; Locomotion ; Models, Biological ; Mytilus edulis/*physiology ; Population Density ; Probability ; Selection, Genetic

2013-12-07

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

*Conservation of Natural Resources/economics ; *Ecosystem ; Engineering/economics/standards ; Floods ; *Global Warming

2018-08-14

American Physical Society (APS)

1098-0121

1095-3795

Physics

Electronic structure and strongly correlated systems

1089-7550

AIP Digital Archive

Physics

The band offset parameter Qc = ΔEc/ΔEg for both GaAs/AlGaAs (lattice matched to GaAs), and GaInAs/AlInAs (lattice matched to InP) was extracted from the optical interband transition energies obtained from both triangular and parabolic quantum well shapes of various widths. The wells were grown using continuous analog compositional grading as opposed to the discrete, superlattice (digital) grading used by previous researchers. Electron beam electroreflectance (EBER) was the primary technique used to measure the interband transition energies. By combining the theoretical energies from quantum mechanical potential well calculations with EBER measured energies, it was possible to extract band offset values in a self-consistent manner. Qc values obtained were 0.658±0.009 and 0.650±0.001 for GaAs/AlGaAs and GaInAs/AlInAs, respectively. Measurements also revealed that Qc was both temperature and concentration independent within the range of composition studied.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

This paper presents a review devoted to the problem of how optical and structural properties of quantum-well heterostructures (QWH) can be correlated in detail, and how these properties may be connected with the parameters of the epitaxial growth process. It demonstrates how luminescence techniques, mainly photoluminescence (PL) and cathodoluminescence imaging (CLI), may be used for evaluation of the structural disorder on the atomic scale, which occurs at the growth surfaces creating the interfaces of the QWH. The physics of the excitonic luminescence in QWH (theory and experiment) is presented in detail in the first part of the review. This is followed by a comprehensive discussion of experimental aspects (hardware and software) of the luminescence techniques, as applied for studying QWH grown by molecular-beam epitaxy (MBE) and metalorganic vapor phase epitaxy (MOVPE). The specific features of both the epitaxial growth techniques, when used for growing QWH are presented in the next part of this review. Finally, the possibilities of application of PL and CLI to studies on growth of QWH by MBE and MOVPE are demonstrated on a couple of selected examples. The review concludes with a short discussion on possible interpretation mistakes which may occur when one applies the CLI to studies of interfaces in QWH without taking into account the basic parameters of the excitonic luminescence lines creating the CL images of the relevant interfaces.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Improved sets of data have been recorded and analyzed in order to study the bending rovibrational energy levels of C2D2, in the regions of the ν5–ν4 difference band (FIR) and of the ν5 fundamental band (IR). A matrix model is setup to deal with a Darling–Dennison coupling between sets of bending levels as well as with the usual l-type resonances. A simultaneous fit of the new data together with earlier microwave measurements produces an extended set of very accurate parameters, including for the first time in C2D2 s45 and qkt.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Thermal desorption experiments concerning Te deposits on GaAs (100) surfaces have been performed using quadrupole mass spectrometry. The results give evidence that near the GaAs surface two regions of different Te adsorption can be distinguished. The first region nearest to the substrate surface consists of Te adparticles, which are chemisorbed to the substrate reevaporating at temperatures above 510–520 °C. The adparticles of the second physisorbed region begin to desorb at 350–360 °C, which is still considerably higher than the desorption temperature of the bulk Te deposits. The approximate thicknesses of these two regions are 1–2 monolayers and 3–10 monolayers of Te, respectively.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— Non-histone chromosomal proteins (NHCP) from mouse brain at different stages of development and from adult liver and kidney of strain related mice were analyzed by SDS-polyacrylamide gel electrophoresis and were compared with the mouse teratoma, OTT-6050. The fetal, neonatal and adult brains were qualitatively similar in their NHCP profiles but had quantitative differences. The NHCP composition of the adult brain was clearly distinct from that of the liver and kidney and was dissimilar from that of the teratoma.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

—The branched-chain amino and ketoacids [i.e. l-leucine, l-isoleucine, l-valine, alpha-ketoisocaproic acid (AKICA), alpha-keto-beta-methylvaleric acid (AKBMVA) and alpha-ketoisovaleric acid (AKIVA)] were administered to mouse strain l fibroblasts in tissue culture in an attempt to study the effects of increased levels of the compounds in an in vitro system. All of these compounds are found to be elevated in the blood of patients with Maple Syrup Urine Disease (MSUD).With AKICA, l-leucine, AKIVA and AKBMVA, there was a decreased growth rate at concentrations of 10 to 30 times the levels found in Maple Syrup Urine Disease. Combined administration of the above six compounds at the maximum blood levels noted in MSUD produced a significantly decreased growth rate. Electron microscopic studies revealed numerous annulate lamellae in cells treated with AKICA and in those treated with a combination of all six MSUD compounds. AKICA-treated cells contained elevated concentrations per cell of free fatty acids, triglycerides, sterols and some classes of phospholipids. Isotope labelling experiments were performed using [U-14C] AKICA and [3H]isoleucine, which were added to l-cell suspension cultures containing various levels of unlabelled AKICA. Labelled AKICA and isoleucine were both taken up by the cells. The net uptake of isoleucine was inhibited by AKICA in concentrations found in MSUD. Folch-Lees extraction of cells treated with labelled AKICA revealed increased 14C counts only in the lower lipid phase.The growth inhibition and annulate lamellae observed with AKICA treatment may be due to an arrest of the cells in phase G1 of the cell growth cycle, possibly due to decreased isoleucine uptake. It is proposed that a similarly-mediated arrest in the proliferation of oligodendroglial cells during the critical period of myelination gliosis might account for the myelination abnormalities reported in MSUD.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— The effects of altered osmolarity on respiration and fine structure were compared in isolated rat cerebral versus liver mitochondria.Polarographic study of cerebral mitochondria in hypo-osmolar media showed inhibition of State 3 (ADP-dependent) respiration which was not reversed by dinitrophenol. In hyperosmolar media, State 3 respiration was transiently inhibited and State 4 (ADP-independent) respiration increased with the NAD-linked substrate pair, glutamate and malate. With succinate as substrate, respiration was not affected by moderate hyperosmolarity. In the most hyperosmolar medium, State 3 respiration was inhibited with both substrates.In contrast to the results with cerebral mitochondria, State 4 respiration was increased in hypo-osmolar media and State 3 respiration was persistently inhibited in hyperosmolar media in liver mitochondria with both substrates.In both cerebral and liver mitochondria, cytochrome c oxidase (EC 1.9.3.1.) activity was mildly inhibited in hypo-osmolar media and increased in hyperosmolar media.Electron microscopy showed that liver mitochondria were swollen in hypo-osmolar media and condensed in hyperosmolar media. Cerebral mitochondria showed mild rarefaction in hypo-osmolar media and, in hyperosmolar media, more than half the mitochondria showed either no or minimal changes in fine structure.Our results suggest that there are differences in metabolic control and structure between mitochondria from different cell types, which may be important in the cellular metabolic response to pathologic changes in water or osmolarity.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Electronic Resource

1468-2982

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

The serotonin receptor agonist m-chlorophenylpiperazine (m-CPP) stimulates the release of cortisol and prolactin, and induces migraine-like headaches. We have studied the neuroendocrine and headache responses to m-CPP in 8 subjects with migraine and l0 normal subjects. Each subject underwent two challenge tests, one with 0.25 mg/kg PO of m-CPP and the other with placebo, administered in a double-blind crossover format. Serial measurements of serum cortisol, prolactin, and m-CPP levels were made at 30-min intervals for 210 min following ingestion of the medication. The incidence and severity of headache was assessed by a structured telephone interview after each test. We confirmed that m-CPP stimulates the release of cortisol and prolactin, and may induce headache, in both migraine subjects and normal controls. The cortisol response as well as ratings of headache severity and duration directly correlated with plasma levels of m-CPP. There were highly significant associations between the cortisol response and both headache severity and duration, independent of m-CPP plasma levels. We did not find statistically significant differences between the migraine and normal subjects in terms of their neuroendocrine or headache responses to m-CPP.

Electronic Resource

1467-923X

Blackwell Publishing Journal Backfiles 1879-2005

Political Science

Electronic Resource

1077-3118

AIP Digital Archive

Physics

The experimental procedure and the results of in situ determination of growth temperatures, refractive indices at growth temperatures, and thicknesses of ZnTe, cubic MnTe, and CdTe thin films grown by molecular beam epitaxy (MBE) are reported. Visible laser interferometry with He-Ne laser 0.6328-μm light has been applied in the performed experiments. A 290-μm-thick plane-parallel GaP wafer polished to an optical finish on both sides has been used as a growth temperature calibration standard. The exemplary substrate temperature calibration curves, as well as the data gained at dynamic thermal conditions are presented and discussed. The following numerical values concerning refractive indices n at elevated temperatures have been evaluated from experimental data for the MBE grown films: n (286 °C)ZnTe=2.51, n (175 °C)ZnTe=2.49, n(286 °C)cubic MnTe=3.26, and the extinction coefficient k (286 °C)CdTe=0.23.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

We have developed a Ti:Sa autoscan laser spectrometer and used it to perform a detailed investigation of individual line profiles in the ν1+3ν3 band of 12C2H2. Pressure self-broadening effects were measured for most lines with J″ values ranging from 0 to 22, and for pressures between 10 and 600 Torr. The high-pressure data points (p〉250 Torr) are fitted satisfactorily by a Voigt profile. Line narrowing, characterized by an underestimation of the Lorentz contribution to the Voigt profile, was observed for the low pressures range (p〈150 Torr), indicating the influence of molecular confinement. The two usual limit models (soft and hard collisions) were fitted to the observed line shapes in order to extract more precise information concerning the pressure broadening. The present results confirm the absence of strong vibrational dependence in the self-broadening coefficients. Absolute line intensities are also determined in the fitting procedure. No significant differences were found for the two pressure domains if the appropriate model in each range is used. © 1999 American Institute of Physics.

Electronic Resource