Search Results - (Author, Cooperation:S. Nathan)

2018-05-10

Nature Publishing Group (NPG)

2045-2322

Natural Sciences in General

2011-11-15

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Amino Acid Motifs ; Animals ; Bacterial Proteins/*chemistry/genetics/metabolism/*toxicity ; Bacterial Toxins/*chemistry/genetics/metabolism/*toxicity ; Burkholderia pseudomallei/*chemistry/*pathogenicity ; Catalytic Domain ; Cell Line ; Crystallography, X-Ray ; Cytotoxins/chemistry/genetics/metabolism/toxicity ; Escherichia coli Proteins/chemistry ; Eukaryotic Initiation Factor-4A/*antagonists & inhibitors/metabolism ; Glutamine/metabolism ; Humans ; Mice ; Mice, Inbred BALB C ; Models, Molecular ; Mutant Proteins/toxicity ; Peptide Chain Initiation, Translational/drug effects ; Protein Binding ; Protein Conformation ; Protein Structure, Secondary ; Protein Structure, Tertiary

article

2008

Ausbildung ; Führungskraft

SAM advanced management journal, Bd. 73 (2008) H. 1, S. 10-19, 62-63, 0001-8643

0036-0805

0749-7075

English

article

2012

Rhetorik ; Coaching ; Führungskraft ; Student ; USA

The journal of management development, Bd. 31 (2012) H. 8, S. 826-844, 0262-1711

1758-7492

English

2018-02-22

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

2018-06-09

American Physical Society (APS)

0031-9007

1079-7114

Physics

Condensed Matter: Electronic Properties, etc.

2018-09-18

American Physical Society (APS)

1539-3755

1550-2376

Physics

Nonlinear Dynamics and Chaos

2018-05-17

American Chemical Society (ACS)

0002-7863

1520-5126

Chemistry and Pharmacology

2018-02-14

Wiley-Blackwell

1053-1807

1522-2586

Medicine

2018-10-16

Institute of Physics (IOP)

1748-9318

1748-9326

Biology

Energy, Environment Protection, Nuclear Power Engineering

1089-7550

AIP Digital Archive

Physics

The effects of shallow impurity and interface roughness on resonant Raman scattering by interface phonons in GaAs-AlAs multiple quantum-well structures have been studied. By correlating the Raman results with observations by high-resolution electron microscopy, it has been demonstrated that Raman scattering from interface phonons depends strongly on the sample quality. For a relatively smooth interface with about 1–2 monolayers of interface roughness, the Raman signal is governed primarily by the impurity if the impurity concentration inside the GaAs layers is greater than about 2×1016 cm−3. On the other hand, for nominally undoped quantum-well structures, the Raman signal can be dominated by interface roughness if the interfaces are sufficiently distorted.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Steady-state photoluminescence, time-resolved photoluminescence, and x-ray photoelectron spectroscopy have been used to study the electrical and chemical properties of GaAs surfaces exposed to inorganic and organic sulfur donors. Despite a wide variation in S2−(aq) concentration, variation of the pH of aqueous HS−solutions had a small effect on the steady-state n-type GaAs photoluminescence intensity, with surfaces exposed to pH=8, 0.1-M HS−(aq) solutions displaying comparable luminescence intensity relative to those treated with pH=14, 1.0-M Na2S⋅9H2O(aq). Organic thiols (R-SH, where R=−CH2CH2SH or −C6H4Cl) dissolved in nonaqueous solvents were found to effect increases in steady-state luminescence yields and in time-resolved luminescence decay lifetimes of (100)-oriented GaAs. X-ray photoelectron spectroscopy showed that exposure of GaAs surfaces to these organic systems yielded thiols bound to the GaAs surface, but such exposure did not remove excess elemental As and did not form a detectable As2S3 overlayer on the GaAs. These results imply that complete removal of As0 or formation of monolayers of As2S3 is not necessary to effect a reduction in the recombination rate at etched GaAs surfaces. Other compounds that do not contain sulfur but that are strong Lewis bases, such as methoxide ion, also improved the GaAs steady-state photoluminescence intensity. These results demonstrate that a general class of electron-donating reagents can be used to reduce nonradiative recombination at GaAs surfaces, and also imply that prior models focusing on the formation of monolayer coverages of As2S3 and Ga2S3 are not adequate to describe the passivating behavior of this class of reagents. The time-resolved, high level injection experiments clearly demonstrate that a shift in the equilibrium surface Fermi-level energy is not sufficient to explain the luminescence intensity changes, and confirm that HS− and thiol-based reagents induce substantial reductions in the surface recombination velocity through a change in the GaAs surface state recombination rate.

Electronic Resource

1540-8191

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract  Objectives: The aim of this report is to describe the rationale of our surgical approach, to explore the best management for complete atrioventricular septal defect associated with the tetralogy of Fallot (CAVSD-TOF), and to present our outcome in relation to the previously reported series. Materials and Methods: Between January 1990 and January 2002, 17 consecutive children with CAVSD-TOF underwent complete correction. Nine patients (53%) underwent previous palliation. Mean age at repair was 2.9 ± 1.9 years. Mean gradient across the right ventricular outflow tract was 63 ± 16 mmHg. All children underwent closure of septal defect with a one-patch technique, employing autologous pericardial patch. Maximal tissue was preserved for LAVV reconstruction by making these incisions along the RV aspect of the ventricular septal crest. LAVV annuloplasty was performed in 10 (59%) patients. Six patients (35%) required a transannular patch. Results: Three (17.6%) hospital deaths occurred in this series. Causes of death included progressive heart failure in two patients and multiple organ failure in the other patient. Two patients required mediastinal exploration due to significant bleeding. Dysrhythmias were identified in 4 of 11 patients undergoing a right ventriculotomy versus none of the patients undergoing a transatrial transpulmonary approach (p = ns). The mean intensive care unit stay was 3.2 ± 2.4 days. Two patients required late reoperation due to severe LAVV regurgitation at 8.5 and 21 months, respectively, after the intracardiac complete repair. The mean follow-up time was 36 ± 34 months. All patients survived and are in NYHA functional class I or II. The LAVV regurgitation grade at follow-up was significantly lower than soon after operation, 1.1 ± 0.4 versus 1.7 ± 0.5 (p = 0.002). At follow-up, the mean gradient across the right ventricular outflow tract was 17 ± 6 mmHg, significantly lower than preoperatively (p 〈 0.001). Conclusions: Complete repair in patients with CAVSD-TOF seems to offer acceptable early and mid-term outcome in terms of mortality, morbidity, and reoperation rate. Palliation prior to complete repair may be reserved in specific cases presenting small pulmonary arteries or severely cyanotic neonates. The RVOT should be managed in the same fashion as for isolated TOF; however, a transatrial transpulmonary approach is our approach of choice. (J Card Surg 2004;19:175-183)

Electronic Resource

1551-2916

Blackwell Publishing Journal Backfiles 1879-2005

Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Physics

The YO1.5–ZrO2 system consists of five solid solutions, one liquid solution, and one intermediate compound. A thermodynamic description of this system is developed, which allows calculation of the phase diagram and thermodynamic properties. Two different solution models are used—a neutral species model with YO1.5 and ZrO2 as the components and a charged species model with Y3+, Zr4+, O2−, and vacancies as components. For each model, regular and subregular solution parameters are derived from selected phase equilibrium and thermodynamic data. The neutral species and charged species modeling results are compared.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Pulse-induced nanometer-scale lithography has been performed on graphite surfaces that were in contact with pure water or other organic liquids. Very reproducible control over the pit diameter was observed in aqueous solutions, and a well-defined voltage threshold (4.0±0.2 V) was also apparent. Near the threshold voltage, 7 A(ring) diameter×2 A(ring) high protrusions were formed, while larger initial pulse voltages resulted in pits of diameter(approximately-greater-than)20 A(ring).〈lz〉

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Correlations between the surface chemistry of etched, (100) oriented n-GaAs electrodes and their subsequent photoelectrochemical behavior have been probed by high-resolution x-ray photoelectron spectroscopy. GaAs photoanodes were chemically treated to prepare either an oxide-free near stoichiometric surface, a surface enriched in zero-valent arsenic (As0), or a substrate-oxide terminated surface. The current-voltage (I-V) behavior of each surface type was subsequently monitored in contact with several electrolytes.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

A photoelectrochemical anodization technique has been used to fabricate n-Si/insulator/metal (MIS) diodes with improved electrical properties. MIS structures fabricated with Au have provided the first experimental observation of a solid-state n-Si surface barrier device whose open circuit voltage Voc is controlled by minority-carrier bulk diffusion/recombination processes. For these diodes, variation of the minority-carrier diffusion length and majority-carrier dopant density produced changes in Voc that were in accord with bulk diffusion/recombination theory. Additionally, the variation in Voc in response to changes in the work function of the metal overlayer indicated that these MIS devices were not subject to the Fermi level pinning restrictions observed for n-Si Schottky structures. X-ray photoelectron spectroscopic characterization of the anodically grown insulator indicated 8.2±0.9 A(ring) of a strained SiO2 layer as the interfacial insulator resulting from the photoanodization process.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The transport of sputtered Ag atoms in the facing targets sputtering geometry studied by Monte Carlo simulation is presented. The atoms are ejected with a cosine distribution and undergo many collisions with the background argon gas atoms. The collisions are simulated with a Born–Mayer interaction potential. The model predicts the flux of Ag atoms arriving at the substrate, their energy, and angular distribution. These results have been compared with experimental results reported earlier. Similar computations have been extended to study the complex transport of multicomponent Y, Ba, and Cu in oxygen gas during YBa2Cu3O7−x sputter deposition. © 1998 American Institute of Physics.

Electronic Resource

1077-3118

AIP Digital Archive

Physics

Procedures are described for insulating metal scanning tunneling microscope (STM) tips with either glass or polymer coatings. In solutions containing 0.10 M of a reversible redox couple, Fe(CN)−3/−46 , the faradaic limiting current to polymer coated tips was 200–500 pA and that for glass coated tips was 〈10 pA. For polymer insulated tips, steady-state currents of 10–100 pA were observed at tip-sample displacements less than 0.3 μm. The suppression of faradaic current achieved by these coating procedures enabled the collection of the first atomic resolution STM images of highly ordered pyrolytic graphite electrodes in contact with redox-active electrolytes. Preliminary data for the in situ electrochemical characterization of these tips are also discussed.

Electronic Resource