Evidence for Charging Effects in CdTe/CdMgTe Quantum Point Contacts

Here we report on fabrication and low temperature magnetotransport measurements of quantum point contacts patterned from a novel two-dimensional electron system - CdTe/CdMgTe modulation doped heterostructure. From the temperature and bias dependence we ascribe the reported data to evidence for a weakly bound state which is naturally formed inside a CdTe quantum constrictions due to charging effects. We argue that the spontaneous introduction of an open dot is responsible for the replacement of flat conductance plateaus by quasi-periodic resonances with amplitude less than 2e^{2}/h, as found in our system. Additionally, below 1 K a pattern of weaker conductance peaks, superimposed upon wider resonances, is also observed.Comment: 4 pages, 4 figure

Deformed Heisenberg algebra and minimal length

A one-dimensional deformed Heisenberg algebra $[X,P]=if(P)$ is studied. We answer the question: For what function of deformation $f(P)$ there exists a nonzero minimal uncertainty in position (minimal length). We also find an explicit expression for the minimal length in the case of arbitrary function of deformation.Comment: to be published in JP

Motivation for youth educational services level State-Universiti-teacher

В статті розглядається мотивація викладачів до ефективної праці та студентів до якісної освіти на рівні Держава – ВНЗ – викладач. Наведено результати соціологічного дослідження проведеного серед студентів та викладачів одеського національного економічного університету. Зроблені висновки та надано пропозиції щодо вдосконалення мотиваційного механізму до отримання якісної освіти для студентів та ефективної праці викладача в сучасних умовах ринкових змін.В статье рассматривается мотивация преподавателей к эффективному труду и студентов к качественному образованию на уровне Государство - ВУЗ - преподаватель. Приведены результаты социологического исследования, проведенного среди студентов и преподавателей одесского национального экономического университета. Сделанные выводы и даны предложения по совершенствованию мотивационного механизма к получению качественного образования для студентов и эффективной работы преподавателя в современных условиях рыночных преобразований.In the article the motivation of teachers to work effectively and students to quality education at State - University - teacher. The results of a sociological survey conducted among students and teachers of the Odessa National Economic University. The conclusions and submitted proposals to improve the motivational mechanism for quality education for students and teacher work effectively in today's market conditions change

Complex bounds for multimodal maps: bounded combinatorics

We proved the so called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus. The complex bounds is the first step to extend the renormalization theory of unimodal maps to multimodal maps.Comment: 20 pages, 3 figure

Non-universal equilibrium crystal shape results from sticky steps

The anisotropic surface free energy, Andreev surface free energy, and equilibrium crystal shape (ECS) z=z(x,y) are calculated numerically using a transfer matrix approach with the density matrix renormalization group (DMRG) method. The adopted surface model is a restricted solid-on-solid (RSOS) model with "sticky" steps, i.e., steps with a point-contact type attraction between them (p-RSOS model). By analyzing the results, we obtain a first-order shape transition on the ECS profile around the (111) facet; and on the curved surface near the (001) facet edge, we obtain shape exponents having values different from those of the universal Gruber-Mullins-Pokrovsky-Talapov (GMPT) class. In order to elucidate the origin of the non-universal shape exponents, we calculate the slope dependence of the mean step height of "step droplets" (bound states of steps) using the Monte Carlo method, where p=(dz/dx, dz/dy)$, and represents the thermal averag |p| dependence of , we derive a |p|-expanded expression for the non-universal surface free energy f_{eff}(p), which contains quadratic terms with respect to |p|. The first-order shape transition and the non-universal shape exponents obtained by the DMRG calculations are reproduced thermodynamically from the non-universal surface free energy f_{eff}(p).Comment: 31 pages, 21 figure

Recovery from hind limb ischemia is less effective in type 2 than in type 1 diabetic mice: Roles of endothelial nitric oxide synthase and endothelial progenitor cells

ObjectiveWe sought to directly compare the effects of type 1 and type 2 diabetes on postischemic neovascularization and evaluate the mechanisms underlying differences between these groups. We tested the hypothesis that type 2 diabetic mice have a greater reduction in endothelial nitric oxide synthase (eNOS) expression, a greater increase in oxidative stress, and reduced arteriogenesis and angiogenesis, resulting in less complete blood flow recovery than type 1 diabetic mice after induction of hind limb ischemia.MethodsHind limb ischemia was generated by femoral artery excision in streptozotocin-treated mice (model of type 1 diabetes), in Leprdb/db mice (model of type 2 diabetes), and in control (C57BL/6) mice. Dependent variables included eNOS expression and markers of arteriogenesis, angiogenesis, and oxidative stress.ResultsPostischemia recovery of hind limb perfusion was significantly less in type 2 than in type 1 diabetic mice; however, neither group demonstrated a significant increase in collateral artery diameter or collateral artery angioscore in the ischemic hind limb. The capillary/myofiber ratio in the gastrocnemius muscle decreased in response to ischemia in control or type 1 diabetic mice but remained the same in type 2 diabetic mice. Gastrocnemius muscle eNOS expression was lower in type 1 and 2 diabetic mice than in control mice. This expression decreased after induction of ischemia in type 2 but not in type 1 diabetic mice. The percentage of endothelial progenitor cells (EPC) in the peripheral blood failed to increase in either diabetic group after induction of ischemia, whereas this variable significantly increased in the control group in response to ischemia. EPC eNOS expression decreased after induction of ischemia in type 1 but not in type 2 diabetic mice. EPC nitrotyrosine accumulation increased after induction of ischemia in type 2 but not in type 1 diabetic mice. EPC migration in response to vascular endothelial growth factor was reduced in type 1 and type 2 diabetic mice vs control mice. EPC incorporation into tubular structures was less effective in type 2 diabetic mice. Extensive fatty infiltration was present in ischemic muscle of type 2 but not in type 1 diabetic mice.ConclusionType 2 diabetic mice displayed a significantly less effective response to hind limb ischemia than type 1 diabetic mice.Clinical RelevanceDiabetes is important in the pathogenesis of peripheral artery disease. The present study demonstrates that the vascular response to acute hind limb ischemia is dependent on the type of diabetes present. Type 2 diabetic mice (Leprdb/db) demonstrated significantly less effective blood flow recovery than type 1 diabetic mice (streptozotocin-induced). Moreover, the differences between diabetic groups appeared contingent, at least in part, on differences in endothelial nitric oxide, oxidant stress, and endothelial progenitor cell function between the two diabetic groups. Although direct extrapolation of animal data to the human experience must be made with caution, these findings indicate that the type of diabetes present, and not just the presence of diabetes per se, may be important in the initiation of progression of peripheral artery disease

Identification of Specific Inhibitors of Trypanosoma cruzi Malic Enzyme Isoforms by Target-Based HTS.

Trypanosoma cruzi is the causative agent of Chagas disease. The lack of an efficient and safe treatment supports the research into novel metabolic targets, with the malic enzyme (ME) representing one such potential candidate. T. cruzi expresses a cytosolic (TcMEc) and a mitochondrial (TcMEm) ME isoform, with these activities functioning to generate NADPH, a key source of reducing equivalents that drives a range of anabolic and protective processes. To identify specific inhibitors that target TcMEs, two independent high-throughput screening strategies using a diversity library containing 30,000 compounds were employed. IC50 values of 262 molecules were determined for both TcMEs, as well as for three human ME isoforms, with the inhibitors clustered into six groups according to their chemical similarity. The most potent hits belonged to a sulfonamide group that specifically target TcMEc. Moreover, several selected inhibitors of both TcMEs showed a trypanocidal effect against the replicative forms of T. cruzi. The chemical diversity observed among those compounds that inhibit TcMEs activity emphasizes the druggability of these enzymes, with a sulfonamide-based subset of compounds readily able to block TcMEc function at a low nanomolar range.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported by Sao Paulo Research Foundation (FAPESP) (process numbers 2013/03983-5, 2012/23682-7, and 2015/03336-5)

The amino-acid stress sensing eIF2α kinase GCN2 is a survival biomarker for malignant mesothelioma

BackgroundMalignant mesothelioma is a tumour that is strongly associated with a history of asbestos exposure, and which derives from mesothelial cells that line the serous cavities of the body. The tumour most commonly arises in the pleural cavity, but can also arise in the pericardium, peritoneum, and tunica vaginalis. At present the lesion has a very poor prognosis and is an incurable form of cancer with median survival times of up to 19 months being quoted for some histological subtypes. A large proportion of mesotheliomas have been shown to be arginine auxotrophic, leading to new research for therapeutics which might exploit this potential vulnerability.MethodsWe measured the levels of General Control Non-derepressible 2 (GCN2) protein in malignant mesothelioma tumour samples and determined whether these levels correlate with clinical outcomes.ResultsWe observed that the expression levels of GCN2 correlated with patient survival and was an independent prognostic variable in pairwise comparisons with all available clinical data.ConclusionThese findings suggest that GCN2 levels provides prognostic information and may allow for stratification of care pathways. It may suggest that targeting GCN2 is a viable strategy for mesothelioma therapy development

The Probing In-Situ With Neutron and Gamma Rays (PING) Instrument for Planetary Composition Measurements

The Probing In situ with Neutrons and Gamma rays (PING) instrument (formerly named PNG-GRAND) [I] experiment is an innovative application of the active neutron-gamma ray technology successfully used in oil field well logging and mineral exploration on Earth over many decades. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring PING to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets and measure their bulk surface and subsurface elemental composition without the need to drill into the surface. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions. While orbital measurements can map a planet, they have low spatial and elemental sensitivity due to the low surface gamma ray emission rates reSUlting from using cosmic rays as an excitation source, PING overcomes this limitation in situ by incorporating a powerful neutron excitation source that permits significantly higher elemental sensitivity elemental composition measurements. PING combines a 14 MeV deuterium-tritium Pulsed Neutron Generator (PNG) with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface, The penetrating nature of .5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design, We are cun'ently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x ,9 m) granite and basalt test formations placed outdoors in an empty field, Since an independent trace elemental analysis has been performed on both these Columbia River basalt and Concord Gray granite materials, these large samples present two known standards with which to compare PING's experimentally measured elemental composition results, We will present both gamma ray and neutron experimental results from PING measurements of the granite and basalt test formations in various layering configurations and compare the results to the known composition