Electron Heat Source Driven Heat Transport in GaN at Nanoscale: Electron-Phonon Monte Carlo Simulations and a Two Temperature Model.

The thermal energy transport in semiconductors is mostly determined by phonon transport. However in polar semiconductors like GaN electronic contribution to the thermal transport is non-negligible. In this paper, we use an electron-phonon Monte Carlo (MC) method to study temperature distribution and thermal properties in a two-dimensional GaN computational domain with a localized, steady and continuous electron heat source at one end. Overall, the domain mimics the two-dimensional electron gas (2DEG) channel of a typical GaN high electron mobility transistor (HEMT). High energy electrons entering the domain from the source interact with the phonons, and drift under the influence of an external electric field. Cases of the electric field being uniform and non-uniform are investigated separately. A two step/temperature analytical model is proposed to describe the electron as well as phonon temperature profiles and solved using the finite difference method (FDM). The FDM results are compared with the MC results and found to be in good agreement.

An evaluation of liposome-based diagnostics of pulmonary and extrapulmonary tuberculosis.

Introduction: Tuberculosis (TB) is still one of the major global health threats and delayed diagnosis or misdiagnosis continues to fuel the global epidemic. The conventional diagnostic approaches have shortcomings that might hinder the process of diagnosis of the disease and ultimately affect the prognosis.Area covered: We emphasize on the process of the synthesis of liposomes, its physicochemical properties affecting the formulation and their utilization in the field of molecular diagnostics for TB. The review also sheds a light on other nanoparticle-based molecular diagnostic approaches for TB. Despite the advent of science, we are yet to have a diagnostic tool that is simple, rapid, sensitive, and specific, and most importantly, one that enables us to demarcate patients with active tuberculosis from those with quiescent lesions, prior vaccination, or other diseases.Expert opinion: The utility of liposomes for diagnostic purposes has been attempted so as to overcome the challenges posed by conventional diagnostic tools for TB. Through this review, we present insights into liposome formulation and selection processes, various studies that report the use of liposome-based diagnostic tools for TB, as well as the limitations associated with the same that can be improvised to make the technology more efficient.

Status of antioxidant and lipid peroxidation in type 2 diabetic human subjects diagnosed with and without metabolic syndrome by using NCEP-ATPIII, IDF and WHO criteria.

BACKGROUND: Antioxidants play a very crucial role in terms of disease incidence and its complications. Type 2 diabetes and metabolic syndrome (MetS) are now more prevalent than any other disorder. In this regard this study focuses on type 2 diabetic subjects with MetS having highest incidence of cardiovascular disease. Hence the aim of the study was to reveal the level of antioxidants and lipid peroxidation in MetS and non-MetS groups of type 2 diabetic subjects characterized by three different criteria. METHODS: Present study was based on 70 type 2 diabetic subjects and 20 healthy controls. The metabolic syndrome criteria were defined by National Cholesterol Education Program (NCEP)-Adult Treatment Panel III (ATPIII), International Diabetes Federation (IDF), and World Health Organization (WHO). The selected subjects were of similar age group. The participants were selected from a diabetic camp being run in the University Campus. The antioxidant enzymes estimated were reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) while Thiobarbituric acid reactive substances (TBARS) measured as a marker of lipid peroxidation. RESULTS: The level of GSH, CAT, SOD decreases in non-MetS and MetS subjects as compared to normal. When comparison was made for GSH & SOD in the mentioned groups resulted a significant differences in non-MetS and MetS compared with normal subjects. TBARS levels was increased in non-MetS and MetS group of subjects. The results indicate reduction in antioxidant enzymes and elevation of lipid peroxidation in type 2 diabetic subjects with or without MetS defined by using any of the International criteria. CONCLUSIONS: The study revealed that absolute reduction of antioxidant and involvement of lipid peroxidation in MetS group may lead to progressive intensification of cardiovascular disease in type 2 diabetic subjects irrespective of using any criteria.

Microchannel-based regenerative scaffold for chronic peripheral nerve interfacing in amputees.

Neurally controlled prosthetics that cosmetically and functionally mimic amputated limbs remain a clinical need because state of the art neural prosthetics only provide a fraction of a natural limb's functionality. Here, we report on the fabrication and capability of polydimethylsiloxane (PDMS) and epoxy-based SU-8 photoresist microchannel scaffolds to serve as viable constructs for peripheral nerve interfacing through in vitro and in vivo studies in a sciatic nerve amputee model where the nerve lacks distal reinnervation targets. These studies showed microchannels with 100 µm × 100 µm cross-sectional areas support and direct the regeneration/migration of axons, Schwann cells, and fibroblasts through the microchannels with space available for future maturation of the axons. Investigation of the nerve in the distal segment, past the scaffold, showed a high degree of organization, adoption of the microchannel architecture forming 'microchannel fascicles', reformation of endoneurial tubes and axon myelination, and a lack of aberrant and unorganized growth that might be characteristic of neuroma formation. Separate chronic terminal in vivo electrophysiology studies utilizing the microchannel scaffolds with permanently integrated microwire electrodes were conducted to evaluate interfacing capabilities. In all devices a variety of spontaneous, sensory evoked and electrically evoked single and multi-unit action potentials were recorded after five months of implantation. Together, these findings suggest that microchannel scaffolds are well suited for chronic implantation and peripheral nerve interfacing to promote organized nerve regeneration that lends itself well to stable interfaces. Thus this study establishes the basis for the advanced fabrication of large-electrode count, wireless microchannel devices that are an important step towards highly functional, bi-directional peripheral nerve interfaces.

Lipid-lowering and antioxidant functions of bottle gourd (Lagenaria siceraria) extract in human dyslipidemia.

The study validated the antidyslipidemic, antioxidant, and antihyperglycemic effects of Lagenaria siceraria fruit extract in human subjects with dyslipidemia along with subjects of normal health. A total of 200 mL of freshly prepared Lagenaria siceraria fruit extract was administered daily on empty stomach for 90 days. Significant reductions (P < .01) were found in triglycerides and total cholesterol levels in blood. Cardiac risk ratio, atherogenic coefficient, and atherogenicity index of plasma were also improved. Appreciable reductions in body mass index (P < .01) and blood pressure (systolic P < .01, diastolic P < .05) along with a significant reduction (P < .05) in fasting blood glucose levels were also observed in these subjects. Lagenaria siceraria fruit extract exhibited significant antioxidant activity in dyslipidemic subjects as evident from elevations in SOD (P < .05) and GSH levels (P < .01) with marked improvement in catalase (P < .01) and TBARS levels (P < .05). Phytochemical screening confirmed the presence of saponins, glycosides, flavonoids, terpenoids, and phenolic compounds. Lagenaria siceraria fruit extract serves as dietary adjunct in treatment of human dyslipidemia and cardiovascular disease.

ß-Catenin gain of function in muscles impairs neuromuscular junction formation.

Neuromuscular junction (NMJ) formation requires proper interaction between motoneurons and muscle cells. ß-Catenin is required in muscle cells for NMJ formation. To understand underlying mechanisms, we investigated the effect of ß-catenin gain of function (GOF) on NMJ development. In HSA-ß-cat(flox(ex3)/+) mice, which express stable ß-catenin specifically in muscles, motor nerve terminals became extensively defasciculated and arborized. Ectopic muscles were observed in the diaphragm and were innervated by ectopic phrenic nerve branches. Moreover, extensive outgrowth and branching of spinal axons were evident in the GOF mice. These results indicate that increased ß-catenin in muscles alters presynaptic differentiation. Postsynaptically, AChR clusters in HSA-ß-cat(flox(ex3)/+) diaphragms were distributed in a wider region, suggesting that muscle ß-catenin GOF disrupted the signal that restricts AChR clustering to the middle region of muscle fibers. Expression of stable ß-catenin in motoneurons, however, had no effect on NMJ formation. These observations provide additional genetic evidence that pre- and postsynaptic development of the NMJ requires an intricate balance of ß-catenin activity in muscles.