Effect of germanium auto-diffusion on the bond lengths of Ga and P atoms in GaP/Ge(111) investigated by using X-ray absorption spectroscopy.

The germanium auto-diffusion effects on the inter-atomic distance between the nearest neighbors of the Ga atom in GaP epilayers are investigated using high-resolution X-ray diffraction (HRXRD) and X-ray absorption spectroscopy. The GaP layers grown on Ge (111) are structurally coherent and relaxed but they show the presence of residual strain which is attributed to the auto-diffusion of Ge from the results of secondary ion mass spectrometry and electrochemical capacitance voltage measurements. Subsequently, the inter-atomic distances between the nearest neighbors of Ga atom in GaP are determined from X-ray absorption fine-structure spectra performed at the Ga K-edge. The estimated local bond lengths of Ga with its first and second nearest neighbors show asymmetric variation for the in-plane and out-of-plane direction of GaP/Ge(111). The magnitude and direction of in-plane and out-of-plane microscopic residual strain present in the GaP/Ge are calculated from the difference in bond lengths which explains the presence of macroscopic residual tensile strain estimated from HRXRD. Modified nearest neighbor configurations of Ga in the auto-diffused GaP epilayer are proposed for new possibilities within the GaP/Ge hetero-structure, such as the conversion from indirect to direct band structures and engineering the tensile strain quantum dot structures on (111) surfaces.

Protonation-induced pH increase at the triblock copolymer micelle interface for transient membrane permeability at neutral pH.

Achieving controlled membrane permeability using pH-responsive block copolymers is crucial for selective intercellular uptake. We have shown that the pH at the triblock-copolymer micelle interface as compared to its bulk pH can help regulate membrane permeability. The pH-dependent acid/base equilibriums of two different interface-interacting pH probes were determined in order to measure the interfacial pH for a pH-responsive triblock copolymer (TBP) micelle under a wide range of bulk pH (4.5-9.0). According to 1H NMR studies, both pH probes provided interfacial pH at a similar interfacial depth. We revealed that the protonation of the amine moiety at the micelle interface and the subsequent formation of a positive charge caused the interface to become relatively less acidic than that of the bulk as well as an increase in the bulk-to-interfacial pH deviation (ΔpH) from ∼0.9 to 1.9 with bulk pH reducing from 8.0 to 4.5. From the ΔpH vs. interface and bulk pH plots, the apparent and intrinsic protonations or positive charge formation pKa values for the micelle were estimated to be ∼7.3 and 6.0, respectively. When the TBP micelle interacted with an anionic large unilamellar vesicle (LUV) of a binary lipid (neutral and anionic) system at the bulk pH of 7.0, fluorescence leakage studies revealed that the pH increase at the micelle interface from that of the LUV interface (pH ∼ 5.5) made the micelle interface partially protonated/cationic, thereby exhibiting transient membrane permeability. Although the increasing interface protonation causes the interface to become relatively less acidic than the bulk at any bulk pH below 6.5, the pH increase at the micelle interface may not be sufficiently large to maintain the threshold for the amine-protonated condition for effecting transient leakage and therefore, a continuous leakage was observed due to the slow disruption of the lipid bilayer.

Study of the microstructure information of GaAs epilayers grown on silicon substrate using synchrotron radiation.

Williamson-Hall (WH) analysis is a well established method for studying the microstructural properties of epilayers grown on foreign substrates. However, the method becomes inapplicable in specific cases where the structure factor considerations and the presence of anti-phase domains forbid the data acquisition for certain reflections in conventional high-resolution X-ray diffraction (HRXRD) measurements. Here, this limitation is overcome by exploiting the large intensity (25 µW mm(-2)) and high photon energy (15.5 keV) of the X-ray beam obtained from a synchrotron radiation source. The lateral coherence length, vertical coherence length, tilt and micro-strain of GaAs epilayers grown on Si substrate have been successfully measured using the conventional WH analysis. The microstructure information obtained from the conventional WH analysis based on the data acquired at the synchrotron radiation source is in reasonable agreement with the results obtained from atomic force microscope and surface profiler measurements. Such information cannot be obtained on a laboratory-based HRXRD system where modification of the WH method by involving a set of parallel asymmetric crystallographic planes is found to be essential. However, the information obtained from the modified WH method is along a different crystallographic orientation.

Reduced Sirtuin1 expression at the femoral neck in women who sustained an osteoporotic hip fracture.

UNLABELLED: To investigate the role of Sirtuin1 in osteoporosis, Sirtuin1 was determined at the femoral neck in female patients undergoing hip operation for fractured hip or osteoarthritis. Reduced Sirtuin1 was found in osteoporotic patients. Pharmacologic activation of Sirtuin1 reduced sclerostin, an inhibitor of bone formation. Activation of Sirtuin1 may be a new direction to generate therapies for osteoporosis. INTRODUCTION: The aim of the study are to investigate the role of Sirtuin1 (Sirt1), an anti-aging factor and a player in age-associated diseases, in osteoporotic hip fractures, and test the hypothesis that Sirt1 is a negative regulator of sclerostin, a bone formation inhibitor, in human femoral bone marrow mesenchymal cells (BM-MSCs). METHODS: Sirt1 and sclerostin were determined by western blot in bone samples obtained intra-operatively from the inferior medial cortex of the femoral neck (calcar region) in female patients undergoing partial hip replacement for fractured neck of femur (N = 10) or hip replacement for osteoarthritis (N = 8) (mean ± SD age 81 ± 8.1 vs. 68 ± 9.3 years; BMI 26.2 ± 3.6 vs. 25.9 ± 7.1 kg/m(2) in osteoporotic and osteoarthritis patients). Calcar thickness and femoral bone mineral density (BMD) were determined preoperatively by X-ray using a digital TraumaCad(™) software and DEXA. Femoral BM-MSCs were collected intra-operatively and treated with SRT3025, a Sirt1 activator. Sclerostin and dentin matrix acidic phosphoprotein (DMP1) were determined by western blot and messenger RNA (mRNA) expression of Lef1 and DMP1 was evaluated by quantitative real-time PCR. RESULTS: Osteoporotic (OP) patients had reduced cortical thickness, femoral neck, and total hip BMD compared to osteoarthritis (OA) patients. Calcar Sirt1 expression was significantly reduced, while sclerostin was markedly increased in OP compared to OA patients. Sirt1 and sclersotin expressions were inversely correlated (r = -0.49, P = 0.047). SRT3025 administration down-regulated sclerostin and up-regulated DMP1 protein level and increased LEF1 and DMP1 mRNA expressions in OP patient-derived BM-MSCs. CONCLUSIONS: Reduced femoral neck Sirt1 may play a role in osteoporotic hip fractures in part via influencing local sclerostin expression. The therapeutic potential of Sirt1 activation in osteoporosis warrants further investigation.

Solitary rectal ulcer syndrome: clinical, endoscopic, histological and anorectal manometry findings in north Indian patients.

BACKGROUND: Solitary rectal ulcer syndrome (SRUS) is a chronic, benign defecation disorder often related to excessive straining. SRUS is diagnosed on the basis of clinical symptoms, endoscopic and histological findings. METHODS: All patients diagnosed with SRUS by colonoscopy and confirmed by histopathology from October 2012 to August 2014 in the Department of Gastroenterology, Institute of Medical Sciences, Banaras Hindu University, India, were included in the study. Out of 92 patients, thirty-four patients underwent anorectal manometry. Twenty age-matched healthy volunteers were also studied with anorectal manometry to serve as controls. RESULTS: Mean age of the group was 41 ± 19 years with age range of 10-82 years; males were 58 (63%) with male to female ratio of 1.7:1. Bleeding per rectum was present in 83%, constipation in 46.7%, abdominal pain in 27.2%, and diarrhea in 25% of the patients. On endoscopy, ulcerative lesions were seen in 83% patients of whom solitary and multiple lesions were present in 44% and 39%, respectively. Polypoidal lesions were reported in 17.4% whilst rectal polyps and erythematous mucosa were found in 5.4% and 2.2%, respectively. Histological examination revealed fibromuscular obliteration in 100% of patients, surface ulceration in 70.6% and crypt distortion in 20.65% of patients. Anal relaxation and balloon expulsion test was significantly abnormal in SRUS patients compared to healthy controls (53% vs. 20%, p < 0.01). CONCLUSION: Rectal bleeding was the most common symptom and ulcerative lesions the most common endoscopic finding. Fecal evaluation disorder was more prevalent inpatients with SRUS.

Meta-analysis of observational studies: hepatitis C and survival after renal transplant.

Recent evidence has shown that anti-HCV-positive serologic status is significantly linked to lower patient and graft survival after renal transplant, but conflicting results have been given on this point. The aim of this study was to conduct a systematic review of the published medical literature concerning the impact of HCV infection on all-cause mortality and graft loss after RT. The relative risk of all-cause mortality and graft loss was regarded as the most reliable outcome end-point. Study-specific relative risks were weighted by the inverse of their variance to obtain fixed- and random-effect pooled estimates for mortality and graft loss with HCV across the published studies. We identified eighteen observational studies involving 133 530 unique renal transplant recipients. The summary estimate for adjusted relative risk (aRR) of all-cause mortality was 1.85 with a 95% confidence interval (CI) of 1.49; 2.31 (P < 0.0001); heterogeneity statistics, Ri = 0.87 (P-value by Q-test = 0.001). The overall estimate for adjusted RR of all-cause graft loss was 1.76 (95% CI, 1.46; 2.11) (P < 0.0001), heterogeneity statistics, Ri = 0.65 (P-value by Q-test = 0.001). Stratified analysis did not change meaningfully these results. Meta-regression showed that living donor rate had a favourable influence on patient (P = 0.031) and graft survival (P = 0.01), whilst diabetes mellitus having a detrimental role on patient survival (P = 0.001). This meta-analysis of observational studies supports the notion that HCV-positive patients after RT have an increased risk of mortality and graft loss. Further studies are in progress to understand better the mechanisms underlying the relationship between HCV and mortality or graft dysfunction after renal transplant.

Antiviral therapy (pegylated interferon and ribavirin) of hepatitis C in dialysis patients: meta-analysis of clinical studies.

Information on the antiviral treatment (pegylated interferon plus ribavirin) of chronic infection by hepatitis C virus (HCV) in patients on long-term dialysis is extremely limited. We evaluated the efficacy and safety of combination antiviral therapy (pegylated interferon plus ribavirin) in patients on long-term dialysis with chronic hepatitis C by performing a systematic review of the literature with a meta-analysis of clinical studies. The primary outcome was sustained virological response (SVR) (as a measure of efficacy); the secondary outcome was dropout rate (as a measure of tolerability). We used the random-effects model of DerSimonian and Laird, with heterogeneity and sensitivity analyses. We identified eleven clinical studies (287 unique patients), two of them being controlled clinical trials. The summary estimate for SVR and dropout rate was 0.60 (95% Confidence Intervals, 0.47; 0.71) and 0.18 (95% CI, 0.08; 0.35), respectively; studies being heterogeneous with regard to both the outcomes. Stratified analysis reported a higher SVR rate in controlled trials, 0.86 (95% CI, 0.27; 0.99). The most common sources of dropout were anaemia (11/46 = 23%) and infections (6/46 = 13%). Meta-regression analysis showed a detrimental impact of HCV genotype 1 (P = 0.036) and dropout (P = 0.0001) rate upon the frequency of SVR. Antiviral therapy based on pegylated interferon plus ribavirin for HCV gives encouraging results in terms of efficacy and safety among patients on long-term dialysis; such approach should be considered the current standard of care for HCV-infected individuals on regular dialysis.

Evaluation of 5α-reductase inhibitory activity of certain herbs useful as antiandrogens.

This study demonstrates 5α-reductase inhibitory activity of certain herbs useful in the management of androgenic disorders. Ganoderma lucidum (Curtis) P. Karst (GL), Urtica dioica Linn. (UD), Caesalpinia bonducella Fleming. (CB), Tribulus terrestris Linn. (TT), Pedalium murex Linn. (PM), Sphaeranthus indicus Linn. (SI), Cuscuta reflexa Roxb. (CR), Citrullus colocynthis Schrad. (CC), Benincasa hispida Cogn. (BH), Phyllanthus niruri Linn. (PN) and Echinops echinatus Linn. (EE) were included in the study. Petroleum ether, ethanol and aqueous extracts of these herbs were tested for their 5α-reductase inhibitory activity against the standard 5α-reductase inhibitor, finasteride. A biochemical method to determine the activity of 5α-reductase was used to evaluate the inhibition of different extracts to the enzyme. The optical density (OD) value of each sample was measured continuously with ultraviolet spectrophotometer for the reason that the substrate NADPH has a specific absorbance at 340 nm. As the enzyme 5α-reductase uses NADPH as a substrate, so in the presence of 5α-reductase inhibitor, the NADPH concentration will increase with the function of time. This method thus implicates the activity of 5α-reductase. The method proved to be extremely useful to screen the herbs for their 5α-reductase inhibitory potential. GL, UD, BH, SI and CR came out to be promising candidates for further exploring their antiandrogenic properties.

Correlation of age and hepatitis B virus DNA levels with histological activity in HBeAg negative chronic hepatitis B patients.

BACKGROUND: The relationship between age and serum HBV DNA levels with histological activity in chronic hepatitis B inactive carriers is still unclear. We evaluated the correlation between age and hepatitis B viral DNA levels with Metavir score in inactive chronic HBV carriers. METHODS: 50 patients (30 males and 20 females) were enrolled in the study after informed consent. Their blood samples were taken for routine investigations and specific tests for the study. Serum HBV DNA levels were quantified by real-time PCR. Metavir score was used for histologic grading. RESULTS: A1F0, A1F1, A1F2, A2F2 and A2F3 metavir scores were found in 41 (82%), 4 (8%), 1 (2%), 3 (6%), and 1 (2%) patients, respectively. There was significant correlation between age > 40 years and Metavir scores (p < 0.001). However there was no significant correlation between HBV DNA level with Metavir score (p = 0.074). CONCLUSION: Inactive carriers of 40 years of age or more should undergo liver biopsy to look for presence of significant histological findings despite having low HBV DNA level and normal SGPT level.

Emerging artificial intelligence-aided diagnosis and management methods for ischemic strokes and vascular occlusions: A comprehensive review.

Large-vessel occlusion (LVO) stroke is a promising field for the use of AI, especially machine learning (ML) because optimal results are highly dependent on timely diagnosis, communication, and treatment. In order to better understand the current state of artificial intelligence (AI) in relation to LVO strokes, its efficacy, and potential future applications, we searched relevant literature to perform a comprehensive evaluation of the topic. The databases PubMed, Embase, and Scopus were extensively searched for this review. Studies were then screened using title and abstract criteria and duplicate studies were excluded. By using pre-established inclusion and exclusion criteria, it was decided whether or not to include full-text papers in the final analysis. The studies were analyzed, and the relevant information was retrieved. In recognizing LVO on computed tomography, ML approaches were very accurate. There is a shortage of AI applications for thrombectomy patient selection, despite the fact that certain research accurately evaluates individual patient eligibility for endovascular therapy. Machine learning algorithms may reasonably predict clinical and angiographic outcomes as well as associated factors. AI has shown promise in the diagnosis and treatment of people who have just suffered a stroke. However, the usefulness of AI in management and forecasting remains restricted, necessitating more studies into machine learning applications that can guide decision making in the future.