High gas pressure and high-temperature synthesis (HP-HTS) technique and its impact on iron-based superconductors

The high-pressure growth technique generally plays an important role in the improvement of the sample quality and the enhancement of various physical and magnetic properties of materials. The high gas pressure technique provides a large sample space (10-15 cm) to grow various kinds of materials. In this paper, we introduce the high gas pressure and high-temperature synthesis (HP-HTS) technique that is present at our institute and is applied to the growth process of different kinds of superconducting materials, particularly iron-based superconductors. More details and the working principle of this HP-HTS technique are discussed. We have also demonstrated the current results based on the iron-based superconductors by using this unique HP-HTS technique. These results demonstrate the enhancement of the superconducting properties with the improved sample quality compared to the conventional synthesis process at ambient pressure.Comment: 12 pages, 8 figure

ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF TABERNAEMONTANA HEYNEANA WALL. AN ENDEMIC PLANT OF WESTERN GHATS

Objective: The aim of this study was to investigate the antioxidant and antimicrobial properties of different crude extracts of leaves of T. heyneanaMethods: Crude extracts of methanol, chloroform, dichloromethane and dichloroethane of leaf were evaluated for antimicrobial activity by disc diffusion method and antioxidant activity by DPPH (diphenyl-2-picrylhydrazyl) and reducing power assay. Quantitative analysis of total phenolics was done by Folin-Ciocalteau method and total flavonoids by aluminium chloride method.Results: Methanolic extract of T. heyneana exhibited the presence of all the phytochemicals tested except triterpenoids and saponins. The highest phenolic content of 14.0±0.45 mg GAE/g and flavonoid content of 81.62±0.47 mg QE/g were found in methanol extract. The highest DPPH scavenging activity (IC50 20.3±0.56 µg/ml) and reducing power was exhibited by methanolic extract. The methanolic extract showed maximum antibacterial activity of 12.66±0.57 mm zone of inhibition against Staphylococcus aureus and least of 9.23±0.25 mm against Proteus vulgaris.Conclusion: These findings provide scientific evidence to support the traditional use of Tabernaemontana heyneana Wall. and also indicate that the leaves of this species are a promising potential for the development of antioxidant and antimicrobial agents

Design and Implementation of Modified Zeta Converter for Solar Water Pumping Application

The linear increase in the growth of the population demands a requisite for energy resources. Knowing the loathsome truth that non-renewable sources will ultimately exhaust, the significance of renewable sources cannot be undervalued. Considering various factors, many work areas are reliant upon fossil fuels for the generation of electricity. The use of fossil fuels will increase the quality of power production but will drain one day, and industries must change to renewable sources. The earliest system that strikes a chord with regard to renewable energy is the photovoltaic (PV) energy system. In this specific circumstance, interest in solar systems is expanding step by step, and its installations are becoming broad. The implementation of the solar water pumping method used for irrigation purposes using a Zeta converter was best suited for small and minor farmers, but still, the efficiency of the system can be upgraded with the use of filters. The vantage of the ZETA converter has less result voltage ripple and smooth water pumping application. The PV-based system has reached the point where it is used in Electric vehicles by enhancing the standard operating condition of the converter under the steady and dynamic behavior of a PV system. Eventually, it can be worked considerably under minimum solar irradiance. Maximum power point tracking (MPPT) of the signal had dominant performance in a zeta converter circuit while sign levels ripple current, and voltage on the output side was compact

Drug resistance in children at virological failure in a rural KwaZulu-Natal, South Africa, cohort.

BACKGROUND: Better understanding of drug resistance patterns in HIV-infected children on antiretroviral therapy (ART) is required to inform public health policies in high prevalence settings. The aim of this study was to characterise the acquired drug resistance in HIV-infected children failing first-line ART in a decentralised rural HIV programme. METHODS: Plasma samples were collected from 101 paediatric patients (≤15 yrs of age) identified as failing ART. RNA was extracted from the plasma, reverse transcribed and a 1.3 kb region of the pol gene was amplified and sequenced using Sanger sequencing protocols. Sequences were edited in Geneious and drug resistance mutations were identified using the RegaDB and the Stanford resistance algorithms. The prevalence and frequency of mutations were analysed together with selected clinical and demographic data in STATA v11. RESULTS: A total of 101 children were enrolled and 89 (88%) were successfully genotyped; 73 on a non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based regimen and 16 on a protease inhibitor (PI)-based regimen at the time of genotyping. The majority of patients on an NNRTI regimen (80%) had both nucleoside reverse-transcriptase inhibitor (NRTI) and NNRTI resistance mutations. M184V and K103N were the most common mutations amongst children on NNRTI-based and M184V among children on PI-based regimens. 30.1% had one or more thymidine analogue mutation (TAM) and 6% had ≥3 TAMs. Only one child on a PI-based regimen harboured a major PI resistance mutation. CONCLUSIONS: Whilst the patterns of resistance were largely predictable, the few complex resistance patterns seen with NNRTI-based regimens and the absence of major PI mutations in children failing PI-based regimens suggest the need for wider access to genotypic resistance testing in this setting

A YY1-dependent increase in aerobic metabolism is indispensable for intestinal organogenesis

During late gestation, villi extend into the intestinal lumen to dramatically increase the surface area of the intestinal epithelium, preparing the gut for the neonatal diet. Incomplete development of the intestine is the most common gastrointestinal complication in neonates, but the causes are unclear. We provide evidence in mice that Yin Yang 1 (Yy1) is crucial for intestinal villus development. YY1 loss in the developing endoderm had no apparent consequences until late gestation, after which the intestine differentiated poorly and exhibited severely stunted villi. Transcriptome analysis revealed that YY1 is required for mitochondrial gene expression, and ultrastructural analysis confirmed compromised mitochondrial integrity in the mutant intestine. We found increased oxidative phosphorylation gene expression at the onset of villus elongation, suggesting that aerobic respiration might function as a regulator of villus growth. Mitochondrial inhibitors blocked villus growth in a fashion similar to Yy1 loss, thus further linking oxidative phosphorylation with late-gestation intestinal development. Interestingly, we find that necrotizing enterocolitis patients also exhibit decreased expression of oxidative phosphorylation genes. Our study highlights the still unappreciated role of metabolic regulation during organogenesis, and suggests that it might contribute to neonatal gastrointestinal disorders

Southern African Treatment Resistance Network (SATuRN) RegaDB HIV drug resistance and clinical management database: supporting patient management, surveillance and research in southern Africa

Substantial amounts of data have been generated from patient management and academic exercises designed to better understand the human immunodeficiency virus (HIV) epidemic and design interventions to control it. A number of specialized databases have been designed to manage huge data sets from HIV cohort, vaccine, host genomic and drug resistance studies. Besides databases from cohort studies, most of the online databases contain limited curated data and are thus sequence repositories. HIV drug resistance has been shown to have a great potential to derail the progress made thus far through antiretroviral therapy. Thus, a lot of resources have been invested in generating drug resistance data for patient management and surveillance purposes. Unfortunately, most of the data currently available relate to subtype B even though >60% of the epidemic is caused by HIV-1 subtype C. A consortium of clinicians, scientists, public health experts and policy markers working in southern Africa came together and formed a network, the Southern African Treatment and Resistance Network (SATuRN), with the aim of increasing curated HIV-1 subtype C and tuberculosis drug resistance data. This article describes the HIV-1 data curation process using the SATuRN Rega database. The data curation is a manual and time-consuming process done by clinical, laboratory and data curation specialists. Access to the highly curated data sets is through applications that are reviewed by the SATuRN executive committee. Examples of research outputs from the analysis of the curated data include trends in the level of transmitted drug resistance in South Africa, analysis of the levels of acquired resistance among patients failing therapy and factors associated with the absence of genotypic evidence of drug resistance among patients failing therapy. All these studies have been important for informing first- and second-line therapy. This database is a free password-protected open source database available on www.bioafrica.net

Implementing antiretroviral resistance testing in a primary health care HIV treatment programme in rural KwaZulu-Natal, South Africa: early experiences, achievements and challenges.

BACKGROUND: Antiretroviral drug resistance is becoming increasingly common with the expansion of human immunodeficiency virus (HIV) treatment programmes in high prevalence settings. Genotypic resistance testing could have benefit in guiding individual-level treatment decisions but successful models for delivering resistance testing in low- and middle-income countries have not been reported. METHODS: An HIV Treatment Failure Clinic model was implemented within a large primary health care HIV treatment programme in northern KwaZulu-Natal, South Africa. Genotypic resistance testing was offered to adults (≥16 years) with virological failure on first-line antiretroviral therapy (one viral load >1000 copies/ml after at least 12 months on a standard first-line regimen). A genotypic resistance test report was generated with treatment recommendations from a specialist HIV clinician and sent to medical officers at the clinics who were responsible for patient management. A quantitative process evaluation was conducted to determine how the model was implemented and to provide feedback regarding barriers and challenges to delivery. RESULTS: A total of 508 specimens were submitted for genotyping between 8 April 2011 and 31 January 2013; in 438 cases (86.2%) a complete genotype report with recommendations from the specialist clinician was sent to the medical officer. The median turnaround time from specimen collection to receipt of final report was 18 days (interquartile range (IQR) 13-29). In 114 (26.0%) cases the recommended treatment differed from what would be given in the absence of drug resistance testing. In the majority of cases (n = 315, 71.9%), the subsequent treatment prescribed was in line with the recommendations of the report. CONCLUSIONS: Genotypic resistance testing was successfully implemented in this large primary health care HIV programme and the system functioned well enough for the results to influence clinical management decisions in real time. Further research will explore the impact and cost-effectiveness of different implementation models in different settings