DST Systems

About: DST Systems is a based out in . It is known for research contribution in the topics: Population & Acquired immunodeficiency syndrome (AIDS). The organization has 1341 authors who have published 1336 publications receiving 25018 citations.

Icosahedral viruses defined by their positively charged domains: a signature for viral identity and capsid assembly strategy

Abstract: Capsid proteins often present a positively charged arginine-rich region at the N and/or C-termini that for some icosahedral viruses has a fundamental role in genome packaging and particle stability. Even though Arginine-arms seem to be a common feature to many viruses, its occurrence and distribution across the protein universe are unknown. These sequences show little to no conservation at the amino-acid level and are structurally dynamic so that they cannot be detected by common sequence or structure comparison. We developed a methodology based on the net charge calculation of discrete segments of the protein sequence that allows us to identify proteins containing amino-acid stretches with an extremely high net charge. We observed that among all organisms, icosahedral viruses are especially enriched in extremely positively charged segments (Q [≥] +16), with a different bias towards arginine instead of lysine. We used viral particle structural data to calculate the total electrostatic charge derived from the most positively charged protein segment of capsid proteins and correlated these values with genome charge arising from the phosphates of each base. We obtained a positive correlation (r = 0.91, p-value < 0001) for a group of 17 viral families, corresponding to 40% of all families with icosahedral structures described so far. These data indicated that unrelated viruses with diverse genome types adopt a common underlying mechanism for capsid assembly and genome stabilization based on R-arms. A simple linear fit identified other virus families as outliers, pointing to alternative strategies of capsid assembly and genome packaging.nnSignificance StatementViruses can be characterized by the existence of a capsid, an intricate proteinaceous container that encases the viral genome. Therefore, capsid assembly and function are essential to viral replication. Here we show that for many virus families with diverse capsid structure and sequence, capsid packing capacity depends on a distinctive structural feature: a highly positively charged segment of amino acids residues, preferentially made of arginine. We also show that proteins with the same characteristics are rarely found in cellular proteins. Therefore, we identified a conserved viral functional element that can be used to infer capsid assembly mechanisms and inspire the design of new, much needed, broad-spectrum antiviral treatments.

A Buck Converter with Integrated Circuit Breaker

Abstract: Power conversion and protection systems are often associated with two different devices; power electronic converters and circuit breakers. With power electronic converters enabling the integration of various dc sources, and circuit breakers providing system protection, both are essential in the reliability of dc networks. This paper introduces a non-isolated dc-dc power converter with integrated circuit breaker, able to simultaneously provide power conversion, and fault current limiting and interruption capabilities. The proposed system's topology, based on the series coupled inductor Z-Source Circuit Breaker (S-C-ZCB), inherits its automatic ability to limit fault currents and low-pass filter characteristic while reducing its footprint, operational and maintenance cost over traditional dc circuit breakers. Analysis of the proposed system, along with simulation results, are presented and compared during both steady-state operation and a fault on the output terminal.

Adjunctive yoga training for persons with schizophrenia: who benefits?

Abstract: Objective: The aim of this study was to identify factors associated with acceptability and efficacy of yoga training (YT) for improving cognitive dysfunction in individuals with schizophrenia (SZ). Methods: We analysed data from two published clinical trials of YT for cognitive dysfunction among Indians with SZ: (1) a 21-day randomised controlled trial (RCT, N = 286), 3 and 6 months follow-up and (2) a 21-day open trial (n = 62). Multivariate analyses were conducted to examine the association of baseline characteristics (age, sex, socio-economic status, educational status, duration, and severity of illness) with improvement in cognition (i.e. attention and face memory) following YT. Factors associated with acceptability were identified by comparing baseline demographic variables between screened and enrolled participants as well as completers versus non-completers. Results: Enrolled participants were younger than screened persons who declined participation (t = 2.952, p = 0.003). No other characteristics were associated with study enrollment or completion. Regarding efficacy, schooling duration was nominally associated with greater and sustained cognitive improvement on a measure of facial memory. No other baseline characteristics were associated with efficacy of YT in the open trial, the RCT, or the combined samples (n = 148). Conclusions: YT is acceptable even among younger individuals with SZ. It also enhances specific cognitive functions, regardless of individual differences in selected psychosocial characteristics. Thus, yoga could be incorporated as adjunctive therapy for patients with SZ. Importantly, our results suggest cognitive dysfunction is remediable in persons with SZ across the age spectrum.