289 research outputs found
Examining the effects of HIV self-testing compared to standard HIV testing services in the general population: A systematic review and meta-analysis
BACKGROUND: We updated a 2017 systematic review and compared the effects of HIV self-testing (HIVST) to standard HIV testing services to understand effective service delivery models among the general population.
METHODS: We included randomized controlled trials (RCTs) comparing testing outcomes with HIVST to standard testing in the general population and published between January 1, 2006 and June 4, 2019. Random effects meta-analysis was conducted and pooled risk ratios (RRs) were reported. The certainty of evidence was determined using the GRADE methodology.
FINDINGS: We identified 14 eligible RCTs, 13 of which were conducted in sub-Saharan Africa. Support provided to self-testers ranged from no/basic support to one-on-one in-person support. HIVST increased testing uptake overall (RR:2.09; 95% confidence interval: 1.69-2.58;
INTERPRETATION: HIVST appears to be safe and effective among the general population in sub-Saharan Africa with a range of delivery models. It identified and linked additional people with HIV to care. These findings support the wider availability of HIVST to reach those who may not otherwise access testing
Globrauneine A–F: six new triterpenoid esters from the leaves of Globimetula braunii
Phytochemical study was conducted on the leaves of Globimetula braunii which is a hemi parasitic plant belonging to the family Loranthaceae. Extraction was carried out using cold extraction method with increasing polarity of solvents i.e n-hexane, CH2Cl2 and MeOH. The components were separated by chromatographic technique and the structures of the compounds were elucidated by extensive spectroscopic analyses including MS, FTIR, 1D and 2D NMR, HRMS and chemical methods. Six new pentacyclic triterpenoid esters named as globrauneine A (1), globrauneine B (2), globrauneine C (3), globrauneine D (4), globrauneine E (5), and globrauneine F (6), together with six known compounds (7 – 12) were successfully isolated from the leaves of G. braunii growing on Piliostigma thonningii. These results depict a substantial support to the chemotaxonomy of the genus Globimetula
Importance and Significance of UF/MF Membrane Systems in Desalination Water Treatment
The proposed chapter addresses a comprehensive overview of the history and future outlook of ultrafiltration/microfiltration (UF/MF) membrane for desalination water pretreatment. Known theories on UF/MF membrane formation from phase inversion (Dr/wet) systems can be prolonged to define the consequences of high or low molecular weight additives. Also, direct material reengineering and surface modification for high-performance anti-fouling of UF/MF membranes are also highlighted. Before the modern final polymeric film, the characterization techniques, particularly molecular weight cut-off, pore size, pore size distribution, and microbiological activity classification, on to the UF/MF membrane surface were presented, respectively. Lab scale to commercial scale UF/MF membrane configuration and market size of UF/MF membranes for pretreatment desalination are described. The significance of UF/MF provided here as an unconventional approach for desalination water pretreatment is in contrast with the current conventionally used technologies. The recent development made in the integration of established desalination processes, such as spiral wound reverse osmosis (SWRO), multi-stage flash (MSF), multi-effect distillation (MED), electrodialysis (ED) desalination, and UF pretreatment, is addressed. Finally, the influence of UF/MF on desalination water pretreatment step on to the energy cost of desalination process system is discussed
Complementarity of Semileptonic to and Decays in the Standard Model with Fourth Generation
The decays are
analyzed in the Standard Model extended to fourth generation of quarks (SM4).
The decay rate, forward-backward asymmetry, lepton polarization asymmetries and
the helicity fractions of the final state meson are obtained
using the form factors calculated in the light cone sum rules (LCSR) approach.
We have utilized the constraints on different fourth generation parameters
obtained from the experimental information on , and decays and from
the electroweak precision data to explore their impact on the decay. We find that the values of above mentioned
physical observables deviate deviate significantly from their minimal SM
predications. We also identify a number of correlations between various
observables in and decays. Therefore a combined analysis of these two
decays will compliment each other in the searches of SM4 effects in flavor
physics.Comment: 28 pages, 12 figure
Statefinder Parameter for Varying G in Three Fluid System
In this work, we have considered variable G in flat FRW universe filled with
the mixture of dark energy, dark matter and radiation. If there is no
interaction between the three fluids, the deceleration parameter and
statefinder parameters have been calculated in terms of dimensionless density
parameters which can be fixed by observational data. Also the interaction
between three fluids has been analyzed due to constant . The statefinder
parameters also calculated in two cases: pressure is constant and pressure is
variable.Comment: 5 pages, Accepted for publication in "Astrophysics and Space Science
Reconstruction of some cosmological models in f(R,T) gravity
In this paper, we reconstruct cosmological models in the framework of
gravity, where is the Ricci scalar and is the trace of the
stress-energy tensor. We show that the dust fluid reproduces CDM,
phantom-non-phantom era and the phantom cosmology. Further, we reconstruct
different cosmological models including, Chaplygin gas, scalar field with some
specific forms of . Our numerical simulation for Hubble parameter shows
good agreement with the BAO observational data for low redshifts .Comment: 12 pages, 2 figure
Country adherence to WHO recommendations to improve the quality of HIV diagnosis: a global policy review.
INTRODUCTION: Ensuring a correct and timely HIV diagnosis is critical. WHO publishes guidelines on HIV testing strategies that maximise the likelihood of correctly determining one's HIV status. A review of national HIV testing policies in 2014 found low adherence to WHO guidelines. We updated this review to determine adherence to current recommendations. METHODS: We conducted a comprehensive policy review through April 2018. We extracted data on HIV testing strategies, recommendations on HIV retesting prior to antiretroviral therapy (ART) initiation and pre-exposure prophylaxis (PrEP)-related HIV testing information. Descriptive analyses disaggregated by region were conducted to ascertain adherence to recommendations and to describe testing strategy characteristics. RESULTS: Of 91 policies included, 26% (n=24/91) adhered to WHO recommendations. Having a two-assay testing strategy to rule-in HIV infection as opposed to the recommended three-assay testing strategy was a major reason for non-adherence. Of 72 country policies providing sufficient information, 31% (n=22) recommended retesting for HIV prior to initiating ART. Of 25 countries and two regions reporting PrEP-related HIV testing guidelines, almost all recommended testing prior to initiating PrEP and every 3 months during PrEP use. CONCLUSIONS: Global adherence to WHO recommendations for HIV testing strategies have improved since 2014 but remain low. We found adherence existed on a continuum. Such a system provides insights into how countries can move towards adherence by making relatively minor changes to testing strategies. Guidance from WHO on the role of new HIV testing technologies within testing algorithms and identifying ways to simplify testing guidance is warranted
Exergoeconomic optimization of a shell-and-tube heat exchanger
The paper presents an economic optimization of a STHX with two commonly adopted (i.e., Kern and Bell-Delaware) and one rarely explored (i.e., Wills-Johnston) methods. A detailed numerical code concerning thermal, hydraulic, exergy, and economic analysis of STHX is developed for all three methods. Normalized sensitivity analysis, parametric study, and Genetic Algorithm are used to ascertain the most influential parameters and optimize the total cost. It is observed that the calculations made using the Wills-Johnston method were reasonably close to the Bell-Delaware method. While the Kern method showed a significant deviation in the shell side calculations because of the several assumptions in this method. The parametric analysis showed that increasing the mass flow rate and the number of baffles increased the operating cost because of an exponential increase in the pressure drops. Finally, the optimization reduced the heat transfer area by ~26.4%, capital cost by ~20%, operational cost by ~50%, total cost by ~22%, and the stream cost by ~21%
An efficient modulation technique to mitigate nonlinearities in optical OFDM
The optical OFDM (O-OFDM) system is a growing technology for next generation high-speed optical communication. Two types of O-OFDM; CO-OFDM (Coherent- Optical OFDM) and Direct-current-based optical OFDM (DCOFDM) are discussed. Mach–Zehnder modulators (MZMs) are used in up-converter part of CO-OFDM system to convert the RF signal to optical signal when the light cannot directly modulate for higher speed. The MZM has a cosine behavior with high nonlinear characteristic that affects the system performance. This paper aims to investigate an efficient pulse modulation
technique for mitigating nonlinearity effect in the Mach-Zehnder modulator of CO-OFDM system. It also highlights the proposed method, an efficient CO-OFDM system to solve the existing nonlinearity issue. This technique influences positively on OSNR to reduce non linearity over different distances of optical channel and improve the system performance in terms of power consumption and bandwidth efficiency
ESAT6-Induced IFNγ and CXCL9 Can Differentiate Severity of Tuberculosis
BACKGROUND: Protective responses against Mycobacterium tuberculosis are dependent on appropriate T cell and macrophage activation. Mycobacterial antigen six kDa early secreted antigenic target (ESAT6) and culture filtrate protein 10 (CFP10) can detect M. tuberculosis specific IFNgamma responses. However, most studies have been performed in non-endemic regions and to study pulmonary tuberculosis (PTB). We have studied ESAT6 and CFP10 induced cytokine and chemokines responses in PTB and extrapulmonary (EPul) TB. METHODOLOGY: IFNgamma, IL10, CXCL9 and CCL2 responses were determined using an ex vivo whole blood assay system in PTB (n = 30) and EPulTB patients with limited (LNTB, n = 24) or severe (SevTB, n = 22) disease, and in healthy endemic controls (ECs). Responses to bacterial LPS were also determined. PRINCIPAL FINDINGS: ESAT6- and CFP10-induced IFNgamma was comparable between ECs and TB patients. Both ESAT6- and CFP10-induced IFNgamma secretion was greater in LNTB than PTB. ESAT6-induced CXCL9 was greater in EPulTB as compared with PTB, with an increase in SevTB as compared with LNTB. CFP10-induced CCL2 was higher in PTB than LNTB patients. LPS-stimulated CXCL9 was greatest in SevTB and LPS-induced CCL2 was increased in PTB as compared with LNTB patients. A positive correlation between ESAT6-induced IFNgamma and CXCL9 was present in all TB patients, but IFNgamma and CCL2 was only correlated in LNTB. ESAT-induced CCL2 and CXCL9 were significantly associated in LNTB while correlation in response to LPS was only present in SevTB. CONCLUSIONS: ESAT6 induced IFNgamma and CXCL9 can differentiate between limited and severe TB infections
- …