20 research outputs found
Mass deworming for improving health and cognition of children in endemic helminth areas: A systematic review and individual participant data network metaâanalysis
BackgroundSoil transmitted (or intestinal) helminths and schistosomes affect millions of children worldwide.ObjectivesTo use individual participant data network metaâanalysis (NMA) to explore the effects of different types and frequency of deworming drugs on anaemia, cognition and growth across potential effect modifiers.Search MethodsWe developed a search strategy with an information scientist to search MEDLINE, CINAHL, LILACS, Embase, the Cochrane Library, Econlit, Internet Documents in Economics Access Service (IDEAS), Public Affairs Information Service (PAIS), Social Services Abstracts, Global Health CABI and CAB Abstracts up to March 27, 2018. We also searched grey literature, websites, contacted authors and screened references of relevant systematic reviews.Selection CriteriaWe included randomised and quasirandomised deworming trials in children for deworming compared to placebo or other interventions with data on baseline infection.Data Collection and AnalysisWe conducted NMA with individual participant data (IPD), using a frequentist approach for randomâeffects NMA. The covariates were: age, sex, weight, height, haemoglobin and infection intensity. The effect estimate chosen was the mean difference for the continuous outcome of interest.ResultsWe received data from 19 randomized controlled trials with 31,945 participants. Overall risk of bias was low. There were no statistically significant subgroup effects across any of the potential effect modifiers. However, analyses showed that there may be greater effects on weight for moderate to heavily infected children (very low certainty evidence).Authors' ConclusionsThis analysis reinforces the case against mass deworming at a populationâlevel, finding little effect on nutritional status or cognition. However, children with heavier intensity infections may benefit more. We urge the global community to adopt calls to make data available in open repositories to facilitate IPD analyses such as this, which aim to assess effects for the most vulnerable individuals.</div
A Highly Active Low Voltage Redox Mediator for Enhanced Rechargeability of LithiumâOxygen Batteries
Owing to its high theoretical specific
energy, the Li-oxygen battery
is one of the fundamentally most promising energy storage systems,
but also one of the most challenging. Poor rechargeability, involving
the oxidation of insoluble and insulating lithium peroxide (Li<sub>2</sub>O<sub>2</sub>), has remained the âAchillesâ
heelâ of this electrochemical energy storage system. We report
here on a new redox mediator trisÂ[4-(diethylamino)Âphenyl]Âamine
(TDPA), thatî¸at 3.1 Vî¸exhibits the lowest and closest
potential redox couple compared to the equilibrium voltage of the
Li-oxygen cell of those reported to date, with a second couple also
at a low potential of 3.5 V. We show it is a soluble âcatalystâ
capable of lowering the Li<sub>2</sub>O<sub>2</sub> charging potential
by >0.8 V without requiring direct electrical contact of the peroxide
and that it also facilitates high discharge capacities. Its chemical
and electrochemical stability, fast diffusion kinetics, and two dynamic
redox potentials represent a significant advance in oxygen-evolution
catalysis. It enables LiâO<sub>2</sub> cells that can be recharged
more than 100 cycles with average round-trip efficiencies >80%,
opening
a new avenue for practical Li-oxygen batteries
MOESM1 of Cost-effectiveness analysis of the diarrhea alleviation through zinc and oral rehydration therapy (DAZT) program in rural Gujarat India: an application of the net-benefit regression framework
Additional file 1: Table S1. DAZT intervention components according to activity in Gujarat
Nanostructured Metal Carbides for Aprotic LiâO<sub>2</sub> Batteries: New Insights into Interfacial Reactions and Cathode Stability
The development of nonaqueous Liâoxygen
batteries, which
relies on the reversible reaction of Li + O<sub>2</sub> to give lithium
peroxide (Li<sub>2</sub>O<sub>2</sub>), is challenged by several factors,
not the least being the high charging voltage that results when carbon
is typically employed as the cathode host. We report here on the remarkably
low 3.2 V potential for Li<sub>2</sub>O<sub>2</sub> oxidation on a
passivated nanostructured metallic carbide (Mo<sub>2</sub>C), carbon-free
cathode host. Online mass spectrometry coupled with X-ray photoelectron
spectroscopy unequivocally demonstrates that lithium peroxide is simultaneously
oxidized together with the Li<sub><i>x</i></sub>MoO<sub>3</sub>-passivated conductive interface formed on the carbide, owing
to their close redox potentials. The process rejuvenates the surface
on each cycle upon electrochemical charge by releasing Li<sub><i>x</i></sub>MoO<sub>3</sub> into the electrolyte, explaining
the low charging potential
Screening for Superoxide Reactivity in Li-O<sub>2</sub> Batteries: Effect on Li<sub>2</sub>O<sub>2</sub>/LiOH Crystallization
Unraveling the fundamentals of Li-O<sub>2</sub> battery
chemistry
is crucial to develop practical cells with energy densities that could
approach their high theoretical values. We report here a straightforward
chemical approach that probes the outcome of the superoxide O<sub>2</sub><sup>â</sup>, thought to initiate the electrochemical
processes in the cell. We show that this serves as a good measure
of electrolyte and binder stability. Superoxide readily dehydrofluorinates
polyvinylidene to give byproducts that react with catalysts to produce
LiOH. The Li<sub>2</sub>O<sub>2</sub> product morphology is a function
of these factors and can affect Li-O<sub>2</sub> cell performance.
This methodology is widely applicable as a probe of other potential
cell components
The Importance of Nanometric Passivating Films on Cathodes for LiâAir Batteries
Recently, there has been a transition from fully carbonaceous positive electrodes for the aprotic lithium oxygen battery to alternative materials and the use of redox mediator additives, in an attempt to lower the large electrochemical overpotentials associated with the charge reaction. However, the stabilizing or catalytic effect of these materials can become complicated due to the presence of major side-reactions observed during dis(charge). Here, we isolate the charge reaction from the discharge by utilizing electrodes prefilled with commercial lithium peroxide with a crystallite size of about 200â800 nm. Using a combination of S/TEM, online mass spectrometry, XPS, and electrochemical methods to probe the nature of surface films on carbon and conductive Ti-based nanoparticles, we show that oxygen evolution from lithium peroxide is strongly dependent on their surface properties. Insulating TiO<sub>2</sub> surface layers on TiC and TiN - even as thin as 3 nmâcan completely inhibit the charge reaction under these conditions. On the other hand, TiC, which lacks this oxide film, readily facilitates oxidation of the bulk Li<sub>2</sub>O<sub>2</sub> crystallites, at a much lower overpotential relative to carbon. Since oxidation of lithium oxygen battery cathodes is inevitable in these systems, precise control of the surface chemistry at the nanoscale becomes of upmost importance
Accuracy of Vital Rate Estimates using RMM community-based method in each setting, compared to estimates derived from full birth histories collected through a sample survey or census
<p>Accuracy of Vital Rate Estimates using RMM community-based method in each setting, compared to estimates derived from full birth histories collected through a sample survey or census</p
Implementation Timeline of RMM Community-based Method by Country Setting.
<p>Implementation Timeline of RMM Community-based Method by Country Setting.</p
Average sex ratio at birth for RMM data collected by community-based health workers compared with those from comparable full pregnancy histories for annualized periods
<p>Average sex ratio at birth for RMM data collected by community-based health workers compared with those from comparable full pregnancy histories for annualized periods</p
Reporting Completeness of Vital Events Information by CHBWs relative to the expected number of events estimated from full pregnancy histories collected through a sample survey or census
<p>Reporting Completeness of Vital Events Information by CHBWs relative to the expected number of events estimated from full pregnancy histories collected through a sample survey or census</p