142 research outputs found
Effectiveness of insecticide-treated bednets in malaria prevention in Haiti: a case-control study
Background Insecticide-treated bednets (ITNs) are eff ective in preventing malaria where vectors primarily bite indoors
and late at night, but their eff ectiveness is uncertain where vectors bite outdoors and earlier in the evening. We
studied the eff ectiveness of ITNs following a mass distribution in Haiti from May to September, 2012, where the
Anopheles albimanus vector bites primarily outdoors and often when people are awake.
Methods In this case-control study, we enrolled febrile patients presenting to outpatient departments at 17 health
facilities throughout Haiti from Sept 4, 2012, to Feb 27, 2014, who were tested with malaria rapid diagnostic
tests (RDTs), and administered questionnaires on ITN use and other risk factors. Cases were defi ned by positive RDT
and controls were febrile patients from the same clinic with a negative RDT. Our primary analysis retrospectively
matched cases and controls by age, sex, location, and date, and used conditional logistic regression on the matched
sample. A sensitivity analysis used propensity scores to match patients on ITN use propensity and analyse malaria
among ITN users and non-users. Additional ITN bioeffi cacy and entomological data were collected.
Findings We enrolled 9317 patients, including 378 (4%) RDT-positive cases. 1202 (13%) patients reported ITN use.
Post-hoc matching of cases and controls yielded 362 cases and 1201 matched controls, 19% (333) of whom reported
consistent campaign net use. After using propensity scores to match on consistent campaign ITN use, 2298 patients,
including 138 (7%) RDT-positive cases, were included: 1149 consistent campaign ITN users and 1149 non-consistent
campaign ITN users. Both analyses revealed that ITNs did not signifi cantly protect against clinical malaria
(odds ratio [OR]=0·95, 95% CI 0·68–1·32, p=0·745 for case-control analysis; OR=0·95, 95% CI 0·45–1·97, p=0·884
for propensity score analysis). ITN and entomological data indicated good ITN physical integrity and bioeffi cacy, and
no permethrin resistance among local mosquitoes.
Interpretation We found no evidence that mass ITN campaigns reduce clinical malaria in this observational study in
Haiti; alternative malaria control strategies should be prioritised
The First Definitive Binary Orbit Determined with the Hubble Space Telescope Fine Guidance Sensors: Wolf 1062 (Gliese 748)
The M dwarf binary, Wolf 1062 (Gliese 748), has been observed with the Hubble Space Telescope (HST) Fine Guidance Sensor 3 in the transfer function scan mode to determine the apparent orbit. This is the first orbit defined fully and exclusively with HST, and is the most accurate definitive orbit for any resolved, noneclipsing system. The orbital period is 2.4490 ± 0.0119 yr and the semimajor axis is 01470 ± 00007—both quantities are now known to better than 1%. Using the weighted mean of seven parallax measurements and these HST data, we find the system mass to be 0.543 ± 0.031 M⊙, where the error of 6% is due almost entirely to the parallax error. An estimated fractional mass from the infrared brightness ratio and infrared mass-luminosity relation yields a mass for the primary of 0.37 M⊙, and the secondary falls in the regime of very low mass stars, with a mass of only 0.17 M⊙
Mode of action of DNA-competitive small molecule inhibitors of tyrosyl DNA phosphodiesterase 2
TDP2 is a 5’-tyrosyl DNA phosphodiesterase important for the repair of DNA adducts generated by non-productive (abortive) activity of topoisomerase II. TDP2 facilitates therapeutic resistance to topoisomerase poisons, which are widely used in the treatment of a range of cancer types. Consequently, TDP2 is an interesting target for the development of small molecule inhibitors that could restore sensitivity to topoisomerase-directed therapies. Previous studies identified a class of deazaflavin-based molecules that showed inhibitory activity against TDP2 at therapeutically useful concentrations, but their mode of action was uncertain. We have confirmed that the deazaflavin series inhibits TDP2 enzyme activity in a fluorescence-based assay, suitable for HTS-screening. We have gone on to determine crystal structures of these compounds bound to a ‘humanised’ form of murine TDP2. The structures reveal their novel mode of action as competitive ligands for the binding site of an incoming DNA substrate, and point the way to generating novel and potent inhibitors of TDP2
Status of Muon Collider Research and Development and Future Plans
The status of the research on muon colliders is discussed and plans are
outlined for future theoretical and experimental studies. Besides continued
work on the parameters of a 3-4 and 0.5 TeV center-of-mass (CoM) energy
collider, many studies are now concentrating on a machine near 0.1 TeV (CoM)
that could be a factory for the s-channel production of Higgs particles. We
discuss the research on the various components in such muon colliders, starting
from the proton accelerator needed to generate pions from a heavy-Z target and
proceeding through the phase rotation and decay ()
channel, muon cooling, acceleration, storage in a collider ring and the
collider detector. We also present theoretical and experimental R & D plans for
the next several years that should lead to a better understanding of the design
and feasibility issues for all of the components. This report is an update of
the progress on the R & D since the Feasibility Study of Muon Colliders
presented at the Snowmass'96 Workshop [R. B. Palmer, A. Sessler and A.
Tollestrup, Proceedings of the 1996 DPF/DPB Summer Study on High-Energy Physics
(Stanford Linear Accelerator Center, Menlo Park, CA, 1997)].Comment: 95 pages, 75 figures. Submitted to Physical Review Special Topics,
Accelerators and Beam
IL-2 Immunotherapy to Recently HIV-1 Infected Adults Maintains the Numbers of IL-17 Expressing CD4+ T (TH17) Cells in the Periphery
Little is known about the manipulation of IL-17 producing CD4+ T cells (TH17) on a per-cell basis in humans in vivo. Previous studies on the effects of IL-2 on IL-17 secretion in non-HIV models have shown divergent results. We hypothesized that IL-2 would mediate changes in IL-17 levels among recently HIV-1-infected adults receiving anti-retroviral therapy. We measured cytokine T cell responses to CD3/CD28, HIV-1 Gag, and CMV pp65 stimulation, and changes in multiple CD4+ T cell subsets. Those who received IL-2 showed a robust expansion of naive and total CD4+ T cell counts and T-reg counts. However, after IL-2 treatment, the frequency of TH17 cells declined, while counts of TH17 cells did not change due to an expansion of the CD4+ naïve T cell population (CD27+CD45RA+). Counts of HIV-1 Gag-specific T cells declined modestly, but CMV pp65 and CD3/CD28 stimulated populations did not change. Hence, in contrast with recent studies, our results suggest IL-2 is not a potent in vivo regulator of TH17 cell populations in HIV-1 disease. However, IL-2-mediated T-reg expansions may selectively reduce responses to certain antigen-specific populations, such as HIV-1 Gag
Consensus recommendations on the use of 18F-FDG PET/CT in lung disease
Positron emission tomography (PET) with 18F-fluorodeoxyglucose (18F-FDG)
has been increasingly applied, predominantly in the research setting,
to study drug effects and pulmonary biology and
monitor disease progression and treatment outcomes
in lung diseases, disorders that interfere with gas exchange through
alterations
of the pulmonary parenchyma, airways and/or
vasculature. To date, however, there are no widely accepted standard
acquisition
protocols and imaging data analysis methods for
pulmonary 18F-FDG PET/CT in these diseases, resulting in
disparate approaches. Hence, comparison of data across the literature is
challenging.
To help harmonize the acquisition and analysis and
promote reproducibility, acquisition protocol and analysis method
details
were collated from seven PET centers. Based on
this information and discussions among the authors, the consensus
recommendations
reported here on patient preparation, choice of
dynamic versus static imaging, image reconstruction, and image analysis
reporting
were reached.
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Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus
A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk
The Athena X-ray Integral Field Unit: a consolidated design for the system requirement review of the preliminary definition phase
The Athena X-ray Integral Unit (X-IFU) is the high resolution X-ray
spectrometer, studied since 2015 for flying in the mid-30s on the Athena space
X-ray Observatory, a versatile observatory designed to address the Hot and
Energetic Universe science theme, selected in November 2013 by the Survey
Science Committee. Based on a large format array of Transition Edge Sensors
(TES), it aims to provide spatially resolved X-ray spectroscopy, with a
spectral resolution of 2.5 eV (up to 7 keV) over an hexagonal field of view of
5 arc minutes (equivalent diameter). The X-IFU entered its System Requirement
Review (SRR) in June 2022, at about the same time when ESA called for an
overall X-IFU redesign (including the X-IFU cryostat and the cooling chain),
due to an unanticipated cost overrun of Athena. In this paper, after
illustrating the breakthrough capabilities of the X-IFU, we describe the
instrument as presented at its SRR, browsing through all the subsystems and
associated requirements. We then show the instrument budgets, with a particular
emphasis on the anticipated budgets of some of its key performance parameters.
Finally we briefly discuss on the ongoing key technology demonstration
activities, the calibration and the activities foreseen in the X-IFU Instrument
Science Center, and touch on communication and outreach activities, the
consortium organisation, and finally on the life cycle assessment of X-IFU
aiming at minimising the environmental footprint, associated with the
development of the instrument. Thanks to the studies conducted so far on X-IFU,
it is expected that along the design-to-cost exercise requested by ESA, the
X-IFU will maintain flagship capabilities in spatially resolved high resolution
X-ray spectroscopy, enabling most of the original X-IFU related scientific
objectives of the Athena mission to be retained. (abridged).Comment: 48 pages, 29 figures, Accepted for publication in Experimental
Astronomy with minor editin
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