108 research outputs found
Status of soil-transmitted helminth infections in schoolchildren in Laguna Province, the Philippines: Determined by parasitological and molecular diagnostic techniques
Background
Soil-transmitted helminths (STH) are the most common parasitic infections in impoverished communities, particularly among children. Current STH control is through school-based mass drug administration (MDA), which in the Philippines is done twice annually. As expected, MDA has decreased the intensity and prevalence of STH over time. As a result, the common Kato Katz (KK) thick smear method of detecting STH is less effective because it lacks sensitivity in low intensity infections, making it difficult to measure the impact of deworming programs.
Methodology/Principal findings
A cross-sectional study was carried out over a four-week period from October 27, 2014 until November 20, 2014 in Laguna province, the Philippines. Stool samples were collected from 263 schoolchildren, to determine the prevalence of STH and compare diagnostic accuracy of multiplex quantitative polymerase chain reaction (qPCR) with the KK. A large discrepancy in the prevalence between the two techniques was noted for the detection of at least one type of STH infection (33.8% by KK vs. 78.3% by qPCR), Ascaris lumbricoides (20.5% by KK vs. 60.8% by qPCR) and Trichuris trichiura (23.6% by KK vs. 38.8% by qPCR). Considering the combined results of both methods, the prevalence of at least one type of helminth infection, A. lumbricoides, and T. trichiura were 83.3%, 67.7%, and 53.6%, respectively. Sensitivity of the qPCR for detecting at least one type of STH infection, A. lumbricoides, and T. trichiura were 94.1%, 89.9%, and 72.3% respectively; whereas KK sensitivity was 40.6%, 30.3%, and 44.0%, respectively. The qPCR method also detected infections with Ancylostoma spp. (4.6%), Necator americanus (2.3%), and Strongyloides stercoralis (0.8%) that were missed by KK.
Conclusion/Significance
qPCR may provide new and important diagnostic information to improve assessment of the effectiveness and impact of integrated control strategies particularly in areas where large-scale STH control has led to low prevalence and/or intensity of infection.This work is funded by a National Health
and Medical Research Council (NHMRC) Australia,
project grant (1046901); and the UBS-Optimus
Foundation Switzerland. DJG is an Australian
NHMRC Career Development Fellow; ACAC is an
Australian NHMRC Senior Research Fellow; DPM is
an Australian NHMRC Senior Principal Research Fellow
Pranolium
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72226/1/j.1527-3466.1983.tb00447.x.pd
Wall fluxes of reactive oxygen species of an rf atmospheric-pressure plasma and their dependence on sheath dynamics
This article was published in the serial, Journal of Physics D: Applied Physics [© IOP Publishing Ltd]. The definitive version is available at: http://dx.doi.org/10.1088/0022-3727/45/30/305205A radio-frequency (rf) atmospheric-pressure discharge in He–O2 mixture is studied using a
fluid model for its wall fluxes and their dependence on electron and chemical kinetics in the
sheath region. It is shown that ground-state O, O+2 and O− are the dominant wall fluxes of
neutral species, cations and anions, respectively. Detailed analysis of particle transport shows
that wall fluxes are supplied from a boundary layer of 3–300μm immediately next to an
electrode, a fraction of the thickness of the sheath region. The width of the boundary layer
mirrors the effective excursion distance during lifetime of plasma species, and is a result of
much reduced length scale of particle transport at elevated gas pressures. As a result, plasma
species supplying their wall fluxes are produced locally within the boundary layer and the
chemical composition of the overall wall flux depends critically on spatio-temporal
characteristics of electron temperature and density within the sheath. Wall fluxes of cations
and ions are found to consist of a train of nanosecond pulses, whereas wall fluxes of neutral
species are largely time-invariant
Measurement of right ventricular end-systolic and end-diastolic volumes by the thermodilution technique.
At the present time there is no entirely satisfactory index of ventricular function. End-diastolic pres-sure is often used as it can be relatively easily mea-sured and, with other factors, is related to the length of myocardial fibres at the end of diastole. Ven-tricular end-diastolic volume (EDV) is, however, a much closer approximation of fibre length, because, as Starling and Visscher (1927) have shown, it determines the force of subsequent ventricular contraction and the stroke volume (SV). End-systolic volume (ESV) and the ratio ESV/EDV are also indicators of ventricular functional capacity. Early attempts to measure heart volumes were made using measurements from x-rays (Rohrer, 1916
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