4,642 research outputs found
Kawasaki disease: the role of immune complexes revisited
Kawasaki disease (KD) is an inflammatory disease in children associated with vasculitis affecting predominantly the coronary arteries and is now the most common cause of acquired heart disease in children in developed countries. The etiology of KD is unknown but epidemiological studies implicate an infectious agent or toxin, which causes disease in genetically predisposed individuals. The presence of immune complexes (ICs) in the serum of children with KD was established in numerous studies during the 1970s and 80s. More recent genetic studies have identified variation in Fcγ receptors and genes controlling immunoglobulin production associated with KD. In this review we link the genetic findings and IC studies and suggest a key role for their interaction in pathophysiology of the disease
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Calibration of an optical fibre cerebral oximeter using a Monte Carlo model
Macro- and micro-strain in GaN nanowires on Si(111)
We analyze the strain state of GaN nanowire ensembles by x-ray diffraction.
The nanowires are grown by molecular beam epitaxy on a Si(111) substrate in a
self-organized manner. On a macroscopic scale, the nanowires are found to be
free of strain. However, coalescence of the nanowires results in micro-strain
with a magnitude from +-0.015% to +-0.03%.This micro-strain contributes to the
linewidth observed in low-temperature photoluminescence spectra
Grassland Management–The PROGRAZE™ Approach
Three courses PROGRAZE™, PROGRAZE™ Plus and STOCKPLAN® have been developed to provide a complete package to assist farmers manage their variable grassland grazing systems. As each package is separate the farmer can use the relevant tool to help them work through major issues they are dealing with at any point in time. All courses are based on the same principle, they do not give answers but rather provide training in skills development, provide key background knowledge and a framework to assist farmers plan and if needed to work through their problems to reach a solution they are comfortable with
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Estimation of instantaneous venous blood saturation using the Photoplethysmograph (PPG) waveform
Non-invasive estimation of regional venous saturation (SxvO2) using a conventional pulse oximeter could provide a means of obtaining clinically relevant information. This study was carried out in order to investigate the hypothesis that SxvO2 could be estimated by utilising the modulations created by positive pressure ventilation in the photoplethysmograph (PPG) signals. The modulations caused by the mechanical ventilator were extracted from oesophageal PPG signals obtained from 12 patients undergoing cardiothoracic surgery. The signals analysed in this work were acquired in a previous study. For the purpose of this analysis the raw PPG signal was considered to have three major components, ac PPG signal (cardiac related component), a static component or dc PPG signal (created mostly by the absorption of light by surrounding tissue) and the ventilator modulation component. These components were then used to estimate instantaneous arterial blood oxygen saturation (SpO2) and SxvO2 by utilising time-frequency analysis technique of smoothed-pseudo Wigner–Ville distribution (SPWVD). The results showed that there was no significant difference in the traditionally-derived (time-domain) arterial saturation and the instantaneous arterial saturation. However, the instantaneous venous saturation was found to be significantly lower than the estimated time-domain and instantaneous arterial saturation (P=<0.001, n=12)
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Preliminary evaluation of a new fibre-optic cerebral oximetry system
A new system for measuring the oxygen saturation of blood within tissue has been developed, for a variety of patient monitoring applications. A particular unmet need is in the central nervous system, and this project aims to devise a means for measuring blood oxygen saturation in the brain tissue of patients recovering from neurosurgery or head injury. Coupling light sources and a photodetector to optical fibres results in a probe small enough to pass through a cranial bolt of the type already in use for intra-cranial pressure monitoring. The development and evaluation of a two-wavelength fibre-optic reflectance photoplethysmography (PPG) system are described. It was found that good quality red and near-infrared PPG signals could be obtained from the finger using a fibre-optic probe. Experiments were conducted to find the inter-fibre spacings that yield signals most suitable for calculating oxygen saturation. Reliable signals could be obtained for inter-fibre spacings between 2 mm and 5 mm, the latter being the size of the maximum aperture in the cranial bolt. A preliminary measurement from human brain tissue is also presented
Late-onset bloodstream infection and perturbed maturation of the gastrointestinal microbiota in premature infants
Late-onset bloodstream infection (LO-BSI) is a common complication of prematurity, and lack of timely diagnosis and treatment can have life-threatening consequences. We sought to identify clinical characteristics and microbial signatures in the gastrointestinal microbiota preceding diagnosis of LO-BSI in premature infants.Daily faecal samples and clinical data were collected over two years from 369 premature neonates (<32 weeks gestation). We analysed samples from 22 neonates who developed LO-BSI and 44 matched control infants. Next-generation sequencing of 16S rRNA gene regions amplified by PCR from total faecal DNA was used to characterise the microbiota of faecal samples preceding diagnosis from infants with LO-BSI and controls. Culture of selected samples was undertaken, and bacterial isolates identified using MALDI-TOF. Antibiograms from bloodstream and faecal isolates were compared to explore strain similarity.From the week prior to diagnosis, infants with LO-BSI had higher proportions of faecal aerobes/facultative anaerobes compared to controls. Risk factors for LO-BSI were identified by multivariate analysis. Enterobacteriaceal sepsis was associated with antecedent multiple lines, low birth weight and a faecal microbiota with prominent Enterobacteriaceae. Staphylococcal sepsis was associated with Staphylococcus OTU faecal over-abundance, and the number of days prior to diagnosis of mechanical ventilation and of the presence of centrally-placed lines. In 12 cases, the antibiogram of the bloodstream isolate matched that of a component of the faecal microbiota in the sample collected closest to diagnosis.The gastrointestinal tract is an important reservoir for LO-BSI organisms, pathogens translocating across the epithelial barrier. LO-BSI is associated with an aberrant microbiota, with abundant staphylococci and Enterobacteriaceae and a failure to mature towards predominance of obligate anaerobes
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Basin-Fill Stratigraphy, Quaternary History, and Paleomagnetics of the Eagle Flat Study Area, Southern Hudspeth County, Texas
Data and analyses of basin-fill stratigraphy, paleomagnetics, Quaternary history, and pseudo-fissures/fissures were acquired and interpreted by the Bureau of Economic Geology (BEG) in the Eagle Flat study area in southern Hudspeth County, Texas. These investigations were funded by the Texas Low-Level Radioactive Waste Disposal Authority (the Authority) as part of the evaluation of a proposed site for the Texas low-level radioactive waste repository. Data and information developed as a result of these investigations will be used to evaluate the proposed waste repository site and surrounding region and to provide data for performance assessment, design, and licensing activities. Basin-fill sediments are composed predominantly of sandy mud and mud; sands are abundant at the surface in the vicinity of the proposed repository site, and gravels are abundant at the base of the basin fill adjacent to the bedrock. Basin-fill thickness ranges from 163 ft (50 m) on the southeast side of the proposed site to 715 ft (218 m) on the northeast side of the proposed site. Basin-fill thickness is approximately 200 ft (61 m) on the west side of the proposed site. Coarser basin-fill deposits are interpreted as proximal alluvial fans and colluvium, and finer sands and muds are interpreted as ephemeral stream, distal alluvial fan, alluvial flat, and eolian deposits. At the proposed site, near-surface fine gravel and coarse to fine sand deposits exhibit characteristics consistent with fluvial deposition. Some well-sorted fine-grained sands have textures consistent with eolian sediments. Fine-grained sands and muds are interpreted as distal alluvial fan and ephemeral stream deposits.Bureau of Economic Geolog
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Optical fibre catheter photoplethysmograph
A fibre optic system for monitoring arterial oxygen saturation of internal tissue sites utilising the principle of reflectance pulse oximetry is being developed. It was shown that it is possible to obtain a stable photoplethysmograph (PPG) signal from the fingertip using a twin optical fibre catheter. The results of experiments to optimise the detection of PPG signals using optical fibres are presented. Possible applications of this method include measuring SpO2 in the oesophagus, trachea, large intestine, brain tissue and spinal cord
Experimental demonstration of Shor's algorithm with quantum entanglement
Shor's powerful quantum algorithm for factoring represents a major challenge
in quantum computation and its full realization will have a large impact on
modern cryptography. Here we implement a compiled version of Shor's algorithm
in a photonic system using single photons and employing the non-linearity
induced by measurement. For the first time we demonstrate the core processes,
coherent control, and resultant entangled states that are required in a
full-scale implementation of Shor's algorithm. Demonstration of these processes
is a necessary step on the path towards a full implementation of Shor's
algorithm and scalable quantum computing. Our results highlight that the
performance of a quantum algorithm is not the same as performance of the
underlying quantum circuit, and stress the importance of developing techniques
for characterising quantum algorithms.Comment: 4 pages, 5 figures + half-page additional online materia
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