1,095 research outputs found
Validation of a fornix depth measurer: a putative tool for the assessment of progressive cicatrising conjunctivitis
Background/aims Documentation of conjunctival forniceal foreshortening in cases of progressive cicatrising conjunctivitis (PCC) is important in ascertaining disease stage and progression. Lower fornix shortening is often documented subjectively or semi-objectively, whereas upper forniceal obliteration is seldom quantified. Although tools such as fornix depth measurers (FDMs) have been described, their designs limit upper fornix measurement. The purpose of this study was to custom-design a FDM to evaluate the upper fornix and to assess variability in gauging fornix depth. \ud
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Methods A polymethylmethacrylate FDM was constructed using industry-standard jewellery computer software and machinery. Two observers undertook a prospective independent evaluation of central lower fornix depth in a heterogeneous cohort of patients with clinically normal and abnormal conjunctival fornices both subjectively and by using the FDM (in mm). Upper central fornix depth was also measured. Agreement was assessed using Bland–Altman plots. \ud
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Results Fifty-one eyes were evaluated. There was 100% intraobserver agreement to within 1 mm for each observer for lower fornix measurement. The mean difference in fornix depth loss using the FDM between observer 1 and 2 was 1.19%, with 95% confidence of agreement (±2SD) of −15% to +20%. In total, 86% (44/51) of measurements taken by the two observers agreed to within 10% of total lower fornix depth (ie, ±1 mm) versus only 63% (32/51) of the subjective measurements. Mean upper fornix difference was 0.57 mm, with 95% confidence of agreement of between −2 and + 3 mm. \ud
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Conclusions This custom-designed FDM is well tolerated by patients and shows low intraobserver and interobserver variability. This enables repeatable and reproducible measurement of upper and lower fornix depths, facilitating improved rates of detection and better monitoring of progression of conjunctival scarring
Functional genomics to identify the factors contributing to successful persistence and global spread of an antibiotic resistance plasmid
Background: The spread of bacterial plasmids is an increasing global problem contributing to the widespread dissemination of antibiotic resistance genes including β-lactamases. Our understanding of the details of the biological mechanisms by which these natural plasmids are able to persist in bacterial populations and are able to establish themselves in new hosts via conjugative transfer is very poor. We recently identified and sequenced a globally successful plasmid, pCT, conferring β-lactam resistance. Results: Here, we investigated six plasmid encoded factors (tra and pil loci; rci shufflon recombinase, a putative sigma factor, a putative parB partitioning gene and a pndACB toxin-antitoxin system) hypothesised to contribute to the 'evolutionary success' of plasmid pCT. Using a functional genomics approach, the role of these loci was investigated by systematically inactivating each region and examining the impact on plasmid persistence, conjugation and bacterial host biology. While the tra locus was found to be essential for all pCT conjugative transfer, the second conjugation (pil) locus was found to increase conjugation frequencies in liquid media to particular bacterial host recipients (determined in part by the rci shufflon recombinase). Inactivation of the pCT pndACB system and parB did not reduce the stability of this plasmid. Conclusions: Our findings suggest the success of pCT may be due to a combination of factors including plasmid stability within a range of bacterial hosts, a lack of a fitness burden and efficient transfer rates to new bacterial hosts rather than the presence of a particular gene or phenotype transferred to the host. The methodology used in our study could be applied to other 'successful' globally distributed plasmids to discover the role of currently unknown plasmid backbone genes or to investigate other factors which allow these elements to persist and spread
Detection of pathological myopia by PAMELA with texture-based features through an SVM approach
10.1260/2040-2295.1.1.1Journal of Healthcare Engineering111-1
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X-ray Diffraction Techniques for Structural Determination of Amorphous Materials
Prevention of corrosion is a vital goal for the Department of Defense when billions of dollars are spent every year. Corrosion resistant materials have applications in all sort of military vehicles, and more importantly in naval vessels and submarines which come in contact with the seawater. An important application of the corrosion resistant material is in the radioactive waste disposable field where the vessels or containers are expected to hold the radioactive toxic materials for thousands of years to surpass the half life of the radiation. It has been known that corrosion resistance can be improved by the used of structurally designed materials in the amorphous state where the atoms are arranged in a non-periodic conditions, even though, some local chemical short range ordering may occur in the amorphous arrangement. On the other hand, the final material can also be elementally tailored to specific application. This work documents in details the characterization effort for the amorphous materials using x-ray diffraction technique as part of the High Performance Corrosion-Resistant Material--Structural Amorphous Metal (HPCRM-SAM) program here at LLNL. The samples are in the form of powders, ribbons and coatings deposited onto parts. Some brief theoretical background is given in order to interpret the results, instrumentation will also be described. The results suggest that the formation of amorphous phase in the metal alloys powders greatly depends on the processing conditions. In most of the powders, especially lot No.06, the result indicates that the materials are amorphous with a very small amount of iron boron alloy. In the ribbon samples, all the samples and of different compositions as well are observed to be amorphous. In most cases, starting from an amorphous powder sample, the coatings are also observed to be amorphous with a small amount of iron oxide, probably due to exposure to air during the thermal spraying process
Fine particulate matter in the tropical environment: monsoonal effects, source apportionment, and health risk assessment
The health implications of PM2:5 in the tropical
region of Southeast Asia (SEA) are significant as PM2:5
can pose serious health concerns. PM2:5 concentration and
sources here are strongly influenced by changes in the monsoon
regime from the south-west quadrant to the north-east
quadrant in the region. In this work, PM2:5 samples were
collected at a semi-urban area using a high-volume air sampler
at different seasons on 24 h basis. Analysis of trace elements
and water-soluble ions was performed using inductively
coupled plasma mass spectroscopy (ICP-MS) and ion
chromatography (IC), respectively. Apportionment analysis
of PM2:5 was carried out using the United States Environmental
Protection Agency (US EPA) positive matrix factorization
(PMF) 5.0 and a mass closure model. We quantitatively
characterized the health risks posed to human populations
through the inhalation of selected heavy metals in
PM2:5. 48% of the samples collected exceeded the World
Health Organization (WHO) 24 h PM2:5 guideline but only
19% of the samples exceeded 24 h US EPA National Ambient
Air Quality Standard (NAAQS). The PM2:5 concentration
was slightly higher during the north-east monsoon compared
to south-west monsoon. The main trace metals identified
were As, Pb, Cd, Ni, Mn, V, and Cr while the main ions
were SO
One-Dimensional Lateral Force Anisotropy at the Atomic Scale in Sliding Single Molecules on a Surface
Using a q+ atomic force microscopy at low temperature, a sexiphenyl molecule is slid across an atomically flat Ag(111) surface along the direction parallel to its molecular axis and sideways to the axis. Despite identical contact area and underlying surface geometry, the lateral force required to move the molecule in the direction parallel to its molecular axis is found to be about half of that required to move it sideways. The origin of the lateral force anisotropy observed here is traced to the one-dimensional shape of the molecule, which is further confirmed by molecular dynamics simulations. We also demonstrate that scanning tunneling microscopy can be used to determine the comparative lateral force qualitatively. The observed one-dimensional lateral force anisotropy may have important implications in atomic scale frictional phenomena on materials surfaces
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Long-Term Corrosion Testing of Thermal Spray Coatings of Amorphous Metals: Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 and Fe48Mo14Cr15Y2C15B6
Amorphous alloys identified as SAM2X5 (Fe{sub 49.7}Cr{sub 17.7}Mn{sub 1.9}Mo{sub 7.4}W{sub 1.6}B{sub 15.2}C{sub 3.8}Si{sub 2.4}) and SAM1651 (Fe{sub 48}Mo{sub 14}Cr{sub 15}Y{sub 2}C{sub 15}B{sub 6}) have been produced as melt-spun ribbons, drop-cast ingots and thermal-spray coatings. Chromium (Cr), molybdenum (Mo) and tungsten (W) additions provided corrosion resistance, while boron (B) enabled glass formation. Earlier electrochemical studies of melt-spun ribbons and ingots of these amorphous alloys demonstrated outstanding passive film stability. More recently thermal-spray coatings of these amorphous alloys have been made and subjected to long-term salt-fog and immersion tests. Good corrosion resistance has been observed during salt-fog testing. Corrosion rates were measured in situ with linear polarization, while simultaneously monitoring the open-circuit corrosion potentials. Reasonably good performance was observed. The sensitivity of these measurements to electrolyte composition and temperature was determined. The high boron content of SAM2X5 also made it an effective neutron absorber, and suitable for criticality control applications
HIV care in Yangon, Myanmar; successes, challenges and implications for policy
Approximately 0.8% of adults aged 18-49 in Myanmar are seropositive for Human Immunodeficiency Virus (HIV). Identifying the demographic, epidemiological and clinical characteristics of people living with HIV (PLHIV) is essential to inform optimal management strategies in this resource-limited country.To create a "snapshot" of the PLHIV seeking anti-retroviral therapy (ART) in Myanmar, data were collected from the registration cards of all patients who had been prescribed ART at two large referral hospitals in Yangon, prior to March 18, 2016.Anti-retroviral therapy had been prescribed to 2643 patients at the two hospitals. The patients' median [interquartile range (IQR)] age was 37 (31-44) years; 1494 (57%) were male. At registration, injecting drug use was reported in 22 (0.8%), male-to-male sexual contact in eleven (0.4%) and female sex work in eleven (0.4%), suggesting that patients under-report these risk behaviours, that health care workers are uncomfortable enquiring about them or that the two hospitals are under-servicing these populations. All three explanations appear likely. Most patients were symptomatic at registration with 2027 (77%) presenting with WHO stage 3 or 4 disease. In the 2442 patients with a CD4+ T cell count recorded at registration, the median (IQR) count was 169 (59-328) cells/mm3. After a median (IQR) duration of 359 (185-540) days of ART, 151 (5.7%) patients had died, 111 (4.2%) patients had been lost to follow-up, while 2381 were alive on ART. Tuberculosis (TB) co-infection was common: 1083 (41%) were already on anti-TB treatment at registration, while a further 41 (1.7%) required anti-TB treatment during follow-up. Only 21 (0.8%) patients were prescribed isoniazid prophylaxis therapy (IPT); one of these was lost to follow-up, but none of the remaining 20 patients died or required anti-TB treatment during a median (IQR) follow-up of 275 (235-293) days.People living with HIV in Yangon, Myanmar are generally presenting late in their disease course, increasing their risk of death, disease and transmitting the virus. A centralised model of ART prescription struggles to deliver care to the key affected populations. TB co-infection is very common in Myanmar, but despite the proven efficacy of IPT, it is frequently not prescribed.Ne Myo Aung, Josh Hanson, Tint Tint Kyi, Zaw Win Htet, David A. Cooper, Mark A. Boyd, Mar Mar Kyi and Htin Aung Sa
FTO Variants Are Associated With Obesity in the Chinese and Malay Populations in Singapore
OBJECTIVE— Association between genetic variants at the FTO locus and obesity has been consistently observed in populations of European ancestry and inconsistently in non-Europeans. The aim of this study was to examine the effects of FTO variants on obesity and type 2 diabetes in Southeast Asian populations
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The Corrosion Resistance of Fe-Based Amorphous Metals: Fe49.7Cr17.7Mn1.9Mo7.4W1.6B15.2C3.8Si2.4 and Other Compositions
Several Fe-based amorphous metals were developed with good corrosion resistance. These materials have been produced as melt-spun ribbons, ingots, and thermal-spray coatings. Cyclic polarization has been conducted in several aggressive environments, at ambient temperature, as well as temperatures approaching the boiling points of the test solutions. The hypothesis that the corrosion resistance of iron-based amorphous metals can be enhanced through application of heuristic principles related to the additions of chromium, molybdenum, tungsten has been tested and found to have merit. Chromium (Cr), molybdenum (Mo) and tungsten (W) provide corrosion resistance; boron (B) enables glass formation; and rare earths such as yttrium (Y) lower critical cooling rate (CCR). The high boron content of this particular amorphous metal makes this amorphous alloy an effective neutron absorber, and suitable for criticality control applications. In general, the corrosion resistance of such iron-based amorphous metals is maintained at operating temperatures up to the glass transition temperature
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