488 research outputs found

    Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

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    Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties

    Surgical Management of Inguinal Hernias at Bugando Medical Centre in Northwestern Tanzania: Our Experiences in a Resource-Limited Setting.

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    Inguinal hernia repair remains the commonest operation performed by general surgeons all over the world. There is paucity of published data on surgical management of inguinal hernias in our environment. This study is intended to describe our own experiences in the surgical management of inguinal hernias and compare our results with that reported in literature. A descriptive prospective study was conducted at Bugando Medical Centre in northwestern Tanzania. Ethical approval to conduct the study was obtained from relevant authorities before the commencement of the study. Statistical data analysis was done using SPSS software version 17.0. A total of 452 patients with inguinal hernias were enrolled in the study. The median age of patients was 36 years (range 3 months to 78 years). Males outnumbered females by a ratio of 36.7:1. This gender deference was statistically significant (P=0.003). Most patients (44.7%) presented late (more than five years of onset of hernia). Inguinoscrotal hernia (66.8%) was the commonest presentation. At presentation, 208 (46.0%) patients had reducible hernia, 110 (24.3%) had irreducible hernia, 84 (18.6%) and 50(11.1%) patients had obstructed and strangulated hernias respectively. The majority of patients (53.1%) had right sided inguinal hernia with a right-to-left ratio of 2.1: 1. Ninety-two (20.4%) patients had bilateral inguinal hernias. 296 (65.5%) patients had indirect hernia, 102 (22.6%) had direct hernia and 54 (11.9%) had both indirect and direct types (pantaloon hernia). All patients in this study underwent open herniorrhaphy. The majority of patients (61.5%) underwent elective herniorrhaphy under spinal anaesthesia (69.2%). Local anaesthesia was used in only 1.1% of cases. Bowel resection was required in 15.9% of patients. Modified Bassini's repair (79.9%) was the most common technique of posterior wall repair of the inguinal canal. Lichtenstein mesh repair was used in only one (0.2%) patient. Complication rate was 12.4% and it was significantly higher in emergency herniorrhaphy than in elective herniorrhaphy (P=0.002). The median length of hospital stay was 8 days and it was significantly longer in patients with advanced age, delayed admission, concomitant medical illness, high ASA class, the need for bowel resection and in those with surgical repair performed under general anesthesia (P<0.001). Mortality rate was 9.7%. Longer duration of symptoms, late hospitalization, coexisting disease, high ASA class, delayed operation, the need for bowel resection and presence of complications were found to be predictors of mortality (P<0.001). Inguinal hernias continue to be a source of morbidity and mortality in our centre. Early presentation and elective repair of inguinal hernias is pivotal in order to eliminate the morbidity and mortality associated with this very common problem

    Proton-Binding Sites of Acid-Sensing Ion Channel 1

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    Acid-sensing ion channels (ASICs) are proton-gated cation channels that exist throughout the mammalian central and peripheral nervous systems. ASIC1 is the most abundant of all the ASICs and is likely to modulate synaptic transmission. Identifying the proton-binding sites of ASCI1 is required to elucidate its pH-sensing mechanism. By using the crystal structure of ASIC1, the protonation states of each titratable site of ASIC1 were calculated by solving the Poisson-Boltzmann equation under conditions wherein the protonation states of all these sites are simultaneously in equilibrium. Four acidic-acidic residue pairs—Asp238-Asp350, Glu220-Asp408, Glu239-Asp346, and Glu80-Glu417—were found to be highly protonated. In particular, the Glu80-Glu417 pair in the inner pore was completely protonated and possessed 2 H+, implying its possible importance as a proton-binding site. The pKa of Glu239, which forms a pair with a possible pH-sensing site Asp346, differs among each homo-trimer subunit due to the different H-bond pattern of Thr237 in the different protein conformations of the subunits. His74 possessed a pKa of ≈6–7. Conservation of His74 in the proton-sensitive ASIC3 that lacks a residue corresponding to Asp346 may suggest its possible pH-sensing role in proton-sensitive ASICs

    Captive reptile mortality rates in the home and implications for the wildlife trade

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    The trade in wildlife and keeping of exotic pets is subject to varying levels of national and international regulation and is a topic often attracting controversy. Reptiles are popular exotic pets and comprise a substantial component of the live animal trade. High mortality of traded animals raises welfare concerns, and also has implications for conservation if collection from the wild is required to meet demand. Mortality of reptiles can occur at any stage of the trade chain from collector to consumer. However, there is limited information on mortality rates of reptiles across trade chains, particularly amongst final consumers in the home. We investigated mortality rates of reptiles amongst consumers using a specialised technique for asking sensitive questions, additive Randomised Response Technique (aRRT), as well as direct questioning (DQ). Overall, 3.6% of snakes, chelonians and lizards died within one year of acquisition. Boas and pythons had the lowest reported mortality rates of 1.9% and chameleons had the highest at 28.2%. More than 97% of snakes, 87% of lizards and 69% of chelonians acquired by respondents over five years were reported to be captive bred and results suggest that mortality rates may be lowest for captive bred individuals. Estimates of mortality from aRRT and DQ did not differ significantly which is in line with our findings that respondents did not find questions about reptile mortality to be sensitive. This research suggests that captive reptile mortality in the home is rather low, and identifies those taxa where further effort could be made to reduce mortality rate

    The contribution of Swiss scientists to the assessment of energy metabolism

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    Although Switzerland is considered a small country, it has its share in discoveries, inventions and developments for the assessment of energy metabolism. This includes seminal contributions to respiratory and metabolic physiology and to devices for measuring energy expenditure by direct and indirect calorimetry in vivo in humans and small animals (as well as in vitro in organs/tissues), for the purpose of evaluating the basic nutritional requirements. A strong momentum came during World War II when it was necessary to evaluate the energy requirements of soldiers protecting the country by assessing their energy expenditure, as well as to determine the nutritional needs of the Swiss civil population in time of war when food rationing was necessary to ensure national neutrality and independence. A further impetus came in the 1970s at the start of the obesity epidemics, toward a better understanding of the metabolic basis of obesity, ranging from the development of whole-body concepts to molecular mechanisms. In a trip down memory lane, this review focuses on some of the earlier leading Swiss scientists who have contributed to a better understanding of the field

    Physics, Astrophysics and Cosmology with Gravitational Waves

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    Gravitational wave detectors are already operating at interesting sensitivity levels, and they have an upgrade path that should result in secure detections by 2014. We review the physics of gravitational waves, how they interact with detectors (bars and interferometers), and how these detectors operate. We study the most likely sources of gravitational waves and review the data analysis methods that are used to extract their signals from detector noise. Then we consider the consequences of gravitational wave detections and observations for physics, astrophysics, and cosmology.Comment: 137 pages, 16 figures, Published version <http://www.livingreviews.org/lrr-2009-2

    A systematic review and meta-synthesis of the impact of low back pain on people's lives

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    Copyright @ 2014 Froud et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited.Background - Low back pain (LBP) is a common and costly problem that many interpret within a biopsychosocial model. There is renewed concern that core-sets of outcome measures do not capture what is important. To inform debate about the coverage of back pain outcome measure core-sets, and to suggest areas worthy of exploration within healthcare consultations, we have synthesised the qualitative literature on the impact of low back pain on people’s lives. Methods - Two reviewers searched CINAHL, Embase, PsycINFO, PEDro, and Medline, identifying qualitative studies of people’s experiences of non-specific LBP. Abstracted data were thematic coded and synthesised using a meta-ethnographic, and a meta-narrative approach. Results - We included 49 papers describing 42 studies. Patients are concerned with engagement in meaningful activities; but they also want to be believed and have their experiences and identity, as someone ‘doing battle’ with pain, validated. Patients seek diagnosis, treatment, and cure, but also reassurance of the absence of pathology. Some struggle to meet social expectations and obligations. When these are achieved, the credibility of their pain/disability claims can be jeopardised. Others withdraw, fearful of disapproval, or unable or unwilling to accommodate social demands. Patients generally seek to regain their pre-pain levels of health, and physical and emotional stability. After time, this can be perceived to become unrealistic and some adjust their expectations accordingly. Conclusions - The social component of the biopsychosocial model is not well represented in current core-sets of outcome measures. Clinicians should appreciate that the broader impact of low back pain includes social factors; this may be crucial to improving patients’ experiences of health care. Researchers should consider social factors to help develop a portfolio of more relevant outcome measures.Arthritis Research U

    XLMR in MRX families 29, 32, 33 and 38 results from the dup24 mutation in the ARX (Aristaless related homeobox) gene

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    BACKGROUND: X-linked mental retardation (XLMR) is the leading cause of mental retardation in males. Mutations in the ARX gene in Xp22.1 have been found in numerous families with both nonsyndromic and syndromic XLMR. The most frequent mutation in this gene is a 24 bp duplication in exon 2. Based on this fact, a panel of XLMR families linked to Xp22 was tested for this particular ARX mutation. METHODS: Genomic DNA from XLMR families linked to Xp22.1 was amplified for exon 2 in ARX using a Cy5 labeled primer pair. The resulting amplicons were sized using the ALFexpress automated sequencer. RESULTS: A panel of 11 families with X-linked mental retardation was screened for the ARX 24dup mutation. Four nonsyndromic XLMR families – MRX29, MRX32, MRX33 and MRX38 – were found to have this particular gene mutation. CONCLUSION: We have identified 4 additional XLMR families with the ARX dup24 mutation from a panel of 11 XLMR families linked to Xp22.1. This finding makes the ARX dup24 mutation the most common mutation in nonsyndromic XLMR families linked to Xp22.1. As this mutation can be readily tested for using an automated sequencer, screening should be considered for any male with nonsyndromic MR of unknown etiology

    Comparative genomic hybridization detects many recurrent imbalances in central nervous system primitive neuroectodermal tumours in children

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    A series of 23 children with primitive neuroectodermal tumours (PNET) were analysed with comparative genomic hybridization (CGH). Multiple chromosomal imbalances have been detected in 20 patients. The most frequently involved chromosome was chromosome 17, with a gain of 17q (11 cases) and loss of 17p (eight cases). Further recurrent copy number changes were detected. Extra copies of chromosome 7 were present in nine patients and gains of 1q were detected in six patients. A moderate genomic amplification was detected in one patient, involving two sites on 3p and the whole 12p. Losses were more frequent, and especially involved the chromosomes 11 (nine cases), 10q (eight cases), 8 (six cases), X (six patients) and 3 (five cases), and part of chromosome 9 (five cases). These recurrent chromosomal changes may highlight locations of novel genes with an important role in the development and/or progression of PNET. © 1999 Cancer Research Campaig
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