6,134 research outputs found

    Nanostructure of cellulose microfibrils in spruce wood

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    The structure of cellulose microfibrils in wood is not known in detail, despite the abundance of cellulose in woody biomass and its importance for biology, energy, and engineering. The structure of the microfibrils of spruce wood cellulose was investigated using a range of spectroscopic methods coupled to small-angle neutron and wide-angle X-ray scattering. The scattering data were consistent with 24-chain microfibrils and favored a ā€œrectangularā€ model with both hydrophobic and hydrophilic surfaces exposed. Disorder in chain packing and hydrogen bonding was shown to increase outwards from the microfibril center. The extent of disorder blurred the distinction between the I alpha and I beta allomorphs. Chains at the surface were distinct in conformation, with high levels of conformational disorder at C-6, less intramolecular hydrogen bonding and more outward-directed hydrogen bonding. Axial disorder could be explained in terms of twisting of the microfibrils, with implications for their biosynthesis

    Genome sequence of Mycobacterium yongonense RT 955-2015 isolate from a patient misdiagnosed with multidrug-resistant tuberculosis: First clinical detection in Tanzania

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    Background: Mycobacterium yongonense is a recently described novel species belonging to Mycobacterium avium complex, which is the most prevalent aetiology of non-tuberculous mycobacteria associated with pulmonary infections, and poses tuberculosis diagnostic challenges in high-burden, resource-constrained settings. Methods: Whole genome shotgun sequencing and comparative microbial genomic analyses were used to characterize the isolate from a patient diagnosed with multidrug-resistant tuberculosis (MDR-TB) after relapse. Results: The genome sequence of the first case of M. yongonense (M. yongonense RT 955-2015) in Tanzania is presented. Sequence analysis revealed that the RT 955-2015 strain had a high similarity to M. yongonense 05-1390(T) (98.74%) and Mycobacterium chimaera DSM 44623(T) (98%). Its 16S rRNA showed similarity to Mycobacterium paraintracellulare KCTC 290849(T) (100%), Mycobacterium intracellulare ATCC 13950(T) (100%), M. chimaera DSM 44623(T) (99.9%), and M. yongonense 05-1390(T) (98%). The strain exhibited a substantially different rpoB sequence to that of M. yongonense 05-1390 (95.16%), but closely related to that of M. chimaera DSM 44623(T) (99.86%), M. intracellulare ATCC 13950(T), (99.53%), and M. paraintracellulare KCTC 290849(T) (99.53%). Conclusions: In light of the OrthoANI algorithm and phylogenetic analysis, it was concluded that the isolate was M. yongonense Type II genotype, which is an indication that the patient was misdiagnosed with TB/MDR-TB and received inappropriate treatment. (C) 2018 The Author(s). Published by Elsevier Ltd on behalf of International Society for Infectious Diseases.

    "After my husband's circumcision, I know that I am safe from diseases": Women's Attitudes and Risk Perceptions Towards Male Circumcision in Iringa, Tanzania.

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    While male circumcision reduces the risk of female-to-male HIV transmission and certain sexually transmitted infections (STIs), there is little evidence that circumcision provides women with direct protection against HIV. This study used qualitative methods to assess women's perceptions of male circumcision in Iringa, Tanzania. Women in this study had strong preferences for circumcised men because of the low risk perception of HIV with circumcised men, social norms favoring circumcised men, and perceived increased sexual desirability of circumcised men. The health benefits of male circumcision were generally overstated; many respondents falsely believed that women are also directly protected against HIV and that the risk of all STIs is greatly reduced or eliminated in circumcised men. Efforts to engage women about the risks and limitations of male circumcision, in addition to the benefits, should be expanded so that women can accurately assess their risk of HIV or STIs during sexual intercourse with circumcised men

    An Intact Kidney Slice Model to Investigate Vasa Recta Properties and Function in situ

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    Background: Medullary blood flow is via vasa recta capillaries, which possess contractile pericytes. In vitro studies using isolated descending vasa recta show that pericytes can constrict/dilate descending vasa recta when vasoactive substances are present. We describe a live kidney slice model in which pericyte-mediated vasa recta constriction/dilation can be visualized in situ. Methods: Confocal microscopy was used to image calcein, propidium iodide and Hoechst labelling in ā€˜liveā€™ kidney slices, to determine tubular and vascular cell viability and morphology. DIC video-imaging of live kidney slices was employed to investigate pericyte-mediated real-time changes in vasa recta diameter. Results: Pericytes were identified on vasa recta and their morphology and density were characterized in the medulla. Pericyte-mediated changes in vasa recta diameter (10ā€“30%) were evoked in response to bath application of vasoactive agents (norepinephrine, endothelin-1, angiotensin-II and prostaglandin E2) or by manipulating endogenous vasoactive signalling pathways (using tyramine, L-NAME, a cyclo-oxygenase (COX-1) inhibitor indomethacin, and ATP release). Conclusions: The live kidney slice model is a valid complementary technique for investigating vasa recta function in situ and the role of pericytes as regulators of vasa recta diameter. This technique may also be useful in exploring the role of tubulovascular crosstalk in regulation of medullary blood flow

    Testing in the incremental design and development of complex products

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    Testing is an important aspect of design and development which consumes significant time and resource in many companies. However, it has received less research attention than many other activities in product development, and especially, very few publications report empirical studies of engineering testing. Such studies are needed to establish the importance of testing and inform the development of pragmatic support methods. This paper combines insights from literature study with findings from three empirical studies of testing. The case studies concern incrementally developed complex products in the automotive domain. A description of testing practice as observed in these studies is provided, confirming that testing activities are used for multiple purposes depending on the context, and are intertwined with design from start to finish of the development process, not done after it as many models depict. Descriptive process models are developed to indicate some of the key insights, and opportunities for further research are suggested

    Targeted hepatitis C antibody testing interventions: a systematic review and meta-analysis

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    Testing for hepatitis C virus (HCV) infection may reduce the risk of liver-related morbidity, by facilitating earlier access to treatment and care. This review investigated the effectiveness of targeted testing interventions on HCV case detection, treatment uptake, and prevention of liver-related morbidity. A literature search identified studies published up to 2013 that compared a targeted HCV testing intervention (targeting individuals or groups at increased risk of HCV) with no targeted intervention, and results were synthesised using meta-analysis. Exposure to a targeted testing intervention, compared to no targeted intervention, was associated with increased cases detected [number of studies (n)Ā =Ā 14; pooled relative risk (RR) 1.7, 95Ā % CI 1.3, 2.2] and patients commencing therapy (nĀ =Ā 4; RR 3.3, 95Ā % CI 1.1, 10.0). Practitioner-based interventions increased test uptake and cases detected (nĀ =Ā 12; RR 3.5, 95Ā % CI 2.5, 4.8; and nĀ =Ā 10; RR 2.2, 95Ā % CI 1.4, 3.5, respectively), whereas media/information-based interventions were less effective (nĀ =Ā 4; RR 1.5, 95Ā % CI 0.7, 3.0; and nĀ =Ā 4; RR 1.3, 95Ā % CI 1.0, 1.6, respectively). This meta-analysis provides for the first time a quantitative assessment of targeted HCV testing interventions, demonstrating that these strategies were effective in diagnosing cases and increasing treatment uptake. Strategies involving practitioner-based interventions yielded the most favourable outcomes. It is recommended that testing should be targeted at and offered to individuals who are part of a population with high HCV prevalence, or who have a history of HCV risk behaviour

    Trend and Outcome of Korean Patients Receiving Overseas Solid Organ Transplantation between 1999 and 2005

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    The disparity between patients awaiting transplantation and available organs forced many patients to go overseas to receive a transplant. Few data concerning overseas transplantation in Korea are available and the Korea Society for Transplantation conducted a survey to evaluate the trend and outcome of overseas transplantation. The survey, conducted on June 2006, included 25 hospitals nationwide that followed up patients after receiving kidney transplant (KT) or liver transplant (LT) overseas. The number of KT increased from 6 in 2001 to 206 in 2005 and for LT from 1 to 261. The information about overseas transplant came mostly from other patients (57%). The mean cost for KT was 21,000andforLT21,000 and for LT 47,000. Patients were admitted for 18.5 days for KT and 43.4 days for LT. Graft and patient survival was 96.8% and 96.5% for KT (median follow up 23.1 months). Complication occurred in 42.5% including surgical complication (5.3%), acute rejection (9.7%) and infection (21.5%). Patient survival for LT was 91.8% (median follow up 21.2 months). Complication occurred in 44.7% including 19.4% biliary complication. Overseas KT and LT increased rapidly from 2001 to 2005. Survival of patients and grafts was comparable to domestic organ transplantation, but had a high complication rate
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