213 research outputs found

    1,5-Anhydro-2-de­oxy-1,2-C-dichloro­methyl­ene-3,4,6-tri-O-(4-meth­oxy­benz­yl)-d-glycero-d-gulo-hexitol

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    The pyranosyl ring in the title compound, C31H34Cl2O7, adopts a twist-boat conformation. The 4-meth­oxy­benzyl groups are located in equatorial positions with the meth­oxy groups nearly coplanar with their respective rings [dihedral angles of 0.2 (3) and 9.4 (2)°]. The aromatic rings adopt orientations enabling them to participate in C—H⋯π inter­actions with neighboring meth­oxy groups. The crystal structure is additionally stabilized by weak C—H⋯O inter­actions

    Kinetic versus Magnetic Chaos in Toroidal Plasmas: A systematic quantitative comparison

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    Magnetic field line chaos occurs under the presence of non-axisymmetric perturbations of an axisymmetric equilibrium and is manifested by the destruction of smooth flux surfaces formed by the field lines. These perturbations also render the particle motion, as described by the guiding center dynamics, non-integrable and, therefore, chaotic. However, the chaoticities of the magnetic field lines and the particle orbits significantly differ both in strength and radial location in a toroidal configuration, except for the case of very low-energy particles whose orbits closely follow the magnetic field lines. The chaoticity of more energetic particles, undergoing large drifts with respect to the magnetic field lines, crucially determines the confinement properties of a toroidal device but cannot be inferred from that of the underlying magnetic field. In this work, we implement the Smaller ALignment Index (SALI) method for detecting and quantifying chaos, allowing for a systematic comparison between magnetic and kinetic chaos. The efficient quantification of chaos enables the assignment of a value characterizing the chaoticity of each orbit in the space of the three constants of the motion, namely energy, magnetic moment and toroidal momentum. The respective diagrams provide a unique overview of the different effects of a specific set of perturbations on the entire range of trapped and passing particles, as well as the radial location of the chaotic regions, offering a valuable tool for the study of particle energy and momentum transport and confinement properties of a toroidal fusion device.Comment: 27 pages, 7 figure

    Effectiveness of a simple lymphoedema treatment regimen in podoconiosis management in southern Ethiopia: one year follow-up

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    Background: Podoconiosis is a non-filarial elephantiasis caused by long-term barefoot exposure to volcanic soils in endemic areas. Irritant silicate particles penetrate the skin, causing a progressive, debilitating lymphoedema of the lower leg, often starting in the second decade of life. A simple patient-led treatment approach appropriate for resource poor settings has been developed, comprising (1) education on aetiology and prevention of podoconiosis, (2) foot hygiene (daily washing with soap, water and an antiseptic), (3) the regular use of emollient, (4) elevation of the limb at night, and (5) emphasis on the consistent use of shoes and socks. Methodology/Principal Findings: We did a 12-month, non-comparative, longitudinal evaluation of 33 patients newly presenting to one clinic site of a non-government organization (the Mossy Foot Treatment & Prevention Association, MFTPA) in southern Ethiopia. Outcome measures used for the monitoring of disease progress were (1) the clinical staging system for podoconiosis, and (2) the Amharic Dermatology Life Quality Index (DLQI), both of which have been recently validated for use in this setting. Digital photographs were also taken at each visit. Twenty-seven patients completed follow up. Characteristics of patients completing follow-up were not significantly different to those not. Mean clinical stage and lower leg circumference decreased significantly (mean difference -0.67 (95% CI -0.38 to -0.96) and -2.00 (95% CI -1.26 to -2.74), respectively, p<0.001 for both changes). Mean DLQI diminished from 21 (out of a maximum of 30) to 6 (p<0.001). There was a non-significant change in proportion of patients with mossy lesions (p = 0.375). Conclusions/Significance: This simple, resource-appropriate regimen has a considerable impact both on clinical progression and self-reported quality of life of affected individuals. The regimen appears ideal for scaling up to other endemic regions in Ethiopia and internationally. We recommend that further research in the area include analysis of cost-effectiveness of the regimen

    High prevalence of vaccine-preventable anal human papillomavirus infections is associated with HIV infection among gay, bisexual, and men who have sex with men in Nairobi, Kenya

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    Background: Human papillomavirus (HPV) infection is associated with anal cancers and is more prevalent in gay, bisexual, and men who have sex with men (gbMSM), partly due to their vulnerability to HIV infection. Baseline HPV genotype distributions and risk factors can inform the design of next-generation HPV vaccines to prevent anal cancer. Methods: A cross-sectional study was conducted among gbMSM receiving care at a HIV/STI clinic in Nairobi, Kenya. Anal swabs were genotyped using a Luminex microsphere array. Multiple logistic regression methods were used to identify risk factors for four HPV outcomes (any HPV, any HR-HPV, and 4- and 9-valent vaccine-preventable HPVs). Results: Among 115 gbMSM, 51 (44.3%) were HIV-infected. Overall HPV prevalence was 51.3%; 84.3% among gbMSM living with HIV and 24.6% among gbMSM without HIV (p \u3c 0.001). One-third (32.2%) had HR-HPV and the most prevalent vaccine-preventable HR-HPV genotypes were 16, 35, 45, and 58. HPV-18 was uncommon (n = 2). The 9-valent Gardasil vaccine would have prevented 61.0% of HPV types observed in this population. In multivariate analyses, HIV status was the only significant risk factor for any HPV (adjusted odds ratio [aOR]:23.0, 95% confidence interval [95% CI]: 7.3–86.0, p \u3c 0.001) and for HR-HPV (aOR: 8.9, 95% CI: 2.8–36.0, p \u3c 0.001). Similar findings were obtained for vaccine-preventable HPVs. Being married to a woman significantly increased the odds of having HR-HPV infections (aOR: 8.1, 95% CI: 1.6–52.0, p = 0.016). Conclusions: GbMSM living with HIV in Kenya are at higher risk of anal HPV infections including genotypes that are preventable with available vaccines. Our findings support the need for a targeted HPV vaccination campaign in this population

    Quantum Phase Transition in a Resonant Level Coupled to Interacting Leads

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    An interacting one-dimensional electron system, the Luttinger liquid, is distinct from the "conventional" Fermi liquids formed by interacting electrons in two and three dimensions. Some of its most spectacular properties are revealed in the process of electron tunneling: as a function of the applied bias or temperature the tunneling current demonstrates a non-trivial power-law suppression. Here, we create a system which emulates tunneling in a Luttinger liquid, by controlling the interaction of the tunneling electron with its environment. We further replace a single tunneling barrier with a double-barrier resonant level structure and investigate resonant tunneling between Luttinger liquids. For the first time, we observe perfect transparency of the resonant level embedded in the interacting environment, while the width of the resonance tends to zero. We argue that this unique behavior results from many-body physics of interacting electrons and signals the presence of a quantum phase transition (QPT). In our samples many parameters, including the interaction strength, can be precisely controlled; thus, we have created an attractive model system for studying quantum critical phenomena in general. Our work therefore has broadly reaching implications for understanding QPTs in more complex systems, such as cold atoms and strongly correlated bulk materials.Comment: 11 pages total (main text + supplementary

    Opportunities and Challenges of Harnessing Biomass Wastes for Decentralized Heat and Energy Generation and Climate Mitigation via Fluidized-bed Gasification Pathway

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    Biomass wastes offer immense potential as a renewable energy source, holding the promise to replace fossil fuels for heat and energy generation, in particular for decentralized power production. Furthermore, the utilization of biomass promotes circular economy by enabling the conversion of local resources into useful products and energy. However, the conversion of biomass into end-use products and heat/energy is a complex process with multiple pathways, such as fluidized bed gasification, a well-established and efficient method for converting coal and biomass into heat. Despite its merits, this process is currently limited to industrial applications and encounters certain limitations and obstacles. Notably, the low energy density of biomass wastes and downstream pipe contamination from tar and polycyclic aromatic hydrocarbon (PAH) growth poses significant technological challenges. Nonetheless, a roadmap has been developed to guide the widespread adoption of fluidized bed gasification of biomass for decentralized power generation and climate mitigation. This book chapter delves into the opportunities and challenges of fluidized bed gasification as a viable option for decentralized power generation and climate mitigation through biomass waste conversion. The significance of well-crafted policies supporting renewable energy sources and optimizing fluidized bed gasifiers to achieve desirable end products are also emphasized

    Podoconiosis treatment in northern Ethiopia (GoLBet): study protocol for a randomised controlled trial

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    BACKGROUND Podoconiosis is one of the forgotten types of leg swelling (elephantiasis) in the tropics. Unlike the other, better-known types of leg swelling, podoconiosis is not caused by any parasite, virus or bacterium, but by an abnormal reaction to minerals found in the clay soils of some tropical highland areas. Non-governmental Organizations (NGOs) have been responsible for the development of simple treatment methods without systematic evaluation of its effectiveness. It is essential that a large scale, fully controlled, pragmatic trial of the intervention is conducted. We aim to test the hypothesis that community-based treatment of podoconiosis lymphoedema reduces the frequency of acute dermatolymphangioadenitis episodes ('acute attacks') and improves other clinical, social and economic outcomes. METHODS/DESIGN This is a pragmatic, individually randomised controlled trial. We plan to randomly allocate 680 podoconiosis patients from the East Gojjam Zone in northern Ethiopia to one of two groups: 'Standard Treatment' or 'Delayed Treatment'. Those randomised to standard treatment will receive the hygiene and foot-care intervention from May 2015 for one year, whereas those in the control arm will be followed through 2015 and be offered the intervention in 2016. The trial will be preceded by an economic context survey and a Rapid Ethical Assessment to identify optimal methods of conveying information about the trial and the approaches to obtaining informed consent preferred by the community. The primary outcome will be measured by recording patient recall and using a simple, patient-held diary that will be developed to record episodes of acute attacks. Adherence to treatment, clinical stage of disease, quality of life, disability and stigma will be considered secondary outcome measures. Other outcomes will include adverse events and economic productivity. Assessments will be made at baseline and at 3, 6, 9 and 12 months thereafter. DISCUSSION The evidence is highly likely to inform implementation of the new master plan for integrated control of Neglected Tropical Diseases (NTDs), in which podoconiosis is identified as one of eight NTDs prioritised for control. Potentially, an estimated 3 million patients in Ethiopia will therefore benefit from the results of this trial. TRIAL REGISTRATION International Standard Randomised Controlled Trial Number. REGISTRATION NUMBER ISRCTN67805210 . Date of registration: 24 January 2013

    Social-ecological assessment of Lake Manyara basin, Tanzania: A mixed method approach.

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    This research article published by Elsevier Ltd., 2020The social-ecological system of the Lake Manyara basin (Northern Tanzania), a UNESCO Biosphere reserve (BR) suffers from social-economic and environmental problems due to decreasing water levels, erosion and land and water use conflicts. We propose an integrated assessment of the social-ecological interactions of the area to support future sustainable management. Within the Drivers-Pressures-State-Impact-Response (DPSIR) framework an integrated literature review and several methods of knowledge collection were combined to identify future management priorities and challenges. During focus groups with farmers and pastoralists, stakeholders confirmed the role played by land use changes as driver and pressure in the landscape, e.g. through increased erosion rates and siltation of the lake. Moreover, economic and social issues were identified as prominent factors being influenced by, or influencing these processes. These statements match the scientific literature. During participatory mapping exercises different spatial and resource allocation perceptions appeared amongst pastoralists and farmers. The multidisciplinary approach proved to be useful to acquire an integrated and comprehensive understanding of the state, challenges and opportunities of Lake Manyara BR, to feed into a decision support system in service of an integrated management plan. Our assessment suggests that improved water governance in a multi-actor approach (with a focus on distribution of benefits, rights, and a specific role of the water authorities) should be a priority for future integrated management strategies. Also, awareness raising amongst decision makers, scientists and local communities is needed to demonstrate the advantages of an integrated approach. And finally, visible and fair mechanisms to share conservation revenues should be designed in a way that local benefits can be obtained together with incentive mechanisms for co-management and conservation

    Global, regional, and national burden of tuberculosis, 1990–2016: results from the Global Burden of Diseases, Injuries, and Risk Factors 2016 Study

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    Background Although a preventable and treatable disease, tuberculosis causes more than a million deaths each year. As countries work towards achieving the Sustainable Development Goal (SDG) target to end the tuberculosis epidemic by 2030, robust assessments of the levels and trends of the burden of tuberculosis are crucial to inform policy and programme decision making. We assessed the levels and trends in the fatal and non-fatal burden of tuberculosis by drug resistance and HIV status for 195 countries and territories from 1990 to 2016. Methods We analysed 15 943 site-years of vital registration data, 1710 site-years of verbal autopsy data, 764 site-years of sample-based vital registration data, and 361 site-years of mortality surveillance data to estimate mortality due to tuberculosis using the Cause of Death Ensemble model. We analysed all available data sources, including annual case notifications, prevalence surveys, population-based tuberculin surveys, and estimated tuberculosis cause-specific mortality to generate internally consistent estimates of incidence, prevalence, and mortality using DisMod-MR 2.1, a Bayesian meta-regression tool. We assessed how the burden of tuberculosis differed from the burden predicted by the Socio-demographic Index (SDI), a composite indicator of income per capita, average years of schooling, and total fertility rate. Findings Globally in 2016, among HIV-negative individuals, the number of incident cases of tuberculosis was 9·02 million (95% uncertainty interval [UI] 8·05–10·16) and the number of tuberculosis deaths was 1·21 million (1·16–1·27). Among HIV-positive individuals, the number of incident cases was 1·40 million (1·01–1·89) and the number of tuberculosis deaths was 0·24 million (0·16–0·31). Globally, among HIV-negative individuals the age-standardised incidence of tuberculosis decreased annually at a slower rate (–1·3% [–1·5 to −1·2]) than mortality did (–4·5% [–5·0 to −4·1]) from 2006 to 2016. Among HIV-positive individuals during the same period, the rate of change in annualised age-standardised incidence was −4·0% (–4·5 to −3·7) and mortality was −8·9% (–9·5 to −8·4). Several regions had higher rates of age-standardised incidence and mortality than expected on the basis of their SDI levels in 2016. For drug-susceptible tuberculosis, the highest observed-to-expected ratios were in southern sub-Saharan Africa (13·7 for incidence and 14·9 for mortality), and the lowest ratios were in high-income North America (0·4 for incidence) and Oceania (0·3 for mortality). For multidrug-resistant tuberculosis, eastern Europe had the highest observed-to-expected ratios (67·3 for incidence and 73·0 for mortality), and high-income North America had the lowest ratios (0·4 for incidence and 0·5 for mortality). Interpretation If current trends in tuberculosis incidence continue, few countries are likely to meet the SDG target to end the tuberculosis epidemic by 2030. Progress needs to be accelerated by improving the quality of and access to tuberculosis diagnosis and care, by developing new tools, scaling up interventions to prevent risk factors for tuberculosis, and integrating control programmes for tuberculosis and HIV
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