2,682 research outputs found

    Cave and karst development in the Craven Basin, UK

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    The Craven Basin, which was an area of crustal subsidence during much of the Carboniferous, contains carbonate strata that pre-date the deposition of the better known carbonates of the Askrigg Block to the north. Later basin-fill deposits consist mainly of clastic sedimentary rocks. However, interbedded carbonate horizons and Waulsortian mud-mounds are also present. Karst development has taken place locally on the exposed carbonate strata. including establishment of the only example of a sulphurous cave stream currently known in the British Isles. The caves so far examined in the area are described, alongside an account of their geological setting

    A review of physical supply and EROI of fossil fuels in China

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    This paper reviews China’s future fossil fuel supply from the perspectives of physical output and net energy output. Comprehensive analyses of physical output of fossil fuels suggest that China’s total oil production will likely reach its peak, at about 230 Mt/year (or 9.6 EJ/year), in 2018; its total gas production will peak at around 350 Bcm/year (or 13.6 EJ/year) in 2040, while coal production will peak at about 4400 Mt/year (or 91.9 EJ/year) around 2020 or so. In terms of the forecast production of these fuels, there are significant differences among current studies. These differences can be mainly explained by different ultimately recoverable resources assumptions, the nature of the models used, and differences in the historical production data. Due to the future constraints on fossil fuels production, a large gap is projected to grow between domestic supply and demand, which will need to be met by increasing imports. Net energy analyses show that both coal and oil and gas production show a steady declining trend of EROI (energy return on investment) due to the depletion of shallow-buried coal resources and conventional oil and gas resources, which is generally consistent with the approaching peaks of physical production of fossil fuels. The peaks of fossil fuels production, coupled with the decline in EROI ratios, are likely to challenge the sustainable development of Chinese society unless new abundant energy resources with high EROI values can be found

    3D human skin bioprinting: a view from the bio side

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    Based on the 3D printing technologies and the concepts developed in tissue engineering during the last decades, 3D bioprinting is emerging as the most innovative and promising technology for the generation of human tissues and organs. In the case of skin bioprinting, thanks to the research process carried out during the last years, interfollicular skin has been printed with a structural and functional quality that paves the way for clinical and industrial applications. This review analyzes the present achievements and the future improvements that this area must bring about if bioprinted skin is to become widely used. We have made an effort to integrate the technological and the biological/biomedical sides of the subject.We thank the Spanish Fundación Ramón Areces for its continuous support. This work was partially supported by grant DPI2014-61887-EXP from the Spanish Ministerio de Economía y Competitividad

    Spot sputum samples are at least as good as early morning samples for identifying Mycobacterium tuberculosis

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    Background The use of early morning sputum samples (EMS) to diagnose tuberculosis (TB) can result in treatment delay given the need for the patient to return to the clinic with the EMS, increasing the chance of patients being lost during their diagnostic workup. However, there is little evidence to support the superiority of EMS over spot sputum samples. In this new analysis of the REMoxTB study, we compare the diagnostic accuracy of EMS with spot samples for identifying Mycobacterium tuberculosis pre- and post-treatment. Methods Patients who were smear positive at screening were enrolled into the study. Paired sputum samples (one EMS and one spot) were collected at each trial visit pre- and post-treatment. Microscopy and culture on solid LJ and liquid MGIT media were performed on all samples; those missing corresponding paired results were excluded from the analyses. Results Data from 1115 pre- and 2995 post-treatment paired samples from 1931 patients enrolled in the REMoxTB study were analysed. Patients were recruited from South Africa (47%), East Africa (21%), India (20%), Asia (11%), and North America (1%); 70% were male, median age 31 years (IQR 24–41), 139 (7%) co-infected with HIV with a median CD4 cell count of 399 cells/μL (IQR 318–535). Pre-treatment spot samples had a higher yield of positive Ziehl–Neelsen smears (98% vs. 97%, P = 0.02) and LJ cultures (87% vs. 82%, P = 0.006) than EMS, but there was no difference for positivity by MGIT (93% vs. 95%, P = 0.18). Contaminated and false-positive MGIT were found more often with EMS rather than spot samples. Surprisingly, pre-treatment EMS had a higher smear grading and shorter time-to-positivity, by 1 day, than spot samples in MGIT culture (4.5 vs. 5.5 days, P < 0.001). There were no differences in time to positivity in pre-treatment LJ culture, or in post-treatment MGIT or LJ cultures. Comparing EMS and spot samples in those with unfavourable outcomes, there were no differences in smear or culture results, and positive results were not detected earlier in Kaplan–Meier analyses in either EMS or spot samples. Conclusions Our data do not support the hypothesis that EMS samples are superior to spot sputum samples in a clinical trial of patients with smear positive pulmonary TB. Observed small differences in mycobacterial burden are of uncertain significance and EMS samples do not detect post-treatment positives any sooner than spot samples

    Ischemic preconditioning protects against cardiac ischemia reperfusion injury without affecting succinate accumulation or oxidation.

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    Ischemia-reperfusion (IR) injury occurs when blood supply to an organ is disrupted and then restored, and underlies many disorders, notably myocardial infarction and stroke. While reperfusion of ischemic tissue is essential for survival, it also initiates cell death through generation of mitochondrial reactive oxygen species (ROS). Recent work has revealed a novel pathway underlying ROS production at reperfusion in vivo in which the accumulation of succinate during ischemia and its subsequent rapid oxidation at reperfusion drives ROS production at complex I by reverse electron transport (RET). Pharmacologically inhibiting ischemic succinate accumulation, or slowing succinate metabolism at reperfusion, have been shown to be cardioprotective against IR injury. Here, we determined whether ischemic preconditioning (IPC) contributes to cardioprotection by altering kinetics of succinate accumulation and oxidation during IR. Mice were subjected to a 30-minute occlusion of the left anterior descending coronary artery followed by reperfusion, with or without a protective IPC protocol prior to sustained ischemia. We found that IPC had no effect on ischemic succinate accumulation with both control and IPC mice having profound increases in succinate compared to normoxia. Furthermore, after only 1-minute reperfusion succinate was rapidly metabolised returning to near pre-ischemic levels in both groups. We conclude that IPC does not affect ischemic succinate accumulation, or its oxidation at reperfusion

    Parents' experiences of care offered after stillbirth: An international online survey of high and middle-income countries

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    BACKGROUND: Stillbirth, the death of a baby before birth, is associated with significant psychological and social consequences that can be mitigated by respectful and supportive bereavement care. The absence of high-level evidence to support the broad scope of perinatal bereavement practices means that offering a range of options identified as valued by parents has become an important indicator of care quality. This study aimed to describe bereavement care practices offered to parents across different high-income and middle-income countries. METHODS: An online survey of parents of stillborn babies was conducted between December 2014 and February 2015. Frequencies of nine practices were compared between high-income and middle-income countries. Differences in proportions of reported practices and their associated odds ratios were calculated to compare high-income and middle-income countries. RESULTS: Over three thousand parents (3041) with a self-reported stillbirth in the preceding five years from 40 countries responded. Fifteen countries had atleast 40 responses. Significant differences in the prevalence of offering nine bereavement care practices were reported by women in high-income countries (HICs) compared with women in middle-income countries (MICs). All nine practices were reported to occur significantly more frequently by women in HICs, including opportunity to see and hold their baby (OR = 4.8, 95% CI 4.0-5.9). The widespread occurrence of all nine practices was reported only for The Netherlands. CONCLUSIONS: Bereavement care after stillbirth varies between countries. Future research should look at why these differences occur, their impact on parents, and whether differences should be addressed, particularly how to support effective communication, decision-making, and follow-up care
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