3,836 research outputs found

    Characterization of a Si(Li) Compton polarimeter for the hard x-ray regime, using synchrotron radiation.

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    BACKGROUND: Buruli ulcer (BU), caused by Mycobacterium ulcerans (M. ulcerans), is a necrotizing skin disease found in more than 30 countries worldwide. BU incidence is highest in West Africa; however, cases have substantially increased in coastal regions of southern Australia over the past 30 years. Although the mode of transmission remains uncertain, the spatial pattern of BU emergence in recent years seems to suggest that there is an environmental niche for M. ulcerans and BU prevalence. METHODOLOGY/PRINCIPAL FINDINGS: Network analysis was applied to BU cases in Victoria, Australia, from 1981-2008. Results revealed a non-random spatio-temporal pattern at the regional scale as well as a stable and efficient BU disease network, indicating that deterministic factors influence the occurrence of this disease. Monthly BU incidence reported by locality was analyzed with landscape and climate data using a multilevel Poisson regression approach. The results suggest the highest BU risk areas occur at low elevations with forested land cover, similar to previous studies of BU risk in West Africa. Additionally, climate conditions as far as 1.5 years in advance appear to impact disease incidence. Warmer and wetter conditions 18-19 months prior to case emergence, followed by a dry period approximately 5 months prior to case emergence seem to favor the occurrence of BU. CONCLUSIONS/SIGNIFICANCE: The BU network structure in Victoria, Australia, suggests external environmental factors favor M. ulcerans transmission and, therefore, BU incidence. A unique combination of environmental conditions, including land cover type, temperature and a wet-dry sequence, may produce habitat characteristics that support M. ulcerans transmission and BU prevalence. These findings imply that future BU research efforts on transmission mechanisms should focus on potential vectors/reservoirs found in those environmental niches. Further, this study is the first to quantitatively estimate environmental lag times associated with BU outbreaks, providing insights for future transmission investigations

    Adults with corrected oesophageal atresia: is oesophageal function associated with complaints and/or quality of life?

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    The aim of this study was to evaluate oesophageal function after correction of oesophageal atresia in adults, and to investigate the association between complaints, oesophageal function and quality of life (QoL). Twenty-five adults were included who participated in previous follow-up studies, during which complaints of dysphagia and gastro-oesophageal reflux (GOR), results of upper gastrointestinal endoscopy, oesophageal biopsies and QoL had been collected. Manometry was performed in 20 patients, 24 h pH-measurements were performed in 21 patients. pH-values (sample time 5 s) were calculated using criteria of Johnson and DeMeester. Associations were tested with ANOVA and χ2-tests. Ten patients (48%) reported complaints of dysphagia, seven (33%) of GOR. The amplitude of oesophageal contractions was low (<15 mmHg) in four patients (20%). pH-measurements showed pathological reflux in three patients (14%). Patients reporting dysphagia more often had disturbed motility (P = 0.011), and lower scores on the domains “general health perceptions” (SF-36) (P = 0.026), “standardised physical component” (SF-36) (P = 0.013), and “physical well-being” (GIQLI) (0.047). No other associations were found. This study shows a high percentage of oesophageal motility disturbances and a moderate percentage of GOR after correction of oesophageal atresia. Patients reporting dysphagia, whom more often had disturbed motility, seemed to be affected by these symptoms in their QoL

    Phylogeny of Prokaryotes and Chloroplasts Revealed by a Simple Composition Approach on All Protein Sequences from Complete Genomes Without Sequence Alignment

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    The complete genomes of living organisms have provided much information on their phylogenetic relationships. Similarly, the complete genomes of chloroplasts have helped to resolve the evolution of this organelle in photosynthetic eukaryotes. In this paper we propose an alternative method of phylogenetic analysis using compositional statistics for all protein sequences from complete genomes. This new method is conceptually simpler than and computationally as fast as the one proposed by Qi et al. (2004b) and Chu et al. (2004). The same data sets used in Qi et al. (2004b) and Chu et al. (2004) are analyzed using the new method. Our distance-based phylogenic tree of the 109 prokaryotes and eukaryotes agrees with the biologists tree of life based on 16S rRNA comparison in a predominant majority of basic branching and most lower taxa. Our phylogenetic analysis also shows that the chloroplast genomes are separated to two major clades corresponding to chlorophytes s.l. and rhodophytes s.l. The interrelationships among the chloroplasts are largely in agreement with the current understanding on chloroplast evolution

    The effect of spinach leaf powder (spinacia oleracea) on the quality of dried noodle

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    This study has utilized the incorporation of different concentrations of spinach powder into wheat flour to produce the best formulation of dried spinach noodle based on sensory and physicochemical tests comprising of colour and texture profile analyses. F2 consists of 4g of spinach powder and was selected as the best formulation. F2 shows a better result than control in terms of significantly higher moisture (8.21 ± 0.01%), ash (3.33 ± 0.01%), crude protein (14.22 ± 0.01%), crude fiber content (8.69 ± 0.06%) and lower crude fat (5.46 ± 0.05%) and carbohydrate content (60.09 ± 0.13%); and also contains a significantly higher total chlorophyll content (24.68 ± 0.01mg/L). The F2 sample also has a lower cooking time (5.33 ± 0.06 minutes), cooking loss (7.43 ± 0.13%), and swelling index (1.85 ± 0.03 ml/g), but a higher cooking weight (246.52 ± 0.01g) and water absorption (161.26 ± 0.10%). The storage quality of the best formulation was conducted for 8 weeks and results were recorded every week. Based on the storage stability result of water activity, moisture content, and microbiological count, all of the values are within the acceptable range and are still safe for consumption. No significant difference was observed for all texture parameters of the F2 noodle upon storage. However, the colour of F2 noodle increase in lightness, greenness, and decrease in yellowness. Overall, the incorporation of spinach powder into noodles can increase the nutrient content and maintain its eating quality

    Robust Framework for PET Image Reconstruction Incorporating System and Measurement Uncertainties

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    In Positron Emission Tomography (PET), an optimal estimate of the radioactivity concentration is obtained from the measured emission data under certain criteria. So far, all the well-known statistical reconstruction algorithms require exactly known system probability matrix a priori, and the quality of such system model largely determines the quality of the reconstructed images. In this paper, we propose an algorithm for PET image reconstruction for the real world case where the PET system model is subject to uncertainties. The method counts PET reconstruction as a regularization problem and the image estimation is achieved by means of an uncertainty weighted least squares framework. The performance of our work is evaluated with the Shepp-Logan simulated and real phantom data, which demonstrates significant improvements in image quality over the least squares reconstruction efforts

    Cross-Linking Amine-Rich Compounds into High Performing Selective CO2 Absorbents

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    Amine-based absorbents play a central role in CO2 sequestration and utilization. Amines react selectively with CO2, but a drawback is the unproductive weight of solvent or support in the absorbent. Efforts have focused on metal organic frameworks (MOFs) reaching extremely high CO2 capacity, but limited selectivity to N2 and CH4, and decreased uptake at higher temperatures. A desirable system would have selectivity (cf. amine) and high capacity (cf. MOF), but also increased adsorption at higher temperatures. Here, we demonstrate a proof-of-concept where polyethyleneimine (PEI) is converted to a high capacity and highly selective CO2 absorbent using buckminsterfullerene (C60) as a cross-linker. PEI-C60 (CO2 absorption of 0.14 g/g at 0.1 bar/90°C) is compared to one of the best MOFs, Mg-MOF-74 (0.06 g/g at 0.1 bar/90°C), and does not absorb any measurable amount of CH4 at 50 bar. Thus, PEI-C60 can perform better than MOFs in the sweetening of natural gas

    Classic yin and yang tonic formula for osteopenia: study protocol for a randomized controlled trial

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    <p>Abstract</p> <p>Background</p> <p>Osteoporosis is a growing worldwide problem, with the greatest burden resulting from fractures. Nevertheless, the majority of fractures in adults occur in those with "osteopenia" (bone mineral density (BMD) only moderately lower than young normal individuals). Since long-term drug therapy is an expensive option with uncertain consequences and side effects, natural herbal therapy offers an attractive alternative. The purpose of this study is to evaluate the effect on BMD and safety of the Classic Yin and Yang Tonic Formula for treatment of osteopenia and to investigate the mechanism by which this efficacy is achieved.</p> <p>Methods/design</p> <p>We propose a multicenter double-blind randomized placebo-controlled trial to evaluate the efficacy and safety of the Classic Yin and Yang Tonic Formula for the treatment of osteopenia. Participants aged 55 to 75 with low bone mineral density (T-score between -1 and -2.5) and kidney deficiency in TCM will be included and randomly allocated into two groups: treatment group and control group. Participants in the treatment group will be treated with Classic Yin and Yang Tonic Granule, while the controlled group will receive placebo. Primary outcome measure will be BMD of the lumbar spine and proximal femur using dual-energy X-ray absorptiometry. Secondary outcomes will include pain intensity measured with visual analogue scales, quality of life, serum markers of bone metabolism, indices of Neuro-endocrino-immune network and safety.</p> <p>Discussion</p> <p>If the Classic Yin and Yang Tonic Formula can increase bone mass without adverse effects, it may be a novel strategy for the treatment of osteoporosis. Furthermore, the mechanism of the Chinese medical formula for osteoporosis will be partially elucidated.</p> <p>Trial registration</p> <p>This study is registered at ClinicalTrials.gov, <a href="http://www.clinicaltrials.gov/ct2/show/NCT01271647">NCT01271647</a>.</p

    A Phos-Tag-Based Approach Reveals the Extent of Physiological Endoplasmic Reticulum Stress

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    Cellular response to endoplasmic reticulum (ER) stress or unfolded protein response (UPR) is a key defense mechanism associated with many human diseases. Despite its basic and clinical importance, the extent of ER stress inflicted by physiological and pathophysiological conditions remains difficult to quantitate, posing a huge obstacle that has hindered our further understanding of physiological UPR and its future therapeutic potential. Here we have optimized a Phos-tag-based system to detect the activation status of two proximal UPR sensors at the ER membrane. This method allowed for a quantitative assessment of the level of stress in the ER. Our data revealed quantitatively the extent of tissue-specific basal ER stress as well as ER stress caused by the accumulation of misfolded proteins and the fasting-refeeding cycle. Our study may pave the foundation for future studies on physiological UPR, aid in the diagnosis of ER-associated diseases and improve and facilitate therapeutic strategies targeting UPR in vivo
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