4,333 research outputs found
Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data
The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l-1) could be reliably estimated. In this study, we developed a semi-empirical radiative transfer (SERT) model with physically based empirical coefficients to estimate SSC from MERIS data over turbid waters with a much wider range of SSC. The model was based on the Kubelka–Munk two-stream approximation of radiative transfer theory and calibrated using datasets from in situ measurements and outdoor controlled tank experiments. The results show that the sensitivity and saturation level of remote-sensing reflectance to SSC are dependent on wavelengths and SSC levels. Therefore, the SERT model, coupled with a multi-conditional algorithm scheme adapted to satellite retrieval of wide-range SSC, was proposed. Results suggest that this method is more effective and accurate in the estimation of SSC over turbid water
Effective health care for older people resident in care homes: the optimal study protocol for realist review
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Care homes in the UK rely on general practice for access to specialist medical and nursing care as well as referral to therapists and secondary care. Service delivery to care homes is highly variable in both quantity and quality. This variability is also evident in the commissioning and organisation of care home-specific services that range from the payment of incentives to general practitioners (GPs) to visit care homes, to the creation of care home specialist teams and outreach services run by geriatricians. No primary studies or systematic reviews have robustly evaluated the impact of these different approaches on organisation and resident-level outcomes. Our aim is to identify factors which may explain the perceived or demonstrated effectiveness of programmes to improve health-related outcomes in older people living in care homes. Methods/Design: A realist review approach will be used to develop a theoretical understanding of what works when, why and in what circumstances. Elements of service models of interest include those that focus on assessment and management of residents’ health, those that use strategies to encourage closer working between visiting health care providers and care home staff, and those that address system-wide issues about access to assessment and treatment. These will include studies on continence, dignity, and speech and language assessment as well as interventions to promote person centred dementia care, improve strength and mobility, and nutrition. The impact of these interventions and their different mechanisms will be considered in relation to five key outcomes: residents’ medication use, use of out of hours’ services, hospital admissions (including use of Accident and Emergency) and length of hospital stay, costs and user satisfaction. An iterative three-stage approach will be undertaken that is stakeholder-driven and optimises the knowledge and networks of the research team. Discussion: This realist review will explore why and for whom different approaches to providing health care to residents in care homes improves access to health care in the five areas of interest. It will inform commissioning decisions and be the basis for further research. This systematic review protocol is registered on the PROSPERO database reference number: CRD42014009112NIHR Health Services & Delivery Research Programme. Project number 11/1021/0
Access to recreational physical activities by car and bus : an assessment of socio-spatial inequalities in mainland Scotland
Obesity and other chronic conditions linked with low levels of physical activity (PA) are associated with deprivation. One reason for this could be that it is more difficult for low-income groups to access recreational PA facilities such as swimming pools and sports centres than high-income groups. In this paper, we explore the distribution of access to PA facilities by car and bus across mainland Scotland by income deprivation at datazone level. GIS car and bus networks were created to determine the number of PA facilities accessible within travel times of 10, 20 and 30 minutes. Multilevel negative binomial regression models were then used to investigate the distribution of the number of accessible facilities, adjusting for datazone population size and local authority. Access to PA facilities by car was significantly (p<0.01) higher for the most affluent quintile of area-based income deprivation than for most other quintiles in small towns and all other quintiles in rural areas. Accessibility by bus was significantly lower for the most affluent quintile than for other quintiles in urban areas and small towns, but not in rural areas. Overall, we found that the most disadvantaged groups were those without access to a car and living in the most affluent areas or in rural areas
Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections.
Background:
A number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.<p></p>
Methods:
Minimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.<p></p>
Results:
CHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.<p></p>
Conclusions:
Overall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.<p></p>
T helper cell subsets specific for pseudomonas aeruginosa in healthy individuals and patients with cystic fibrosis
Background: We set out to determine the magnitude of antigen-specific memory T helper cell responses to Pseudomonas aeruginosa in healthy humans and patients with cystic fibrosis.
Methods: Peripheral blood human memory CD4+ T cells were co-cultured with dendritic cells that had been infected with different strains of Pseudomonas aeruginosa. The T helper response was determined by measuring proliferation, immunoassay of cytokine output, and immunostaining of intracellular cytokines.
Results: Healthy individuals and patients with cystic fibrosis had robust antigen-specific memory CD4+ T cell responses to Pseudomonas aeruginosa that not only contained a Th1 and Th17 component but also Th22 cells. In contrast to previous descriptions of human Th22 cells, these Pseudomonal-specific Th22 cells lacked the skin homing markers CCR4 or CCR10, although were CCR6+. Healthy individuals and patients with cystic fibrosis had similar levels of Th22 cells, but the patient group had significantly fewer Th17 cells in peripheral blood.
Conclusions: Th22 cells specific to Pseudomonas aeruginosa are induced in both healthy individuals and patients with cystic fibrosis. Along with Th17 cells, they may play an important role in the pulmonary response to this microbe in patients with cystic fibrosis and other conditions
Pneumococcal carriage in sub-Saharan Africa--a systematic review.
BACKGROUND: Pneumococcal epidemiology varies geographically and few data are available from the African continent. We assess pneumococcal carriage from studies conducted in sub-Saharan Africa (sSA) before and after the pneumococcal conjugate vaccine (PCV) era. METHODS: A search for pneumococcal carriage studies published before 2012 was conducted to describe carriage in sSA. The review also describes pneumococcal serotypes and assesses the impact of vaccination on carriage in this region. RESULTS: Fifty-seven studies were included in this review with the majority (40.3%) from South Africa. There was considerable variability in the prevalence of carriage between studies (I-squared statistic = 99%). Carriage was higher in children and decreased with increasing age, 63.2% (95% CI: 55.6-70.8) in children less than 5 years, 42.6% (95% CI: 29.9-55.4) in children 5-15 years and 28.0% (95% CI: 19.0-37.0) in adults older than 15 years. There was no difference in the prevalence of carriage between males and females in 9/11 studies. Serotypes 19F, 6B, 6A, 14 and 23F were the five most common isolates. A meta-analysis of four randomized trials of PCV vaccination in children aged 9-24 months showed that carriage of vaccine type (VT) serotypes decreased with PCV vaccination; however, overall carriage remained the same because of a concomitant increase in non-vaccine type (NVT) serotypes. CONCLUSION: Pneumococcal carriage is generally high in the African continent, particularly in young children. The five most common serotypes in sSA are among the top seven serotypes that cause invasive pneumococcal disease in children globally. These serotypes are covered by the two PCVs recommended for routine childhood immunization by the WHO. The distribution of serotypes found in the nasopharynx is altered by PCV vaccination
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Risk measures for direct real estate investments with non-normal or unknown return distributions
The volatility of returns is probably the most widely used risk measure for real estate. This is rather surprising since a number of studies have cast doubts on the view that volatility can capture the manifold risks attached to properties and corresponds to the risk attitude of investors. A central issue in this discussion is the statistical properties of real estate returns—in contrast to neoclassical capital market theory they are mostly non-normal and often unknown, which render many statistical measures useless. Based on a literature review and an analysis of data from Germany we provide evidence that volatility alone is inappropriate for measuring the risk of direct real estate.
We use a unique data sample by IPD, which includes the total returns of 939 properties across different usage types (56% office, 20% retail, 8% others and 16% residential properties) from 1996 to 2009, the German IPD Index, and the German Property Index. The analysis of the distributional characteristics shows that German real estate returns in this period were not normally distributed and that a logistic distribution would have been a better fit. This is in line with most of the current literature on this subject and leads to the question which indicators are more appropriate to measure real estate risks. We suggest that a combination of quantitative and qualitative risk measures more adequately captures real estate risks and conforms better with investor attitudes to risk. Furthermore, we present criteria for the purpose of risk classification
Behavioural and Cognitive Associations of Short Stature at 5 Years
Objectives To determine the extent to which childhood short stature is associated with cognitive, behavioural and chronic health problems, and whether these problems could be attributed to recognized adverse biological, psychosocial or psychological factors. Methodology At their first antenatal session, 8556 women were enrolled in a prospective study of pregnancy. When their children were 4 and 6 years of age, mothers completed a detailed questionnaire concerning their child's health and behaviour. A Peabody Picture Vocabulary Test-Revised (PPVT-R) was completed by the child at 5 years of age. Z scores were used to categorize height measurements in 3986 children. The relationship of these height categories with the child's health, and behavioural and cognitive problems was then examined. Results No association was found between height and symptoms of chronic disease or behaviour problems in boys or girls. On the unadjusted analysis, mean PPVT-R scores were significantly lower in boys with heights < 3 percentile and 3-10 percentile compared with study children between 10 to 90 percentile (P < 0.01). Scores were similarly significantly lower in girls with heights < 3 percentile and 3-10 percentile (P = 0.01). Even after adjusting for psychosocial and biological confounders, short stature remained a significant predictor for lower PPVT-R scores in both boys and girls, although height only accounted for 1.1% of the variance in scores in boys and 0.5% of the variance in PPVT-R scores in girls. Psychosocial factors had a greater role than height in determining PPVT-R scores at 5 years of age. Conclusions These findings suggest a significant, though small, association between height and PPVT-R scores at 5 years of age, independent of psychosocial disadvantage and known biological risk factors
Simultaneous whole-animal 3D-imaging of neuronal activity using light field microscopy
3D functional imaging of neuronal activity in entire organisms at single cell
level and physiologically relevant time scales faces major obstacles due to
trade-offs between the size of the imaged volumes, and spatial and temporal
resolution. Here, using light-field microscopy in combination with 3D
deconvolution, we demonstrate intrinsically simultaneous volumetric functional
imaging of neuronal population activity at single neuron resolution for an
entire organism, the nematode Caenorhabditis elegans. The simplicity of our
technique and possibility of the integration into epi-fluoresence microscopes
makes it an attractive tool for high-speed volumetric calcium imaging.Comment: 25 pages, 7 figures, incl. supplementary informatio
Hsp90 governs dispersion and drug resistance of fungal biofilms
Fungal biofilms are a major cause of human mortality and are recalcitrant to most treatments due to intrinsic drug resistance. These complex communities of multiple cell types form on indwelling medical devices and their eradication often requires surgical removal of infected devices. Here we implicate the molecular chaperone Hsp90 as a key regulator of biofilm dispersion and drug resistance. We previously established that in the leading human fungal pathogen, Candida albicans, Hsp90 enables the emergence and maintenance of drug resistance in planktonic conditions by stabilizing the protein phosphatase calcineurin and MAPK Mkc1. Hsp90 also regulates temperature-dependent C. albicans morphogenesis through repression of cAMP-PKA signalling. Here we demonstrate that genetic depletion of Hsp90 reduced C. albicans biofilm growth and maturation in vitro and impaired dispersal of biofilm cells. Further, compromising Hsp90 function in vitro abrogated resistance of C. albicans biofilms to the most widely deployed class of antifungal drugs, the azoles. Depletion of Hsp90 led to reduction of calcineurin and Mkc1 in planktonic but not biofilm conditions, suggesting that Hsp90 regulates drug resistance through different mechanisms in these distinct cellular states. Reduction of Hsp90 levels led to a marked decrease in matrix glucan levels, providing a compelling mechanism through which Hsp90 might regulate biofilm azole resistance. Impairment of Hsp90 function genetically or pharmacologically transformed fluconazole from ineffectual to highly effective in eradicating biofilms in a rat venous catheter infection model. Finally, inhibition of Hsp90 reduced resistance of biofilms of the most lethal mould, Aspergillus fumigatus, to the newest class of antifungals to reach the clinic, the echinocandins. Thus, we establish a novel mechanism regulating biofilm drug resistance and dispersion and that targeting Hsp90 provides a much-needed strategy for improving clinical outcome in the treatment of biofilm infections
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