737 research outputs found
Isolation of Acanthamoeba isolates belonging to T2, T3, T4 and T7 genotypes from environmental samples in Ankara, Turkey
Acanthamoeba keratitis is a blinding infection that is becoming increasingly important in human health. Early diagnosis is a prerequisite for successful treatment and requires identification of Acanthamoeba at the genotypic level. The genus Acanthamoeba consists of both pathogenic and non-pathogenic species and has been recently classified into 13 different genotypes, T1-T12 and T14. More importantly, 95% of Acanthamoeba isolates that produce keratitis belong to T4 genotypes. In this study, we attempted to determine whether predominance of T4 isolates in Acanthamoeba keratitis is due to greater virulence or greater prevalence. We isolated 18 Acanthamoeba isolates from environmental samples in Ankara, Turkey and determined their pathogenic potential by means osmotolerance, temperature tolerance and in vitro cytotoxicity assays using corneal epithelial cells. Ribosomal DNA sequencing revealed that 10 isolates belong to T2, 5 belong to T3, 2 belong to T4 and one belongs to T7 genotype. As expected, T3 and T4 isolates exhibited the most pathogenic traits and were osmotolerant, temperature tolerant and exhibited severe corneal epithelial cell cytotoxicity indicating their pathogenic potential. Overall these data indicate that high frequency of T4 isolates in keratitis cases may well be due to their greater virulence. This is the first report presenting environmental distribution of Acanthamoeba in Ankara, Turkey
Acanthamoeba castellanii induces host cell death via a phosphatidylinositol 3-kinase-dependent mechanism
Granulomatous amoebic encephalitis due to Acanthamoeba castellanii is a serious human infection with fatal consequences, but it is not clear how the circulating amoebae interact with the blood-brain barrier and transmigrate into the central nervous system. We studied the effects of an Acanthamoeba encephalitis isolate belonging to the T1 genotype on human brain microvascular endothelial cells, which constitute the blood-brain barrier. Using an apoptosis-specific enzyme-linked immunosorbent assay, we showed that Acanthamoeba induces programmed cell death in brain microvascular endothelial cells. Next, we observed that Acanthamoeba specifically activates phosphatidylinositol 3-kinase. Acanthamoeba-mediated brain endothelial cell death was abolished using LY294002, a phosphatidylinositol 3-kinase inhibitor. These results were further confirmed using brain microvascular endothelial cells expressing dominant negative forms of phosphatidylinositol 3-kinase. This is the first demonstration that Acanthamoeba-mediated brain microvascular endothelial cell death is dependent on phosphatidylinositol 3-kinase
Emotional fit: developing a new fashion design methodology for mature women
This paper reports on a user-centered methodological approach towards fashion design for mature women (55+). Referred to as the 'baby boomers' the women in this study are the product of the cultural revolution of the 1960s, who consequently have a strong sense of their own 'agency', as conveyed through their clothing and style, but now find themselves stepping into the unknown territory of a limited market. The majority of fashion brands and stores are aimed at younger consumers, and with some exceptions, it is only high and niche designer labels who are offering stylish garments that complement the changing bodies of an older generation women with strong aesthetic values. In response to this situation three researchers have developed an original research methodology which synthesizes fashion and textile design practices with Interpretative Phenomenological Analysis (IPA), resulting in an holistic, co-design and user-centred approach that responds to the emotional and physical needs of an ageing female demographic
Dynamic landscape changes in Glen Roy and vicinity, west Highland Scotland, during the Younger Dryas and early Holocene:a synthesis
State-of-the-art in studies of glacial isostatic adjustment for the British Isles: a literature review
Understanding the effects of glacial isostatic adjustment (GIA) of the British Isles is essential for the assessment of past and future sea-level trends. GIA has been extensively examined in the literature, employing different research methods and observational data types. Geological evidence from palaeo-shorelines and undisturbed sedimentary deposits has been used to reconstruct long-term relative sea-level change since the Last Glacial Maximum. This information derived from sea-level index points has been employed to inform empirical isobase models of the uplift in Scotland using trend surface and Gaussian trend surface analysis, as well as to calibrate more theory-driven GIA models that rely on Earth mantle rheology and ice sheet history. Furthermore, current short-term rates of GIA-induced crustal motion during the past few decades have been measured using different geodetic techniques, mainly continuous GPS (CGPS) and absolute gravimetry (AG). AG-measurements are generally employed to increase the accuracy of the CGPS estimates. Synthetic aperture radar interferometry (InSAR) looks promising as a relatively new technique to measure crustal uplift in the northern parts of Great Britain, where the GIA-induced vertical land deformation has its highest rate. This literature review provides an in-depth comparison and discussion of the development of these different research approaches
Does sorption of sulfuryl fluoride by wheat reduce its efficacy against adults and eggs of Rhyzopertha dominica?
Despite its growing importance as a fumigant for grain, there is no information on the impact of sorption on the efficacy of sulfuryl fluoride (SF) against target insect pests. Eggs and adults of a major grain pest, Rhyzopertha dominica, living in wheat (12% m.c.), were fumigated with SF at 0.5, 1, and 2 mg/L for 168 h at 25 °C. Sorption of the fumigant by the grain followed an exponential decay and reduced the mortality rates of both adults and eggs. The partition ratio (K), a measure of physical sorption, had a strong impact on mortality of both adults and eggs. The quadratic model showed the best fit to the data and turning points in the relationship indicated that although mortality increased as concentration increased, physical sorption removed fumigant resulting in a decrease in the mortality rate. There was a linear relationship between mortality and the rate of sorption (k) of SF by the wheat. At each concentration, mortality rate increased as k increased despite sorption continuing, indicating that the chemical sorption rate had little impact on mortality. Sorption of SF into the commodity has the potential to reduce the biological efficacy of the fumigant resulting in potential control failures. Concentration x time protocols may need to be revised to account for this phenomenon
Application of Radarsat imagery on grassland heterogeneity assessment
Non-Peer ReviewedHeterogeneity, the degree of dissimilarity, is one of the most important and widely applicable concepts in ecology. It is highly related to ecosystem condition and wildlife habitat. In this study, the feasibility of applying Radarsat-1 HH polarization Synthetic Aperture Radar (SAR) image on heterogeneity study is tested on the Grasslands National Park (GNP) and surrounding pastures. GNP is located in southern Saskatchewan along the international boundary of Canada and the United States, which represents northern mixed grasslands. Fieldwork was conducted at GNP and surrounding pastures from June to July,
2003. Biophysical variables including species composition, cover, biomass, and canopy height were collected from 10 sites. Height heterogeneity index, Shannon’s index, and standard deviation were calculated based on field data. One standard mode Radarsat-1 HH image acquired on August 1, 2003 was used for this study. Parameters from texture analysis and standard deviation of the backscatters are correlated with biophysical parameters to measure grasslands heterogeneity. Results showed that different parameters had various abilities to detect field heterogeneity. Correlation showed the highest ability to explain variation of bareground cover (79%). Mean and contrast can also be utilized to explain the variation of grass biomass and standing dead cover (59% and 56% respectively)
Compact structure and proteins of pasta retard in vitro digestive evolution of branched starch molecular structure
The roles that the compact structure and proteins in pasta play in retarding evolution of starch molecular structure during in vitro digestion are explored, using four types of cooked samples: whole pasta, pasta powder, semolina (with proteins) and extracted starch without proteins. These were subjected to in vitro digestion with porcine alpha-amylase, collecting samples at different times and characterizing the weight distribution of branched starch molecules using size-exclusion chromatography. Measurement of alpha-amylase activity showed that a protein (or proteins) from semolina or pasta powder interacted with alpha-amylase, causing reduced enzymatic activity and retarding digestion of branched starch molecules with hydrodynamic radius (R-h) 100 nm. (C) 2016 Elsevier Ltd. All rights reserved
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