55,432 research outputs found
Recommended from our members
Characterisation of the UV environment of the Beagle 2 landing site
A study of the UV environment of the Beagle 2 landing site has been carried out. An instrument to measure the UV flux is present on the lander, and this work serves to aid in the interpretation of expected data
Investigating microstructural variation in the human hippocampus using non-negative matrix factorization
In this work we use non-negative matrix factorization to identify patterns of microstructural variance in the human hippocampus. We utilize high-resolution structural and diffusion magnetic resonance imaging data from the Human Connectome Project to query hippocampus microstructure on a multivariate, voxelwise basis. Application of non-negative matrix factorization identifies spatial components (clusters of voxels sharing similar covariance patterns), as well as subject weightings (individual variance across hippocampus microstructure). By assessing the stability of spatial components as well as the accuracy of factorization, we identified 4 distinct microstructural components. Furthermore, we quantified the benefit of using multiple microstructural metrics by demonstrating that using three microstructural metrics (T1-weighted/T2-weighted signal, mean diffusivity and fractional anisotropy) produced more stable spatial components than when assessing metrics individually. Finally, we related individual subject weightings to demographic and behavioural measures using a partial least squares analysis. Through this approach we identified interpretable relationships between hippocampus microstructure and demographic and behavioural measures. Taken together, our work suggests non-negative matrix factorization as a spatially specific analytical approach for neuroimaging studies and advocates for the use of multiple metrics for data-driven component analyses
Dynamic analysis using superelements for a large helicopter model
Using superelements (substructures), modal and frequency response analysis was performed for a large model of the Advanced Attack Helicopter developed for the U.S. Army. Whiffletree concept was employed so that the residual structure along with the various superelements could be represented as beam-like structures for economical and accurate dynamic analysis. A very large DMAP alter to the rigid format was developed so that the modal analysis, the frequency response, and the strain energy in each component could be computed in the same run
Migrating agile methods to standardized development practice
Situated process and quality frame-works offer a way to resolve the tensions that arise when introducing agile methods into standardized software development engineering. For these to be successful, however, organizations must grasp the opportunity to reintegrate software development management, theory, and practice
Recommended from our members
The use of platelet-rich plasma in treatment of olfactory dysfunction: A pilot study.
BackgroundOlfactory dysfunction is a prevalent problem with a significant impact on quality of life and increased mortality. Limited effective therapies exist. Platelet-rich plasma (PRP) is an autologous biologic product with anti-inflammatory and neuroprotective effects. This novel pilot study evaluated the role of PRP on olfactory neuroregeneration in patients with hyposmia.MethodsSeven patients who had olfactory loss greater than 6 months in duration, no evidence of sinonasal inflammatory disease, and no improvement with olfactory training and budesonide topical rinses were enrolled in this preliminary study. Patients received a single intranasal injection of PRP into the mucosa of the olfactory cleft. The Sniffin' Sticks olfactory test consisting of threshold, discrimination, and identification measurements (TDI) was administered at the beginning of the study and at 1 and 3 months.ResultsAll patients reported a subjective improvement of their smell shortly after injection but then stabilized. At 3-month post-treatment, two patients with functional anosmia (TDI < 16) did not improve significantly. Five patients with hyposmia (TDI > 16 but <30) showed an improvement with 60% achieving normosmia (TDI > 30) at 3-month follow-up. On average, patients with baseline TDI > 16 improved by 5.85 points with the most significant improvement in the threshold subcomponent. There were no adverse outcomes from intranasal PRP injections.ConclusionPRP appears safe for use in the treatment of olfactory loss, and preliminary data suggest possible efficacy, especially for those with moderate yet persistent loss. Further studies will help determine optimal frequency and duration of use.Level of evidence 2
Recommended from our members
A miniature UV-VIS spectrometer for the surface of Mars
A miniature spectrometer is in the process of development for a future Mars mission, to measure the UV-VIS spectrum encountered at the martian surface. With an intended mass of ~100 g, the spectrometer is planned as part of the ESA ExoMars mission
Recommended from our members
A close encounter with a terrestrial dust devil
We report on an extremely well characterised encounter with a terrestrial dust devil, and its comparison with martian dust devils
DEVELOPMENT AND VALIDATION OF STABILITY INDICATING CHROMATOGRAPHIC METHOD FOR SIMULTANEOUS ESTIMATION OF SACUBITRIL AND VALSARTAN IN PHARMACEUTICAL DOSAGE FORM
Objective: This study aims to develop and validate a stability indicating HPLC method for simultaneous estimation of sacubitril and valsartan in pharmaceutical dosage form.Methods: Sacubitril and valsartan separation were achieved by LC-20 AT C18 (250 mm x 4.6 mm) column and buffer (potassium phosphate, pH 3.0): methanol (50:50) as mobile phase, at a flow rate of 1 ml/min (millilitre per minute). Detection was carried out at 224 nm (nanometer). The different HPLC experimental parameters were optimized and the method was validated according to the standard guideline. Forced degradation experiments were carried out by exposing sacubitril and valsartan standard and sample for thermal, photolytic, oxidative and acid-base hydrolytic stress conditions.Results: Retention time of sacubitril and valsartan were found to be 4.170 min (minute) and 6.530 min (minute) respectively. The method has been validated for linearity, accuracy, precision, LOD, and LOQ. Linearity observed for sacubitril is 12.25-36.75 μg/ml (microgram per milliliter) and for valsartan is 12.75-38.25 μg/ml (microgram per milliliter). The results showed that sacubitril and valsartan and the other degradation products were fully resolved and thus the proposed method is stability-indicating.Conclusion: The proposed HPLC method was found to be simple, specific, precise, accurate, rapid and economical for simultaneous estimation of valsartan and sacubitril in bulk and tablet dosage form. Thus the validated economical method was applied for forced degradation study of sacubitril and valsartan tablet
Stronger inflammatory/cytotoxic T cell response in women identified by microarray analysis
Women develop chronic inflammatory autoimmune diseases like lupus more often than men. The mechanisms causing the increased susceptibility are incompletely understood, although estrogen is believed to contribute. Chronic immune stimulation characterizes many autoimmune disorders. We hypothesized that repeated stimulation may cause a different T cell immune response in women than men. Microarray approaches were used to compare gene expression in T cells from healthy men and women with and without repeated stimulation. Four days following a single stimulation only 25% of the differentially expressed, gender-biased genes were expressed at higher levels in the women. In contrast, following restimulation 72% were more highly expressed in women. Immune response genes were significantly over-represented among the genes upregulated in women, and among the immune response genes, the inflammatory/cytotoxic effector genes interferon gamma (IFNG), lymphotoxin beta (LTB), granzyme A (GZMA), interleukin-12 receptor beta2 (IL12RB2), and granulysin (GNLY) were among those overexpressed to the greatest degree. In contrast, IL17A was the only effector gene more highly expressed in men. Estrogen response elements were identified in the promoters of half of the overexpressed immune genes in women, and in <10% of the male biased genes. The differential expression of inflammatory/cytotoxic effector molecules in restimulated female T cells may contribute to the differences in autoimmune diseases between women and men
- …