497 research outputs found
Selectivity of interaction of spin-labelled lipids with peripheral proteins bound to dimyristoylphosphatidylglycerol bilayers, as determined by ESR spectroscopy.
The selectivity of interaction between spin-labelled lipids and the peripheral proteins, apocytochrome c, cytochrome c, lysozyme and polylysine has been studied using ESR spectroscopy. Derivatives of phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), phosphatidylserine (PS), phosphatidylinositol (PI), diphosphatidylglycerol (CL) and diacylglycerol (DG) spin-labelled at the 5-C atom position of the sn-2 chain were used to study the association of these proteins with bilayers of dimyristoylphosphatidylglycero. Binding of the proteins increased the outer hyperfine splitting in the ESR spectra of the lipid spin labees to an extent which depended both on the spin-labelled lipid species involved and on the particular protein. The order of selectivity for apocytochrome c follows the sequence: PI−>CL−≈DG PS−>PC±>PG−>PE±. The selectivity pattern for cytochrome c is: PI−>PG−>CL−>DG PS−≈PC±>PE±; for lysozyme is: CL−>PG−>DG PE−>PC±PS−>PI−; and that for polylysine is: CL−>PS−⩾PG−>PI−>PC±>DG PE+-. The overall strength of interaction is in the order lysozyme>cytochrome c>apcoytochrome c, for equivalent binding, and the spread of the selectivity for the different proteins is in the reverse order. Assuming fast exchange for the ESR spectra of the 5-C atom labelled lipids, the relative association constants of the different labels with the different proteins have been estimated
Specificity of the interaction of amino- and carboxy-terminal fragments of the mitochondrial precursor protein apocytochrome c with negatively charged phospholipids. A spin-label electron spin resonance study.
An Experimental Investigation Into the Performance of a Flush Water-Jet Inlet
An experimental investigation of the flow within a generic flush type water-jet inlet has
been carried out to identify the principal flow features and provide a basis for development
of computational fluid dynamics (CFD) models. Tests were performed in a
cavitation tunnel with the model inlet fitted to the test section ceiling, and effects of
thickening the ingested tunnel wall boundary layer were investigated. The model was
fitted with a range of instrumentation to investigate the ramp pressure distribution and
boundary layer development, lip incidence, and pump face flow properties. Observations
of lip and duct cavitation inception and behavior were also made. The results
showed the inlet performance to be generally improved with the ingestion of a thicker
boundary layer. The thickened boundary layer significantly reduced ramp boundary
layer separation and distortion of flow at the notional pump face. However, a greater
range of lip incidence occurred with the thickened boundary layer with consequent
greater likelihood of lip separation and cavitation occurrence. Ideal lip incidence and
pump face flow uniformity occurred at flow parameters significantly different from
those for ideal pump face pressure recovery. Large developed cavities on the inlet lip
were observed for a range of conditions typical of conventional high-speed vessel
operation
Національні тенденції розвитку університетської освіти
В сучасному динамічно змінюваному світі університет - це перш за все вищий навчальний заклад, який є індикатором цивілізаційності регіону та держави. Проте у наші дні класичні університети постали перед серйозними викликами часу.В современном динамически изменяющемся мире университет - это прежде всего высшее учебное заведение, которое является индикатором цивилизационности региона и государства. Однако в наши дни классические университеты встали перед серьезными вызовами времени
Focal Thyroid Incidentalomas on F-18-FDG PET/CT:A Systematic Review and Meta-Analysis on Prevalence, Risk of Malignancy and Inconclusive Fine Needle Aspiration
BackgroundThe rising demand for 18F-fluorodeoxyglucose positron emission tomography with computed tomography (18F-FDG PET/CT) has led to an increase of thyroid incidentalomas. Current guidelines are restricted in giving options to tailor diagnostics and to suit the individual patient.ObjectivesWe aimed at exploring the extent of potential overdiagnostics by performing a systematic review and meta-analysis of the literature on the prevalence, the risk of malignancy (ROM) and the risk of inconclusive FNAC (ROIF) of focal thyroid incidentalomas (FTI) on 18F-FDG PET/CT.Data SourcesA literature search in MEDLINE, Embase and Web of Science was performed to identify relevant studies.Study SelectionStudies providing information on the prevalence and/or ROM of FTI on 18F-FDG PET/CT in patients with no prior history of thyroid disease were selected by two authors independently. Sixty-one studies met the inclusion criteria.Data AnalysisA random effects meta-analysis on prevalence, ROM and ROIF with 95% confidence intervals (CIs) was performed. Heterogeneity and publication bias were tested. Risk of bias was assessed using the quality assessment of diagnostic accuracy studies (QUADAS-2) tool.Data SynthesisFifty studies were suitable for prevalence analysis. In total, 12,943 FTI were identified in 640,616 patients. The pooled prevalence was 2.22% (95% CI = 1.90% - 2.54%, I2 = 99%). 5151 FTI had cyto- or histopathology results available. The pooled ROM was 30.8% (95% CI = 28.1% - 33.4%, I2 = 57%). 1308 (83%) of malignant nodules were papillary thyroid carcinoma (PTC). The pooled ROIF was 20.8% (95% CI = 13.7% - 27.9%, I2 = 92%).LimitationsThe main limitations were the low to moderate methodological quality of the studies and the moderate to high heterogeneity of the results.ConclusionFTI are a common finding on 18F-FDG PET/CTs. Nodules are malignant in approximately one third of the cases, with the majority being PTC. Cytology results are non-diagnostic or indeterminate in one fifth of FNACs. These findings reveal the potential risk of overdiagnostics of FTI and emphasize that the workup of FTI should be performed within the context of the patient’s disease and that guidelines should adopt this patient tailored approach
Resistance of Gram-positive bacteria to nisin is not determined by Lipid II levels
Lipid II is essential for nisin-mediated pore formation at nano-molar concentrations. We tested whether nisin resistance could result from different Lipid II levels, by comparing the maximal Lipid II pool in Micrococcus flavus (sensitive) and Listeria monocytogenes (relatively insensitive) and their nisin-resistant variants, with a newly developed method. No correlation was observed between the maximal Lipid II pool and nisin sensitivity, as was further corroborated by using spheroplasts of nisin-resistant and wild-type strains of M. flavus, which were equally sensitive to nisin. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved
Adding diagnostic laparoscopy to computed tomography for the evaluation of peritoneal metastases in patients with colorectal cancer:A retrospective cohort study
Background: Despite its widespread use, computed tomography (CT) is not perfect for evaluating peritoneal metastases of colorectal origin before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). We therefore evaluated the value of adding diagnostic lapamscopy to CT when assessing patient eligibility for CRS + HIPEC. Methods: This was a retrospective study of a consecutive series of 112 patients evaluated systematically by diagnostic laparoscopy and CT between January 2012 and January 2018. Patient eligibility for CRS + HIPEC was assessed by the peritoneal cancer index (PCI) both at the time of initial diagnostic lapamscopy and during the retrospective review of CT images. Two experienced radiologists who were blinded to the PCI result at laparoscopy then independently estimated the PCI based on CT imaging. The primary outcome was the number of patients eligible for CRS + HIPEC by each method. Results: We identified 112 patients, of whom 95 (85%) were eligible for CRS + HIPEC based on diagnostic laparoscopy and 84 underwent CRS + HIPEC. Overall, 14 patients (17%) experienced an "open-and-close" procedure. In contrast to diagnostic lapamscopy, 100 patients (89%) were identified as being eligible for CRS + HIPEC by CT (p = 0.13), which would have resulted in an additional five open-and-close procedures. Conclusions: Adding diagnostic laparoscopy to CT produced a clinically relevant, but statistically non-significant, reduction in the number of patients eligible for CRS + HIPEC. We conclude that diagnostic lapamscopy may be of use in preoperative assessments when systematic analysis by CT scores the PCI as greater than ten. Future research should focus on the cost-effectiveness of this approach
Systematic Review of Factors Affecting Quality of Life After Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy
Background: Previous studies have shown that, overall, quality of life (QoL) decreases within the first 3–6 months after cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC), returning to baseline levels by 6–12 months. This systematic review aims to evaluate the factors affecting QoL after CRS + HIPEC within 12 months of surgery. Methods: Electronic databases were investigated searching for articles reporting QoL with validated questionnaires up to September 2019. Risk of bias was assessed with the methodological index for non-randomized studies tool. The primary outcomes were short-term (< 6 months after surgery) and medium-term (6–12 months after surgery) determinants of QoL after CRS + HIPEC. Secondary outcomes were QoL and reported symptoms over time. Results: We included 14 studies that used 12 different questionnaires. The reported data were collected prospectively or retrospectively for 1556 patients (dropout < 50% in four studies). Overall, studies showed diminished QoL within 3 months after surgery and a recovery to baseline or greater by 12 months. QoL was negatively influenced by higher age, female sex, prolonged operation time, extensive disease, residual disease, adjuvant chemotherapy, complications, stoma placement, and recurrent disease. QoL results were comparable between studies, with dropout rates above and below 50%. Conclusions: QoL returns to baseline levels within 12 months after CRS + HIPEC provided the disease does not recur, and this recovery process is influenced by several factors
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