1,557 research outputs found
Tank construction for space vehicles Patent
Liquid propellant tank design with semitoroidal bulkhea
Interconversion of Prony series for relaxation and creep
Various algorithms have been proposed to solve the interconversion equation of linear viscoelasticity when Prony series are used for the relaxation and creep moduli, G(t) and J(t). With respect to a Prony series for G(t), the key step in recovering the corresponding Prony series for J(t) is the determination of the coefficients {jk} of terms in J(t). Here, the need to solve a poorly conditioned matrix equation for the {jk} is circumvented by deriving elementary and easily evaluated analytic formulae for the {jk} in terms of the derivative dG(s)/ds of the Laplace transform G(s) of G(t)
Age-related cognitive decline and the olfactory identification deficit are associated to increased level of depression
Purpose: Previous studies reported a correlation between olfactory function and depression. However, in literature, no data are available for the correlation between depression and all other factors such as age, sex, olfactory, gustatory, and cognitive function in healthy subjects taken together. The aim of this study was to provide a systematic account regarding the association between those variables in a nonclinical population.
Methods: Two hundred and seventy-three participants were recruited with an age range of 19–84 years. Olfactory, gustatory, cognitive function, and depression level were evaluated by means of the following tests: the Sniffin’ Sticks test, Taste Strips test, Montreal Cognitive Assessment (MoCA), and Beck Depression Inventory (BDI).
Results: In our data, an age-related decrease in olfactory and gustatory function and a decline in cognitive functions such as attention, memory, and language were observed. Instead, no significant differences were observed for the depression level in relation to the different age ranges. However, our results indicated that the depression level could be associated to sex, odor identification impairment, and decreased attention and language.
Conclusion: Sex, the odor identification impairment, and an age-related decrease in attention and language are associated with increased level of depression in healthy subjects. Our data can be useful and informative for health care workers, that is, to have adequate preventive strategies to be used whenever these conditions are detected and recognized
Management of dyslipidaemia in an HIV-positive cohort
Background: Dyslipidaemia, secondary to both HIV and the use of antiretroviral therapy (ART) is well recognised, with HIV replication and immune status also thought to contribute to the risk. Traditionally the HIV physician has looked after HIV with primary care physicians (GP) managing non-HIV-related medical issues. However with the ageing population and the effectiveness of ART the HIV physician is diversifying to focus management strategies on preventative measures also. Method: 127 subjects were recruited. All subjects were HIV-positive males without any traditional cardiovascular disease symptoms or history. Details of patients demographics, family history, statin therapy, and primary care physician contact were collected. Baseline parameters were recorded and fasting bloods taken. Results: 127 asymptomatic HIV-positive males were recruited. 74/127 (58.3%) met the EACS criteria for statin prescription. 33/74 (44.6%) were on a statin. There was no significant difference between the class of antiretroviral prescribed, (NNRTI v PI) and lipid abnormalities (p=0.628). Hypertension and increased waist:hip ratio significantly increased the chances of the patient being hyperlipidaemic. Patients were more likely to be prescribed a statin if they were older, had hypertension, an increased waist circumference, increased Framingham risk, increased brain natriuretic peptide (BNP), or were diagnosed HIV-positive for longer (p<0.05). Pravastatin (21/33 [63.6%]), was most commonly prescribed statin. 24.2% received their statin prescription from their HIV physician, with 75.8% receiving their prescription from their GP. 5/21 (23.8%) on pravastatin met the target verses 7/7 (100%) on atorvastatin verses 2/2 (100%) on simvastatin versus 1/3 (33.3%) on rosuvastatin (p=0.02). Meeting lipid targets was less successful in the protease inhibitor group (1/9) 11.1% versus 11/21 (52.4%) in the NNRTI group (p=0.16). Conclusion: The majority met criteria for lipid management but less than half of those were prescribed it. Of those, most received treatment from their GP. Nearly half of those on statins did not meet lipid targets. HIV physicians were most likely to prescribe pravastatin and those on pravastatin were the least likely to achieve lipid targets when compared to the other statins. HIV physicians need to diversify their knowledge base and have clearly defined management strategies for the management of dyslipidaemia
STZ-diabetic rat heart maintains developed tension amplitude by increasing sarcomere length and crossbridge density
New Findings: What is the central question of this study? In the papillary muscle from type I diabetic rats, does diabetes-associated altered ventricular function result from changes of acto-myosin interactions and are these modifications attributable to a possible sarcomere rearrangement? What is the main finding and its importance? For the first time, we showed that type-I diabetes altered sarcomeric ultrastructure, as seen by transmission electron microscopy, consistent with physiological parameters. The diabetic condition induced slower timing parameters, which is compatible with a diastolic dysfunction. At the sarcomeric level, augmented β-myosin heavy chain content and increased sarcomere length and crossbridges' number preserve myocardial stroke and could concur to maintain the ejection fraction. Abstract: We investigated whether diabetes-associated altered ventricular function, in a type I diabetes animal model, results from a modification of acto-myosin interactions, through the in vitro recording of left papillary muscle mechanical parameters and examination of sarcomere morphology by transmission electron microscopy (TEM). Experiments were performed on streptozotocin-induced diabetic and age-matched control female Wistar rats. Mechanical isometric and isotonic indexes and timing parameters were determined. Using Huxley's equations, we calculated mechanics, kinetics and energetics of myosin crossbridges. Sarcomere length and A-band length were measured on TEM images. Type I and III collagen and β-myosin heavy chain (MHC) expression were determined by immunoblotting. No variation in resting and developed tension or maximum extent of shortening was evident between groups, but diabetic rats showed lower maximum shortening velocity and prolonged timing parameters. Compared to controls, diabetics also displayed a higher number of crossbridges with lower unitary force. Moreover, no change in type I and III collagen was associated to diabetes, but pathological rats showed a two-fold enhancement of β-MHC content and longer sarcomeres and A-band, detected by ultrastructural morphometry. Overall, these data address whether a preserved systolic function accompanied by an altered diastolic phase results from a recruitment of super-relaxed myosin heads or the phosphorylation of the regulatory light chain site in myosin. Although the early signs of diabetic cardiomyopathy were well expressed, the striking finding of our study was that, in diabetics, sarcomere modification may be a possible compensatory mechanism that preserves systolic function
Avaliação do potencial produtivo da videira Niágara Rosada na Região de Pelotas.
O Objetivo do trabalho é avaliar a produção de videira ?Niágara Rosada? na região de Pelotas, com e sem a utilização da cobertura da parreiral com plástico transparente
Late gadolinium enhancement and subclinical cardiac dysfunction on cardiac MRI in asymptomatic HIV-positive men
Background: HIV is associated with an increased risk of cardiovascular disease (CVD) and related clinical events. While traditional risk factors play an important role in the pathology of cardiovascular disease, HIV infection and its sequelae of immune activation and inflammation may have significant effects on the myocardium before becoming clinically evident. Cardiac MRI (CMR) can be used to detect the pattern of these subclinical changes. This will lead to a better understanding of risk factors contributing to cardiovascular disease prior to it becoming clinically significant in HIV-positive patients. Methods: Prospective cohort study of 127 asymptomatic HIV-positive men on ART compared to 35 matched controls. Baseline demographics, HIV parameters, 12-lead ECG, routine biochemistry, and traditional cardiovascular risk factors were recorded. Images were acquired on a 3T Achieva Philips MRI scanner with 5 channel phase array cardiac coil and weight-based IV gadolinium was given at 0.15 mmol/kg dose with post-contrast inversion recovery imaging after 10 minutes. Results: 6/127 (4.7%) of asymptomatic HIV-positive men had late gadolinium enhancement (LGE) on MRI verses 1/35 (2.9%) in the control group. In 3/6 (50%) of cases this was in a classical infarction pattern with subendocardial involvement. 3/6 (50%) were consistent with prior myocarditis. There was no significant difference in mean LVEF (66.93% vs 65.18%), LVMI (60.05g/m2 vs 55.94g/m2) or posterolateral wall thickness (8.28 mm and 8.16 mm) between cases and controls respectively. There was significantly more diastolic dysfunction, E:A ratio < 1, found in the HIV-positive group, 18% vs 7% of controls (p = 0.037). Framingham risk did not predict either of these outcomes. Conclusions: There is an increased incidence of LGE detected on CMR in this asymptomatic HIV-positive cohort. Two distinct pathological processes were identifed as causing these changes, myocardial infarction and myocarditis. These findings were independent of traditional cardiac risk factors, duration of HIV infection and ART therapy. Sub clinical cardiac dysfunction may be underreported in other cardiac evaluation studies. The true impact of other potential risk factors may also be underestimated, highlighting the need for the development of more complex prediction models
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