354 research outputs found
An analytical and experimental study of heat transfer in a simulated Martian atmosphere Final report, 1 Nov. 1968 - 15 Oct. 1969
Convective heat transfer in simulated Martian atmospher
A Neural-Network-Based Indoor Positioning System by Using Sectored Antenna Array
This paper presents the development of sectored antenna array and modified probabilistic neural network positioning algorithm for an indoor positioning system (IPS). Firstly, a new hexagonal IPS station is composed of six printed-circuit board Yagi-Uda antennas and Zigbee modules. It is designed to obtain the signals between an object and the station. Then, a modified probabilistic neural network (MPNN) is applied to estimate the accurate position of the object with the signal strength. From the experimental positioning results shown, the developed IPS system has the outperformance in an 8x8 square meters indoor scene. The proposed indoor positioning technique not only has a high positioning accuracy, but also is an effective solution to solve the difficult issue of positioning station deployment
Effect of a reduction in glomerular filtration rate after nephrectomy on arterial stiffness and central hemodynamics: rationale and design of the EARNEST study
Background: There is strong evidence of an association between chronic kidney disease (CKD) and cardiovascular disease. To date, however, proof that a reduction in glomerular filtration rate (GFR) is a causative factor in cardiovascular disease is lacking. Kidney donors comprise a highly screened population without risk factors such as diabetes and inflammation, which invariably confound the association between CKD and cardiovascular disease. There is strong evidence that increased arterial stiffness and left ventricular hypertrophy and fibrosis, rather than atherosclerotic disease, mediate the adverse cardiovascular effects of CKD. The expanding practice of live kidney donation provides a unique opportunity to study the cardiovascular effects of an isolated reduction in GFR in a prospective fashion. At the same time, the proposed study will address ongoing safety concerns that persist because most longitudinal outcome studies have been undertaken at single centers and compared donor cohorts with an inappropriately selected control group.<p></p>
Hypotheses: The reduction in GFR accompanying uninephrectomy causes (1) a pressure-independent increase in aortic stiffness (aortic pulse wave velocity) and (2) an increase in peripheral and central blood pressure.<p></p>
Methods: This is a prospective, multicenter, longitudinal, parallel group study of 440 living kidney donors and 440 healthy controls. All controls will be eligible for living kidney donation using current UK transplant criteria. Investigations will be performed at baseline and repeated at 12 months in the first instance. These include measurement of arterial stiffness using applanation tonometry to determine pulse wave velocity and pulse wave analysis, office blood pressure, 24-hour ambulatory blood pressure monitoring, and a series of biomarkers for cardiovascular and bone mineral disease.<p></p>
Conclusions: These data will prove valuable by characterizing the direction of causality between cardiovascular and renal disease. This should help inform whether targeting reduced GFR alongside more traditional cardiovascular risk factors is warranted. In addition, this study will contribute important safety data on living kidney donors by providing a longitudinal assessment of well-validated surrogate markers of cardiovascular disease, namely, blood pressure and arterial stiffness. If any adverse effects are detected, these may be potentially reversed with the early introduction of targeted therapy. This should ensure that kidney donors do not come to long-term harm and thereby preserve the ongoing expansion of the living donor transplant program.<p></p>
Endothelial nitric oxide synthase single nucleotide polymorphism and left ventricular function in early chronic kidney disease
Chronic kidney disease (CKD) is associated with accelerated cardiovascular disease and heart failure. Endothelial nitric oxide synthase (eNOS) Glu298Asp single nucleotide polymorphism (SNP) genotype has been associated with a worse phenotype amongst patients with established heart failure and in patients with progression of their renal disease. The association of a cardiac functional difference in non-dialysis CKD patients with no known previous heart failure, and eNOS gene variant is investigated. Methods 140 non-dialysis CKD patients, who had cardiac magnetic resonance (CMR) imaging and tissue doppler echocardiography as part of two clinical trials, were genotyped for eNOS Glu298Asp SNP retrospectively. Results The median estimated glomerular filtration rate (eGFR) was 50mls/min and left ventricular ejection fraction (LVEF) was 74 with no overt diastolic dysfunction in this cohort. There were significant differences in LVEF across eNOS genotypes with GG genotype being associated with a worse LVEF compared to other genotypes (LVEF: GG 71, TG 76, TT 73, p = 0.006). After multivariate analysis, (adjusting for age, eGFR, baseline mean arterial pressure, contemporary CMR heart rate, total cholesterol, high sensitive C-reactive protein, body mass index and gender) GG genotype was associated with a worse LVEF, and increased LV end-diastolic and systolic index (p = 0.004, 0.049 and 0.009 respectively). Conclusions eNOS Glu298Asp rs1799983 polymorphism in CKD patients is associated with relevant sub-clinical cardiac remodelling as detected by CMR. This gene variant may therefore represent an important genetic biomarker, and possibly highlight pathways for intervention, in these patients who are at particular risk of worsening cardiac disease as their renal dysfunction progresses. © 2015 Chand et al
Association of treatment satisfaction and psychopathological sub-syndromes among involuntary patients with psychotic disorders
Publisher's version: http://www.springerlink.com/content/rx24036274667t10
Fourth Workshop on Sustainable Software for Science: Practice and Experiences (WSSSPE4)
This report records and discusses the Fourth Workshop on Sustainable Software
for Science: Practice and Experiences (WSSSPE4). The report includes a
description of the keynote presentation of the workshop, the mission and vision
statements that were drafted at the workshop and finalized shortly after it, a
set of idea papers, position papers, experience papers, demos, and lightning
talks, and a panel discussion. The main part of the report covers the set of
working groups that formed during the meeting, and for each, discusses the
participants, the objective and goal, and how the objective can be reached,
along with contact information for readers who may want to join the group.
Finally, we present results from a survey of the workshop attendees
Blood Pressure and Vascular Response to Maximal Graded Exercise Tests in Young Men with Masked Hypertension
Masked hypertension is a risk factor for cardiovascular diseases. Individuals with masked hypertension have elevated out-of-office blood pressure (BP), but usually have normal office BP, making masked hypertension less likely to be diagnosed. PURPOSE: The aim of this study was to determine whether in-laboratory measurements of BP and vascular function in response to exercise can serve as indicators of masked hypertension in young adults. METHODS: Thirty-three young men with normal office BP (\u3c130/80 mmHg), free of smoking and clinical diseases, were included in this study. All participants underwent 24-hr ambulatory BP monitoring for determination of BP classification. Masked hypertension is defined as 24-hr average BP ≥125/75 mmHg, daytime BP ≥130/80 mmHg, or nighttime BP ≥110/65 mmHg. All participants received a comprehensive in-laboratory BP and vascular assessment in the supine position after a 10-min rest and after a maximal graded exercise test on a cycle ergometer. The assessment includes brachial and central BP, arterial stiffness measured as carotid to femoral pulse wave velocity, wave reflection measured as augmentation index and reflection magnitude, and endothelial function measured as flow-mediated dilation. RESULTS: Compared to normotensive participants (CON; n=17), those with masked hypertension (MH; n=16) had a higher level of 24-hr, daytime, and nighttime systolic BP (P≤0.005), but similar office BP (P≥0.5). Prior to exercise, no differences between groups were found in all in-laboratory BP and vascular function measurements (P≥0.2). While brachial BP and vascular function responses to exercise were not different between groups (P≥0.2 for group by time interaction effects), MH had an overall higher central systolic BP from resting to 30 min following the exercise than CON (P=0.047 for group effect). CONCLUSION: Our study demonstrates that young men with masked hypertension had a similar in-laboratory brachial BP and vascular function at rest and in response to maximal exercise tests as normotensive young men. These findings suggest that these in-laboratory measurements are unable to detect pathophysiological changes associated with masked hypertension in young men. On the other hand, central BP response to exercise was elevated in young men with masked hypertension, suggesting this measure may serve as an early indicator of masked hypertension in men
Sex differences in basal hypothalamic anorectic and orexigenic gene expression and the effect of quantitative and qualitative food restriction
Abstract Background Research into energy balance and growth has infrequently considered genetic sex, yet there is sexual dimorphism for growth across the animal kingdom. We test the hypothesis that in the chicken, there is a sex difference in arcuate nucleus neuropeptide gene expression, since previous research indicates hypothalamic AGRP expression is correlated with growth potential and that males grow faster than females. Because growth has been heavily selected in some chicken lines, food restriction is necessary to improve reproductive performance and welfare, but this increases hunger. Dietary dilution has been proposed to ameliorate this undesirable effect. We aimed to distinguish the effects of gut fullness from nutritional feedback on hypothalamic gene expression and its interaction with sex. Methods Twelve-week-old male and female fast-growing chickens were either released from restriction and fed ad libitum or a restricted diet plus 15% w/w ispaghula husk, a non-nutritive bulking agent, for 2 days. A control group remained on quantitative restriction. Hypothalamic arcuate nucleus neuropeptides were measured using real-time PCR. To confirm observed sex differences, the experiment was repeated using only ad libitum and restricted fed fast-growing chickens and in a genetically distinct breed of ad libitum fed male and female chickens. Linear mixed models (Genstat 18) were used for statistical analysis with transformation where appropriate. Results There were pronounced sex differences: expression of the orexigenic genes AGRP (P < 0.001) and NPY (P < 0.002) was higher in males of the fast-growing strain. In genetically distinct chickens, males had higher AGRP mRNA (P = 0.002) expression than females, suggesting sex difference was not restricted to a fast-growing strain. AGRP (P < 0.001) expression was significantly decreased in ad libitum fed birds but was high and indistinguishable between birds on a quantitative versus qualitative restricted diet. Inversely, gene expression of the anorectic genes POMC and CART was significantly higher in ad libitum fed birds but no consistent sex differences were observed. Conclusion Expression of orexigenic peptides in the avian hypothalamus are significantly different between sexes. This could be useful starting point of investigating further if AGRP is an indicator of growth potential. Results also demonstrate that gut fill alone does not reduce orexigenic gene expression
Epidemiology and Treatment Guidelines of Negative Symptoms in Schizo-phrenia in Central and Eastern Europe: A Literature Review
AIM: To gather and review data describing the epidemiology of schizophrenia and clinical guidelines for schizophrenia therapy in seven Central and Eastern European countries, with a focus on negative symptoms. Methods : A literature search was conducted which included publications from 1995 to 2012 that were indexed in key databases. Results : Reports of mean annual incidence of schizophrenia varied greatly, from 0.04 to 0.58 per 1,000 population. Lifetime prevalence varied from 0.4% to 1.4%. One study reported that at least one negative symptom was present in 57.6% of patients with schizophrenia and in 50-90% of individuals experiencing their first episode of schizophrenia. Primary negative symptoms were observed in 10-30% of patients. Mortality in patients with schizophrenia was greater than in the general population, with a standardized mortality ratio of 2.58-4.30. Reasons for higher risk of mortality in the schizophrenia population included increased suicide risk, effect of schizophrenia on lifestyle and environment, and presence of comorbidities. Clinical guidelines overall supported the use of second-generation antipsychotics in managing negative symptoms of schizophrenia, although improved therapeutic approaches are needed. Conclusion : Schizophrenia is one of the most common mental illnesses and poses a considerable burden on patients and healthcare resources alike. Negative symptoms are present in many patients and there is an unmet need to improve treatment offerings for negative symptoms beyond the use of second-generation antipsychotics and overall patient outcomes
Socially learned attitude change is not reduced in medicated patients with schizophrenia
Schizophrenia is often associated with distinctive or odd social behaviours. Previous work suggests this could be due to a general reduction in conformity; however, this work only assessed the tendency to publicly agree with others, which may involve a number of different mechanisms. In this study, we specifically investigated whether patients display a reduced tendency to adopt other people’s opinions (socially learned attitude change). We administered a computerized conformity task, assumed to rely on reinforcement learning circuits, to 32 patients with schizophrenia or schizo-affective disorder and 39 matched controls. Each participant rated 153 faces for trustworthiness. After each rating, they were immediately shown the opinion of a group. After approximately 1 hour, participants were unexpectedly asked to rate all the faces again. We compared the degree of attitude change towards group opinion in patients and controls. Patients presented equal or more social influence on attitudes than controls. This effect may have been medication induced, as increased conformity was seen with higher antipsychotic dose. The results suggest that there is not a general decline in conformity in medicated patients with schizophrenia and that previous findings of reduced conformity are likely related to mechanisms other than reinforcement based social influence on attitudes
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