Investigation of Performance and Cavitation Treatment in a Kaplan Hydro Turbine

Cavitation is a phenomenon that occurs in various turbomachinery applications causing drawbacks on the. Some of these downsides are damaging the components of the system, generating noise and vibration, and loss of the turbine efficiency over time. Thus, it is imperative to address issue of cavitation to increase the life span of the equipment in addition to improve the system performance. This thesis introduces a method used to mitigate the cavitation phenomenon in a 3-inch Kaplan hydro turbine via injecting air at the leading edge of the rotor blades. The study is based on modeling the turbine using Computational Fluid Dynamics (CFD) software as well as carrying out experimental tests. The simulations were conducted at different air injection pressures over a spectrum of rotational speeds using Large Eddy Simulation (LES) for turbulence and volume of fluid for multiphase interactions: water, vapor water and air. The cavitation behavior was observed first without aeration, then followed by air injection simulations to investigate the effect of aeration. Each case was simulated for 12 cycles at rotational speeds of 1000, 2000, 3000, 4000, and 5000 rpm. The Vapor Volume Fraction (VVF) and the output mechanical power were monitored throughout the simulations. The data acquired from the simulations were compared to the experimental results for verifications. It was observed that the cavitation was mitigated in both the computer simulations and the experiment testing reaching up to 49.7% as an average reduction, while the output power was reduced by 6.6%

Assessment of correlates of hand hygiene compliance among final year medical students: a cross-sectional study in the Netherlands

OBJECTIVES: To identify the factors that influence the hand hygiene compliance of final year medical students, using a theoretical behavioural framework. DESIGN: Cross-sectional survey assessing self-reported compliance and its behavioural correlates. SETTING: Internships of medical students in the Netherlands. PARTICIPANTS: 322 medical students of the Erasmus Medical Center were recruited over a period of 12 months during the Public Health internship, which is the final compulsory internship after an 18-month rotation schedule in all major specialities. PRIMARY AND SECONDARY OUTCOME MEASURES: Behavioural factors influencing compliance to hand hygiene guidelines were measured by means of a questionnaire based on the Theory of Planned Behaviour and Social Ecological Models. Multiple lin

Cost-effectiveness of postural exercise therapy versus physiotherapy in computer screen-workers with early non-specific work-related upper limb disorders (WRULD); a randomized controlled trial

<p>Abstract</p> <p>Background</p> <p>Exercise therapies generate substantial costs in computer workers with non-specific work-related upper limb disorders (WRULD).</p> <p>Aims</p> <p>To study if postural exercise therapy is cost-effective compared to regular physiotherapy in screen-workers with early complaints, both from health care and societal perspective.</p> <p>Methods</p> <p>Prospective randomized trial including cost-effectiveness analysis; one year follow-up. Participants: Eighty-eight screen-workers with early non-specific WRULD; six drop-outs. Interventions: A ten week postural exercise program versus regular physiotherapy. Outcome measures: Effectiveness measures: Pain: visual analogous scale (VAS), self-perceived WRULD (yes/no). Functional outcome: Disabilities of Arm, Shoulder and Hand- Dutch Language Version (DASH-DLV). Quality of life outcome: EQ-5D.</p> <p>Economic measures: health care costs including patient and family costs and productivity costs resulting in societal costs. Cost-effectiveness measures: health care costs and societal costs related to the effectiveness measures. Outcome measures were assessed at baseline; three, six and twelve months after baseline.</p> <p>Results</p> <p>At baseline both groups were comparable for baseline characteristics except scores on the Pain Catastrophizing Scale and comparable for costs. No significant differences between the groups concerning effectiveness at one year follow-up were found. Effectiveness scores slightly improved over time. After one year 55% of participants were free of complaints. After one year the postural exercise group had higher mean total health care costs, but lower productivity costs compared to the physiotherapy group. Mean societal costs after one year (therefore) were in favor of postural exercise therapy [- €622; 95% CI -2087; +590)]. After one year, only self- perceived WRULD seemed to result in acceptable cost-effectiveness of the postural exercise strategy over physiotherapy; however the probability of acceptable cost-effectiveness did not exceed 60%.</p> <p>Considering societal costs related to QALYs, postural exercise therapy had a probability of over 80% to be cost-effective over a wide range of cost-effectiveness ceiling ratios; however based on a marginal QALY-difference of 0.1 over a 12 month time frame.</p> <p>Conclusion</p> <p>Although our trial failed to find significant differences in VAS, QALYs and ICERs based on VAS and QALYs at one-year follow-up, CEACs suggest that postural exercise therapy according to Mensendieck/Cesar has a higher probability of being cost-effective compared to regular physiotherapy; however further research is required.</p> <p>Trial registration</p> <p>ISRCTN 15872455</p

The effect of NOTCH3 pathogenic variant position on CADASIL disease severity: NOTCH3 EGFr 1&#8211;6 pathogenic variant are associated with a more severe phenotype and lower survival compared with EGFr 7&#8211;34 pathogenic variant

Purpose: CADASIL is a small-vessel disease caused by a cysteine-altering pathogenic variant in one of the 34 epidermal growth factor-like repeat (EGFr) domains of the NOTCH3 protein. We recently found that pathogenic variant in EGFr domains 7\u201334 have an unexpectedly high frequency in the general population (1:300). We hypothesized that EGFr 7\u201334 pathogenic variant more frequently cause a much milder phenotype, thereby explaining an important part of CADASIL disease variability. Methods: Age at first stroke, survival and white matter hyperintensity volume were compared between 664 CADASIL patients with either a NOTCH3 EGFr 1\u20136 pathogenic variant or an EGFr 7\u201334 pathogenic variant. The frequencies of NOTCH3 EGFr 1\u20136 and EGFr 7\u201334 pathogenic variant were compared between individuals in the genome Aggregation Database and CADASIL patients. Results: CADASIL patients with an EGFr 1\u20136 pathogenic variant have a 12-year earlier onset of stroke than those with an EGFr 7\u201334 pathogenic variant, lower survival, and higher white matter hyperintensity volumes. Among diagnosed CADASIL patients, 70% have an EGFr 1\u20136 pathogenic variant, whereas EGFr 7\u201334 pathogenic variant strongly predominate in the population. Conclusion: NOTCH3 pathogenic variant position is the most important determinant of CADASIL disease severity, with EGFr 7\u201334 pathogenic variant predisposing to a later onset of stroke and longer survival

The spatial relationship between the MRI lesion and intraoperative electrocorticography in focal epilepsy surgery.

MRI and intraoperative electrocorticography are often used in tandem to delineate epileptogenic tissue in resective surgery for focal epilepsy. Both the resection of the MRI lesion and tissue with high rates of electrographic discharges on electrocorticography, e.g. spikes and high-frequency oscillations (80-500 Hz), lead to a better surgical outcome. How MRI and electrographic markers are related, however, is currently unknown. The aim of this study was to find the spatial relationship between MRI lesions and spikes/high-frequency oscillations. We retrospectively included 33 paediatric and adult patients with lesional neocortical epilepsy who underwent electrocorticography-tailored surgery (14 females, median age = 13.4 years, range = 0.6-47.0 years). Mesiotemporal lesions were excluded. We used univariable linear regression to find correlations between pre-resection spike/high-frequency oscillation rates on an electrode and its distance to the MRI lesion. We tested straight lines to the centre and the edge of the MRI lesion, and the distance along the cortical surface to determine which of these distances best reflects the occurrence of spikes/high-frequency oscillations. We conducted a moderator analysis to investigate the influence of the underlying pathology type and lesion volume on our results. We found spike and high-frequency oscillation rates to be spatially linked to the edge of the MRI lesion. The underlying pathology type influenced the spatial relationship between spike/high-frequency oscillation rates and the MRI lesion (P spikes < 0.0001, P ripples < 0.0001), while the lesion volume did not (P spikes = 0.64, P ripples = 0.89). A higher spike rate was associated with a shorter distance to the edge of the lesion for cavernomas [F(1,64) = -1.37, P < 0.0001, η 2 = 0.22], focal cortical dysplasias [F(1,570) = -0.25, P < 0.0001, η 2 = 0.05] and pleomorphic xanthoastrocytomas [F(1,66) = -0.18, P = 0.01, η 2 = 0.09]. In focal cortical dysplasias, a higher ripple rate was associated with a shorter distance [F(1,570) = -0.35, P < 0.0001, η 2 = 0.05]. Conversely, low-grade gliomas showed a positive correlation; the further an electrode was away from the lesion, the higher the rate of spikes [F(1,75) = 0.65, P < 0.0001, η 2 = 0.37] and ripples [F(1,75) = 2.67, P < 0.0001, η 2 = 0.22]. Pathophysiological processes specific to certain pathology types determine the spatial relationship between the MRI lesion and electrocorticography results. In our analyses, non-tumourous lesions (focal cortical dysplasias and cavernomas) seemed to intrinsically generate spikes and high-frequency oscillations, particularly at the border of the lesion. This advocates for a resection of this tissue. Low-grade gliomas caused epileptogenicity in the peritumoural tissue. Whether a resection of this tissue leads to a better outcome is unclear. Our results suggest that the underlying pathology type should be considered when intraoperative electrocorticography is interpreted

Risk factors and outcomes for postoperative delirium after major surgery in elderly patients

Background: Early identification of patients at risk for delirium is important, since adequate well timed interventions could prevent occurrence of delirium and related detrimental outcomes. The aim of this study is to evaluate prognostic factors for delirium, including factors describing frailty, in elderly patients undergoing major surgery. Methods: We included patients of 65 years and older, who underwent elective surgery from March 2013 to November 2014. Patients had surgery for Abdominal Aortic Aneurysm (AAA) or colorectal cancer. Delirium was scored prospectively using the Delirium Observation Screening Scale. Pre- and peri-operative predictors of delirium were analyzed using regression analysis. Outcomes after delirium included adverse events, length of hospital stay, discharge destination and mortality. Results: We included 232 patients. 51 (22%) underwent surgery for AAA and 181 (78%) for colorectal cancer. Postoperative delirium occurred in 35 patients (15%). Predictors of postoperative delirium included: delirium in medical history (Odds Ratio 12 [95% Confidence Interval 2.7-50]), advancing age (Odds Ratio 2.0 [95% Confidence Interval 1.1-3.8]) per 10 years, and ASA-score ≥3 (Odds Ratio 2.6 [95% Confidence Interval 1.1-5.9]). Occurrence of delirium was related to an increase in adverse events, length of hospital stay and mortality. Conclusion: Postoperative delirium is a frequent complication after major surgery in elderly patients and is related to an increase in adverse events, length of hospital stay, and mortality. A delirium in the medical history, advanced age, and ASA

The importance of multidisciplinary teamwork and team climate for relational coordination among teams delivering care to older patients

Aim: To identify predictors of relational coordination among professionals delivering care to older patients. Background: Relational coordination is known to enhance quality of care in hospitals. The underlying mechanisms, however, remain poorly understood. Design: This cross-sectional study was part of a larger evaluation study examining the opportunity to prevent loss of function in older patients due to hospitalization in the Netherlands. Methods: This study was performed in spring 2010 among team members delivering care to older hospitalized patients (192 respondents; 44% response rate) in one hospital. Relational coordination was measured by the Relational Coordination survey; team climate by the Team Climate Inventory and questions were asked about participation in multidisciplinary team meetings and disciplines represented in these meetings. To account for the hierarchical structure, a multilevel analysis was performed. Results: Correlation analysis revealed a positive relationship among being female, being a nurse and relational coordination; medical specialists showed a negative relationship. The number of disciplines represented during multidisciplinary team meetings and team climate were positively related with relational coordination. The multilevel analysis showed a positive relationship between the number of disciplines represented during multidisciplinary team meetings and team climate with relational coordination. Conclusions: The enhancement of team climate and attendance of diverse professionals during multidisciplinary team meetings are expected to improve relational coordination. Furthermore, this study underscores the importance of enhancing relational coordination between medical specialists and other professionals

Eighteen-year disease progression and survival in CADASIL

Neuro Imaging Researc

Inverse Association between trans Isomeric and Long-Chain Polyunsaturated Fatty Acids in Pregnant Women and Their Newborns: Data from Three European Countries

Background: trans unsaturated fatty acids are thought to interfere with essential fatty acid metabolism. To extend our knowledge of this phenomenon, we investigated the relationship between trans isomeric and long-chain polyunsaturated fatty acids (LCPUFA) in mothers during pregnancy and in their infants at birth. Methods: Fatty acid composition of erythrocyte phosphatidylcholine (PC) and phosphatidylethanolamine (PE) was determined in Spanish (n = 120), German (n = 78) and Hungarian (n = 43) women at the 20th and 30th week of gestation, at delivery and in their newborns. Results: At the 20th week of gestation, the sum of trans fatty acids in PE was significantly (p < 0.01) lower in Hungarian [0.73 (0.51), % wt/wt, median (IQR)] than in Spanish [1.42 (1.36)] and German [1.30 (1.21)] women. Docosahexaenoic acid (DHA) values in PE were significantly (p < 0.01) higher in Hungarian {[}5.65 (2.09)] than in Spanish [4.37 (2.60)] or German [4.39 (3.3.2)] women. The sum of trans fatty acids significantly inversely correlated to DHA in PCs in Spanish (r = -0.37, p < 0.001), German (n = -0.77, p < 0.001) and Hungarian (r = -0.35, p < 0.05) women, and in PEs in Spanish (r = -0.67, p < 0.001) and German (r = -0.71, p < 0.001), but not in Hungarian (r = -0.02) women. Significant inverse correlations were seen between trans fatty acids and DHA in PEs at the 30th week of gestation (n = 241, r = -0.52, p < 0.001), at delivery (n = 241, r = -0.40, p < 0.001) and in cord lipids (n = 218, r = -0.28, p < 0.001). Conclusion: Because humans cannot synthesize trans isomeric fatty acids, the data obtained in the present study support the concept that high maternal trans isomeric fatty acid intake may interfere with the availability of LCPUFA both for the mother and the fetus. Copyright (C) 2011 S. Karger AG, Base

Ethnic Differences in Cardiometabolic Risk Profile at Age 5-6 Years: The ABCD Study

Background: To examine ethnic differences in cardiometabolic risk profile in early age, and explore whether such differences can be explained by differences in body mass index (BMI) or waist circumference (WC). Method: Anthropometric measurements, blood pressure and (in a subsample) fasting blood were collected during a health check of 2,509 children aged 5-6 years. Four ethnic groups were distinguished: Dutch (n = 2,008; blood n = 1,300), African descent (n = 199; blood n = 105), Turkish (n = 108; blood n = 57) and Moroccan (n = 194; blood n = 94). Ethnic differences in diastolic and systolic blood pressure (DBP/SBP), fasting glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL) and triglyceride levels were determined and the explanatory role of BMI and WC was examined with regression analysis. Results: After adjustment for confounders, African descent children showed higher DBP (beta 2.22 mmHg; 95% CI: 1.09-3.36) and HDL levels (beta:0.09 mmol/l; 95% CI: 0.03-0.16) compared to Dutch children (reference group). Turkish children showed higher SBP (beta:1.89 mmHg; 95% CI: 0.25-3.54), DBP (beta:2.62 mmHg; 95% CI: 1.11-4.13), glucose (beta:0.12 mmol/L; 95% CI: 0.00-0.25) and triglyceride levels (beta:0.13 mmol/L; 95% CI: 0.02-0.25). Higher BMI values were found in all non-Dutch groups (differences ranged from 0.53-1.03 kg/m(2)) and higher WC in Turkish (beta:1.68 cm; 95% CI: 0.99-2.38) and Moroccan (beta:1.65 cm; 95% CI:1.11-2.19) children. BMI and WC partly explained the higher SBP/DBP and triglyceride levels in Turkish children. Conclusion: Ethnic differences in cardiometabolic profile exist early in life and are partly explained by differences in BMI and WC. African children showed favourable HDL levels and Turkish children the most unfavourable overall profile, whereas their Moroccan peers have less increased cardiometabolic risk in spite of their high BMI and W