179 research outputs found
Numerical Flow Analysis of an Axial Flow Pump
This paper describes the detailed study of fluid flows in an axial pump that includes impeller and guide vanes. And the comparisons of flow simulations of the axial pump impeller with guide vanes and without guide vanes are carried out in this paper. In addition to this, the effect of number of guide blades on flow behaviours is analysed numerically. The computational results are performed by using one of CFD commercial software, Solidworks Flow Simulation. The input design data of the model pump are the flow rate of 0.2m3, head of 3m and the rotational speed of 1160 rpm. The outer and inner diameter of impeller is 0.3m and 0.15m respectively. . And the impeller with four blades is used in this paper. The guide blade number is varied to 5,7,9nbsp with the same input data and other geometric parameters keep constant. In this study, the nature of velocities and pressures in an axial flow pump is analysed. The comparisons are averaged flow velocities, static pressure rise, dynamic pressure and total pressure.nbs
Risk Prediction Models for Colorectal Cancer: A Systematic Review.
Colorectal cancer is the second leading cause of cancer-related death in Europe and the United States. Survival is strongly related to stage at diagnosis and population-based screening reduces colorectal cancer incidence and mortality. Stratifying the population by risk offers the potential to improve the efficiency of screening. In this systematic review we searched Medline, EMBASE, and the Cochrane Library for primary research studies reporting or validating models to predict future risk of primary colorectal cancer for asymptomatic individuals. A total of 12,808 papers were identified from the literature search and nine through citation searching. Fifty-two risk models were included. Where reported (n = 37), half the models had acceptable-to-good discrimination (the area under the receiver operating characteristic curve, AUROC >0.7) in the derivation sample. Calibration was less commonly assessed (n = 21), but overall acceptable. In external validation studies, 10 models showed acceptable discrimination (AUROC 0.71-0.78). These include two with only three variables (age, gender, and BMI; age, gender, and family history of colorectal cancer). A small number of prediction models developed from case-control studies of genetic biomarkers also show some promise but require further external validation using population-based samples. Further research should focus on the feasibility and impact of incorporating such models into stratified screening programmes.J Usher-Smith is funded by a National Institute of Health Research (NIHR) Clinical Lectureship and F Walter by an NIHR Clinician Scientist award. J Emery is funded by an Australian National Health and Medical Research Council (NHMRC) Practitioner Fellowship. A Wong has an NHMRC Early Career Fellowship. The views expressed in this publication are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health.This is the author accepted manuscript. The final version is available from American Association for Cancer Research via http://dx.doi.org/10.1158/1940-6207.CAPR-15-027
Should the grading of colorectal adenocarcinoma include microsatellite instability status?
Adenocarcinomas of the colon and rectum are graded using a 2-tiered system into histologic low-grade and high-grade tumors based on the proportion of gland formation. The current grading system does not apply to subtypes of carcinomas associated with a high frequency of microsatellite instability (MSI), such as mucinous and medullary carcinomas. We investigated the combined effect of histologic grade and MSI status on survival for 738 patients with colorectal carcinoma (48% female; mean age at diagnosis 68.2 years). The proportion of high-grade adenocarcinoma was 18%. MSI was observed in 59 adenocarcinomas (9%), with higher frequency in high-grade tumors compared with low-grade tumors (20% versus 6%; P < .001). Using Cox regression models, adjusting for sex and age at diagnosis and stratifying by the American Joint Committee on Cancer stage, microsatellite stable (MSS) high-grade tumors were associated with increased hazard of all-cause and colorectal cancer specific mortality: hazard ratio 2.09 (95% confidence interval [CI], 1.58-2.77) and 2.54 (95% CI, 1.86-3.47), respectively, both P < .001. A new grading system separating adenocarcinoma into low grade (all histologic low grade and MSI high grade) and high grade (MSS histologic high grade) gave a lower Akaike information criterion value when compared with the current grading system and thus represented a better model fit to stratify patients according to survival. We found that patients with a high-grade adenocarcinoma had significantly shorter survival than patients with low-grade adenocarcinoma only if the tumor was MSS, suggesting that the grading of colorectal adenocarcinoma with high-grade histologic features should be made according to the MSI status of the tumor. (C) 2014 Elsevier Inc. All rights reserved
Associations of Height With the Risks of Colorectal and Endometrial Cancer in Persons With Lynch Syndrome
People with Lynch syndrome (LS), who carry a pathogenic mutation in a DNA mismatch repair gene, have increased risks of colorectal cancer (CRC) and endometrial cancer (EC). A high reported variability in cancer risk suggests the existence of factors that modify cancer risk for persons with LS. We aimed to investigate the associations between height and CRC and EC risk for persons with LS using data from 2 large studies. Information on 1,115 men and 1,553 women with LS from the Colon Cancer Family Registry (1998-2007) and the GEOLynch Cohort Study (2006-2017) was harmonized. We used weighted Cox proportional hazards regression models with age on the time axis to estimate adjusted hazard ratios and 95% confidence intervals for each 5-cm increment in self-reported height. CRC was diagnosed in 947 persons during 65,369 person-years of observation, and 171 women were diagnosed with EC during 39,227 person-years. Height was not associated with CRC for either men (per 5-cm increment, hazard ratio (HR) = 1.00, 95% confidence interval (CI): 0.91, 1.11) or women (per 5-cm increment, HR = 1.01, 95% CI: 0.92, 1.11), nor was height associated with EC (per 5-cm increment, HR = 1.08, 95% CI: 0.94, 1.24). Hence, we observed no evidence for an association of height with either CRC or EC among persons with LS.</p
Agricultural and food systems in the Mekong region: Drivers of transformation and pathways of change
Agricultural and food systems in the Mekong Region are undergoing transformations because of increasing engagement in international trade, alongside economic growth, dietary change and urbanisation. Food systems approaches are often used to understand these kinds of transformation processes, with particular strengths in linking social, economic and environmental dimensions of food at multiple scales. We argue that while the food systems approach strives to provide a comprehensive understanding of food production, consumption and environmental drivers, it is less well equipped to shed light on the role of actors, knowledge and power in transformation processes and on the divergent impacts and outcomes of these processes for different actors. We suggest that an approach that uses food systems as heuristics but complements it with attention to actors, knowledge and power improves our understanding of transformations such as those underway in the Mekong Region. The key transformations in the region include the emergence of regional food markets and vertically integrated supply chains that control increasing share of the market, increase in contract farming particularly in the peripheries of the region, replacement of crops cultivated for human consumption with corn grown for animal feed. These transformations are increasingly marginalising small-scale farmers, while at the same time, many other farmers increasingly pursue non-agricultural livelihoods. Food consumption is also changing, with integrated supply chains controlling substantial part of the mass market. Our analysis highlights that theoretical innovations grounded in political economy, agrarian change, development studies and rural livelihoods can help to increase theoretical depth of inquiries to accommodate the increasingly global dimensions of food. As a result, we map out a future research agenda to unpack the dynamic food system interactions and to unveil the social, economic and environmental impacts of these rapid transformations. We identify policy and managerial implications coupled with sustainable pathways for change
Germline mutations in PMS2 and MLH1 in individuals with solitary loss of PMS2 expression in colorectal carcinomas from the Colon Cancer Family Registry Cohort
Immunohistochemistry for DNA mismatch repair proteins is used to screen for Lynch syndrome in individuals with colorectal carcinoma (CRC). Although solitary loss of PMS2 expression is indicative of carrying a germline mutation in PMS2, previous studies reported MLH1 mutation in some cases. We determined the prevalence of MLH1 germline mutations in a large cohort of individuals with a CRC demonstrating solitary loss of PMS2 expression
Surveillance to achieve malaria elimination in eastern Myanmar: a 7-year observational study
Background The collection and utilization of surveillance data is essential in monitoring progress towards achieving malaria elimination, in the timely response to increases in malaria case numbers and in the assessment of programme functioning. This paper describes the surveillance activities used by the malaria elimination task force (METF) programme which operates in eastern Myanmar, and provides an analysis of data collected from weekly surveillance, case investigations, and monitoring and evaluation of programme performance. Methods This retrospective analysis was conducted using data collected from a network of 1250 malaria posts operational between 2014 and 2021. To investigate changes in data completeness, malaria post performance, malaria case numbers, and the demographic details of malaria cases, summary statistics were used to compare data collected over space and time. Results In the first 3 years of the METF programme, improvements in data transmission routes resulted in a 18.9% reduction in late reporting, allowing for near real-time analysis of data collected at the malaria posts. In 2020, travel restrictions were in place across Karen State in response to COVID-19, and from February 2021 the military coup in Myanmar resulted in widescale population displacement. However, over that period there has been no decline in malaria post attendance, and the majority of consultations continue to occur within 48 h of fever onset. Case investigations found that 43.8% of cases travelled away from their resident village in the 3 weeks prior to diagnosis and 36.3% reported never using a bed net whilst sleeping in their resident village, which increased to 72.2% when sleeping away from their resident village. Malaria post assessments performed in 82.3% of the METF malaria posts found malaria posts generally performed to a high standard. Conclusions Surveillance data collected by the METF programme demonstrate that despite significant changes in the context in which the programme operates, malaria posts have remained accessible and continue to provide early diagnosis and treatment contributing to an 89.3% decrease in Plasmodium falciparum incidence between 2014 and 2021
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