Reliability based robust design optimization based on sensitivity and elasticity factors analysis

In this paper, a Reliability Based Robust Design Optimization (RBRDO) based on sensitivity and elasticity factors analysis is presented. In the first step, a reliability assessment is performed using the First-and Second Order Reliability Method (FORM)/ (SORM), and Monte Carlo Simulation. Furthermore, FORM method is used for reliability elasticity factors assessment, which can be carried out to determine the most influential parameters, these factors can be help to reduce the size of design variables vector in RBRDO process. The main objective of the RBRDO is to improve both reliability and design of a cylindrical gear pair under uncertainties. This approach is achieved by integration of two objectives which minimize the variance and mean values of performance function. To solve this problem a decoupled approach of Sequential Optimization and Reliability Assessment (SORA) method is implemented. The results obtained shown that a desired reliability with a robust design is progressively achieved

Multiscale Quantitative Imaging of Human Femoral Heads Using X-ray Microtomography

PhDClinical diagnostic tools provide limited information on the underlying structural and mechanical properties of bone-tissue affected by degenerative and bone metabolic diseases. In-vivo bone failure studies provide limited information due to constraints such as X-ray dosage, cost and various other practicalities. In-vitro studies are thus required to enhance understanding of this phenomenon. The aims of this study were to use quantitative high-definition X-ray Micro-Tomography (XMT) to assess factors contributing to pathological and non-pathological bone failure and repair in relation to the mechanics of whole human femoral heads. XMT images of one normal and six pathological femoral heads were collected at 26 – 8.8 μm voxel resolution and evaluated to determine structural features; bone mineral concentration (BMC); and using image analysis, identify microcallus formations. In addition, in-vitro compression tests were carried out on specimens taken from regions with different anatomical loading. Bone quality was then related to the anatomical loading and BMC. Results from non-pathological tissue where used to establish a baseline for measurements of structural features. Microcallus formations where identified and used as markers to map the occurrence of bone damage. In osteoarthritic (OA) heads, the damage was found to be concentrated in localised clusters. Conversely, in the osteoporotic head damage was distributed homogeneously throughout the entire specimen. No significant difference in the BMC was observed, however there was a iii significant difference in the bone quality values between the non-pathological and pathological heads, and also between the pathologies. In-vitro mechanical testing revealed a difference in the mechanical properties of OA trabecular bone in relation to bone quality measurements but the samples exhibited no significant correlation to anatomical loading. X-ray Ultra Microscopy (XuM) at 200nm and 775nm voxel resolution was used to investigate the nano-morphology of individual trabeculae. The XuM images showed differences in bone structure and fewer osteocyte lacunae present close to fracture site. XuM also identified micro-cracks within trabeculae that were encased by microcallus formations. The application of novel quantitative high definition X-ray imaging to clinically relevant tissue at multiple length scales has provided new metrological data on the distribution of damage within pathological tissue. Insight into the vulnerability of diseased tissue to damage could ultimately lead to improved diagnosis from clinical radiographs

Reliability based robust design optimization based on sensitivity and elasticity factors analysis

In this paper, a Reliability Based Robust Design Optimization (RBRDO) based on sensitivity and elasticity factors analysis is presented. In the first step, a reliability assessment is performed using the First-and Second Order Reliability Method (FORM)/ (SORM), and Monte Carlo Simulation. Furthermore, FORM method is used for reliability elasticity factors assessment, which can be carried out to determine the most influential parameters, these factors can be help to reduce the size of design variables vector in RBRDO process. The main objective of the RBRDO is to improve both reliability and design of a cylindrical gear pair under uncertainties. This approach is achieved by integration of two objectives which minimize the variance and mean values of performance function. To solve this problem a decoupled approach of Sequential Optimization and Reliability Assessment (SORA) method is implemented. The results obtained shown that a desired reliability with a robust design is progressively achieved

Drivers of Entrepreneurship: Linking With Economic Growth and Employment Generation (A Panel Data Analysis)

The need for entrepreneurs for economic development has always been crucial in history because they are the leaders who invent innovative ideas that give spark to economic activities. They are responsible for the combination of factors of production by capital formation, creating employment opportunities, wealth distribution that facilitates development and growth. A well explained definition of entrepreneurship in the words of Wennekers and Thurik (1999) that successfully makes the functional roles of entrepreneurs is: “…the manifest ability and willingness of individuals, on their own, in teams within and outside existing organisations, to perceive and create new economic opportunities (new products, new production methods, new organisational schemes and new product-market combinations) and to introduce their ideas in the market, in the face of uncertainty and other obstacles, by making decisions on location, form and the use of resources and institutions.” (46–47) High and sustained economic growth is the fundamental objective of every developed or developing country’s governmental policy. Economic growth is a long term expansion of the productive potential of the economy. It generates employment in the economy and raises the living standards of the nation. Economic growth promotes business activities in private sector, increases company profits and enhances investor confidence

THE EFFECT OF LEARNING STYLE, HOME ENVIRONMENT AND SCHOOL ENVIRONMENT ON ACADEMIC ACHIEVEMENT OF NINTH STANDARD STUDENTS OF ENGLISH MEDIUM SCHOOLS OF RAIPUR CITY - A STUDY

This paper focuses on learning style, school environment and home environment in relation to academic achievement. The research was carried out in Raipur city on a sample of 50 IX standard students. Learning styles of students was measured by Styles of Learning and Thinking (SOLAT) by D. Venkataraman. Home Environment and School Environment was measured by the Inventory prepared by Dr. Karuna Shankar Mishra. The research finding revealed that there is very low, negative & negligible relationship between academic achievement & home environment. Study also revealed that school environment and academic achievement have positive but very low relationship. It is also found that there is significant difference between the academic achievement of students learned by right & left hemisphere but there is no significant difference between the academic achievement of boys & girls students learned either by right hemisphere or left hemisphere.   Article visualizations

Down-regulation of DNMT3b in PC3 cells effects locus-specific DNA methylation, and represses cellular growth and migration

<p>Abstract</p> <p>Background</p> <p>Aberrations in DNA methylation patterns promote changes in gene expression patterns and are invariably associated with neoplasia. DNA methylation is carried out and maintained by several DNA methyltransferases (DNMTs) among which DNMT1 functions as a maintenance methylase while DNMT3a and 3b serve as de novo enzymes. Although DNMT3b has been shown to preferentially target the methylation of DNA sequences residing in pericentric heterochromatin whether it is involved in gene specific methylation remains an open question. To address this issue, we have silenced the expression of DNMT3b in the prostate-derived PC3 cells through RNA interference and subsequently studied the accompanied cellular changes as well as the expression profiles of selected genes.</p> <p>Results</p> <p>Our results demonstrate that DNMT3b depletion results in increased apoptosis and reduced migration of PC3 cells compared to the untransfected control cells. Reduced DNMT3b expression resulted in hypomethylation of retinoblastoma (Rb), retinoic-acid receptor β (RAR-β), and adenomatous polyposis coli (APC) gene promoters, and also culminated in increased expression of <it>CDKN3 </it>and <it>cytochrome b5</it>. Although DNMT3b silenced cells were found to have reduced growth and migratory potential, there was no apparent changes in their invasive ability compared to the parental PC3 cell line.</p> <p>Conclusion</p> <p>Our findings reveal that DNMT3b preferentially targets certain gene promoters in PC3 cells and that its depletion significantly reduces growth and migration of PC3 cells.</p

Management Of Subtrochanteric Femoral Fractures Using Proximal Femoral Nail

Background: Fractures of the proximal femur are a big challenge in traumatology. Rapid strides in implant and instrumentations in quest of ideal fixation of subtrochanteric femoral fractures have made various options available. Objective: The present study aims to study the role of standard proximal femoral nail (PFN) in the management of these fractures. This study aimed to evaluate the results of treatment of subtrochanteric femoral fractures using PFN. Patients and methods: This prospective study conducted at Orthopedic Department, Zagazig University Hospital, from November 2020 to July 2021. It included 24 patients, complaining of closed subtrochanteric fractures treated with PFN (Gamma intramedullary nail). The age ranged from 23 to 87 years (with mean 54.21 years), 13 of them were males and 11 females. Road traffic accident (RTA) represented the most common mechanism of injury in 10 patients (41.7%) while fall down represented (37.5%) in 9 patients, and fall from height in 5 patients (20.8%). Results: there was statistically significant difference in HHS among patients with different age groups, mechanism of injury and presence of diabetes mellitus (DM) as associated condition. Statistically there was significant correlation between type of reduction and diabetes mellitus with Harris hip score. Conclusion: This study concluded that the Gamma nail is an excellent choice in treatment of subtrochanteric fractures as it has many advantages as allowing for early functional exercise and full weight-bearing of the affected limb, shortening the duration of operation, high rotation stability, small wounds and minimizing blood loss along with risk of infectio

Nephron sparing surgery for renal tumors-Comparison of off-clamp partial nephrectomy with hilar clamping

Background and objective: Open partial nephrectomy (PN) is still considered gold standard procedure for T1 localized renal tumors. Conventional technique involves clamping of the renal artery with or without vein however, renal ischemia produces a certain level of damage to the kidneys. This study aims to investigate potential effect of off-clamp vs. hilar clamping PN on renal function.Methods: This is a retrospective cohort study of patients who underwent unilateral, open partial nephrectomy for renal tumors b/w January 2009 December 2016 at our institution. A total of 90 partial nephrectomies were performed of which 65 cases were eligible for analysis. Non clamping technique was used in 43 while clamp was applied in 22 patients. Variables studied were patients\u27 demographics, clinical variables, the laterality, tumors size and location, R.E.N.A.L nephrometry score, blood loss, tumor histology and surgical margins. Patients\u27 renal function (serum creatinine and eGFR) were determined pre-operatively, at 3 and 12 months follow up. Data was analyzed on SPSS v. 22.Results: Both the groups were comparable with regards to pre-operative renal function. Mean radiological size of tumor was 4.71±1.31 and 3.81±1.0 (0.003) in two groups respectively. Mean R.E.N.A.L nephrometry score was 6.1±1.5 in off-clamp group compared to 7.05 ± 1.7 in clamp group (p=0.04). No statistically significant difference was found in operative duration, blood loss, positive surgical margins and intra/ peri-operative complications. At three months and one year, renal function was better preserved in non-clamp group compared to clamp group (p=0.001 and 0.007 respectively).Conclusion: Off clamp open partial nephrectomy is safe and feasible option leading to less decline in renal function

Impact of COVID-19 on the pre and post analytical clinical laboratory testing processes- A performance evaluation study using six sigma

Background: The aim of this study was to determine the impact of COVID-19 pandemic on the total testing process using six sigma metrics based on a comparison of pre and during pandemic periods.Material & methods: The study duration was over 12 months, 6 months before and 6 months after the COVID-19 onset in Pakistan in March 2020 after the recognition of the first case, using quality indicators (QIs). QIs were chosen from a model of QIs recommended by the CAP. Analysis was performed using Six Sigma calculators and QIs were expressed in percentage (%) and Sigma value were computed. Three levels of performance quality i.e. 25th, 50th, and 75th percentile were derived, being best, common and worst performance respectively. Between-group differences were tested using the Mann-Whitney\u27s U test.Results: The median defect percentages of these QIs ranged from 0% to 0.27% for the pre-pandemic period and 0% to 0.13% for the during pandemic period. Meanwhile, sigma values of the majority of the QIs were all above 4.0σ during the pre and the pandemic times. For the pre-analytical phase, sigma scores declined for 1 QI, improved for 3 QIs and remained same for 2. In the post analytical phase, no change in sigma metrics was noted for critical values notification. Considerable increase in defect percentage of inappropriate turnaround times was noted.Conclusion: The emergency preparedness proved to be fruitful as depicted by exceptional performance on the sigma metrics for most Qis both prior to and during the pandemic. The pre-analytical and the post analytical phases, being the most error sensitive requires strict vigilance