112 research outputs found

    Vibration Control in MEMS Resonator Using Positive Position Feedback (PPF) Controller

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    In this paper, the vibration of a micro-electromechanical resonator with positive position feedback controller is studied. The analytical results are obtained to the first order approximation by using the multiple scale perturbation technique. The stability of the steady-state solution is presented and studied applying frequency response equations near the simultaneous primary and internal resonance cases. The effects of the controller and some system parameters on the vibrating system are studied numerically. The main result of this paper indicates that it is possible to reduce the vibration for the resonator system

    An Optimization Model For Guiding The Petrochemical Industry Development In Saudi Arabia

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    A mixed integer linear programming model is formulated for determining the optimum plan for the expansion of the Saudi Arabian petrochemical industry. The products selected for consideration fall into four categories: propylene derivatives, ethylene derivatives, synthesis gas derivatives, and aromatic derivatives. The model incorporates new variables and constraints, and realistic estimates of production costs, which are calculated based on local conditions in Saudi Arabia. For each production process, the unit production cost is assumed to be a function of production capacity. The input data for each product includes relevant production technologies, capacities, local production costs, and selling price. The solution of the model gives the recommended products under different scenarios of available capital investment and feedstock. The results are reported and analyzed

    Factors associated with poor glycemic control among type-2 diabetes mellitus patients in Yemen

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    Purpose: To determine the status of glycemic control and its associated factors among adult patients with type 2 diabetes mellitus (T2DM) in Hodeidah City, Yemen. Methods: This cross-sectional study involved T2DM patients attending an outpatient clinic at the Military Hospital in Hodeidah, from January to March 2017. Relevant socio-demographic characteristics, clinical factors and self-management behaviours were recorded in face-to-face interviews. Blood pressure, body weight, and height measurements were also obtained. Glycosylated hemoglobin (HbA1c) and lipid profile were evaluated. Urine samples were also obtained and analysed by albuminuria assay. Results: Of 246 participants, 73.2 % showed poor glycemic control (HbA1c ≥ 7 %). Female patients, those aged ≥ 40 years, the illiterate, and Khat chewers were more likely to have poor glycemic control. Moreover, longer disease duration, insulin administration and albuminuria were significantly associated with poor glycemic control. In contrast, a healthy diet, physical exercise, proper self-monitoring of blood glucose levels and taking medicines as prescribed significantly increased the likelihood of good glycemic control. Conclusion: A majority of the Yemeni diabetic patients have poor glycemic control. To achieve better awareness, diabetes educational programs that highlight the benefits of self-management are recommended

    Anatomical Variations in Palmar Creases and Their Correlation to The Intelligence Capacity of Libyan Medical and Dental Students of Omar Al-Mukhtar University.

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    Background: For centuries, clinicians, anthropologists, and palmists have found the creases in the palm interesting. However, only in the last fifty years that research's started to examine the variations in these creases. Based on the three main palmar creases, thenar, proximal, and distal transverse creases, four patterns of palmar creases are identified; nonvariant, Sydney, Suwon, and simian. Previous studies of palmar creases revealed that familial components, race, sex, and age are factors that influence the expression of palmar crease patterns. Simian patterns of palmar creases are linked to various congenital diseases, some characterized by low level of intelligence. Aim: This paper aims to investigate the variations in palmar crease patterns among medical and dental students of Omar Al-Mukhtar University and to study the range of intelligence capacity associated with each pattern. Materials and methods: The study was conducted on 183 students. A paper-based IQ test was performed and photos were taken from both palms of all participants. Results: Out of 183 participants, the nonvariant pattern of palmar creases was found in 92%, in which, 100 students have bilateral 2 points of origin palmar creases and 48 students have bilateral 3 points of origin palmar creases, whereas 18 participants have one palm of 2 points and the other palm of 3 points of origin. Unilateral simian was the dominant type in the aberrant palmar creases, followed by bilateral Sydney, then unilateral Sydney, and Suwon. Conclusion: The students with unilateral simian have the highest average score of 47.166 followed by bilateral nonvariant and unilateral nonvariant. Students with unilateral Sydney have the lowest average score of 41

    Favorable Changes in Fasting Glucose in a 6-month Self-Monitored Lifestyle Modification Programme Inversely Affects Spexin Levels in Females with Prediabetes

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    Spexin (SPX) is a novel peptide thought to have a role in various metabolic regulations. Given its presumed body-weight regulatory functions, we aimed to determine whether lifestyle intervention programs on weight loss and fasting glucose (FG) improvement among people with impaired glucose regulation also alter levels of circulating SPX. A total of 160 Saudi adult males and females with prediabetes were randomly selected from a larger cohort (N = 294) who underwent a 6-month lifestyle modification program to improve their glycemic status. Participants were split into two groups based on differences in glucose levels post-intervention, with the first 50% (improved group) having the most significant reduction in FG. SPX was measured at baseline and after 6 months. Changes in SPX was significant only in the improved group [baseline: median (Q1\u2013Q3) of 164 pg/ml (136\u2013227) vs follow-up: 176 pg/ml (146\u2013285); p < 0.01]. When stratified by sex, the significant increase was observed only in females [159 pg/ml (127\u2013252) vs 182.5 (152,369.1); p < 0.01]. Furthermore, SPX levels showed a significant inverse association with FG (\u3b2 = 120.22, p = 0.003) even after adjustment with age and BMI, again only in females. Circulating SPX levels increase over time in people with prediabetes, particularly women who responded favorably in a 6-month lifestyle intervention program. Whether an unknown mechanism regulating the sexual disparity seen in SPX levels post-intervention exists should be further investigated using a larger sample size

    Standardized outcome measures for pregnancy and childbirth, an ICHOM proposal

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    Background: Value-based health care aims to optimize the balance of patient outcomes and health care costs. To improve value in perinatal care using this strategy, standard outcomes must first be defined. The objective of this work was to define a minimum, internationally appropriate set of outcome measures for evaluating and improving perinatal care with a focus on outcomes that matter to women and their families. Methods: An interdisciplinary and international Working Group was assembled. Existing literature and current measurement initiatives were reviewed. Serial guided discussions and validation surveys provided consumer input. A series of nine teleconferences, incorporating a modified Delphi process, were held to reach consensus on the proposed Standard Set. Results: The Working Group selected 24 outcome measures to evaluate care during pregnancy and up to 6 months postpartum. These include clinical outcomes such as maternal and neonatal mortality and morbidity, stillbirth, preterm birth, birth injury and patient-reported outcome measures (PROMs) that assess health-related quality of life (HRQoL), mental health, mother-infant bonding, confidence and success with breastfeeding, incontinence, and satisfaction with care and birth experience. To support analysis of these outcome measures, pertinent baseline characteristics and risk factor metrics were also defined. Conclusions: We propose a set of outcome measures for evaluating the care that women and infants receive during pregnancy and the postpartum period. While validation and refinement via pilot implementation projects are needed, we view this as an important initial step towards value-based improvements in care

    New insights into the genetic etiology of Alzheimer's disease and related dementias

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    Characterization of the genetic landscape of Alzheimer's disease (AD) and related dementias (ADD) provides a unique opportunity for a better understanding of the associated pathophysiological processes. We performed a two-stage genome-wide association study totaling 111,326 clinically diagnosed/'proxy' AD cases and 677,663 controls. We found 75 risk loci, of which 42 were new at the time of analysis. Pathway enrichment analyses confirmed the involvement of amyloid/tau pathways and highlighted microglia implication. Gene prioritization in the new loci identified 31 genes that were suggestive of new genetically associated processes, including the tumor necrosis factor alpha pathway through the linear ubiquitin chain assembly complex. We also built a new genetic risk score associated with the risk of future AD/dementia or progression from mild cognitive impairment to AD/dementia. The improvement in prediction led to a 1.6- to 1.9-fold increase in AD risk from the lowest to the highest decile, in addition to effects of age and the APOE ε4 allele

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe
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