95 research outputs found

    Investigation of Bird Strike Damage on Fokker 100 Airplane Wing and Nose

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    Bird strike or the collision of birds to the flying airplane is one of the common threats which reduces the safety of flying vehicles. Numerical analysis is so important to predict the behavior of airplanes body and nose in birds strike and it plays an important role to reduce the project cost and prevent unexpected damages. In this paper, it is tried to study the influence of birds strike on Fokker 100 airplane using the finite element method. In order to verify the proposed method, an experimental bird strike on a plane is studied. Then birds strike on the airplane wing and nose are numerically studied to investigate the amount of damage due to this phenomenon

    Analyse et design aérodynamique haute-fidélité de l'intégration moteur sur un avion BWB

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    Résumé Le BWB (Blended Wing Body) est un type d'avion à fuselage intégré basé sur le concept d'aile volante. Ce type d'avion offre des avantages au niveau économique et environnemental avec une réduction de la consommation de kérosène obtenue en améliorant la performance aérodynamique. Dans le cadre de ce projet, l'avion initial provient d'un design conceptuel. Il est donc nécessaire d'améliorer la performance aérodynamique grâce à l'optimisation du corps principal du BWB. Dans ce contexte, nous désirons utiliser les méthodes de haute-fidélité, ce qui est peu fréquent dans la littérature. Ce projet développe une méthode d'optimisation automatique afin de réduire la traînée sur le corps principal. On réalise l'optimisation en deux étapes principales : avant et après l'intégration moteur. Notre objectif est de réduire la traînée en prenant en compte plusieurs contraintes réalistes dans une optimisation à haute-fidélité. Le logiciel commercial Isight est choisi comme optimiseur et celui-ci appelle le logiciel MATLAB pour commencer le processus d'optimisation. La génération de la géométrie est réalisée à l'aide du logiciel ANSYS-DesignModeler. Pendand l'optimisation, on maille la géométrie de manière non-structurée à l’aide ANSYS - Mesh et les calculs CFD sont faits à l'aide d’ANSYS-Fluent. Le tout est fait dans l'environnement d’ANSYS-Workbench qui est appelé par MATLAB. La méthode haute-fidélité est utilisée pendant l'optimisation en résolvant les équations de Navier-Stokes. Dans chaque étape d'optimisation, en vue de vérifier les résultats, nous avons réalisé, grâce au logiciel ICEM, un remaillage de l'avion plus fin que le maillage utilisé dans l'optimisation et de manière structuré. La première étape comprend une optimisation 3D sur la surface du corps principal avant d'ajouter le moteur. En utilisant le cas optimisé comme donnée d'entrée, on passe à la deuxième optimisation en ajoutant la nacelle. D'abord, cette étude a permis d'obtenir une réduction convenable du coefficient de traînée du BWB sans nacelle. Ensuite, en ajoutant la nacelle, on peut également réduire la traînée en réalisant une optimisation du corps principal localement. Enfin, la séparation d'écoulement créée dans la zone corps-nacelle a été supprimée.----------Abstract BWB (Blended Wing Body) is an innovative type of aircraft based on the flying wing concept. In this configuration, the wing and the fuselage are blended together smoothly. BWB offers economical and environmental advantages by reducing fuel consumption through improving aerodynamic performance. In this project, the goal is to improve the aerodynamic performance by optimizing the main body of BWB that comes from conceptual design. The high fidelity methods applied in this project have been less frequently addressed in the literature. This research develops an automatic optimization procedure in order to reduce the drag force on the main body. The optimization is carried out in two main stages: before and after engine installation. Our objective is to minimize the drag by taking into account several constraints in high fidelity optimization. The commercial software, Isight is chosen as an optimizer in which MATLAB software is called to start the optimization process. Geometry is generated using ANSYS-DesignModeler, unstructured mesh is created by ANSYS-Mesh and CFD calculations are done with the help of ANSYS-Fluent. All of these software are coupled together in ANSYS-Workbench environment which is called by MATLAB. The high fidelity methods are used during optimization by solving Navier-Stokes equations. For verifying the results, a finer structured mesh is created by ICEM software to be used in each stage of optimization. The first stage includes a 3D optimization on the surface of the main body, before adding the engine. The optimized case is then used as an input for the second stage in which the nacelle is added. It could be concluded that this study leads us to obtain appropriate reduction in drag coefficient for BWB without nacelle. In the second stage (adding the nacelle) a drag minimization is also achieved by performing a local optimization. Furthermore, the flow separation, created in the main body-nacelle zone, is reduced

    The application of human Wharton's jelly mesenchymal stem cells in wound healing: A narrative review

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    Management and treatment of chronic wounds remain a significant problem in clinical practice. Stem cell therapies are an important and promising approach for regenerative medicine because of their self-renewal and differentiation potential. Mesenchymal stem cells (MSCs), a major cellular source for regeneration, are present in almost all tissues. The use of embryonic stem cells is morally controversial because of the need to nurture and destroy embryonic cells. Therefore, adult umbilical cord tissues are of particular importance as an alternative source of perinatal tissues. Wharton Jelly is a gelatinous connective tissue in the umbilical cord containing MSCs that can differentiate into osteogenic, adipose, chondrogenic, and other lineages. These cells do not express the MHC-II molecule and show immunomodulatory properties that make them viable for allogeneic and xenogenic transplants in cell therapy. Therefore, the umbilical cord, especially the part named Wharton's jelly, is an important and promising source of mesenchymal stem cells

    The Effect of Walnut (<i>Juglans regia</i>) Leaf Extract on Glycemic Control and Lipid Profile in Patients With Type 2 Diabetes Mellitus:A Systematic Review and Meta-Analysis of Randomized Clinical Trials

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    Numerous clinical trials have examined the beneficial effects of Juglans regia leaf extract (JRLE) in patients with type 2 diabetes mellitus (T2DM); however, the results of these studies are inconsistent. Therefore, we conducted the current systematic review and meta-analysis to evaluate the effect of JRLE on glycemic control and lipid profile in T2DM patients. We searched online databases including PubMed, Scopus, EMBASE, and Web of Science for randomized controlled clinical trials that examined the effect of JRLE on glycemic and lipid indices in T2DM patients. Data were pooled using both fixed and random-effect models and weighted mean difference (WMD) was considered as the overall effect size. Of the total records, 4 eligible studies, with a total sample size of 195 subjects, were included. The meta-analysis revealed that JRLE supplementation significantly reduces fasting blood glucose (WMD, −18.04; 95% confidence interval [CI], −32.88 mg/dL, −3.21 mg/dL; p = 0.017) and significantly increases fasting insulin level (WMD, 1.93; 95% CI, 0.40 U/L, 3.45 U/L; p = 0.014). Although the overall effect of JRLE supplementation on hemoglobin A1c was not significant, a significant reduction was seen in studies with an intervention duration of > 8 weeks (WMD, −0.64; 95% CI, −1.16%, −0.11%; p = 0.018). Moreover, we also found no significant change in lipid parameters. Our findings revealed a beneficial effect of JRLE supplementation on glycemic indices in T2DM patients, but no significant improvement was found for lipid profile parameters

    Relationship among plasma adipokines, insulin and androgens level as well as biochemical glycemic and lipidemic markers with incidence of PCOS in women with normal BMI

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    Polycystic ovary syndrome (PCOS) is an endocrine disorder in women. Omentin-1 and vaspin are secretary adipokines that are produced by the visceral adipose tissue. These levels change in obese women with PCOS. The aim of this study is to investigate whether omentin and vaspin levels change in nonobese PCOS subjects. This study is a cross-sectional case control study in which 39 women with PCOS were picked out for this study. The inclusion criteria were based on the Rotterdam 2003 diagnostic criteria. The control group consisted of 39 women with normal pelvic sonographic reports having regular menstruation and showing no signs of infertility. The fasting plasma glucose (FPG), triglyceride (TG), Chol, and high-density lipoprotein cholesterol (HDL-C), insulin, testosterone, omentin and vaspin were measured by the enzymatic methods. The differences within these groups were calculated by the un-paired t-test and the Mann–Whitney test. The results from this study show a significant increase in the amount of insulin, testosterone, homeostasis model assessments for insulin resistance, TG and lower HDL in the patient group. No significant differences were seen in omentin, vaspin, FPG, Cho, low-density lipoprotein, very low-density lipoprotein cholesterol, blood urea nitrogen, Cr and homeostasis model assessments for B cell function levels between groups. Results show that PCOS is not a determinant of decreased omentin and vaspin plasma levels and those high androgen level and insulin resistances are warning signs of PCOS

    Relationship among plasma adipokines, insulin and androgens level as well as biochemical glycemic and lipidemic markers with incidence of PCOS in women with normal BMI

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    Polycystic ovary syndrome (PCOS) is an endocrine disorder in women. Omentin-1 and vaspin are secretary adipokines that are produced by the visceral adipose tissue. These levels change in obese women with PCOS. The aim of this study is to investigate whether omentin and vaspin levels change in nonobese PCOS subjects. This study is a cross-sectional case control study in which 39 women with PCOS were picked out for this study. The inclusion criteria were based on the Rotterdam 2003 diagnostic criteria. The control group consisted of 39 women with normal pelvic sonographic reports having regular menstruation and showing no signs of infertility. The fasting plasma glucose (FPG), triglyceride (TG), Chol, and high-density lipoprotein cholesterol (HDL-C), insulin, testosterone, omentin and vaspin were measured by the enzymatic methods. The differences within these groups were calculated by the un-paired t-test and the Mann–Whitney test. The results from this study show a significant increase in the amount of insulin, testosterone, homeostasis model assessments for insulin resistance, TG and lower HDL in the patient group. No significant differences were seen in omentin, vaspin, FPG, Cho, low-density lipoprotein, very low-density lipoprotein cholesterol, blood urea nitrogen, Cr and homeostasis model assessments for B cell function levels between groups. Results show that PCOS is not a determinant of decreased omentin and vaspin plasma levels and those high androgen level and insulin resistances are warning signs of PCOS

    Frequency of virulence-associated genotypes of Helicobacter pylori and their correlation with clinical outcome and histological parameters in infected patients

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    Helicobacter pylori (H. pylori) is a gram-negative which can cause several gastroduodenal diseases, including gastritis and peptic ulcer disease (PUD). H. pylori specific genotypes have been related to increased occurrence of gastritis and PUD. The aim of this study was to investigate the clinical relevance of the major virulence factors of H. pylori with clinical outcomes and histological parameters in Iranian patients. Totally, 200 subjects with PUD and gastritis disease who underwent gastroduodenal endoscopy were enrolled in this study. The presence of the cagA, vacA, oipA, babA2, and iceA genes in antral gastric biopsy specimens were determined by polymerase chain reaction (PCR) and the results were compared with clinical outcomes and histological parameters. The frequency of babA2(+), oipA(+), vacA s1/m2, and vacA m2 genes was significantly higher in patients with peptic ulcer disease compared with patients with gastritis. In contrast, the frequency of vacA s1/m1 gene was significantly higher in gastritis subjects than PUD subjects. The high-density scores of H. pylori were strongly associated with iceA1, babA2(+), and oipA(+) genes. Additionally, the high polymorphonuclear cell infiltration and high mononuclear cell infiltration scores were strongly associated with the cagA(+), iceA1, oipA(+) genes and cagA(+), babA2(+), oipA(+) genes, respectively. Our study indicated that the vacA, babA2, and oipA virulence factors are related to a higher risk of PUD in subjects with H. pylori-infection. Infection with these strains was associated with a more severe gastropathy

    Socioeconomic inequalities in prevalence, awareness, treatment and control of hypertension: evidence from the PERSIAN cohort study

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    Background Elevated blood pressure is associated with cardiovascular disease, stroke and chronic kidney disease. In this study, we examined the socioeconomic inequality and its related factors in prevalence, Awareness, Treatment and Control (ATC) of hypertension (HTN) in Iran. Method The study used data from the recruitment phase of The Prospective Epidemiological Research Studies in IrAN (PERSIAN). A sample of 162,842 adults aged > = 35 years was analyzed. HTN was defined according to the Joint National Committee)JNC-7(. socioeconomic inequality was measured using concentration index (Cn) and curve. Results The mean age of participants was 49.38(SD = +/- 9.14) years and 44.74% of the them were men. The prevalence of HTN in the total population was 22.3%(95% CI: 20.6%; 24.1%), and 18.8%(95% CI: 16.8%; 20.9%) and 25.2%(95% CI: 24.2%; 27.7%) in men and women, respectively. The percentage of awareness treatment and control among individuals with HTN were 77.5%(95% CI: 73.3%; 81.8%), 82.2%(95% CI: 70.2%; 81.6%) and 75.9%(95% CI: 70.2%; 81.6%), respectively. The Cn for prevalence of HTN was -0.084. Two factors, age (58.46%) and wealth (32.40%), contributed most to the socioeconomic inequality in the prevalence of HTN. Conclusion The prevalence of HTN was higher among low-SES individuals, who also showed higher levels of awareness. However, treatment and control of HTN were more concentrated among those who had higher levels of SES, indicating that people at a higher risk of adverse event related to HTN (the low SES individuals) are not benefiting from the advantage of treatment and control of HTN. Such a gap between diagnosis (prevalence) and control (treatment and control) of HTN needs to be addressed by public health policymakers

    Mapping local patterns of childhood overweight and wasting in low- and middle-income countries between 2000 and 2017

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    A double burden of malnutrition occurs when individuals, household members or communities experience both undernutrition and overweight. Here, we show geospatial estimates of overweight and wasting prevalence among children under 5 years of age in 105 low- and middle-income countries (LMICs) from 2000 to 2017 and aggregate these to policy-relevant administrative units. Wasting decreased overall across LMICs between 2000 and 2017, from 8.4% (62.3 (55.1–70.8) million) to 6.4% (58.3 (47.6–70.7) million), but is predicted to remain above the World Health Organization’s Global Nutrition Target of <5% in over half of LMICs by 2025. Prevalence of overweight increased from 5.2% (30 (22.8–38.5) million) in 2000 to 6.0% (55.5 (44.8–67.9) million) children aged under 5 years in 2017. Areas most affected by double burden of malnutrition were located in Indonesia, Thailand, southeastern China, Botswana, Cameroon and central Nigeria. Our estimates provide a new perspective to researchers, policy makers and public health agencies in their efforts to address this global childhood syndemic

    Global, regional, and national burden of colorectal cancer and its risk factors, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

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    Funding: F Carvalho and E Fernandes acknowledge support from Fundação para a Ciência e a Tecnologia, I.P. (FCT), in the scope of the project UIDP/04378/2020 and UIDB/04378/2020 of the Research Unit on Applied Molecular Biosciences UCIBIO and the project LA/P/0140/2020 of the Associate Laboratory Institute for Health and Bioeconomy i4HB; FCT/MCTES through the project UIDB/50006/2020. J Conde acknowledges the European Research Council Starting Grant (ERC-StG-2019-848325). V M Costa acknowledges the grant SFRH/BHD/110001/2015, received by Portuguese national funds through Fundação para a Ciência e Tecnologia (FCT), IP, under the Norma Transitória DL57/2016/CP1334/CT0006.proofepub_ahead_of_prin
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