101 research outputs found

    Investigating the effect of rotational degree of freedom on a circular cylinder at low reynolds number in cross flow

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    Numerical simulations of Vortex-Induced Vibrations (VIV) of a circular cylinder in cross flow with a rotational degree of freedom about its axis have been carried out by means of a finite-volume method. The study is performed in two dimensions at a Reynolds number of Re D = 100, based on the free stream velocity and the diameter, D, of the cylinder. The effect of the rotational degree of freedom on the cylinder's lift and drag forces are compared with the baseline simulation results of flow around a stationary cylinder. The introduction of a rotational degree of freedom (d.o.f) is observed to cause the lift and drag forces to change. Also, the pattern of vortex shedding behind the cylinder is found to drastically change when the cylinder is allowed to rotate

    A comparative study of immersed-boundary interpolation methods for a flow around a stationary cylinder at low Reynolds number

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    The accuracy and computational efficiency of various interpolation methods for the implementation of non grid-confirming boundaries is assessed. The aim of the research is to select an interpolation method that is both efficient and sufficiently accurate to be used in the simulation of vortex induced vibration of the flow around a deformable cylinder. Results are presented of an immersed boundary implementation in which the velocities near nonconfirming boundaries were interpolated in the normal direction to the walls. The flow field is solved on a Cartesian grid using a finite volume method with a staggered variable arrangement. The Strouhal number and Drag coefficient for various cases are reported. The results show a good agreement with the literature. Also, the drag coefficient and Strouhal number results for five different interpolation methods were compared it was shown that for a stationary cylinder at low Reynolds number, the interpolation method could affect the drag coefficient by a maximum 2% and the Strouhal number by maximum of 3%. In addition, the bi-liner interpolation method took about 2% more computational time per vortex shedding cycle in companion to the other methods

    The effects of phenoxodiol on the cell cycle of prostate cancer cell lines

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    Background: Prostate cancer is associated with a poor survival rate. The ability of cancer cells to evade apoptosis and exhibit limitless replication potential allows for progression of cancer from a benign to a metastatic phenotype. The aim of this study was to investigate in vitro the effect of the isoflavone phenoxodiol on the expression of cell cycle genes. Methods: Three prostate cancer cell lines-LNCaP, DU145, and PC3 were cultured in vitro, and then treated with phenoxodiol (10 ÎĽM and 30 ÎĽM) for 24 and 48 h. The expression of cell cycle genes p21WAF1, c-Myc, Cyclin-D1, and Ki-67 was investigated by Real Time PCR. Results: Here we report that phenoxodiol induces cell cycle arrest in the G1/S phase of the cell cycle, with the resultant arrest due to the upregulation of p21WAF1 in all the cell lines in response to treatment, indicating that activation of p21WAF1 and subsequent cell arrest was occurring via a p53 independent manner, with induction of cytotoxicity independent of caspase activation. We found that c-Myc and Cyclin-D1 expression was not consistently altered across all cell lines but Ki-67 signalling expression was decreased in line with the cell cycle arrest. Conclusions: Phenoxodiol demonstrates an ability in prostate cancer cells to induce significant cytotoxicity in cells by interacting with p21WAF1 and inducing cell cycle arrest irrespective of p53 status or caspase pathway interactions. These data indicate that phenoxodiol would be effective as a potential future treatment modality for both hormone sensitive and hormone refractory prostate cancer

    Contribution of Intrinsic Reactivity of the HIV-1 Envelope Glycoproteins to CD4-Independent Infection and Global Inhibitor Sensitivity

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    Human immunodeficiency virus (HIV-1) enters cells following sequential activation of the high-potential-energy viral envelope glycoprotein trimer by target cell CD4 and coreceptor. HIV-1 variants differ in their requirements for CD4; viruses that can infect coreceptor-expressing cells that lack CD4 have been generated in the laboratory. These CD4-independent HIV-1 variants are sensitive to neutralization by multiple antibodies that recognize different envelope glycoprotein epitopes. The mechanisms underlying CD4 independence, global sensitivity to neutralization and the association between them are still unclear. By studying HIV-1 variants that differ in requirements for CD4, we investigated the contribution of CD4 binding to virus entry. CD4 engagement exposes the coreceptor-binding site and increases the “intrinsic reactivity” of the envelope glycoproteins; intrinsic reactivity describes the propensity of the envelope glycoproteins to negotiate transitions to lower-energy states upon stimulation. Coreceptor-binding site exposure and increased intrinsic reactivity promote formation/exposure of the HR1 coiled coil on the gp41 transmembrane glycoprotein and allow virus entry upon coreceptor binding. Intrinsic reactivity also dictates the global sensitivity of HIV-1 to perturbations such as exposure to cold and the binding of antibodies and small molecules. Accordingly, CD4 independence of HIV-1 was accompanied by increased susceptibility to inactivation by these factors. We investigated the role of intrinsic reactivity in determining the sensitivity of primary HIV-1 isolates to inhibition. Relative to the more common neutralization-resistant (“Tier 2-like”) viruses, globally sensitive (“Tier 1”) viruses exhibited increased intrinsic reactivity, i.e., were inactivated more efficiently by cold exposure or by a given level of antibody binding to the envelope glycoprotein trimer. Virus sensitivity to neutralization was dictated both by the efficiency of inhibitor/antibody binding to the envelope glycoprotein trimer and by envelope glycoprotein reactivity to the inhibitor/antibody binding event. Quantitative differences in intrinsic reactivity contribute to HIV-1 strain variability in global susceptibility to neutralization and explain the long-observed relationship between increased inhibitor sensitivity and decreased entry requirements for target cell CD4

    CD46 Protects against Chronic Obstructive Pulmonary Disease

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    BACKGROUND: Chronic obstructive pulmonary disease and emphysema develops in 15% of ex-smokers despite sustained quitting, while 10% are free of emphysema or severe lung obstruction. The cause of the incapacity of the immune system to clear the inflammation in the first group remains unclear. METHODS AND FINDINGS: We searched genes that were protecting ex-smokers without emphysema, using microarrays on portions of human lungs surgically removed; we found that loss of lung function in patients with chronic obstructive pulmonary disease and emphysema was associated with a lower expression of CD46 and verified this finding by qRT-PCR and flow cytometry. Also, there was a significant association among decreased CD46(+) cells with decreased CD4(+)T cells, apoptosis mediator CD95 and increased CD8(+)T cells that were protecting patients without emphysema or severe chronic obstructive pulmonary disease. CD46 not only regulates the production of T regulatory cells, which suppresses CD8(+)T cell proliferation, but also the complement cascade by degradation of C3b. These results were replicated in the murine smoking model, which showed increased C5a (produced by C3b) that suppressed IL12 mediated bias to T helper 1 cells and elastin co-precipitation with C3b, suggesting that elastin could be presented as an antigen. Thus, using ELISA from elastin peptides, we verified that 43% of the patients with severe early onset of chronic obstructive pulmonary disease tested positive for IgG to elastin in their serum compared to healthy controls. CONCLUSIONS: These data suggest that higher expression of CD46 in the lungs of ex-smoker protects them from emphysema and chronic obstructive pulmonary disease by clearing the inflammation impeding the proliferation of CD8(+) T cells and necrosis, achieved by production of T regulatory cells and degradation of C3b; restraining the complement cascade favors apoptosis over necrosis, protecting them from autoimmunity and chronic inflammation

    Distributed Control Design for Balancing the Grid Using Flexible Loads

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    International audienceInexpensive energy from the wind and the sun comes with unwanted volatility, such as ramps with the setting sun or a gust of wind. Controllable generators manage supply-demand balance of power today, but this is becoming increasingly costly with increasing penetration of renewable energy. It has been argued since the 1980s that consumers should be put in the loop: " demand response " will help to create needed supply-demand balance. However, consumers use power for a reason, and expect that the quality of service (QoS) they receive will lie within reasonable bounds. Moreover, the behavior of some consumers is unpredictable, while the grid operator requires predictable controllable resources to maintain reliability. The goal of this chapter is to describe an emerging science for demand dispatch that will create virtual energy storage from flexible loads. By design, the grid-level services from flexible loads will be as controllable and predictable as a generator or fleet of batteries. Strict bounds on QoS will be maintained in all cases. The potential economic impact of these new resources is enormous. California plans to spend billions of dollars on batteries that will provide only a small fraction of the balancing services that can be obtained using demand dispatch. The potential impact on society is enormous: a sustainable energy future is possible with the right mix of infrastructure and control systems

    Investigation Patients with Urinary Stones from the Aspect of Epidemiologic Parameters Admitted at Urology Department of Imam Reza Hospital During Years 2005-2008

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    Background: Urolithiasis is one of the most frequent diseases of urinary system which forms high percentage of patients who come to Urology wards. Therefore, study of epidemiological characteristics of patients of each ward can be helpful for making the best general decision. Methods: First, we devided 5133 cases who had come to Urology department of imam Reza hospital of mashhad during 2005-2008, in 2 groups and then in 6 groups. We investigated and compared 2 groups of lithotripsy and surgery from the aspect of epidemiological characteristics. So, we did for 6 groups: pyelolithotomy and nephrolithotomy, ureterolithotomy, ureteroscopy and TUL, PNL, ESWL, cystolitholapaxy. Results: From 5133 cases, mean age of 43.41, men to female ratio 2.1, 90.1% had done lithotripsy and 9.2% surgery. Percentage of patients of pyelolithotomy and nephrolithotomy was 3.5% ureterolithotomy 0.8%, ureteroscopy and TUL39.5%, PNL 4.9%, ESWL 49.5%, cystolitholapaxy 1.9%. Mean stay in hospital for 1.31±0.19 and for surgery 4.84±0.16, in ESWL 0.81±0.25 and in pyelolithotomy and nephrolithotomy 5.09±0.17 days. During years 2005-2008 percentage of ESWL was : 59.9, 51.4 & 38.4% of all admissions in these years. PNLs percentage was: 3.8, 5.51, 5.53%. Choosing of PNL in urban people was highest (84.5%) and for rural people pyelolithotomy and nephrolithotomy is the most technique in use. Conclusion: Despite of other advanced countries high percentage of our patients undergo open surgery especially in rural people, yet. So, we should provide facilities of education and financials for modern and lower costs of urinary tract stone treatments

    Investigating the Correlation between rs1049305 and ‏rs10244884 Polymorphisms of AQP-1 Gene and Menorrhagia ‎in Adolescents

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    Introduction: Aquaporins (AQPs) are water channels present in the cell wall, allowing water – ‎and occasionally other molecules – to pass the cell membrane. Their function is to maintain the ‎ internal milieu cells by regulating water and ion equilibrium. The endometrium undergoes ‎structural changes during the menstrual cycle. If implantation does not occur at the end of each ‎menstrual cycle, amplified endometrium is shed in absence of hormones and leads to ‎bleeding. Excessive uterine bleeding over 80 cc in each menstrual cycle called ‎menorrhagia, is a common gynecological disorder which causes large menstrual bleedings ‎and reduced quality of life for those affected.‎ Methods: The study included 37 patients with menorrhagia and 20 healthy ‎individuals. Genomic DNA was extracted from peripheral blood and Genotypes were determined ‎by ARMS-PCR and PCR-RFLP .Statistical analysis was performed using the SPSS ‎program. ‎ Results: Regarding ‏‎rs1049305, the C minor allele showed more frequency in patients' group‏ (0.47 vs. 0.37).‎‎ The results revealed that GG genotype presents less probable risk ‎for menorrhagia. ‎‎ rs10244884‎ also shows the same frequency. Conclusion: It can be concluded that both variants are important in pathogenesis of menorrhagia and the results confirm the important role of Aquqporin–1 channel in menstruation as well as endometrium physiology

    Diagnostic validity of BCL-2 in ganglion cell staining and its application in Hirschprung’s disease diagnosis

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    Background and Objective: Hirschsprung’s disease is a congenital disorder, characterized by the absence of ganglion cells in the intramural and submucosal plexus in distal parts of large bowel. Diagnosis is based on the histopathologic examination of hematoxilin and eosin stained sections. Due to diagnosis limitation by Hematoxylin and Eosin staining (H&E), this study was done to identify the ganglion cells by BCL-2 immunoreactivity and compared it with H&E staining. Materials and Methods: In this laboratory study, paraffin blocks of 36 specimens demonstrating ganglion cells on original H&E stained sections and 35 specimens lacking ganglion cells on H&E staining, were selected. Recuts were stained by H&E and BCL-2 methods. Results: Ganglion cells were observed in 36 cases by H&E staining but in BCL-2 staining ganglion cells were detected in 29 cases. In 35 cases reported negative for ganglion cells on H&E staining, ganglion cells were detected in 5 cases by BCL-2 method. Sensitivity, spesificity, positive and negative predictive values for BCL-2 method for diagnosis of hirshsprung’s disease were 81%, 86%, 85% and 86% respectively.discordancy (positive BCL-2, negative H&E) was 14%. Conclusion: Immunohistochemistry method using BCL-2 improve the accuracy of diagnosis in hirschsprung’s disease, when accompanied with H&E staining, particulary for negative slides
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