A semi-analytical approach for the response of nonlinear conservative systems

This work applies Parameter expanding method (PEM) as a powerful analytical technique in order to obtain the exact solution of nonlinear problems in the classical dynamics. Lagrange method is employed to derive the governing equations. The nonlinear governing equations are solved analytically by means of He’s Parameter expanding method. It is demonstrated that one term in series expansion is sufficient to generate a highly accurate solution, which is valid for the whole domain of the solution and system response. Comparison of the obtained solutions with the numerical ones indicates that this method is an effective and convenient tool for solving these types of problems

The performance of deterministic and stochastic interest rate risk measures : Another Question of Dimensions?

The efficiency of traditional and stochastic interest rate risk measures is compared under one-, two-, and three-factor no-arbitrage Gauss-Markov term structure models, and for different immunization periods. The empirical analysis, run on the German Treasury bond market from January 2000 to December 2010, suggests that: i) Stochastic interest rate risk measures provide better portfolio immunization than the Fisher-Weil duration; and ii) The superiority of the stochastic risk measures is more evident for multi-factor models and for longer investment horizons. These findings are supported by a first-order stochastic dominance analysis, and are robust against yield curve estimation errors.info:eu-repo/semantics/publishedVersio

Clinical efficacy of convalescent plasma for treatment of COVID-19 infections: Results of a multicenter clinical study

Since Dec. 2019 the new coronavirus (SARS-CoV-2) has infected millions and claimed life of several hundred thousand worldwide. However, so far no approved vaccine or drug therapy is available for treatment of virus infection. Convalescent plasma has been considered a potential modality for COVID-19 infection. One hundred eighty-nine COVID-19 positive patients including 115 patients in plasma therapy group and 74 patients in control group, registered in the hospitals with confirmed COVID-19 infection, entered this multi-center clinical study. Comparison of outcomes including all-cause mortality, total hospitalization days and patients� need for intubation between the two patient groups shows that total of 98 (98.2 ) of patients who received convalescent plasma were discharged from hospital which is substantially higher compared to 56 (78.7 ) patients in control group. Length of hospitalization days was significantly lower (9.54 days) in convalescent plasma group compared with that of control group (12.88 days). Only 8 patients (7) in convalescent plasma group required intubation while that was 20 in control group. This clinical study provides strong evidence to support the efficacy of convalescent plasma therapy in COVID-19 patients and recommends this treatment for management of these patients. Clinical efficacy, immediate availability and potential cost effectiveness could be considered as main advantages of convalescent plasma therapy. © 2020 Elsevier Lt

Loss of expression of TGF-βs and their receptors in chronic skin lesions induced by sulfur mustard as compared with chronic contact dermatitis patients

<p>Abstract</p> <p>Background</p> <p>Sulfur mustard (SM) is a blister-forming agent that has been used as a chemical weapon. Sulfur mustard can cause damage in various organs, especially the skin, respiratory system, and eyes. Generally, the multiple complications of mustard gas result from its alkalizing potency; it reacts with cellular components like DNA, RNA, proteins, and lipid membranes.</p> <p>TGF-β is a multi-functional cytokine with multiple biological effects ranging from cell differentiation and growth inhibition to extracellular matrix stimulation, immunosuppression, and immunomodulation. TGF-β has 3 isoforms (TGF-β 1, 2, 3) and its signaling is mediated by its receptors: R1, R2 and intracellular Smads molecules.</p> <p>TGF-β has been shown to have anti-inflammatory effects. TGF-βs and their receptors also have an important role in modulation of skin inflammation, proliferation of epidermal cells, and wound healing, and they have been implicated in different types of skin inflammatory disorders.</p> <p>Methods</p> <p>Seventeen exposed SM individuals (48.47 ± 9.3 years), 17 chronic dermatitis patients (46.52 ± 14.6 years), and 5 normal controls (44.00 ± 14.6 years) were enrolled in this study.</p> <p>Evaluation of TGF-βs and their receptors expressions was performed by semiquantitative RT-PCR. Only TGF1was analyzed immunohistochemically.</p> <p>Results</p> <p>Our results showed significant decreases in the expression percentages of TGF-β 1, 2 and R1, R2 in chemical victims in comparison with chronic dermatitis and normal subjects and significant decreases in the intensity of R1 and R2 expressions in chemical victims in comparison with chronic dermatitis and normal controls. (P value < 0.05)</p> <p>Conclusions</p> <p>TGF-βs and their receptors appear to have a noticeable role in chronic inflammatory skin lesions caused by sulfur mustard.</p

Przybliżone rozwiązanie analityczne dla belek Bernoulliego-Eulera opartych na nieliniowym podłożu winklerowskim przy różnych warunkach zamocowania

In this study, a powerful analytical method, known as Homotopy Analysis Method (HAM), is used to obtain an analytical solution to nonlinear ordinary deferential equations arising for Bernoulli-Euler beams with a non-linear foundation of the Winkler type. A comparison between the HAM solution and a solution obtained by a numerical method is made to show the accuracy of the method. It is shown that the present solution is valid for the whole domain of the solution and also for high nonlinear terms, where other methods such as the perturbation method fail to converge. The results clearly indicate that the convergence region can be controlled and adjusted by HAM. Finally, after validating the results, the effect of constant parameters on the deflection and slope for different boundary conditions is presented.W pracy przedstawiono zastosowanie bardzo wszechstronnej metody homotopii (HAM) do uzyskania analitycznego rozwiązania nieliniowych równań różniczkowych opisujących drgania belek Bernoulliego-Eulera spoczywających na nieliniowym podłożu winklerowskim. W celu zaprezentowania dokładności metody, uzyskane wyniki porównano z rezultatami symulacji numerycznych. Wykazano, że tak otrzymane rozwiązanie jest ważne w całej dziedzinie, także przy uwzględnieniu członów nieliniowych wyższego rzędu. Inne metody, m.in. analiza perturbacyjna, przestają być w takich przypadkach zbieżne. Przeprowadzone badania wyraźnie dowodzą, że obszar zbieżności może być monitorowany i dostosowywany w ramach metody HAM. Na zakończenie rozważań, po weryfikacji obliczeń, przedyskutowano wpływ stałych parametrów układu na ugięcie i kąt ugięcia belek przy równych warunkach zamocowania

Study of infertile husbands’ and wives’ point of view to infertility and marital adjustment in patients reffering to Royan infertility center of Tehran in 2005

Background and purpose: The rate of infertility is estimated 12-21% in Iranian couples. Cooperation of couples is needed for treatment. One potential risk factor for the development of marital problems is difference between partners in their approach to infertility. The aim of this study was to know the infertile couples' approach to infertility and marital adjustment.Materials and Methods: In this cross sectional study, 160 infertile couples reffering to Royan infertility center of Tehran were enrroled. The data concerning the infertility approach and marital adjustment were recorded in, Copper Smith self esteem and Dyadic adjustment scale (DAS) questionaire. SPSS soft ware was used for the ststistical analysis of the data.Results: Findings showed that having children was very important to both husbands and wives and both involved in and wanted to talk about trying to have a baby. There was no difference between self esteem and marital adjustment in men and women. There was ststistically significant difference between approach to infertility and marital adjustment in both husbands and wives.Conclusion: Husbands’ and wives’ approach to infertility and marital adjustment can be used by psychologists in evaluation of infertile couples. Increase of couple interest and involvement in infertility treatment may lead to positive change in couples communication about infertility and to a more positive effect of infertility on the marriage

A Novel Classification Method using Effective Neural Network and Quantitative Magnetization Transfer Imaging of Brain White Matter in Relapsing Remitting Multiple Sclerosis

Background: Quantitative Magnetization Transfer Imaging (QMTI) is often used to quantify the myelin content in multiple sclerosis (MS) lesions and normal appearing brain tissues. Also, automated classifiers such as artificial neural networks (ANNs) can significantly improve the identification and classification processes of MS clinical datasets. Objective: We classified patients with relapsing-remitting multiple sclerosis (RRMS) from healthy subjects using QMTI and T1 longitudinal relaxation time data of brain white matter and the performance of three ANN-based classifiers have been investigated. Materials and Methods: Conventional magnetic resonance imaging (MRI) and quantitative magnetization transfer scans were obtained from RRMS patients (n=30) and age-matched healthy subjects (n=30). After image pre-processing and brain tissue segmentation, QMTI parameters including magnetization transfer ratio (MTR), magnetization transfer rate (Ksat), T1 relaxation time under MT saturation pulse (T1sat) and T1 longitudinal relaxation time were calculated as parametric maps. Three ANN algorithms, including multilayer perceptron (MLP), radial basis function (RBF) and ensemble neural network based on Akaike information criterion (ENN-AIC) input features were extracted in the form of QMTI and T1 mean values. The ANNs quantitative performance is measured by the standard evaluation of confusion matrix criteria. Results: The results indicate that ENN-AIC-based classification method has achieved 90% accuracy, 92% sensitivity and 86% precision compared to other ANN classification models such as RBF and MLP. NPV, FPR and FDR values of the proposed ENN-AIC model were found to be 0.933, 0.125 and 0.133, respectively. A graphical representation of how to track actual data by the predictive values derived from each of the three algorithms, was also presented. It has been demonstrated that ENN-AIC as an effective neural network improves the quality of classification results compared to MLP and RBF. Conclusion: The efficiency and robustness of ENN classifier will greatly enhance with the use of AIC-based combination weights assignment. In addition, this research provides a new direction to classify a large amount of quantitative MRI data that can help the physician in a correct MS diagnosis

A Semi-Analytical Approach for the Response of Nonlinear Conservative Systems

This work applies Parameter expanding method (PEM) as a powerful analytical technique in order to obtain the exact solution of nonlinear problems in the classical dynamics. Lagrange method is employed to derive the governing equations. The nonlinear governing equations are solved analytically by means of He’s Parameter expanding method. It is demonstrated that one term in series expansion is sufficient to generate a highly accurate solution, which is valid for the whole domain of the solution and system response. Comparison of the obtained solutions with the numerical ones indicates that this method is an effective and convenient tool for solving these types of problems

Can Estradiol and Ghrelin Play a Protective Role in Epithelial Ovarian Cancer Incidence in Postmenopausal Women?

Objective: The present study aimed to investigate the association between estradiol, n-octanoylated, des-octanoylated, total ghrelin, and ghrelin/des-octanoylated ghrelin ratio levels along with pathological parameters and epithelial ovarian cancer (EOC) odds in postmenopausal women. Materials and Methods: A case-control study was carried out on 45 patients with EOC and 33 age-matched postmenopausal women as the control group. Plasma levels of estradiol, n-octanoylated, des-octanoylated, and total ghrelin were measured by ELISA method. Results: Estradiol's plasma levels were significantly higher in patients with EOC than in control women (p &lt;0.001). Although the ratio levels of n-octanoylated, des-octanoylated, total ghrelin, and ghrelin/des-octanoylated ghrelin were not associated with EOC in logistic regression models, estradiol levels were significantly related to the increase in EOC odds (OR: 1.083, 95 CI: 1.037�1.13, p &lt;0.001). However, estradiol levels in the two first quartiles (Q1, Q2) were associated with decreased odds of EOC (OR: 0.011, 95 CI: 0.001�0.118, p &lt;0.001, and OR: 0.030, 95 CI: 0.003�0.284, p = 0.002, respectively). For those patients in the third quartile of plasma des-octanoylated and total ghrelin compared to those in the highest (Q4), the multivariate odds ratios of EOC were respectively 0.192 and 0.25. Conclusion: In conclusion, higher concentrations of des-octanoylated and total ghrelin might be associated with the decreased EOC odds. Furthermore, the findings suggest that high levels of estradiol might be a potential odds factor in EOC, however, lower estradiol levels may have a protective effect on EOC development. © 2020 IMS