Nonlinear free vibration analysis of the functionally graded beams

Nonlinear natural oscillations of beams made from functionally graded material (FGM) are studied in this paper. The equation of motion is derived according to the EulerBernoulli beam theory and von Karman geometric nonlinearity. Subsequently, Galerkin’s solution technique is applied to obtain the corresponding ordinary differential equation (ODE) for the FGM beam. This equation represents a kind of a nonlinear ODE containing quadratic and cubic nonlinear terms. This nonlinear equation is then solved by means of three efficient approaches. Homotopy perturbation method is applied at the first stage and the corresponding frequency-amplitude relationship is obtained. Frequency-amplitude formulation and Harmonic balance method are then employed and the consequent frequency responses are determined. In addition, Parameter Expansion Method is utilized for evaluating the nonlinear vibration of the system. A parametric study is then conducted to evaluate the influence of the geometrical and mechanical properties of the FGM beam on its frequency responses. Different types of material properties and boundary conditions are taken into account and frequency responses of the system are evaluated for different gradient indexes. The frequency ratio (nonlinear to linear natural frequency) is obtained in terms of the initial amplitude and compared for different materials and end conditions

Modeling and control of flatness in cold rolling mill using fuzzy petri nets

Today, having a good flatness control in steel industry is essential to ensure an overall product quality, productivity and successful processing. Flatness error, given as difference between measured strip flatness and target curve, can be minimized by modifying roll gap with various control functions. In most practical systems, knowing the definition of the model in order to have an acceptable control is essential. In this paper, a fuzzy Petri net method for modeling and control of flatness in cold rolling mill is developed. The method combines the concepts of Petri net and fuzzy control theories. It focuses on the fuzzy decision making problems of the fuzzy rule tree structures. The method is able to detect and recover possible errors that can occur in the fuzzy rule of the knowledge-based system. The method is implemented and simulated. The results show that its error is less than that of a PI conventional controller.<br /

Clinical trial of the effects of coenzyme Q10 supplementation on glycemic control and markers of lipid profiles in diabetic hemodialysis patients

Abstract Purpose: The current study was conducted to determine the effects of coenzyme Q10 (CoQ10) supplementation on glycemic control and markers of lipid profiles risk in diabetic hemodialysis (HD) patients. Methods: This randomized, double blind, placebo-controlled clinical trial was performed among 60 diabetic HD patients. Subjects were randomly allocated into two groups to take either 120 mg/day of CoQ10 supplements or placebo (n= 30each group) for 12 weeks. Results: After 12 weeks of intervention, CoQ10 supplementation, compared with the placebo, resulted in a significant decrease in serum insulin concentrations (− 2.5 ± 4.0 vs.+ 2.8 ± 5.3 μIU/mL, P < 0.001), homeostasis model of assessment estimated insulin resistance (− 0.9 ± 2.1 vs. + 1.2 3.0, P = 0.002), and significant increase in the quantitative insulin sensitivity check index (+ 0.009 ± 0.01 vs. − 0.02 ± 0.05, P = 0.003). In addition, a trend toward a greater decrease in serum triglycerides (− 5 ± 53 vs. + 17 ± 44, P = 0.078) and VLDL-cholesterol levels (− 0.9 ± 10 vs. + 3 ± 9, P = 0.078) was observed in the CoQ10 group compared to the placebo group. We did not observe any significant effect of CoQ10 supplementation on fasting glucose, HbA1c and other lipid profiles compared with the placebo. Conclusions: Overall, our study supported that CoQ10 supplementation to diabetic HD patients for 12 weeks had beneficial effects on markers of insulin metabolism, but did not affect fasting glucose, HbA1c, and lipid profiles. Keywords: Coenzyme Q10 supplementation · Hemodialysis · Glycemic control · Lipid profile

Pantic B-spline wavelets and their application for solving linear integral equations

Abstract In this work we deal with the question: how can one improve the approximation level for some nonlinear integral equations? Good candidates for this aim are semi orthogonal B-spline scaling functions and their duals. Although there are different works in this area, only B-spline of degree at most 2 are used for this approximation. Here we compute B-spline scaling functions of degree 4 and their duals, then we will show that, by using them, one can have better approximation results for the solution of integral equations in comparison with less degrees or other kinds of scaling functions. Some numerical examples show their attractiveness and usefulness

Comparison of the Effect of Yoghurt Starter Bacteria and Lactobacillous Bulgaricus on Peripheral Blood Mononuclear Cells Activity of Ulcerative Colitis Patients

BACKGROUND AND OBJECTIVE: Ulcerative colitis is an inflammatory bowel disease and involving colon and rectum. Since patients with ulcerative colitis have high levels of pro-inflammatory and anti-inflammatory cytokines, the aim of this study was to compare the effects of starter bacteria of yogurt and lactobacillus boulagaricus on the activity of peripheral blood mononuclear cells in patients with ulcerative colitis. METHODS: This experimental-laboratory study was performed on 10 ulcerative colitis patients in Dezful, Andimeshk and Shoosh in two experimental groups and a control group. Experimental groups included co-culture of PBMC and intended bacteria in dilutions of 0.1 and 0.01 and at 48 and 72 hours, and control group including PBMC of the patient at 48 and 72 hours. Variables IL-10 and IL-1β) were measured by ELISA. FINDINGS: There was a significant increase in the secretion of IL1β at dilution of 0.1 and 48 hours by PBMC stimulated with bulgaricus 940.4±249.61 in comparison with the starter 669.12±181.11 (p=0.004) and in 72 hours by bulgaricus 796.3±213.34 in comparison with the starter 464.25±128.41 (p=0.000), In dilution of 0.01 and 48 hours by bulgaricus 747.5±198.54 in comparison with starter 529.25±163.82 (p=0.005) and in 72 hours by bulgaricus 617.4±192.5 in comparison with starter 408.62±134.78 (P=0.004). Also, there was a significant increase in the secretion of cytokines in both dilution and both times between of the experimental groups and control. CONCLUSION: The results of the study showed that Lactobacillus bulgaricus causes inflammation in comparison with the starter by IL1β secretion. Starter bacteria has a better role in reducing inflammation

Clinical trial of the effects of coenzyme q10 supplementation on biomarkers of inflammation and oxidative stress in diabetic hemodialysis patients

Background: The aim of the study was to determine the effects of coenzyme Q10 (CoQ10) supplementation on biomarkers of inflammation and oxidative stress among diabetic hemodialysis (HD) patients. Methods: Sixty diabetic HD patients participated in the randomized, double blind, placebo-controlled clinical trial. They were randomly assigned into two groups to intake either 60 mg CoQ10 supplements (n = 30) or placebo (n = 30) twice a day for 12 weeks. Results: After 12 weeks of intervention, CoQ10 supplementation significantly increased total antioxidant (TAC) (54.921 ± 26.437 vs. -126.781 ± 26.437, P < 0.001) and nitric oxide (NO) levels (4.121 ± 1.314 vs. -1.427 ± 1.314, P = 0.006) and decreased C-reactive protein (CRP) (-1.302 ± 0.583 vs. 0.345 ± 0.583, 0.042) levels compared with the placebo. We did not observe any significant effect of CoQ10 supplementation on malondialdehyde (MDA) and glutathione (GSH) levels compared with the placebo. Conclusions: Overall, our study showed that CoQ10 supplementation to diabetic HD patients for 12 weeks was associated with increased levels of TAC and NO levels and decreased level of high-sensitivity CRP (hs-CRP) levels, but did not have any beneficial effects on MDA and GSH. © 2019 International Journal of Preventive Medicine

Characterizations physicochemical and microbiological of dried figs collected from the markets of Rabat-Sale, Temara and Casablanca

Les figues sont des fruits de Ficus carica L., un membre de la famille  Moraceae. Figue est connue comme un fruit sain en raison de ses hautes fibres alimentaires et la teneur en minéraux. Figues sont généralement  consommées comme séchée. La présente étude évalue les caractérisations physico-chimiques et microbiologiques de 72 échantillons de la figue sèche, prélevés des marchés de Rabat et Casablanca. Les résultats obtenus ont montré que les échantillons prélevés des  marchés de Rabat présentent le taux de contamination le plus élevé avec une charge moyenne élevée du Coliformes totaux, Coliformes fécaux, Levures et Moisissures et un potentiel d’oxydo-réduction et une acidité très bas. Les échantillons les moins contaminés ont été prélevés des marchés de Casablanca.  L’identification des germes pathogènes, isolés pour l’ensemble des échantillons prélevés, a montré que les Enterobacter est le genre le plus fréquent (45%). Par contre, d’autres genres présentent un taux moins élevé tels: Klebsiella (30%), Buttiaux agrestis (5%), Serratia marcescens (10%) et Escherichia Coli (10%). Enfin, nous avons remarqué que l’étude de la sensibilité des souches isolées vis-à-vis de 12 antibiotiques, a montré une certaine résistante pour l'ampicilline, l’amoxicilline, l’amoxicilline+Acide clavulanique, la céfalotine la ticarcilline et le co-trimoxazole.Figs are fruits of Ficus carica L., a member of the family Moraceae. Fig is known as a healthy fruit due to its high dietary fiber and mineral content. Figs are usually consumed as dried. This study evaluates the characterizations physicochemical and microbiological of 72 samples of dry figs, taken from markets of Rabat and Casablanca. The results showed that samples of the markets of Rabat have the highest contamination level with average high total coliform, fecal coliforms, yeasts and moulds and redox potential and acidity very low. The least contaminated samples were collected in the markets of Casablanca. The identification of germs pathogens, isolated for all samples, showed that the Enterobacter is the most common type (45%). However, other types have a lower rate such as: Klebsiella (30%), Buttiaux agrestis (5%), Serratia marcescens (10%) Escherichia Coli (10%). Finally, the strains, tested for sensitivity to the twelve types of antibiotics, have shown some resistance to ampicillin, amoxicillin, amoxicillin + Ac clavulanic, cefalotine, ticarcilline and co-trimoxazole

Zinc- and Copper-Doped Mesoporous Borate Bioactive Glasses: Promising Additives for Potential Use in Skin Wound Healing Applications

In this study, zinc (Zn)- and copper (Cu)-doped 13-93B3 borate mesoporous bioactive glasses (MBGs) were successfully synthesized using nitrate precursors in the presence of Pluronic P123. We benefited from computational approaches for predicting and confirming the experimental findings. The changes in the dynamic surface tension (SFT) of simulated body fluid (SBF) were investigated using the Du Noüy ring method to shed light on the mineralization process of hydroxyapatite (HAp) on the glass surface. The obtained MBGs were in a glassy state before incubation in SBF. The formation of an apatite-like layer on the SBF-incubated borate glasses was investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The incorporation of Zn and Cu into the basic composition of 13-93B3 glass led to changes in the glass transition temperature (Tg) (773 to 556 °C), particle size (373 to 64 nm), zeta potential (−12 to −26 mV), and specific surface area (SBET) (54 to 123 m2/g). Based on the K-means algorithm and chi-square automatic interaction detection (CHAID) tree, we found that the SFT of SBF is an important factor for the prediction and confirmation of the HAp mineralization process on the glasses. Furthermore, we proposed a simple calculation, based on SFT variation, to quantify the bioactivity of MBGs. The doped and dopant-free borate MBGs could enhance the proliferation of mouse fibroblast L929 cells at a concentration of 0.5 mg/mL. These glasses also induced very low hemolysis (<5%), confirming good compatibility with red blood cells. The results of the antibacterial test revealed that all the samples could significantly decrease the viability of Pseudomonas aeruginosa. In summary, we showed that Cu-/Zn-doped borate MBGs can be fabricated using a cost-effective method and also show promise for wound healing/skin tissue engineering applications, as especially supported by the cell test with fibroblasts, good compatibility with blood, and antibacterial properties

Genetic Variants of Cytochrome b-245, Alpha Polypeptide Gene and Premature Acute Myocardial Infarction Risk in An Iranian Population

Background: Oxidative stress induced by superoxide anion plays critical roles in the pathogenesis of coronary artery disease (CAD) and hence acute myocardial infarction (AMI). The major source of superoxide production in vascular smooth muscle and endothelial cells is the NADPH oxidase complex. An essential component of this complex is p22phox, that is encoded by the cytochrome b-245, alpha polypeptide (CYBA) gene. The aim of this study was to investigate the association of CYBA variants (rs1049255 and rs4673) and premature acute myocardial infarction risk in an Iranian population. Methods: The study population consisted of 158 patients under the age of 50 years, with a diagnosis of premature AMI, and 168 age-matched controls with normal coronary angiograms. Genotyping of the polymorphisms was performed by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP). Results: There was no association between the genotypes and allele frequencies of rs4673 polymorphism and premature acute myocardial infarction (P>0.05). A significant statistical association was observed between the genotypes distribution of rs1049255 polymorphism and AMI risk (P=0.037). Furthermore, the distribution of AA+AG/GG genotypes was found to be statistically significant between the two groups (P=0.011). Conclusions: Our findings indicated that rs1049255 but not rs4673 polymorphism is associated with premature AMI

New insights into electron spin dynamics in the presence of correlated noise

The changes of the spin depolarization length in zinc-blende semiconductors when an external component of correlated noise is added to a static driving electric field are analyzed for different values of field strength, noise amplitude and correlation time. Electron dynamics is simulated by a Monte Carlo procedure which keeps into account all the possible scattering phenomena of the hot electrons in the medium and includes the evolution of spin polarization. Spin depolarization is studied by examinating the decay of the initial spin polarization of the conduction electrons through the D'yakonov-Perel process, the only relevant relaxation mechanism in III-V crystals. Our results show that, for electric field amplitude lower than the Gunn field, the dephasing length shortens with the increasing of the noise intensity. Moreover, a nonmonotonic behavior of spin depolarization length with the noise correlation time is found, characterized by a maximum variation for values of noise correlation time comparable with the dephasing time. Instead, in high field conditions, we find that, critically depending on the noise correlation time, external fluctuations can positively affect the relaxation length. The influence of the inclusion of the electron-electron scattering mechanism is also shown and discussed.Comment: Published on "Journal of Physics: Condensed Matter" as "Fast Track Communications", 11 pages, 9 figure