Should friction losses be included in an electromechanical model of a bioinspired flapping-wing micro aerial vehicle to estimate the flight energetic requirements?

The paper aims to examine the effects of mechanical losses on the performance of a bioinspired flapping-wing micro aerial vehicle (FWMAV) and ways to mitigate them by introducing a novel electromechanical model. The mathematical model captures the effect of a DC gear motor, slider-crank, flapping-wings aerodynamics, and frictional losses. The aerodynamic loads are obtained using a quasi-steady flow model. The parameters of the flight mechanism are estimated using published experimental data which are also used to validate the mathematical model. Incorporating the flapping mechanism friction losses into the mathematical model enables capturing the physics of the problem with higher accuracy, which is not possible with simpler models. It also makes it possible to estimate the aerodynamic energetic requirements. Moreover, the model enabled evaluations of the effects of adding bioinspired elastic elements on the efficiency of the system. Although it is established through experimental studies that the addition of a bioinspired elastic element can improve system efficiency and increase lift generation, the existing mathematical models fail to model and predict such effects. It has been demonstrated that the addition of an elastic element can reduce friction losses in the system by decreasing the internal forces. Optimised parameters for a FWMAV incorporating elastic elements are also obtained.

Identification of nucleotide polymorphism within the NeuroD1 candidate gene and its association with type 1 diabetes susceptibility in Iranian people by polymerase chain reaction-restriction fragment length polymorphism.

Objectives Diabetes is a serious disease, and the number of affected individuals with diabetes is considerably high. The aim of this study is the identification of NeuroD1 Ala45Thr polymorphism and its association with type 1 diabetes susceptibility in Iranian people. Methods Clinical and biochemical characteristics for 146 people (76 diabetics and 70 nondiabetics) were measured, such as fasting blood sugar, triacylglycerol, total cholesterol, age, and weight in each individual. Polymerase chain reaction-restriction fragment length polymorphism technique (MwoI restriction-enzyme) was used for genotyping of the NeuroD1 Ala45Thr polymorphism. Results In this study, the frequency of the A allele in diabetic patients in comparison with the healthy control group had a significantly higher percentage (p < 0.01), whereas diabetic patients had the AA genotype, approximately four times more than the healthy control group (p < 0.01). In addition, we observed that fasting blood sugar had a higher concentration in the AA genotype than in AG + GG genotypes (p < 0.01). Conclusions The A allele may be a risk factor for the expansion of type 1 diabetes in the Iranian population. However, the NeuroD1 Ala45Thr polymorphism and its role in type 1 diabetes in different populations are controversial.

Effects of Ramadan Fasting on Serum Amyloid A and Protein Carbonyl Group Levels in Patients With Cardiovascular Diseases.

INTRODUCTION: Serum amyloid-A (SAA) and protein carbonyl group are rigorously related with cardiovascular diseases (CVDs) as a sensitive marker of an acute inflammatory state and as an important index of oxidative stress, respectively. Moreover, diet is one of the main factors that can modify cardiovascular risks. Therefore, this study aimed to investigate the effects of Ramadan fasting on SAA and protein carbonyl group levels in patients with CVDs. METHODS: Twenty-one patients (21 male; mean age 52±9 years old) with CVDs (coronary artery disease, cerebrovascular, or peripheral arterial diseases) were participated in this study. Biochemical parameters were measured in patients 2 days before and 2 days after Ramadan fasting. SAA levels were assessed using enzyme-linked immunosorbent assay and Cayman's protein carbonyl colorimetric assay was provided for measuring protein carbonyl groups. RESULTS: According to the findings of the study, post-Ramadan levels of inflammatory biomarker, SAA was decreased significantly in patients with CVDs in comparison with the baseline before-fasting values (16.84±8.20 vs. 24.40±6.72 µg/ml, P = 0.021). In addition, Ramadan fasting significantly reduced the levels of protein carbonyl group in patients as compared with those of baseline values (33.08±15.31 vs. 43.65±16.88 nmol/ml, P = 0.039). CONCLUSION: Ramadan fasting has impressive effects on modulating CVDs by decreasing inflammation and oxidative stress markers. However, to get a clear conclusion with more results, further investigation is warranted.

Protective Effects of Green Tea Extract against Hepatic Tissue Injury in Streptozotocin-Induced Diabetic Rats.

Although diabetic hepatopathy is potentially less common, it may be appropriate for addition to the list of target organ conditions related to diabetes. This study was designed to evaluate the hepatoprotective properties of green tea extract (GTE) in STZ-induced diabetes in rats. Wistar rats were made diabetic through single injection of STZ (75 mg/kg i.p.). The rats were randomly divided into four groups of 10 animals each: Group 1, healthy control; Group 2, nondiabetics treated with GTE administered orally (1.5%, w/v); Group 3, diabetics; Group 4, diabetics treated with GTE (1.5%, w/v) for 8 weeks. Serum biomarkers were assessed to determine hepatic injury. Malondialdehyde (MDA) and reduced glutathione (GSH) contents were measured to assess free radical activity in the liver tissue. Hepatic antioxidant activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) were also determined. The biochemical findings were matched with histopathological verifications. Liver MDA content and serum levels of ALT, AST, ALP, and bilirubin in Group 3 significantly increased compared to Group 1 (P < 0.05) and significantly decreased in Group 4 compared to Group 3 (P < 0.05). Serum albumin level and GSH, SOD, CAT, and GSH-Px contents of the liver in Group 3 were significantly decreased compared to Group 1 (P < 0.05) and were significantly increased in Group 4 compared to Group 3 (P < 0.05). Histopathologically, the changes were in the same direction with biochemical findings. This study proved the hepatoprotective activity of GTE in experimentally induced diabetic rats.

Interleukin-1 beta, interleukin-6 and TGF-beta in follicular tissue of impacted third molars.

The clinical evaluation and management of impacted third molars remain challenging. The aim of the present study was to investigate possible associations between follicular tissue cytokines and radiographic manifestations of impacted third molar. The population included 72 patients who underwent surgical extraction of impacted third molars. All these patients underwent a preliminary panoramic radiograph. Levels of interleukin-1 beta (IL-1ß), interleukin-6 (IL-6) and transforming growth factor beta (TGF-ß) in tissue extracts were determined using ELISA. There were no significant differences between bony and tissue impaction as regards IL-1ß, IL-6 and TGF-ß levels. Moreover, the same results were obtained as far as the amount of pericoronal space and the presence or absence of a history of pericoronitis are concerned. These results suggest that radiographic findings or a history of pericoronitis are not associated with levels of expression of pro-inflammatory cytokines in patients undergoing surgical removal of impacted third molars. However, further studies are needed to address the possibility of variability during disease progression.

C-reactive protein, fibrinogen, lipoprotein (a), and lipid profile levels and platelet counts in ischemic stroke patients.

OBJECTIVE: To ascertain the most prevalent risk factor for stroke. METHODS: We performed a descriptive and analytical prospective study on patients with stroke admitted to the neurology wards of Imam Hospital, Tabriz, Iran during 2004 and 2005. The study comprised 100 ischemic stroke (IS) patients consisting of 46 men and 54 women with a mean age of 67 +/- 15, and 100 age and gender matched apparently healthy subjects. Plasma levels of C-Reactive protein (CRP), fibrinogen, platelet counts, lipoprotein (a) (LP (a)), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), total cholesterol (TC), and triglycerides (TG) were measured in both patients and controls. Background disease was also investigated in the patients. Hemorrhagic and embolic stroke patients were excluded from the study. RESULTS: We found no significant difference in serum fibrinogen, HDL-c levels, and platelet counts between patients and control subjects, however, levels of LP (a), TG, LDH-c, and CRP were significantly higher in patients than controls. Among the predisposing background illnesses, the most common risk factors were hypertension and hyperlipidemia. The frequency of studied risk factors among patients was: no risk factors (20%), one risk factor (32%), 2 risk factors (36%), and 3 risk factors (12%). CONCLUSION: Hypertension was the most prevalent background disease in IS patients. We also found that although there is close relationship in the incidence of IS with levels of LP (a), TC, TG, LDL-c, and CRP, the cutoff point frequency of fibrinogen, CRP, LP (a), and platelet counts was variable from patient to patient.