Dependence of chaotic behavior on optical properties and electrostatic effects in double beam torsional Casimir actuation

We investigate the influence of Casimir and electrostatic torques on double beam torsional microelectromechanical systems with materials covering a broad range of conductivities of more than three orders of magnitude. For the frictionless autonomous systems, bifurcation and phase space analysis shows that there is a significant difference between stable and unstable operating regimes for equal and unequal applied voltages on both sides of the double torsional system giving rise to heteroclinic and homoclinic orbits, respectively. For equal applied voltages, only the position of a symmetric unstable saddle equilibrium point is dependent on the material optical properties and electrostatic effects, while in any other case there are stable and unstable equilibrium points are dependent on both factors. For the periodically driven system, a Melnikov function approach is used to show the presence of chaotic motion rendering predictions of whether stiction or stable actuation will take place over long times impossible. Chaotic behavior introduces significant risk for stiction, and it is more prominent to occur for the more conductive systems that experience stronger Casimir forces and torques. Indeed, when unequal voltages are applied, the sensitive dependence of chaotic motion on electrostatics is more pronounced for the highest conductivity systems.Comment: 24 pages, 11 figure

Screening Level Evaluation of the Potential Influence of Proposed Surface-Water Withdrawals on Groundwater Discharge into the St. Johns River

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Buckling analysis of a non-concentric double-walled carbon nanotube

On the basis of a theoretical study, this research incorporates an eccentricity into a system of compressed double-walled carbon nanotubes (DWCNTs). In order to formulate the stability equations, a kinematic displacement with reference to the classical beam hypothesis is utilized. Furthermore, the influence of nanoscale size is taken into account with regard to the nonlocal approach of strain gradient, and the van der Waals interaction for both inner and outer tubes is also considered based on the Lennard–Jones model. Galerkin decomposition is employed to numerically deal with the governing equations. It is evidently demonstrated that the geometrical eccentricity remarkably affects the stability threshold and its impact is to increase the static stability of DWCNTs

Change in bone mineral density in post menopausal women with rheumatoid arthritis

Introduction: Low bone mass is a serious complication of post menopausal women with rheumatoid arthritis. We determined the Change in Bone Mineral Density in postmenopausal women with rheumatoid arthritis. Methods: This retrospective cohort study was carried out on consecutive postmenopausal women with rheumatoid arthritis who were referred to the Azar 5th teaching hospital affiliated to Golestan University of Medical Sciences, North of Iran in 2009. The required data were gathered from the patients' medical records. The data were analyzed using SPSS software and statistical tests. Results: We studied 98 postmenopausal women with rheumatoid arthritis. Mean number of years since menopause and mean duration of disease were 9.39 and 5.13 respectively. T Score mean in femoral neck and lumbar spines was -1.45±1.26 and -2.45±1.44 respectively. The overall prevalence of osteoporosis at both the lumbar spine and femoral neck was 13.3. We have found a significant correlation between age, duration of disease, duration of menopause and bone mineral density (P-Value<0.01). Conlusion: Our results indicate a negative effect of age, number of years since menopause and duration of disease on bone mineral density. So, BMD should be measured in high risk women prior to the implementation of any treatment or prevention program

A review on promising natural agents effective on hyperlipidemia.

Hyperlipidemia is a prevalent disease and a major component of the metabolic syndrome resulting from various factors. This disease increases morbidity and mortality when combined with other prevalent diseases such as diabetes mellitus, hypertension, and cardiovascular diseases. The side effects of the current lipid-lowering drugs have increased the tendency to move toward traditional and alternative treatments. Epidemiological observations indicate that using alternative treatments, consumption of medicinal plants, diet, and consumption of fruits have had satisfactory results on the effects of hyperlipidemia in many societies. It should be noted that in majority of societies, even developed countries, the tendency toward eating lipid-lowering medicinal plants has increased extensively. Using these plants especially when common remedies cannot control the disease is significant. Although consumption of medicinal plants by hyperlipidemic patients may show improvement in disease state, drug interaction and side effects may cause complications in disease control. Therefore, in this review, apart from introducing some of the reliable plants effective in inhibition and decrease of hyperlipidemia, the possibility of their intoxication and drug interaction is also presented

Surgical repair of Tetralogy of Fallot following primary palliation: Right ventricular outflow track stenting versus modified Blalock-Taussig shunt

Background: Tetralogy of Fallot (TOF) is a cyanotic disease requiring early intervention. We assessed the effect of right ventricular outflow tract (RVOT) stenting versus modified Blalock-Taussig shunt (mBTS) on outcomes of surgical repair of TOF. Methods: Fifteen palliated TOF infants underwent complete repair surgery. RVOT stenting was performed in seven infants and mBTS was done in eight infants. Data on sequential patients who underwent surgery were collected and reviewed retrospectively. Results: Stenting group were significantly younger (1.62 ± 0.34 vs 2.80 ± 0.52, p = 0.001), had lower body weight (3.28 ± 0.48 vs 5.03 ± 0.67, p = 0.001) and lesser body surface area (0.20 ± 0.01 vs 0.26 ± 0.20, p = 0.001) than the mBTS group at palliation. Mean right pulmonary artery (RPA) diameter in stenting group at palliation was 2.9 ± 0.54 mm (z-score -3.08 ± 0.97) and increased at surgery to 4.6 ± 0.49 mm (z-score �0.79 ± 0.66) (p = 0.001). The mean left pulmonary artery (LPA) diameter was 2.5 ± 0.42 mm (z-score -3.3 ± 0.86), which increased to 3.3 ± 0.40 mm (z-score -2.2 ± 0.74) at surgery (p = 0.005). The mean RPA diameter in mBTS group at palliation was 3.2 ± 0.32 mm (z-score �2.9 ± 0.70) and increased at surgery to 4.3 ± 0.55 mm (z-score �1.1 ± 0.94) (p = 0.001). The mean LPA diameter was 2.8 ± 0.26 mm (z-score -3.3 ± 0.62), which increased to 3.2 ± 0.24 mm (z-score �2.4 ± 0.52) at surgery (p = 0.032). Repeat echocardiography showed significant increase in McGoon ratio and Nakata index in both groups (p = 0.001). No significant differences were seen between the two groups regarding surgical procedure and postoperative complications. Conclusion: RVOT stenting is a safe and effective approach instead of mBTS in hazardous TOF infants with hypercyanotic spell, small PAs and complex anatomies. © 201

Surgical repair of Tetralogy of Fallot following primary palliation: Right ventricular outflow track stenting versus modified Blalock-Taussig shunt

Background: Tetralogy of Fallot (TOF) is a cyanotic disease requiring early intervention. We assessed the effect of right ventricular outflow tract (RVOT) stenting versus modified Blalock-Taussig shunt (mBTS) on outcomes of surgical repair of TOF. Methods: Fifteen palliated TOF infants underwent complete repair surgery. RVOT stenting was performed in seven infants and mBTS was done in eight infants. Data on sequential patients who underwent surgery were collected and reviewed retrospectively. Results: Stenting group were significantly younger (1.62 ± 0.34 vs 2.80 ± 0.52, p = 0.001), had lower body weight (3.28 ± 0.48 vs 5.03 ± 0.67, p = 0.001) and lesser body surface area (0.20 ± 0.01 vs 0.26 ± 0.20, p = 0.001) than the mBTS group at palliation. Mean right pulmonary artery (RPA) diameter in stenting group at palliation was 2.9 ± 0.54 mm (z-score -3.08 ± 0.97) and increased at surgery to 4.6 ± 0.49 mm (z-score �0.79 ± 0.66) (p = 0.001). The mean left pulmonary artery (LPA) diameter was 2.5 ± 0.42 mm (z-score -3.3 ± 0.86), which increased to 3.3 ± 0.40 mm (z-score -2.2 ± 0.74) at surgery (p = 0.005). The mean RPA diameter in mBTS group at palliation was 3.2 ± 0.32 mm (z-score �2.9 ± 0.70) and increased at surgery to 4.3 ± 0.55 mm (z-score �1.1 ± 0.94) (p = 0.001). The mean LPA diameter was 2.8 ± 0.26 mm (z-score -3.3 ± 0.62), which increased to 3.2 ± 0.24 mm (z-score �2.4 ± 0.52) at surgery (p = 0.032). Repeat echocardiography showed significant increase in McGoon ratio and Nakata index in both groups (p = 0.001). No significant differences were seen between the two groups regarding surgical procedure and postoperative complications. Conclusion: RVOT stenting is a safe and effective approach instead of mBTS in hazardous TOF infants with hypercyanotic spell, small PAs and complex anatomies. © 201