Electrocatalytic reduction of NO2: Platinum modified glassy carbon electrode

Platinum particles were electrochemically deposited over glassy carbon (GC) to prepare GC-Pt electrodes. The electrocatalytic behaviors of this electrode have been compared with that of an ordinary polycrystalline(OPC) Pt and GC electrode in reducing NO₂⁻ at neutral medium. The as prepared GC-Pt electrode reduced NO₂⁻, exhibiting double-peak reduction waves. The reduction performance of this electrode was noticed at least 7.8 times higher than that of an OPC Pt electrode. The sensitivity of the GC-Pt electrode was found to be enhanced by the temperature rise. A consecutive mechanism, NO₂⁻ → NO → NH₄⁺, over the as prepared GC-Pt electrode has been investigated.     

The Method of Fundamental Solutions applied to 3D structures with body forces using particular solutions

This paper presents the Method of Fundamental Solutions for three-dimensional elastostatics with body forces. The gravitational body loading is considered as an example for the treated body forces. A new set of particular solutions corresponding to such loading is derived using Hörmander operator-decoupling technique, and the relevant particular solution expressions for displacements, tractions and stresses are derived and given explicitly. Several examples are tested and the results confirm the validity and efficiency of the presented method.     

Effects of Ramadan fasting on cardiovascular risk factors: a prospective observational study

ABSTRACT: BACKGROUND: Previous research has shown that Ramadan fasting has beneficial effects on cardiovascular risk factors, however there are controversies. In the present study, the effect of Ramadan fasting on cardiovascular risk factors has been investigated. METHOD: This is a prospective observational study that was carried out in a group of patients with at least one cardiovascular risk factor (including history of documented previous history of either coronary artery disease (CAD), metabolic syndrome or cerebro-vascular disease in past 10 y). Eighty two volunteers including 38 male and 44 female, aged 29--70 y, mean 54.0 [PLUS-MINUS SIGN] 10 y, with a previous history of either coronary artery disease, metabolic syndrome or cerebro-vascular disease were recruited. Subjects attended the metabolic unit after at least 10 h fasting, before and after Ramadan who were been fasting for at least 10 days. A fasting blood sample was obtained, blood pressure was measured and body mass index (BMI) was calculated. Lipids profile, fasting blood sugar (FBS) and insulin, homocysteine (hcy), high-sensitivity C-reactive protein (hs-CRP) and complete blood count (CBC) were analyzed on all blood samples. RESULTS: A significant improvement in 10 years coronary heart disease risk (based on Framingham risk score) was found (13.0 [PLUS-MINUS SIGN] 8 before Ramadan and 10.8 [PLUS-MINUS SIGN]7 after Ramadan, P <0.001, t test).There was a significant higher HDL-c, WBC, RBC and platelet count (PLT), and lower plasma cholesterol, triglycerides, LDL-c, VLDL-c, systolic blood pressure, body mass index and waist circumference after Ramadan (P <0.05, t test). The changes in FBS, insulin,Homeostasis Model Assessment Insulin Resistance (HOMA-IR), hcy, hs-CRP and diastolic blood pressure before and after Ramadan were not significant (P >0.05, t test). CONCLUSIONS: This study shows a significant improvement in 10 years coronary heart disease risk score and other cardiovascular risk factors such as lipids profile, systolic blood pressure, weight, BMI and waist circumference in subjects with a previous history of cardiovascular disease.     

Synthesis of High Magnetoelectric Coefficient Composites Using Annealing and Aging Route

In this paper, aging temperature and time dependence of ferroelectric, ferromagnetic, and magnetoelectric properties of lead zirconate titanate and nickel ferrite composite (1– x ) Pb(Zr_0.52Ti_0.48)O₃– x NiFe_1.9Mn_0.1O₄ (PZT–NFM, x =0.03, 0.05, 0.1) are reported. The magnetoelectric composites of different compositions were fabricated by using a process based on the controlled precipitation route. The processing is a combination of conventional mixed oxide sintering and thermal treatment. The thermal treatment consists of annealing at a high temperature (800°C for 10 h), followed by aging in the range of 300–400°C for 3–15 h. X-ray diffractometry patterns show variation in the amount of spinel phase with different aging temperature and time. Scanning electron microscopy investigation showed that the annealing and aging treatment increases the homogeneity of NFM in the PZT matrix. The magnitude of piezoelectric constant ( d ₃₃), piezoelectric voltage constant ( g ₃₃), and the dielectric constant exhibited significant variation in magnitude with aging time and temperature. Aging at 400°C for 5 h exhibited a maximum magnitude of d ₃₃ and g ₃₃ and minimum magnitude of dielectric constant. The magnitude of the magnetoelectric (ME) voltage coefficient (d E /d H ) for 0.9PZT–0.1NFM samples sintered at 1125 °C was found to be of the order of 78 mV/cm Oe. This magnitude increased to 140 mV/cm Oe after annealing and aging at 300°C for 5 h. This significant enhancement in the magnetoelectric coefficient is probably due to the homogenization and precipitation of the spinel (NFM) phase in the perovskite matrix.     

High efficiency wireless optical links in high transmission speed wireless optical communication networks

Power link budgets are prepared for wireless optical communication systems to illustrate the optical losses that happen during transmission. This paper has presented optical wireless links, which offer ultra multi gigabit per second data rates and low system complexity. For ground space and/or terrestrial communication systems, these links suffer from atmospheric loss mainly due to fog, and scintillation. Optical wireless links provide high bandwidth solution to the last mile access bottleneck. However, an appreciable availability of the link is always a concern. Wireless optical links are highly weather dependent, and fog is the major attenuating factor reducing the link availability. Link margin, received signal power, transmission bit rate, bit rate distance product, signal‐to‐noise ratio, and BER are the major interesting design parameters in the current study. Copyright © 2013 John Wiley & Sons, Ltd.     

Optical Network Management and Its Performance Evaluation for Both Future Cost Planning and Triple Play Solutions

This paper has presented the wavelength division multiplexing technology is being extensively deployed on point to point links within transport networks in the Egypt. Our suggested Trans-Egypt Network which uses optical cross connects to route lightpaths through the network are referred to as wavelength routing networks. The average setup time, average link utilization, traffic load, blocking probability, network costs, and network throughput with triple play solutions and achievable link utilization for multi math routing in the presence and absence of wavelength conversions are the major interesting parameters in the design of network topology under different routing and wavelength assignment such as first fit, random, least used and most used in order to upgrade network performance and its transmission efficiency.     

Magnetoelectric properties of microwave sintered particulate composites

This study reports the results on three different particulate composites synthesized using conventional sintering, microwave sintering under magnetic field, and microwave sintering under electric field. The results show that magnetoelectric coefficient in the case of samples synthesized using microwave approach yields the same magnitudes as that of conventional sintering. The process of microwave sintering is rapid and significantly reduces the time and energy required for synthesizing composites as compared to conventional sintering.     

Role of Mycoplasma pneumoniae in acute respiratory-tract infections in Saudi paediatric patients

The expression of RB and bcl-2 proteins was investigated in 135 thyroid carcinomas (130 papillary carcinomas and five follicular carcinomas) by the immunohistochemical technique with RB and bcl-2 monoclonal antibodies. The results were as follows: 1) RB protein nuclear staining was shown in 117 of the 135 thyroid carcinomas (87%). Bcl-2 protein staining was shown in 82 of the carcinomas (61%). 2) There was a higher incidence of recurrence in RB-negative cases than in RB-positive cases (chi 2 test p = 0.001). But there is no significant relationship between the incidence of recurrence and the results of bcl-2 staining (chi 2 test p = 0.287). 3) The expression of RB protein was related to age and clinical N and M categories. Bcl-2 protein expression was related to clinical T categories. 4) The 10-year overall survival rate for RB-positive patients was higher than that for negative patients (long-rank test p < 0.0001). But the survival rate was not associated with bcl-2 expression (log-rank test p = 0.3). Our results suggest that assessment of RB protein expression by the immunohistochemical technique may be useful to determine the possibility of recurrence and to predict the outcome of thyroid carcinomas. We think that assessment of RB protein expression by the immunohistochemical technique can be applied as a more sensitive prognostic factor.