Stress intensity factors of a central slant crack with frictional surfaces in plates with biaxial loading

The stress intensity factor is a traditional topic in mechanics and there have been many solutions for many different cases. The closed frictional crack problem has been modeled in the rock mechanics field where fractures are mostly under compression. Further, the effect of finite plate dimensions under biaxial loading has not been considered in the literature. The key contribution of the present paper is to evaluate the effect of the crack length to plate width ratio on the mode I and II stress intensity factors (SIF) of a central slant crack with frictional surfaces in plates with biaxial loading of different patterns, i.e. tension-tension, tension-compression, compression-tension or compression-compression. A plane strain elastic two-dimensional finite element analysis was adopted. Crack length to plate width ratios equal to 0.1, 0.3 and 0.5 with biaxial ratios from –1 to 1, crack angles from 0° to 90° and friction coefficients from 0 to 1 were considered. Contact regimes and the effect of the crack length to plate width ratio were found dependent on biaxial ratio and pattern, friction coefficient and crack angle.     

The immunogenic effect of purified antigens of B. alexandrina against Schistosoma mansoni in experimental animals (I) as measured by worm load and viability of ova

Current stratigies for the control of schistosomiasis are based primarily on chemotherapy but successful vaccination against infection has been also demonstrated in several host parasite models. In this study, the immunogenic effect of two purified antigens (Fiv 20-29 000 daltons & Fv 20-24 000 daltons) extracted from non infected hepatopancreas of B. alexandrina as measured by worm load, state of copulation and viability of ova in tissues. The antigens were prepared using gel filtration chromatography and their molecular weights were estimated through sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). Four dilutions from each antigen were prepared and injected in two groups (33 each) of Swiss albino mice at weekly intervals. A control group was injected with phosphate buffer saline (PBS) in the same manner. All mice were injected with 100 cercariae using immersion method. Sacrification was done regularly after 7 weeks of injection. On the basis of worm load, Fiv gave protection of 44% while Fv gave only 36%. The number of worms in copula was significantly reduced and they became delicate, fragile, stunted and malformed. Both antigens gave a significant reduction in total viable eggs in tissues.     

Factors affecting C3 in intestinal schistosomiasis

Complement component C3 was investigated in sera of a group of schistosomal patients free from obvious nephritis. C3 was studied in relation to S. mansoni egg count, presence of HBsAg, and liver functions. C3 level was low in schistosomal patients than normal individuals. Levels were low in both HBsAg --ve and HBsAG +ve schistosomal patients. No significant difference was found between HBsAg --ve and HBsAg +ve in one hand, and between patients with egg counts more than 400 and those with egg counts less than 400 eggs/1 gr as regards level of C3 on the other hand. Presence of ascites did not affect C3 concentration. Positive correlation was found with Serum albumin, but not with prothrombin concentration serum alkaline phosphatase or serum transaminases.     

EQOWSN: Evolutionary-based query optimization over self-organized wireless sensor networks

In this paper, a new approach has been introduced that integrates an evolutionary-based mechanism with a distributed query sensor cover algorithm for optimal query execution in self-organized wireless sensor networks (WSN). An algorithm based on an evolutionary technique is proposed, with problem-specific genetic operators to improve computing efficiency. Redundancy within a sensor network can be exploited to reduce the communication cost incurred in execution of spatial queries. Any reduction in communication cost would result in an efficient use of battery energy, which is very limited in sensors. Our objective is to self-organize the network, in response to a query, into a topology that involves an optimal subset of sensors that is sufficient to process the query subject to connectivity, coverage, energy consumption, cover size and communication overhead constraints. Query processing must incorporate energy awareness into the system by reducing the total energy consumption and hence increasing the lifetime of the sensor cover, which is beneficial for large long running queries. Experiments have been carried out on networks with different sensors Transmission radius, different query sizes, and different network configurations. Through extensive simulations, we have shown that our designed technique result in substantial energy savings in a sensor network. Compared with other techniques, the results demonstrated a significant improvement of the proposed technique in terms of energy-efficient query cover with lower communication cost and lower size.     

双轴对称薄壁锥形柱轴心受压的极限承载力

薄壁工字型锥形构件的性能由构件长细比和板单元宽厚比决定。本文对这种交互效应进行了理论研究。构建了一个具有几何非线性的非线性有限元模型进行计算。选取了大量具有不同宽厚比的翼缘和腹板,以及具有不同长细比的构件进行研究,归纳出较完整的极限强度-长细比曲线,和不同的破坏模式。根据设计目的得出一系列的曲线。最后,提出了锥形细长工字型构件(整个截面)的轴心极限承载力经验公式。这个方程简化了有效宽度的计算,提供更灵活的设计方法。     

Androgen Receptor Antagonists and Anti-Prostate Cancer Activities of Some Newly Synthesized Substituted Fused Pyrazolo-, Triazolo- and Thiazolo-Pyrimidine Derivatives

A series of substituted pyrazole, triazole and thiazole derivatives (2–13) were synthesized from 1-(naphtho[1,2-d]thiazol-2-yl)hydrazine as starting material and evaluated as androgen receptor antagonists and anti-prostate cancer agents. The newly synthesized compounds showed potent androgen receptor antagonists and anti-prostate cancer activities with low toxicity (lethal dose 50 (LD₅₀)) comparable to Bicalutamide as reference drug. The structures of newly synthesized compounds were confirmed by IR, ¹H-NMR, ¹³C-NMR, and MS spectral data and elemental analysis. The detailed synthesis, spectroscopic data, LD₅₀ values and pharmacological activities of the synthesized compounds are reported.     

Syringomyelia due to arachnoiditis. Clinical-radiological description of 5 patients

Five patients (mean age 44 years--range 21-67 years) with arachnoiditis of different origin who posteriorly developed syringomyelia are presented. The etiopathogenic mechanism of the arachnoiditis was post injury in one case, 2 patients had history of meningitis (tuberculous and pneumococcic) and in the other two no related factor was found. The period of latency among the causes which originated arachnoiditis and the diagnosis of syringomyelia oscillated between 10 months and 16 years. The localization of the cavity was dorsal in 3 cases, cervical in another and in the last it was extended along the whole spine. No patient demonstrated the Arnold-Chiari malformation nor basilar impression. Analyzing the clinical history, radiologic studies and surgical findings the most probable etiopathogenic mechanism involved in each case is discussed.     

A Low-Voltage Low-Power CMOS Analog Adaptive Equalizer for UTP-5 Cables

An analog adaptive equalizer based on a feed-forward architecture is implemented in 0.18-mum digital CMOS process. The equalizer is implemented with only digital core devices and operates at 125 Mbps over unshielded-twisted-pair category-5 cable of up to 100 m. Novel low-power circuit and system techniques resulted in 3.7-mW total power consumption and supply voltage operation as low as 1.6 V. The maximum peak-to-peak jitter at the output of the equalizer (including the transmit path driver) under all cable length is 0.33 UI. The total area of the equalizer is 27738 mum².