PPUAS--photopeak unfolding and self-shielding program

Computer code was developed to determine radioactive emission rates of nuclear fuels. Code is basically written for two different source geometries; however, unfolding routine can be executed for other source geometries

A novel method for incorporation of micron-sized SiC particles into molten pure aluminum utilizing a Co coating

Ceramic particles typically do not have sufficiently high wettability by molten metal for effective bonding during metal matrix composite fabrication. In this study, a novel method has been used to overcome this drawback. Micron-sized SiC particles were coated by a cobalt metallic layer using an electroless deposition method. A layer of cobalt on the SiC particles was produced prior to incorporation in molten pure aluminum in order to improve the injected particle bonding with the matrix. For comparison, magnesium was added to the melt in separate experiments as a wetting agent to assess which method was more effective for particle incorporation. It was found that both of these methods were more effective as regard ceramic particulate incorporation compared with samples produced with as-received SiC particles injected into the pure aluminum matrix. SEM images indicated that cobalt coating of the particles was more effective than magnesium for incorporation of fine SiC particles (below 30 lm), while totally the incorporation percentage of the particles was higher for a sample in which Mg was added as a wetting agent. In addition, microhardness tests revealed that the cobalt coating leads to the fabrication of a harder composite due to increased amount of ceramic incorporation, ceramic-matrix bonding, and possibly also to formation of Al-Co intermetallic phases

Effect of interfacial-active elements addition on the incorporation of micron-sized SiC particles in molten pure aluminum

Ceramic particles generally have poor wettability by liquid metal, leading to a major drawback in fabrication of cast metal matrix composites (MMCs). In this work, the effect of 1 wt. % of Ca, Mg, Si, Ti, Zn and Zr interfacial-active alloying elements was studied on the incorporation of micron-sized SiC particles into the molten pure aluminum using the vortex casting method at 680 1C. The results indicated that Ti, Zr, Zn and Si were not positively effective in improving particulate incorporation, while Ca and especially Mg were very efficient at increasing the incorporation of ceramic particles into the molten Al. Also, it was revealed that Al3Ti, and Al3Zr intermetallic phases were formed for samples containing Ti and Zr, making hybrid MMCs with a higher amount of hardness. Finally, it was found that a reaction layer between Al and SiC particles was formed at the Al/SiC interface for all of the samples, expect for the ones containing Si and Ti, indicating that for most of the samples at 680 1C an exothermic reaction took place between the Al and SiC particles

Antiviral activity of Holothuria sp. a sea cucumber against herpes simplex virus type 1 (HSV-1)

BACKGROUND: Finding the new bioactive compounds with antiviral activity from the natural resources are in interest of many drug discovery scientists. Sea cucumber is among the marine organisms a traditional food item in Asia with different applications in traditional medicine. METHODS: In current study, a cold water extract of the Holothuria sp, one type Persian Gulf’s sea cucumber was evaluated for its antiviral effects against KOS strain of Herpes Simplex Virus tyoe 1 (HSV-1) in cell culture. The half maximal inhibitory concentration (IC50) values were calculated for anti-adsorption activity and intracellular antiviral activity of the crude extract separately. RESULTS: The extract exhibited antiviral activity not only against the virus adsorption to the cells, but also on virus intracellular replication.The CC50 for sea cucumber extract was 32.57 mg/ml. The IC50 values for the inhibition of the virus adsorption to the cells and virus intracellular replication were 120.2 and 189.9 μg/ml respectively. Selectivity index (SI) value for anti-adsorption activity was 189 while that value for the extract’s intracellular antiviral activity was 172. CONCLUSIONS: The results showed that Holothuria sp, water extract has remarkable antiviral effect against HSV-1 in cell culture and it is crucial to investigate the mechanism(s) of action of extract. Moreover, identification of the effective compound(s) within the extract would be necessary for future studies towards developing the new natural antiviral agent against HSV-1

Acoustic surface wave generation over rigid cylinder arrays on a rigid plane

Propagation of an airborne acoustic pulse from a point source above an array of regularly spaced rigid cylinders on a rigid plane has been investigated using a two-dimensional multiple scattering theory. Time domain simulations show a main arrival and a separate delayed “tail.” Fourier analysis of the tail shows that, for a sufficiently sparse array of cylinders, it is composed of a series of spectral peaks resulting from constructive interference consistent with Bragg diffraction theory and amplitudes depending on the spacing and size of the cylinders. For increasingly compact distributions of cylinders, the lowest frequency peak is dominated by a quarter wavelength “organ pipe” or “gap” resonance in the space between the cylinders. Simulated pressure maps show that there is a transition region in the acoustic field with an extent that depends on the spacing and size of the cylinders. Beyond this region, individual gap resonances combine to create a field that declines exponentially with height, consistent with the behaviour of a surface wave. Data from measurements of acoustic pulses above copper cylinders on rigid fibreboard under anechoic conditions demonstrate some of the predicted characteristics

When defining boundaries for nexus analysis, let the data speak

A policy and research agenda has emerged in recent years to understand the interconnected risks natural resource systems face and drive. The so-called ‘Food-Energy-Water’ (FEW) nexus has served as a focal point for the conceptual, theoretical and empirical development of this agenda. This special issue provides an opportunity to reflect on whether natural resource use, as viewed through the FEW-nexus lens, provides a useful basis for guiding integrated environmental management. Within this piece, we describe how the partiality of the FEW-nexus overlooks major pathways of resource use (i) within the food system and (ii) across the wider burden of human activity. As a result, we argue FEW-centric analysis is more likely to disguise rather than reveal key opportunities for integrated environmental management.Cambridge Trust (Vice-Chancellor's Award

A pseudoclass-AB telescopic-cascode operational amplifier

ABSTRACT A novel class-AB architecture for single-stage operational amplifiers is presented. The structure employs a switchedcapacitor level shifter to provide a signal-dependent current in the current source of the common-source amplifier. Applying this pseudo-class-AB approach to a telescopic-cascode op-amp enhances the effective values of the slew rate and the transconductance and thus the op-amp speed

Genotyping and phylogenetic analysis of hydatid cysts isolated from livestock in Bushehr province, Iran

Hydatid cyst is one of the parasitic zoonoses caused by infection with the larval stage of Echinococcus granulosus tapeworm. The spread of this parasite is global and is of great importance in terms of public health. To date, ten different species of this parasite have been identified that differ in characteristics such as life cycle, epidemiology and pathogenesis. The purpose of this study was to determine the genotype and phylogenetic relationship of hydatid cysts isolated from livestock of Bushehr province, Iran. About 62 samples of hepatic and pulmonary hydatid cysts were collected from slaughtered animals. DNA extracted by phenol–chloroform method was amplified by PCR using primers specific for the cox1 gene. The PCR products of 50 samples were sequenced and analyzed using BioEdit software and compared with sequences in the GenBank. The phylogenetic tree was drawn using Neighbor Joining tree-NJ method, and its reliability was evaluated. Sequencing results showed that out of 50 sequenced samples, 43 samples had the genotype of Echinococcus granulosus and 7 samples had the genotype of Taenia hydatigena. By drawing a phylogenetic tree, all 43 hydatid cyst samples belonged to G1 strain. The predominance of G1 strain of hydatid cyst in livestock of Bushehr province shows the main role of this genotype in establishing the life cycle of parasite in this region and if the genotype of the parasite in dogs and humans is determined, then these findings can be used to disrupt the life cycle of the parasite and reduce the human infections

Scattering by coupled resonating elements in air

Scattering by (a) a single composite scatterer consisting of a concentric arrangement of an outer N-slit rigid cylinder and an inner cylinder which is either rigid or in the form of a thin elastic shell and (b) by a finite periodic array of these scatterers in air has been investigated analytically and through laboratory experiments. The composite scatterer forms a system of coupled resonators and gives rise to multiple low-frequency resonances. The corresponding analytical model employs polar angle dependent boundary conditions on the surface of the N-slit cylinder. The solution inside the slits assumes plane waves. It is shown also that in the low-frequency range the N-slit rigid cylinder can be replaced by an equivalent fluid layer. Further approximations suggest a simple square root dependence of the resonant frequencies on the number of slits and this is confirmed by data. The observed resonant phenomena are associated with Helmholtz-like behaviour of the resonator for which the radius and width of the openings are much smaller than the wavelength. The problem of scattering by a finite periodic array of such coupled resonators in air is solved using multiple scattering techniques. The resulting model predicts band-gap effects resulting from the resonances of the individual composite scatterers below the first Bragg frequency. Predictions and data confirm that use of coupled resonators results in substantial insertion loss peaks related to the resonances within the concentric configuration. In addition, for both scattering problems experimental data, predictions of the analytical approach and predictions of the equivalent fluid layer approximations are compared in the low-frequency interval

dy of P53 gene mutations in promoter and exons 2-4 and 9-11 in patient with gastric cancer by PCR-SSCP in Chaharmahal Va Bakhtiari province

Background: Gastric cancer is one of the most important diseases and after lung cancer, is the second cause of cancer death worldwide. Genetic factors including oncogenes and tumor suppressor genes are always contributed in progression of this cancer. The P53 tumor suppressor gene has a broad role in genomic stability and DNA repair. The aim of this study was to determine the P53 gene mutations in gastric cancer specimens in Chaharmahal Va Bakhtiari Province. Methods: In this descriptive-lab based study, we investigated the promoter, exons 2-4 and 9-11 of P53 gene mutations in 38 paraffin embedded gastric cancer specimens. DNA was extracted following the standard phenol chloroform protocol. The P53 gene mutations were determined using PCR-SSCP procedure. Results: Our study revealed no P53 gene mutation in promoter and exons 2-4 and 9-11 in the gastric cancer subjects studied. Conclusion: While P53 gene mutations have been reported as the most frequent genetic alterations and are found in about 50% of the human malignancies, no mutation was detected in this study. The reason may be due to small sample size or mutations on other genes or epigenetic factors