Structure and ultrasonic properties of vanadium tellurite glasses containing cupper oxide

The elastic properties of vanadium tellurite (65TeO2-(35-x) V2O5- xCuO) glasses with different compositions of cupper (x= 7.5 to 17.5 mol% in steps of 2.5 mol %) have been studied at room temperature (300K). The ultrasonic velocity measurements have been made using a transducer having resonating frequency of 4 MHz (both longitudinal and shear). The density, molar volume, and ultrasonic velocities show an interesting observations, which are used to explore the structural changes in the network. Elastic moduli, Poisson ratio, crosslink density, microhardnes, and Debye temperature of the glasses have been determined using the experimental data. The composition dependence of the elastic properties explores useful information about the physical properties of the vanadium tellurite glasses doped with cupper. Quantitative analysis has been carried out in order to obtain more informations about the structure of the glass under the study, based on bond compression model, and ring deformation model, i.e., the cation-anion bond of each oxide. The observed results through ultrasonic non-destructive evaluation investigate the structural changes and mechanical properties of the glass.

Fatal hemorrhagic intracranial TB in a renal transplant recipient despite INH prophylaxis

A 50-year-old ESRD who received LUR renal graft abroad. Since transplanted, he remained dependent on hemodialysis. The patient received steroid pulse therapy twice for rejecrion. Nonspecific bilateral lung infiltrate were noted on admission CXR, which stimulated the search for TB. The patient suddenly lost consciousness during his hospital stay. Intracranial hemorrhage was drained and tissue staining revealed heavy loads of tuberculus (TB) bacilli. The patient died two weeks later from septic shock with multi-organ failure.

Ultrasonic studies on polystyrene/styrene butadiene rubber polymer blends filled with glass fiber and talc

The compatibility of solid blends: PS/SBR, PS/SBR filled with glass fiber and PS/SBR filled with talc were studied using ultrasonic pulse echo technique. Measurements were carried out at room temperature (298 K) and a frequency of 3 MHz. The ultrasonic velocity for the compressional wave and that for shear wave have been measured to obtain the elastic moduli data by knowing of density. The variation of ultrasonic wave velocities and elastic moduli with weight percent of the blend was found to be linear in PS/SBR blend, indicating some degree of compatibility but the drawback of elastic moduli indicate incompatibility of the system blend, while it deviates from linearity in blends of PS/SBR filled with glass fiber and talc but the increase in elastic moduli indicates that there is an increase in degree of compatibility between PS and SBR due to adding of glass fiber or talc. The ultrasonic absorptions for longitudinal wave in the temperature range from 298 to 423 K in the studied system were measured using ultrasonic pulse echo technique. Typical results showing the temperature dependence of the ultrasonic absorption at frequencies of 1, 2, 3 and 5 MHz are illustrated for all samples of the different compositions. The study of compositional and temperature dependence of the ultrasonic absorption in the present studied blends reveals the same behavior of the compatibility degree of the blends. Density data of the blends confirmed the ultrasonic results. Also the correlation between hardness and elastic moduli for the present blend systems has been studied.

Dandy-Walker Syndrome: Incidence in a Defined Population of Tabuk, Saudi Arabia

Dandy-Walker syndrome (DWS) is characterized by cystic dilatation of the 4th ventricle and absence of the cerebellar vermis. There may also be posterior fossa enlargement, hydrocephalus, hypoplastic cerebellar hemispheres and other malformations within and outside the central nervous system (CNS). The condition is uncommon, and the incidence is unknown. We studied the incidence of DWS in a defined Saudi Arabian population of military personnel and their dependants. We identified all patients diagnosed with DWS during an 11-year period (1989-1999) from a cohort of 45,274 live births. The incidence of DWS was 1.0 per 100,000 live births per year. The incidence by sex per 100,000 live births per year was 1.24 for males and 0.78 for females. DWS formed 3.5% of our cases of infantile hydrocephalus.