Primary giant granulomatous basal meningitis: an unusual presentation of tuberculosis

A case of granulomatous tuberculous meningitis in a 3-year-old child without any known primary disease in any other organ is presented. Tuberculous meningitis is an uncommon presentation of tuberculosis and is characterized by diffuse or circumscribed granulomatous involvement of the meninges, particularly at the base of the brain. Early diagnosis and treatment are essential to prevent the worst events it can bring and to improve the chances of survival. Diagnosis remains difficult because of the lack of reliable clinical diagnostic criteria.     

The effects of pH on phosphate removal from wastewater by electrocoagulation with iron plate electrodes

In this study, the effect of pH on phosphate removal from wastewater by electrocoagulation with iron plate electrodes has been investigated. For this aim, experiments have been carried out controlled initial pH values within the range of 3-9. Effects of initial pH have been analyzed on efficiencies of phosphate removal and energy consumptions. From obtained results, it was found that optimal initial pH is 3. Besides, experiments have been carried out controlled system pH. Effects of system variables have been analyzed on constant pH. From obtained results in these experiments, it was found that optimal system pH is 7.     

Scattering from a cylindrical reflector: modified theory of physical optics solution

The problem of scattering from a perfectly conducting cylindrical reflector is examined with the method of the modified theory of physical optics. In this technique the physical optics currents are modified by using a variable unit vector on the scatterer's surface. These current components are obtained for the reflector, which is fed by an offset electric line source. The scattering integral is expressed by using these currents and evaluated asymptotically with the stationary phase method. The results are compared numerically by using physical optics theory, geometrical optics diffraction theory, and the exact solution of the Helmholtz equation. It is found that the modified theory of physical optics scattering field equations agrees with the geometrical optics diffraction theory and the exact solution of the Helmholtz equation.     

The adsorption kinetics of the cationic dye, methylene blue, onto clay

In this study, adsorption kinetics of a cationic dye, methylene blue, onto clay from aqueous solution with respect to the initial dye concentration, temperature, pH, mixing rate and sorbent dosage were investigated. In order to understand the adsorption mechanism in detail, zeta potentials and the conductivities of clay suspensions at various pH (1-11) and cation exchange capacity (CEC) were measured. Porosity and BET surface area of clay studied were determined. The results showed that the adsorption has been reached to equilibrium in 1 h. It was found that the amount adsorbed of methylene blue increases with decreasing temperature and also with increasing both sorbent dosage and increasing initial dye concentration. Adsorption capacity decreases with increasing pH, except for the natural pH (5.6) of clay suspensions. The adsorption kinetics of methylene blue has been studied in terms of pseudo-first-order, pseudo-second-order sorption and intraparticle diffusion processes thus comparing chemical sorption and diffusion sorption processes. It was found that the pseudo-second-order mechanism is predominant and the overall rate of the dye adsorption process appears to be controlled by the more than one-step.     

Corrosion behavior of boro-tempered ductile iron

In this study, the effect of boro-tempering heat treatment on the microstructure and corrosion behavior of unalloyed ductile iron was investigated. The corrosion characteristics of ductile iron have been determined by current-potential curves. To determine the corrosion rates, the anodic and cathodic Tafel regions extrapolating to corrosion potentials were used. The inhibitor efficiency was calculated from i _corr values. Optical microscope and X-ray diffraction (XRD) were used to examine the microstructure of polished and etched specimens. Thicknesses of the boride layers formed on samples were measured by an optical micrometer attached to the optical microscope. Results show that boro-tempering heat treatment can be successfully applied to ductile iron. The corrosion potential has shifted to more positive values in the boronized samples. The boride layer has behaved like an anodic inhibitor. The boronizing time has affected the corrosion rate. The increase in boronizing time has made the coating thicker, which has increased the corrosion resistance of the material. The best inhibition and the lowest corrosion rate have been performed on the sample which was boronized for 5 hours after cooling in furnace. The tempering at higher temperatures leads to an increase in the corrosion resistance of the materials tested here.     

Ring‐opening metathesis polymerization of bicyclo[2.2.1]hepta‐2,5‐diene (norbornadiene) initiated by new ruthenium(II) complex

The polymerization of norbornadiene (NBD) initiated by a novel ruthenium (Ru)(II) complex ( 3 ) containing 1,1′‐pyridine‐2,6‐diylbis[3‐(dimethylamino)prop‐2‐en‐1‐one] ( 1 ) as ligand has been investigated. Ru complexes exhibit more catalytic activity in the ring‐opening metathesis polymerization (ROMP) of NBD when activated with trimethylsilyldiazomethane (TMSD). The influence of the various experimental parameters such as reaction time and temperature, nature of the solvent and catalyst, ratio of the NBD/Ru, and TMSD addition has been investigated. The polymers have been obtained in high yields with a relatively low polydispersity index for ROMP and a high $ \bar M_n $ and $ \bar M_w $ values in a monomodal distribution. Their structures have been determined by means of FTIR and ¹H‐NMR spectroscopy. Thermal properties have been determined via thermogravimetric analysis and DTG methods. The NBD polymerization results that initiated by Ru‐based catalyst coordinated to amine ligand have been compared to initiated by [RuCl₂(p‐cymene)]₂. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Effects of additives on non-isothermal crystallization kinetics and morphology of isotactic polypropylene

In this study, effects of commercial additives such as antioxidant and stabilizer on the non-isothermal crystallization kinetics of isotactic polypropylene without nucleating agents were investigated by differential scanning calorimetry (DSC) method. Kinetic parameters by Osawa, Avrami and Liu-Mo models and apparent activation energy of the crystallization by Kissinger model were calculated. A polarized optical microscope was also used to observe crystalline morphology of the polypropylene samples crystallized at different cooling rates. On the contrary rate inducing effects of the nucleating agents on the crystallization kinetics of the polypropylene, interestingly, it was found that such types of commercial additives reduced the overall crystallization rate of the polypropylene. Based on the crystallization kinetics and morphology of the samples, it was observed that commercial additives inhibit the chain diffusion toward the growing crystal faces thus slow the crystal growth rate. Furthermore, calculated nucleation activity (ϕ) for the additives showed that they do not act as effective nucleating agents. It was found that the crystallization activation energy of additive-free sample was higher than that of the sample which has commercial additives. Activation energies were found to be 233.6 and 276.7 kJ mol⁻¹ for the PP-1 and PP-2, respectively. Kinetic results also show importance of using of nucleating agents to increase the crystallization rate of polypropylene by increasing the nucleation and thus overall crystallization rate during polypropylene processing operations (esp. for a fast processing cycle in injection molding).