Effect of Li2O doping on electrical properties of CoFe2O4

The solid–solid interactions between cobalt and ferric oxides to produce CoFe₂O₄ were followed up using XRD investigation. The effect of Li₂O-doping on the ferrite formation was also studied. The electrical and dielectric parameters of pure and doped mixed solids precalcined at 1273 K were measured using d.c and a.c instruments.The dopant concentration was varied between 0.5 and 6 mol% Li₂O. The results obtained revealed that Li₂O doping much enhanced the ferrite formation due to an increase in the mobility of the reacting species.

The addition of the smallest amount of Li₂O (0.5 mol%) resulted in measurable variations in the electrical constants (ρ, E_a, ′, ″ and tan δ). Resistivity increased upon increasing the dopant concentration up to 1.5 mol% exceeding the values measured for the undoped sample. Furthermore, the presence of 6 mol% Li₂O brought about a significant decrease of electrical resistivity. Also, the activation energy decreased with increasing the dopant concentration. The dielectric constant behaves according to ε=const. 1/ρ^1/2.

The Li₂O-doping modified the values of different dielectric constants, the change in these constants was found to be strongly dependent on the amount of Li₂O added.These results have been discussed in terms of the potentiality of Li₂O in increasing the mobility of the reacting species involved in the ferrite formation.     

Neutron activation analysis of cheese, eggs, fish, fowl and meats

The concentrations of Br, Ca, Cl, Cu, I, K, Mg, Na, Rb, S and Ti in 44 samples of cheese, eggs, fish, fowl and meats sold in Canada were determined with absolute instrumental neutron activation analysis. The procedure is fully computerized and incorporates one short irradiation and counting only. When an element was not detected, its detection limit was calculated. The nuclear interferences and blanks were taken into account. The nutritional significance of the results is discussed.     

Mathematical modelling of diffusion and reaction for gas-solid catalytic systems with complex reaction networks. Negative effectiveness factors

The concept of effectiveness factor (η) as a measure of diffusional limitations for gas-solid catalytic reactions has gone a long way since the time of Thiele. Multiple steady states giving rise to multiple values of (η) for the same bulk conditions, and η values greater than unity have been widely reported in the literature in the last three decades. In this paper an interesting phenomenon associated with the effectiveness factors (η) for industrial gas-solid catalytic reactions is reported, that is the possible occurrence of negative values of η for certain intermediate components. This physically means that diffusional resistance can also reverse the direction of the net production or consumption of intermediate components in consecutive and/or reversible reaction networks. It is shown both numerically and analytically that the results represent real physical phenomenon and not artefacts resulting from numerical problems or model simplifications. Two industrially important reactions are considered, namely, the steam reforming of natural gas which is a highly endothermic reaction and the partial oxidation of O-xylene to phthalic anhydride which is a highly exothermic reaction.     

Colorimetric determination of some pharmaceutical primary aromatic amines

A method for determination of amines of pharmaceutical interest is based on diazotization of the amine and coupling of the product with ethyl acetoacetate.     

New algorithm for optimal parameter estimation with linear constraints

This paper presents a new algorithm for optimal parameter estimation problems with linear constraints. The algorithm developed is based on least absolute-value approximations. The problem is solved first using a least-error-square technique, where we add to the cost function the equality constraints via Lagrange multipliers, to obtain a good estimate for the residuals of the measurements, having gained this information, we choose a number of measurements with the smallest residuals. This number equals the number of parameters to be estimated minus the number of constraints. Using these measurements together with the constraints, we obtain a number of observations equal to the number of parameters to be estimated. By using this technique, we show that there is no need to either iterate or use linear programming to obtain the estimation.This work was supported by the Natural Sciences and Engineering Research Council of Canada, Grant A4146.     

Formulation of Risperidone as Self-Nanoemulsifying Drug Delivery System in Form of Effervescent Tablets

Risperidone is an atypical antipsychotic drug used to treat schizophrenia. This study aims to formulate risperidone as effervescent tablets to improve patient compliance. Different nanoemulsion combinations were loaded with risperidone to improve its poor water solubility then adsorbed on Aeroperl. The formula showing highest drug dissolution was formulated as effervescent tablets. Factorial design was applied for different tablet formulation variables and the prepared formulae were tested for different criteria in comparison with their corresponding formulae containing drug without nanoemulsion formulation. Statistical analysis was used to determine the most desirable tablet formula considering its Carr index, effervescence time, and drug release.     

Magnesium lactate mixed with EVA polymer/paraffin as an EPR dosimeter for radiation processing application

The dosimetric characteristics of γ-radiation-induced defects in magnesium lactate (ML) rods (3.5 mm×10 mm) formulated by mixing ML with molten mixtures of paraffin wax and EVA copolymer have been investigated using electron paramagnetic resonance (EPR). The EPR spectrum of irradiated ML rods was characterized by a quartet signal with the spectroscopic splitting g-factor of 2.0048±0.0003 at 0.4 mT. The useful dose range of the rod dosimeter was 100 Gy to 80 kGy. The mass attenuation coefficient, μ/ρ, and the mass energy-absorption coefficient, μ_en/ρ, versus energy in the range of 10 keV to 20 MeV indicate that the prepared ML dosimeter is typically adipose tissue equivalent overall this energy range. The overall combined uncertainties (at 2σ) associated with routine dose monitoring in the dose range of 0.1–10 kGy and 10–80 kGy were found to be 6.14% and 6.36%, respectively.     

Momordica charantia Extract Protects against Diabetes-Related Spermatogenic Dysfunction in Male Rats: Molecular and Biochemical Study

More than 90% of diabetic patients suffer from sexual dysfunction, including diminished sperm count, sperm motility, and sperm viability, and low testosterone levels. The effects of Momordica charantia (MC) were studied by estimating the blood levels of insulin, glucose, glycosylated hemoglobin (HbA1c), testosterone (TST), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) in diabetic rats treated with 250 and 500 mg/kg b.w. of the total extract. Testicular antioxidants, epididymal sperm characteristics, testicular histopathology, and lesion scoring were also investigated. Testicular mRNA expression of apoptosis-related markers such as antiapoptotic B-cell lymphoma-2 (Bcl-2) and proapoptotic Bcl-2-associated X protein (Bax) were evaluated by real-time PCR. Furthermore, caspase-3 protein expression was evaluated by immunohistochemistry. MC administration resulted in a significant reduction in blood glucose and HbA1c and marked elevation of serum levels of insulin, TST, and gonadotropins in diabetic rats. It induced a significant recovery of testicular antioxidant enzymes, improved histopathological changes of the testes, and decreased spermatogenic and Sertoli cell apoptosis. MC effectively inhibited testicular apoptosis, as evidenced by upregulation of Bcl-2 and downregulation of Bax and caspase-3. Moreover, reduction in apoptotic potential in MC-treated groups was confirmed by reduction in the Bax/Bcl-2 mRNA expression ratio.