Preparation and Evaluation of Directly-Compressed Indomethacin, Indomethacin Sodium and Indomethacin Meglumine Tablets

A formula containing Compactrol, Ac-Di-Sol, Aerosil 200 and talc was used to prepare directly-compressed tablets of indomethacin and its sodium and meglumine salts. The prepared tablets were evaluated for uniformity of weight and thickness, hardness, friability and content uniformity. Each batch was then divided into two, one was coated with an opaque non-enteric film coat and evaluated for coat thickness uniformity. The dissolution rates of the uncoated and coated tablets and the effect of shelf-storage, at room temperature for 11 months, on drug contents were also studied. Indomethacin meglumine tablets showed the least relative standard deviation of weight and thickness. They exhibited acceptable uniformity of content and coat thickness, and the highest hardness-friability ratio. Also exhibited, uncoated and coated, the best in-vitro release of its drug contents and the maximal stability.     

Central nervous system structure and function in Sturge-Weber syndrome: evidence of neurologic and radiologic progression

Sturge-Weber syndrome is characterized by the presence of a port-wine nevus, epilepsy, stroke-like episodes, headache, and developmental delay. We studied 20 cases to test the hypothesis that decreased cerebral blood flow alters neurologic function by affecting cellular glucose metabolism. Group A consisted of 10 patients with a mean age of 1.75 years and early seizure onset (6.8 months), whereas group B was composed of older patients (mean age, 15.3 years) with later onset of seizures (3.7 years). Neurologic disease was more severe in group A, but group B had more widespread structural brain defects - shown on computed tomographic scans and magnetic resonance imaging - and metabolic brain defects shown on hexamethylpropyleneamine oxime and [18F] fluorodeoxyglucose single photon emission computed tomographic scans. Six group A cases had hypoperfusion at baseline and five of nine had worsening of perfusion and glucose metabolism 1 year later. A total of 119 stroke-like episodes occurred in six group A cases and eight group B cases; there were 65% fewer strokes in children treated with aspirin. The data suggest that progressive hypoperfusion and glucose hypometabolism are associated with neurologic deterioration in Sturge-Weber syndrome. Longitudinal studies are needed to better define the natural history of disease and to evaluate the safety and efficacy of aspirin therapy.     

Peel mechanics of adhesive joints

A review is given of the mechanics of peeling rupture of an adhesive joint, consisting of a flexible adhering strip peled away from a layer of adhesive. Attention is drawn to a number of anomalous results that cannot be accounted for solely, in terms of the thermodynamic work of formation of two new surfaces. The work of detachment is found to be generally much larger than the theoretically-predicted amount. Moreover, the value obtained is greater for thicker layers of adhesive, and for detachment at a peel angle of 180° rather than at 90°. Also, it is found to increase with increasing thickness of the adhering strip, passing through a maximum value in some cases and then decreasing as the strip thickness is increased still further. All of these effects are attributed to dissipative processes, for example, plastic yielding, in one or both of the adhering layers as they are peeled apart. Some quantitative relationships are given for the additional peel forces arising from plastic yielding of the adherend or the adhesive.     

Differential Scanning Calorimetry of Cephalexin-Dextrose and Cephalexin-Aspartame Mixtures

The possible interaction of cephalexin with anhydrous dextrose and with aspartame, in the solid state, was investigaged by comparing the thermal behavior of physical mixtures of the respective original components in different molar ratios, using differential scanning calorimetry. Both anhydrous dextrose and aspartame were found to form complexes with cephalexin. The stoichiometries of these complexes were found to be 1:1 molar complexes between cephalexin and anhydrous dextrose and 4:1 and 1:1 molar complexes between cephalexin and aspartame. Complexed cephalexin was found to decompose at markedly lower temperatures than uncomplexed cephalexin.     

The coefficient of performance for a solar absorption dual cycle

The traditional definition of the coefficient of performance (COP) can create misleading results because this definition does not define the heat input base to be used for estimating the COP. Furthermore, such one-dimensional definitions do not consider other important factors which may affect the system selection.

A new selection criterion for a solar powered dual absorption system will be presented in this paper. The dual cycle, which has the advantage of not using a cooling tower, has often been ignored because of the misleading definition of the COP.

The present paper also describes a lithium bromide dual absorption cycle.     

Floating switch with large-signal capability

Electronic switches using field-effect devices are widely used, but suffer from a low ratio of signal-waveform amplitude to control-waveform amplitude. A switch configuration is described using two devices and overcoming this disadvantage.     

Effect of pre‐germination time of brown rice on serum cholesterol levels of hypercholesterolaemic rats

BACKGROUND: Brown rice is unpolished rice with immeasurable benefits for human health. Brown rice (BR) and pre‐germinated brown rice (PGBR) are known to contain various functional compounds such as γ‐oryzanol, dietary fibre and γ‐aminobutyric acid (GABA). In the present study, the experimental diets containing BR and PGBR (24, 48 h pre‐germination) were used to investigate the influence of pre‐germination time of brown rice on blood cholesterol in Sprague–Dawley male rats. RESULTS: Hypercholesterolaemia and elevation of LDL‐cholesterol were successfully ameliorated by the experimental diets containing BR and PGBR (24 and 48 h pre‐germination). As compared to the control sample, the pre‐germination time had a significant (P < 0.05) effect on blood cholesterol of Sprague–Dawley male rats. It was also found that the significantly (P < 0.05) better effect on lipid profile of hypercholesterolaemic rats was observed by prolonging the pre‐germination time. As compared to non‐germinated brown rice, the germinated brown rice showed the higher cardio‐protective effect on hypercholesterolaemic Sprague–Dawley male rats. CONCLUSION: The present study suggests that the changes of blood cholesterol can be mainly modulated by using the PGBR rather than BR. The prolonging of pre‐germination time led to an increase in the bioactive components, thereby providing a more efficient functional diet affecting the high blood cholesterol. This study suggests that PGBR can be used instead of BR and polished rice in the human diet. Copyright © 2009 Society of Chemical Industry     

Design of high-speed two-stage cascode-compensated operational amplifiers based on settling time and open-loop parameters

Settling behavior of operational amplifiers is of great importance in many applications. In this paper, an efficient methodology for the design of high-speed two-stage operational amplifiers based on settling time is proposed. Concerning the application of the operational amplifier, it specifies proper open-loop circuit parameters to obtain the desired settling time and closed-loop stability. As the effect of transfer function zeros has been taken into account, the proposed methodology becomes more accurate in achieving the desired specifications. Simulation results are presented to show the effectiveness of the methodology.