Testing the applicability of artificial intelligence techniques to the subject of erythemal ultraviolet solar radiation part one: the applicability of a fuzzy rule based approach

This work presents the applicability of applying a fuzzy logic approach to the calculation of noontime erythemal UV irradiance for the plain areas of Egypt. When different combinations of data sets were examined from the test performance point of view, it was found that 91% of the whole series was estimated within a deviation of less than +/-10 mW/m(2), and 9% of these deviations lay within the range of +/-15 mW/m(2) to +/-25 mW/m(2).     

Enantioselective determination of modafinil in pharmaceutical formulations by capillary electrophoresis, and computational calculation of their inclusion complexes

A fast capillary electrophoretic method is described for the separation and determination of the enantiomers of the novel wake-promoting agent, modafinil. Several parameters affecting the separation were studied, including the type and concentration of chiral selector, buffer pH, buffer concentration, voltage and temperature. Good chiral separation of the racemic mixture was achieved in less than 5 min with resolution factor Rs?=?2.51, using a bare fused-silica capillary and a background electrolyte (BGE) of 25 mM H₃PO₄?1 M tris solution; pH 8.0; containing 30 mg mL^?1 of sulfated-β-cyclodextrin (S-β-CD). The separation was carried out in normal polarity mode at 25 ^?C, 18 kV and using hydrostatic injection. Acceptable validation criteria for selectivity, linearity, precision, and accuracy were included. The developed method was successfully applied to the assay of enantiomers of modafinil in pharmaceutical formulations. The computational calculations for the enantiomeric inclusion complexes rationalized the reasons for the different migration times between the modafinil enantiomers.     

Some contributions to the microchemical examination of explosives and ammunition

Summary Spot tests for detecting nitrate, ammonium salts, chlorate, aromatic nitro compounds, nitric acid esters, and the combustion products of black gunpowder can be applied for testing gunpowder and explosives and for detecting traces of such substances with good success. The performance of those tests is described.

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Zusammenfassung Zur Untersuchung von Schießpulver und Sprengstoffen sowie zum Nachweis von Spuren dieser Substanzen lassen sich Tüpfelreaktionen erfolgreich verwenden, die zum Nachweis von Nitrat, Ammoniumsalzen, Chlorat, aromatischen Nitroverbindungen, Salpetersäureestern und Verbrennungsprodukten von Schwarzpulver dienen. Die Ausführung dieser Nachweise wird beschrieben.

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Résumé On reçoit de bons résultats, en employant pour analyser de la poudre et des explosifs et pour déceler des traces de ces substances, les réactions de taches, qui servent au décèlement de nitrates, de sels d'ammonium, de chlorates, de combinaisons nitro, d'éther-sels de l'acide azotique et de produits de combustion de poudres noires. L'auteur décrit le mode d'exécution de ces analyses.

     

Diurnal and Eleven- Year Variations of Neutron Component of Cosmic Rays

Cosmic ray ground observations are used together with the method of coupling coefficients to determine, by spectrographic method, the features of the variational primary energy spectrum of diurnal and eleven-year variations of neutron component of cosmic rays. It is found that the variational energy spectrum responsible for both types of variations can be best described by a constant spectrum up to an upper effective rigidity boundary. The upper cut-off effective rigidity boundary for the variational energy spectrum of diurnal variation was found to change from 105 GV at maximum solar activity to 15.85 GV at minimum solar activity. For Eleven-year variation, R_max was found to have a value of about 20 GV which changes slighly with solar activity due to the change of the coupling coefficients with solar activity.     

Hollow fiber liquid-phase microextraction for the determination of trace amounts of rosiglitazone (anti-diabetic drug) in biological fluids using capillary electrophoresis and high performance liquid chromatographic methods

A three-phase hollow fiber liquid-phase microextraction (HF-LPME) coupled either with capillary electrophoresis (CE) or high performance liquid chromatography (HPLC) with UV detection methods was successfully developed for the determination of trace levels of the anti-diabetic drug, rosiglitazone (ROSI) in biological fluids. The analyte was extracted into dihexyl ether that was immobilized in the wall pores of a porous hollow fiber from 10 mL of aqueous sample, pH 9.5 (donor phase), and was back extracted into the acceptor phase that contained 0.1 M HCl located in the lumen of the hollow fiber. Parameters affecting the extraction process such as type of extraction solvent, HCl concentration, donor phase pH, extraction time, stirring speed, and salt addition were studied and optimized. Under the optimized conditions (extraction solvent, dihexyl ether; donor phase pH, 9.5; acceptor phase, 0.1 M HCl; stirring speed, 600 rpm; extraction time, 30 min; without addition of salt), enrichment factor of 280 was obtained. Good linearity and correlation coefficients of the analyte was obtained over the concentration ranges of 1.0–500 and 5.0–500 ng mL⁻¹ for the HPLC (r² = 0.9988) and CE (r² = 0.9967) methods, respectively. The limits of detection (LOD) and limits of quantitation (LOQ) for the HPLC and CE methods were (0.18, 2.83) and (0.56, 5.00) ng mL⁻¹, respectively. The percent relative standard deviation (n = 6) for the extraction and determination of three concentration levels (10, 250, 500 ng mL⁻¹) of ROSI using the HPLC and CE methods were less than 10.9% and 13.2%, respectively. The developed methods are simple, rapid, sensitive and are suitable for the determination of trace amounts of ROSI in biological fluids.     

Simultaneous determination of atenolol and amiloride in pharmaceutical preparations by capillary zone electrophoresis with capacitively coupled contactless conductivity detection

Capillary zone electrophoresis coupled with a capacitively coupled contactless conductivity detector (CE‐C⁴D) has been employed for the determination of atenolol and amiloride in pharmaceutical formulations. Acetic acid (150 mm ) was used as background electrolyte. The influence of several factors (detector excitation voltage and frequency, buffer concentration, applied voltage, capillary temperature and injection time) was studied. Non‐UV‐absorbing L‐valine was used as internal standard; the analytes were all separated in less than 7 min. The separation was carried out in normal polarity mode at 28°C, 25 kV and using hydrodynamic injection (25 s). The separation was effected in an uncoated fused‐silica capillary (75 μm, i.d. × 52 cm). The CE‐C⁴D method was validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. Calibration curves were linear over the range 5–250 μg/mL for the studied analytes. The relative standard deviations of intra‐ and inter‐day migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of atenolol and amiloride in different pharmaceutical tablet formulations. Copyright © 2010 John Wiley & Sons, Ltd.     

Simultaneous determination of atenolol,chlorthalidone and amiloride in pharmaceutical preparations by capillary zone electrophoresis with ultraviolet detection

Capillary zone electrophoresis methods for the simultaneous determination of the β‐blocker drugs, atenolol, chlorthalidone and amiloride, in pharmaceutical formulations have been developed. The influences of several factors (buffer pH, concentration, applied voltage, capillary temperature and injection time) were studied. Using phenobarbital as internal standard, the analytes were all separated in less than 4 min. The separation was carried out in normal polarity mode at 25°C, 25 kV and using hydrodynamic injection (10 s). The separation was effected in an uncoated fused‐silica capillary (75 μm i.d. × 52 cm) and a background electrolyte of 25 mm H₃PO₄ adjusted with 1 m NaOH solution (pH 9.0) and detection at 198 nm. The method was validated with respect to linearity, limit of detection and quantification, accuracy, precision and selectivity. Calibration curves were linear over the range 1–250 μg/mL for atenolol and chlorthalidone and from 2.5–250 μg/mL for amiloride. The relative standard deviations of intra‐ and inter‐day migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of atenolol, chlorthalidone and amiloride in various pharmaceutical tablets formulations. Copyright © 2010 John Wiley & Sons, Ltd.     

Assessment of the integrity of poly(caprolactone)-b-poly(ethylene oxide) micelles under biological conditions: a fluorogenic-based approach

The integrity of block copolymer micelles is important for their effectiveness and successful delivery of the incorporated drugs. Here we evaluate the integrity of poly(caprolactone)-b-poly(ethylene oxide) micelles in media of varying chemical complexity and in cells by using fluorogenic micelles. Fluorogenic dye fluorescein-5-carbonyl azide diacetate was covalently attached to the micelle-core-forming part of the block copolymer, poly(caprolactone). The fluorescence was not detectable unless the poly(caprolactone)21-b-poly(ethylene oxide)45 micelles were destroyed and the fluorogenic dye was activated by deesterification. The fluorescence of the activated dye from destroyed micelles was easily detectable in various media and in cells. Micelles were stable in simple media such as phosphate-buffered saline but disassembled to varying extents with increasing chemical complexity of the media and addition of serum. The integrity of the internalized micelles within the cells showed a time-dependent decrease but remained largely preserved (80%) after 20 h of incubation with cells. A proof of principle was also demonstrated in vivo in mice. The fluorogenic approach to micelle integrity assessment presented herein should lend itself to other block copolymer micelles and assessments of their integrity in complex biological systems in vitro and in vivo.     

Thermotropic mesomorphism of soft materials bearing carboxylate-supported mu4-oxo tetracupric clusters

A new ligand containing long alkyl (octadecyl) chains was used to obtain the mesogenic complex [L2Cu4(mu4-O)(OAc)4].EtOH (1). This complex was thoroughly characterized and had its molecular structure solved by X-ray diffraction (XRD). Mesomorphic properties were demonstrated by means of polarized microscopy, differential scanning calorimetry, and XRD.