The automated determination of alkyl aryl sulfonates in spray-dried detergents by ultraviolet absorption

An automated procedure has been developed for the determination of alkyl aryl sulfonates in spray-dried detergents. It is based upon the ultraviolet absorbance of alkyl aryl sulfonates at 224 mμ. A Technicon Solid Preparative Sampler is employed to dissolve the sample, dilute it to a fixed volume and remove and aliquot for analysis. The sample aliquots are continuously fed by a Technicon Proportioning Pump to a flow cell in a recording spectrophotometer. All operations, excluding sample weighing, are automatic and analyses can be carried out continuously at the rate of 10 samples per hour. The method has been found to have a coefficient of variation of 3.5%.     

Shedding new light on the molecular architecture of oocytes using a combination of synchrotron Fourier transform-infrared and Raman spectroscopic mapping

Synchrotron Fourier transform-infrared (FT-IR) and Raman microspectroscopy were applied to investigate changes in the molecular architecture of mouse oocytes and demonstrate the overall morphology of the maturing oocyte. Here we show that differences were identified between immature mouse oocytes at the germinal vesicle (GV) and mature metaphase II (MII) stage when using this technology, without the introduction of any extrinsic markers, labels, or dyes. GV mouse oocytes were found to have a small, centrally located lipid deposit and another larger polar deposit of similar composition. MII oocytes have very large, centrally located lipid deposits. Each lipid deposit for both cell types contains an inner and outer lipid environment that differs in composition. To assess interoocyte variability, line scans were recorded across the diameter of the oocytes and compared from three independent trials (GV, n = 91; MII, n = 172), and the data were analyzed with principal component analysis (PCA). The average spectra and PCA loading plots show distinct and reproducible changes in the CH stretching region that can be used as molecular maturation markers. The method paves the way for developing an independent assay to assess oocyte status during maturation providing new insights into lipid distribution at the single cell level.     

Gallium nitride MEMS resonators: how residual stress impacts design and performances

Microsystem Technologies - Starting from Gallium Nitride epitaxially grown on silicon, pre-stressed micro-resonators with integrated piezoelectric transducers have been designed, fabricated, and...     

Residential Water Demand Under Increasing Block Rate Structure: Conservation Conundrum?

Water Resources Management - Water utility managers must balance conservation and revenue goals. A conservation conundrum occurs if price increases lead customers to reduce consumption so much that...     

Effect of calcium infusions of serum calcium and gastric acid secretion

37 patients were studied with calcium infusions. Of these, 20 had previously undergone truncal vagotomy and pyloroplasty for duodenal ulcer disease, and 17 were unoperated patients with duodenal ulcer disease. Calcium was given intravenously either at a dose of 5 mg/kg/h for 3 h, or 4 mg/kg/h for 4 h. Gastric juice was collected by continuous suction. Results showed the 3-hour infusion raised calcium more than the 4-hour infusion. Top serum calcium achieved, however, did not correlate with calcium-stimulated gastric acid output, either with or without vagotomy. Stimulated gastric acid secretion was markedly less with vagotomy than without. It is suggested that the level of gastric acid stimulated by infusions might discriminate complete, from incomplete, vagotomies better than insulin, and that the 4-hour infusion is safer.