Effect of epinephrine on the oxidative desaturation of fatty acids in the rat adrenal gland

Delta-6 and Δ5 desaturation activity of rat adrenal gland microsomes was studied to determine the effect of microsomal protein and the substrate saturation curves. This tissue has a very active Δ6 desaturase for linoleic and α-linoleic acids and a Δ5 desaturase for eicosa-8,11,14-trienoic acid. The administration of epinephrine (1 mg/kg body weight) 12 hr before killing, produced approximately a 50% decrease in desaturation of [1-¹⁴C]linoleic acid to γ-linolenic acid, [1-¹⁴C]α-linolenic acid to octadeca-6,9,12,15-tetraenoic acid and [1-¹⁴C]eicosa-8,11,14-trienoic acid to arachidonic acid. A 30% decrease in Δ5 desaturation activity was also shown after 7 hr of epinephrine treatment. The changes on the oxidative desaturation of the same fatty acids in liver microsomes were similar. No changes were observed in the total fatty acid composition of adrenal microsomes 12 hr after epinephrine treatment. Mechanisms of action of the hormone on the biosynthesis of polyunsaturated fatty acids in the adrenal gland are discussed.     

Improving the quality of high and low-carbon steel rods employed in wire drawing operations

High and low tensile strength as well as high ductility are required for both, high and low-carbon steel rods which are to be further processed in wire drawing operations. In addition to chemical composition, suitable cooling rates are important for the control of mechanical properties, as far as the Stelmor process is concerned. In this investigation, heat transfer models are coupled with the kinetics of austenite transformation into pearlite and ferrite-pearlite, respectively, in order to understand the link between the Stelmor process parameters and the final quality of low and high-carbon steel rods. In applying these models a considerable difference occurred in the mechanical properties of high-carbon rod samples taken from the loop edge of the Stelmor conveyor and those taken from the loop center. The latter showed higher tensile strengths, furthermore, the difference to the lower-strength samples increased with low conveyor speeds. Most homogeneous mechanical properties were found for a conveyor speed of 0.4 m/s. In the case of low-carbon steels, low nitrogen contents during steelmaking and a slow and controlled cooling in the Stelmor process were found to be the most important factors regarding mechanical properties. The conclusions of this investigations are actually being applied to production so as to obtain a better quality of steel rod semies.     

Characterization and Evaluation of Copper Slag as a Bifunctional Photocatalyst for Alcohols Degradation and Hydrogen Production

Topics in Catalysis - With the goal of providing an economically viable method for reducing water pollution and health impact by the mezcal industry wastes, photocatalytic degradation of toxic...     

Length effect on bending properties and evaluation of shear modulus of parallel bamboo strand lumber

European Journal of Wood and Wood Products - One hundred sixty-two parallel bamboo strand lumber (PBSL) beams were tested for the bending properties under three-point bending with variable span....     

Hydrogeologische Erkundung von Grundwasser in der ariden und vulkanisch aufgebauten Westkordillere Boliviens

Grundwasser - In der ariden Westkordillere von Bolivien wurde ein 2000 km2 großes Gebiet geologisch und hydrogeologisch untersucht mit dem Ziel, Bohransatzpunkte zur Grundwassererkundung...     

Heavy metals in urban soils: a case study from the city of Palermo (Sicily), Italy

Concentrations of V, Mn, Cd, Zn, Ni, Cr, Co, Cu, Pb, Hg and Sb were measured on 70 topsoil samples collected from green areas and parks in the city of Palermo (Sicily) in order to: (1) assess the distribution of these heavy metals in the urban environment; (2) discriminate natural and anthropic contributions; and (3) identify possible sources of pollution. Mineralogy, physico-chemical parameters, and major element contents of the topsoils were determined to highlight the influence of 'natural' features on the heavy metal concentrations and their distribution. Medians of Pb, Zn, Cu and Hg concentrations of the investigated urban soils are 202, 138, 63 and 0.68 mgkg(-1), respectively. These values are higher, in some case by different orders of size, than those of unpolluted soils in Sicily that average 44, 122, 34 and 0.07 mg kg(-1). An ensemble of basic and multivariate statistical analyses (cluster analysis and principal component analysis) was performed to reduce the multidimensional space of variables and samples, thus defining two sets of heavy metals as tracers of natural and anthropic influences. Results demonstrate that Pb, Zn, Cu, Sb and Hg can be inferred to be tracers of anthropic pollution, whereas Mn, Ni, Co, Cr, V and Cd were interpreted to be mainly inherited from parent materials. Maps of pollutant distribution were constructed for the whole urban area pointing to vehicle traffic as the main source of diffuse pollution and also showing the contribution of point sources of pollution to urban topsoils.     

Controlling work in process during semiconductor assembly and test operations

This paper introduces a mid-term planning model for scheduling assembly and test operations aimed at minimising the difference between customer demand and product completions each day. A secondary objective is to maximise daily surplus which is a surrogate for throughput. Typically, semiconductor companies have 1000s of products or devices in their catalogue that can be organised into unique groups of up to a 100 devices each. This simplifies the planning process because it is only necessary to consider the groups as a whole rather than the individual devices when constructing schedules. In all, we developed and tested three related models. Each provides daily production rates at each process step for each device group for up to one month at a time. The models are distinguished by how cycle time is treated. The first takes a steady-state approach and uses Little’s Law to formulate a WIP target constraint based on the average cycle time at each processing step. The second and third include integer and fractional cycle times in the variable definitions. To find solutions, raw production data are analysed in a preprocessing step and then converted to input files in a standard format. FlopC++ from the COIN-OR open source software project is used to write and solve the model. Testing was done using three data-sets from the Taiwan AT facility of a global semiconductor firm. By comparing model output with historical data for 6 device groups and 33 process steps, we were able to realise decreases in shortages of up to 40% per month.     

Hydride generation interface for speciation analysis coupling capillary electrophoresis to inductively coupled plasma mass spectrometry

A novel hydride generation (HG) interface for coupling capillary electrophoresis (CE) with inductively coupled plasma mass spectrometry (ICPMS) is presented in this work. The CE-HG-ICPMS interface was applied to the separation and quantitation of common arsenic species. Lack of a commercially available HG interface for CE-ICPMS led to a three concentric tube design allowing alleviation of back pressure commonly observed in CE-HG-ICPMS. Due to the high sensitivity and element-specific detection of ICPMS, quantitative analysis of As(III), As(V), monomethylarsonic acid, and dimethylarsinic acid was achieved. Optimization of CE separation conditions resulted in the use of 20 mmol L(-1) sodium borate with 2% osmotic flow modifier (pH 9.0) and -20 kV applied potential for baseline resolution of each arsenic species in the shortest time. Hydride generation conditions were optimized through multiple electrophoretic separation analyses with 5% HCl and 3% NaBH(4) (in 0.2% NaOH) determined to be the optimum conditions. After completion of system optimization, detection limits obtained for the arsenic species were less than 40 ng L(-1) with electromigration time precision less than 1% within a total analysis time of 9.0 min. Finally, the interface was used for speciation analysis of arsenic in river and tap water samples.