Urine analysis of platinum species derived from cis-dichlorodiammineplatinum(II) by high-performance liquid chromatography following derivatization with sodium diethyldithiocarbamate.

A clinically useful method is described for the quantitative analysis of platinum species derived from cis-dichlorodiammineplatinum(II) in urine. The drug and its biodegradation products are derivatized directly in urine by reaction with sodium diethyldithiocarbamate (DDTC) to form a common product, a 2:1 DDTC-platinum adduct. This complex is stable and can be quantitatively extracted into 0.1 volumes of chloroform. An aliquot of the chloroform layer is then subjected to high-performance liquid chromatography on a muBondapak CN column and the eluent monitored spectrophotometrically at 254 nm. At this wavelength the DDTC-platinum adduct has a molar absorptivity of 43,000, and platinum levels of 25 ng/ml or urine can be detected with a precision of +/- 2.5% and an accuracy of +/- 4%.     

A multi-objective joint replenishment inventory model of deteriorated items in a fuzzy environment

In this study, a fuzzy multi-objective joint replenishment inventory model of deteriorating items is developed. The model maximizes the profit and return on inventory investment (ROII) under fuzzy demand and shortage cost constraint. We propose a novel inverse weight fuzzy non-linear programming (IWFNLP) to formulate the fuzzy model. A soft computing, differential evolution (DE) with/without migration operation, is proposed to solve the problem. The performances of the proposed fuzzy method and the conventional fuzzy additive goal programming (FAGP) are compared. We show that the solution derived from the IWFNLP method satisfies the decision maker’s desirable achievement level of the profit objective, ROII objective and shortage cost constraint goal under the desirable possible level of fuzzy demand. It is an effective decision tool since it can really reflect the relative importance of each fuzzy component.     

Electronic versus lattice match for metal-semiconductor epitaxial growth: Pb on Ge(111)

Lattice match is important for epitaxial growth. We show that a competing mechanism, electronic match, can dominate at small film thicknesses for metal-semiconductor systems, where quantum confinement and symmetry requirements may favor a different growth pattern. For Pb(111) on Ge(111), an accidental lattice match leads to a √3 × √3 configuration involving a 30° in-plane rotation at large film thicknesses, but it gives way to an incommensurate (1 × 1) configuration at small film thickness. The transformation follows an approximately inverse-film-thickness dependence with superimposed bilayer oscillations.     

Modelling mechanical property recovery of a linepipe steel in annealing process

In this paper a set of mechanism-based unified viscoplastic constitutive equations has been used to model the effect of microstructural evolution on mechanical property recovery in the annealing process of a cold formed linepipe steel. Dislocation density and plasticity-induced damage accumulation during deformation, and recovery and recrystallisation of the deformed material during subsequent annealing have been modelled. The effects of annealing time on microstructural evolution also have been investigated. Tensile tests were performed on the low carbon ferritic linepipe steel before and after annealing at 700 °C with different holding times. The experimental results have been used to characterise the unified constitutive equations, using an Evolutionary Programming (EP)-based optimisation method. Using these equations, the stress–strain relationships for the interrupted constant strain rate tensile tests were predicted and close agreement between the computed and experimental results was obtained, for various annealing times and for the materials with different amounts of pre-deformation.     

Concerning the diastereofacial selectivity of aldol reactions of chiral methyl ketone enolates: Evidence for remote chelation in the bafilomycin aldol reaction

Evidence is presented that the aldol reactions of the lithium enolates of 4 and 7 proceed preferentially by way of chelated transition structure 19.     

Regional concentration and efficiency in Mexican manufacturing

This paper explores the link between industrial location, concentration, and economic efficiency in Mexican manufacturing. Using a linear programming approach, the authors calculate indices of overall, technical, allocative, and scale efficiency for Mexican manufacturing industries by state to test whether, in 1985, those regions with high levels of industrial concentration were suffering from the costs of congestion. The evidence suggests that, at least at the aggregate level, there continued to be a positive relationship between industry concentration and efficiency in production. There is also evidence that overall efficiency was related to scale efficiency, although highly industrialized regions on the production frontier often operated at inefficient scales. In particular, the most concentrated regions (the Federal District, the state of Mexico, Jalisco, and Nuevo León) consistently display decreasing returns to scale, indicating that the process of industrial concentration may be leading to diseconomies of scale. Finally, an econometric analysis suggests that scale, urbanization, and agglomeration economies are positively related to overall and technical efficiency at the regional level, while foreign ownership is negatively related. Agglomeration economies at the industry level were not significant. The paper also makes a methodological contribution. It is the first application of a distance-function production methodology to measuring regional efficiency in a developing country. It demonstrates how to conduct distance-function efficiency analysis using the newly developed GAMS mathematical programming environment. These tools should be of considerable interest to applied microeconomists.     

PHYSICAL AND PHOTOCHEMICAL PROPERTIES OF A FLUORESCENT CHLOROPHYLL COLLOID

Abstract— A fluorescent colloid of chlorophyll a , of which some qualitative properties were noted by Krasnovsky and Brin⁽¹¹⁾, has been quantitatively characterized. The colloid is formed in neutral PO₄ buffer containing 0 1 to 8.0% Tween 20, and is stable in darkness. The extinction coefficient is 7.8 × 10⁴ 1. mole cm^-1 at the red absorption peak (668 mμ), the yield of fluorescence is ˜ 0.25, and the yield of photoautooxidative bleaching is ˜ 2 times 10^-4. The colloid sensitizes the autooxidation of paratoluenediamine with a yield of ˜0.01 to ˜0.3 depending on light intensity and substrate concentration. The yield is independent of detergent and chlorophyll concentrations. In all respects—except the dependence of yield on illumination—the colloid appears to be physically and photochemically equivalent to dissolved chlorophyll, as known in dilute solutions in organic solvents. The light dependence—the yield is inversely proportional to the cube root of absorbed intensity—could be due to a bimolecular back reaction of a chlorophyll or substrate derivative.     

Linear birefringence parameters determination of a multi-order wave plate via phase detection at large oblique incidence angles

In order to characterize the linear birefringence parameters (LBPs) of a multi-order wave plate (MWP) including ordinary refractive index n_o, extraordinary refractive index n_e and the order number precisely, phase retardation measurement by means of large oblique incidence angle on the MWP has been proposed and demonstrated. However, the effects of spatial shifting and multiple reflections by the MWP depress the accuracy of the measurements significantly. Thus, we propose a retro-reflected geometry in a polarized heterodyne interferometer that can determine the LBPs of a MWP precisely. This method is not only able to reduce the spatial shifting effect but also avoids multiple reflections of the emerging beams. Experimentally, the oblique incidence angle in a range from 30° to 44° was scanned and the highest sensitivity ever for measurements of n_o and n_e for an uncoated MWP was obtained. The detection sensitivity for the refractive indices (n_o,n_e, n_o−n_e) of an uncoated MWP can be up to 10⁻⁶.     

One-step fabrication of surface-relief diffusers by stress-induced undulations on elastomer

In this study, we demonstrated that microscale surface undulations induced by acid treatment could serve as the surface relief on diffusers coated with a layer of PDMS polymer. Since the orientation of undulations was found to be always disordered, these undulations would scatter light uniformly. The periodicity of the undulations could be adjusted by the control of duration of the dipping of the elastomer into H₂SO₄/HNO₃ solutions and by the volume ratio of H₂SO₄/HNO₃ the solution, resulting in the modulation of diffusing ability of diffusers. The optical properties, transmittance, and light diffusivity, were characterised. This proposed approach offers potential for mass production of surface-relief diffusers. In addition, the proposed method allows the creation of undulations on arbitrary substrates.