One‐Step Catalytic Enantioselective α‐Quaternary 5‐Hydroxyproline Synthesis: An Asymmetric Entry to Highly Functionalized α‐Quaternary Proline Derivatives

The highly enantioselective cascade reaction between N‐protected α‐cyanoglycine esters and α,β‐unsaturated aldehydes is disclosed. The reaction represents a one‐step entry to polysubstituted 5‐hydroxyproline derivatives having a quaternary α‐stereocenter generally in high yields with up to >95:5 dr and 99:1 er. It is also a direct catalytic two‐step entry to functionalized α‐quaternary proline derivatives.     

New Challenges for Integrated Circuit Solutions

Integrated circuit solutions have been one of the enabling technologies, contributing to the success of wireless communications. As the focus of the new generation is moving towards higher bandwidths and new services and applications, challenges for the integrated circuit solutions are ever growing. Development focus has shifted from component design and optimization towards significant system oriented content captured both in the hardware platform and supporting software. This integrated approach challenges existing development models, and affects other disciplines related to wireless system development. This paper explores major challenges for integrated circuit solutions emerging from the system-oriented approach.     

Friable rock embedding in methyl methacrylate for thin-sectioning in geological preparations

In most cases, technical problems prevent the production of good geological thin-slabs from friable rocks such as muds, sands or decomposed granites. Usual impregnation methods using Araldite or epoxies lead to incompletely impregnated blocks. Furthermore the excessive heat occurring during polymerization alters the micromorphology of heat sensitive minerals. Methyl methacrylate (MMA) is a widely used plastic for bone embedding. We have developed a new procedure using vacuum infiltration with MMA in a cold environment. Wafers from friable rocks are easily obtained and can be processed in the same way as those of firm and coherent rocks, without grain loss nor mineral heat alterations.     

Optimization of boiler control to improve the load-following capability of power-plant units

The capability to perform fast load changes has been an important issue in the power market, and will become increasingly more so due to the increasing commercialization of the European power market. An optimizing control system for improving the loadfollowing capability of power-plant units has therefore been developed. The system is implemented as a complement, producing control signals to be added to those of the existing boiler control system, a concept which has various practical advantages in terms of implementation and commissioning. The optimizing control system takes account of the multivariable and load-dependent nonlinear characteristics of the boiler process, as a scheduled LQG controller with feedforward action is utilized. The LQG controller improves the control of critical process variables, making it possible to increase the load-following capability of a specific plant. Field tests on a 265 MW coal-fired power-plant unit reveals that the maximum allowable load gradient that can be imposed on the plant, can be increased from 4 to 8 MW/min.     

High throughput electrophysiology: new perspectives for ion channel drug discovery

Proper function of ion channels is crucial for all living cells. Ion channel dysfunction may lead to a number of diseases, so-called channelopathies, and a number of common diseases, including epilepsy, arrhythmia, and type II diabetes, are primarily treated by drugs that modulate ion channels. A cornerstone in current drug discovery is high throughput screening assays which allow examination of the activity of specific ion channels though only to a limited extent. Conventional patch clamp remains the sole technique with sufficiently high time resolution and sensitivity required for precise and direct characterization of ion channel properties. However, patch clamp is a slow, labor-intensive, and thus expensive, technique. New techniques combining the reliability and high information content of patch clamping with the virtues of high throughput philosophy are emerging and predicted to make a number of ion channel targets accessible for drug screening. Specifically, genuine HTS parallel processing techniques based on arrays of planar silicon chips are being developed, but also lower throughput sequential techniques may be of value in compound screening, lead optimization, and safety screening. The introduction of new powerful HTS electrophysiological techniques is predicted to cause a revolution in ion channel drug discovery.     

Investigation on the effect of oxalic acid,succinic acid and aspartic acid on the gas hydrate formation kinetics

Gas hydrate reserves are potential source of clean energy having low molecular weight hydrocarbons trapped in water cages. In this work, we report how organic compounds of different chain lengths and hydrophilicities when used in small concentration may modify hydrate growth and either act as hydrate inhibitors or promoters. Hydrate promoters foster the hydrate growth kinetics and are used in novel applications such as methane storage as solidified natural gas, desalination of sea water and gas separation. On the other hand, gas hydrate inhibitors are used in oil and gas pipelines to alter the rate at which gas hydrate nucleates and grows. Inhibitors such as methanol and ethanol which form strong hydrogen bond with water have been traditionally used as hydrate inhibitors. However, due to relatively high volatility a significant portion of these inhibitors ends up in gas stream and brings further complexity to the safe transportation of natural gas. In this study, organic additives such as oxalic acid, succinic acid and L-aspartic acid (all three) having—COOH group(s) with aspartic acid having an additional—NH₂ group, are investigated for gas hydrate promotion/inhibition behavior. These compounds are polar in nature and thus have significant solubility in liquid water; the presence of weak acidic and water loving (carboxylic/amine groups) moieties makes these organic acids an excellent candidate for further study. This study would pave ways to identify a novel(read better) promoter/inhibitor for gas hydrate formation. Suitable thermodynamic conditions were generated in a stirred tank reactor coupled with cooling system; comparison of gas hydrate formation kinetics with and without additives were carried out to identify the effect of these acids on the formation and growth of hydrates. The possible mechanisms by which these additives inhibit or promote the hydrate growth are also discussed.     

Inverted emulsion cast electrically conducting polyaniline–polystyrene blends

An inverted emulsion method for the synthesis of electrically conductive polyaniline–polystyrene blends of different compositions (10, 30, 50, 70, and 85%, wt/wt) is described. Polymerization of aniline is carried out in chloroform in the dispersed phase by using benzoyl peroxide as a novel oxidant and sulfosalicylic acid as the dopant. The blends synthesized with benzoyl peroxide as the oxidant are of high purity and the excess benzoyl peroxide is readily removed with acetone, which is used to break the emulsion and precipitate the polymer. The absorption spectra, FTIR, FT Raman, and electron paramagnetic resonance spectroscopy confirm the presence of polyaniline in the salt form and polystyrene in the blend. The thermal stability of polyaniline salt decreases with an increase in polystyrene content in the blend. The SEM studies show that the particles of polyaniline–sulfosalicylic acid are dispersed on the polystyrene surface. The blends of polyaniline–polystyrene prepared by the present method were found to display conductivities as high as 0.5–0.1 S cm^?1. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 1163–1171, 2002     

Diamond/CdTe: a new inverted heterojunction CdTe thin film solar cell

Recently the concept of the inverted photovoltaic cell has become more attainable as a practical cell. This thin film cell consists of a p–n heterojunction in which the window layer is p-type and the absorber layer is n-type. The feasibility of a new inverted p–n heterojunction p-diamond/n-CdTe solar cell has been demonstrated. The non-optimized solar cell structure grown on semi-transparent p-diamond yielded an open circuit voltage of 0.23 V and a short circuit current of 1.54 mA/cm² when illuminated.