Light microscopy and scanning electron microscopy: Implications for authentication of misidentified herbal drugs

Plant‐based drugs have reached remarkable acceptability as therapeutic remedy for various diseases due to the adverse effects of contemporary medicines. This increasing popularity of herbal drugs leads to a growing herbal market for the development of plant‐based drugs, nutraceuticals, pharmaceuticals and cosmeceuticals. Herbal drug adulteration is a complex problem which currently has undeniable consequences on health and nutrition. Ambiguities in nomenclature, misidentification and resemblance of colour and texture of the crude herbal drugs are the major causes of adulteration. Three different species commercially marketed under the same trade name Halion are Lepidium apetalum, Asparagus officinalis, and Lepidium didymum. The genuine source of Halion is Lepidium apetalum, which is authenticated by using basic and advanced taxonomic techniques. Morphology, anatomy and palynology of the misidentified sources were done using light and scanning electron microscopic techniques for authentication. This study may help to set microscopic techniques as a tool to achieve quality and standardization of the genuine source of the herbal drug. Phytochemical analysis and biological screening is needed for the further establishment of authenticity and quality of herbal drugs.     

Reliability of the thermodynamic data obtained using the Gibbs-Duhem equation for ternary systems

The reliability of the thermodynamic data obtained by the Gibbs-Duhem equation for binary systems is analyzed, and the testing of this reliability is shown to be highly efficient. A similar testing technique is developed for a ternary system, and the application of this technique to a model system supports its validity and efficiency. The use of the developed technique for testing the data for the ternary Cd-Bi-Pb system of metallic melts confirms its validity and efficiency.     

The investigation of groove geometry effect on heat transfer for internally grooved tubes

An experimental study of surface heat transfer and friction characteristics of a fully developed turbulent air flow in different grooved tubes is reported. Tests were performed for Reynolds number range 10,000–38,000 and for different geometric groove shapes (circular, trapezoidal and rectangular). The ratio of tube length-to-diameter is 33. Among the grooved tubes, heat transfer enhancement is obtained up to 63% for circular groove, 58% for trapezoidal groove and 47% for rectangular groove, in comparison with the smooth tube at the highest Reynolds number (Re = 38,000). Correlations of heat transfer and friction coefficient were obtained for different grooved tubes. In evaluation of thermal performance, it is seen that the grooved tubes are thermodynamically advantageous (Ns, a < 1) up to Re = 30,000 for circular and trapezoidal grooves and up to Re = 28,000 for rectangular grooves. It is observed that there is an optimum value of the entropy generation number at about Re = 17,000 for all investigated grooves.     

Influences of sodium borohydride concentration on direct borohydride fuel cell performance

In this work, the effects of sodium borohydride concentration on the performance of direct borohydride fuel cell, which consisted of Pd/C anode, Pt/C cathode and Na⁺ form Nafion^® membrane as the electrolyte, have been investigated in steady state/steady-flow and uniform state/uniform-flow systems. The experimental results have revealed that the power density increased as the sodium borohydride concentration increased in the SSSF system. Peak power densities of 7.1, 10.1 and 11.7 mW cm⁻² have been obtained at 0.5, 1 and 1.5 M, respectively. However, the performance has decreased when the sodium borohydride concentration has been increased, and the fuel utilization ratios of 29.8%, 21.6% and 20.4% have been obtained at 0.5, 1 and 1.5 M, respectively in the USUF system.     

Actors: A unifying model for parallel and distributed computing

Parallel computing and distributed computing have traditionally evolved as two separate research disciplines. Parallel computing has addressed problems of communication-intensive computation on tightly-coupled processors while distributed computing has been concerned with coordination, availability, timeliness, etc., of more loosely coupled computations. Current trends, such as parallel computing on networks of conventional processors and Internet computing, suggest the advantages of unifying these two disciplines. Actors provide a flexible model of computation which supports both parallel and distributed computing. One may evaluate the utility of a programming paradigm in terms of four criteria: expressiveness, portability, efficiency, and performance predictability. We discuss how the Actor model and programming methods based on it support these goals. In particular, we provide an overview of the state of the art in Actor languages and their implementation. Finally, we place this work in the context of recent developments in middleware, the Java language, and agents.     

Scalable concurrent computing

This paper focusses on the challenge of building and programming scalable concurrent computers. The paper describes the inadequacy of current models of computing for programming massively parallel computers and discusses three universal models of concurrent computing — developed respectively by programming, architecture and algorithm perspectives. These models provide a powerful representation for parallel computing and are shown to be quite close. Issues in building systems architectures which efficiently represent and utilize parallel hardware resources are then discussed. Finally, we argue that by using a flexible universal programming model, an environment supporting heterogeneous programming languages can be developed.