Effect of iron deficiency on developing rat brain

Iron deficiency evolves, slowly through several stages. Early iron deficiency caused a depletion in iron stores as shown by a reduction in the levels of hepatic non heme iron (44%) in the 7 days old pups born to iron deficient mothers. The hemoglobin levels and PCV (packed cell volume) were significantly reduced only after the age of three weeks. The activities of GABA (γ-amino butyric acid) shunt enzymes viz. GDH, GAD and GABA-T (glutamate dehydrogenase, glutamate decarboxylase and GABA-transaminase, respectively) and GABA content were found to decrease during gestation and/or lactation iron deficiency at 1 week (wk), 2wk, 3wk and 4wk of age in the developing rat brains. However GABA binding showed a significant increase at different age groups. The iron deficiency during lactational exposure showed significant alteration in most of the parameters only at the age of 3 weeks onwards. On rehabilitation with iron supplemented diet for 2 weeks, these altered parameters could not attain corresponding control values. A prolonged iron deficiency causing alterations in GABA may lead to neurological and behavioral alterations.     

Battles for technological dominance: an integrative framework

This paper proposes an integrative framework for understanding the process by which a technology achieves dominance when “battling” against other technological designs. We focus on describing the different stages of a dominance battle and propose five battle milestones that in turn define five key phases in the process. We review the literature from several disciplines to identify the key firm- and environment-level factors that affect the outcome of a technology battle and posit that the relative importance of each factor will vary depending on the phase considered. Our framework complements and extends existing literature and has implications both for theory and for management practice.     

Matrix permanent inequalities for approximating joint assignment matrices in tracking systems

This paper examines some of the combinatorial issues associated with the batch data association problem arising in tracking and correlation applications. A procedure is developed that addresses a large class of data association problems involving the calculation of permanents of submatrices of the original association matrix. This procedure yields what is termed the Joint Assignment Matrix (JAM), which can be used to optimally rank associations for hypothesis selection. Because the computational cost of the permanent scales exponentially with the size of the matrix, improved algorithms are developed both for calculating the exact JAM and for generating approximations to it. Empirical results suggest that at least one of the approximations is suitable for real-time hypothesis generation in large scale tracking and correlation applications. Novel theoretical results include an improved upper bound on the calculation of the JAM and new upper bound inequalities for the permanent of general nonnegative matrices. One of these inequalities is an improvement over the best previously known inequality.     

Medicinal plants for treatment of diabetes mellitus

Many plants have been used for the treatment of diabetes mellitus in Indian system of medicine and in other ancient systems of the world. Out of these only a few have been evaluated as per modern system of medicine. From many such plants only extracts have been prepared and their usefulness evaluated in experimental diabetes in animals. In some plants likeAllium cepa, Allium sativum, Ficus bengalensis, Gymnema sylvestre, Pterocarpus marsupium etc. active hypoglycemic principles have been isolated and their mechanism of action studied. Most of them seem to act directly on pancreas (pancreatic effect) and stimulate insulin level in blood. Some have extra pancreatic effect also by acting directly on tissues like liver, muscle etc. and alter favourably the activities of the regulatory enzymes of glycolysis, gluconeogenesis and other pathways. Since the plant products have less side effects, they have the potential as good hypoglycemic drugs. They may also provide clues for the development of new and better oral drugs for diabetes.     

Seaweed uses: the outlook for mariculture

The decade of the 1970s heralded a major research effort into mariculture of economically important red and brown seaweeds. Limited and declining natural populations, lack of synthetic substitutes for the phycocolloids, and their upwardly spiralling costs have emphasized the need for more research in this area. Algal mariculture is now technically and scientifically feasible, but the economic realities are still undetermined. This article examines what is known about seaweed mariculture and discusses where future research efforts must go.     

Standing waves in thin plates tensioned by in-plane loads subject to high frequency excitation

The problem investigated is that of the response of thin plates subjected to pure tone or wide band frequency excitation. A point load is applied perpendicular to the plates. In the case of isotropic or orthotropic plates excited at high frequencies ring shaped standing wave patterns are observed. No classical explanation exists covering this phenomenon. The present analysis indicates that there are two waves radiating from the excitation point with the same frequency, but at different speeds. One wave, a bending wave, is separated from the other one, a membrane wave.     

Magnetic Field Diffusion Through Infinite Conducting Media

The diffusion of the magnetic field due to a step current in an infinitely long ideal conductor, through infinite media is discussed. An analytical solution of the field diffusion through two concentric cylinders of different conductivity is derived using a generalized Ohm's law which considers both solid and fluid conductors. A rigorous mathematical treatment which can be generalized to any number of conducting cylinders is presented.The limiting case of an external superconducting medium is discussed and it is shown that with all the other parameters fixed it represents a lower limit in diffusion time.     

Minimum mass convective fins with variable heat transfer coefficients

Pontryagin's maximum principles are applied to obtain the solution of minimum mass convective fins with variable heat transfer coefficients. It is shown that the volume and the width of the fin are uniquely related to the specified heat transfer rate and the properties of the material. For a power law spatial variation of the heat transfer coefficient, the results are set forth in a dimensionless form and they are given in tables or graphs, in order to aid design procedures. Several properties relating to the optimum volume, base thickness and the width of the fins with the properties of the material are also discussed. The method can also be used to solve problems of minimum mass fins having restricted width, often encountered in practice.