Dynamics of Diblock Copolymers in Dilute Solutions

We consider the dynamics of freely translating and rotating diblock (A-B), Gaussian copolymers, in dilute solutions. Using the multiple scattering technique, we have computed the diffusion and the friction coefficients D_AB and Zeta_AB, and the change Eta_AB in the viscosity of the solution as functions of x = N_A/N and t = l_B/l_A, where N_A, N are the number of segments of the A block and of the whole copolymer, respectively, and l_A, l_B are the Kuhn lengths of the A and B blocks. Specific regimes that maximize the efficiency of separation of copolymers with distinct "t" values, have been identified.Comment: 20 pages Revtex, 7 eps figures, needs epsf.tex and amssymb.sty, submitted to Macromolecule

Dynamics and fragmentation mechanism of (CH3-C5H4)Pt(CH3)3 on SiO2 Surfaces

The interaction of (CH3-C5H4)Pt(CH3)3 ((methylcyclopentadienyl)trimethylplatinum)) molecules on fully and partially hydroxylated SiO2 surfaces, as well as the dynamics of this interaction were investigated using density functional theory (DFT) and finite temperature DFT-based molecular dynamics simulations. Fully and partially hydroxylated surfaces represent substrates before and after electron beam treatment and this study examines the role of electron beam pretreatment on the substrates in the initial stages of precursor dissociation and formation of Pt deposits. Our simulations show that on fully hydroxylated surfaces or untreated surfaces, the precursor molecules remain inactivated while we observe fragmentation of (CH3-C5H4)Pt(CH3)3 on partially hydroxylated surfaces. The behavior of precursor molecules on the partially hydroxylated surfaces has been found to depend on the initial orientation of the molecule and the distribution of surface active sites. Based on the observations from the simulations and available experiments, we discuss possible dissociation channels of the precursor.Comment: 18 Pages, 5 Figure

Selection of culture medium and conditions for the production of selenium enriched Saccharomyces cerevisiae

Selenium (Se) yeast is a recognized source of organic food-form of Se and it plays a vital role in animal and human nutrition. The organic Se supplementation in the form of yeast has been shown to have beneficial effects on growth, immune status and reproduction in many animal species, thereby improving the productivity and economical benefits in livestock production. Subsequently, strategies to supplement animal feeds with Se yeast have led to the development of industrial production of Se yeast. The aim of the present study was to improve the yeast biomass production measured as dry cell weight (DCW) and Se enrichment of yeast cells through optimization of the culture conditions and culture media. The culture conditions were optimized by the shake flask experiments. Maximum cell density (2.93 g/LDCW) was observed at pH 5 to 5.5, at 30 °C (2.88 g/L DCW). Significantly higher DCW was recorded when glucose was used as the carbon source (3.09 g/L DCW). The media optimization study carried out in fermentors with five different media (defined medium–A, defined medium-B, synthetic medium, rich medium and industrial medium) showed that the synthetic medium yielded maximum yeast biomass (12.8 g/LDCW) followed by rich medium (11.7 g/L DCW) and defined medium B (10.5 g/LDCW). The Se accumulation was also significantly higher in synthetic medium (2718.3 ppm), followed by industrial medium (2457.7 ppm) and defined medium-B (2251.3 ppm). The methylene blue reduction time (MBRT) was very high ( >15 m) in synthetic medium indicating the highest accumulation of organically bound Se, and MBRT was moderate for defined medium-A and industrial medium ( <10 m).Keywords: Saccharomyces cerevisiae, synthetic medium, carbon source, selenium enrichment, methylene blue reduction time (MBRT)African Journal of Biotechnology Vol. 12(20), pp. 2972-297

Efficient Set Sharing Using ZBDDs

Set sharing is an abstract domain in which each concrete object is represented by the set of local variables from which it might be reachable. It is a useful abstraction to detect parallelism opportunities, since it contains definite information about which variables do not share in memory, i.e., about when the memory regions reachable from those variables are disjoint. Set sharing is a more precise alternative to pair sharing, in which each domain element is a set of all pairs of local variables from which a common object may be reachable. However, the exponential complexity of some set sharing operations has limited its wider application. This work introduces an efficient implementation of the set sharing domain using Zero-suppressed Binary Decision Diagrams (ZBDDs). Because ZBDDs were designed to represent sets of combinations (i.e., sets of sets), they naturally represent elements of the set sharing domain. We show how to synthesize the operations needed in the set sharing transfer functions from basic ZBDD operations. For some of the operations, we devise custom ZBDD algorithms that perform better in practice. We also compare our implementation of the abstract domain with an efficient, compact, bit set-based alternative, and show that the ZBDD version scales better in terms of both memory usage and running time

Role of edaphic factors on VAM fungal colonization and Spore populations in certain tropical wild legumes

Four nodulating annual tropical wild legumes, viz., Alysicarpus monilifer, Desmodium triflorum, Indigofera linnaei and Tephrosia purpurea from three different regions in the Western Ghats ecosystem were investigated to assess their mycorrhizal status. The response ofvesicular-arbuscular mycorrhizal (VAM) root colonization and spore number to edaphicfactors such as soil moisture, pH and available Nand P was analysed. Though the spore number varied significantly both within and between sites, a uniformly high degree ofroot colonization was observed for all the plants in the present study. The spore number recorded was high, rangingfrom 15 to 165 spores gl soil. Spores of sixteen VAM fungal species belonging to Acaulospora, Glomus and Scutellospora were isolated from the rhizosphere soils. Soil moisture generally had a positive influence on VAM colonization and sporulation except in I. linnaei. The pH correlated negatively with root infection in I. linnaei and T. purpurea, but had no influence in the other two species. The effect of 2-pH on sporulation varied with host species and sites. No general correlation existed between available soil nutrients, root colonization and spore number but the influence ofNand P was counteractive on VAM infection. The present study indicates that the response of root colonization and spore number to edaphic factors is a localised rather than a generalised phenomenon

Polymers pushing Polymers: Polymer Mixtures in Thermodynamic Equilibrium with a Pore

We investigate polymer partitioning from polymer mixtures into nanometer size cavities by formulating an equation of state for a binary polymer mixture assuming that only one (smaller) of the two polymer components can penetrate the cavity. Deriving the partitioning equilibrium equations and solving them numerically allows us to introduce the concept of "polymers-pushing-polymers" for the action of non-penetrating polymers on the partitioning of the penetrating polymers. Polymer partitioning into a pore even within a very simple model of a binary polymer mixture is shown to depend in a complicated way on the composition of the polymer mixture and/or the pore-penetration penalty. This can lead to enhanced as well as diminished partitioning, due to two separate energy scales that we analyse in detail.Comment: 10 pages, 6 figure

Radiological and Functional Outcome of Retrograde Nailed Humeral Diaphyseal Fracture

INTRODUCTION: Of all fracture of upper limb, the fracture shaft of humerus is relatively common and easiest to treat. Fracture shaft of humerus accounts for 1% of all adult fractures. There is wide array of good options for their treatment and there is controversy over best methods for many situations. Appropriate decision making for non-operative or operative treatment depends on a thorough understanding of regional anatomy, fracture pattern (Personality of fracture), Classification and finally factors unique to patient (Personality of patient). AIM: To study and analyse radiological union, functional outcome and complications of retrograde unreamed intramedullary interlocking nailing for treating acute humeral diaphyseal fractures in adults. MATERIALS AND METHODS: Our prospective study was from April 2004 to Feb 2006. At our institution, we selected 19 cases of diaphyseal fractures of humerus for this prospective study. All fresh fractures of the humeral shaft chosen for operative treatment including isolated fractures and those in polytrauma patients were nailed in retrograde manner. When there were no clear indications for operative treatment patients were asked for informed consent for retrograde nailing. RESULTS: Out of the 19 patients evaluated, The average hospital stay was 19 days and the mean healing time of a all fractures was 13.74 weeks. Patients with isolated lesions were in hospital for a mean of 14 days. At review, shoulder function was excellent in 17 patients, good in one patient, fair in one patient, no one in poor grade. Elbow function was excellent in 14 patients, good in 3 patients, two in fair grade, no one in poor grade. Total functional out come was excellent in 84% patients, good in 7.8% patients, fair in 6.5% patient poor grade in 1.31% patient. CONCLUSION: The concept of biological fixation in terms of unreamed nailing, closed reduction, static locking and fracture site compression promotes early and adequate fracture union. The problem of shoulder impingement and peri-arthritis shoulder, rotator cuff injury in ante grade nailing are completely avoided with good functional outcome. It helps in providing early rehabilitation and lessens the morbidity. Retrograde humeral nailing is better than anterograde nailing and alternative to plate osteosynthesis for patients with indications for the operative treatment of fractures of the humeral shaft. Retrograde nailing is an attractive option in polytrauma, for isolated fractures which would be difficult to treat conservatively and for patients who require a rapid functional recovery

Mycorrhizae in sedges as related to root character and its ecological significance

Twenty four sedges were examined to assess the role of root characters on mycorrhizal status. Vesicular-arbuscular mycorrhizal (VAM) injection was positively related to root thickness and negatively to root hair number and length. Dried mycorrhizal roots of Bulbostylis barbata, Cyperus cyperinus. C. kyllingia and Fimbristylis ovata served as inocula oj VAMJungi in pot culture study indicating that mycorrhizal sedge roots could act as inocula in initiating and reviving mycorrhizae in natural soils

Quasiparticles as composite objects in the RVB superconductor

We study the nature of the superconducting state, the origin of d-wave pairing, and elementary excitations of a resonating valence bond (RVB) superconductor. We show that the phase string formulation of the t-J model leads to confinement of bare spinon and holon excitations in the superconducting state, though the vacuum is described by the RVB state. Nodal quasiparticles are obtained as composite excitations of spinon and holon excitations. The d-wave pairing symmetry is shown to arise from short range antiferromagnetic correlations

ATTAI VIDAL (LEECH THERAPY) IN SIDDHA SYSTEM OF MEDICINE AND THEIR CURRENT CONCEPT IN THERAPEUTIC APPLICATION - A REVIEW

The Siddha system of medicine is an unique traditional system of medicine practiced in Tamil speaking countries particularly India. In Siddha system of medicine the diseases were treated through internal and external medicine. In external medicine, the leech therapy is one which is used to treat various non-surgical and surgical cases. The leeches have been used for therapeutic purposes since their beginning of civilisation. Ancient Indian, Egyptian, Greek and Arab physicians were used the leeches for wide range of diseases such as inflammatory condition, skin diseases, respiratory disorders, eye diseases, cardiac diseases, urinary and reproductive diseases and dental diseases. The leeches are also used as one of the bloodletting methods in Unani, Ayurveda, and Modern science for various clinical conditions. Recently, researches on leech saliva revealed the presence nearly 100 biologically active compounds such as Hirudin, vasodilators, hyaluronidase, anaesthetics, fibrinases, antibacterial, collagenase etc. The above mentioned pharmacological compounds are injected into human body while sucking of the blood and are responsible for the anaesthetic, anti-inflammatory, anticoagulant and analgesic effect of leech application. In current scenario, the leech therapy is used for various diseases including life threatening diseases such as cardiovascular diseases, cancer, etc. in different system of medicine including modern medicine. Leech therapy is used in plastic and microsurgery as a protective tool against vascular congestion in modern medicine. The Scientific studies on leech saliva were proven and support the leech application in Siddha system of medicine