4,287 research outputs found

    METHOD DEVELOPMENT AND VALIDATION FOR THE SIMULTANEOUS ESTIMATION OF ASCORBIC ACID AND FOLIC ACID VITAMINS BY REVERSE-PHASE HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY METHOD IN CYANOBACTERIAL METABOLITES AND NUTRACEUTICAL FORMULATION

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    Objective: It was aimed to estimate ascorbic acid (ASC) and folic acid (FLC) in cyanobacterial metabolite by the reverse-phase high-performanceliquid chromatography (RP-HPLC) method, and the work was also extended to nutraceutical formulation.Methods: RP-HPLC method were developed for simultaneous estimation of two vitamins ASC and FLC in cyanobacterial metabolite and nutraceuticalusing isosbestic point at wavelength 280 nm. Method was selected after calculating system suitability and validated as per ICH guidelines.Results: The developed analytical method parameters found within limits prescribed by ICH and USP guidelines. The retention time was found to be2.334 and 3.892, respectively, for ASC and FLC. Limit of detection and limit of quantification for ASC and FLC were found to be 0.087 and 0.263 µg/ml,0.052 and 0.159 µg/ml, respectively. Recovery studies show that method is capable of recovering analytes from its formulation. The method is meetingthe criteria for validation as per the guidelines.Conclusion: The method is simple, precise, specific, and accurate. The newly developed method can be used in pharmaceutical industry for routineanalysis of ASC and FLC in tablet dosage form.Keywords: Cyanobacteria, Nutraceutical, Reverse-phase high-performance liquid chromatography, Ascorbic acid, Folic acid, Vitamins, Metabolites

    The Magneto Rotatory Behaviour of some Optically Active Substances in Solution

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    It deals with the Magneto Rotatory Behaviour of some Optically Active Substances in Solution@IAC

    Universal properties of thermal and electrical conductivity of gauge theory plasmas from holography

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    We propose that for conformal field theories admitting gravity duals, the thermal conductivity is fixed by the central charges in a universal manner. Though we do not have a proof as yet, we have checked our proposal against several examples. This proposal, if correct, allows us to express electrical conductivity in terms of thermodynamical quantities even in the presence of chemical potential.Comment: 13 pages, appendix added, close to journal versio

    On The Phase Structure and Thermodynamic Geometry of R-Charged Black Holes

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    We study the phase structure and equilibrium state space geometry of R-charged black holes in D=5D = 5, 4 and 7 and the corresponding rotating D3D3, M2M2 and M5M5 branes. For various charge configurations of the compact black holes in the canonical ensemble we demonstrate new liquid-gas like phase coexistence behaviour culminating in second order critical points. The critical exponents turn out to be the same as that of four dimensional asymptotically AdS black holes in Einstein Maxwell theory. We further establish that the regions of stability for R-charged black holes are, in some cases, more constrained than is currently believed, due to properties of some of the response coefficients. The equilibrium state space scalar curvature is calculated for various charge configurations, both for the case of compact as well as flat horizons and its asymptotic behaviour with temperature is established.Comment: 1 + 33 pages, LaTeX, 25 figures. References adde

    On RAF Sets and Autocatalytic Cycles in Random Reaction Networks

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    The emergence of autocatalytic sets of molecules seems to have played an important role in the origin of life context. Although the possibility to reproduce this emergence in laboratory has received considerable attention, this is still far from being achieved. In order to unravel some key properties enabling the emergence of structures potentially able to sustain their own existence and growth, in this work we investigate the probability to observe them in ensembles of random catalytic reaction networks characterized by different structural properties. From the point of view of network topology, an autocatalytic set have been defined either in term of strongly connected components (SCCs) or as reflexively autocatalytic and food-generated sets (RAFs). We observe that the average level of catalysis differently affects the probability to observe a SCC or a RAF, highlighting the existence of a region where the former can be observed, whereas the latter cannot. This parameter also affects the composition of the RAF, which can be further characterized into linear structures, autocatalysis or SCCs. Interestingly, we show that the different network topology (uniform as opposed to power-law catalysis systems) does not have a significantly divergent impact on SCCs and RAFs appearance, whereas the proportion between cleavages and condensations seems instead to play a role. A major factor that limits the probability of RAF appearance and that may explain some of the difficulties encountered in laboratory seems to be the presence of molecules which can accumulate without being substrate or catalyst of any reaction.Comment: pp 113-12

    Semi-Holographic Fermi Liquids

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    We show that the universal physics of recent holographic non-Fermi liquid models is captured by a semi-holographic description, in which a dynamical boundary field is coupled to a strongly coupled conformal sector having a gravity dual. This allows various generalizations, such as a dynamical exponent and lattice and impurity effects. We examine possible relevant deformations, including multi-trace terms and spin-orbit effects. We discuss the matching onto the UV theory of the earlier work, and an alternate description in which the boundary field is integrated out.Comment: 26 pages, 4 figures; v2: typos corrected and report number adde

    Holographic Fermi and Non-Fermi Liquids with Transitions in Dilaton Gravity

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    We study the two-point function for fermionic operators in a class of strongly coupled systems using the gauge-gravity correspondence. The gravity description includes a gauge field and a dilaton which determines the gauge coupling and the potential energy. Extremal black brane solutions in this system typically have vanishing entropy. By analyzing a charged fermion in these extremal black brane backgrounds we calculate the two-point function of the corresponding boundary fermionic operator. We find that in some region of parameter space it is of Fermi liquid type. Outside this region no well-defined quasi-particles exist, with the excitations acquiring a non-vanishing width at zero frequency. At the transition, the two-point function can exhibit non-Fermi liquid behaviour.Comment: 52 pages, 6 figures. v3: Appendix F added showing numerical interpolation between the near-horizon region and AdS4. Additional minor comments also adde

    Higher-Energy Composite Fermion Levels in the Fractional Quantum Hall Effect

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    Even though composite fermions in the fractional quantum Hall liquid are well established, it is not yet known up to what energies they remain intact. We probe the high-energy spectrum of the 1/3 liquid directly by resonant inelastic light scattering, and report the observation of a large number of new collective modes. Supported by our theoretical calculations, we associate these with transitions across two or more composite fermions levels. The formation of quasiparticle levels up to high energies is direct evidence for the robustness of topological order in the fractional quantum Hall effect

    Exploration of an innovative draw solution for a forward osmosis-membrane distillation desalination process

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    © 2017, Springer-Verlag Berlin Heidelberg. Forward osmosis (FO) has emerged as a viable technology to alleviate the global water crisis. The greatest challenge facing the application of FO technology is the lack of an ideal draw solution with high water flux and low reverse salt flux. Hence, the objective of this study was to enhance FO by lowering reverse salt flux and maintaining high water flux; the method involved adding small concentrations of Al2(SO4)3 to a MgCl2 draw solution. Results showed that 0.5 M MgCl2 mixed with 0.05 M of Al2(SO4)3 at pH 6.5 achieved a lower reverse salt flux (0.53 gMH) than that of pure MgCl2 (1.55 gMH) using an FO cellulose triacetate nonwoven (CTA-NW) membrane. This was due possibly to the flocculation of aluminum hydroxide in the mixed draw solution that constricted membrane pores, resulting in reduced salt diffusion. Moreover, average water fluxes of 4.09 and 1.74 L/m2-h (LMH) were achieved over 180 min, respectively, when brackish water (5 g/L) and sea water (35 g/L) were used as feed solutions. Furthermore, three types of membrane distillation (MD) membranes were selected for draw solution recovery; of these, a polytetrafluoroethylene membrane with a pore size of 0.45 μm proved to be the most effective in achieving a high salt rejection (99.90%) and high water flux (5.41 LMH) in a diluted draw solution

    Near-Infrared Spectroscopy Measured Cerebral Blood Flow from Spontaneous Oxygenation Changes in Neonatal Brain Injury

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    Neonates with hypoxic-ischaemic (HI) brain injury were monitored using a broadband near-infrared spectroscopy (NIRS) system in the neonatal intensive care unit. The aim of this work is to use the NIRS cerebral oxygenation data (HbD = oxygenated-haemoglobin - deoxygenated-haemoglobin) combined with arterial saturation (SaO2) from pulse oximetry to calculate cerebral blood flow (CBF) based on the oxygen swing method, during spontaneous desaturation episodes. The method is based on Fick's principle and uses HbD as a tracer; when a sudden change in SaO2 occurs, the change in HbD represents a change in tracer concentration, and thus it is possible to estimate CBF. CBF was successfully calculated with broadband NIRS in 11 HIE infants (3 with severe injury) for 70 oxygenation events on the day of birth. The average CBF was 18.0 ± 12.7 ml 100 g-1 min-1 with a range of 4 ml 100 g-1 min-1 to 60 ml 100 g-1 min-1. For infants with severe HIE (as determined by magnetic resonance spectroscopy) CBF was significantly lower (p = 0.038, d = 1.35) than those with moderate HIE on the day of birth
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