Multi-spectroscopic characterization of bovine serum albumin upon interaction with atomoxetine

The quenching interaction of atomoxetine(ATX) with bovine serum albumin(BSA) was studied in vitro under optimal physiological condition(pH=7.4) by multi-spectroscopic techniques. The mechanism of ATX-BSA system was a dynamic quenching process and was confirmed by the fluorescence spectra and lifetime measurements. The number of binding sites, binding constants and other binding characteristics were computed. Thermodynamic parameters ΔH^0 and ΔS^0 indicated that intermolecular hydrophobic forces predominantly stabilized the drug-protein system. The average binding distance between BSA and ATX was studied by F?rsters theory. UV-absorption, Fourier transform infrared spectroscopy(FT-IR), circular dichroism(CD), synchronous spectra and three-dimensional(3D) fluorescence spectral results revealed the changes in micro-environment of secondary structure of protein upon the interaction with ATX. Displacement of site probes and the effects of some common metal ions on the binding of ATX with BSA interaction were also studied.

Adventitious Roots and Secondary Metabolism

Plants are a rich source of valuable secondary metabolites and in the recent years plant cell, tissue and organ cultures have been developed as an important alternative sources for the production of these compounds. Adventitious roots have been successfully induced in many plant species and cultured for the production of high value secondary metabolites of pharmaceutical, nutraceutical and industrial importance. Adoption of elicitation methods have shown improved synthesis of secondary metabolites in adventitious root cultures. Development of large-scale culture methods using bioreactors has opened up feasibilities of production of secondary metabolites at the industrial levels. In the present review we summarize the progress made in recent past in the area of adventitious root cultures for the production of secondary metabolites.

Interaction of repaglinide with bovine serum albumin:Spectroscopic and molecular docking approaches

Repaglinide (RPG) regulates the amount of glucose by stimulating the pancreas to release insulin in the blood. In view of its biological importance, we have examined the interaction between RPG and a model protein, bovine serum albumin (BSA) employing various spectroscopic, electrochemical and molecular docking methods. Fluorescence spectra of BSA were recorded in the presence and absence of RPG in phosphate buffer of pH 7.4. Fluorescence intensity of BSA was decreased upon the addition of increased concentrations of RPG, indicating the interaction between RPG and BSA. Stern-Volmer quenching analysis results revealed that RPG quenched the intensity of BSA through dynamic quenching mechanism. This was further confirmed from the time-resolved fluorescence measurements. The binding constant as calculated from the spectroscopic and voltammetric results was observed to be in the order of 104M-1 at 298 K, suggesting the moderate binding affinity between RPG and BSA. Competitive experimental results revealed that the primary binding site for RPG on BSA was site II. Absorption and circular dichroism studies indicated the changes in the secondary structure of BSA upon its interaction with RPG. Molecular simulation studies pointed out that RPG was bound to BSA in the hydrophobic pocket of site II.

Photon interaction with semiconductor and scintillation detectors

Mass attenuation coefficients,effective atomic numbers,and electron densities for semiconductor and scintillation detectors have been calculated in the photon energy range 1 keV-100 GeV.These interaction parameters have been found to vary with detector composition and the photon energy.The variation in the parameters with energy is shown graphically for all the partial photon interaction processes.The effective atomic numbers of the detector were compared with the ZXCOM program,and the results were found to be comparable.Efficiencies of semiconductor and scintillation detectors are presented in terms of effective atomic numbers.The study should be useful for comparing the detector performance in terms of gamma spectroscopy,radiation sensitivity,radiation measurement,and radiation damage.The results of the present investigation should stimulate research work for gamma spectroscopy and radiation measuring materials.

Entropy generation analysis from the time-dependent quadratic combined convective flow with multiple diffusions and nonlinear thermal radiation

Diffusions of multiple components have numerous applications such as underground water flow, pollutant movement, stratospheric warming, and food processing. Particularly, liquid hydrogen is used in the cooling process of the aeroplane. Further, liquid nitrogen can find applications in cooling equipment or electronic devices, i.e., high temperature superconducting(HTS) cables. So, herein, we have analysed the entropy generation(EG), nonlinear thermal radiation and unsteady(time-dependent) nature of the flow on quadratic combined convective flow over a permeable slender cylinder with diffusions of liquid hydrogen and nitrogen. The governing equations for flow and heat transfer characteristics are expressed in terms of nonlinear coupled partial differential equations. The solutions of these equations are attempted numerically by employing the quasilinearization technique with the implicit finite difference approximation. It is found that EG is minimum for double diffusion(liquid hydrogen and heat diffusion)than triple diffusion(diffusion of liquid hydrogen, nitrogen and heat). The enhancing values of the radiation parameter R_(d) and temperature ratio θ_(w) augment the fluid temperature for steady and unsteady cases as well as the local Nusselt number. Because, the fluid absorbs the heat energy released due to radiation, and in turn releases the heat energy from the cylinder to the surrounding surface.

Micropropagation of yellow mangosteen:a valuable endemic tree of India

We developed a method for in vitro regenera- tion of Garcinia xanthochymus （yellow mangosteen） from matured seed segments. Multiple shoots were induced on woody plant （WP） medium supplemented with cytokinins. An average of 11 shoots per explant were regenerated from mature seed segments on WP medium containing 20 μM 6-benzylaminopurine. Histological analysis revealed that hypodermal cells of seed segments were initially involved in active division, which later developed into meriste- moids, subsequently leading to the formation of shoot buds. Shoot elongation was achieved by repeated subculturing of seed explants in shoot regeneration medium. Rooting of shoots was achieved on WP medium supplemented with indole-3-butyric acid or s-naphthalene acetic acid. Plant- lets were transplanted to pots containing soil： compost （1：1） and survival rate was 90 %.

Factors affecting somatic embryogenesis in conifers

This review seeks to examine the extreme response of isolated somatic plant cells of apical meristematic tissues of mature conifer trees towards specific stress conditions in vitro resulting in somatic embryo- genesis. Signal molecules regulating embryo development have been described in angiosperms, but very little is known about somatic rejuve- nation in conifers. Recent studies on cloning of mature conifers provide new perspectives on signal molecules on cellular dedifferentiation into the embryogenic pathway. Our recent studies show that signal molecules such as butenolide, calcium ions, salicylic acid, antioxidants, amino acids triacontanol and 24-epibrassinolide all play an important role in the con- version of somatic cells into an embryogenic pathway in many recalcitrant pines. This constitutes a major breakthrough in forest biotechnology with many practical applications in clonal forestry.

Investigating the effect of entrance channel mass asymmetry on fusion reactions using the Skyrme energy density formalism

In the present investigations,the fusion crosssections for the formation of 200Pb compound nucleus(CN)using 16O+184 W,30Si+170Er,and 40Ar+160Gd nuclear reactions at energies above the Coulomb barrier were calculated to understand the effect of entrance channel mass asymmetry(α)on the fusion reactions;the Skyrme energy density formalism(SEDF)was used for this calculation.The SEDF uses the Hartree-Fock-Bogolyubov(HFB)computational program with Skyrme forces such as SkM*,SLy4,and SLy5 to obtain the nucleus-nucleus potential parameters for the above reactions.Using the SEDF model with SkM*,SLy4,and SLy5 interaction forces,the theoretical fusion cross-sections were determined above the barrier energy and compared with the available experimental fusion cross-sections.The results show a close agreement between the theoretical and experimental values for all selected systems at energies well above the barrier.However,near the barrier energies,the theoretical values were observed to be higher than the experimental values.

Non-covalent binding analysis of sulfamethoxazole to human serum albumin:Fluorescence spectroscopy,UV-vis,FT-IR,voltammetric and molecular modeling

This study was designed to examine the interaction of sulfamethoxazole （SMZ） with human serum albumin（HSA）. Spectroscopic analysis of the emission quenching at different temperatures revealed that the quenching mechanism of human serum albumin by SMZ was static mechanism. The binding constant values for the SMZ-HSA system were obtained to be 22,500 L/mol at 288 K, 15,600 L/mol at 298 K, and 8500 L/mol at 308 K. The distance r between donor and acceptor was evaluated according to the theory of Foster energy transfer. The results of spectroscopic analysis and molecular modeling techniques showed that the conformation of human serum albumin had been changed in the presence of SMZ. The thermodynamic parameters, namely enthalpy change （ΔH^0） - 36.0 kJ/mol, entropy change （ΔS^0） - 41.3 Jim01 K and free energy change （ΔG^0） - 23.7 kJ/ mol, were calculated by using van＇t Hoff equation. The effect of common ions on the binding of SMZ to HSA was tested.

Jacobian-free Newton-Krylov subspace method with wavelet-based preconditioner for analysis of transient elastohydrodynamic lubrication problems with surface asperities

This paper presents an investigation into the effect of surface asperities on the over-rolling of bearing surfaces in transient elastohydrodynamic lubrication(EHL) line contact. The governing equations are discretized by the finite difference method. The resulting nonlinear system of algebraic equations is solved by the Jacobian-free Newtongeneralized minimal residual(GMRES) from the Krylov subspace method(KSM). The acceleration of the GMRES iteration is accomplished by a wavelet-based preconditioner.The profiles of the lubricant pressure and film thickness are obtained at each time step when the indented surface moves through the contact region. The prediction of pressure as a function of time provides an insight into the understanding of fatigue life of bearings.The analysis confirms the need for the time-dependent approach of EHL problems with surface asperities. This method requires less storage and yields an accurate solution with much coarser grids. It is stable, efficient, allows a larger time step, and covers a wide range of parameters of interest.

Shielding effectiveness of boron-containing ores in Liaoning province of China against gamma rays and thermal neutrons

In this study, the mass attenuation coefficient of boron-containing ores in the Liaoning province of China was calculated using Win XCOM software to investigate the shielding effectiveness of these ores against gamma rays. The mass attenuation coefficients were also calculated using MCNP-4 B code and compared with Win XCOM results; consequently, a good consistency between the results of Win XCOM and MCNP-4 B was observed. Furthermore, the G-P fitting method was used to evaluate the values of exposure buildup factor(EBF) in the energy range of 0.015–15 Me V up to 40 mean free paths. Among the selected ores, boron-bearing iron concentrate ore(M3)was determined to be the best gamma ray shielding ore owing to its higher values of mass attenuation coefficient and equivalent atomic number and lower value of EBF.Moreover, American Evaluated Nuclear Data File(ENDF/B-VII) was used to analyze the shielding effectivenessagainst thermal neutrons. It was determined that Szaibelyite(M2) is the best thermal neutron shielding material.This study would be useful for demonstrating the potential of boron-containing ores for applications in the field of nuclear engineering and technology.

Gamma-ray and neutron shielding efficiency of Pb-free gadolinium-based glasses

The radiation shielding efficiency of material depends upon photon attenuation, exposure buildup factors and neutron removal capacity. A newly developed Pb-free gadolinium-based glasses in compositions(80-x) B_2O_3-10 Si O_2-10 Ca O-x Gd_2O_3(where x = 15, 20, 25, 30 and35 mol%) had completely been investigated for their shielding efficiency with Geant4 simulation for mass attenuation coefficients and neutron total macroscopic cross section and by calculating exposure buildup factors.The exposure buildup factors for photon energy from 0.015 to 15 Me V had been calculated up to 40 mean free paths using five factors geometric progression method. The mass attenuation coefficients of the Pb-free glasses were simulated for energies from 223 to 2614 ke V and compared with the possible available experimental results. The neutron shielding efficiency of these glasses was discussed by calculating neutron total macroscopic cross section for energies from 1 e V to 14.1 Me V. Present investigations are found to be very useful for applications in nuclear engineering.

Investigation of binding behaviour of procainamide hydrochloride with human serum albumin using synchronous,3D fluorescence and circular dichroism

Interaction of procainamide hydrochloride（PAH） with human serum albumin（HSA） is of great significance in understanding the pharmacokinetic and pharmacodynamic mechanisms of the drug. Multi-spectroscopic techniques were used to investigate the binding mode of PAH to HSA and results revealed the presence of static type of quenching mechanism. The number of binding sites, binding constants and thermodynamic parameters were calculated. The results showed a spontaneous binding of PAH to HSA and hydrophobic interactions played a major role. In addition, the distance between PAH and the Trp–214 was estimated employing the F？rster＇s theory. Site marker competitive experiments indicated that the binding of PAH to HSA primarily took place in subdomain IIA（Sudlow＇s site I）. The influence of interference of some common metal ions on the binding of PAH to HSA was studied. Synchronous fluorescence spectra（SFS）, 3D fluorescence spectra and circular dichroism（CD） results indicated the conformational changes in the structure of HSA.

Multi-spectroscopic investigation of the binding interaction of fosfomycin with bovine serum albumin

The interaction between fosfomycin （FOS） and bovine serum albumin （BSA） has been investigated ef- fectively by multi-spectroscopic techniques under physiological pH 7.4. FOS quenched the intrinsic fluorescence of BSA via static quenching. The number of binding sites n and observed binding constant KA were measured by the fluorescence quenching method. The thermodynamic parameters AG0, AH0 and △S0 were calculated at different temperatures according to the van＇t Hoff equation. The site of binding of FOS in the protein was proposed to be Sudlow＇s site I based on displacement experiments using site markers viz. warfarin, ibuprofen and digitoxin. The distance r between the donor （BSA） and acceptor （FOS） molecules was obtained according to the F^rster theory. The effect of FOS on the conformation of BSA was analyzed using synchronous fluorescence spectra （SFS）, circular dichroism （CD） and 3D fluor- escence spectra. A molecular modeling study further confirmed the binding mode obtained by the ex- perimental studies.

FRET from CdSe/ZnS Core-Shell Quantum Dots to Fluorescein 27 Dye

Semiconductor QDs have emerged as a novel class of fluorophore with unique photoluminescence properties, in particular, CdSe/ZnS core-shell QDs have been successfully used as biocompatible fluorescence resonance energy transfer donors. Here we report FRET between CdSe/ZnS core-shell QDs (donor) and organic dye fluorescein 27 (F27) (acceptor). The results demonstrate the occurrence of efficient energy transfer in the system and the FRET efficiency is not only influenced by the spectral overlap between the QD donor emission and acceptor absorption, it might depend on QDs surface effect also. Efforts are made to correlate quantitatively spectral dependence of FRET rate with acceptor absorption spectrum, Forster distance, transfer efficiency (E) obtained employing steady-state & time-resolved technique.

Fabrication of multiwalled carbon nanotube-surfactant modi fi ed sensor for the direct determination of toxic drug 4-aminoantipyrine

A multi-walled carbon nanotube （MWCNT）-cetyltrimethylammonium bromide （CRAB） surfactant com- posite modified glassy carbon electrode （GCE） was developed as a novel system for the determination of 4-aminoantipyrine（AAP）. The oxidation process was irreversible over the pH range studied and exhibited a diffusion controlled behavior. All experimental parameters were optimized. The combination of MWCNT-CRAB endows the biosensor with large surface area, good biological compatibility, electricity and stability, high selectivity and sensitivity. MWCNT-CTAB/GCE electrode gave a linear response for AAP from 5.0 x 10-9 to 4.0 x 10-8 M with a detection limit of 1.63 x 10 lo M. The modified electrode showed good selectivity against interfering species and also exhibited good reproducibility. The present elec- trochemical sensor based on the MWCNT-CFAB/GCE electrode was applied to the determination of AAP in real samples.

A New Approach to Probability Theory with Reference to Statistics and Statistical Physics

A new approach to probability theory is presented with reference to statistics and statistical physics. At the outset, it is recognized that the “average man” of a population and the “average particle” of a gas are only objects of thought, and not real entities which exist in nature. The concept of average (man) is generalized as a new concept of represental (man) whose epistemological status is intermediate between those of the particular (the man) and the universal (a man). This new concept has become necessary as a result of emergence of statistics as a new branch of human knowledge at the beginning of the nineteenth century. Probability is defined with reference to the represental. The concept of probability is the same in probability theory and in physics. But whereas in statistics the probabilities are estimated using random sequences, in statistical physics they are determined either by the laws of physics alone or by making use of the laws of probability also. Thus in physics we deal with probability at a more basic level than in statistics. This approach is free from most of the controversies we face at present in interpreting probability theory and quantum mechanics.

Eco-friendly reduced graphene oxide for the determination of mycophenolate mofetil in pharmaceutical formulations

Graphene oxide(GO) was synthesized and characterized by scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy(EDX), atomic force microscopy(AFM), X-ray diffraction(XRD), Fourier transform-infrared spectroscopy(FT-IR) and thermogravimetric analysis(TGA). GO was then electrochemically reduced and used for electrochemical study of mycophenolate mofetil(MMF). The electrochemically reduced graphene oxide(ERGO) film on glassy carbon electrode(GCE) showed enhanced peak current for electrooxidation of MMF. MMF exhibited two irreversible oxidation peaks at 0.84 V(peak a_1)and 1.1 V(peak a_2). Effects of accumulation time, pH and scan rate were studied and various electrochemical parameters were calculated. A differential pulse voltammetric method was developed for the determination of MMF in bulk samples and pharmaceutical formulations. Linear relationship was observed between the peak current and concentration of MMF in the range of 40 nM–15 μM with a limit of detection of 11.3 nM. The proposed method is simple, sensitive and inexpensive and, hence, could be readily adopted in clinical and quality control laboratories.

Perch Associated Expression of Phenotypic Plasticity in Limb Development and Sprint Speed in Agamid Lizard Calotes versicolor: A Laboratory Study

New born hatchlings of Calotes versicolor were reared in terrarium having narrow or wide perches for a period of 4-month and their snout vent length（SVL）, tail, fore and hindlimb lengths were measured at monthly intervals. Limb postures（closer to the body or spread away from the body） were also recorded. The sprint speed was recorded in two and four-month old lizards on a 1 m long race track providing 45° or 60° slope. In both the groups, SVL and tail lengths were comparable but the limb lengths and their growth rates were significantly greater in lizards of wider perch group. The lizards reared with narrow perches positioned their limbs closer to the body; while those reared on wider perches spread their limbs away from their body. Further, the latter exhibited significantly higher sprint speed regardless of the slope of the race track over those of narrow perch group. Sprint speeds of lizards in both groups were correlated with the limb sizes. The study showed that the lizards reared on narrow or wide perches exhibited divergent adaptive responses（phenotypic plasticity） by developing longer or shorter limbs and corresponding changes in their sprint speeds. These findings support the idea that availability of perch structure during early development evokes adaptive plasticity in the limb development and associated locomotory performance in arboreal lizards like C. versicolor.

Predatory Cues Influence the Behavioral Responses and Metamorphic Traits of Polypedates maculatus(Anura: Rhacophoridae)

Mechanisms of predator detection and the influence of the presence of nonlethal predators on antipredator defense behavior and metamorphic traits were studied in the Indian tree frog, Polypedates maculatus. Exposure of P. maculatus tadpoles to chemical cues of caged predator（crabs, Barytelphusa spp.） fed with either conspecific or heterogeneric tadpoles, or were starved elicited defense behavior（by avoiding predator zone） in them. Such a behavior was not evident when exposed to predators housed in a glass beaker（visual cues）. Both early（Gosner stage 27–28） and later（Gosner stage 35–36） stage tadpoles when exposed to caged predators（fed with conspecific tadpoles）, prey tadpoles spent less time swimming and remained motionless for longer periods. Yet, the time spent by prey in feeding was unaffected. Further, the predator avoidance behavior exhibited by them was of the same intensity regardless of whether the caged predators were fed or starved implying the influence of predator＇s kairomones. Tadpoles reared with caged predator reached the metamorphic climax stage（MC stage; Gosner stage 42） earlier than those reared without a predator. Size at emergence（Gosner stage 46） was comparable in both the groups. The findings suggest that P. maculatus tadpoles assess predation risk chiefly by sensing kairomones of the predator in eliciting antipredator defense behaviors. Accelerated development and early metamorphosis without any compromise of the size at emergence may be due to their unaltered feeding activity.