Oscillating states of driven Langevin systems under large viscous drives.

We provide a perturbative scheme that is suitable to study oscillating states in driven Langevin systems in the large viscous regime. We explicitly determine the oscillating state distribution of an underdamped Brownian particle driven by a time-dependent periodic potential. Apart from the harmonic and anharmonic parameters of the potential, the noise strength and the viscous parameter (or equivalently their ratio referred to as the thermal parameter), which appear in the dynamics of the Brownian particle, are also driven periodically. We specify various nonequilibrium observables, relevant to characterize the oscillating states, and evaluate them to linear order in anharmonic perturbation. We find that the effect of viscous drives on oscillating states is measurable even at leading order and show that the thermodynamic properties of the system in these states are significantly distinct from those in equilibrium or even from those exhibited by oscillating states of overdamped driven systems.

Oscillating states of periodically driven anharmonic Langevin systems.

We investigate the asymptotic distributions of periodically driven anharmonic Langevin systems. Utilizing the underlying SL_{2} symmetry of the Langevin dynamics, we develop a perturbative scheme in which the effect of periodic driving can be treated nonperturbatively to any order of perturbation in anharmonicity. We spell out the conditions under which the asymptotic distributions exist and are periodic and show that the distributions can be determined exactly in terms of the solutions of the associated Hill equations. We further find that the oscillating states of these driven systems are stable against anharmonic perturbations.

Periodically driven harmonic Langevin systems.

Motivated to understand the asymptotic behavior of periodically driven thermodynamic systems, we study the prototypical example of Brownian particle, overdamped and underdamped, in harmonic potentials subjected to periodic driving. The harmonic strength and the coefficients of drift and diffusion are all taken to be T-periodic. We obtain the asymptotic distributions almost exactly treating driving nonperturbatively. In the underdamped case, we exploit the underlying SL_{2} symmetry to obtain the asymptotic state, and to study the dynamics and fluctuations of energies and entropy. We further obtain the two-time correlation functions and investigate the responses to drift and diffusion perturbations in the presence of driving.

Chemical characterization of an Ayurvedic herbo-mineral preparation- Mahalaxmivilas Rasa.

BACKGROUND: To protect the massive trust of patient in Ayurveda, a need aroused for the researches to ascertain the quality, safety & efficacy of herbo-mineral preparations on scientific lines. The rasa-aushadhis are having qualities such as instant effectiveness, requirement in very small dosage and ample therapeutic utility. Mahalaxmi Vilas Rasa [AFI, 20:27] has been used for treatment of a variety of ailments since time immemorial. OBJECTIVE: To prepare Mahalaxmi Vilas Rasa as per standard operating procedures (SoPs) mentioned in classical text and to characterize it chemically using modern analytical techniques. MATERIALS AND METHODS: The drug (Mahalaxmi Vilas Rasa) in three batches was prepared in GMP certified pharmacy. Physico-chemical analysis, HPTLC, Assay of elements by AAS & ICP-AES were carried out as per Ayurvedic Pharmacopoeia of India. Powder X-ray diffraction (XRD) was conducted using Rigaku Ultima-IV X-ray diffractometer. RESULTS: The elemental analysis shown the presence of Mercury, Sulphur, Calcium, Copper, Gold, Iron & Tin etc. and HPTLC revealed presence of organic constituents from plant material. The XRD had indicated that prepared drug contained free sulphur, cinnabar (mercury sulphide added as Kajjali), cassiterite (tin oxide, Vanga Bhasma), orpiment (Hartal, arsenic III sulphide) and mica (Leucite/ Zeolite, Abhrak Bhasma). The drug was also tested for residual pesticide and microbiological contamination which were found within permissible limits. CONCLUSION: Classical pharmaceutical procedures of Mahalaxmi Vilas Rasa showed converting the macro elements into therapeutically effective medicines of micro form. Standards laid down in this study certainly utilized as an important tool for standardization and quality assurance of this herbo-mineral formulation.

Chitosan supramolecularly cross linked with trimesic acid - Facile synthesis, characterization and evaluation of adsorption potential for chromium(VI).

A facile synthesis of Chitosan Supramolecularly cross-linked with Trimesic Acid (CTMA) is reported in this work. The adsorption potential of CTMA for removal of hexavalent chromium was evaluated and the influence of pH, temperature, contact time and adsorbent dose on the adsorption process was investigated. The experimental results showed that CTMA could efficiently adsorb Cr6+ and partially reduce it to the less toxic Cr3+ state. The maximum adsorption capacity of CTMA for Cr6+ was found to be 129.53mg/g at pH 2.0. CTMA and chromium loaded CTMA were characterised by FT-IR, Raman, TGA-DSC, SEM-EDX, XRD, ESR and XPS spectroscopic techniques. Chitosan was observed to be cross- linked with TMA via ionic, hydrogen bonding and pi-pi supramolecular interactions while adsorption of chromium onto CTMA was by electrostatic forces and hydrogen bonding. From the observed results it was evident that CTMA was successfully applied for simultaneous removal of chromium, lead and iron from chrome plating effluent.

Green synthesis of silver nanoparticles using Coffea arabica seed extract and its antibacterial activity.

A novel green source was opted to synthesize silver nanoparticles using dried roasted Coffea arabica seed extract. Bio-reduction of silver was complete when the mixture (AgNO3+extract) changed its color from light to dark brown. UV-vis spectroscopy result showed maximum adsorption at 459 nm, which represents the characteristic surface plasmon resonance of nanosilver. X-ray crystal analysis showed that the silver nanoparticles are highly crystalline and exhibit a cubic, face centered lattice with characteristic (111), (200), (220) and (311) orientations. Particles exhibit spherical and ellipsoidal shaped structures as observed from TEM. Composition analysis obtained from SEM-EDXA confirmed the presence of elemental signature of silver. FTIR results recorded a downward shift of absorption bands between 800-1500 cm(-1) indicting the formation of silver nanoparticles. The mean particle size investigated using DLS was found to be in between 20-30 nm respectively. Anti-bacterial activity of silver nanoparticles on E. coli and S. aureus demonstrated diminished bacterial growth with the development of well-defined inhibition zones.

Hydrogen Adsorption in Flame Synthesized and Lithium Intercalated Carbon Nanofibers--A Comparative Study.

Carbon nanofibers (CNF) have been synthesized under partial combustion conditions in a flame reactor using different mixtures of hydrocarbon gases in the presence and absence of precursors. The hydrogen (H2) adsorption studies have been carried out using a high pressure Sievert's apparatus maintained at a constant temperature (24 degrees C). The flame synthesized CNFs showed high degree of H2 adsorption capacities at 100 atm pressure. The highest H2 capacities recorded have been 4.1 wt% [for CNF produced by liquefied petroleum gas (LPG)-Air (E-17)], 3.7 wt% [for nano carbons produced by Methane-Acetylene-Air (EMAC-4)] and 5.04 wt% for [Lithium intercalated sample (Li-EMAC-4)] respectively.

Biogenic Preparation of Gold Nanostructures Reduced from Piper longum Leaf Broth and Their Electrochemical Studies.

Exploitation of green chemical procedures for the synthesis of metal nanoparticles by biological process has received great attention in the field of nanotechnology. To demonstrate a biogenic method that involves the reduction of aqueous gold ions by the extract of Piper longum leaves leading to the formation of different morphological gold nanoparticles (AuNPs). The formation of gold nano-structures has been characterized by UV-Vis absorption spectroscopy. The X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns indicates the AuNPs are highly crystalline nature with the face-centered cubic (111), (200), (220) and (311) facets, respectively. The AuNPs have different sizes and morphologies that are identified by TEM studies. The involvement of water soluble bio-molecules such as carboxylic acids, flavonoids, proteins and terpenoids were identified by Fourier transform infrared (FT-IR) and Raman spectrum. The responsible mechanism of improving acidic nature and the process of encapsulation of gold nanoparticles by Piper longum extract was discussed. Additionally, we have demonstrated the modified carbon paste electrode using gold nanoparticles by means of cyclic voltammetry in a solution of 1 M KCI and 1 mM [Fe(CN)6]3-/4-. The analysis of cyclic voltammetry shows electronic transmission rate between modified Au-CPE and Bare-CPE electrode increased.

Adsorption of chromium from aqueous solutions using crosslinked chitosan-diethylenetriaminepentaacetic acid.

Chitosan (CH) and its derivatives have been the focus of attention for researchers as potential adsorbents for heavy metal removal. The adsorption potential of chitosan cross-linked with diethylenetriaminepentaacetic acid (CD) for Cr6+ was investigated. CD was characterized by FTIR, XRD, TGA, XPS and ESR techniques. Batch experiments were conducted to optimize the parameters affecting the adsorption of chromium. The optimum pH was found to be 3 and the adsorption process was found to be exothermic. Adsorption isotherms were determined and the maximum adsorption capacity of CD for chromium was found to be 192.3 mg/g which was higher than the adsorption capacity of the adsorbents reported in literature. The thermodynamic parameters, such as Gibbs free energy, changes in enthalpy and changes in entropy change were also evaluated. XPS and ESR studies revealed that Cr6+ adsorbed onto CD was reduced to Cr3+. The efficacy of CD for removal of Cr6+ from chrome plating effluent was demonstrated.

Synthesis of carbon dots from kitchen waste: conversion of waste to value added product.

Synthesis of Carbon dots (C-dots) from bio-degradable waste is a much researched subject now-a-days. The demand for green chemistry and cost-effectiveness lead us to synthesize C-dots from kitchen waste. Nanometer sized carbon particles with unique optical properties were observed during the study. A simplistic approach was used for the synthesis which converted the waste materials into value-added products. Several different analyses were carried out on the obtained product which showed pristine results in comparison with the previous results.

Fabrication, characterization and bioevaluation of silibinin loaded chitosan nanoparticles.

Silibinin is reported to possess multiple biological activities. However, its hydrophobic nature limits its bioavailability compromising in vivo biological activities. Nanoparticles-based delivery of such molecules has emerged as new technique to resolve these issues. Bio-degradable, compatible and adhesive nature of chitosan has recently attracted its suitability as a carrier for biologically active molecules. This study presents fabrication and characterization of chitosan-tripolyphosphate based encapsulation of silibinin. Various preparations of silibinin encapsulated chitosan-tripolyphosphate nanoparticles were studied for particle size, morphology, zeta-potential, and encapsulation efficiencies. Preparations were also evaluated for cytotoxic activities in vitro. The optimized silibinin loaded chitosan nanoparticles were of 263.7±4.1nm in particle size with zeta potential 37.4±1.57mV. Nanoparticles showed high silibinin encapsulation efficiencies (82.94±1.82%). No chemical interactions between silibinin and chitosan were observed in FTIR analysis. Powder X-ray diffraction analysis revealed transformed physical state of silibinin after encapsulation. Surface morphology and thermal behaviour were determined using TEM and DSC analysis. Encapsulated silibinin displayed increased dissolution and better cytotoxicity against human prostate cancer cells (DU145) than silibinin alone.

Synthesis of orderly nanoporous aluminophosphate and zirconium phosphate materials and their catalytic applications.

Amorphous alumino phosphate (AP) and zirconium phosphate (ZP) materials possessing an ordered nanoporosity have been successfully synthesized by a hydrothermal method using a P123 block co-polymer as the structure directing agent. The materials exhibited excellent catalytic activity towards selective alkylation of phenol with cyclohexanol, where AP showed as high as 100% selectivity to produce the industrially important O-alkylation product, while the corresponding ZP selectively produced a C-alkylation product (93% selectivity).

Cost-effective and eco-friendly synthesis of novel and stable N-doped ZnO/g-C3N4 core-shell nanoplates with excellent visible-light responsive photocatalysis.

N-doped ZnO/g-C3N4 hybrid core-shell nanoplates have been successfully prepared via a facile, cost-effective and eco-friendly ultrasonic dispersion method for the first time. HRTEM studies confirm the formation of the N-doped ZnO/g-C3N4 hybrid core-shell nanoplates with an average diameter of 50 nm and the g-C3N4 shell thickness can be tuned by varying the content of loaded g-C3N4. The direct contact of the N-doped ZnO surface and g-C3N4 shell without any adhesive interlayer introduced a new carbon energy level in the N-doped ZnO band gap and thereby effectively lowered the band gap energy. Consequently, the as-prepared hybrid core-shell nanoplates showed a greatly enhanced visible-light photocatalysis for the degradation of Rhodamine B compare to that of pure N-doped ZnO surface and g-C3N4. Based on the experimental results, a proposed mechanism for the N-doped ZnO/g-C3N4 photocatalyst was discussed. Interestingly, the hybrid core-shell nanoplates possess high photostability. The improved photocatalytic performance is due to a synergistic effect at the interface of the N-doped ZnO and g-C3N4 including large surface-exposure area, energy band structure and enhanced charge-separation properties. Significantly, the enhanced performance also demonstrates the importance of evaluating new core-shell composite photocatalysts with g-C3N4 as shell material.

Microviscosity-induced conformational transition in ß-lactoglobulin in the presence of an ionic liquid.

This study reports on the helix-beta conformation transition of bovine ß-lactoglobulin (ßLG) prepared at two different pH conditions (pH 4 and 7.5) and in the presence of the ionic liquid 1-ethyl-3-methylimidazolium ethyl sulfate (IL-emes). The investigation was carried out by combining a range of techniques such as circular dichroic (CD) spectroscopy, steady-state fluorescence spectroscopy, isothermal titration calorimetry (ITC), and transmission electron microscopy. The influence of microviscosity induced by IL-emes on the secondary structure of ßLG was studied using a quartz crystal microbalance and correlated with the steady-state fluorescence emission. The effect of heat on the helix-beta transition in ßLG was directly measured by ITC by titrating ßLG with IL-emes. The net effect of heat after subtraction of the heat of dilution was negative in both cases, suggesting that the protein moves to a stable conformation. The changes in the overall aggregated structures were confirmed by transmission electron microscopy, where a shift in the size and morphology of aggregates was found, from large clusters (size of 70 nm) at pH 4 to smaller aggregates (size of 20 nm) at pH 7.5, which reduced to 7 nm in the presence of the IL. The transformation of helical to beta structure at pH 4 show that the folding pathway in the presence of the ionic liquid is hierarchical, whereas at neutral pH, it appeared to be nonhierarchical and the final native structure was acquired by nonlocal interactions through typical forces involved in the stabilization of the tertiary structure.

Design and synthesis of biaryl aryl stilbenes/ethylenes as antimicrotubule agents.

Two new series of compounds E-2,3,4-trimethoxy-6-styrylbiphenyls and 2,3,4-trimethoxy-6-(1-phenylvinyl)biphenyls were designed, synthesized and evaluated for antitubulin activity. A common intermediate 4,5,6-trimethoxybiphenyl-2-carbaldehydes was employed to generate the two scaffolds. Majority of the analogs inhibited cell proliferation and those functionalized with 3,4-(1,3-dioxolane) and 3,4-difluoro groups were identified as effective inhibitors in both the series. Treatments with 19b, 19c, 22b and 22c arrested cells at G2/M phase, disrupted microtubule network, accumulated tubulin in the soluble fraction and manifested an increased expression of the G2/M marker, Cyclin B1. Molecular docking analysis demonstrated the interaction of these compounds at the colchicine binding site of tubulin.

Low-cost adsorbents from bio-waste for the removal of dyes from aqueous solution.

Activated carbons (ACs) were developed from bio-waste materials like rice husk and peanut shell (PS) by various physicochemical activation methods. PS char digested in nitric acid followed by treatment at 673 K resulted in high surface area up to ∼585 m(2)/g. The novelty of the present study is the identification of oxygen functional groups formed on the surface of activated carbons by infrared and X-ray photoelectron spectroscopy and quantification by using temperature programmed decomposition (TPD). Typical TPD data indicated that each activation method may lead to varying amounts of acidic and basic functional groups on the surface of the adsorbent, which may be a crucial factor in determining the adsorption capacity. It was shown that ACs developed during the present study are good adsorbents, especially for the removal of a model textile dye methylene blue (MB) from aqueous solution. As MB is a basic dye, H(2)O(2)-treated rice husk showed the best adsorption capacity, which is in agreement with the acidic groups present on the surface. Removal of the dye followed Langmuir isotherm model, whereas MB adsorption on ACs followed pseudo-second-order kinetics.

XPS, EXAFS, and FTIR as tools to probe the unexpected adsorption-coupled reduction of U(VI) to U(V) and U(IV) on Borassus flabellifer-based adsorbents.

Palm shell-based adsorbents prepared under five different thermochemical conditions and palm shell powder have been shown to be quite effective for removal of uranium from aqueous solutions. X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and Fourier transform infrared spectroscopy (FTIR) have been used to determine information about the speciation and binding of uranium on the adsorbents under study. Studies indicate that the uranium which is present as uranyl ion in aqueous solution is present in mixed valence states (U(IV), U(V), and U(VI)) when it is bound to the adsorbents. The mechanism of adsorption is likely to be adsorption-coupled reduction as well as complexation. Adsorption of uranium, cesium, and iron was found to be quantitative in binary as well as ternary mixtures.

Entropion-ectropion: the influence of axial globe length on lower eyelid malposition.

PURPOSE: To evaluate the effect of axial globe length and other biometry parameters on age-related lower eyelid malposition. METHODS: Consecutive patients with involutional lower eyelid malposition underwent preoperative biometry with Zeiss IOL Master and Hertel's exophthalmometer prior to surgery. Patients with other causes of eyelid malposition and thyroid eye disease were excluded. GraphPad InStat was used for t test and chi-square statistical analysis. RESULTS: Data on 57 eyelids of 52 Caucasian patients were collected. There were 28 ectropions and 29 entropions. The mean axial globe length in the ectropion group (23.5 mm, standard deviation ± 0.9) was significantly longer than in the entropion group (22.7 mm, standard deviation ± 1.03) (p = 0.008). There was significant sex predilection, with entropion more common in women and ectropion more common in men (p = 0.03). The mean axial globe projection in the ectropion group was 16.6 mm (standard deviation ± 2.4) and in the entropion group was 14.6 mm (standard deviation ± 2.7) (p = 0.002). There was no statistical difference in age, keratometry, amount of astigmatism, and cylinder axis. CONCLUSION: Involutional eyelid malposition directly correlates with axial globe length with the ectropion group having lengthier eyes compared with the entropion group. Hence, axial globe length could be an influential factor in the onset of involutional eyelid malposition.

A spectroscopic study for understanding the speciation of Cr on palm shell based adsorbents and their application for the remediation of chrome plating effluents.

Palm shell based adsorbents prepared under five different thermochemical conditions have been shown to be quite effective for removal of chromium (III and VI) from aqueous solutions. X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FT-IR) have been used to determine information about the speciation and binding of chromium on the adsorbents under study. X-ray photoelectron spectroscopy (XPS) studies indicate that oxidation of lignin moieties takes place concurrently to Cr(VI) reduction and leads to the formation of hydroxyl and carboxyl functions. The maximum adsorption capacity for hexavalent chromium was found to be about 313 mg/g in an acidic medium using PAPSP. This is comparable to other natural substrates and ordinary adsorbents. The efficacy of the adsorbents under study to remove chromium from plating waste water has been demonstrated.

Hierarchical assembly of Sm2Co7/Co magnetic nanoparticles into highly stable and uniform nanospheres.

Hierarchical assembly of colloidal Sm2Co7/Co clusters in the form of nanospheres has been processed through a polyol process. The SmCo nanospheres are found to be robust, uniform ( 100 nm) and tend to self-assemble in the form of ordered superstructures. Each nanosphere consists of large number of discrete fine particles ( 6.0 nm), having two-phase structure of both Sm2Co7 and Co-phases. Upon annealing, these phases transform into Sm2Co17 phase with very high magnetization (169 emu/g). A possible mechanism on the formation of nanospheres from the individual Sm2Co2o7 and Co nanoparticles is also discussed.