Self‐assembly of Renewable Nano‐sized Triterpenoids

Studies on plant metabolites have gained renewed interest in recent years because these can serve as renewable chemicals for the development of a sustainable society. Among various plant secondary metabolites, terpenoids constitute the major component and triterpenoids are the 30C subset of it. In recent years, triterpenoids have drawn the attention of scientific community due to many of its potential and realized applications in medicine, drug delivery, thermochromic materials, pollutant capture, catalysis, liquid crystals, etc. In this personal review, we have discussed our computational results carried out on sixty representative naturally occurring triterpenoids demonstrating that all the triterpenoids are renewable functional nano‐entities. Study of the self‐assembly of several triterpenoids such as betulin, betulinic acid, oleanolic acid, glycyrrhetinic acid and arjunolic acid and their derivatives in different liquids have also been discussed. Moreover, the utilization of the resulting supramolecular architectures such as vesicles, spheres, flowers and fibrillar networks of nano‐ to micrometer dimensions and gels have also been discussed in the perspective of green, renewable and nanos.     

Entropy in good manufacturing system: Tool for quality assurance

It has been customary to implement Good Manufacturing Practices (GMP) in pharmaceutical organizations as a systematic and comprehensive quality approach and sometimes by regulatory enforcement. In this scenario, determination of the obvious entropy/disorder arising during the implementation has not been taken care of yet. Therefore, this paper gives the basis for applying query and visual perception of GMP system driven visualization approach, particularly the Laplace equation, to the determination of disorder and deviation pattern inside the GMP system applied in the organization. In this study, a three-dimensional mesh approached with raw and intermediate input handled under GMP parameter is considered to produce high quality products with minimum entropy (variation distribution) by adding the analogy wise different GMP parameters and process variables with Gauss Seidel iteration and thus producing visual picture of the entire system. The approximation involved in applying the equations to the GMP compliant aseptic region was analyzed. Using numerical technique and computer program, the Gauss Seidel iteration equations have been solved with appropriate GMP parameter and process variable. The result indicates that deviations vary over the GMP compliant system and that the process entropy affects the totality of disorderness. Experiments with model of GMP compliant reproductive medicine laboratory confirm that the new method provides optimal manufacturing maintaining GMP and high product quality through the visual representation of the entire system and activity to bring into notice the deviations.     

Discovery of a fluorene class of compounds as inhibitors of botulinum neurotoxin serotype E by virtual screening

Botulinum neurotoxins are one of the most poisonous biological substances known to humans and present a potential bioterrorism threat. There are no therapeutic interventions developed so far. Here, we report the first small molecule non-peptide inhibitor for botulinum neurotoxin serotype E discovered by structure-based virtual screening and propose a mechanism for its inhibitory activity.     

Electron field emission properties of conducting polymer coated multi walled carbon nanotubes

The present work describes the field emission characteristics of conducting polymer coated multi walled carbon nanotubes (MWNTs) field emitters fabricated over flexible graphitized carbon cloth. Nanocomposites involving the combination of MWNTs and conducting polymers polyaniline (PANI) and polypyrrole (PPy) have been prepared by in-situ polymerization method and have been characterized using scanning electron microscopy and transmission electron microscopy. Using spin coating method, field emitters based on PANI/MWNTs and PPy/MWNTs over flexible graphitized carbon cloth have been prepared. The field emission characteristics have been studied using an indigenously fabricated set up in a vacuum chamber with a base pressure of 2 × 10⁻⁵ Pa and the results are discussed. Our results display that the field emission performance of the emitters depends strongly on the work function of the emitting material. Low turn on emission field of 2.12 V/μm at 10 μA/cm² and high emission current density of 1 mA/cm² at 3.04 V/μm have been observed for PANI/MWNTs field emitter.     

Kinetics of esterification of acetic acid with n-butanol over different homogeneous acid catalysts

The esterification reaction of n-butanol and acetic acid has been performed in batch reactor in the presence of different homogeneous acid catalyst, namely sulfuric acid, nitric acid, and para toluene sulfonic acid (p-TSA). The objective of present research work is to investigate kinetic behavior of esterification reaction over the temperature range of 60°C–80°C. The effect of reaction parameter such as catalyst loading varied from 1% to 5% v/v and acid to alcohol molar ratio of 1:1, 1:3, and 1:5 has been observed. A pseudo homogeneous kinetic model has been applied. Kinetic parameters such as equilibrium constant, reaction rate constant, enthalpy, activation energy, and entropy were calculated by the experimental data for different acid catalyst system. It was observed that sulfuric acid gives higher conversion 73% than p-TSA 68.5% and nitric acid 66.25% at temperature of 80°C, 1:1 molar ratio and 3% catalyst concentration. The activation energy was estimated 36448.49, 23324.31 and 19060.156 J/mol K for three different catalyst sulfuric acid, nitric acid and p-TSA respectively. The enthalpy and entropy of the esterification reaction of acetic acid with n-butanol over three different catalysts has been calculated (Enthalpy: 25.788 KJ/mol, 12.256 KJ/mol, 28.320 KJ/mol, Entropy: 88.1 J/mol K, 45.298 J/mol K, 91.44 J/mol K) and found enthalpy is having positive value that shows reaction is endothermic.     

Virus particles and receptor interaction monitored by fluorescence spectroscopy

Native fluorescence spectroscopy (NFS), primarily from tryptophan (trp), was used for in situ investigation of the virus-receptor attachment process in phi6, a lipid-containing bacteriophage from the Cystoviridae family. NFS allowed us to monitor the viral attachment directly to its receptor, which was isolated from the pseudomonad host. Immediately upon mixing, an increase in tryptophan emission intensity was observed followed by a subsequent decrease in emission intensity. The initial increase in emission intensity reflects changes in trp quantum efficiency as the phi6 surface proteins change their conformation as a result of virus attachment to the pilus. The cystovirus spike protein P3 is responsible for receptor recognition and the fluorescence changes observed are likely to be the consequence of its conformational transition at this initial infection stage, providing a kinetic view of this process. The subsequent decrease in trp emission intensity could be due to changes in viral proteins as a result of disassembly of the pili. The technique may have important applications for the dynamic monitoring of additional stages of the virus replication cycle such as assembly, interaction with nucleic acids and maturation. This work expands on a previous demonstration that fluorescence offered a novel tool to detect virus particle interaction with its host cell.     

Simultaneous Quantification of Three Bioactive Lignans,viz., Phyllanthin,Hypophyllanthin, and Niranthin from Phyllanthus amarus Using High-Performance Thin-Layer Chromatography

JPC – Journal of Planar Chromatography – Modern TLC - Phyllanthus amarus, a well-known drug of the Indian Systems of Medicine, possesses a wide variety of pharmacological activities...     

Chromium(VI) Accumulation and Tolerance by Tradescantia pallida: Biochemical and Antioxidant Study

Tradescantia pallida (Wandering jew)—a succulent perennial herb—was screened to be a potent chromium (Cr) accumulator. Its ability to grow under Cr stress was examined by studying biochemical changes and physiological response of the plant in presence of 5–20 mg L^?1 Cr(VI) concentration in hydroponic environment for up to ca. 90 days. Average Cr(VI) bioaccumulation in plant roots reached about 408 μg g^?1 dry weight (dw) after 30 days and up to 536 μg g^?1dw after 60 days of culture. Biochemical changes in the plant exposed to Cr(VI) indicated a reduction in the total carbohydrate and protein content. Furthermore, lipid peroxidation, catalase, peroxidase and ascorbate peroxidase activity were measured in different parts of the plant exposed to Cr(VI). Increased activities of these enzymes showed their important role in overcoming the Cr-induced oxidative stress on the plant.     

Modeling the role of constant and time varying recycling delay on an ecological food chain

We consider a mathematical model of nutrient-autotroph-herbivore interaction with nutrient recycling from both autotroph and herbivore. Local and global stability criteria of the model are studied in terms of system parameters. Next we incorporate the time required for recycling of nutrient from herbivore as a constant discrete time delay. The resulting DDE model is analyzed regarding stability and bifurcation aspects. Finally, we assume the recycling delay in the oscillatory form to model the daily variation in nutrient recycling and deduce the stability criteria of the variable delay model. A comparison of the variable delay model with the constant delay one is performed to unearth the biological relevance of oscillating delay in some real world ecological situations. Numerical simulations are done in support of analytical results.     

Effects of deposition temperature on the structural and morphological properties of SnO2 films fabricated by pulsed laser deposition

Tin oxide (SnO₂) thin films were grown on Si (1 0 0) substrates using pulsed laser deposition (PLD) in O₂ gas ambient (10 Pa) and at different substrate temperatures (RT, 150, 300 and 400 °C). The influence of the substrate temperature on the structural and morphological properties of the films was investigated using X-ray diffraction (XRD), atomic force microscopy (AFM) and scanning electron microscopy (SEM). XRD measurements showed that the almost amorphous microstructure transformed into a polycrystalline SnO₂ phase. The film deposited at 400 °C has the best crystalline properties, i.e. optimum growth conditions. However, the film grown at 300 °C has minimum average root mean square (RMS) roughness of 3.1 nm with average grain size of 6.958 nm. The thickness of the thin films determined by the ellipsometer data is also presented and discussed.