Mukesh Doble

A new series of heteroleptic copper(II) complexes of the type [Cu(L1−3)(diimine)](ClO4) (1–6) have been synthesized using three pyridazine-based ligands (3-chloro-6-(salicylidenehydrazinyl)pyridazine (HL1), 3-chloro-6-(4-diethylaminosalicylidenehydrazinyl)pyridazine (HL2) and 3-chloro-6-(5-bromosalicylidenehydrazinyl)pyridazine (HL3), and diimine (2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen)) as co-ligands. The ligands and their copper(II) complexes have been characterized by elemental analyses and spectroscopic methods. The copper(II) complexes display ligand-field band in the region 641–661 nm suggesting square pyramidal geometry. The optimized structures of the complexes and their molecular orbital calculations obtained by the density functional theory (DFT) also showed five coordinated distorted square pyramidal geometry around the copper(II) ion. The cyclic voltammetric analyses of copper(II) complexes exhibit one-electron irreversible reduction wave (Epc = −0.596 to −0.641 V) in the cathodic potential region. Anti-proliferative activity of the complexes against breast cancer MDA-MB-231 cell line was evaluated by MTT cell proliferation assay, and the clonogenic assay revealed improved cytotoxicity for the complexes with potency higher than the standard drug cisplatin. Since the complexes 3 and 4 with diethylamino substituent displayed higher anti-proliferative activity than the other complexes, these complexes were chosen for apoptosis and cell cycle analysis. The apoptosis induction was analyzed by AO/EB staining, and the flow cytometry showed the inhibition of cell growth at the S-phase of the cell cycle. Additionally, the interaction of copper(II) complexes with FGFR kinase receptor have been studied by in silico molecular docking studies.

We present methodologies to functionalize iron oxide (Fe3O 4) nanoparticles with biosurfactants and biocompatibility results. Positively charged Fe3O4 nanoparticles of average hydrodynamic size ~26 nm is functionalized with four different molecules of interest, viz., surfactin, rhamnolipid, polyethylene glycol (PEG) and dextran. The functionalization results in dramatic alterations in surface potential and hydrodynamic size due to the presence of coated moieties on the nanoparticle interface. The Fourier transform infrared spectroscopy and thermogravimetric analysis confirm the presence of adsorbed moieties on nanoparticles. The phase contrast microscopy studies show the formation of reversible chains of functionalized nanoparticles under an external magnetic field. Cell viability studies using L929 mouse fibroblast cell line show that pure surfactin, rhamnolipid and dextran exhibit cytotoxicity with increase in concentration, whereas, pure PEG exhibit biocompatibility at different concentrations. Accordingly, surfactin and rhamnolipid coated nanoparticles are found to be cytotoxic with increase in concentration and PEG coated nanoparticles are found to be biocompatible. Dextran coated nanoparticles do not exhibit significant increase in biocompatibility. Copyright © 2013 American Scientific Publishers All rights reserved.

Synthesis of low molecular weight poly(dl-lactic-co-glycolic acid), homopolymer poly lactic acid (PLA), and formulation of a hydrophilic blend with polycaprolactam and polyvinyl alcohol is reported. The surface properties and the morphology of the blends were characterized with a goniometer and scanning electron microscopy (SEM). The mechanical property was analyzed with a tensile strength analyzer. The composition of these blends was verified by Fourier transform infrared (FTIR), 1H, and 13C NMR spectroscopy. The biocompatibility and hemocompatibility and the extent of salt encrustation and adhesion of virulent bacterial strains on the blends were also investigated. All the blends were biocompatible and hemocompatible. Adhesion of virulent E. coli was high with blood plasma protein pretreated blends than P. mirabilis. The pattern of encrustation of Ca, Mg, and P was similar on all the blends with calcium being the predominant encrustant. After 3 weeks, 3-10% weight loss was observed with maximum weight loss observed in the poly(lactic-co-glycolic acid) 10:90 based blend. The PLA based blend dominates all the other blends in all the aspects tested. © 2012 American Chemical Society.

Nano-hydroxyapatite (nHA) reinforced magnesium composite (Mg-nHA) was fabricated by friction stir processing (FSP). The effect of smaller grain size and the presence of nHA particles on controlling the degradation of magnesium were investigated. Grain refinement from 1500 μm to 3.5 μm was observed after FSP. In vitro bioactivity studies by immersing the samples in supersaturated simulated body fluid (SBF 5 ×) indicate that the increased hydrophilicity and pronounced biomineralization are due to grain refinement and the presence of nHA in the composite respectively. Electrochemical test to assess the corrosion behavior also clearly showed the improved corrosion resistance due to grain refinement and enhanced biomineralization. Using MTT colorimetric assay, cytotoxicity study of the samples with rat skeletal muscle (L6) cells indicate marginal increase in cell viability of the FSP-Mg-nHA sample. The composite also showed good cell adhesion. © 2014 Elsevier B.V.

Increasing maturity of the crude oil reservoirs across the world have led to the production of waxy crude oil which need economical and efficient methods for enhanced oil recovery (EOR). The studies on the performance of bacteria in the presence of waxy crude oil is rare. In this study, experiments were performed to understand the efficacy of thermophillic microorganism Bacillus subtilis on the biodegradation of waxy crude oil for EOR applications. Bacterial growth, changes in crude oil composition, viscosity reduction, and surface and emulsification activity have been monitored to evaluate the oil degradation capabilities of the bacteria. This study also presents the effect of temperature, salinity, pH, and pressure on the stability of the produced biosurfactant for EOR applications. The biosurfactant produced by bacteria in the presence of crude oil was found to be stable up to 120°C, 10 MPa, 15% salinity, and wide range of pH, and thus favorable for reservoir environment. The crude oil composition before and after degradation at 75°C was determined using gas chromatography-mass spectroscopy and observed to be 60% in one day, while the maximum viscosity reduction was found to be 60% from initial values. Experimental results showed that the bacteria used in this work are capable of surviving at reservoir conditions, and are easy to grow on the waxy crude oil for enhanced oil recovery operations.

The advantages and disadvantages and the and design parameters that need to be considered when selecting microreactors to achieve process intensification (PI) are discussed. Oscillatory flow mixing (OFM) reactor, which includes oscillation of fluids using an external oscillator, is characterized by plug-flow RTD, high heat transfer, and short reaction times. A plate-type reactor combines the high-heat-transfer capabilities of plate heat exchangers with the mixing of microreactors into a single unit, and is designed such that reactants can be injected at different locations along the flow path. The spinning tube-in-a-tube (STT) reactor is capable of creating sub-Kolmogoroff and near-Kolmogoroff eddies, which can reduce reaction time. The spinning disc reactor (SDR) has a very small reactor holdup, such that very hazardous reactions can also be carried out.

Prostaglandins serve as the connecting link between inflammation and cancer. mPGES1, the downstream enzyme in the prostaglandin pathway is considered a better target than COX-2 against the progression of cancer due to the cardiovascular and other complications associated with the inhibition of the latter. Despite the discovery of several compounds that inhibit mPGES1 none could enter the market as drugs because of the problems concerning specificity and unacceptable pharmacokinetic properties. Expression of mPGES1 is inducible in conditions of inflammation and hypoxia and its expression is regulated by a number of transcriptional factors. Targeting these transcription factors could be an alternative approach in the drug discovery process. In this review, the characteristics of the transcription factors, their ability to bind to the promoter of mPGES1 gene and the inhibitors against them have been discussed. The Structure Activity Relationship of the reported inhibitors is highlighted. Finally, practical challenges to further the drug development and future research directions are discussed. These novel compounds that are inhibitors of the major transcription factors are promising candidates for further development as inhibitors of mPGES1.

Conventional oil reserves are under production past several years, leaving the higher end hydrocarbons (paraffins/waxes) in the reservoir. The separation and deposition of these waxy components in the production and surface facilities are predominant when the system temperature reduces below the wax appearance temperature (WAT) during the flow of crude oil from a reservoir to the surface. It is, therefore, necessary to address various challenges posed by long chain paraffins using an economical, versatile, and eco-friendly technique. In the current scenario, microbial degradation of paraffins has gained considerable attention because of its environmentally friendly and operationally safer nature than other methods for sustainable development. In this study, the bio-surfactant producing microorganism Pseudomonas fluorescens, isolated from the marine port in Chennai, India, is used to degrade a wax sample, namely eicosane. The viscosity reduction and the delay in wax appearance temperature has been noticed. This study also analyzes the physico-chemical characteristics of the bio-surfactant produced by the microbe. The degradation of long chain paraffin to short chain molecule is confirmed by the gas chromatography-mass spectrometry (GCMS) result. From the GCMS results, it has been observed that 93% of the wax degraded in 10 days. The amount of bio-surfactant produced by the microbe is found to be as high as 9.5 g/L. The high surface tension reduction, production of higher amount of bio-surfactant, viscosity reduction and high rate of degradation indicates the potential of the microbe in flow assurance, oil-spill, enhanced oil recovery, etc.

Design of compounds having good anti-tubercular activity is gaining much importance in the field of tuberculosis research due to reemergence of antibiotic resistance strains. In this paper quantitative structure activity relationships (QSAR) were developed on chalcones, chalcone-like compounds, flavones and flavanones to understand the relationship between biological activity and structural features. Genetic function approximation (GFA) method was used to identify the descriptors that would lead to good regression equations. The best molecular descriptors identified were Jurs descriptors (Jurs charged partial surface area), hydrogen bond donor, principal moment of inertia, molecular energy, dipole magnetic, molecular area, absorption, distribution, metabolism and excretion (ADME) properties and Chi indices (Kier & Hall chi connectivity indices). Excellent statistically significant models were developed by this approach (r2 = 0.8-0.97) for the four groups of compounds. The cross validated r2 (XV r2) which is an indication of the predictive capability of the model for all the cases was also very good (=0.79-0.94). © 2007 Pharmaceutical Society of Japan.

Exhaustive studies on the degradation of plastics have been carried out in order to overcome the environmental problems associated with synthetic plastic waste. Recent work has included studies of the distribution of synthetic polymer-degrading microorganisms in the environment, the isolation of new microorganisms for biodegradation, the discovery of new degradation enzymes, and the cloning of genes for synthetic polymer-degrading enzymes. Under ambient conditions, polymers are known to undergo degradation, which results in the deterioration of polymer properties, characterized by change in its molecular weight and other physical properties. In this paper mainly the biodegradation of synthetic polymers such as polyethers, polyesters, polycaprolactones, polylactides, polylactic acid, polyurethane, PVA, nylon, polycarbonate, polyimide, polyacrylamide, polyamide, PTFE and ABS have been reviewed. Pseudomonas species degrade polyethers, polyesters, PVA, polyimides and PUR effectively. No microorganism has been found to degrade polyethylene without additives such as starch. None of the biodegradable techniques has become mature enough to become a technology yet.