Water-soluble complexes from random copolymer and oppositely charged surfactant. 2. Complexes of poly(ethylene glycol)-based cationic random copolymer and bile salts

The complexes formed between the positively charged random copolymers (RCPs) of methoxy-poly(ethylene glycol) monomethacrylate (MePEGMA) and (3-(methacryloylamino)propyl)trimethylammonium chloride (MAPTAC) with oppositely charged biosurfactants (bile salts) were studied using turbidimetric titration, steady-state fluorescence, dynamic light scattering, and electron microscopy. Studies showed that the complexes of the RCPs of MAPTAC and MePEGMA with less than 68 mol % of PEG content precipitate in water, whereas the complexes of the copolymer with 89 and 94 mol % of PEG content do not precipitate in the entire range of composition of the mixture including stoichiometric compositions when the electroneutral complexes are formed. The complexes with true hydrophobic domains, which are a prerequisite characteristic to serve as a carrier, can be obtained at much lower concentration than the critical micelle concentration of the corresponding surfactant. For a particular surfactant, hydrophobic domains are obtained at lower Z-/+ for the random copolymer with lower PEG content. The hydrodynamic radii of these complexes vary over a range of 20-35 nm. Overall results reveal that these complexes are qualitatively similar to the polyion complex micelles or block ionomer complexes obtained from the block copolymers and oppositely charged surfactants. As the surfactants used in this study are biocompatible, we hope that these soluble particles will be promising vectors in the field of drug delivery.     

Contribution of flyash from coal-fired thermal power plants to uranium contamination of ground water

The elemental concentration of uranium in flyash and coal samples has been investigated using EDXRF and WDXRF techniques. To check the contribution of flyash to uranium contamination of ground water in the Malwa region of Punjab, the flyash and coal samples are collected from Guru Nanak Dev Thermal Power Plant (GNDTPP) in the Bathinda district of Punjab state, India. It is found that uranium concentration in the flyash is below the detection limit of the XRF set up, i.e.?~?1 ppm. It is concluded that uranium contamination in the ground water of Malwa region is not due to the Thermal Power Plant.     

An Efficient and Novel Synthesis of Carbamate Esters from the Coupling of Amines, Halides and Carbon Dioxide in the Presence of Basic Resin

Organic carbamates exhibit unique physical, chemical and biological properties, accommodating variety of applications in pharmacology1 (drugs, prodrugs and drug intermediates), agriculture2 (pesticides, insecticides, fungicides, herbicides etc.) and as synthetic intermediates in chemical industry3. Their use as protection of amino groups in peptide synthesis4 and as linkers in combinatorial chemistry5 is also well known. Functionalization of amines as carbamates offers an attractive method for…     

Synthesis of novel 1,3-thiazin-4-ones by acetylene diester cyclization and their anticancer activities

A novel series of 1,3-thiazin-4-one derivatives containing a piperidyl ring (7–16) were designed and synthesized efficiently by thioamide and acetylene diester cyclization reaction via aminolysis of the ester group and the elimination of an alcohol molecule. The structures of all the novel compounds were established by their FTIR, Mass, ¹H NMR, and ¹³C NMR spectral techniques. The newly synthesized compounds (7–16) were studied for their in vitro anticancer activity against human liver cancer cell lines Hep G2 using MTT assay. The IC₅₀ values of the tested compounds were ranging in between 7.48 ± 0.71 and 56.57 ± 1.37 µM. Further, the apoptosis evaluation by the mitochondrial membrane potential using JC-1 dye was carried out and the results are in good agreement with the cytotoxicity studies.     

Barium nitrate catalyzed one pot synthesis of 1,4‐dihydropyridines under solvent free conditions at room temperature

Barium nitrate acts as an efficient catalyst for the three‐component one pot synthesis of 1,4‐dihydropyridines. Barium nitrate is a safe chemical, and reaction without the use of organic solvents makes the process eco‐friendly.     

Design and Synthesis of Non-Covalent Imidazo[1,2-a]quinoxaline-Based Inhibitors of EGFR and Their Anti-Cancer Assessment

A series of 30 non-covalent imidazo[1,2-a]quinoxaline-based inhibitors of epidermal growth factor receptor (EGFR) were designed and synthesized. EGFR inhibitory assessment (against wild type) data of compounds revealed 6b, 7h, 7j, 9a and 9c as potent EGFR^WT inhibitors with IC₅₀ values of 211.22, 222.21, 193.18, 223.32 and 221.53 nM, respectively, which were comparable to erlotinib (221.03 nM), a positive control. Furthermore, compounds exhibited excellent antiproliferative activity when tested against cancer cell lines harboring EGFR^WT; A549, a non-small cell lung cancer (NSCLC), HCT-116 (colon), MDA-MB-231 (breast) and gefitinib-resistant NSCLC cell line H1975 harboring EGFR^L858R/T790M. In particular, compound 6b demonstrated significant inhibitory potential against gefitinib-resistant H1975 cells (IC₅₀ = 3.65 μM) as compared to gefitinib (IC₅₀ > 20 μM). Moreover, molecular docking disclosed the binding mode of the 6b to the domain of EGFR (wild type and mutant type), indicating the basis of inhibition. Furthermore, its effects on redox modulation, mitochondrial membrane potential, cell cycle analysis and cell death mode in A549 lung cancer cells were also reported.     

Characterization of lead(II)chloride single crystals grown in silica gel

Acousto‐optical materials play an important role in acousto‐optic devices as acousto‐optic modulators. Lead(II) chloride is an acousto‐optical material, having high figure of merit approximately ten times greater than that of lead molybdate, which is an efficient acousto‐optical material. It also possesses high birefringence, low attenuation coefficient, wide transparency range and good mechanical properties. This paper discusses in detail, the growth of single crystals of lead(II) chloride in silica gel by the process of diffusion in a highly acidic medium. Needle‐type lead(II) chloride crystals have been obtained. The crystal system is confirmed to be orthorhombic by powder X‐ray diffraction analysis. To study the optical transparency of the grown crystal, the transmission spectrum has been recorded in the range 190 – 1100 nm. Thermal stability of the crystal is also studied. Results are discussed in detail. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Dependence of particle size on the effective thermal diffusivity and conductivity of nanofluids: role of base fluid properties

Effect of nanoparticle size on effective thermal diffusivity and conductivity of polymeric and water based nanofluids are investigated following thermal wave interference technique. Two sets of nanofluids, prepared by dispersing TiO₂ nanoparticles, with average sizes in the range 5–100?nm, in polyvinyl alcohol and water show opposing particle size dependences. Variations are explained invoking effective medium theory, including size of nanoparticles, molecular weight of base fluid and effects associated with it.     

Silver Nanoparticles and Its Mechanistic Insight for Chronic Wound Healing: Review on Recent Progress

Wounds are structural and functional disruptions of skin that occur because of trauma, surgery, acute illness, or chronic disease conditions. Chronic wounds are caused by a breakdown in the finely coordinated cascade of events that occurs during healing. Wound healing is a long process that split into at least three continuous and overlapping processes: an inflammatory response, a proliferative phase, and finally the tissue remodeling. Therefore, these processes are extensively studied to develop novel therapeutics in order to achieve maximum recovery with minimum scarring. Several growth hormones and cytokines secreted at the site of lesions tightly regulates the healing processes. The traditional approach for wound management has been represented by topical treatments. Metal nanoparticles (e.g., silver, gold and zinc) are increasingly being employed in dermatology due to their favorable effects on healing, as well as in treating and preventing secondary bacterial infections. In the current review, a brief introduction on traditional would healing approach is provided, followed by focus on the potential of wound dressing therapeutic techniques functionalized with Ag-NPs.