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The mce1 operon of Mycobacterium tuberculosis, which codes the Mce1 transporter, facilitates the transport of fatty acids. Fatty acids are one of the major sources for carbon and energy for the pathogen during its intracellular survival and pathogenicity. The mce1 operon is transcriptionally regulated by Mce1R, a VanR-type regulator, which could bind specific ligands and control the expression of the mce1 operon accordingly. This work reports computational identification of Mce1R-specific ligands. Initially by employing cavity similarity search algorithm by the ProBis server, the cavities of the proteins similar to that of Mce1R and the bound ligands were identified from which fatty acids were selected as the potential ligands. From the earlier-generated monomeric structure, the dimeric structure of Mce1R was then modeled by the GalaxyHomomer server and validated computationally to use in molecular docking and molecular dynamics simulation analysis. The fatty acid ligands were found to dock within the cavity of Mce1R and the docked complexes were subjected to molecular dynamics simulation to explore their stabilities and other dynamic properties. The data suggest that Mce1R preferably binds to long-chain fatty acids and undergoes distinct structural changes upon binding.

Background: Dermatoglyphic characteristics for identification of sex play an important role in forensic and medico-legal purposes. Hence, it considered to be the most precise and reliable indicators for personal and gender identification. Such types of information on Bengali speaking Hindu population are very scanty. This was tempted the present authors to assess the sex-wise variation of digital dermatoglyphic traits in a sample from West Bengal, India. Materials and Methods: A total 168 participants were recruited to obtain basic information and fingertip impression of the participants. Impressions were taken by using Ink method (Calcutta Ink) and examined with hand-lens. Results: The mean age for male participants was 31.30 16.13 and for females it was 32.1113.30. The loop pattern is observed more frequent (46.13%) compared to whorl (36.25%), arch (10.89%) and composite (6.72%). Females have a more loop (47.84%) and arch (12.26%) patterns than males (43.48% and 8.79% respectively. The whorl (39.85%) and composite (7.88%) patterns are observed more frequently in males as compared to females (33.92% and 5.98% respectively). Furuhata’s Index is more frequent in males (91.64) than females (70.9) but both the Dankmeijer’s and Poll’s Index are higher in females (36.13 and 25.61 respectively) than males (22.05 and 20.21 respectively). However, in case of Pattern Intensity Index there is slightly a sex difference for males and females (12.32 and 11.57 respectively). Conclusions: It was concluded that differences in the finger print pattern, combinations and indices can be used as an important tool for the determination of sex in medico-legal and forensic purposes. Keywords: Bengali Hindu, Dermatoglyphics, Forensic identification, Sexual Dimorphism

The mce1 operon of Mycobacterium tuberculosis, important for lipid metabolism/transport, host cell invasion, modulation of host immune response and pathogenicity, is under the transcriptional control of Mce1R. Hence characterizing Mce1R is an important step for novel anti-tuberculosis drug discovery. The present study reports functional and in silico characterization of Mce1R. In this work, we have computationally modeled the structure of Mce1R and have validated the structure by computational and experimental methods. Mce1R has been shown to harbor the canonical VanR-like structure with a flexible N-terminal 'arm', carrying conserved positively charged residues, most likely involved in the operator DNA binding. The mce1R gene has been cloned, expressed, purified and its DNA-binding activity has been measured in vitro. The Kd value for Mce1R-operator DNA interaction has been determined to be 0.35 ± 0.02 µM which implies that Mce1R binds to DNA with moderate affinity compared to the other FCD family of regulators. So far, this is the first report for measuring the DNA-binding affinity of any VanR-type protein. Despite significant sequence similarity at the N-terminal domain, the wHTH motif of Mce1R exhibits poor conservancy of amino acid residues, critical for DNA-binding, thus results in moderate DNA-binding affinity. The N-terminal DNA-binding domain is structurally dynamic while the C-terminal domain showed significant stability and such profile of structural dynamics is most likely to be preserved in the structural orthologs of Mce1R. In addition to this, a cavity has been detected in the C-terminal domain of Mce1R which contains a few conserved residues. Comparison with other FCD family of regulators suggests that most of the conserved residues might be critical for binding to specific ligand. The max pKd value and drug score for the cavity are estimated to be 9.04 and 109 respectively suggesting that the cavity represents a suitable target site for novel anti-tuberculosis drug discovery approaches.

The work deals with an environmentally benign process for the synthesis of silver nanoparticle using Butea monosperma bark extract which is used both as a reducing as well as capping agent at room temperature. The reaction mixture turned brownish yellow after about 24 h and an intense surface plasmon resonance (SPR) band at around 424 nm clearly indicates the formation of silver nanoparticles. Fourier transform-Infrared (FT-IR) spectroscopy showed that the nanoparticles were capped with compounds present in the plant extract. Formation of crystalline fcc silver nanoparticles is analysed by XRD data and the SAED pattern obtained also confirms the crystalline behaviour of the Ag nanoparticles. The size and morphology of these nanoparticles were studied using High Resolution Transmission Electron Microscopy (HRTEM) which showed that the nanoparticles had an average dimension of ∼35 nm. A larger DLS data of ∼98 nm shows the presence of the stabilizer on the nanoparticles surface. The bio-synthesized silver nanoparticles revealed potent antibacterial activity against human bacteria of both Gram types. In addition these biologically synthesized nanoparticles also proved to exhibit excellent cytotoxic effect on human myeloid leukemia cell line, KG-1A with IC50 value of 11.47 μg/mL. Keywords: Butea monosperma, Green route, Silver nanoparticles, Antibacterial, Anticancer

Bile salts carry out a vital bioactive responsibility among the various physiologically important molecules. The use of bile acids and their conjugates in nanoscience is a novel idea, which opens up fascinating prospects and gives rise to various versatile properties. Sodium cholate, a biosurfactant which is environmentally safe, has been used to reduce and stabilize silver nitrate solution. The silver nanostructures thus produced are crystalline and anisotropic in nature and show different types of particle shapes and sizes depending on the reaction conditions including star and wire shapes which have not been reported earlier, by simply varying the reaction conditions. The silver precursor concentration and the ratio of sodium cholate to silver precursor were the key factors which controlled the morphosynthesis. The formation of the silver NPs was monitored using UV-vis spectrophotometry. The transmission electron microscopy (TEM) technique was used to study the morphology of the synthesized NPs. Fourier transform infrared (FT-IR) spectroscopy was used to identify the interaction of sodium cholate with the synthesized NP. The possible mechanistic role of sodium cholate in the reduction and stabilization of silver nanoparticles (Ag NPs) has also been discussed. The obtained Ag NPs exhibit antibacterial and anticancerous activities. The present study also explores the cytotoxic role of Ag NPs in KG-1A (human acute myeloid leukemia) and K562 (human chronic myeloid leukemia) cell lines.

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium-modified montmorillonite [CMMT]) in PBAT matrix was observed by X-ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria. Practical Application Current investigations revealed that PBAT/CMMT/SB nanocomposite film exhibits good barrier properties and antimicrobial activity against food pathogenic bacteria. The PBAT/CMMT/SB nanocomposite film may be a better alternative than pure PBAT film for food packaging application.

Gold and silver-gold alloy nanoparticles with mean diameter of 10nm and narrow size distribution were prepared by reduction of the correspondent metal precursors using aqueous dextran solution which acts as both a reducing and capping agent. The formation of nanoparticles was characterized by UV-vis spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) and dynamic light scattering (DLS). The silver and gold nanoparticles exhibited absorption maxima at 425 and 551 nm respectively; while for the bimetallic Ag-Au alloy appeared 520 nm in between them. TEM images showed monodispersed particles in the range of 8-10nm. The crystallinity of the nanoparticles was assured by XRD analysis. DLS data gave particle size distribution. The dextran stabilized Au nanoparticles used as a colorimetric sensor for detection and estimation of pesticide present in water. The dextran stabilized Ag-Au alloy nanoparticles exhibited interesting antimicrobial activity against bacteria at micromolar concentrations.

Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1 wt% GO.

Nanocomposites of poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP) and sodium montmorillonite (Na + MMT) were prepared by solution mixing and then cast into films. X-ray diffraction analysis and images of transmission electron microscopy establish the formation of PVA/Na + MMT intercalated nanocomposite. Exfoliated and highly intercalated PVA/PVP/Na + MMT nanocomposite formed in the presence of PVP. Inclusion of PVP in PVA/Na + MMT matrix enhances the hydrogen bonding interactions between PVA and Na + MMT and thus increases the mechanical properties and thermal stability of PVA/PVP/Na + MMT nanocomposites compared to PVA/Na + MMT nanocomposite. The interactions between PVA, PVP and Na + MMT were established by the Fourier transform infrared spectroscopy. The moisture absorption tendency of both the PVA and PVA/PVP films reduced after the incorporation of Na + MMT at 75% constant relative humidity. Differential scanning calorimetry studies show that the presence of PVP and Na + MMT both are responsible for reducing the heat of fusion, and crystallinity of PVA. The flow behavior of the PVA, PVA/PVP and its nanocomposite solutions has been also studied. Water vapor permeability of PVA/PVP/Na + MMT composite films decreased in the presence of nanoclay due to increasing tortuous paths for diffusion.

The aim of this investigation was to develop a novel in situ gelling formulation based on poloxamer-407 (PM) for the sustained release of an ophthalmic drug. In an attempt to reduce the concentration of PM without compromising the in situ gelling capability and also to increase the drug release time, xanthan gum (XG) and guar gum (GG) were added into PM to develop different formulations. At concentrations of 18% and above, the PM was able to undergo sol-gel transition below body temperature. It was found that XG and GG at a weight ratio of 3:7 were able to convert PM solution into gel below body temperature at PM concentrations below 18%. Both the in vitro and in vivo studies indicated that the PM with an XG-GG combination had a better ability to retain the drug than PM itself. The results indicated that the developed in situ gelling formulations containing PM with XG-GG may be a better alternative than a conventional eye drop.

Nickel nanoparticles synthesized from NiCl2·6H2O by hydrazine hydrate in mixed solvent of ethanol and water in the presence of hydroxypropylmethylcellulose (HPMC) as protective and stabilizing agents. The morphology and sizes of synthesized Ni nanoparticles were studied by field-emission-scanning-electron microscopy (FESEM). Structural properties of nanoparticles were examined by X-ray diffraction (XRD). The polymer stabilized Ni nanoparticles were characterized by Fourier-transform infrared (FTIR) spectroscopy. The magnetic measurement showed that the resultant Ni nanoparticles were ferromagnetic. Also, the saturation magnetization (MS), remanent magnetization (MR) and coercivity (MR) were observed to increase with decreasing temperature. The results of magnetic characterization showed that the magnetic properties of the HPMC stabilized Ni nanoparticles are quite different from those of the bared Ni nanoparticles. All the observed magnetic properties essentially reflected the very typical nanoparticle type nature. Consequently, the resulting Ni nanoparticles were found to be highly active and recyclable catalyst for Suzuki coupling reactions.

We have proposed a facile green technique for synthesizing silver nanoparticles-based nanofluids at high temperature and pressure using low molecular weight lactulose solution, which is playing the role of a reducing as well as stabilizing agent. The particle/crystallite sizes, morphology, crystallinity of the nanoparticles are characterized using spectroscopic, microscopic, and diffraction techniques. Since the properties of nanofluids are attractive for technological applications, the investigation of their thermal and electrical conductivities is also immensely important. The material shows a significant enhancement of both thermal and electrical conductivities in comparison to the base fluid due to high surface area, enhanced Brownian motion and layering at the liquid–solid interface of the nanofluids. Moreover, these nanofluids offer excellent antimicrobial activities to different gram class bacteria.

Hydroxypropylmethylcellulose (HPMC)/montmorillonite (MMT) nanocomposite films are prepared by solution intercalation method. Mechanical, thermal, moisture absorption, optical clarity and water vapor permeability of HPMC/MMT nanocomposite films are measured. X-ray diffraction (XRD) and transmission electron microscopic (TEM) results establish formation of partially intercalated and partially exfoliated HPMC/MMT nanocomposite films. In presence of MMT, the tensile strength, tensile modulus and elongation at break of HPMC films are improved. The thermal stability of HPMC/MMT nanocomposites is better than pure HPMC. The moisture absorption of HPMC film measured in 75% of constant relative humidity is reduced with loading of MMT. Optical clarity of HPMC film is almost unaffected in presence of MMT. Water vapor permeability of HPMC decreases in presence of nanoclay due to increasing tortuous path for diffusion.

Polyaniline (PANI)-Ag nanocomposites were synthesized by in situ chemical polymerization approach using ammonium persulfate and silver nitrate as oxidant. Characterizations of nanocomposites were done by ultraviolet–visible (UV–vis), Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM). UV–vis, XRD and FTIR analysis established the formation of PANI/Ag nanocomposites and face-centered-cubic phase of silver. PANInanofibers were of average diameter ∼ 30 nm and several micrometers in length. Morphological analysis showed that the spherical-shaped silver nanoparticles decorate the surface of PANI nanofibers. Silver nanoparticles of average diameter ∼ 5–10 nm were observed on the TEM images for the PANI-Ag nanocomposites. Such type of PANI-Ag nanocomposites can be used as bistable switches as well as memory devices. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Gelation temperature of MC was reduced from 59 °C to 54 °C with the addition of 10% PEG. Sodium tartrate (NaT) and sodium citrate (NaC) were added to the MC–PEG solution to further reduce the gelation temperature close to physiological temperature. Different techniques were used to measure the gelation temperature of all formulations. It was observed that NaC was more effective in reducing the gelation temperature of MC–PEG combination than NaT. Environmental scanning electron microscopy (ESEM) images of hydrogels containing NaC and NaT showed that NaC containing hydrogel having an interconnected microporous structure instead of the hollow rod like structure as in the case of NaT containing hydrogel. In vitro drug release studies showed that drug release time increased from 6 to 9 h by only changing the type of salt from NaT to NaC in MC–PEG combination.

In this paper we reported preparation of methylcellulose-silver nanocomposite films by mixing of aqueous solution of methylcellulose with silver nitrate followed by casting. The silver nanoparticles were generated in methylcellulose matrix through reduction and stabilization by methylcellulose. The surface plasmon band at 412 nm indicated the formation of Ag nanoparticles. The MC-Ag nanocomposite films were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR). The X-ray diffraction analysis of synthesized MC-Ag nanocomposite films revealed that metallic silver was present in face centered cubic crystal structure. Average crystallite size of silver nanocrystal was 22.7 nm. The FTIR peaks of as-synthesized MC-Ag nanocomposite fully designated the strong interaction between Ag nanoparticles and MC matrix. Nano-sized silver modified methylcellulose showed enhanced mechanical properties i.e. the introduction of Ag leading to both strengthening and toughening of MC matrix. The methylcellulose-silver nanocomposite films offered excellent antimicrobial activity against various microorganisms.

A simple one-step rapid synthetic route is described for the preparation of silver nanoparticles by reduction of silver nitrate (AgNO3) using aqueous dextran solution which acts as both reducing and capping agent. The formation of silver nanoparticles is assured by characterization with UV-vis spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The absorbance of the silver nanoparticles is observed at 423 nm. The AFM image clearly shows the surface morphology of the well-dispersed silver nanoparticles with size range of 10-60 nm. TEM images show that the nanoparticles are spherical in shape with ∼5-10 nm dimensions. The crystallinity of Ag nanoparticles is assured by XRD analysis. The antimicrobial activity of as synthesized silver nanoparticles is tested against the bacteria, Bacillus subtilis, Bacillus cereus, Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The bacterial growth is inhibited by gradual reduction of the concentration of the silver nanoparticles.

Silver nanoparticles were successfully synthesized from AgNO3 through a reliable, eco-friendly and simple green route using Paederia foetida L. leaf extract as a reducing cum stabilizing agent. UV-Visible Spectroscopy, dynamic light scattering, atomic force microscopy, transmission electron microscopy, and X-ray diffraction analysis were used for characterization of silver nanoparticles. The synthesized silver nanoparticles were spherical in shape with size range of 4–15 nm. The nanoparticles were face-centered cubic crystal structure. The adopted technique for silver nanoparticle synthesis is suitable for large-scale production. The as-prepared silver nanoparticles revealed excellent antibacterial activity against different gram classes of bacteria and would be a promising candidate for various pharmaceutical, biomedical, and environmental applications.

The effect of molecular weight of poly(vinyl alcohol) (PVA) and sodium chloride on the gelation temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ketorolac tromethamine a model ophthalmic drug. Pure MC showed sol-gel transition at 61.2 °C. In order to reduce the gelation temperature of MC and to increase the drug release time, PVA was used. Different techniques such as test tube tilting method, UV-vis spectroscopy, viscometry and rheometry were used to measure gelation temperature of all the binary combinations of MC and PVA. It was observed that the gelation temperature of MC was reduced with the addition of 4% PVA and also the extent of reduction of the gelation temperature of MC was dependent on the molecular weight of PVA. The strong interactions between MC and PVA molecules were established using Fourier transform infrared spectroscopy. To study the in vitro drug release properties of the MC-PVA binary combinations, 6% sodium chloride was used to reduce the gelation temperature further up to physiological temperature. It was observed that the drug release time increased from 5 to 8h with the increase of molecular weight of PVA from 9×10(3) to 1.3×10(5) and this was due to the higher viscosity, better gel strength and greater interactions between the drug and PVA molecules in case of PVA (1.3×10(5)) compared to PVA (9×10(3)). In order to have an idea about the nature of interactions between the functional moieties of the drug and the polymer unit of PVA, a theoretical study was carried out.

Highly crystallized polyaniline (PANI) nanofibers were synthesized by oxidative polymerization of aniline in the presence of sodium alginate as a soft template in HCl and ammonium peroxydisulfate (APS) acting as an oxidizing agent. Sodium alginate, in presence of a protonic acid like HCl, formed hydrogen bonds with anilium ions or oligomers. The formed hydrogen bonds provide the driving force to form PANI nanofibers. The nanofibers were separated from the alginate gel by degelling with ammonium hydroxide and during degelling emeraldine salt was converted into emeraldine base form. The polymerized PANI was characterized using ultraviolet (UV)–visible spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). UV and FTIR spectra showed that the presence of sodium alginate had no effect on the electronic state and backbone structures of the resulting PANI products. It was evident from the XRD analysis that the obtained PANI nanofibers exhibit higher crystalline order. SEM micrographs showed that PANI nanofibers were just like a mat of interwoven twisted nanofibers. After magnification of the SEM image, it was found that most of the nanofibers were interconnected to form ramose structures rather than isolated nanofibers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

A simple and inexpensive, single step synthesis of silver nanoparticles was achieved using poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) both as a reducing and stabilizing agent. The synthetic process was carried out in aqueous solution, making the method versatile and ecofriendly. The synthesized polymer stabilized nanoparticles were stable in water at room temperature without particle aggregation for at least 1 month. The synthesized silver nanoparticles were characterized by UV-visible absorption spectroscopy, X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM), and Fourier transform IR spectroscopy (FTIR). Results showed that Ag-core nanoparticles were coated with PVM/MA shell with thickness of about 5 to 8 nm. The antimicrobial activities of the copolymer (PVM/MA) stabilized silver nanoparticles on various microorganisms were also studied. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significance, mainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process. A homogenous dispersion of organoclay (cetyltrimethylammonium-modified montmorillonite [CMMT]) in PBAT matrix was observed by X-ray diffraction and transmission electron microscopy. PBAT/CMMT nanocomposite film showed higher barrier properties against water and methanol vapor compared to the PBAT film. The release of SB from PBAT and its nanocomposite film was measured and the relevant data were fitted to the Weibull model. The higher values of Weibull's shape factor and scale parameter as corroborated by experimental findings indicated faster rate of SB release from PBAT/CMMT/SB nanocomposite film, when compared to the pristine PBAT film. Bacterial inhibition studies were accomplished against 2 food pathogenic bacteria, Bacillus subtilis and Staphylococcus aureus, by determining the zone of inhibition and corresponding growth profiles. Both bacterial inhibition studies and growth profiles established that PBAT/CMMT/SB demonstrated better antimicrobial activity than PBAT/SB film. Therefore, PBAT/CMMT/SB nanocomposite film can be used for food packaging application as it showed good barrier properties and antimicrobial activity against food pathogenic bacteria.

Poly(butylene adipate-co-terephthalate) (PBAT) nanocomposites films are prepared by a solution intercalation process using natural montmorillonite (MMT) and cetyltrimethylammonium bromide (CTAB)-modified montmorillonite (CMMT). Cation exchange technique has been used for modification of MMT by CTAB and characterized by Fourier transform infrared analysis, thermo-gravimetric analysis, and X-ray diffraction (XRD) studies. CMMT gives better dispersion in the PBAT matrix than MMT and is confirmed by XRD and transmission electron microscopy. Because of better compatibility of CMMT, water vapor transmission rate of PBAT decreases more in the presence of CMMT than MMT. The biodegradability of PBAT and its nanocomposite films are studied in compost and from the morphological analysis it is apparent that the PBAT/CMMT shows a lower biodegradation rate in comparison to the PBAT/MMT. The antimicrobial activity of PBAT and its nanocomposite films is tested by an inhibition zone method. Because of the presence of the quaternary ammonium group of CTAB-modified MMT, PBAT/CMMT nanocomposites show adequate antimicrobial activity. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40079.

Gelation temperature of methylcellulose (MC) can be altered by adding different additives. Pure MC showed sol-gel transition at 60°C. Sodium citrate and sodium tartrate were used alone and in combination to see the effect of individual salt and combination of salts on the gelation temperature of MC. The gelation temperature of all the binary and ternary combinations of MC and salts were measured with different methods such as test tube tilting method (TTM), UV-vis spectroscopy, viscometry, and by rheometer and also the morphology of gels were characterized with the help of environmental scanning electron microscopy (ESEM). It was observed that when 0.1 M sodium citrate (NaC) and 0.1 M sodium tartrate (NaT) were used separately, the gelation temperature of MC was reduced up to 44°C and 47°C respectively but when mixture of NaC and NaT (0.1 (M) NaC and 0.1 (M) (NaT)) were used the gelation temperature was further reduced to 36°C. It was clear from ESEM images that when NaC and NaT were used separately the formation of network was not distinguishable. But, well-connected network structure was observed when a mixture 0.1 M NaC and 0.1 M NaT was used.

The effect of molecular weight of polyethyl- eneglycol (PEG) and sodium chloride (NaCl) on the gela- tion temperature of methylcellulose (MC) was studied with the objective to develop a MC based formulation for sustained delivery of ophthalmic drug. The gelation tem- perature of 1% MC was 60 6 0.40 � C. It was found that the gelation temperature of MC was reduced with the addi- tion of 10% PEG and extent of reduction of gelation tem- perature was depended on the molecular weight of PEG at same PEG concentration of 10%. The gelation tempera- ture of MC was reduced by 10.4 to 5.9 � C with the increas- ing molecular weight of PEG starting from 400 to 20,000 (Mn) depending on the method of determination of gela- tion temperature. To reduce the gelation temperature of MC close to physiological temperature (37 � C), 6% NaCl was added in the different MC-PEG combinations contain- ing different molecular weight of PEG. It was observed that the drug release time increased from 5 to 8 h with the increase in molecular weight of PEG from 400 to 20,000 (Mn) and this was due to the maximum viscosity and gel strength of MC-PEG20000-NaCl ternary combination. V C 2010

Green synthesis of gold nanoparticles (Au NPs) using Abelmoschus esculentus (L.) pulp extract has been elaborately studied and reported here. The Au NPs have been characterized using several techniques. Optical analysis indicates adequate stability of the synthesized Au NPs, while FTIR analyses the fact that phytochemicals present in the Abelmoschus esculentus (L.) pulp extract play the key role in stabilizing the Au NPs. Morphological study shows that the nanoparticles are mostly spherical in shape with an average particle size of ∼14 nm, and these results are comparable with the particle size obtained from XRD. The selected area electron diffraction pattern indicates the crystalline nature of the Au NPs, which is further confirmed from XRD studies. The present study also demonstrates the in vitro efficacy of Au NPs against Jurkat cells. Results show that the IC50 dose of Au NPs is capable of significantly elevating intracellular reactive oxygen species and diminishing mitochondrial membrane potential, indicating the effective involvement of apoptosis in cell death. Furthermore, the synthesized Au NPs show a sufficient degree of antimicrobial activity against different types of bacteria. These results clearly show that the Abelmoschus esculentus (L.) pulp synthesized Au NPs have excellent medicinal applications.

Chiral core–shell nanostructures containing raspberry-like gold cores and well-defined dense organic shells are synthesized by an in situ method using a natural antioxidant catechin as the reducing agent. This method is flexible and enables control over the shell thickness by adjusting the molar ratio of catechin to HAuCl4. Transmission electron microscopic analysis shows the formation of core–shell nanostructures with somewhat raspberry-shaped gold cores. The proposed mechanism explains that catechin reduces Au3+ to metallic Au to gold nanostructures and gets oxidized to different oligomeric products that are adsorbed in situ and assembled through H-bonding and form a thick organic shell around the generated gold nanostructures. Each of these oxidized forms of catechin is well-characterized by FTIR, ESI-MS, and MALDI-TOF-MS spectroscopies. This reaction follows a radical pathway as confirmed by electron paramagnetic resonance spectroscopy. Due to the presence of a compact and dense shell, the rate of gold core dissolution sharply decreases compared to that of the dissolution of monolayer protected Au nanoparticles when etched with KCN solution. The optical activity of the core–shell nanostructure is the result of the interaction between chiral shells and gold cores as observed by circular dichroism (CD) spectroscopy. The chiral core–shell Au nanostructures exhibit a CD band at the plasmon resonance frequency (∼596 nm). Finally, these chiral core–shell nanostructures are used as an effective catalyst in the borohydride reduction of p-nitrophenol.