Bioderived cellulose fibre-guar gum grafted poly (N, N'-dimethylacrylamide) polymer network for controlled release of metformin hydrochloride.

An interpenetrating polymer network (IPN) of areca cellulose and guar gum grafted with poly (N, N'-dimethylacrylamide) was made by microwave irradiation technique. N, N-methylenebisacrylamide (MBA) was used as the crosslinking agent. The network polymer was characterised using Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), Powder X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM). The chemical interaction between the drug and the polymer was studied using Differential Scanning Calorimetry (DSC). The swelling of the gel was measured under different pH conditions and the swelling parameters were evaluated. The gel was loaded with an anti-diabetic drug, Metformin Hydrochloride, and the in vitro drug release was studied in gastric and intestinal conditions. The results indicated complete release of the drug in 6 h under pH 1.2 and in 10 h under pH 7.4. The kinetic analysis of release data indicated the drug release to follow Higuchi's model. The release exponent "n" of Korsmeyer-Peppas model was found to be >0.45 indicating the drug diffusion to be a non-Fickian process.

Graphene oxide functionalized chitosan-magnetite nanocomposite for removal of Cu(II) and Cr(VI) from waste water.

A novel adsorbent material for removal of metal ions from aqueous solution was made by modifying chitosan. The schiff base prepared from reaction of chitosan with 3-(p-anisyl)-4-formylsydnone was further functionalized with graphene oxide. Finally Fe3O4 nanoparticles were incorporated into the modified chitosan to obtain a novel adsorbent material. The nanocomposite made was characterized using FTIR, TGA, SEM, EDS and XRD techniques and evaluated for adsorptive removal of Cu(II) and Cr(VI) ions from aqueous solutions. The maximum adsorption capacities of the adsorbent for Cu(II) and Cr(VI) ions were found to be 111.11 and 142.85 mgg-1 respectively. The adsorption data fitted well with Langmuir isotherm model and followed pseudo second order kinetic model. Thermodynamic parameters indicated the adsorption to be spontaneous and endothermic. The desorption studies revealed the efficient recovery of adsorbate species and possible reusability of the adsorbent material.

Identification and Characterization of a Large Effect QTL from Oryza glumaepatula Revealed Pi68(t) as Putative Candidate Gene for Rice Blast Resistance.

BACKGROUND: Field resistance is often effective and durable as compared to vertical resistance. The introgression line (INGR15002) derived from O. glumaepatula has proven broad spectrum field resistance for both leaf and neck blast. RESULTS: Quantitative Trait Loci (QTL) analysis of INGR15002, led to the identification of two major QTL - qBL3 contributing about 34% and 32% phenotypic variance towards leaf and neck blast resistance, respectively and qBL7 contributing about 25% of phenotypic variance for leaf blast. Further, qBL3 was fine mapped, narrowed down to 300 kb region and a linked SNP maker was identified. By combining mapping with microarray analysis, a candidate gene, Os03g0281466 (malectin-serine threonine kinase), was identified in the fine mapped region and named as Pi68(t). The nucleotide variations in the coding as well as upstream region of the gene was identified through cloning and sequence analysis of Pi68(t) alleles. These significant variations led to the non-synonymous changes in the protein as well as variations (presence/absence) in four important motifs (W-box element; MYC element; TCP element; BIHD1OS) at promoter region those are associated with resistance and susceptible reactions. The effect of qBL3 was validated by its introgression into BPT5204 (susceptible variety) through marker-assisted selection and progeny exhibiting resistance to both leaf and neck blast was identified. Further, the utility of linked markers of Pi68(t) in the blast breeding programs was demonstrated in elite germplasm lines. CONCLUSIONS: This is the first report on the identification and characterization of major effect QTL from O. glumaepatula, which led to the identification of a putative candidate gene, Pi68(t), which confers field resistance to leaf as well as neck blast in rice.

Modified chitosan gel incorporated with magnetic nanoparticle for removal of Cu(II) and Cr(VI) from aqueous solution.

A novel adsorbent material for removal of metal ion from aqueous solution was made by modification of chitosan. Schiff base prepared from reaction of chitosan with 3-methyl-1-phenyl-5-(piperidin-1-yl)-1H-pyrazole-4-carbaldehyde was crosslinked with epichlorohydrin to form a crosslinked gel. Fe3O4 nanoparticles were incorporated into the modified chitosan gel to obtain a magnetic adsorbent material. The magnetic nanocomposite thus obtained was characterized using FTIR, TGA, SEM, EDS and XRD techniques and evaluated for adsorptive removal of Cu(II) and Cr(VI) ions from aqueous solutions. The maximum adsorption capacity of the adsorbent for Cu(II) and Cr(VI) ions was found to be 90.90 and 83.33 mg g-1 respectively. The adsorption data fitted well with Langmuir isotherm model and the pseudo-second order kinetic model. Thermodynamic parameters indicated the adsorption to be spontaneous and endothermic. The desorption studies revealed the efficient recovery of adsorbate species and possible reusability of the adsorbent material.

Development of MART for the Rapid Production of Nanostructured Lipid Carriers Loaded with All-Trans Retinoic Acid for Dermal Delivery.

All-trans retinoic acid (ATRA) has been regarded as a wonder drug for many dermatological complications; however, its application is limited due to the extreme irritation, and toxicity seen once it has sufficiently concentrated into the bloodstream from the skin. Thus, the present study was aimed to increase the entrapment of ATRA and minimize its transdermal permeation. ATRA incorporated within nanostructured lipid carriers (NLCs) were produced by a green and facile thin lipid-film based microwave-assisted rapid technique (MART). The optimization was carried out using the response surface methodology (RSM)-driven artificial neural network (ANN) coupled with genetic algorithm (GA). The liquid lipid and surfactants were seen to play a very crucial role culminating in the particle size (< 70 nm), zeta potential (< - 32 mV), and entrapment of ATRA (> 98%). ANN-GA-optimized NLCs required a minimal quantity of the surfactants, formed within 2 min and were stable for 1 year at different storage conditions. The optimized NLC-loaded creams showed a skin retention (ex vivo) to an extent of 87.42% with no detectable drug in the receptor fluid (24 h) in comparison to the marketed cream which released 47.32% (12 h) of ATRA. The results were in good correlation with the in vivo skin deposition studies. The NLCs were biocompatible and non-skin irritant based on the primary irritation index. In conclusion, the NLCs were seen to have a very high potential in overcoming the drawbacks of ATRA for dermal delivery and could be produced conveniently by the MART.

Synthesis and metal ion adsorption characteristics of graphene oxide incorporated chitosan Schiff base.

The work reports the development of a novel adsorbent material based on modified chitosan for removal of Cu (II) and Cr (VI) ions from aqueous solution. Heterocyclic modification of chitosan has been achieved by the reaction of chitosan with 5-chloro-3-methyl-1-phenyl-1H-pyrazole-4-carbaldehyde resulting in a Schiff base. This was further modified by incorporation of graphene oxide at the C6 position through ester linkage. This modification results in increase in the number of binding sites like donor nitrogens, OH and COOH groups. The modified polymer was characterized using FTIR, TGA, SEM, EDS and XRD techniques. The adsorption capacity exhibited by the modified chitosan towards Cu (II) and Cr (VI) were 111.11 and 76.92 mg/g respectively which is a significant improvement compared to chitosan. The adsorption data fitted well with Langmuir isotherm model and pseudo second order kinetic model. The thermodynamic analysis of adsorption data indicated endothermic and spontaneous nature of adsorption. A high desorption of over 80% was achieved for Cu (II) in acidic solution and for Cr (VI) in basic solution indicating efficient recovery of adsorbate species.

Synthesis of pyrazole-based Schiff bases of Chitosan: Evaluation of antimicrobial activity.

In this work, a novel series of Schiff base has been reported by the reaction of Chitosan with different substituted pyrazole-4-carbaldehydes in acidic media. The synthesized compounds were characterized by Fourier-transform infrared spectroscopy (FTIR), thermo gravimetric analysis (TGA), X-ray diffraction (XRD) and 13C NMR techniques. Chitosan and the Schiff bases were compared for their antimicrobial activity against the bacteria; Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, Escherichia coli and a fungi, Candida albicans. The results indicated stronger inhibitory effect of the Schiff bases on these microorganisms compared to Chitosan and the extent of inhibition varied with the nature of substitution.

RAPD assisted selection of black gram (Vigna mungo L. Hepper) towards the development of multiple disease resistant germplasm.

Black gram (Vigna mungo L. Hepper), is an extensively studied food crop which is affected by many abiotic and biotic factors, especially diseases. The yield potential of Black gram is shallow due to lack of genetic variability and biotic stress susceptibility. Core biotic stress factors include mung bean yellow mosaic virus (MYMV), urdbean leaf crinkle virus (UCLV), wilt (Fusarium oxysporum) and powdery mildew (Erysiphe polygoni DC). Although many studies determine resistant varieties to a particular disease, however, it is often complimented by low yield and susceptibility to other diseases. Hence, this study focuses on investigating the genetic relationships among three varieties and nine accessions of black gram having disease resistance to previously described diseases and susceptibility using random amplified polymorphic deoxyribonucleic acid (RAPD) markers. A total of 33 RAPD primers were used for diversity analysis and yielded 206 fragments. Number of amplified fragments ranged from two (OPN-1) to 13 (OPF-1). The highest similarity coefficient was observed between IC-145202 and IC-164118 (0.921), while lowest similarity was between PU-31 and IC-145202 (0.572). The genetic diversity obtained in this study along with disease analysis suggests PU31as a useful variety for the development of markers linked to MYMV, UCLV, wilt and powdery mildew resistance by marker-assisted back cross breeding and facilitates the production of crosses with multiple disease resistance.

Gellan gum-graft-polyaniline--An electrical conducting biopolymer.

Grafting of polyaniline (PANI) on to gellan gum (GG) was carried out in the presence of catalytic amount of ammonium peroxydisulfate (APS) as oxidant/initiator under mild acidic conditions by microwave irradiation technique. The grafting condition was optimized by varying the microwave power, exposure time and the composition of the reaction mixture. The graft copolymer GG-g-PANI was characterized by FTIR, TGA, UV/vis, (1)H NMR and SEM techniques. The characteristic peaks at 1506, 1462, 1070 and 830 cm(-1) in the IR spectrum and signals at 7.3, 7.2, 7.1 and 4.0 δ in the (1)H NMR spectrum confirms the grafting process. The TGA data reveals GG-g-PANI to be thermally less stable than GG. The optimum grafting was observed when the reaction mixture containing 0.066 mmol APS, 0.1M aniline, 1M hydrochloric acid and 0.1g/dL GG was exposed to 80 W microwave power for 40s. The DC and AC conductivity of the GG-g-PANI were measured using the 'Two-point probe' method based on which the dielectric properties were evaluated. GG-g-PANI exhibited appreciable electrical conductivity, which increased with the extent of grafting. The results indicate threefold increase in DC conductivity of graft copolymer as compared to GG.

Novel stimuli responsive gellan gum-graft-poly(DMAEMA) hydrogel as adsorbent for anionic dye.

In this study, gellan gum-grafted-poly((2-dimethylamino) ethyl methacrylate) (GG-g-poly(DMAEMA)) hydrogel was made by free radical polymerization in aqueous media employing microwave irradiation technique. Ammonium persulfate (APS)/N,N,N',N'-tetramethylethylenediamine (TMEDA) were used as initiator-accelerator pair. N,N'-methylenebisacrylamide (MBA) has been used as crosslinker. The gel was characterized by FTIR, XRD, TGA, DSC and SEM techniques. The characteristic peaks at 1724, 2630, 1147, 1650 and 1535cm(-1) in the IR spectrum confirms grafting and gel formation. The TGA data reveals that synthesized gels were thermally more stable than gellan gum. The XRD studies confirm the crystalline nature of the synthesized material. Swelling behaviour of the hydrogel under different temperatures and pH conditions was investigated. The results indicated drastic changes in swelling around pH 7.0 and 50°C. The gels were evaluated as an adsorbent to remove an anionic dye, methyl orange (MO), from aqueous solution. The pH conditions for maximum adsorption were optimized, the adsorption data is observed to fit best to the Freundlich isotherm model and the maximum adsorption capacity was found to be 25.8mgg(-1). The kinetic analysis revealed a second-order adsorption process. The thermodynamic parameters showed the adsorption to be exothermic and non-spontaneous at high temperatures.

Synthesis of ethylenediamine modified chitosan microspheres for removal of divalent and hexavalent ions.

Ethylenediamine modified chitosan was obtained in the form of microspheres by chemical crosslinking with gluteraldehyde and evaluated for the effective removal of metal ions. The present modification results in additional nitrogen centers which function as potential binding sites and the microsphere form enhances the specific surface area during adsorption of metal ions. The adsorbent was used in batch experiments to evaluate the adsorption of Cu(II), Zn(II), Pb(II) and Cr(VI) in a individual metal salt solutions. The samples exhibited highest affinity for Cu(II) and least for Cr(VI) ions. The adsorption data were interpreted based on Langmuir and Freundlich isotherm models. The maximum adsorption capacity obtained from Langmuir model is 60.9 mg g(-1). The modified microspheres can be regenerated with high efficiency, suggesting that this adsorbent is satisfactory to reuse.

Synthesis of ethylenediamine modified chitosan and evaluation for removal of divalent metal ions.

Selective modification of chitosan has been achieved by incorporating ethylene-1,2-diamine molecule in a regioselective manner using N-phthaloylchitosan and chloro-6-deoxy N-phthaloylchitosan as precursors. The present modification results in additional nitrogen centres which function as potential binding sites during adsorption of metal ions. The derivative ethylene-1,2-diamine-6-deoxy-chitosan and its pthaloylated precursor have been evaluated for divalent metal ion removal. The former is found to have higher capacity for adsorption due to the presence of additional NH2 group. The samples exhibited highest affinity for Cu and least for Zn. About 80% of the adsorbed metal ions could be stripped in a solution of pH 1.2. The interaction between acidic metal centres and basic nitrogen centres on surface of the adsorbent appears to govern adsorption. Intrachain and interchain co-ordinate bonding involving NH and NH2 groups is proposed to be the mechanism of formation of metal-adsorbent complex. The adsorption process is described by Langmuir model.

Preparation of substituted quaternized arylfuran chitosan derivatives and their antimicrobial activity.

Heterocyclic modification of chitosan has been achieved through the formation of a Schiff base intermediate by the reaction of chitosan with substituted arylfurfural. The Schiff bases were further reacted with 10% sodium borohydride followed by reaction with methyl iodide to get the quaternized products. The formation of the Schiff bases and quaternized derivatives has been confirmed by elemental analysis, FTIR, (1)H NMR and UV-vis spectroscopy. The compounds are also characterized by thermo-gravimetric analysis. The parent compound and quaternized derivatives were compared for their antibacterial and antifungal activity. The results indicated that quaternized derivatives possess better inhibitory property than chitosan. Further this study confirms that heterocyclic aromatic substituent containing 'Cl' and 'NO2' are effective in enhancing the antimicrobial activity of Chitosan.

A study of interaction of cationic dyes with anionic polyelectrolytes.

The interactions of Acridine Orange with Sodium Alginate and Pinacyanol Chloride with Heparin have been investigated by spectrophotometric method. The polymers induce metachromasy in the dye as evidenced from the considerable blue shift in the absorption maxima of the corresponding dyes. The interaction constant and thermodynamic parameters of polymer-dye interactions have been determined. The effect of additives such as alcohols, and urea on the reversal of metachromasy has been studied. The data has been used to determine the stability of the metachromatic complex and the nature of binding. The thermodynamic parameters of interaction revealed that binding between Acridine Orange and Sodium Alginate involved only electrostatic forces while that between Pinacyanol Chloride involved both electrostatic and hydrophobic forces. The reversal studies using surfactants indicated the involvement of both electrostatic and hydrophobic forces in binding. Based on the results it can be concluded that Pinacyanol Chloride is more effective inducing metachromasy than Acridine Orange.

A comparative study of polyelectrolyte-dye interactions.

The interaction of Azure B with sodium alginate and heparin in aqueous solution has been studied by spectrophotometric method. Absorbance of Azure B at 645 nm decreases and a new band appeared at 545 nm and at 556 nm respectively which indicated that a new metachromatic complex formed. A linear decrease in absorbance is noted. It was found that sodium alginate is more effective than heparin in decreasing the absorbance of Azure B at 645 nm. The stoichiometry of sodium alginate or heparin with Azure B was determined by spectrophotometry. The results suggested that the interaction between Azure B with sodium alginate or heparin was a result of electrostatic forces and the difference between heparin and sodium alginate were attributed to the different negative charge number on repetitive disaccharides unit. Studies on the effect of alcohol or urea indicated that sodium alginate and heparin interacted with the aggregates of Azure B. Thermodynamic parameters of interaction has been evaluated to determine the stability of the metachromatic complex. The effect of surfactants on reversal of metachromasy has also been studied.

A series of substituted (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-phenylprop-2-en-1-ones.

In the molecular structures of a series of substituted chalcones, namely (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-phenylprop-2-en-1-one, C21H15FO2, (I), (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-(4-fluorophenyl)prop-2-en-1-one, C21H14F2O2, (II), (2E)-1-(4-chlorophenyl)-3-(2-fluoro-4-phenoxyphenyl)prop-2-en-1-one, C21H14ClFO2, (III), (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-(4-methylphenyl)prop-2-en-1-one, C22H17FO2, (IV), and (2E)-3-(2-fluoro-4-phenoxyphenyl)-1-(4-methoxyphenyl)prop-2-en-1-one, C22H17FO3, (V), the configuration of the keto group with respect to the olefinic double bond is s-cis. The molecules pack utilizing weak C-H...O and C-H...pi intermolecular contacts. Identical packing motifs involving C-H...O interactions, forming both chains and dimers, along with C-H...pi dimers and pi-pi aromatic interactions are observed in the fluoro, chloro and methyl derivatives.

Four substituted pyrazolines.

In the title compounds 5-(3-fluoro-4-phenoxyphenyl)-1,3-biphenyl-4,5-dihydro-1H-pyrazole, C27H21FN2O, (I), 3-(4-chlorophenyl)-5-(3-fluoro-4-phenoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole, C27H20ClFN2O, (II), 5-(3-fluoro-4-phenoxyphenyl)-3-(4-methylphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole, C28H23FN2O, (III), and 5-(3-fluoro-4-phenoxyphenyl)-3-(4-methoxyphenyl)-1-phenyl-4,5-dihydro-1H-pyrazole, C28H23FN2O2, (IV), the five-membered pyrazole ring exists in an envelope conformation. The crystal structure of (I) has three independent C-H...pi intermolecular interactions. In (II), an intermolecular C-Cl...pi contact is present, forming molecular chains. Replacement of this chloro group in (II) by a methyl group yields an isomorphic crystal structure, (III).

4-(4-fluoro-3-phenoxyphenyl)-6-(4-fluorophenyl)-2-oxo-1,2-dihydropyridine-3-carbonitrile and the 6-(4-methylphenyl)- analogue.

The crystal structures of the title compounds, viz. C24H14F2N2O2, (I), and C25H17FN2O2, (II), respectively, have been determined in order to unravel the role of an ordered F atom in generating stable supramolecular assemblies. On changing the substitution from fluorine to a methyl group, C-H...F interactions are replaced by C-H...pi interactions, revealing the importance of such weak interactions when present alongside N-H...O and C-H...O hydrogen bonds. The dihedral angle between the planes of the 4-fluorophenyl ring and the pyridine ring is 26.8 (1) degrees in (I), while that between the planes of the 4-methylphenyl and pyridine rings is 29.5 (1) degrees in (II).