Characterization of thermo-sensitive hydrogels based on poly(<Emphasis Type=Italic>N</Emphasis>-isopropylacrylamide)/hyaluronic acid

In this study, an hydrogel was synthesized from the monomer N-isopropylacrylamide (NIPA), generating the poly(N-isopropylacrylamide) (PNIPA) and other formulations were synthesized in the presence of 1, 2, and 3% hyaluronic acid (HA) for obtain an interpenetrating polymer network. For all the obtained hydrogels, the thermo-sensitive response was studied since the lower critical solution temperature (LCST) and was analyzed by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and oscillatory rheology at constant frequency as a function of temperature. The LCST transition temperature (Tt onset) was found between 34.4 and 35.5 °C. By scanning electron microscopy (SEM) PNIPA-HA formulations showed a porous morphology. The applicability of the hydrogels as injectable and non-toxic materials was verified, respectively, by rheology results and by cytotoxicity studies through an in vitro test of cell hemolysis on blood agar.     

Modifying <Emphasis Type=Italic>CRI</Emphasis> and <Emphasis Type=Italic>CSR</Emphasis> values of coke

The influence of the following factors on the reactivity CRI and hot strength CSR in industrial coking is studied: eliminating bituminous coal from the coal batch; considerably increasing the coking periods; and significantly reducing the ash content of the batch. Batch composition such that the coke quality meets the needs of export customers (including requirements regarding CRI and CSR) is identified. Sharp deterioration in CRI and CSR is seen when the batch includes coal with high ash basicity and coal concentrate that is heavily contaminated with intermediate products.     

Flavonoids Have Differential Effects on Glucose Absorption in Rats (<Emphasis Type=Italic>Rattus norvegicus</Emphasis>) and American Robins (<Emphasis Type=Italic>Turdis migratorius</Emphasis>)

Mounting evidence suggests that small birds rely largely on non-mediated intestinal absorption of glucose through the paracellular pathway, while non-flying mammals rely on mediated absorption across the enterocyte membranes by using glucose transporters SGLT-1 and GLUT-2. Relying on non-mediated transport of glucose may decrease its absorption rate at low glucose concentrations but may release small birds from the effects of glucose transport inhibitors. We evaluated transport by using flavonoids known to inhibit glucose transport in vitro. Quercetin, isoquercetrin, and phloridzin were tested in rats (Rattus norvegicus) and robins (Turdis migratirius), and naringenin, naringenin-7-glucoside, genistein, epigallocatechin gallate (EGCG), and phloretin were used only in rats. By using a pharmacokinetic approach that involves serial blood collection and area under the curve calculations, we determined the bioavailability of 3-0-methyl D-glucose, the non-metabolized analogue of D-glucose. Six of the eight flavonoids tested in rats significantly decreased the absorption of 3-0-methyl D-glucose, while none of the flavonoids tested in robins significantly decreased the bioavailability of 3-0-methyl D-glucose. We conclude that flavonoids effectively decrease glucose absorption in rats, which rely on mediated absorption of glucose, but that flavonoids do not have an effect in robins, which rely on non-mediated absorption of glucose.     

<Emphasis Type=Italic>Nosema</Emphasis> spp. Infection Alters Pheromone Production in Honey Bees (<Emphasis Type=Italic>Apis mellifera</Emphasis>)

Pheromones in social insects play a key role in the regulation of group homoeostasis. It is well-established that parasites can modify hormone signaling of their host, but less is known about the effect of parasites on pheromone signaling in insect societies. We, thus, tested in honey bees (Apis mellifera) the effect of the widespread parasite Nosema spp. on the production of ethyl oleate (EO), the only identified primer pheromone in honey bee workers. Since environmental stressors like pesticides also can weaken honey bees, we also analyzed the effect of imidacloprid, a neonicotinoid widely used in agriculture, on EO production. We show that, contrary to imidacloprid, Nosema spp. significantly altered EO production. In addition, the level of Nosema infection was correlated positively with the level of EO production. Since EO is involved in the regulation of division of labor among workers, our result suggests that the changes in EO signaling induced by parasitism have the potential to disturb the colony homoeostasis.     

Dispersion polymerization of <Emphasis Type=Italic>N</Emphasis>-vinyl caprolactam in supercritical carbon dioxide

Dispersion polymerization of N-vinyl caprolactam (NVCL) was carried out in supercritical carbon dioxide (scCO₂) using three surfactants. The polymerization was performed in the presence of fluorine-based poly(heptadecafluorodecyl acrylate) (PHDFDA), poly(heptadecafluorodecyl methacrylate) (PHDFDMA) or siloxane-based PDMS-g-pyrrolidonecarboxylic acid (Monasil PCA) as a surfactant. FE-SEM and image analyzer were used to characterize particle morphology, size, and size distribution. When fluorine-based surfactants were used, spherical PVCL particles were obtained. Using Monasil PCA resulted in agglomerated and irregular polymer particles. The effect of concentration of surfactants, initiators, and monomer, and reaction pressure on the particle morphology, average particle size and particle size distribution (PSD) was also investigated with fluorine-based surfactant, PHDFDA or PHDFDMA.     

Synthesis and gas permeability of poly(<Emphasis Type=Italic>p</Emphasis>-phenyleneethynylene)s having bulky alkoxy or alkyl groups

Dipropynylbenzene with branched alkoxy and alkyl groups [CH₃C≡CRC₆H₂RC≡CCH₃, R = 2-methylpropoxy (1a), 3-methylbutoxy (1b), 4-methylpentoxy (1c), cyclohexylmethoxy (1d), 2-ethylhexoxy (1e), 2-octoxy (1f), 2-ethylhexyl (1g), and 2-octyl (1h)] were polymerized with Mo(CO)₆ in the presence of 4-(trifluoromethyl)phenyl to afford poly(2,5-di(alkoxy or alkyl)-p-phenyleneethynylene)s (2a–h). Polymer 2a was insoluble in any solvents, but the other polymers (2b–h) were soluble in common organic solvents. The polymers with relatively long side chains (2e–h) had high molecular weight over 1.6 × 10⁴ and gave free-standing membranes by solution-casting method. The densities of membranes of 2e–h were 0.914–0.998, and their fractional-free volume values were relatively large (0.094–0.158). The oxygen permeability coefficients of membranes of 2e–h were 18.4, 12.7, 4.85, and 19.3 barrers, respectively. It was found that poly(p-phenyleneethynylene) with 2-octyl side groups, which have the branch at the nearest position from main chain, exhibited the highest gas permeability.     

Screening of <Emphasis Type=Italic>Candida utilis</Emphasis> and medium optimization for co-production of <Emphasis Type=Italic>S</Emphasis>-adenosylmethionine and glutathione

An effective S-adenosylmethionine and glutathione enriching yeast mutant of Candida utilis CCTCC M 209298 was first screened from plates containing 0.5 g/L of DL-ethionine by complex mutagenesis with UV and γ-ray in this study. Medium components optimization for enhanced co-production of S-adenosylmethionine and glutathione by C. utilis CCTCC M 209298 was further carried out using response surface methodology. The significant factors influencing S-adenosylmethionine and glutathione co-production were selected by Plackett-Burman design as sucrose, KH₂PO₄ and L-methionine, and Box-Behnken design was applied for further optimization studies. Based on these approaches, the optimized concentrations on medium components for higher co-production of S-adenosylmethionine and glutathione were sucrose 35.4 g/L, (NH₄)₂SO₄ 10 g/L, KH₂PO₄ 12.3 g/L, MgSO₄·7H₂O, 0.05 g/L, CaCl₂ 0.05 g/L and L-methionine 4.6 g/L. The medium optimization by response surface methodology led to a total production of 589.3 mg/L on S-adenosylmethionine and glutathione, which was 2.4-fold increased compared with the medium without optimization.     

Effect of polycarbodiimide on the thermal stability and crystallization of poly(<Emphasis Type=Italic>p</Emphasis>-dioxanone)

A kind of polycarbodiimide (PCD) as a thermal stabilizer was added into poly(p-dixoanone) (PPDO). The effect of PCD on the thermal stability and crystallization of PPDO was investigated by using non-isothermal thermalgravimetry (TG), differential scanning calorimetry (DSC), polarized optical microscopy (POM) and wide angle X-ray diffractometry (WAXD). It has been shown that the addition of PCD can enhance significantly the thermal stability of PPDO. The thermal decomposition temperature of PPDO increases with the increase of the amount of PCD added. The activation energies for non-isothermal thermal degradation estimated by Kissinger method are 160 and 106 kJ mol⁻¹ for PPDO added with 5 wt% PCD and neat PPDO respectively. The results obtained from DSC and POM indicate that PCD plays a role of nucleating agent in the process of crystallization of PPDO. WAXD analyses reveal that the addition of PCD has no effect on the crystal structure of PPDO.     

Porous poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide) gels polymerized in mixed solvents of water and <Emphasis Type="Italic">N,N</Emphasis>-dimethylformamide

The structures of gels polymerized using a mixed solvent that induces cononsolvency during the free radical polymerization were investigated.N,N -isopropylacrylamide (NIPA) gels were polymerized in water and N,N-dimethylformamide (DMF) mixtures. The NIPA gels can have homogeneous/heterogeneous structures depending on the mole fraction of DMF, x_D. The NIPA gel synthesized at x_D = ca. 0.25 was opaque in appearance, and its porous structure was observed by the SEM micrograph; the porous structure is formed as the aggregates of microgels phase-separated due to the cononsolvency. The porous NIPA gels achieve a very rapid shrinking rate in response to the temperature jump, which are desirable for their applications.     

Synthesis of novel single-walled carbon nanotubes/poly (<Emphasis Type=Italic>p</Emphasis>-phenylene benzobisoxazole) nanocomposite

Poly (p-phenylene benzobisoxazole) (PBO) fibers are some of the strongest organic polymer fibers. However, the introduction of single-walled carbon nanotubes (SWNT) into the PBO backbone might lead to improvements in their alignment and physical properties. Therefore, SWNT was cut and functionalized by three oxidative cutting methods. After cutting, three different types of SWNT were obtained. Furthermore, copolymerization of SWNTs with PBO polymer was successfully carried out in a mixed solvent of polyphosphoric acid and methanesulfonic acid. The SWNTs were homogeneously distributed throughout the films of copolymerized products, as determined by Raman spectroscopy. The benzoxazole moieties could be formed between the carboxyl of SWNTs and o-aminophenol derivatives of PBO polymer. The length of SWNTs affected the dispersion and reaction activity. Short SWNTs could react with the PBO polymer more easily and form more covalent bonds.     

<Emphasis Type=Italic>Jatropha</Emphasis> Diterpenes: a Review

Terpenes are the largest group of phytochemicals that exhibit diverse functions in mediating antagonistic and beneficial interactions in, and among, organisms. For many years the abundance and distribution of terpenoid compounds in plants have benefitted both nature and human civilization. Jatropha species, belonging to the family Euphorbiaceae, are a rich source of terpenoid compounds. Among the terpenes, diterpenoid compounds have dominated the research area in Jatropha species with respect to their novel chemical structures and medicinal values. The present review describes the chemistry and biological activities of an array of Jatropha diterpenes. The diterpenes isolated from Jatropha species belongs to rhamnofolane, daphnane, lathyrane, tigliane, dinorditerpene, deoxy preussomerin and pimarane skeletal structures. Among the 68 diterpenes collated in this review, the biological activity of compounds varied distinctly—the majority of the diterpenes exhibited cytotoxic, antitumor and antimicrobial activities in vitro. To name a few, jatrophone, spruceanol and jatrophatrione exhibited antitumor properties against P338 lymphocytic leukemia and japodagrol against KB carcinoma cells. Whereas, curcusone B exhibited anti-invasive effects against cholangiocarcinoma cells. The phorbol esters (Jatropha factor C1–C6) and Jatropherol exhibited insect deterrent/cytotoxic properties. Many diterpenes (jatrophalactam, faveline derivatives, multifolone, curcusone, jatrophone derivatives etc.) showed in-vitro cytotoxic activity, while japodagrin, jatrogrossidione derivatives and jatropholone derivatives exhibited antimicrobial activities. Jatropha diterpenoids having a wide spectrum of bioactivity could form lead compounds or could be used as templates for the synthesis of new compounds with better biological activity for utilization in the pharmaceutical industries.     

Swelling and mechanical behavior of charged poly(<Emphasis Type="Italic">N</Emphasis>-isopropylmethacrylamide) and poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide) networks in water/ethanol mixtures. Cononsolvency effect

Summary Swelling and mechanical behavior of negatively (ionic comonomer-sodium methacrylate) and positively (ionic comonomer-(2-acrylamidoethyl)trimethyl ammonium chloride) charged networks of poly(N-isopropylmethacrylamide) (PIPMAm) and poly(N-isopropylacrylamide) (PIPAAm) was investigated in water/ethanol mixtures at room temperature. Strong cononsolvency effect was observed for uncharged and negatively charged gels of both systems; while for neat solvents high degree of swelling Q was observed, for solvent mixtures pronounced minima in swelling were found. Swelling minima are connected with the coil-to-globule transition of network chains and their characteristic parameters-concentration of ethanol at the minimum, c_eth,m, and corresponding swelling degree, Q_m, were determined. With increasing amount of negatively charged ionic comonomer the minimum in swelling shifts to higher c_eth,m values and Q_m increase. On the other hand, positively charged networks of both systems exhibit roughly constant Q values practically independent of solvent mixtures compositions. For all four systems it was found that mechanical behavior is predominantly determined by the degree of swelling regardless of charge concentration.     

Molecular-hydrodynamic study of poly(<Emphasis Type="Italic">N</Emphasis>-methyl-<Emphasis Type="Italic">N</Emphasis>-vinylacetamide) macromolecules

High-velocity sedimentation, translational isothermal diffusion, and viscometry in H₂O and DMF are used to investigate the samples and fractions of poly(N-methyl-N-vinylacetamide) synthesized by free-radical polymerization and fractionated in a chloroform-diethyl ether system. Molecular masses M and the Mark-Kuhn-Houwink-Sakurada relations are obtained for the fractions in the molecular mass range M × 10⁻³ = 3.5−540.0. The negative temperature coefficient of intrinsic viscosity is revealed for both solvents. The length of the Kuhn statistical segment and the hydrodynamic diameter of poly(N-methyl-N-vinylacetamide) macromolecules are estimated; the hydrodynamic volumes occupied by water-soluble poly(N-methyl-N-vinylacetamide), poly(1-vinyl-2-pyrrolidone), poly(vinylformamide), and pullulan molecules are compared.     

Physico-Chemical Analysis,NMR Spectroscopy and Gas Chromatographic Studies of <Emphasis Type=Italic>Jatropha</Emphasis><Emphasis Type=Italic>curcas</Emphasis> L. Germplasm

A systematic collection of Jatropha curcas germplasm was carried out from five distinct ecogeographic zones of peninsular India in 2008. This involved recording passport data, documentation of important plant traits in situ, ecogeographic parameters and assessment of variability in 82 accessions. Extraction of oil was done by the Soxhlet method which gave an average yield of 38%. Oil content of collected accessions was determined by nuclear magnetic resonance and Soxhlet extraction. Oil variability ranged from 45.5% in JC-8 to 11.5% in JC-30. The level of unsaturated fatty acid ranged from 85% in JC-57 to 75.5% in JC-10. Saturated fatty acids ranged from 24% in JC-43 to 15% in JC-54, the oxidative stability index was highest at 2.1 in JC-30 and lowest at 0.68 in JC-17. The seed weight was greatest in JC-8 and the lowest in JC-30. This paper provides information that will facilitate the selection of promising accessions for genetic enhancement of Jatropha germplasm through conventional breeding.     

Inactivation of Baculovirus by Isoflavonoids on Chickpea (<Emphasis Type=Italic>Cicer arietinum</Emphasis>) Leaf Surfaces Reduces the Efficacy of Nucleopolyhedrovirus Against <Emphasis Type=Italic>Helicoverpa armigera</Emphasis>

Biological pesticides based on nucleopolyhedroviruses (NPVs) can provide an effective and environmentally benign alternative to synthetic chemicals. On some crops, however, the efficacy and persistence of NPVs is known to be reduced by plant specific factors. The present study investigated the efficacy of Helicoverpa armigera NPV (HearNPV) for control of H. armigera larvae, and showed that chickpea reduced the infectivity of virus occlusion bodies (OBs) exposed to the leaf surface of chickpea for at least 1 h. The degree of inactivation was greater on chickpea than that previously reported on cotton, and the mode of action is different from that of cotton. The effect was observed for larvae that consumed OBs on chickpea leaves, but it also occurred when OBs were removed after exposure to plants and inoculated onto artificial diet, indicating that inhibition was leaf surface-related and permanent. Despite their profuse exudation from trichomes on chickpea leaves and their low pH, organic acids—primarily oxalic and malic acid—caused no inhibition. When HearNPV was incubated with biochanin A and sissotrin, however, two minor constituents of chickpea leaf extracts, OB activity was reduced significantly. These two isoflavonoids increased in concentration by up to 3 times within 1 h of spraying the virus suspension onto the plants and also when spraying only the carrier, indicating induction was in response to spraying and not a specific response to the HearNPV. Although inactivation by the isoflavonoids did not account completely for the level of effect recorded on whole plants, this work constitutes evidence for a novel mechanism of NPV inactivation in legumes. Expanding the use of biological pesticides on legume crops will be dependent upon the development of suitable formulations for OBs to overcome plant secondary chemical effects.