Swelling behaviors and mechanical properties of polymer gel/poly(<Emphasis Type="Italic">N</Emphasis>-vinyl-2-pyrrolidone) complexes

The contraction of poly(acrylic acid-co-butyl methacrylate) (P(AA-co-BMA)) gel induced by complexation with linear Poly(N-vinyl-2-pyrrolidone) (PVP) is quite different from that of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) gel. The dynamic mechanic properties vary greatly between complexed and uncomplexed networks. It was found that the concentration of PVP has a strong effect on the complexation with P(AA-co-BMA) gel and the dynamic mechanic properties of the P(AA-co-BMA)/PVP complexes.     

Effect of Ni in palladium <Emphasis Type="Italic">β</Emphasis>-zeolite on hydroisomerization of <Emphasis Type="Italic">n</Emphasis>-decane

Bifunctional catalysts containing (0.1–0.5 wt%) Nickel and 0.1 wt% of Pd supported on H-β zeolite were synthesized by incipient wetness impregnation method and characterized by XRD, TEM, XPS, TPD and TPR techniques. The catalytic activity of Ni containing and Ni free Pd/H-β Catalysts was studied, and it was found that Ni up to a threshold value (0.3 wt% on β) produced increased the n-decane conversion and isomerization selectivity. When Ni content exceeds the threshold value, the conversion increases but isomerized products decrease. Moreover, Ni containing Pd/H-β showed increased sustainability and favored the protonated cyclopropane (PCP) intermediate mechanism in n-decane isomerization. The catalyst containing 0.3 wt% Ni 0.1 wt% Pd is adjudged as one performing better than other catalysts studied because of the isomerized mixture from it shows better octane number.     

Production of 14-Oxo-<Emphasis Type="Italic">cis</Emphasis>-11-eicosenoic Acid from Lesquerolic Acid by <Emphasis Type="Italic">Sphingobacterium multivorum</Emphasis> NRRL B-23212

The objective of this study was to explore the extent of microbial conversion of lesquerolic acid (14-hydroxy-cis-11-eicosenoic acid; LQA) by whole cell catalysis and to identify the newly converted products. Among compost isolates including NRRL strains B-23212 (Sphingobacterium multivorum), B-23213 (Acinetobacter sp.), B-23257 (Enterobacter cloacae B), B-23259 (Escherichia sp.) and B-23260 (Pseudomonas aeruginosa) the S. multivorum strain was the only microorganism that converted LQA to produce a new product identified as 14-oxo-cis-11-eicosenoic acid by GC-MS and NMR analyses. The conversion yield was 47.4% in 48 h at 200 rpm and 28°C in small shake flask experiments. In comparison, both Acinetobacter and Pseudomonas strains failed to convert LQA to major new products but used LQA apparently as an energy source during fermentation. For structural analysis, 6.88 g of 14-oxo-cis-11-eicosenoic acid was produced from converting 11 g LQA (a 62% yield) in 72 h at 200 rpm and 28 °C in Fernbach flasks using 18-h-old NRRL B-23212 cultures and an improved medium that also contained EDTA and glycerol in lieu of glucose as carbon source. NRRL B-23212 was further identified by 16S rRNA gene sequence analysis as a unique strain of S. multivorum. Therefore, S. multivorum NRRL B-23212 possesses an enzymatic activity presumably a secondary alcohol dehydrogenase for converting LQA to produce 14-oxo-cis-11-eicosenoic acid, a first report that demonstrates the functional modification of LQA by whole cell catalysis.     

Common Variants of <Emphasis Type="Italic">ABCB4</Emphasis> and <Emphasis Type="Italic">ABCB11</Emphasis> and Plasma Lipid Levels: A Study in Sib Pairs with Gallstones,and Controls

Most epidemiological surveys have confirmed the association of low HDL-cholesterol and high triglyceride levels with cholesterol gallstones. Our objective was to analyze the relationship between plasma lipid levels and common polymorphisms of ABCB11 (encoding the bile salt export pump, BSEP) and ABCB4 (encoding the phospholipid transporter into bile, MDR3) genes. Plasma lipids were measured in 108 index patients of sib pairs with gallstones and in 260 controls. Using PCR-based assays with 5′-nuclease and fluorescence detection (TaqMan), the ABCB11 coding SNP p.A444V and four haplotype-tagging SNPs covering the ABCB4 gene (c.504C > T, c.711T > A, p.R652G, rs31653 in intron 26) were genotyped. Plasma lipids were compared in carriers of the common versus rare allele of these polymorphisms using Student’s t test and Pearson’s correlation. BMI and triglyceride levels were higher and HDL-cholesterol levels were lower in affected siblings than in controls. Among cases, triglyceride and cholesterol levels were higher in carriers of the common versus rare (hetero/homozygous carriers) allele of the SNPs p.A444V of ABCB11 and C.504C > T of ABCB4. HDL-cholesterol was lower in carriers of the common allele of rs31653. In controls, significant differences of cholesterol and HDL-cholesterol levels were found in carriers of ABCB4 polymorphisms. Our results do not support the hypothesis of a link between ABCB4 and ABCB11 polymorphisms, lithogenic dyslipidemia, and gallstone risk.     

Characterization of the Seed Oil and Meal from <Emphasis Type="Italic">Monechma ciliatum</Emphasis> and <Emphasis Type="Italic">Prunus mahaleb</Emphasis> Seeds

The oil and meal from Monechma ciliatum (black mahlab) and Prunus mahaleb (white mahlab) seeds were characterized for their physicochemical properties. The oil content was found to be 30.95 and 13.15% in white and black mahlab seeds, respectively. The refractive indices of white mahlab oil (WMO) and black mahlab oil (BMO) were 1.475 and 1.470, and specific gravities were 0.8511 and 0.8167 g/cm³, respectively. Saponification values were 184.23 and 180.3 mg KOH/g, peroxide values were 2.54 and 4.43 meq/kg, and unsaponifiable matter was 0.92 and 0.66%, respectively. The major fatty acids were palmitic 4.5%, stearic 16.0%, oleic 47.3%, and linoleic 31.4% in BMO, while in WMO they were palmitic 5.7%, oleic 45.0%, and linoleic acid 47.0%. A moderate amount of tocopherols were found at 45.2 and 28.5 mg/100 g in BMO and WMO, respectively. Protein content was found to be 21% in black and 28% in white mahlab seeds. The total amount of amino acids in black and white mahlab seeds was found to be 783.3 and 1,223.2 mg/g N, respectively. The concentration (on ppm dry-weight basis) of major elements (Ca, K, and Mg) and of minor elements (Al, Pb Ni, Mn, Cu, Cr, Co, and Fe) was also determined in the meals.     

Predicting coke quality on the basis of <Emphasis Type="Italic">CSR</Emphasis> and <Emphasis Type="Italic">CRI</Emphasis>: A review

Analysis of the regression equations proposed for the prediction of coke quality on the basis of CSR and CRI shows that some equations with relatively high correlation coefficients produce results inconsistent with experimental data and therefore require refinement. Equations that include characteristics calculated from the chemical composition of the ash and the physical constants of the oxides present (the molecular mass, the actual density, the melting point) lead to large errors and hence cannot be recommended.     

NMR Metabolomics of Thrips (<Emphasis Type="Italic">Frankliniella occidentalis</Emphasis>) Resistance in <Emphasis Type="Italic">Senecio</Emphasis> Hybrids

Western flower thrips (Frankliniella occidentalis) has become a key insect pest of agricultural and horticultural crops worldwide. Little is known about host plant resistance to thrips. In this study, we investigated thrips resistance in F ₂ hybrids of Senecio jacobaea and Senecio aquaticus. We identified thrips-resistant hybrids applying three different bioassays. Subsequently, we compared the metabolomic profiles of these hybrids applying nuclear magnetic resonance spectroscopy (NMR). The new developments of NMR facilitate a wide range coverage of the metabolome. This makes NMR especially suitable if there is no a priori knowledge of the compounds related to herbivore resistance and allows a holistic approach analyzing different chemical compounds simultaneously. We show that the metabolomes of thrips-resistant and -susceptible hybrids differed considerably. Thrips-resistant hybrids contained higher amounts of the pyrrolizidine alkaloids (PA), jacobine, and jaconine, especially in younger leaves. Also, a flavanoid, kaempferol glucoside, accumulated in the resistant plants. Both PAs and kaempferol are known for their inhibitory effect on herbivores. In resistant and susceptible F ₂ hybrids, young leaves showed less thrips damage than old leaves. Consistent with the optimal plant defense theory, young leaves contained increased levels of primary metabolites such as sucrose, raffinose, and stachyose, but also accumulated jacaranone as a secondary plant defense compound. Our results prove NMR as a promising tool to identify different metabolites involved in herbivore resistance. It constitutes a significant advance in the study of plant–insect relationships, providing key information on the implementation of herbivore resistance breeding strategies in plants. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Immobilization of <Emphasis Type="Italic">α</Emphasis>-amylase from <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> on developed support using microbial transglutaminase

α-amylase from Bacillus licheniformis was successfully immobilized on developed support, which was prepared by coating a chitosan-casein film on silica, at 20 °C, pH 6.0 for 5 hr with microbial transglutaminase (MTG) as the cross-linking factor. The optimal support was obtained when 1% chitosan and 1% casein were used in the coating mixture. The optimal condition for immobilization catalyzed by MTG was confined to be at MTG concentration of 15 U/mL, pH 6.0, reacting for 6 hr at 20 °C. The highest specific activity of immobilized α-amylase was achieved as 236 U/g. After immobilization, the obtained enzyme showed broader pH profile and maintained more than 70% of the original activity after 20 reuses.     

<Emphasis Type="Italic">trans</Emphasis> Fatty Acid Content of Canadian Margarines Prior to Mandatory <Emphasis Type="Italic">trans</Emphasis> Fat Labelling

Dietary trans fatty acids (TFA) are of major concern because of their adverse effects on blood lipid levels and coronary heart disease. In Canada, margarines were significant sources of TFA during the 1980s and 1990s. However, this is expected to change with increased public awareness over their adverse health effects and the introduction of new legislature to include TFA content on the Nutritional Facts table of food labels. In this study, the TFA content of the top-selling 29 Canadian margarines, which represented 96.3% of the market share, was determined by capillary gas-liquid chromatography in order to assess the influence of regulatory development during the 3-year transition period between the announcement of new food labelling regulations in Canada that require mandatory declaration of the trans fat content in most pre-packaged foods in January 2003 and its enforcement on 12 December 2005. The 29 margarines included 15 tub margarines made from non-hydrogenated vegetable oils (NHVO-tub margarines), 11 tub margarines made from partially hydrogenated vegetable oils (PHVO-tub margarines) and three print margarines, which were also made from partially hydrogenated vegetable oils (PHVO-print margarines). The 15 NHVO tub-margarines accounted for 71% of the total margarine market share and generally contained less than 2% TFA (mean value 0.9 ± 0.3% of total fatty acids). The mean total TFA contents of PHVO-tub margarines and PHVO-print margarines, were 20.0 ± 4.5% and 39.6 ± 3.5%, and their market shares were 19.3 and 6.0%, respectively. Although during the last 10 years, increasing number of soft tub margarines that contained very little trans fats have been made available in Canada, the PHVO-tub- and -print margarines still contain high levels of trans fats similar to those margarines that were sold in the 1990s. The market share data suggest that the margarines prepared using NHVO and containing almost no TFA were preferred by Canadians over those margarines prepared using PHVO, even before the mandatory declaration of TFA content came into effect on 12 December 2005.     

Photoluminescence of Amorphous Multilayer Structures <Emphasis Type="Italic">a</Emphasis>-C:H/<Emphasis Type="Italic">a</Emphasis>-Si:H

The optical absorption edge and the photoluminescence spectra of amorphous hydrogenated diamond-like carbon (a-C:H) films are investigated in the temperature range 4.2–900 K. Low-dimensional multilayer structures a-C:H/a-Si:H, in which a-C:H with an optical band gap E _g = 4.5 eV is used as a barrier, are prepared for the first time. It is found that amorphous hydrogenated silicon (a-Si:H) films with a thickness d < 100 Å exhibit quantum-confinement effects. Analysis of the photoluminescence spectra and the optical absorption edge of the a-Si:H films shows that the structures a-C:H/a-Si:H have a sharp interface and that charge carriers in the a-Si:H film undergo quantization.Original Russian Text Copyright © 2005 by Fizika i Khimiya Stekla, Babaev, Kamilov, Sultanov, Askhabov.     

Reaction selectivity of <Emphasis Type="Italic">rhizomucor miehei</Emphasis> lipase as influenced by monoacylation of <Emphasis Type="Italic">sn</Emphasis>-glycerol

Reaction selectivities were determined in multicompetitive reactions mediated by Rhizomucor miehei (RM) lipase at water activity of 0.19 in hexane. Saturated FA (C4–C18 even chain) and oleic acid (C18∶1) were reacted with a single alcohol, glycerol, or α-or β-MAG containing C4, C10, C16, or C18∶1 individually as alcohol cosubstrate. Similar patterns of broad FA selectivity toward C8–C18 FA were generally observed for esterification into specific acylglycerol (AG) pools with the different α/β-CX-MAG cosubstrates. Exceptions were enrichment of C18 in the MAG pool with α-C16-MAG substrate, and a general suppression of C4/C6 FA reactivity and a specific discrimination toward >C8 FA incorporation into the TAG pool, both for reactions with α-C10- and α-C16-MAG. RM lipase selectivity toward MAG was in descending order: β-C18∶1-MAG>α/β-C4-MAG∼β-C10-MAG∼β-C16-MAG>α-C18∶1-MAG >α-C10-MAG∼α-C16-MAG. Selectivity in channeling CX of the original CX-MAG substrates into higher AG species was in descending order: α-C10-MAG∼α-C16-MAG>β-C10-MAGβ-C16-MAG>α-C18∶1-MAG>β-C18∶1-MAG∼ α/β-C4-MAG. Aside from their characteristic FA selectivity, Burkholderia cepacia (PS-30) and RM lipases behaved similarly in terms of MAG selectivity as well as a general conservation of FA selectivity throughout the sequential steps of TAG assembly from FA and glycerol for processes designed to yield specifically structured TAG.     

Protoplast from <Emphasis Type="Italic">β</Emphasis>-carotene-producing fungus <Emphasis Type="Italic">Blakeslea trispora</Emphasis>: Preparation,regeneration and validation

The effects of key parameters on the preparation and regeneration of protoplast from the β-carotene-producing fungus Blakeslea trispora were discussed in this paper, including the combination of various enzymes, mycelial age, digesting time and temperature, pH value, osmotic stabilizers, pretreatment, culture medium and culture method. Under the condition of mixed enzymes in osmotic stabilizer (0.6 M NaCl) combined with 2% lysozyme, 3% cellulase and 3% snailase, the highest protoplast yield, as high as 7.48×106 protoplasts/mL, was obtained when mycelial age was 60 h at pH 5.0–6.0 with digesting for 14–16 h at 28 °C. After purification of the obtained protoplasts, they were regenerated in PDA regenerative medium using bilayer plate culture method. To validate the usability of the protoplasts, a novel plasmid with green fluorescent protein (GFP) was used in transformation for easy visual observation. The results showed that the protoplasts prepared by the optimized method were active and applicable in further gene manipulation experiments. This work was presented at 13 ^th YABEC symposium held at Seoul, Korea, October 20–22, 2007.     

Temperature programmed desorption of <Emphasis Type="Italic">n</Emphasis>-hexane and <Emphasis Type="Italic">n</Emphasis>-heptane from MFI and FAU zeolites

TPD studies of n-hexane and n-heptane from NaX, Y and ZSM-5 (Na⁺ or H⁺ exchanged) in the experimental system with a TCD detector were performed, using pure He or He/n-alkane mixture as a carrier gas. The TPD profiles with one desorption peak for Y and two peaks for ZSM-5, measured using He/hydrocarbon mixture, were similar to the previously reported equilibrated thermodesorption results. TPD profiles were accurately fitted with a model based on the equilibrium control of the desorption and the adsorption functions derived from the Langmuir or dual site Langmuir isotherms.     

Еlectrochemical hydriding/dehydriding of nanocrystalline Mg<Subscript>2−<Emphasis Type="Italic">x</Emphasis></Subscript>Sn<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>Ni (<Emphasis Type="Italic">x</Emphasis> = 0, 0.1, 0.3)

The electrochemical hydriding/dehydriding under galvanostatic conditions of nanostructured Mg_2-x Sn _x Ni (x = 0,0.1,0.3) were studied at different temperatures in the range 28–45 °C. The discharge capacity, cycle life and electrochemical impedance of the alloys were found to depend on the presence of Sn. Tin decreases the maximum electrochemical capacity, but essentially improves the cycle life of Mg₂Ni. Intensive corrosion of surface Mg was found to take place during the first 2–3 charge/discharge cycles to a much larger extent for Mg₂Ni, compared to the tin containing alloys. Sn decreases the electron density around the Mg atoms and therefore impedes magnesium oxidation. It was also found that Sn hampers charge transfer but reduces the hydrogen diffusion resistance in Mg₂Ni based alloys.     

Soil bio-functioning under <Emphasis Type="Italic">Acacia nilotica</Emphasis> var. <Emphasis Type="Italic">tomentosa</Emphasis> protected forest along the Senegal River

Acacia nilotica var. tomentosa trees from the Diarra protected forest located in the Senegal River valley were identified for the assessment of both biological nitrogen fixation, using the natural abundance method, and soil bio-functioning parameters (nodulation, root biomass, total microbial biomass, and potential N mineralization). The presence and the genetic diversity of indigenous rhizobia nodulating A. nilotica var. tomentosa was also investigated, taking into account distance from the trunk (0, 1, 2, and 3 m) and depth (0–25, 25–50, and 50–75 cm). Surprisingly, no nodules on the trees root systems were found, whereas under laboratory conditions the presence of indigenous rhizobia nodulating A. nilotica var. tomentosa was demonstrated in the analyzed soils (90% of the nodules harvested on the trapped plants were occupied by the same Inter-Genic Spacer (IGS) group, IGS1). There was no significant influence of trees and/or depth on total microbial biomass and potentials of nitrogen mineralization. Some assumptions were formulated on the possible combined effect of flooding, which usually occurs annually during 4–7 months, and the clayey soils in the Diara forests. Although a deeply natural nodulation of A. nilotica var. tomentosa trees by indigenous rhizobia is not excluded, but it still remains to be demonstrated.     

Towards a Phosgene-Free Synthesis of Aryl Isocyanates: Alcoholysis of <Emphasis Type="Italic">N-</Emphasis>phenylurea to <Emphasis Type="Italic">N-</Emphasis>phenyl-<Emphasis Type="Italic">O-</Emphasis>methyl Carbamate Promoted by Basic Metal Oxide Nanoparticles and Organocatalysts

There is an urgent need to develop new processes for the synthesis of polyurethanes and polycarbonates different from the current technology based on the use of phosgene. In the case of polyurethanes, the reaction of phosgene with aromatic amines renders N-aryl isocyanates that are the co-monomers for these polymers. In the search for a phosgene-free process for the synthesis of N-aryl isocyanates, N-aryl carbamates could play a key role of synthetic precursors. N-Aryl carbamates can be prepared in turn by alcoholysis of N-aryl ureas. Herein, we compare the catalytic activity of three homogeneous catalysts and four heterogeneous metal oxides for the methanolysis of N-phenylurea as a model probe for other aromatic ureas. In the present work we have carried out this reaction in the presence of KOH, 1,8-diaminonaphthalene (a protonic sponge), a dimeric phosphazene (strong, neutral soluble base) and nanometric ZnO, MgO, CaO and a mixed Mg/Al metal oxide derived from hydrotalcite calcination. Besides the target N-phenyl O-methyl carbamate, N-phenyl isocyanate and undesired aniline were also formed. It was observed that using KOH and diaminonaphthalene, aniline was formed preferentially with respect to the desired carbamate. In contrast, dimeric phosphazene forms the target N-phenyl O-methyl carbamate with 90% selectivity at 99% N-phenylurea conversion. In the case of the metal oxides, the best-performing solid catalyst was CaO that exhibits similar activity (99% N-phenylurea conversion) and carbamate selectivity (89%) as phosphazene. CaO performs as a truly heterogeneous catalyst and could be reused for a second run with only a 4 and 2% decrease in conversion and selectivity, respectively.