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Substrates Used (substrate + used)
Selected AbstractsMulticolor Emission on Prepatterned Substrates Using a Single Dye Species,ADVANCED MATERIALS, Issue 16 2007W. Hu A new strategy for realizing patterned surfaces with different emission colors is demonstrated. This approach relies on the gas-phase deposition of dye molecules onto solid substrates that are prepatterned by nanoimprint lithography (see figure). Only a single molecular species is involved. Thus, the observed color change and corresponding spectral shift in the emission properties depends on the substrate used and can be tuned by surface engineering. [source] Ink-jet Printing and Microwave Sintering of Conductive Silver Tracks,ADVANCED MATERIALS, Issue 16 2006J. Perelaer Conductive silver tracks on a polyimide substrate (see figure) are prepared by using microwave radiation to sinter silver nanoparticles printed on the substrate. This method shortens the necessary sintering time dramatically and is independent of the substrate used. Since the polymer substrate is virtually transparent to microwave radiation, a negligible amount of energy is absorbed by the substrate, whereas the conducting silver nanoparticles, with a high dielectric loss factor, strongly absorb the microwaves. [source] Influence of natural and controlled fermentations on , -galactosides, antinutrients and protein digestibility of beans (Phaseolus vulgaris L.)INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2008Emire Admassu Shimelis Summary The influence of natural fermentation (NF) and controlled fermentation (CF) in diminishing the content of antinutrients, , -galactosides and increments in in vitro protein digestibility was investigated. The dry bean (Phaseolus vulgaris) flour was the substrate used in this research study. A decrease in raffinose oligosaccharide, antinutritional components and pH was observed in both types of fermentation. The natural lactic fermentation of ground beans produced significant increase (P < 0.05) in protein digestibility. For all varieties of beans, raffinose concentration reduced significantly to an undetectable level after 96 h of NF. CF did not have any significant effect on the reduction of the , -galactosides content of the flours during fermentation. NF is an inexpensive method by which consumers can obtain good-quality protein. Both types of fermentation diminish antinutrients and improve the nutritional value of the bean flour, and indicate the potential to use bean flour as an ingredient for fabricated foods. [source] Co-operative actions and degradation analysis of purified xylan-degrading enzymes from Thermomonospora fusca BD25 on oat-spelt xylanJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2003M. Tuncer Abstract Aims: To determine and quantify the products from the degradation of xylan by a range of purified xylan-degrading enzymes, endoxylanase, , -xylosidase and , - l -arabinofuranosidase produced extracellularly by Thermomonospora fusca BD25. Methods and Results: The amounts of reducing sugars released from oat-spelt xylan by the actions of endoxylanase, , -xylosidase and , - l -arabinofuranosidase were equal to 28·1, 4·6 and 7% hydrolysis (as xylose equivalents) of the substrate used, respectively. However, addition of , -xylosidase and , - l -arabinofuranosidase preparation to endoxylanase significantly enhanced (70 and 20% respectively) the action of endoxylanase on the substrate. The combination of purified endoxylanase, , -xylosidase and , - l -arabinofuranosidase preparations produced a greater sugar yield (58·6% hydrolysis) and enhanced the total reducing sugar yield by around 50%. The main xylooligosaccharide products released using the action of endoxylanase alone on oat-spelt xylan were identified as xylobiose and xylopentose. , - l -Arabinofuranosidase was able to release arabinose and xylobiose from oat-spelt xylan. In the presence of all three purified enzymes the hydrolysis products of oat-spelt xylan were mainly xylose, arabinose and substituted xylotetrose with lesser amount of substituted xylotriose. Conclusions: The addition of the , -xylosidase and , - l -arabinofuranosidase enzymes to purified xylanases more than doubled the degradation of xylan from 28 to 58% of the total substrate with xylose and arabinose being the major sugars produced. Significance and Impact of the Study: The results highlight the role of xylan de-branching enzymes in the degradation of xylan and suggest that the use of enzyme cocktails may significantly improve the hydrolysis of xylan in industrial processes. [source] Tacrolimus is a class II low-solubility high-permeability drug: The effect of P-glycoprotein efflux on regional permeability of tacrolimus in ratsJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 3 2002Shigeki Tamura Abstract The objective of this study is to investigate the role of P-glycoprotein (P-gp), a membrane efflux pump associated with multidrug resistance (MDR) and a known substrate for tacrolimus, in determining the regional intestinal permeability of tacrolimus in rats. Thus, isolated segments of rat jejunum, ileum, or colon were perfused with tacrolimus solutions containing polyethoxylated hydrogenated castor oil 60 surfactant, and with or without verapamil, a P-gp substrate used to reverse the MDR phenotype. The results indicated that the intrinsic permeability of tacrolimus in the jejunum, calculated on the basis of the concentration of non-micellized free tacrolimus, was quite high (,,1.4,×,10,4 cm/s). The apparent permeability (Papp) in the jejunum was unaffected by the presence of verapamil; however, the Papp in the ileum and the colon increased significantly in the presence of verapamil and were similar to the values observed in the jejunum. The results suggest that systemic absorption of tacrolimus from the gastrointestinal tract could be significantly affected by P-gp efflux mechanisms. It is also possible that differences in P-gp function at various intestinal sites in a subject or at a given intestinal site in various subjects could lead to large intra- and interindividual variability in bioavailability of tacrolimus following oral administration. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:719,729, 2002 [source] A mutagenic analysis of the RNase mechanism of the bacterial Kid toxin by mass spectrometryFEBS JOURNAL, Issue 17 2009Elizabeth Diago-Navarro Kid, the toxin of the parD (kis, kid) maintenance system of plasmid R1, is an endoribonuclease that preferentially cleaves RNA at the 5, of A in the core sequence 5,-UA(A/C)-3,. A model of the Kid toxin interacting with the uncleavable mimetic 5,-AdUACA-3, is available. To evaluate this model, a significant collection of mutants in some of the key residues proposed to be involved in RNA binding (T46, A55, T69 and R85) or RNA cleavage (R73, D75 and H17) were analysed by mass spectrometry in RNA binding and cleavage assays. A pair of substrates, 5,-AUACA-3,, and its uncleavable mimetic 5,-AdUACA-3,, used to establish the model and structure of the Kid,RNA complex, were used in both the RNA cleavage and binding assays. A second RNA substrate, 5,-UUACU-3, efficiently cleaved by Kid both in vivo and in vitro, was also used in the cleavage assays. Compared with the wild-type protein, mutations in the residues of the catalytic site abolished RNA cleavage without substantially altering RNA binding. Mutations in residues proposed to be involved in RNA binding show reduced binding efficiency and a corresponding decrease in RNA cleavage efficiency. The cleavage profiles of the different mutants were similar with the two substrates used, but RNA cleavage required much lower protein concentrations when the 5,-UUACU-3, substrate was used. Protein synthesis and growth assays are consistent with there being a correlation between the RNase activity of Kid and its inhibitory potential. These results give important support to the available models of Kid RNase and the Kid,RNA complex. [source] Variability in the origin of carbon substrates for bacterial communities in mangrove sedimentsFEMS MICROBIOLOGY ECOLOGY, Issue 2 2004Steven Bouillon Abstract Organic carbon in mangrove sediments originates from both local sources (mangroves, microphytobenthos) and tidal inputs (e.g. phytoplankton, seagrass-derived material). The relative inputs of these sources may vary strongly, both within and between different mangrove sites. We combined elemental (TOC/TN) and bulk ,13C analysis on sediment cores from various mangrove sites with ,13C data of bacteria-specific phospholipid fatty acids (PLFA) in order to identify the dominant carbon substrates used by in situ bacterial communities. ,13C values of each of these markers showed a range of 10% or more across the different sites and sampling depths, but generally followed the ,13C trend observed in bulk organic carbon. Several sediment cores show a strong vertical gradient in PLFA ,13C, suggesting a selectivity for algal-derived carbon in the surface layers. Our data demonstrate that the origin of bacterial carbon substrates varies widely across different mangrove sites, and imply that data on mineralization of organic matter cannot be directly incorporated in ecosystem carbon budgets without an estimation of the contribution of various sources. [source] Micropore modification in InPPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 11 2008D. Nohavica Abstract The structural features and optical properties of microporous InP substrates used for epitaxial overgrowth of thin films have been investigated. Both crystalographically oriented (CO) and current line oriented (CLO) pore networks were created by electrochemical dissolution. Heat treatment of the InP pores converted them into microcavities maintaining the same crystallographic direction. The effect of phosphorus vapour pressure was proved to be crucial for the microcavity formation, since it influences the mass transport during heat treatment. Electron microscopy and photoluminescence experiments revealed the absence of significant extended defects, both after the pore and cavities formation. The capability of improved structural quality homo- and hetero-epitaxial overgrown films on the porous InP, was also demonstrated. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Lipase-Catalyzed Acyl Exchange of Soybean Phosphatidylcholine in n -Hexane: A Critical Evaluation of Both Acyl Incorporation and Product RecoveryBIOTECHNOLOGY PROGRESS, Issue 2 2005Anders F. Vikbjerg Lipase-catalyzed acidolysis was examined for the production of structured phospholipids in a hexane system. In a practical operation of the reaction system, the formation of lyso-phospholipids from hydrolysis is often a serious problem, as demonstrated from previous studies. A clear elucidation of the issue and optimization of the system are essential for the practical applications in reality. The effects of enzyme dosage, reaction temperature, solvent amount, reaction time, and substrate ratio were optimized in terms of the acyl incorporation, which led to the products, and lyso-phospholipids formed by hydrolysis, which led to the low yields. The biocatalyst used was the commercial immobilized lipase Lipozyme TL IM and substrates used were phosphatidylcholine (PC) from soybean and caprylic acid. A response surface design was used to evaluate the influence of selected parameters and their relationships on the incorporation of caprylic acid and the corresponding recovery of PC. Incorporation of fatty acids increased with increasing enzyme dosage, reaction temperature, solvent amount, reaction time, and substrate ratio. Enzyme dosage had the most significant effect on the incorporation, followed by reaction time, reaction temperature, solvent amount, and substrate ratio. However the parameters had also a negative influence on the PC recovery. Solvent amount had the most negative effect on recovery, followed by enzyme dosage, temperature, and reaction time. Individually substrate ratio had no significant effect on the PC recovery. Interactions were observed between different parameters. On the basis of the models, the reaction was optimized for the maximum incorporation and maximum PC recovery. With all of the considerations, the optimal conditions are recommended as enzyme dosage 29%, reaction time 50 h, temperature 54 °C, substrate ratio 15 mol/mol caprylic acid/PC, and 5 mL of hexane per 3 g substrate. No additional water is necessary. Under these conditions, an incorporation of caprylic acid up to 46% and recovery of PC up to 60% can be obtained from the prediction. The prediction was confirmed from the verification experiments. [source] Industrial Potential of Organic Solvent Tolerant BacteriaBIOTECHNOLOGY PROGRESS, Issue 3 2004Yogita N. Sardessai Most bacteria and their enzymes are destroyed or inactivated in the presence of organic solvents. Organic solvent tolerant bacteria are a relatively novel group of extremophilic microorganisms that combat these destructive effects and thrive in the presence of high concentrations of organic solvents as a result of various adaptations. These bacteria are being explored for their potential in industrial and environmental biotechnology, since their enzymes retain activity in the presence of toxic solvents. This property could be exploited to carry out bioremediation and biocatalysis in the presence of an organic phase. Because a large number of substrates used in industrial chemistry, such as steroids, are water-insoluble, their bioconversion rates are affected by poor dissolution in water. This problem can be overcome by carrying out the process in a biphasic organic-aqueous fermentation system, wherein the substrate is dissolved in the organic phase and provided to cells present in the aqueous phase. In bioprocessing of fine chemicals such as cis -diols and epoxides using such cultures, organic solvents can be used to extract a toxic product from the aqueous phase, thereby improving the efficiency of the process. Bacterial strains reported to grow on and utilize saturated concentrations of organic solvents such as toluene can revolutionize the removal of such pollutants. It is now known that enzymes display striking new properties in the presence of organic solvents. The role of solvent-stable enzymes in nonaqueous biocatalysis needs to be explored and could result in novel applications. [source] Kinetics and Film Properties of Boron Nitride Derived from Trimethoxyborane/Ammonia by Chemical Vapor Deposition,CHEMICAL VAPOR DEPOSITION, Issue 6 2004H. Strakov Abstract The kinetics of the CVD of boron nitride from trimethoxyborane (TMOB) and ammonia (NH3) under atmospheric pressure was investigated by varying the following process parameters: temperature, residence time of the reactants, molar fraction of TMOB, and the NH3/TMOB ratio, ,. A kinetic power law equation was derived, that describes the experimental results with good accuracy. The reaction order with respect to TMOB is found to be 0.9 and ,,0.2 with respect to NH3. Between 800,°C and 950,°C, the deposition rate is controlled by the surface reaction kinetics with apparent activation energy of 115.1,kJ,mol,1. The deposited BN films were characterized by IR spectroscopy, Raman spectroscopy, and X-ray diffraction (XRD). The microstructure of the deposits depends on the nature of the substrates used. Turbostratic boron nitride (t-BN) was deposited on graphite, and hexagonal boron nitride (h-BN) on alumina substrates. X-ray photoelectron spectroscopy (XPS) analyses show nearly stoichiometric BN films for deposition temperatures in the range 850,950,°C for high amounts of ammonia (100,<,,,<,150) in the feed gas. [source] | ||||||||||||||||