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Same Substrate (same + substrate)
Selected AbstractsMicrobial Community Dynamics of a Continuous Mesophilic Anaerobic Biogas Digester Fed with Sugar Beet SilageENGINEERING IN LIFE SCIENCES (ELECTRONIC), Issue 4 2008B. Demirel Abstract The aim of the study was to investigate the long-term fermentation of an extremely sour substrate without any addition of manure. In the future, the limitation of manure and therefore the anaerobic digestion of silage with a very low buffering capacity will be an increasing general bottleneck for energy production from renewable biomass. During the mesophilic anaerobic digestion of sugar beet silage (without top and leaves) as the sole substrate (without any addition of manure), which had an extreme low pH of around 3.3, the highest specific gas production rate (spec. GPR) of 0.72,L/g volatile solids (VS),d was achieved at a hydraulic retention time (HRT) of 25,days compared to an organic loading rate (OLR) of 3.97,g VS/L,d at a pH of around 6.80. The methane (CH4) content of the digester ranged between 58 and 67,%, with an average of 63,%. The use of a new charge of substrate (a new harvest of the same substrate) with higher phosphate content improved the performance of the biogas digester significantly. The change of the substrate charge also seemed to affect the methanogenic population dynamics positively, thus improving the reactor performance. Using a new substrate charge, a further decrease in the HRT from 25 to 15,days did not influence the digester performance and did not seem to affect the structure of the methanogenic population significantly. However, a decrease in the HRT affected the size of the methanogenic population adversely. The lower spec. GPR of 0.54,L/g,VS,d attained on day,15 of the HRT could be attributed to a lower size of methanogenic population present in the anaerobic digester during this stage of the process. Furthermore, since sugar beet silage is a relatively poor substrate, in terms of the buffering capacity and the availability of nutrients, an external supply of buffering agents and nutrients is a prerequisite for a safe and stable digester operation. [source] The crystal structure of a xyloglucan-specific endo-,-1,4-glucanase from Geotrichum sp.FEBS JOURNAL, Issue 18 2009M128 xyloglucanase reveals a key amino acid residue for substrate specificity Geotrichum sp. M128 possesses two xyloglucan-specific glycoside hydrolases belonging to family 74, xyloglucan-specific endo-,-1,4-glucanase (XEG) and oligoxyloglucan reducing-end-specific cellobiohydrolase (OXG-RCBH). Despite their similar amino acid sequences (48% identity), their modes of action and substrate specificities are distinct. XEG catalyzes the hydrolysis of xyloglucan polysaccharides in endo mode, while OXG-RCBH acts on xyloglucan oligosaccharides at the reducing end in exo mode. Here, we determined the crystal structure of XEG at 2.5 Å resolution, and compared it to a previously determined structure of OXG-RCBH. For the most part, the amino acid residues that interact with substrate are conserved between the two enzymes. However, there are notable differences at subsite positions ,1 and +2. OXG-RCBH has a loop around the +2 site that blocks one end of the active site cleft, which accounts for its exo mode of action. In contrast, XEG lacks a corresponding loop at this site, thereby allowing binding to the middle of the main chain of the substrate. At the ,1 site in OXG-RCBH, Asn488 interacts with the xylose side chain of the substrate, whereas the ,1 site is occupied by Tyr457 in XEG. To confirm the contribution of this residue to substrate specificity, Tyr457 was substituted by Gly in XEG. The wild-type XEG cleaved the oligoxyloglucan at a specific site; the Y457G variant cleaved the same substrate, but at various sites. Together, the absence of a loop in the cleft and the presence of bulky Tyr457 determine the substrate specificity of XEG. [source] Genetic polymorphisms of chitotriosidase in Caucasian children with bronchial asthmaINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2006S. Bierbaum Summary In humans, two types of chitinases have been identified: chitotriosidase I (CHIT1) and acid mammalian chitinase (AMCase). They are enzymes that cleave chitin, a polysaccharide contained in many different human parasites. So far, only little is known about their function in human and especially in human diseases. Recently we have described association of polymorphisms of AMCase with bronchial asthma in a pediatric population. In this study we were interested in whether CHIT1 is also involved in the genetics of asthma. The amino acid variants Gly102Ser and Ala442Gly, as well as a 24 bp duplication within CHIT1, were typed by means of restriction fragment length polymorphisms on 322 children with asthma and 270 randomly chosen adult controls. Statistical analyses made use of the Armitage's trend test; haplotypes were calculated by famhap and fastehplus. The amino acid variants showed no association with bronchial asthma. The 24 bp duplication, previously shown to completely demolish CHIT1 activity, was also evenly distributed between asthmatics and controls. Finally, the haplotype showed no association with the disease. We conclude from our results that CHIT1 does not play a major role in the development of bronchial asthma in Caucasian children. The results might also imply that the two human chitinases that have been identified so far have quite distinct functions in human diseases even though they have the same substrate. [source] Miniaturized planar ferrite junction circulator in the form of substrate-integrated waveguideINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2008Wenquan Che Abstract The theoretical analysis and engineering implementation of the planar substrate-integrated waveguide (SIW) ferrite junction circulator have been proposed in this article. The ferrite junction circulator is implemented in the form of SIW, taking the features of low profile, small volume and easy integration with other planar circuits. The design strategies of the device have been introduced, including the design consideration of the microstrip transition. One C-band prototype of SIW ferrite junction circulator has been fabricated and measured. The experimental results indicate the bandwidth is about 33% at ,15 dB isolation and the maximum isolation is near 40 dB. However, the insertion loss is a little big, owing to the imperfect dielectric material and fabrication inaccuracy. The SIW ferrite junction circulator and the microstrip transition are integrated into a same substrate, resulting in a very compact planar ferrite junction circulator and indicating potential applications in integrated communication and radar systems. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2008. [source] A compact substrate integrated waveguide H-plane horn antenna with dielectric arc lensINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 5 2007Wenquan Che Abstract An H-plane horn antenna constructed into SIW (substrate integrated waveguide) is proposed. It has a dielectric arc lens for better directivity and a simple microstrip transition as feed. The horn, the lens and the transition share the same substrate. The resulting formula from optical principles shows that the suitable dielectric lens can improve the directivity of the antenna significantly. A prototype was fabricated; the antenna size is 39.175 × 14 × 2 mm3. The frequency band is from 25.5 to 28.5 GHz. The measured gain of this antenna is about 9 dB; the bandwidth, at 10 dB return loss, is over 12%. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007. [source] Miniaturized antenna using half-mode substrate integrated waveguide structureMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008Cuilin Zhong Abstract An X-band miniaturized antenna which uses half-mode substrate integrated waveguide structure is designed. We analyzed the electromagnetic field using the cavity model and the electromotive force method. The input impedance, simulated and experimental results of return loss, resonant frequency, and radiation patterns are presented. Its performances are as same as those of the corresponding microstrip antenna, but its size is half of the microstrip antenna. This planar structure can be integrated on the same substrate with other components such as filter and amplifier, and it can also be used to easily form antenna arrays. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3214,3218, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23911 [source] 5.8 GHz orientation-specific extruded-fin heatsink antennas for 3D RF system integrationMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008Lance Covert Abstract In high-power RF transmitter applications, the heatsink can be used as an antenna for improved antenna performance and increased integration. Extruded-fin heatsink antennas designed at 5.8 GHz are orientation-specific when the heatsink base replaces the patch of a patch antenna. In this case, the orientation of the fins with respect to the patch edges plays a significant role in the antenna performance and must be considered. The results show that the heatsink antenna using a lossy, low-cost FR4 substrate increases the bandwidth from 3.1 to 17.6% and radiation efficiency from 62 to 87% compared with the patch antenna on the same substrate. Also, the orientation has a significant effect on the directivity, gain, and radiation pattern. By combining two functions into one structure, the component count in a system is reduced and the antenna performance can be improved. © Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1826,1831, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23478 [source] Dual-frequency antenna for RFID tags with complementary characteristicMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2007Jieh-Sen Kuo Abstract A novel dual-frequency Radio Frequency Identification (RFID) antenna with complementary operation mechanisms (two different operation mechanisms: near field and far field operation) is proposed. The proposed antenna is obtained by printing a rectangular-spiral-shaped and a meander-shaped line, which is placed above on a rectangular microwave substrate as a RFID tag's antenna where its ground plane is at the bottom of substrate. The proposed antenna is fed by a 50 , microstrip line printed on the same substrate, and the antenna's two resonant frequencies can be excited with good impedance matching. Closer to omni-directional radiation patterns and the lower cross-polarization levels (at least 25-dB) are also obtained. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1396,1398, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22426 [source] Dual-band circularly polarized antenna with a QUAD-EMC structureMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 3 2007The-Nan Chang Abstract In this paper, a method for obtaining a single-feed dual-band circularly polarized (CP) antenna with QUAD-EMC structure is presented. The proposed dual-band CP design was achieved by four small patches displayed on the upper surface of a first substrate, and fed electromagnetically by a large patch etched on the lower surface of the same substrate. A second FR4 and a third air substrate were added behind the first substrate to enhance the gain of the antenna. Then, by tuning the sizes of upper and lower patches and truncating patch corners respectively and properly, the proposed antenna can perform dual-band CP radiation using a single probe feed. Prototypes of the proposed antennas designed for RFID operations in the 915-MHz and 2.45-GHz bands are presented and experimentally demonstrated. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 645,647, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22231 [source] TEM characterization of M -plane InN grown on (100) LiAlO2 substrate by RF-MBEPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue S2 2009Hirokazu Nozawa Abstract In this study, we characterized the microstructure of M -plane InN using transmission electron microscopy (TEM). The M -plane InN was grown on a (100) LiAlO2 substrate using radio-frequency plasma-assisted molecular beam epitaxy (RF-MBE). We determined the epitaxial relationships of the M -plane InN and LiAlO2 using selected area electron diffraction (SAED). The epitaxial relationships were exactly the same as the M -plane GaN grown on the same substrate. Also, the M -plane InN was grown on the (100) LiAlO2 despite the high lattice mismatches between M -plane InN and LiAlO2. We observed a high density of stacking faults parallel to (0001)InN. The density was estimated about 1.8×106 cm,1, which was one order of magnitude higher than that of non-polar GaN. The correlation between threading dislocations and stacking faults is investigated. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Syntheses, Phase Behavior, Supramolecular Chirality, and Field-Effect Carrier Mobility of Asymmetrically End-Capped Mesogenic OligothiophenesCHEMISTRY - A EUROPEAN JOURNAL, Issue 14 2009Qingwei Meng Dr. Abstract Supramolecular chirality and liquid crystalline OFET: Achiral end-capped oligothiophenes can be tuned to exhibit supramolecular chirality with unique striped textures showing distinct circular dichroism signals as well as a highly ordered SmE phase that leads to high hole carrier mobility. A novel series of asymmetrically end-capped mesogenic oligothiophenes, with various oligothiophene core lengths, alkoxy tail lengths, and molecular polarities through introducing alkylsulfanyl or alkylsulfonyl functionalities as the terminal group, have been synthesized by palladium-catalyzed Suzuki cross-coupling and Kumada cross-coupling reactions as key steps. For the single end-capped oligothiophenes, CmO-Ar-OT(4)-H in which m=10, 12, 14, 16, and 18, all of these oligomers exhibited a broad temperature range of highly ordered smectic E and enantiotropic nematic phases, apart from the one with the longest octadecyloxy tail. For the double end-capped series C10O-Ar-OT(n)-R, R=Ph-SC6 or Ph-SO2C6 in which n=1, 2, 3, and 4, oligomers with more than one thiophene ring exhibited smectic A and smectic C phases, various crystal polymorphs and/or unusual low-temperature condensed phases. In the nonpolar, alkylsulfanylphenyl-substituted oligothiophene series, both the crystal/solid melting point and mesogenic clear point increased significantly with an increasing oligothiophene conjugation length. In the polar, alkylsulfonylphenyl-substituted oligothiophene series, all the oligomers showed increased melting points, but decreased mesogenic temperature intervals than those of their corresponding alkylsulfanyl counterparts. Remarkably, two different helical structures showing distinct striated textures or striped patterns were observed with a pitch of several to tens of micrometers under a polarized optical microscope upon cooling from their preceding fluidic smectic phases. The unusual twisted smectic layer structures in the thin solid films exhibiting distinct supramolecular chirality of both handednesses, revealed by circular dichroism measurements, were further confirmed by XRD analyses characterized by a sharp layer reflection together with its higher orders and diffuse wide-angle scatterings. In addition, initial studies showed that the highly ordered smectic phase of the single end-capped oligothiophenes can be utilized to improve field-effect charge mobility. C10O-Ar-OT(4)-H showed a hole mobility of 0.07,cm2,V,1,s,1 when deposited on octyltrichlorosilane-treated substrates at 140,°C and the on/off current ratios reached 5×105; on the other hand, its mobility was only 8×10,3,cm2,V,1,s,1 on the same substrate when deposited at room temperature. [source] In vitro gas production profile and the formation of end products from non- washable, insoluble washable and soluble washable fractions in some concentrate ingredientsJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 7 2007Arash Azarfar Abstract A procedure that mimics washing in the in situ incubation technique, combined with an in vitro gas and volatile fatty acids (VFAs) production technique, was used to verify the assumption that rumen degradation behaviour of material washed out of nylon bags is instantaneous and complete. In a 6 × 4 factorial arrangement of treatments with three replicates, fractions of maize, barley, milo, yellow peas, lupins (a mixture of white and spotted lupins) and round-seeded brown faba beans were subjected to an in vitro incubation technique. Fractions were whole (WHO), non-washable (NWF), insoluble washable (ISWF) and soluble washable (SWF). In a manually operated in vitro fermentation system, another 24 samples of the same substrates were fermented for VFA and ammonia analysis. Except in lupins, ISWF in the concentrate ingredients was very rich in starch. SWF was relatively rich in ash, crude protein, soluble sugars, and a residual unknown fraction but contained only a negligible quantity of starch. Thus, the fermentation characteristics of ISWF were more like WHO and NWF than SWF. Total gas production of SWF was considerably lower than the other fractions. A very rapidly degradable fraction was seen in the first phase of degradation of SWF. The pattern of fermentation end-product formation for SWF differed from that of the other fractions. Copyright © 2007 Society of Chemical Industry [source] The importance of starch and sucrose digestion in nutritive biology of synanthropic acaridid mites: ,-Amylases and ,-glucosidases are suitable targets for inhibitor-based strategies of mite control,ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY (ELECTRONIC), Issue 3 2009Tomas Erban Abstract The adaptation of nine species of mites that infest stored products for starch utilization was tested by (1) enzymatic analysis using feces and whole mite extracts, (2) biotests, and (3) inhibition experiments. Acarus siro, Aleuroglyphus ovatus, and Tyroborus lini were associated with the starch-type substrates and maltose, with higher enzymatic activities observed in whole mite extracts. Lepidoglyphus destructor was associated with the same substrates but had higher activities in feces. Dermatophagoides farinae, Chortoglyphus arcuatus, and Caloglyphus redickorzevi were associated with sucrose. Tyrophagus putrescentiae and Carpoglyphus lactis had low or intermediate enzymatic activity on the tested substrates. Biotests on starch additive diets showed accelerated growth of species associated with the starch-type substrates. The inhibitor acarbose suppressed starch hydrolysis and growth of the mites. We suggest that the species with higher starch hydrolytic activity in feces were more tolerant to acarbose, and ,-amylase and ,-glucosidase of synanthropic mites are suitable targets for inhibitor-based strategies of mite control. © 2009 Wiley Periodicals, Inc. [source] | |||||||||||||