Radiation-induced mutagenicity and lethality in tryptophan-requiring auxotrophs of escherichia coli

International Nuclear Information System (INIS)

Xu Rong; Qian Hongwei; Yao Fenying; Gu Shuzhu; Xu Jiaxin; Bi Hekan; Liu Yuying

1989-01-01

Mutation and killing caused by X-ray radiation and 60 Co γ-ray radiation were studied in three different tryptophan-requiring auxotrophs (WP2, Wp2A, Cm 891) of Escherichia coli. These testers are sensitive to base pair substitution mutagens. Cm891 carries a R-factor and is more sensitive than WP2 and WP2A to radiation-induced mutation and lethality. The results of the study show that (1) ionizing radiation was mutagenic to E. coli, (2) the order of mutagenic sensitivity among three strains to ionizing radiation was Cm891 > WP2A > WP2, (3) the dose rate of γ-ray influences mutagenicity and lethalty of E. coli strain, (4) the toxicity and mutagenicity of γ-ray were similar to X-ray when Cm891 was tested, however, γ-ray was more toxic and mutagenic than X-ray to WP2A ang WP2

Availability of Amino Acids Extends Chronological Lifespan by Suppressing Hyper-Acidification of the Environment in Saccharomyces cerevisiae.

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Yo Maruyama

Full Text Available The chronological lifespan of Saccharomyces cerevisiae represents the duration of cell survival in the postdiauxic and stationary phases. Using a prototrophic strain derived from the standard auxotrophic laboratory strain BY4742, we showed that supplementation of non-essential amino acids to a synthetic defined (SD medium increases maximal cell growth and extends the chronological lifespan. The positive effects of amino acids can be reproduced by modulating the medium pH, indicating that amino acids contribute to chronological longevity in a cell-extrinsic manner by alleviating medium acidification. In addition, we showed that the amino acid-mediated effects on extension of chronological longevity are independent of those achieved through a reduction in the TORC1 pathway, which is mediated in a cell-intrinsic manner. Since previous studies showed that extracellular acidification causes mitochondrial dysfunction and leads to cell death, our results provide a path to premature chronological aging caused by differences in available nitrogen sources. Moreover, acidification of culture medium is generally associated with culture duration and cell density; thus, further studies are required on cell physiology of auxotrophic yeast strains during the stationary phase because an insufficient supply of essential amino acids may cause alterations in environmental conditions.

Construction of tunable peptide nucleic acid junctions.

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Duan, Tanghui; He, Liu; Tokura, Yu; Liu, Xin; Wu, Yuzhou; Shi, Zhengshuang

2018-03-15

We report here the construction of 3-way and 4-way peptide nucleic acid (PNA) junctions as basic structural units for PNA nanostructuring. The incorporation of amino acid residues into PNA chains makes PNA nanostructures with more structural complexity and architectural flexibility possible, as exemplified by building 3-way PNA junctions with tunable nanopores. Given that PNA nanostructures have good thermal and enzymatic stabilities, they are expected to have broad potential applications in biosensing, drug delivery and bioengineering.

Comparative genomics of the lactic acid bacteria

Energy Technology Data Exchange (ETDEWEB)

Makarova, K.; Slesarev, A.; Wolf, Y.; Sorokin, A.; Mirkin, B.; Koonin, E.; Pavlov, A.; Pavlova, N.; Karamychev, V.; Polouchine, N.; Shakhova, V.; Grigoriev, I.; Lou, Y.; Rokhsar, D.; Lucas, S.; Huang, K.; Goodstein, D. M.; Hawkins, T.; Plengvidhya, V.; Welker, D.; Hughes, J.; Goh, Y.; Benson, A.; Baldwin, K.; Lee, J. -H.; Diaz-Muniz, I.; Dosti, B.; Smeianov, V; Wechter, W.; Barabote, R.; Lorca, G.; Altermann, E.; Barrangou, R.; Ganesan, B.; Xie, Y.; Rawsthorne, H.; Tamir, D.; Parker, C.; Breidt, F.; Broadbent, J.; Hutkins, R.; O' Sullivan, D.; Steele, J.; Unlu, G.; Saier, M.; Klaenhammer, T.; Richardson, P.; Kozyavkin, S.; Weimer, B.; Mills, D.

2006-06-01

Lactic acid-producing bacteria are associated with various plant and animal niches and play a key role in the production of fermented foods and beverages. We report nine genome sequences representing the phylogenetic and functional diversity of these bacteria. The small genomes of lactic acid bacteria encode a broad repertoire of transporters for efficient carbon and nitrogen acquisition from the nutritionally rich environments they inhabit and reflect a limited range of biosynthetic capabilities that indicate both prototrophic and auxotrophic strains. Phylogenetic analyses, comparison of gene content across the group, and reconstruction of ancestral gene sets indicate a combination of extensive gene loss and key gene acquisitions via horizontal gene transfer during the coevolution of lactic acid bacteria with their habitats.

Production of recombinant Bombyx mori nucleopolyhedrovirus in silkworm by intrahaemocoelic injection with invasive diaminopimelate auxotrophic Escherichia coli containing BmNPV-Bacmid.

Science.gov (United States)

Sun, Jingchen; Yao, Lunguang; Yao, Ning; Xu, Hua; Jin, Pengfei; Kan, Yunchao

2010-12-01

The present study elaborates a cost-effective and transfectant-free method for generating recombinant Bombyx mori (silkworm) nucleopolyhedrovirus in silkworm larvae and pupae by injecting invasive Escherichia coli carrying BmBacmid [BmNPV (B. mori nucleopolyhedrovirus)-Bacmid] into larval haemocoel. Up to 109 PFU (plaque-forming units)/ml of infective recombinant baculovirus was generated in the silkworm by intrahaemocoelic injection with 106 DAP (diaminopimelic acid) auxotrophic and BmBacmid containing E. coli cells expressing both invasin and listeriolysin. Thus 1 ml of overnight culture of E. coli is sufficient to inject more than 2000 larvae, while DAP costing up to $1 is enough to inject about 4000 larvae. Recombinant proteins can be controlled to be expressed mainly in pupae by adjusting the injection dose, too. In this new method, many original manipulations have been eliminated, including BmBacmid preparation and the subsequent complex transfection procedures. Hence it is a time- and cost-saving means for large-scale injection of B. mori for recombinant baculovirus production in comparison with the traditional transfection methods, which may play an important role in the industrial development of the BmNPV-silkworm bioreactor.

Nucleic acid constructs containing orthogonal site selective recombinases (OSSRs)

Energy Technology Data Exchange (ETDEWEB)

Gilmore, Joshua M.; Anderson, J. Christopher; Dueber, John E.

2017-08-29

The present invention provides for a recombinant nucleic acid comprising a nucleotide sequence comprising a plurality of constructs, wherein each construct independently comprises a nucleotide sequence of interest flanked by a pair of recombinase recognition sequences. Each pair of recombinase recognition sequences is recognized by a distinct recombinase. Optionally, each construct can, independently, further comprise one or more genes encoding a recombinase capable of recognizing the pair of recombinase recognition sequences of the construct. The recombinase can be an orthogonal (non-cross reacting), site-selective recombinase (OSSR).

Physical size of the donor locus and transmission of Haemophilus influenzae ampicillin resistance genes by deoxyribonucleic acid-mediated transformation

International Nuclear Information System (INIS)

Bendler, J.W. III

1976-01-01

The properties of donor deoxyribonucleic acid (DNA) from three clinical isolates and its ability to mediate the transformation of competent Rd strains to ampicillin resistance were examined. A quantitative technique for determining the resistance of individual Haemophilus influenzae cells to ampicillin was developed. When this technique was used, sensitive cells failed to tolerate levels of ampicillin greater than 0.1 to 0.2 μg/ml, whereas three resistant type b β-lactamase-producing strains could form colonies 1- to 3-μg/ml levels of the antibiotic. DNA extracted from the resistant strains elicited transformation of the auxotrophic genes in a multiply auxotrophic Rd strain. For two of the donors, transformation to ampicillin resistance occurred after the uptake of a single DNA molecule approximately 10 4 -fold less frequently than transformation of auxotrophic loci and was not observed to occur at all with the third. The frequency of transformation to ampicillin resistance was two- to fivefold higher in strain BC200 (Okinaka and Barnhart, 1974), which was cured of a defective prophage. All three clinical ampicillin-resistant strains were poor recipients, but the presence of the ampicillin resistant genes in strain BC200 did not reduce its competence

Construction of a self-cloning system in the unicellular green alga Pseudochoricystis ellipsoidea.

Science.gov (United States)

Kasai, Yuki; Oshima, Kohei; Ikeda, Fukiko; Abe, Jun; Yoshimitsu, Yuya; Harayama, Shigeaki

2015-01-01

Microalgae have received considerable interest as a source of biofuel production. The unicellular green alga Pseudochoricystis ellipsoidea (non-validated scientific name) strain Obi appears to be suitable for large-scale cultivation in outdoor open ponds for biodiesel production because it accumulates lipids to more than 30 % of dry cell weight under nitrogen-depleted conditions. It also grows rapidly under acidic conditions at which most protozoan grazers of microalgae may not be tolerant. The lipid productivity of this alga could be improved using genetic engineering techniques; however, genetically modified organisms are the subject of regulation by specific laws. Therefore, the aim of this study was to develop a self-cloning-based positive selection system for the breeding of P. ellipsoidea. In this study, uracil auxotrophic mutants were isolated after the mutagenesis of P. ellipsoidea using either ultraviolet light or a transcription activator-like effector nuclease (TALEN) system. The cDNA of the uridine monophosphate synthase gene (PeUMPS) of P. ellipsoidea was cloned downstream of the promoter of either a beta-tubulin gene (PeTUBULIN1) or the gene for the small subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (PeRBCS) to construct the pUT1 or pUT2 plasmid, respectively. These constructs were introduced into uracil auxotroph strains, and genetically complementary transformants were isolated successfully on minimal agar plates. Use of Noble agar as the solidifying agent was essential to avoid the development of false-positive colonies. It took more than 6 weeks for the formation of colonies of pUT1 transformants, whereas pUT2 transformants formed colonies in 2 weeks. Real-time PCR revealed that there were more PeUMPS transcripts in pUT2 transformants than in pUT1 transformants. Uracil synthesis (Ura(+)) transformants were also obtained using a gene cassette consisting solely of PeUMPS flanked by the PeRBCS promoter and terminator. A self

Inhibitors of amino acids biosynthesis as antifungal agents.

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Jastrzębowska, Kamila; Gabriel, Iwona

2015-02-01

Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

Construction and Analysis of Two Genome-Scale Deletion Libraries for Bacillus subtilis.

Science.gov (United States)

Koo, Byoung-Mo; Kritikos, George; Farelli, Jeremiah D; Todor, Horia; Tong, Kenneth; Kimsey, Harvey; Wapinski, Ilan; Galardini, Marco; Cabal, Angelo; Peters, Jason M; Hachmann, Anna-Barbara; Rudner, David Z; Allen, Karen N; Typas, Athanasios; Gross, Carol A

2017-03-22

A systems-level understanding of Gram-positive bacteria is important from both an environmental and health perspective and is most easily obtained when high-quality, validated genomic resources are available. To this end, we constructed two ordered, barcoded, erythromycin-resistance- and kanamycin-resistance-marked single-gene deletion libraries of the Gram-positive model organism, Bacillus subtilis. The libraries comprise 3,968 and 3,970 genes, respectively, and overlap in all but four genes. Using these libraries, we update the set of essential genes known for this organism, provide a comprehensive compendium of B. subtilis auxotrophic genes, and identify genes required for utilizing specific carbon and nitrogen sources, as well as those required for growth at low temperature. We report the identification of enzymes catalyzing several missing steps in amino acid biosynthesis. Finally, we describe a suite of high-throughput phenotyping methodologies and apply them to provide a genome-wide analysis of competence and sporulation. Altogether, we provide versatile resources for studying gene function and pathway and network architecture in Gram-positive bacteria. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Exometabolomics Assisted Design and Validation of Synthetic Obligate Mutualism.

Science.gov (United States)

Kosina, Suzanne M; Danielewicz, Megan A; Mohammed, Mujahid; Ray, Jayashree; Suh, Yumi; Yilmaz, Suzan; Singh, Anup K; Arkin, Adam P; Deutschbauer, Adam M; Northen, Trent R

2016-07-15

Synthetic microbial ecology has the potential to enhance the productivity and resiliency of biotechnology processes compared to approaches using single isolates. Engineering microbial consortia is challenging; however, one approach that has attracted significant attention is the creation of synthetic obligate mutualism using auxotrophic mutants that depend on each other for exchange or cross-feeding of metabolites. Here, we describe the integration of mutant library fitness profiling with mass spectrometry based exometabolomics as a method for constructing synthetic mutualism based on cross-feeding. Two industrially important species lacking known ecological interactions, Zymomonas mobilis and Escherichia coli, were selected as the test species. Amino acid exometabolites identified in the spent medium of Z. mobilis were used to select three corresponding E. coli auxotrophs (proA, pheA and IlvA), as potential E. coli counterparts for the coculture. A pooled mutant fitness assay with a Z. mobilis transposon mutant library was used to identify mutants with improved growth in the presence of E. coli. An auxotroph mutant in a gene (ZMO0748) with sequence similarity to cysteine synthase A (cysK), was selected as the Z. mobilis counterpart for the coculture. Exometabolomic analysis of spent E. coli medium identified glutathione related metabolites as potentially available for rescue of the Z. mobilis cysteine synthase mutant. Three sets of cocultures between the Z. mobilis auxotroph and each of the three E. coli auxotrophs were monitored by optical density for growth and analyzed by flow cytometry to confirm high cell counts for each species. Taken together, our methods provide a technological framework for creating synthetic mutualisms combining existing screening based methods and exometabolomics for both the selection of obligate mutualism partners and elucidation of metabolites involved in auxotroph rescue.

Bioaccumulation of metals in constructed wetlands used to treat acid drainage

International Nuclear Information System (INIS)

Edwards, G.S.; Mays, P.A.

1994-01-01

Constructed wetlands are being used extensively as a potential mitigation for acid drainage. However, removal of metals to meet compliance requirements has varied among wetlands, ranging from partial to total success. In addition, wetlands are sinks for contaminants found in acid drainage, and bioaccumulation of these contaminants to levels that would adversely affect the food web is of growing concern. The primary objective of this project was to determine whether bioaccumulation of metals occurs in wetlands constructed for treatment of acid drainage. Water, sediment, plant and benthos samples were collected from two wetlands constructed by the Tennessee Valley Authority and a natural wetland in the spring and fall of 1992, and metal concentrations were determined. One of the constructed wetlands, Impoundment 1, has generally been in compliance for NPDES; the other, Widow's Creek, has never been in compliance. Preliminary results indicate similarities in sediment and plant metal concentrations between Impoundment 1 and the natural wetland and greater metal concentrations in the sediment and plants at Widow's Creek. Data also indicate that Mn, Zn, Cu, Ni, and Cr are being accumulated in the plants at each wetland. However, accumulation of metals by these plants probably accounts for only a small percentage of the removal of the annual metal load supplied to each wetland. Bioaccumulation of metals in the benthic organisms at each wetland is currently being investigated

The construction of an amino acid network for understanding protein structure and function.

Science.gov (United States)

Yan, Wenying; Zhou, Jianhong; Sun, Maomin; Chen, Jiajia; Hu, Guang; Shen, Bairong

2014-06-01

Amino acid networks (AANs) are undirected networks consisting of amino acid residues and their interactions in three-dimensional protein structures. The analysis of AANs provides novel insight into protein science, and several common amino acid network properties have revealed diverse classes of proteins. In this review, we first summarize methods for the construction and characterization of AANs. We then compare software tools for the construction and analysis of AANs. Finally, we review the application of AANs for understanding protein structure and function, including the identification of functional residues, the prediction of protein folding, analyzing protein stability and protein-protein interactions, and for understanding communication within and between proteins.

An amino acid depleted cell-free protein synthesis system for the incorporation of non-canonical amino acid analogs into proteins.

Science.gov (United States)

Singh-Blom, Amrita; Hughes, Randall A; Ellington, Andrew D

2014-05-20

Residue-specific incorporation of non-canonical amino acids into proteins is usually performed in vivo using amino acid auxotrophic strains and replacing the natural amino acid with an unnatural amino acid analog. Herein, we present an efficient amino acid depleted cell-free protein synthesis system that can be used to study residue-specific replacement of a natural amino acid by an unnatural amino acid analog. This system combines a simple methodology and high protein expression titers with a high-efficiency analog substitution into a target protein. To demonstrate the productivity and efficacy of a cell-free synthesis system for residue-specific incorporation of unnatural amino acids in vitro, we use this system to show that 5-fluorotryptophan and 6-fluorotryptophan substituted streptavidin retain the ability to bind biotin despite protein-wide replacement of a natural amino acid for the amino acid analog. We envisage this amino acid depleted cell-free synthesis system being an economical and convenient format for the high-throughput screening of a myriad of amino acid analogs with a variety of protein targets for the study and functional characterization of proteins substituted with unnatural amino acids when compared to the currently employed in vivo methodologies. Copyright © 2014 Elsevier B.V. All rights reserved.

Auxotrophy-stimulated sensitivity to quaternary ammonium salts and its relation to active transport in yeast

International Nuclear Information System (INIS)

Lachowicz, T.M.; Oblak, E.; Piatkowski, J.

1992-01-01

In previous studies we have observed that auxotrophic mutants of yeast were much more sensitive to quaternary ammonium salts than the corresponding isogenic wild type strains. The super sensitivity of the auxotrophs seems to be a characteristic feature of yeast and yeast-like microorganisms: the level of sensitivity of the quaternary ammonium salts of the bacterial auxotrophs and their original prototrophic forms appeared to be the same. The super sensitivity of yeast auxotrophs disappeared on minimal media with ammonium as a nitrogen source. In this report there are presented the data indicating that enrichment of the minimal medium with arginine restores the super sensitivity of auxotrophic yeast mutants to the quaternary ammonium salts. The results of amino-acid transport into the auxotrophic yeast cells treated with a quaternary ammonium salt in the presence and absence of arginine are given. A working hypothesis of the mechanism of these salts action as a specific inhibition of nutrient transport is discussed. (author). 19 refs, 3 figs, 8 figs

Secretion of Rhoptry and Dense Granule Effector Proteins by Nonreplicating Toxoplasma gondii Uracil Auxotrophs Controls the Development of Antitumor Immunity.

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Barbara A Fox

2016-07-01

Full Text Available Nonreplicating type I uracil auxotrophic mutants of Toxoplasma gondii possess a potent ability to activate therapeutic immunity to established solid tumors by reversing immune suppression in the tumor microenvironment. Here we engineered targeted deletions of parasite secreted effector proteins using a genetically tractable Δku80 vaccine strain to show that the secretion of specific rhoptry (ROP and dense granule (GRA proteins by uracil auxotrophic mutants of T. gondii in conjunction with host cell invasion activates antitumor immunity through host responses involving CD8α+ dendritic cells, the IL-12/interferon-gamma (IFN-γ TH1 axis, as well as CD4+ and CD8+ T cells. Deletion of parasitophorous vacuole membrane (PVM associated proteins ROP5, ROP17, ROP18, ROP35 or ROP38, intravacuolar network associated dense granule proteins GRA2 or GRA12, and GRA24 which traffics past the PVM to the host cell nucleus severely abrogated the antitumor response. In contrast, deletion of other secreted effector molecules such as GRA15, GRA16, or ROP16 that manipulate host cell signaling and transcriptional pathways, or deletion of PVM associated ROP21 or GRA3 molecules did not affect the antitumor activity. Association of ROP18 with the PVM was found to be essential for the development of the antitumor responses. Surprisingly, the ROP18 kinase activity required for resistance to IFN-γ activated host innate immunity related GTPases and virulence was not essential for the antitumor response. These data show that PVM functions of parasite secreted effector molecules, including ROP18, manipulate host cell responses through ROP18 kinase virulence independent mechanisms to activate potent antitumor responses. Our results demonstrate that PVM associated rhoptry effector proteins secreted prior to host cell invasion and dense granule effector proteins localized to the intravacuolar network and host nucleus that are secreted after host cell invasion coordinately

Pimelic acid, the first precursor of the Bacillus subtilis biotin synthesis pathway, exists as the free acid and is assembled by fatty acid synthesis.

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Manandhar, Miglena; Cronan, John E

2017-05-01

Biotin synthetic pathways are readily separated into two stages, synthesis of the seven carbon α, ω-dicarboxylic acid pimelate moiety and assembly of the fused heterocyclic rings. The biotin pathway genes responsible for pimelate moiety synthesis vary widely among bacteria whereas the ring synthesis genes are highly conserved. Bacillus subtilis seems to have redundant genes, bioI and bioW, for generation of the pimelate intermediate. Largely consistent with previous genetic studies it was found that deletion of bioW caused a biotin auxotrophic phenotype whereas deletion of bioI did not. BioW is a pimeloyl-CoA synthetase that converts pimelic acid to pimeloyl-CoA. The essentiality of BioW for biotin synthesis indicates that the free form of pimelic acid is an intermediate in biotin synthesis although this is not the case in E. coli. Since the origin of pimelic acid in Bacillus subtilis is unknown, 13 C-NMR studies were carried out to decipher the pathway for its generation. The data provided evidence for the role of free pimelate in biotin synthesis and the involvement of fatty acid synthesis in pimelate production. Cerulenin, an inhibitor of the key fatty acid elongation enzyme, FabF, markedly decreased biotin production by B. subtilis resting cells whereas a strain having a cerulenin-resistant FabF mutant produced more biotin. In addition, supplementation with pimelic acid fully restored biotin production in cerulenin-treated cells. These results indicate that pimelic acid originating from fatty acid synthesis pathway is a bona fide precursor of biotin in B. subtilis. © 2017 John Wiley & Sons Ltd.

Optical nano-biosensing interface via nucleic acid amplification strategy: construction and application.

Science.gov (United States)

Zhou, Hong; Liu, Jing; Xu, Jing-Juan; Zhang, Shu-Sheng; Chen, Hong-Yuan

2018-03-21

Modern optical detection technology plays a critical role in current clinical detection due to its high sensitivity and accuracy. However, higher requirements such as extremely high detection sensitivity have been put forward due to the clinical needs for the early finding and diagnosing of malignant tumors which are significant for tumor therapy. The technology of isothermal amplification with nucleic acids opens up avenues for meeting this requirement. Recent reports have shown that a nucleic acid amplification-assisted modern optical sensing interface has achieved satisfactory sensitivity and accuracy, high speed and specificity. Compared with isothermal amplification technology designed to work completely in a solution system, solid biosensing interfaces demonstrated better performances in stability and sensitivity due to their ease of separation from the reaction mixture and the better signal transduction on these optical nano-biosensing interfaces. Also the flexibility and designability during the construction of these nano-biosensing interfaces provided a promising research topic for the ultrasensitive detection of cancer diseases. In this review, we describe the construction of the burgeoning number of optical nano-biosensing interfaces assisted by a nucleic acid amplification strategy, and provide insightful views on: (1) approaches to the smart fabrication of an optical nano-biosensing interface, (2) biosensing mechanisms via the nucleic acid amplification method, (3) the newest strategies and future perspectives.

Stable Isotope Labeling by Amino Acids in Cell Culture (SILAC) Applied to Quantitative Proteomics of Bacillus subtilis

DEFF Research Database (Denmark)

Soufi, Boumediene; Kumar, C.; Gnad, F.

2010-01-01

We applied stable isotope labeling by amino acids in cell culture (SILAC) to large-scale quantitative proteomics analyses of the model bacterium Bacillus subtilis in two physiological conditions: growth on succinate and growth under phosphate starvation. Using a B. subtilis strain auxotrophic...... of the most comprehensive quantitative proteomics studies in bacteria, covering more than 75% of the B. subtilis genes expressed in the log phase of growth. Furthermore, we detect and quantify dynamics of 35 Ser/Thr/Tyr phosphorylation sites under growth on succinate, and 10 phosphorylation sites under...

Supramolecular Coordination Assemblies Constructed From Multifunctional Azole-Containing Carboxylic Acids

Directory of Open Access Journals (Sweden)

Yuheng Deng

2010-05-01

Full Text Available This paper provides a brief review of recent progress in the field of metal coordination polymers assembled from azole-containing carboxylic acids and gives a diagrammatic summary of the diversity of topological structures in the resulting infinite metal-organic coordination networks (MOCNs. Azole-containing carboxylic acids are a favorable kind of multifunctional ligand to construct various metal complexes with isolated complexes and one, two and three dimensional structures, whose isolated complexes are not the focus of this review. An insight into the topology patterns of the infinite coordination polymers is provided. Analyzed topologies are compared with documented topologies and catalogued by the nature of nodes and connectivity pattern. New topologies which are not available from current topology databases are described and demonstrated graphically.

The use of constructed wetlands in the treatment of acid mine drainage

International Nuclear Information System (INIS)

Perry, A.; Kleinmann, R.L.P.

1991-01-01

US government regulations require that all effluents from industrial operations, including mining, meet certain water quality standards. Constructed wetlands have proven to be useful in helping to attain those standards. Application of this biotechnology to mine water drainage can reduce water treatment costs and improve water quality in streams and rivers adversely affected by acidic mine water drainage from abandoned mines. Over 400 constructed wetland water treatment systems have been built on mined lands largely as a result of research by the US Bureau of Mines. Wetlands are passive biological treatment systems that are relatively inexpensive to construct and require minimal maintenance. Chemical treatment costs are reduced sufficiently to repay the cost of construction in less than a year. The mine waste water is typically treated in a series of excavated ponds that resemble small marsh areas. The ponds are engineered to facilitate bacterial oxidation of iron. Ideally, the water then flows through a composted organic substrate supporting a population of sulphate-reducing bacteria which raises the pH. Constructed wetlands in the USA are described - their history, functions, construction methodologies, applicabilities, limitations and costs. (author). 26 refs, 2 figs

The use of constructed wetlands in the treatment of acid mine drainage

Energy Technology Data Exchange (ETDEWEB)

Perry, A [Department of the Interior, Washington, DC (United States). Bureau of Mines; Kleinmann, R L.P. [Department of the Interior, Pittsburgh, PA (United States). Bureau of Mines

1991-08-01

US government regulations require that all effluents from industrial operations, including mining, meet certain water quality standards. Constructed wetlands have proven to be useful in helping to attain those standards. Application of this biotechnology to mine water drainage can reduce water treatment costs and improve water quality in streams and rivers adversely affected by acidic mine water drainage from abandoned mines. Over 400 constructed wetland water treatment systems have been built on mined lands largely as a result of research by the US Bureau of Mines. Wetlands are passive biological treatment systems that are relatively inexpensive to construct and require minimal maintenance. Chemical treatment costs are reduced sufficiently to repay the cost of construction in less than a year. The mine waste water is typically treated in a series of excavated ponds that resemble small marsh areas. The ponds are engineered to facilitate bacterial oxidation of iron. Ideally, the water then flows through a composted organic substrate supporting a population of sulphate-reducing bacteria which raises the pH. Constructed wetlands in the USA are described - their history, functions, construction methodologies, applicabilities, limitations and costs. (author). 26 refs, 2 figs.

Engineering Escherichia coli Nicotinic Acid Mononucleotide Adenylyltransferase for Fully Active Amidated NAD Biosynthesis.

Science.gov (United States)

Wang, Xueying; Zhou, Yongjin J; Wang, Lei; Liu, Wujun; Liu, Yuxue; Peng, Chang; Zhao, Zongbao K

2017-07-01

NAD and its reduced form NADH function as essential redox cofactors and have major roles in determining cellular metabolic features. NAD can be synthesized through the deamidated and amidated pathways, for which the key reaction involves adenylylation of nicotinic acid mononucleotide (NaMN) and nicotinamide mononucleotide (NMN), respectively. In Escherichia coli , NAD de novo biosynthesis depends on the protein NadD-catalyzed adenylylation of NaMN to nicotinic acid adenine dinucleotide (NaAD), followed by NAD synthase-catalyzed amidation. In this study, we engineered NadD to favor NMN for improved amidated pathway activity. We designed NadD mutant libraries, screened by a malic enzyme-coupled colorimetric assay, and identified two variants, 11B4 (Y84V/Y118D) and 16D8 (A86W/Y118N), with a high preference for NMN. Whereas in the presence of NMN both variants were capable of enabling the viability of cells of E. coli BW25113-derived NAD-auxotrophic strain YJE003, for which the last step of the deamidated pathway is blocked, the 16D8 expression strain could grow without exogenous NMN and accumulated a higher cellular NAD(H) level than BW25113 in the stationary phase. These mutants established fully active amidated NAD biosynthesis and offered a new opportunity to manipulate NAD metabolism for biocatalysis and metabolic engineering. IMPORTANCE Adenylylation of nicotinic acid mononucleotide (NaMN) and adenylylation of nicotinamide mononucleotide (NMN), respectively, are the key steps in the deamidated and amidated pathways for NAD biosynthesis. In most organisms, canonical NAD biosynthesis follows the deamidated pathway. Here we engineered Escherichia coli NaMN adenylyltransferase to favor NMN and expressed the mutant enzyme in an NAD-auxotrophic E. coli strain that has the last step of the deamidated pathway blocked. The engineered strain survived in M9 medium, which indicated the implementation of a functional amidated pathway for NAD biosynthesis. These results enrich

Preservation of genes involved in sterol metabolism in cholesterol auxotrophs: facts and hypotheses.

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Giovanna Vinci

Full Text Available BACKGROUND: It is known that primary sequences of enzymes involved in sterol biosynthesis are well conserved in organisms that produce sterols de novo. However, we provide evidence for a preservation of the corresponding genes in two animals unable to synthesize cholesterol (auxotrophs: Drosophila melanogaster and Caenorhabditis elegans. PRINCIPAL FINDINGS: We have been able to detect bona fide orthologs of several ERG genes in both organisms using a series of complementary approaches. We have detected strong sequence divergence between the orthologs of the nematode and of the fruitfly; they are also very divergent with respect to the orthologs in organisms able to synthesize sterols de novo (prototrophs. Interestingly, the orthologs in both the nematode and the fruitfly are still under selective pressure. It is possible that these genes, which are not involved in cholesterol synthesis anymore, have been recruited to perform different new functions. We propose a more parsimonious way to explain their accelerated evolution and subsequent stabilization. The products of ERG genes in prototrophs might be involved in several biological roles, in addition to sterol synthesis. In the case of the nematode and the fruitfly, the relevant genes would have lost their ancestral function in cholesterogenesis but would have retained the other function(s, which keep them under pressure. CONCLUSIONS: By exploiting microarray data we have noticed a strong expressional correlation between the orthologs of ERG24 and ERG25 in D. melanogaster and genes encoding factors involved in intracellular protein trafficking and folding and with Start1 involved in ecdysteroid synthesis. These potential functional connections are worth being explored not only in Drosophila, but also in Caenorhabditis as well as in sterol prototrophs.

Design, synthesis and docking studies of novel dipeptidyl boronic acid proteasome inhibitors constructed from αα- and αβ-amino acids.

Science.gov (United States)

Shi, Jingmiao; Lei, Meng; Wu, Wenkui; Feng, Huayun; Wang, Jia; Chen, Shanshan; Zhu, Yongqiang; Hu, Shihe; Liu, Zhaogang; Jiang, Cheng

2016-04-15

A series of novel dipeptidyl boronic acid proteasome inhibitors constructed from αα- and αβ-amino acids were designed and synthesized. Their structures were elucidated by (1)H NMR, (13)C NMR, LC-MS and HRMS. These compounds were evaluated for their β5 subunit inhibitory activities of human proteasome. The results showed that dipeptidyl boronic acid inhibitors composed of αα-amino acids were as active as bortezomib. Interestingly, the activities of those derived from αβ-amino acids lost completely. Of all the inhibitors, compound 22 (IC50=4.82 nM) was the most potent for the inhibition of proteasome activity. Compound 22 was also the most active against three MM cell lines with IC50 values less than 5 nM in inhibiting cell growth assays. Molecular docking studies displayed that 22 fitted very well in the β5 subunit active pocket of proteasome. Copyright © 2016. Published by Elsevier Ltd.

Phosphatidylserine biosynthesis in cultured Chinese hamster ovary cells. II. Isolation and characterization of phosphatidylserine auxotrophs

International Nuclear Information System (INIS)

Kuge, O.; Nishijima, M.; Akamatsu, Y.

1986-01-01

Chinese hamster ovary (CHO) cell mutants that required exogenously added phosphatidylserine for cell growth were isolated by using the replica technique with polyester cloth, and three such mutants were characterized. Labeling experiments on intact cells with 32 Pi and L-[U- 14 C]serine revealed that a phosphatidylserine auxotroph, designated as PSA-3, was strikingly defective in phosphatidylserine biosynthesis. When cells were grown for 2 days without phosphatidylserine, the phosphatidylserine content of PSA-3 was about one-third of that of the parent. In extracts of the mutant, the enzymatic activity of the base-exchange reaction of phospholipids with serine producing phosphatidylserine was reduced to 33% of that in the parent; in addition, the activities of base-exchange reactions of phospholipids with choline and ethanolamine in the mutant were also reduced to 1 and 45% of those in the parent, respectively. Furthermore, it was demonstrated that the serine-exchange activity in the parent was inhibited approximately 60% when choline was added to the reaction mixture whereas that in the mutant was not significantly affected. From the results presented here, we conclude the following. There are at least two kinds of serine-exchange enzymes in CHO cells; one (serine-exchange enzyme I) can catalyze the base-exchange reactions of phospholipids with serine, choline, and ethanolamine while the other (serine-exchange enzyme II) does not use the choline as a substrate. Serine-exchange enzyme I, in which mutant PSA-3 is defective, plays a major role in phosphatidylserine biosynthesis in CHO cells. Serine-exchange enzyme I is essential for the growth of CHO cells

Performance of the auxotrophic Saccharomyces cerevisiae BY4741 as host for the production of IL-1β in aerated fed-batch reactor: role of ACA supplementation, strain viability, and maintenance energy

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Zueco Jesus

2009-12-01

Full Text Available Abstract Background Saccharomyces cerevisiae BY4741 is an auxotrophic commonly used strain. In this work it has been used as host for the expression and secretion of human interleukin-1β (IL1β, using the cell wall protein Pir4 as fusion partner. To achieve high cell density and, consequently, high product yield, BY4741 [PIR4-IL1β] was cultured in an aerated fed-batch reactor, using a defined mineral medium supplemented with casamino acids as ACA (auxotrophy-complementing amino acid source. Also the S. cerevisiae mutant BY4741 Δyca1 [PIR4-IL1β], carrying the deletion of the YCA1 gene coding for a caspase-like protein involved in the apoptotic response, was cultured in aerated fed-batch reactor and compared to the parental strain, to test the effect of this mutation on strain robustness. Viability of the producer strains was examined during the runs and a mathematical model, which took into consideration the viable biomass present in the reactor and the glucose consumption for both growth and maintenance, was developed to describe and explain the time-course evolution of the process for both, the BY4741 parental and the BY4741 Δyca1 mutant strain. Results Our results show that the concentrations of ACA in the feeding solution, corresponding to those routinely used in the literature, are limiting for the growth of S. cerevisiae BY4741 [PIR4-IL1β] in fed-batch reactor. Even in the presence of a proper ACA supplementation, S. cerevisiae BY4741 [PIR4-IL1β] did not achieve a high cell density. The Δyca1 deletion did not have a beneficial effect on the overall performance of the strain, but it had a clear effect on its viability, which was not impaired during fed-batch operations, as shown by the kd value (0.0045 h-1, negligible if compared to that of the parental strain (0.028 h-1. However, independently of their robustness, both the parental and the Δyca1 mutant ceased to grow early during fed-batch runs, both strains using most of the

Plasmid construction using recombination activity in the fission yeast Schizosaccharomyces pombe.

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Ayako Chino

Full Text Available BACKGROUND: Construction of plasmids is crucial in modern genetic manipulation. As of now, the common method for constructing plasmids is to digest specific DNA sequences with restriction enzymes and to ligate the resulting DNA fragments with DNA ligase. Another potent method to construct plasmids, known as gap-repair cloning (GRC, is commonly used in the budding yeast Saccharomyces cerevisiae. GRC makes use of the homologous recombination activity that occurs within the yeast cells. Due to its flexible design and efficiency, GRC has been frequently used for constructing plasmids with complex structures as well as genome-wide plasmid collections. Although there have been reports indicating GRC feasibility in the fission yeast Schizosaccharomyces pombe, this species is not commonly used for GRC as systematic studies of reporting GRC efficiency in S. pombe have not been performed till date. METHODOLOGY/PRINCIPAL FINDINGS: We investigated GRC efficiency in S. pombe in this study. We first showed that GRC was feasible in S. pombe by constructing a plasmid that contained the LEU2 auxotrophic marker gene in vivo and showed sufficient efficiency with short homology sequences (>25 bp. No preference was shown for the sequence length from the cut site in the vector plasmid. We next showed that plasmids could be constructed in a proper way using 3 DNA fragments with 70% efficiency without any specific selections being made. The GRC efficiency with 3 DNA fragments was dramatically increased >95% in lig4Delta mutant cell, where non-homologous end joining is deficient. Following this approach, we successfully constructed plasmid vectors with leu1+, ade6+, his5+, and lys1+ markers with the low-copy stable plasmid pDblet as a backbone by applying GRC in S. pombe. CONCLUSIONS/SIGNIFICANCE: We concluded that GRC was sufficiently feasible in S. pombe for genome-wide gene functional analysis as well as for regular plasmid construction. Plasmids with different

Biological Functions of ilvC in Branched-Chain Fatty Acid Synthesis and Diffusible Signal Factor Family Production in Xanthomonas campestris

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Kai-Huai Li

2017-12-01

Full Text Available In bacteria, the metabolism of branched-chain amino acids (BCAAs is tightly associated with branched-chain fatty acids (BCFAs synthetic pathways. Although previous studies have reported on BCFAs biosynthesis, more detailed associations between BCAAs metabolism and BCFAs biosynthesis remain to be addressed. In this study, we deleted the ilvC gene, which encodes ketol-acid reductoisomerase in the BCAAs synthetic pathway, from the Xanthomonas campestris pv. campestris (Xcc genome. We characterized gene functions in BCFAs biosynthesis and production of the diffusible signal factor (DSF family signals. Disruption of ilvC caused Xcc to become auxotrophic for valine and isoleucine, and lose the ability to synthesize BCFAs via carbohydrate metabolism. Furthermore, ilvC mutant reduced the ability to produce DSF-family signals, especially branched-chain DSF-family signals, which might be the main reason for Xcc reduction of pathogenesis toward host plants. In this report, we confirmed that BCFAs do not have major functions in acclimatizing Xcc cells to low temperatures.

Codes in the codons: construction of a codon/amino acid periodic table and a study of the nature of specific nucleic acid-protein interactions.

Science.gov (United States)

Benyo, B; Biro, J C; Benyo, Z

2004-01-01

The theory of "codon-amino acid coevolution" was first proposed by Woese in 1967. It suggests that there is a stereochemical matching - that is, affinity - between amino acids and certain of the base triplet sequences that code for those amino acids. We have constructed a common periodic table of codons and amino acids, where the nucleic acid table showed perfect axial symmetry for codons and the corresponding amino acid table also displayed periodicity regarding the biochemical properties (charge and hydrophobicity) of the 20 amino acids and the position of the stop signals. The table indicates that the middle (2/sup nd/) amino acid in the codon has a prominent role in determining some of the structural features of the amino acids. The possibility that physical contact between codons and amino acids might exist was tested on restriction enzymes. Many recognition site-like sequences were found in the coding sequences of these enzymes and as many as 73 examples of codon-amino acid co-location were observed in the 7 known 3D structures (December 2003) of endonuclease-nucleic acid complexes. These results indicate that the smallest possible units of specific nucleic acid-protein interaction are indeed the stereochemically compatible codons and amino acids.

Heterologous Expression of the Carrot Hsp17.7 gene Increased Growth, Cell Viability, and Protein Solubility in Transformed Yeast (Saccharomyces cerevisiae) under Heat, Cold, Acid, and Osmotic Stress Conditions.

Science.gov (United States)

Ko, Eunhye; Kim, Minhye; Park, Yunho; Ahn, Yeh-Jin

2017-08-01

In industrial fermentation of yeast (Saccharomyces cerevisiae), culture conditions are often modified from the optimal growth conditions of the cells to maintain large-scale cultures and/or to increase recombinant protein production. However, altered growth conditions can be stressful to yeast cells resulting in reduced cell growth and viability. In this study, a small heat shock protein gene from carrot (Daucus carota L.), Hsp17.7, was inserted into the yeast genome via homologous recombination to increase tolerance to stress conditions that can occur during industrial culture. A DNA construct, Translational elongation factor gene promoter-carrot Hsp17.7 gene-Phosphoribosyl-anthranilate isomerase gene (an auxotrophic marker), was generated by a series of PCRs and introduced into the chromosome IV of the yeast genome. Immunoblot analysis showed that carrot Hsp17.7 accumulated in the transformed yeast cell lines. Growth rates and cell viability of these cell lines were higher than control cell lines under heat, cold, acid, and hyperosmotic stress conditions. Soluble protein levels were higher in the transgenic cell lines than control cell lines under heat and cold conditions, suggesting the molecular chaperone function of the recombinant Hsp17.7. This study showed that a recombinant DNA construct containing a HSP gene from carrot was successfully expressed in yeast by homologous recombination and increased tolerances to abiotic stress conditions.

Plasmodium falciparum responds to amino acid starvation by entering into a hibernatory state.

Science.gov (United States)

Babbitt, Shalon E; Altenhofen, Lindsey; Cobbold, Simon A; Istvan, Eva S; Fennell, Clare; Doerig, Christian; Llinás, Manuel; Goldberg, Daniel E

2012-11-20

The human malaria parasite Plasmodium falciparum is auxotrophic for most amino acids. Its amino acid needs are met largely through the degradation of host erythrocyte hemoglobin; however the parasite must acquire isoleucine exogenously, because this amino acid is not present in adult human hemoglobin. We report that when isoleucine is withdrawn from the culture medium of intraerythrocytic P. falciparum, the parasite slows its metabolism and progresses through its developmental cycle at a reduced rate. Isoleucine-starved parasites remain viable for 72 h and resume rapid growth upon resupplementation. Protein degradation during starvation is important for maintenance of this hibernatory state. Microarray analysis of starved parasites revealed a 60% decrease in the rate of progression through the normal transcriptional program but no other apparent stress response. Plasmodium parasites do not possess a TOR nutrient-sensing pathway and have only a rudimentary amino acid starvation-sensing eukaryotic initiation factor 2α (eIF2α) stress response. Isoleucine deprivation results in GCN2-mediated phosphorylation of eIF2α, but kinase-knockout clones still are able to hibernate and recover, indicating that this pathway does not directly promote survival during isoleucine starvation. We conclude that P. falciparum, in the absence of canonical eukaryotic nutrient stress-response pathways, can cope with an inconsistent bloodstream amino acid supply by hibernating and waiting for more nutrient to be provided.

Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

DEFF Research Database (Denmark)

Kouril, M.; Christensen, Erik; Eriksen, S.

2011-01-01

The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 8C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE...

Biocomputional construction of a gene network under acid stress in Synechocystis sp. PCC 6803.

Science.gov (United States)

Li, Yi; Rao, Nini; Yang, Feng; Zhang, Ying; Yang, Yang; Liu, Han-ming; Guo, Fengbiao; Huang, Jian

2014-01-01

Acid stress is one of the most serious threats that cyanobacteria have to face, and it has an impact at all levels from genome to phenotype. However, very little is known about the detailed response mechanism to acid stress in this species. We present here a general analysis of the gene regulatory network of Synechocystis sp. PCC 6803 in response to acid stress using comparative genome analysis and biocomputational prediction. In this study, we collected 85 genes and used them as an initial template to predict new genes through co-regulation, protein-protein interactions and the phylogenetic profile, and 179 new genes were obtained to form a complete template. In addition, we found that 11 enriched pathways such as glycolysis are closely related to the acid stress response. Finally, we constructed a regulatory network for the intricate relationship of these genes and summarize the key steps in response to acid stress. This is the first time a bioinformatic approach has been taken systematically to gene interactions in cyanobacteria and the elaboration of their cell metabolism and regulatory pathways under acid stress, which is more efficient than a traditional experimental study. The results also provide theoretical support for similar research into environmental stresses in cyanobacteria and possible industrial applications. Copyright © 2014 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Genetic complexity of fusidic acid-resistant small colony variants (SCV in Staphylococcus aureus.

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Jonas Lannergård

Full Text Available FusE mutants are fusidic acid-resistant small colony variants (SCVs of Staphylococcus aureus that can be selected with aminoglycosides. All FusE SCVs have mutations in rplF, encoding ribosomal protein L6. However, individual FusE mutants including some with the same mutation in rplF display auxotrophy for either hemin or menadione, suggesting that additional mutations are involved. Here we show that FusE SCVs can be divided into three genetic sub-groups and that some carry an additional mutation, in one of the genes required for hemin biosynthesis, or in one of the genes required for menadione biosynthesis. Reversion analysis and genome sequencing support the hypothesis that these combinations of mutations in the rplF, hem, and/or men genes can account for the SCV and auxotrophic phenotypes of FusE mutants.

The distribution of common construction materials at risk to acid deposition in the United States

Science.gov (United States)

Lipfert, Frederick W.; Daum, Mary L.

Information on the geographic distribution of various types of exposed materials is required to estimate the economic costs of damage to construction materials from acid deposition. This paper focuses on the identification, evaluation and interpretation of data describing the distributions of exterior construction materials, primarily in the United States. This information could provide guidance on how data needed for future economic assessments might be acquired in the most cost-effective ways. Materials distribution surveys from 16 cities in the U.S. and Canada and five related databases from government agencies and trade organizations were examined. Data on residential buildings are more commonly available than on nonresidential buildings; little geographically resolved information on distributions of materials in infrastructure was found. Survey results generally agree with the appropriate ancillary databases, but the usefulness of the databases is often limited by their coarse spatial resolution. Information on those materials which are most sensitive to acid deposition is especially scarce. Since a comprehensive error analysis has never been performed on the data required for an economic assessment, it is not possible to specify the corresponding detailed requirements for data on the distributions of materials.

The why and how of amino acid analytics in cancer diagnostics and therapy.

Science.gov (United States)

Manig, Friederike; Kuhne, Konstantin; von Neubeck, Cläre; Schwarzenbolz, Uwe; Yu, Zhanru; Kessler, Benedikt M; Pietzsch, Jens; Kunz-Schughart, Leoni A

2017-01-20

Pathological alterations in cell functions are frequently accompanied by metabolic reprogramming including modifications in amino acid metabolism. Amino acid detection is thus integral to the diagnosis of many hereditary metabolic diseases. The development of malignant diseases as metabolic disorders comes along with a complex dysregulation of genetic and epigenetic factors affecting metabolic enzymes. Cancer cells might transiently or permanently become auxotrophic for non-essential or semi-essential amino acids such as asparagine or arginine. Also, transformed cells are often more susceptible to local shortage of essential amino acids such as methionine than normal tissues. This offers new points of attacking unique metabolic features in cancer cells. To better understand these processes, highly sensitive methods for amino acid detection and quantification are required. Our review summarizes the main methodologies for amino acid detection with a particular focus on applications in biomedicine and cancer, provides a historical overview of the methodological pre-requisites in amino acid analytics. We compare classical and modern approaches such as the combination of gas chromatography and liquid chromatography with mass spectrometry (GC-MS/LC-MS). The latter is increasingly applied in clinical routine. We therefore illustrate an LC-MS workflow for analyzing arginine and methionine as well as their precursors and analogs in biological material. Pitfalls during protocol development are discussed, but LC-MS emerges as a reliable and sensitive tool for the detection of amino acids in biological matrices. Quantification is challenging, but of particular interest in cancer research as targeting arginine and methionine turnover in cancer cells represent novel treatment strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

The potential of acidophilic macroalgae as part of passive bioremediation technology for acid mine drainage in constructed wetlands

CSIR Research Space (South Africa)

Cheng, Po-Hsun

2012-10-01

Full Text Available macroalgae as part of passive bioremediation technology for acid mine drainage in constructed wetlands PH CHENG1,3, PJ OBERHOLSTER1,2, A-M BOTHA3 1CSIR Natural Resources and the Environment, PO Box 320, Stellenbosch, 7599, South Africa 2Department... of diverse benthic algal species to AMD provides the option to utilise them in AMD remediation as part of passive bioremediation technology in constructed wetlands. The purpose of the study was to investigate the bioaccumulation of metals and trace metal...

Comparative proteomic analyses reveal that the regulators of G-protein signaling proteins regulate amino acid metabolism of the rice blast fungus Magnaporthe oryzae.

Science.gov (United States)

Zhang, Haifeng; Ma, Hongyu; Xie, Xin; Ji, Jun; Dong, Yanhan; Du, Yan; Tang, Wei; Zheng, Xiaobo; Wang, Ping; Zhang, Zhengguang

2014-11-01

The rice blast fungus Magnaporthe oryzae encodes eight regulators of G-protein (GTP-binding protein) signaling (RGS) proteins MoRgs1-MoRgs8 that orchestrate the growth, asexual/sexual production, appressorium differentiation, and pathogenicity. To address the mechanisms by which MoRgs proteins function, we conducted a 2DE proteome study and identified 82 differentially expressed proteins by comparing five ∆Morgs mutants with wild-type Guy11 strain. We found that the abundances of eight amino acid (AA) biosynthesis or degradation associated proteins were markedly altered in five ∆Morgs mutants, indicating one of the main collective roles for the MoRgs proteins is to influence AA metabolism. We showed that MoRgs proteins have distinct roles in AA metabolism and nutrient responses from growth assays. In addition, we characterized MoLys20 (Lys is lysine), a homocitrate synthase, whose abundance was significantly decreased in the ∆Morgs mutants. The ∆Molys20 mutant is auxotrophic for lys and exogenous lys could partially rescue its auxotrophic defects. Deletion of MoLYS20 resulted in defects in conidiation and infection, as well as pathogenicity on rice. Overall, our results indicate that one of the critical roles for MoRgs proteins is to regulate AA metabolism, and that MoLys20 may be directly or indirectly regulated by MoRgs and participated in lys biosynthesis, thereby affecting fungal development and pathogenicity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Engineering biotin prototrophic Corynebacterium glutamicum strains for amino acid, diamine and carotenoid production.

Science.gov (United States)

Peters-Wendisch, P; Götker, S; Heider, S A E; Komati Reddy, G; Nguyen, A Q; Stansen, K C; Wendisch, V F

2014-12-20

The Gram-positive Corynebacterium glutamicum is auxotrophic for biotin. Besides the biotin uptake system BioYMN and the transcriptional regulator BioQ, this bacterium possesses functional enzymes for the last three reactions of biotin synthesis starting from pimeloyl-CoA. Heterologous expression of bioF from the Gram-negative Escherichia coli enabled biotin synthesis from pimelic acid added to the medium, but expression of bioF together with bioC and bioH from E. coli did not entail biotin prototrophy. Heterologous expression of bioWAFDBI from Bacillus subtilis encoding another biotin synthesis pathway in C. glutamicum allowed for growth in biotin-depleted media. Stable growth of the recombinant was observed without biotin addition for eight transfers to biotin-depleted medium while the empty vector control stopped growth after the first transfer. Expression of bioWAFDBI from B. subtilis in C. glutamicum strains overproducing the amino acids l-lysine and l-arginine, the diamine putrescine, and the carotenoid lycopene, respectively, enabled formation of these products under biotin-depleted conditions. Thus, biotin-prototrophic growth and production by recombinant C. glutamicum were achieved. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis, crystal structure and optical property of three coordination polymer constructed from m-phenylenediacrylate acid

Energy Technology Data Exchange (ETDEWEB)

Xiao, YiFan; Wang, TingTing; Zeng, HePing, E-mail: hpzeng@scut.edu.cn

2015-01-15

Three new complexes of the wholly deprotonated flexible ligand m-phenylenediacrylate acid (H{sub 2}mpda), namely, [Zn (mpda) (H{sub 2}O)] [1], [Pr{sub 2}(mpda){sub 2}(H{sub 2}O){sub 2}(CHOO){sub 2}] [2], and [Mn{sub 2}(mpda){sub 2} (H{sub 2}O){sub 4}] [3], were synthesized by the solvothermal reaction. The complexes were characterized by IR spectroscopy, thermogravimetric analysis, and X-ray single-crystal diffraction. A mixed sample [Nd(mpda)(H{sub 2}O)(CHOO)·Pr(mpda)(H{sub 2}O)(CHOO)] [2{sup ]} was also synthesized and studied. Compounds [1] and [2] exhibit a selective sensing function with respect to acetone, and they are a potential luminescent sensory material for the selective detection of Zn{sup 2+} and Ni{sup 2+} ions, respectively. Furthermore, the fluorescent changes of compound [1] upon the addition of cations (Fe{sup 3+} and Zn{sup 2+}, Bi{sup 2+} and Zn{sup 2+}) are utilized to construct two logic gates at the molecular level. - Graphical abstract: Three new complexes of flexible ligand m-phenylenedicarboxylic acid were synthesized by solvothermal reaction. Three metal−organic frameworks exhibiting 1D, 2D, 3D structures, respectively. - Highlights: • Three new complexes of m-phenylenedicarboxylic acid were synthesized. • Three metal−organic frameworks exhibiting 1D, 2D, 3D structures, respectively. • [1] and [2] exhibits a very high quenching effect with acetone. • [1] and [2] are a potential luminescent sensory material for Zn{sup 2+}, Ni{sup 2+} ions. • Two logic gates have been constructed using compound [1].

Corrosion rate of construction materials in hot phosphoric acid with the contribution of anodic polarization

Energy Technology Data Exchange (ETDEWEB)

Kouril, M. [Institute of Chemical Technology, Technicka 5, 166 28 Prague (Czech Republic); Christensen, E. [Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby (Denmark); Eriksen, S.; Gillesberg, B. [Tantaline A/S, Nordborgvej 81, 6430 Nordborg (Denmark)

2012-04-15

The paper is focused on selection of a proper material for construction elements of water electrolysers, which make use of a 85% phosphoric acid as an electrolyte at temperature of 150 C and which might be loaded with anodic polarization up to 2.5 V versus a saturated Ag/AgCl electrode (SSCE). Several grades of stainless steels were tested as well as tantalum, niobium, titanium, nickel alloys and silicon carbide. The corrosion rate was evaluated by means of mass loss at free corrosion potential as well as under various levels of polarization. The only corrosion resistant material in 85% phosphoric acid at 150 C and at polarization of 2.5 V/SSCE is tantalum. In that case, even a gentle cathodic polarization is harmful in such an acidic environment. Hydrogen reduction leads to tantalum hydride formation, to loss of mechanical properties and to complete disintegration of the metal. Contrary to tantalum, titanium is free of any corrosion resistance in hot phosphoric acid. Its corrosion rate ranges from tens of millimetres to metres per year depending on temperature of the acid. Alloy bonded tantalum coating was recognized as an effective corrosion protection for both titanium and stainless steel. Its serviceability might be limited by slow dissolution of tantalum that is in order of units of mm/year. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

The Role of Amino Acid Permeases and Tryptophan Biosynthesis in Cryptococcus neoformans Survival.

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João Daniel Santos Fernandes

Full Text Available Metabolic diversity is an important factor during microbial adaptation to different environments. Among metabolic processes, amino acid biosynthesis has been demonstrated to be relevant for survival for many microbial pathogens, whereas the association between pathogenesis and amino acid uptake and recycling are less well-established. Cryptococcus neoformans is an opportunistic fungal pathogen with many habitats. As a result, it faces frequent metabolic shifts and challenges during its life cycle. Here we studied the C. neoformans tryptophan biosynthetic pathway and found that the pathway is essential. RNAi indicated that interruptions in the biosynthetic pathway render strains inviable. However, auxotroph complementation can be partially achieved by tryptophan uptake when a non preferred nitrogen source and lower growth temperature are applied, suggesting that amino acid permeases may be the target of nitrogen catabolism repression (NCR. We used bioinformatics to search for amino acid permeases in the C. neoformans and found eight potential global permeases (AAP1 to AAP8. The transcriptional profile of them revealed that they are subjected to regulatory mechanisms which are known to respond to nutritional status in other fungi, such as (i quality of nitrogen (Nitrogen Catabolism Repression, NCR and carbon sources (Carbon Catabolism Repression, CCR, (ii amino acid availability in the extracellular environment (SPS-sensing and (iii nutritional deprivation (Global Amino Acid Control, GAAC. This study shows that C. neoformans has fewer amino acid permeases than other model yeasts, and that these proteins may be subjected to complex regulatory mechanisms. Our data suggest that the C. neoformans tryptophan biosynthetic pathway is an excellent pharmacological target. Furthermore, inhibitors of this pathway cause Cryptococcus growth arrest in vitro.

Minor Threonine Dehydratase Encoded Within the Threonine Synthetic Region of Bacillus subtilis1

Science.gov (United States)

Vapnek, Daniel; Greer, Sheldon

1971-01-01

Challenging auxotrophs on metabolites that are precursors of a biosynthetic step involving a mutated enzyme has revealed a new class of suppressor mutations which act by derepressing a minor enzyme activity not normally detected in the wild-type strain. These indirect, partial suppressor mutations which allow isoleucine auxotrophs to grow on homoserine or threonine have been analyzed to determine their effect on enzymes involved in the biosynthesis of these amino acids. It has been found that one class of these suppressor mutations (sprA) leads to the derepression of homoserine kinase, homoserine dehydrogenase, and a minor threonine dehydratase that is not sufficiently active to be detected in the wild-type strain. The gene encoding this second threonine dehydratase activity has been found to be located between the structural genes for homoserine kinase and homoserine dehydrogenase. The results of these experiments indicate that plating of auxotrophs on precursors of a biosynthetic step involving mutated enzymes could prove to be a valuable method for the detection of regulatory mutants as well as a possible tool in studying the evolution of biochemical pathways. PMID:4997544

Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters

KAUST Repository

Kikushima, Kotaro; Holder, Jeffrey C.; Gatti, Michele; Stoltz, Brian M.

2011-01-01

The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a

Drug Delivery and Cosmeceutical Applications of Poly- Lactic Acid Based Novel Constructs - A Review.

Science.gov (United States)

Ruiz-Ruiz, Federico; Mancera-Andrade, Elena Ivonne; Parra-Saldivar, Roberto; Keshavarz, Tajalli; Iqbal, Hafiz M N

2017-01-01

Poly (lactic acid) (PLA) based novel constructs have been engineered for targeted applications in various biomedical sectors of the modern world. In this context, a special focus has been given to pharmaceutical and cosmeceutical industries. In this review, we extensively reviewed, analyzed and compiled salient information from the authentic bibliographic sources including PubMed, Scopus, Elsevier, Springer, Bentham Science and other scientific databases. A focused review question and inclusion/exclusion criterion were adopted to appraise the quality of retrieved peer-reviewed research literature. Recently, bio-based constructs are being engineered for target applications in different bio- and non-bio sectors of the modern world to address the growing human health-related serious concerns. The utilization of properly designed and structured materials thus allows the creation of a well-defined environment that induces a series of directed measures, and so on. Over the last few years, PLA-based novel constructs have received exceptional attention as potential candidates for various biotechnological and biomedical applications at large and drug delivery in particular. Owing to their unique characteristics including biocompatibility, together with the adjustable thermomechanical and tunable control drug release, PLA has raised interesting applications in many sectors of the medical world. So far, many of such PLA-based bio-constructs have been exploited in drug delivery systems, cosmeceutical products, and therapeutic uses. In recent years, many new applications have been reported for PLA-based materials at the micro- and nano- level, resulting in novel requests for specific drug delivery and cosmeceutical sectors. In summary, this review summarizes recent research on different aspects of PLA and PLA-based novel constructs and their potential biomedical applications. Moreover, with the aid of nanotechnology, PLA has made a positive impact in emerging sectors such as

Two multi-dimensional frameworks constructed from zinc coordination polymers with pyridine carboxylic acids

International Nuclear Information System (INIS)

Guo Yuanyuan; Ma Pengtao; Wang Jingping; Niu Jingyang

2011-01-01

Two novel zinc coordination polymers [Zn 2 (H 2 O)L(MoO 4 )] n (1) and [Zn 4 (PO 4 ) 2 L'(H 2 O)] n (2) (H 2 L=2,2'-bipyridine-6.6'-dicarboxylic acid, H 2 L'=2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized and characterized by elemental analyses, IR spectra, UV spectra, single-crystal X-ray diffraction and thermogravimetric analyses. Structural analyses indicate that 1 represents a 2-D sheet structure built by dimeric [Zn 2 L(H 2 O)] 2+ units and MoO 4 2- groups whereas 2 displays an interesting 3-D framework constructed by tetranuclear zinc clusters, L' 2- ligands and PO 4 3- groups. Examination of UV spectra suggests that both 1 and 2 can stably exist in the pH range of 2.45-5.45 and 3.01-8.55 in aqueous solution, respectively. The room-temperature solid-state photoluminescence of 1 and 2 are derived from the intra-ligands π-π* transitions of H 2 L and H 2 L' ligands and the ligand-to-metal-charge-transfer transitions. - Graphical Abstract: Two new transition metal coordination polymers, namely, [Zn 2 (H 2 O)L 1 (MoO 4 )] n (1), [Zn 4 (PO 4 ) 2 L 2 (H 2 O)] n (2) (H 2 L 1 =2,2'-bipyridine-6,6'-dicarboxylic acid, H 2 L 2 =2,2'-bipyridine-4,4'-dicarboxylic acid) have been hydrothermally synthesized. 1 represents a 2-D sheet structure while 2 represents 3-D network. Highlights: →Two new transition metal coordination polymers have been hydrothermally synthesized. → The two compounds have been characterized by elemental analyses, IR, UV spectra, single-crystal X-ray diffraction, thermogravimetric analyses and photoluminescence. → Compound 1 represents a 2-D sheet structure while 2 represents 3-D network.

Auxotrophic recombinant Mycobacterium bovis BCG overexpressing Ag85B enhances cytotoxicity on superficial bladder cancer cells in vitro.

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Begnini, Karine Rech; Rizzi, Caroline; Campos, Vinicius Farias; Borsuk, Sibele; Schultze, Eduarda; Yurgel, Virginia Campello; Nedel, Fernanda; Dellagostin, Odir Antônio; Collares, Tiago; Seixas, Fabiana Kömmling

2013-02-01

BCG therapy remains at the forefront of immunotherapy for treating patients with superficial bladder cancer. The high incidence of local side effects and the presence of non-responder diseases have led to efforts to improve the therapy. Hence, we proposed that an auxotrophic recombinant BCG strain overexpressing Ag85B (BCG ∆leuD/Ag85B), could enhance the cytotoxicity to the human bladder carcinoma cell line 5637. The rBCG was generated using an expression plasmid encoding the mycobacterial antigen Ag85B to transform a BCG ∆leuD strain. The inhibitory effect of BCG ∆leuD/Ag85B on 5637 cells was determined by the MTT method, morphology observation and a LIVE/DEAD assay. Gene expression profiles for apoptotic, cell cycle-related and oxidative stress-related genes were investigated by qRT-PCR. Bax, bcl-2 and p53 induction by BCG ∆leuD/Ag85B treatment was evaluated by Western blotting. BCG ∆leuD/Ag85B revealed a superior cytotoxicity effect compared to the control strains used in this study. The results showed that the expression level of pro-apoptotic and cell cycle-related genes increased after BCG ∆leuD/Ag85B treatment, whereas the mRNA levels of anti-apoptotic genes decreased. Interestingly, BCG ∆leuD/Ag85B also increased the mRNA level of antioxidant enzymes in the bladder cancer cell line. Bax and p53 proteins levels increased following treatment. In conclusion, these results suggest that treatment with BCG ∆leuD/Ag85B enhances cytotoxicity for superficial bladder cancer cells in vitro. Therefore, rBCG therapy may have potential benefits in the treatment of bladder cancer.

Feasibility of protein turnover studies in prototroph Saccharomyces cerevisiae strains.

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Martin-Perez, Miguel; Villén, Judit

2015-04-07

Quantitative proteomics studies of yeast that use metabolic labeling with amino acids rely on auxotrophic mutations of one or more genes on the amino acid biosynthesis pathways. These mutations affect yeast metabolism and preclude the study of some biological processes. Overcoming this limitation, it has recently been described that proteins in a yeast prototrophic strain can also be metabolically labeled with heavy amino acids. However, the temporal profiles of label incorporation under the different phases of the prototroph's growth have not been examined. Labeling trajectories are important in the study of protein turnover and dynamics, in which label incorporation into proteins is monitored across many time points. Here we monitored protein labeling trajectories for 48 h after a pulse with heavy lysine in a yeast prototrophic strain and compared them with those of a lysine auxotrophic yeast. Labeling was successful in prototroph yeast during exponential growth phase but not in stationary phase. Furthermore, we were able to determine the half-lives of more than 1700 proteins during exponential phase of growth with high accuracy and reproducibility. We found a median half-life of 2 h in both strains, which corresponds with the cellular doubling time. Nucleolar and ribosomal proteins showed short half-lives, whereas mitochondrial proteins and other energy production enzymes presented longer half-lives. Except for some proteins involved in lysine biosynthesis, we observed a high correlation in protein half-lives between prototroph and auxotroph strains. Overall, our results demonstrate the feasibility of using prototrophs for proteomic turnover studies and provide a reliable data set of protein half-lives in exponentially growing yeast.

Identification of ergosterol and inhibition of sterol synthesis by Δ5-sterols in GL7, an auxotrophic mutant of yeast

International Nuclear Information System (INIS)

Dhanuka, I.C.

1988-01-01

Synthesis of ergosterol was demonstrated in the GL7 mutant of Saccharomyces cerevisiae. This sterol auxotroph has been thought to lack the ability to synthesize sterols due both to the absence of 2,3-oxidosqualene cyclase and to a heme deficiency eliminating cytochrome P-450 which is required in demethylation at C-14. However, when the exogenous sterol was 5α-cholestan-3β-ol, 5α-cholest-8(14)-en-3β-ol, or 24β-methyl-5α-cholest-8(14)-en-3β-ol, sterol synthesis was found to proceed yielding 1-3 fg/cell of ergosterol. Ergosterol was identified by mass spectroscopy, gas and high performance liquid chromatography, ultraviolet spectroscopy, and radioactive labelling from [ 3 H]acetate. Except for some cholest-5-en-3β-ol (cholesterol) which was derived from the 5α-cholestan-3β-ol, the stanol and the two 8(14)-stenols were not significantly metabolized confirming the absence of an isomerase for migration of the double bond from C-8(14) to C-7. Drastic reduction of ergosterol synthesis to not more than 0.06 fg/cell was observed when the exogenous sterol either had a double bond at C-5, as in the case of cholesterol, or could be metabolized to a sterol with such a bond. Thus, both 5α-cholest-8(9)-en-3β-ol and 5α-cholest-7-en-3β-ol (lathosterol) were converted to cholesta-5,7-dien-3β-ol (7-dehydrocholesterol), and the presence of the latter dienol depressed the level of ergosterol

Lactobacilli evolve by cumulative DNA degeneration

OpenAIRE

Bringel , Françoise; Hubert , Jean-Claude

2004-01-01

International audience; Lactic acid bacteria require rich media since, due to mutations in their biosynthetic genes, they are unable to synthesise numerous amino acids and nucleobases. The extent of genetic lesions was investigated in two biosynthetic pathways for 150 Lactobacillus plantarum isolates from various origins. Arginine biosynthesis and pyrimidine biosynthesis share a common intermediate, carbamoyl phosphate (CP). No pyrimidine auxotrophs were detected and only 7 L. plantarum strai...

Pervasive Selection for Cooperative Cross-Feeding in Bacterial Communities.

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Sebastian Germerodt

2016-06-01

Full Text Available Bacterial communities are taxonomically highly diverse, yet the mechanisms that maintain this diversity remain poorly understood. We hypothesized that an obligate and mutual exchange of metabolites, as is very common among bacterial cells, could stabilize different genotypes within microbial communities. To test this, we developed a cellular automaton to model interactions among six empirically characterized genotypes that differ in their ability and propensity to produce amino acids. By systematically varying intrinsic (i.e. benefit-to-cost ratio and extrinsic parameters (i.e. metabolite diffusion level, environmental amino acid availability, we show that obligate cross-feeding of essential metabolites is selected for under a broad range of conditions. In spatially structured environments, positive assortment among cross-feeders resulted in the formation of cooperative clusters, which limited exploitation by non-producing auxotrophs, yet allowed them to persist at the clusters' periphery. Strikingly, cross-feeding helped to maintain genotypic diversity within populations, while amino acid supplementation to the environment decoupled obligate interactions and favored auxotrophic cells that saved amino acid production costs over metabolically autonomous prototrophs. Together, our results suggest that spatially structured environments and limited nutrient availabilities should facilitate the evolution of metabolic interactions, which can help to maintain genotypic diversity within natural microbial populations.

Multicomponent hydrogen-bonding organic solids constructed from 6-hydroxy-2-naphthoic acid and N-heterocycles: Synthesis, structural characterization and synthon discussion

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Zong, Yingxia; Shao, Hui; Pang, Yanyan; Wang, Debao; Liu, Kang; Wang, Lei

2016-07-01

Seven novel multicomponent crystals involving various substituted organic amine molecules and 6-hydroxy-2-naphthoic acid were prepared and characterized by using single crystal X-ray diffraction, infrared and thermogravimetric analyses (TGA). Crystal structures with 1,4-bis(imidazol) butane (L1) 1, 1,4-bis(imidazol-1-ylmethyl)benzene (L2) 2, 1-phenyl piperazine 3, 2-amino-4-hydroxy-6-methyl pyrimidine 4, 4,4'-bipyridine 5, 5,5'-dimethyl-2,2'-dipyridine 6, 2-amino-4,6-dimethyl pyrimidine 7 were determined. Among the seven molecular complexes, total proton transfer from 6-hydroxy-2-naphthoic acid to coformer has occurred in crystals 1-4, while the remaining were cocrystals. X-ray single-crystal structures of these complexes reveal that strong hydrogen bonding O-H···O/N-H···O/O-H···N and weak C-H···O/C-H···π/π···π intermolecular interactions direct the packing modes of molecular crystals together. The analysis of supramolecular synthons in the present structures shows that some classical supramolecular synthons like pyridine-carboxylic acid heterosynthon R22 (7) and aminopyridine-carboxylic acid heterosynthon R22 (8), are again observed in constructing the hydrogen-bonding networks in this paper. Besides, we noticed that water molecules act as a significant hydrogen-bonding connector in constructing supramolecular architectures of 3, 4, 6, and 7.

The construction of a panel of serum amino acids for the identification of early chronic kidney disease patients.

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Li, Rui; Dai, Jinna; Kang, Hui

2018-03-01

Serum creatinine, urea, and cystatin-c are standardly used for the evaluation of renal function in the clinic. However, some patients have chronic kidney disease but still retain kidney function; a conventional serum index in these patients can be completely normal. Serum amino acid levels can reflect subtle changes in metabolism and are closely related to renal function. Here, we investigated how amino acids change as renal impairment increases. Subjects were divided into three groups by renal function glomerular filtration rate: healthy controls, patients with chronic kidney disease with normal kidney function, and patients with chronic kidney disease with decreased kidney function group. We identified 11 amino acids of interest using LC-MS/MS on MRM (+) mode. Statistical analysis indicated that alanine (ALA), valine (VAL), and tyrosine (TYR) decrease with renal function impairment, whereas phenylalanine (PHE) and citrulline (CIT) increase. We tried to construct a diagnostic model utilizing a combination of amino acids capable of identifying early chronic kidney disease patients. The accuracy, specificity, and sensitivity of the combining predictors were 86.9%, 84.6%, and 90.9%, respectively, which is superior to the reported values for serum creatinine, urea, and cystatin-c. Our data suggest that serum amino acid levels may supply important information for the early detection of chronic kidney disease. We are the first to establish a diagnostic model utilizing serum levels of multiple amino acids for the diagnosis of patients with early-stage chronic kidney disease. © 2017 Wiley Periodicals, Inc.

Staphylococcus aureus utilizes host-derived lipoprotein particles as sources of exogenous fatty acids.

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Delekta, Phillip C; Shook, John C; Lydic, Todd A; Mulks, Martha H; Hammer, Neal D

2018-03-26

Methicillin-resistant Staphylococcus aureus (MRSA) is a threat to global health. Consequently, much effort has focused on the development of new antimicrobials that target novel aspects of S. aureus physiology. Fatty acids are required to maintain cell viability, and bacteria synthesize fatty acids using the type II fatty acid synthesis pathway (FASII). FASII is significantly different from human fatty acid synthesis, underscoring the therapeutic potential of inhibiting this pathway. However, many Gram-positive pathogens incorporate exogenous fatty acids, bypassing FASII inhibition and leaving the clinical potential of FASII inhibitors uncertain. Importantly, the source(s) of fatty acids available to pathogens within the host environment remains unclear. Fatty acids are transported throughout the body by lipoprotein particles in the form of triglycerides and esterified cholesterol. Thus, lipoproteins, such as low-density lipoprotein (LDL) represent a potentially rich source of exogenous fatty acids for S. aureus during infection. We sought to test the ability of LDLs to serve as a fatty acid source for S. aureus and show that cells cultured in the presence of human LDLs demonstrate increased tolerance to the FASII inhibitor, triclosan. Using mass spectrometry, we observed that host-derived fatty acids present in the LDLs are incorporated into the staphylococcal membrane and that tolerance to triclosan is facilitated by the fatty acid kinase A, FakA, and Geh, a triacylglycerol lipase. Finally, we demonstrate that human LDLs support the growth of S. aureus fatty acid auxotrophs. Together, these results suggest that human lipoprotein particles are a viable source of exogenous fatty acids for S. aureus during infection. IMPORTANCE Inhibition of bacterial fatty acid synthesis is a promising approach to combating infections caused by S. aureus and other human pathogens. However, S. aureus incorporates exogenous fatty acids into its phospholipid bilayer. Therefore, the

Random mutagenesis in Corynebacterium glutamicum ATCC 13032 using an IS6100-based transposon vector identified the last unknown gene in the histidine biosynthesis pathway

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Gaigalat Lars

2006-08-01

Full Text Available Abstract Background Corynebacterium glutamicum, a Gram-positive bacterium of the class Actinobacteria, is an industrially relevant producer of amino acids. Several methods for the targeted genetic manipulation of this organism and rational strain improvement have been developed. An efficient transposon mutagenesis system for the completely sequenced type strain ATCC 13032 would significantly advance functional genome analysis in this bacterium. Results A comprehensive transposon mutant library comprising 10,080 independent clones was constructed by electrotransformation of the restriction-deficient derivative of strain ATCC 13032, C. glutamicum RES167, with an IS6100-containing non-replicative plasmid. Transposon mutants had stable cointegrates between the transposon vector and the chromosome. Altogether 172 transposon integration sites have been determined by sequencing of the chromosomal inserts, revealing that each integration occurred at a different locus. Statistical target site analyses revealed an apparent absence of a target site preference. From the library, auxotrophic mutants were obtained with a frequency of 2.9%. By auxanography analyses nearly two thirds of the auxotrophs were further characterized, including mutants with single, double and alternative nutritional requirements. In most cases the nutritional requirement observed could be correlated to the annotation of the mutated gene involved in the biosynthesis of an amino acid, a nucleotide or a vitamin. One notable exception was a clone mutagenized by transposition into the gene cg0910, which exhibited an auxotrophy for histidine. The protein sequence deduced from cg0910 showed high sequence similarities to inositol-1(or 4-monophosphatases (EC 3.1.3.25. Subsequent genetic deletion of cg0910 delivered the same histidine-auxotrophic phenotype. Genetic complementation of the mutants as well as supplementation by histidinol suggests that cg0910 encodes the hitherto unknown

Role of dissimilatory sulfate reduction in wetlands constructed for acid coal mine drainage (AMD) treatment. Master's thesis

International Nuclear Information System (INIS)

Taddeo, F.J.

1991-01-01

Five constructed wetlands with different organic substrates were exposed to the same quantity/quality of acid mine drainage (AMD). During the 16-month exposure to AMD, all wetlands accumulated S in the forms of organic and reduced inorganic S and Fe in the form of iron sulfides. Iron sulfide and probably most of the organic S(C-bonded S) accumulation were end products of bacterial dissimilatory sulfate reduction. Results of study support the notion that sulfate reduction and accumulation of Fe sulfides contribute to Fe retention in wetlands exposed to AMD. Detailed information is provided

Quantitative proteomics by amino acid labeling identifies novel NHR-49 regulated proteins in C. elegans

DEFF Research Database (Denmark)

Fredens, Julius; Færgeman, Nils J.

2012-01-01

in the nematode Caenorhabditis elegans. We have recently shown that C. elegans can be completely labeled with heavy-labeled lysine by feeding worms on prelabeled lysine auxotroph Escherichia coli for just one generation. We applied this methodology to examine the organismal response to functional loss or RNAi...... gene knockdown by RNAi provides a powerful tool with broad implications for C. elegans biology....

Functional analysis of aromatic biosynthetic pathways in Pseudomonas putida KT2440

Science.gov (United States)

Molina‐Henares, M. Antonia; García‐Salamanca, Adela; Molina‐Henares, A. Jesús; De La Torre, Jesús; Herrera, M. Carmen; Ramos, Juan L.; Duque, Estrella

2009-01-01

Summary Pseudomonas putida KT2440 is a non‐pathogenic prototrophic bacterium with high potential for biotechnological applications. Despite all that is known about this strain, the biosynthesis of essential chemicals has not been fully analysed and auxotroph mutants are scarce. We carried out massive mini‐Tn5 random mutagenesis and screened for auxotrophs that require aromatic amino acids. The biosynthesis of aromatic amino acids was analysed in detail including physical and transcriptional organization of genes, complementation assays and feeding experiments to establish pathway intermediates. There is a single pathway from chorismate leading to the biosynthesis of tryptophan, whereas the biosynthesis of phenylalanine and tyrosine is achieved through multiple convergent pathways. Genes for tryptophan biosynthesis are grouped in unlinked regions with the trpBA and trpGDE genes organized as operons and the trpI, trpE and trpF genes organized as single transcriptional units. The pheA and tyrA gene‐encoding multifunctional enzymes for phenylalanine and tyrosine biosynthesis are linked in the chromosome and form an operon with the serC gene involved in serine biosynthesis. The last step in the biosynthesis of these two amino acids requires an amino transferase activity for which multiple tyrB‐like genes are present in the host chromosome. PMID:21261884

Effectiveness of a constructed wetland for acid mine drainage reclamation

International Nuclear Information System (INIS)

Grant, A.J.; Ramey, B.A.; Jarrett, L.; Hart, G.

1993-01-01

Acid mine drainage (AMD) from an abandoned coal mine in southcentral Kentucky had pH levels as low as 2.5 and iron concentrations as high as 630 mg/L. In the summer of 1992, the SCS constructed a wetland system to treat the AMD that involved use of both physical and biological treatment. The AMD was fed into three anoxic limestone beds, followed by an aeration pond, before entering a series of four cattail cells and a polishing pond. Flow of AMD was initiated in the fall of 1992, and chemical and biological monitoring were conducted throughout the winter months. Chemical analysis of the water along the flow path of the AMD during the first six months of operation indicated that the limestone beds improved the pH substantially, and that most of the metals were removed prior to the water entering the cattail cells. The effectiveness of the wetland system to improve water quality also was monitored using the cladoceran (Ceriodaphnia dubia) survival and reproduction test. Determination of toxic levels indicated a substantial improvement in water quality below the limestone beds, and a slight decrease in toxicity throughout the cattail cells. However, toxic levels stayed the same or increased in the polishing pond. Water quality monitoring will continue through the growing season of 1993 to assess the impact of plant growth on the reclamation of the AMD

Functional heterologous protein expression by genetically engineered probiotic yeast Saccharomyces boulardii.

Directory of Open Access Journals (Sweden)

Lauren E Hudson

Full Text Available Recent studies have suggested the potential of probiotic organisms to be adapted for the synthesis and delivery of oral therapeutics. The probiotic yeast Saccharomyces boulardii would be especially well suited for this purpose due to its ability, in contrast to probiotic prokaryotes, to perform eukaryotic post translational modifications. This probiotic yeast thus has the potential to express a broad array of therapeutic proteins. Currently, however, use of wild type (WT S. boulardii relies on antibiotic resistance for the selection of transformed yeast. Here we report the creation of auxotrophic mutant strains of S. boulardii that can be selected without antibiotics and demonstrate that these yeast can express functional recombinant protein even when recovered from gastrointestinal immune tissues in mice. A UV mutagenesis approach was employed to generate three uracil auxotrophic S. boulardii mutants that show a low rate of reversion to wild type growth. These mutants can express recombinant protein and are resistant in vitro to low pH, bile acid salts, and anaerobic conditions. Critically, oral gavage experiments using C57BL/6 mice demonstrate that mutant S. boulardii survive and are taken up into gastrointestinal immune tissues on a similar level as WT S. boulardii. Mutant yeast recovered from gastrointestinal immune tissues furthermore retain expression of functional recombinant protein. These data show that auxotrophic mutant S. boulardii can safely express recombinant protein without antibiotic selection and can deliver recombinant protein to gastrointestinal immune tissues. These auxotrophic mutants of S. boulardii pave the way for future experiments to test the ability of S. boulardii to deliver therapeutics and mediate protection against gastrointestinal disorders.

Functional heterologous protein expression by genetically engineered probiotic yeast Saccharomyces boulardii.

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Hudson, Lauren E; Fasken, Milo B; McDermott, Courtney D; McBride, Shonna M; Kuiper, Emily G; Guiliano, David B; Corbett, Anita H; Lamb, Tracey J

2014-01-01

Recent studies have suggested the potential of probiotic organisms to be adapted for the synthesis and delivery of oral therapeutics. The probiotic yeast Saccharomyces boulardii would be especially well suited for this purpose due to its ability, in contrast to probiotic prokaryotes, to perform eukaryotic post translational modifications. This probiotic yeast thus has the potential to express a broad array of therapeutic proteins. Currently, however, use of wild type (WT) S. boulardii relies on antibiotic resistance for the selection of transformed yeast. Here we report the creation of auxotrophic mutant strains of S. boulardii that can be selected without antibiotics and demonstrate that these yeast can express functional recombinant protein even when recovered from gastrointestinal immune tissues in mice. A UV mutagenesis approach was employed to generate three uracil auxotrophic S. boulardii mutants that show a low rate of reversion to wild type growth. These mutants can express recombinant protein and are resistant in vitro to low pH, bile acid salts, and anaerobic conditions. Critically, oral gavage experiments using C57BL/6 mice demonstrate that mutant S. boulardii survive and are taken up into gastrointestinal immune tissues on a similar level as WT S. boulardii. Mutant yeast recovered from gastrointestinal immune tissues furthermore retain expression of functional recombinant protein. These data show that auxotrophic mutant S. boulardii can safely express recombinant protein without antibiotic selection and can deliver recombinant protein to gastrointestinal immune tissues. These auxotrophic mutants of S. boulardii pave the way for future experiments to test the ability of S. boulardii to deliver therapeutics and mediate protection against gastrointestinal disorders.

Structural characterization of the Mycobacterium tuberculosis biotin biosynthesis enzymes 7,8-diaminopelargonic acid synthase and dethiobiotin synthetase .

Science.gov (United States)

Dey, Sanghamitra; Lane, James M; Lee, Richard E; Rubin, Eric J; Sacchettini, James C

2010-08-10

Mycobacterium tuberculosis (Mtb) depends on biotin synthesis for survival during infection. In the absence of biotin, disruption of the biotin biosynthesis pathway results in cell death rather than growth arrest, an unusual phenotype for an Mtb auxotroph. Humans lack the enzymes for biotin production, making the proteins of this essential Mtb pathway promising drug targets. To this end, we have determined the crystal structures of the second and third enzymes of the Mtb biotin biosynthetic pathway, 7,8-diaminopelargonic acid synthase (DAPAS) and dethiobiotin synthetase (DTBS), at respective resolutions of 2.2 and 1.85 A. Superimposition of the DAPAS structures bound either to the SAM analogue sinefungin or to 7-keto-8-aminopelargonic acid (KAPA) allowed us to map the putative binding site for the substrates and to propose a mechanism by which the enzyme accommodates their disparate structures. Comparison of the DTBS structures bound to the substrate 7,8-diaminopelargonic acid (DAPA) or to ADP and the product dethiobiotin (DTB) permitted derivation of an enzyme mechanism. There are significant differences between the Mtb enzymes and those of other organisms; the Bacillus subtilis DAPAS, presented here at a high resolution of 2.2 A, has active site variations and the Escherichia coli and Helicobacter pylori DTBS have alterations in their overall folds. We have begun to exploit the unique characteristics of the Mtb structures to design specific inhibitors against the biotin biosynthesis pathway in Mtb.

Palladium-Catalyzed Asymmetric Conjugate Addition of Arylboronic Acids to Five-, Six-, and Seven-Membered β-Substituted Cyclic Enones: Enantioselective Construction of All-Carbon Quaternary Stereocenters

KAUST Repository

Kikushima, Kotaro

2011-05-11

The first enantioselective Pd-catalyzed construction of all-carbon quaternary stereocenters via 1,4-addition of arylboronic acids to β-substituted cyclic enones is reported. Reaction of a wide range of arylboronic acids and cyclic enones using a catalyst prepared from Pd(OCOCF(3))(2) and a chiral pyridinooxazoline ligand yields enantioenriched products bearing benzylic stereocenters. Notably, this transformation is tolerant to air and moisture, providing a practical and operationally simple method of synthesizing enantioenriched all-carbon quaternary stereocenters.

The Leishmania nicotinamidase is essential for NAD(+) production and parasite proliferation

OpenAIRE

Gazanion, Elodie; Garcia, Deborah; Silvestre, R.; Gérard, C.; Guichou, J. F.; Labesse, G.; Seveno, Martial; Cordeiro-Da-Silva, A.; Ouaissi, A.; Sereno, Denis; Vergnes, Baptiste

2011-01-01

NAD(+) is a central cofactor that plays important roles in cellular metabolism and energy production in all living cells. Genomics-based reconstruction of NAD(+) metabolism revealed that Leishmania protozoan parasites are NAD(+) auxotrophs. Consequently, these parasites require assimilating NAD(+) precursors (nicotinamide, nicotinic acid, nicotinamide riboside) from their host environment to synthesize NAD(+) by a salvage pathway. Nicotinamidase is a key enzyme of this salvage pathway that ca...

Uptake and Metabolism of Antibiotics Roseoflavin and 8-Demethyl-8-Aminoriboflavin in Riboflavin-Auxotrophic Listeria monocytogenes.

Science.gov (United States)

Matern, Andreas; Pedrolli, Danielle; Großhennig, Stephanie; Johansson, Jörgen; Mack, Matthias

2016-12-01

The riboflavin analogs roseoflavin (RoF) and 8-demethyl-8-aminoriboflavin (AF) are produced by the bacteria Streptomyces davawensis and Streptomyces cinnabarinus Riboflavin analogs have the potential to be used as broad-spectrum antibiotics, and we therefore studied the metabolism of riboflavin (vitamin B 2 ), RoF, and AF in the human pathogen Listeria monocytogenes, a bacterium which is a riboflavin auxotroph. We show that the L. monocytogenes protein Lmo1945 is responsible for the uptake of riboflavin, RoF, and AF. Following import, these flavins are phosphorylated/adenylylated by the bifunctional flavokinase/flavin adenine dinucleotide (FAD) synthetase Lmo1329 and adenylylated by the unique FAD synthetase Lmo0728, the first monofunctional FAD synthetase to be described in bacteria. Lmo1329 generates the cofactors flavin mononucleotide (FMN) and FAD, whereas Lmo0728 produces FAD only. The combined activities of Lmo1329 and Lmo0728 are responsible for the intracellular formation of the toxic cofactor analogs roseoflavin mononucleotide (RoFMN), roseoflavin adenine dinucleotide (RoFAD), 8-demethyl-8-aminoriboflavin mononucleotide (AFMN), and 8-demethyl-8-aminoriboflavin adenine dinucleotide (AFAD). In vivo reporter gene assays and in vitro transcription/translation experiments show that the L. monocytogenes FMN riboswitch Rli96, which controls expression of the riboflavin transport gene lmo1945, is negatively affected by riboflavin/FMN and RoF/RoFMN but not by AF/AFMN. Treatment of L. monocytogenes with RoF or AF leads to drastically reduced FMN/FAD levels. We suggest that the reduced flavin cofactor levels in combination with concomitant synthesis of inactive cofactor analogs (RoFMN, RoFAD, AFMN, and AFAD) explain why RoF and AF contribute to antibiotic activity in L. monocytogenes IMPORTANCE: The riboflavin analogs roseoflavin (RoF) and 8-demethyl-8-aminoriboflavin (AF) are small molecules which are produced by Streptomyces davawensis and Streptomyces cinnabarinus

Neurospora crassa glucose - repressible gene -1(Grg-1) promoter controls the expression of neurospora tyrosinase gene in a clock-controlled manner

International Nuclear Information System (INIS)

Tarawneh, A. K

1997-01-01

In this study sphareroplastes of white Neurospora crassa mutant auxotroph for aromatic am no acids a rom 9 q a-2 inv, was transformed by the pKF-Tyr7-wt DNA construct. This construct contains the promoter of neurospora crassa glucose-repressible gene-1 (G rg-1) usp stream of Neurospora tyrosinase gene. The co transformation of this mutant with pKF-Tyr-7-wt cincture's and the pKAL-1, a plasmid which contains the Neurospora q a-2+ gene transform it to photophor. The transform ant contains the tyrosinase gene which catalyzes the unique step in the synthesis of the black pigment melanin. The activity of the tyrosinase in this transform ant was followed by measuring the absorbance of the dark coloured pigment at 332 nm. The maximum of the tyrosinase activity was shown at 16.36 and 56 hours after the shift of the transformed mycelia from constant light (L L) to constant dark (Dd). The rate of the enzyme activity was changed according to ci radian cycle of 20 hours. This G rg 1/tyrosinase construct provides a good system to study to study the temporal control of gene expression and the interaction between the different environmental c uses that affects gene expression. (author). 20 refs., 4 figs

Utilization of acidic α-amino acids as acyl donors: an effective stereo-controllable synthesis of aryl-keto α-amino acids and their derivatives.

Science.gov (United States)

Wang, Lei; Murai, Yuta; Yoshida, Takuma; Okamoto, Masashi; Tachrim, Zetryana Puteri; Hashidoko, Yasuyuki; Hashimoto, Makoto

2014-05-16

Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

Processing large-diameter poly(L-lactic acid) microfiber mesh/mesenchymal stromal cell constructs via resin embedding: an efficient histologic method

International Nuclear Information System (INIS)

D’Alessandro, Delfo; Danti, Serena; Pertici, Gianni; Moscato, Stefania; Metelli, Maria Rita; Petrini, Mario; Danti, Sabrina; Berrettini, Stefano; Nesti, Claudia

2014-01-01

In this study, we performed a complete histologic analysis of constructs based on large diameter ( > 100 μm) poly-L-lactic acid (PLLA) microfibers obtained via dry-wet spinning and rat Mesenchymal Stromal Cells (rMSCs) differentiated towards the osteogenic lineage, using acrylic resin embedding. In many synthetic polymer-based microfiber meshes, ex post processability of fiber/cell constructs for histologic analysis may face deterring difficulties, leading to an incomplete investigation of the potential of these scaffolds. Indeed, while polymeric nanofiber (fiber diameter = tens of nanometers)/cell constructs can usually be embedded in common histologic media and easily sectioned, preserving the material structure and the antigenic reactivity, histologic analysis of large polymeric microfiber/cell constructs in the literature is really scant. This affects microfiber scaffolds based on FDA-approved and widely used polymers such as PLLA and its copolymers. Indeed, for such constructs, especially those with fiber diameter and fiber interspace much larger than cell size, standard histologic processing is usually inefficient due to inhomogeneous hardness and lack of cohesion between the synthetic and the biological phases under sectioning. In this study, the microfiber/MSC constructs were embedded in acrylic resin and the staining/reaction procedures were calibrated to demonstrate the possibility of successfully employing histologic methods in tissue engineering studies even in such difficult cases. We histologically investigated the main osteogenic markers and extracellular matrix molecules, such as alkaline phosphatase, osteopontin, osteocalcin, TGF-β1, Runx2, Collagen type I and the presence of amorphous, fibrillar and mineralized matrix. Biochemical tests were employed to confirm our findings. This protocol permitted efficient sectioning of the treated constructs and good penetration of the histologic reagents, thus allowing distribution and expression of

Novel genetic tools for diaminopimelic acid selection in virulence studies of Yersinia pestis.

Science.gov (United States)

Bland, David M; Eisele, Nicholas A; Keleher, Lauren L; Anderson, Paul E; Anderson, Deborah M

2011-03-02

Molecular studies of bacterial virulence are enhanced by expression of recombinant DNA during infection to allow complementation of mutants and expression of reporter proteins in vivo. For highly pathogenic bacteria, such as Yersinia pestis, these studies are currently limited because deliberate introduction of antibiotic resistance is restricted to those few which are not human treatment options. In this work, we report the development of alternatives to antibiotics as tools for host-pathogen research during Yersinia pestis infections focusing on the diaminopimelic acid (DAP) pathway, a requirement for cell wall synthesis in eubacteria. We generated a mutation in the dapA-nlpB(dapX) operon of Yersinia pestis KIM D27 and CO92 which eliminated the expression of both genes. The resulting strains were auxotrophic for diaminopimelic acid and this phenotype was complemented in trans by expressing dapA in single and multi-copy. In vivo, we found that plasmids derived from the p15a replicon were cured without selection, while selection for DAP enhanced stability without detectable loss of any of the three resident virulence plasmids. The dapAX mutation rendered Y. pestis avirulent in mouse models of bubonic and septicemic plague which could be complemented when dapAX was inserted in single or multi-copy, restoring development of disease that was indistinguishable from the wild type parent strain. We further identified a high level, constitutive promoter in Y. pestis that could be used to drive expression of fluorescent reporters in dapAX strains that had minimal impact to virulence in mouse models while enabling sensitive detection of bacteria during infection. Thus, diaminopimelic acid selection for single or multi-copy genetic systems in Yersinia pestis offers an improved alternative to antibiotics for in vivo studies that causes minimal disruption to virulence.

Novel genetic tools for diaminopimelic acid selection in virulence studies of Yersinia pestis.

Directory of Open Access Journals (Sweden)

David M Bland

2011-03-01

Full Text Available Molecular studies of bacterial virulence are enhanced by expression of recombinant DNA during infection to allow complementation of mutants and expression of reporter proteins in vivo. For highly pathogenic bacteria, such as Yersinia pestis, these studies are currently limited because deliberate introduction of antibiotic resistance is restricted to those few which are not human treatment options. In this work, we report the development of alternatives to antibiotics as tools for host-pathogen research during Yersinia pestis infections focusing on the diaminopimelic acid (DAP pathway, a requirement for cell wall synthesis in eubacteria. We generated a mutation in the dapA-nlpB(dapX operon of Yersinia pestis KIM D27 and CO92 which eliminated the expression of both genes. The resulting strains were auxotrophic for diaminopimelic acid and this phenotype was complemented in trans by expressing dapA in single and multi-copy. In vivo, we found that plasmids derived from the p15a replicon were cured without selection, while selection for DAP enhanced stability without detectable loss of any of the three resident virulence plasmids. The dapAX mutation rendered Y. pestis avirulent in mouse models of bubonic and septicemic plague which could be complemented when dapAX was inserted in single or multi-copy, restoring development of disease that was indistinguishable from the wild type parent strain. We further identified a high level, constitutive promoter in Y. pestis that could be used to drive expression of fluorescent reporters in dapAX strains that had minimal impact to virulence in mouse models while enabling sensitive detection of bacteria during infection. Thus, diaminopimelic acid selection for single or multi-copy genetic systems in Yersinia pestis offers an improved alternative to antibiotics for in vivo studies that causes minimal disruption to virulence.

HisB as novel selection marker for gene targeting approaches in Aspergillus niger.

Science.gov (United States)

Fiedler, Markus R M; Gensheimer, Tarek; Kubisch, Christin; Meyer, Vera

2017-03-08

For Aspergillus niger, a broad set of auxotrophic and dominant resistance markers is available. However, only few offer targeted modification of a gene of interest into or at a genomic locus of choice, which hampers functional genomics studies. We thus aimed to extend the available set by generating a histidine auxotrophic strain with a characterized hisB locus for targeted gene integration and deletion in A. niger. A histidine-auxotrophic strain was established via disruption of the A. niger hisB gene by using the counterselectable pyrG marker. After curing, a hisB - , pyrG - strain was obtained, which served as recipient strain for further studies. We show here that both hisB orthologs from A. nidulans and A. niger can be used to reestablish histidine prototrophy in this recipient strain. Whereas the hisB gene from A. nidulans was suitable for efficient gene targeting at different loci in A. niger, the hisB gene from A. niger allowed efficient integration of a Tet-on driven luciferase reporter construct at the endogenous non-functional hisB locus. Subsequent analysis of the luciferase activity revealed that the hisB locus is tight under non-inducing conditions and allows even higher luciferase expression levels compared to the pyrG integration locus. Taken together, we provide here an alternative selection marker for A. niger, hisB, which allows efficient homologous integration rates as well as high expression levels which compare favorably to the well-established pyrG selection marker.

Construction and application of a Korean reference panel for imputing classical alleles and amino acids of human leukocyte antigen genes.

Science.gov (United States)

Kim, Kwangwoo; Bang, So-Young; Lee, Hye-Soon; Bae, Sang-Cheol

2014-01-01

Genetic variations of human leukocyte antigen (HLA) genes within the major histocompatibility complex (MHC) locus are strongly associated with disease susceptibility and prognosis for many diseases, including many autoimmune diseases. In this study, we developed a Korean HLA reference panel for imputing classical alleles and amino acid residues of several HLA genes. An HLA reference panel has potential for use in identifying and fine-mapping disease associations with the MHC locus in East Asian populations, including Koreans. A total of 413 unrelated Korean subjects were analyzed for single nucleotide polymorphisms (SNPs) at the MHC locus and six HLA genes, including HLA-A, -B, -C, -DRB1, -DPB1, and -DQB1. The HLA reference panel was constructed by phasing the 5,858 MHC SNPs, 233 classical HLA alleles, and 1,387 amino acid residue markers from 1,025 amino acid positions as binary variables. The imputation accuracy of the HLA reference panel was assessed by measuring concordance rates between imputed and genotyped alleles of the HLA genes from a subset of the study subjects and East Asian HapMap individuals. Average concordance rates were 95.6% and 91.1% at 2-digit and 4-digit allele resolutions, respectively. The imputation accuracy was minimally affected by SNP density of a test dataset for imputation. In conclusion, the Korean HLA reference panel we developed was highly suitable for imputing HLA alleles and amino acids from MHC SNPs in East Asians, including Koreans.

Construction and application of a Korean reference panel for imputing classical alleles and amino acids of human leukocyte antigen genes.

Directory of Open Access Journals (Sweden)

Kwangwoo Kim

Full Text Available Genetic variations of human leukocyte antigen (HLA genes within the major histocompatibility complex (MHC locus are strongly associated with disease susceptibility and prognosis for many diseases, including many autoimmune diseases. In this study, we developed a Korean HLA reference panel for imputing classical alleles and amino acid residues of several HLA genes. An HLA reference panel has potential for use in identifying and fine-mapping disease associations with the MHC locus in East Asian populations, including Koreans. A total of 413 unrelated Korean subjects were analyzed for single nucleotide polymorphisms (SNPs at the MHC locus and six HLA genes, including HLA-A, -B, -C, -DRB1, -DPB1, and -DQB1. The HLA reference panel was constructed by phasing the 5,858 MHC SNPs, 233 classical HLA alleles, and 1,387 amino acid residue markers from 1,025 amino acid positions as binary variables. The imputation accuracy of the HLA reference panel was assessed by measuring concordance rates between imputed and genotyped alleles of the HLA genes from a subset of the study subjects and East Asian HapMap individuals. Average concordance rates were 95.6% and 91.1% at 2-digit and 4-digit allele resolutions, respectively. The imputation accuracy was minimally affected by SNP density of a test dataset for imputation. In conclusion, the Korean HLA reference panel we developed was highly suitable for imputing HLA alleles and amino acids from MHC SNPs in East Asians, including Koreans.

Identification of the enzymatic basis for δ-aminolevulinic acid auxotrophy in a hemA mutant of escherichia coli

International Nuclear Information System (INIS)

Avissar, Y.J.; Beale, S.I.

1989-01-01

The hemA mutation of Escherichia coli K-12 confers a requirement for δ-aminolevulinic acid (ALA). Cell extract prepared from the hemA strain SASX41B was incapable of producing ALA from either glutamate or glutamyl-tRNA, whereas extract of the hem + strain HB101 formed colorimetrically detectable amounts of ALA and transferred label from 1-[ 14 C]glutamate and 3,4-[ 3 H]glutamyl-tRNA to ALA. Extracts of both strains converted glutamate-1-semialdehyde to ALA and were capable of aminoacylating tRNA Glu . Glutamyl-tRNA formed by extracts of both strains could be converted to ALA by the extract of hem + cells. The extract of hemA cells did not convert glutamyl-tRNA formed by either strain to ALA. However, the hemA cell extract, when supplemented in vitro with glutamyl-tRNA dehydrogenase isolated from Chlorella vulgaris cells, formed about as much ALA as did the unsupplemented hem + cell extract. We conclude from these observations that the enzyme activity that is lacking in the ALA auxotrophic strain carrying the hemA mutation is that of glutamyl-tRNA dehydrogenase

The Conjugate Acid-Base Chart.

Science.gov (United States)

Treptow, Richard S.

1986-01-01

Discusses the difficulties that beginning chemistry students have in understanding acid-base chemistry. Describes the use of conjugate acid-base charts in helping students visualize the conjugate relationship. Addresses chart construction, metal ions, buffers and pH titrations, and the organic functional groups and nonaqueous solvents. (TW)

Structural variations and photoluminescent properties of a series of metal-organic frameworks constructed from 5-(4-carboxybenzoylamino)-isophthalic acid

International Nuclear Information System (INIS)

Zhao, Wen; Zhang, Li-Juan; Zhao, Xiao-Li

2013-01-01

Five new metal-organic frameworks (MOFs) with 5-(4-carboxybenzoylamino)-isophthalic acid (H 3 L), namely, [Cd 9 L 6 (DMA) 6 ]·4DMA (1), [Cd 3 L 2 (H 2 O) 9 ]·4H 2 O (2), [LaL(H 2 O) 4 ]·2H 2 O (3), [CeL(H 2 O) 4 ]·H 2 O (4) and [Tb(HL)(H 2 L)(H 2 O) 3 ]·5H 2 O (5) (DMA=N,N-dimethylacetamide), have been synthesized. Complex 1 shows a three-dimensional architecture generated from linkage of Cd–O chains via L 3− ligands. Minor variations in synthetic conditions of 1 afforded 2, which features an interesting 2D→3D catenation architecture containing helical chains. Complexes 3 and 4 are isostructural and each feature a two-dimensional architecture constructed from the linkage of L 3− with Ln 3+ . Complex 5 displays a chain-like structure, of which the most interesting feature is the existence of free carboxylic acid (–COOH) group which may confer unique functionality. Moreover, the investigations of the thermal stability, powder X-ray diffractions and solid-state photoluminescent properties for these crystalline materials have been carried out. - Graphical Abstract: Solvothermal reactions of tricarboxylate ligand H 3 L with Cd 2+ /Ln 3+ has yielded a series of new MOFs containing interesting structural motifs. - Highlights: • A tricarboxylate ligand whose coordinating functionalities are not symmetry equivalent is employed to construct MOFs. • Complex 2 features an interesting 2D→3D catenation architecture containing helical chains. • Complex 3 feature chain-like structure containing free – COOH group, which may confer unique functionality. • Photoluminescent properties and thermal behaviors for 1–5 have been reported

Phylogenetic Analysis of Bacillus subtilis Strains Applicable to Natto (Fermented Soybean) Production ▿

OpenAIRE

Kubo, Yuji; Rooney, Alejandro P.; Tsukakoshi, Yoshiki; Nakagawa, Rikio; Hasegawa, Hiromasa; Kimura, Keitarou

2011-01-01

Spore-forming Bacillus strains that produce extracellular poly-γ-glutamic acid were screened for their application to natto (fermented soybean food) fermentation. Among the 424 strains, including Bacillus subtilis and B. amyloliquefaciens, which we isolated from rice straw, 59 were capable of fermenting natto. Biotin auxotrophism was tightly linked to natto fermentation. A multilocus nucleotide sequence of six genes (rpoB, purH, gyrA, groEL, polC, and 16S rRNA) was used for phylogenetic analy...

Involvement of membrane lipids in radiation damage to potassium-ion permeability of Escherichia coli

Energy Technology Data Exchange (ETDEWEB)

Suzuki, S [Tokyo Univ. (Japan). Inst. for Medical Science; Akamatsu, Y

1978-02-01

Radiation damage to K/sup +/ permeability of an unsaturated fatty acid auxotroph of E.coli grown with oleate or linolenate was investigated at different temperatures. A remarkable effect of radiation was observed at 0/sup 0/C with cells that had been grown in linolenate at 42/sup 0/C. This indicates that, besides protein, membrane lipids at least are involved in the radiation damage. The damage also seems to be affected by the fluidity of membrane lipids.

Material Compatibility Evaluation for DWPF Nitric-Glycolic Acid - Literature Review

Energy Technology Data Exchange (ETDEWEB)

Mickalonis, J. I. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Skidmore, T. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-09-30

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reported corrosion rates and degradation characteristics have shown the following for the materials of construction.

Nucleic Acid-Based Nanoconstructs

Science.gov (United States)

Focuses on the design, synthesis, characterization, and development of spherical nucleic acid constructs as effective nanotherapeutic, single-entity agents for the treatment of glioblastoma multiforme and prostate cancers.

Wet precipitators for sulphuric acid plants

International Nuclear Information System (INIS)

Ojanpera, R.O.

1989-01-01

Both the service requirements and design construction details have changed considerably in recent years for wet electrostatic precipitators as used for gas cleaning ahead of metallurgical sulphuric acid plants. Increased concern over acid quality has resulted in more emphasis on dust efficiencies compared to collection of acid mist. Also, higher static operating pressures have caused large structural loads on casing and internal components. In this paper these two issues are addressed in the following ways: Recognition that all dusts do not collect similarly. The mechanism by which various dusts collect affect the design of the entire wet gas cleaning system. Use of both traditional and newer materials of construction to accommodate the higher design pressures while still maintaining corrosion resistance

The Leishmania nicotinamidase is essential for NAD+ production and parasite proliferation.

Science.gov (United States)

Gazanion, E; Garcia, D; Silvestre, R; Gérard, C; Guichou, J F; Labesse, G; Seveno, M; Cordeiro-Da-Silva, A; Ouaissi, A; Sereno, D; Vergnes, B

2011-10-01

NAD+ is a central cofactor that plays important roles in cellular metabolism and energy production in all living cells. Genomics-based reconstruction of NAD+ metabolism revealed that Leishmania protozoan parasites are NAD+ auxotrophs. Consequently, these parasites require assimilating NAD+ precursors (nicotinamide, nicotinic acid, nicotinamide riboside) from their host environment to synthesize NAD+ by a salvage pathway. Nicotinamidase is a key enzyme of this salvage pathway that catalyses conversion of nicotinamide (NAm) to nicotinic acid (Na), and that is absent in higher eukaryotes. We present here the biochemical and functional characterizations of the Leishmania infantum nicotinamidase (LiPNC1). Generation of Lipnc1 null mutants leads to a decrease in NAD+ content, associated with a metabolic shutdown-like phenotype with an extensive lag phase of growth. Both phenotypes could be rescued by an add-back construct or by addition of exogenous Na. In addition, Lipnc1 null mutants were unable to establish a sustained infection in a murine experimental model. Altogether, these results illustrate that NAD+ homeostasis is a fundamental component of Leishmania biology and virulence, and that NAm constitutes its main NAD+ source in the mammalian host. The crystal structure of LiPNC1 we solved allows now the design of rational inhibitors against this new promising therapeutic target. © 2011 Blackwell Publishing Ltd.

Crystal structures of hibiscus acid and hibiscus acid dimethyl ester isolated from Hibiscus sabdariffa (Malvaceae).

Science.gov (United States)

Zheoat, Ahmed M; Gray, Alexander I; Igoli, John O; Kennedy, Alan R; Ferro, Valerie A

2017-09-01

The biologically active title compounds have been isolated from Hibiscus sabdariffa plants, hibiscus acid as a dimethyl sulfoxide monosolvate [systematic name: (2 S ,3 R )-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carb-oxy-lic acid dimethyl sulfoxide monosolvate], C 6 H 6 O 7 ·C 2 H 6 OS, (I), and hibiscus acid dimethyl ester [systematic name: dimethyl (2 S ,3 R )-3-hy-droxy-5-oxo-2,3,4,5-tetra-hydro-furan-2,3-di-carboxyl-ate], C 8 H 10 O 7 , (II). Compound (I) forms a layered structure with alternating layers of lactone and solvent mol-ecules, that include a two-dimensional hydrogen-bonding construct. Compound (II) has two crystallographically independent and conformationally similar mol-ecules per asymmetric unit and forms a one-dimensional hydrogen-bonding construct. The known absolute configuration for both compounds has been confirmed.

Bio-succinic acid production: Escherichia coli strains design from genome-scale perspectives

Directory of Open Access Journals (Sweden)

Bashir Sajo Mienda

2017-10-01

Full Text Available Escherichia coli (E. coli has been established to be a native producer of succinic acid (a platform chemical with different applications via mixed acid fermentation reactions. Genome-scale metabolic models (GEMs of E. coli have been published with capabilities of predicting strain design strategies for the production of bio-based succinic acid. Proof-of-principle strains are fundamentally constructed as a starting point for systems strategies for industrial strains development. Here, we review for the first time, the use of E. coli GEMs for construction of proof-of-principles strains for increasing succinic acid production. Specific case studies, where E. coli proof-of-principle strains were constructed for increasing bio-based succinic acid production from glucose and glycerol carbon sources have been highlighted. In addition, a propose systems strategies for industrial strain development that could be applicable for future microbial succinic acid production guided by GEMs have been presented.

Bibliography for acid-rock drainage and selected acid-mine drainage issues related to acid-rock drainage from transportation activities

Science.gov (United States)

Bradley, Michael W.; Worland, Scott C.

2015-01-01

Acid-rock drainage occurs through the interaction of rainfall on pyrite-bearing formations. When pyrite (FeS2) is exposed to oxygen and water in mine workings or roadcuts, the mineral decomposes and sulfur may react to form sulfuric acid, which often results in environmental problems and potential damage to the transportation infrastructure. The accelerated oxidation of pyrite and other sulfidic minerals generates low pH water with potentially high concentrations of trace metals. Much attention has been given to contamination arising from acid mine drainage, but studies related to acid-rock drainage from road construction are relatively limited. The U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, is conducting an investigation to evaluate the occurrence and processes controlling acid-rock drainage and contaminant transport from roadcuts in Tennessee. The basic components of acid-rock drainage resulting from transportation activities are described and a bibliography, organized by relevant categories (remediation, geochemical, microbial, biological impact, and secondary mineralization) is presented.

Predicting Three-Dimensional Conformations of Peptides Constructed of Only Glycine, Alanine, Aspartic Acid, and Valine

Science.gov (United States)

Oda, Akifumi; Fukuyoshi, Shuichi

2015-06-01

The GADV hypothesis is a form of the protein world hypothesis, which suggests that life originated from proteins (Lacey et al. 1999; Ikehara 2002; Andras 2006). In the GADV hypothesis, life is thought to have originated from primitive proteins constructed of only glycine, alanine, aspartic acid, and valine ([GADV]-proteins). In this study, the three-dimensional (3D) conformations of randomly generated short [GADV]-peptides were computationally investigated using replica-exchange molecular dynamics (REMD) simulations (Sugita and Okamoto 1999). Because the peptides used in this study consisted of only 20 residues each, they could not form certain 3D structures. However, the conformational tendencies of the peptides were elucidated by analyzing the conformational ensembles generated by REMD simulations. The results indicate that secondary structures can be formed in several randomly generated [GADV]-peptides. A long helical structure was found in one of the hydrophobic peptides, supporting the conjecture of the GADV hypothesis that many peptides aggregated to form peptide multimers with enzymatic activity in the primordial soup. In addition, these results indicate that REMD simulations can be used for the structural investigation of short peptides.

Batch versus continuous feeding strategies for pharmaceutical removal by subsurface flow constructed wetland

International Nuclear Information System (INIS)

Zhang Dongqing; Gersberg, Richard M.; Zhu, Junfei; Hua, Tao; Jinadasa, K.B.S.N.; Tan, Soon Keat

2012-01-01

This study evaluated the effect of continuous and batch feeding on the removal of 8 pharmaceuticals (carbamazepine, naproxen, diclofenac, ibuprofen, caffeine, salicylic acid, ketoprofen and clofibric acid) from synthetic wastewater in mesocosm-scale constructed wetlands (CWs). Both loading modes were operated at hydraulic application rates of 5.6 cm day −1 and 2.8 cm day −1 . Except for carbamazepine, clofibric acid and naproxen, removal in CWs was significantly (p ow ) and removal efficiencies of pharmaceutical compounds in the CWs, showed that pharmaceutical removal efficiency was significantly (p ow value, but not with log K ow value. - Highlights: ► Batch feeding in mesocosm-scale constructed wetlands enhances pharmaceutical removal. ► K values for the 8 pharmaceuticals were in the range of 0.01–0.1 m day −1 . ► The pharmaceutical removal efficiency was inversely correlated with log D ow value. - Batch (drain and fill) feeding in mesocosm-scale constructed wetlands enhances pharmaceutical removal.

The potential of 3-dimensional construct engineered from poly(lactic-co-glycolic acid)/fibrin hybrid scaffold seeded with bone marrow mesenchymal stem cells for in vitro cartilage tissue engineering.

Science.gov (United States)

Abdul Rahman, Rozlin; Mohamad Sukri, Norhamiza; Md Nazir, Noorhidayah; Ahmad Radzi, Muhammad Aa'zamuddin; Zulkifly, Ahmad Hafiz; Che Ahmad, Aminudin; Hashi, Abdurezak Abdulahi; Abdul Rahman, Suzanah; Sha'ban, Munirah

2015-08-01

Articular cartilage is well known for its simple uniqueness of avascular and aneural structure that has limited capacity to heal itself when injured. The use of three dimensional construct in tissue engineering holds great potential in regenerating cartilage defects. This study evaluated the in vitro cartilaginous tissue formation using rabbit's bone marrow mesenchymal stem cells (BMSCs)-seeded onto poly(lactic-co-glycolic acid) PLGA/fibrin and PLGA scaffolds. The in vitro cartilaginous engineered constructs were evaluated by gross inspection, histology, cell proliferation, gene expression and sulphated glycosaminoglycan (sGAG) production at week 1, 2 and 3. After 3 weeks of culture, the PLGA/fibrin construct demonstrated gross features similar to the native tissue with smooth, firm and glistening appearance, superior histoarchitectural and better cartilaginous extracellular matrix compound in concert with the positive glycosaminoglycan accumulation on Alcian blue. Significantly higher cell proliferation in PLGA/fibrin construct was noted at day-7, day-14 and day-21 (ptissue engineered cartilage. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dynamic properties of the Sulfolobus CRISPR/Cas and CRISPR/Cmr systems when challenged with vector-borne viral and plasmid genes and protospacers

DEFF Research Database (Denmark)

Guðbergsdóttir, Sóley Ruth; Deng, Ling; Chen, Zhengjun

2011-01-01

The adaptive immune CRISPR/Cas and CRISPR/Cmr systems of the crenarchaeal thermoacidophile Sulfolobus were challenged by a variety of viral and plasmid genes, and protospacers preceded by different dinucleotide motifs. The genes and protospacers were constructed to carry sequences matching...... individual spacers of CRISPR loci, and a range of mismatches were introduced. Constructs were cloned into vectors carrying pyrE/pyrF genes and transformed into uracil auxotrophic hosts derived from Sulfolobus solfataricus P2 or Sulfolobus islandicus REY15A. Most constructs, including those carrying different...... protospacer mismatches, yielded few viable transformants. These were shown to carry either partial deletions of CRISPR loci, covering a broad spectrum of sizes and including the matching spacer, or deletions of whole CRISPR/Cas modules. The deletions occurred independently of whether genes or protospacers...

Production of γ-linolenic acid and stearidonic acid by Synechococcus sp. PCC7002 containing cyanobacterial fatty acid desaturase genes

Science.gov (United States)

Dong, Xuewei; He, Qingfang; Peng, Zhenying; Yu, Jinhui; Bian, Fei; Li, Youzhi; Bi, Yuping

2016-07-01

Genetic modification is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. Synechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid (GLA) and stearidonic acid (SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6D, Syd15D and Syd6Dd15D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in Synechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.

CONSTRUCTION OF MODULAR FIELD-BIOREACTOR FOR ACID MINE DRAINAGE TREATMENT

Science.gov (United States)

The paper focuses on the improvements to engineered features of a passive technology that has been used for remediation of acid rock drainage (ARD). This passive remedial technology, a sulfate-reducing bacteria (SRB) bioreactor, takes advantage of the ability of SRB that, if sup...

Mannuronic Acids : Reactivity and Selectivity

NARCIS (Netherlands)

Codee, Jeroen D. C.; Walvoort, Marthe T. C.; de Jong, Ana-Rae; Lodder, Gerrit; Overkleeft, Herman S.; van der Marel, Gijsbert A.

2011-01-01

This review describes our recent studies toward the reactivity and selectivity of mannopyranosyl uronic acid donors, which have been found to be very powerful donors for the construction of beta-mannosidic linkages.

New synthesis of poly ortho-methoxyaniline nanostructures and its application to construct modified multi-wall carbon nanotube/graphite paste electrode for simultaneous determination of uric acid and folic acid

Energy Technology Data Exchange (ETDEWEB)

Rajabi, Hossein, E-mail: h.rajabi8086@gmail.com; Noroozifar, Meissam

2017-06-01

Uric acid (UA) and folic acid (FA) are compounds of biomedical interest. In humans, about 70% of daily uric acid disposal occurs via the kidneys, and in 5–25% of humans, impaired renal (kidney) excretion leads to hyperuricemia. Folate is another form folic acid of which is known as, is one of the B vitamins. It is used as a supplement by women to prevent neural tube defects developing during pregnancy. Polyortho-methoxyaniline nanostructures (POMANS) was synthesized with a new two phase (organic-water) synthesis method. The POMANS was characterized using transmission electron microscopy (TEM) and Fourier transform IR (FTIR). This polymer was used to construct a modified multi-wall carbon nanotube, graphite paste electrode (POMANS-MWCNT/GPE). Linear sweep voltammograms (LSV), cyclic voltammetry (CV) and chronoamperometry were used to investigate the suitability of polyortho-methoxyaniline with multi-wall carbon nanotubes paste electrode as a modifier for the electrocatalytic oxidation of UA and FA in aqueous solutions with various pHs. The results showed that POMANS-MWCNT/GPE had high anodic peak currents for the electrooxidation of UA and FA in pH 6.0.Under the optimized conditions, The catalytic peak currents obtained, was linearly dependent on the UA and FA concentrations in the range of 0.6–52 and 0.5–68 μM with two segments and the detection limits 0.157 and 0.113 μM for UA and FA were, respectively. Finally, the proposed method was also examined as a sensitive, simple and inexpensive electrochemical sensor for the simultaneous determination of UA and FA in real samples such as urine and serum. - Highlights: • For the first time, POMANS was synthesized with a new method of two-phase organic & water. • POMANS-MWCNT/GPE was used for simultaneous determination of UA and FA at optimum pH 6.0. • Parameters n and α were also determined for UA and FA. • Electrochemical simultaneous determination of UA and FA with modified electrode real samples.

The use of lactic acid-producing, malic acid-producing, or malic acid-degrading yeast strains for acidity adjustment in the wine industry.

Science.gov (United States)

Su, Jing; Wang, Tao; Wang, Yun; Li, Ying-Ying; Li, Hua

2014-03-01

In an era of economic globalization, the competition among wine businesses is likely to get tougher. Biotechnological innovation permeates the entire world and intensifies the severity of the competition of the wine industry. Moreover, modern consumers preferred individualized, tailored, and healthy and top quality wine products. Consequently, these two facts induce large gaps between wine production and wine consumption. Market-orientated yeast strains are presently being selected or developed for enhancing the core competitiveness of wine enterprises. Reasonable biological acidity is critical to warrant a high-quality wine. Many wild-type acidity adjustment yeast strains have been selected all over the world. Moreover, mutation breeding, metabolic engineering, genetic engineering, and protoplast fusion methods are used to construct new acidity adjustment yeast strains to meet the demands of the market. In this paper, strategies and concepts for strain selection or improvement methods were discussed, and many examples based upon selected studies involving acidity adjustment yeast strains were reviewed. Furthermore, the development of acidity adjustment yeast strains with minimized resource inputs, improved fermentation, and enological capabilities for an environmentally friendly production of healthy, top quality wine is presented.

Biotechnological Potential of Yarrowia lipolytica Grown under Thiamine Limitation

Directory of Open Access Journals (Sweden)

Maria N. Chiglintseva

2012-01-01

Full Text Available During the cultivation of a thiamine-auxotrophic yeast strain Yarrowia lipolytica VKM Y-2412 on ethanol, the growth limitation by thiamine leads to the production of α-ketoglutaric acid. The α-ketoglutaric acid synthesis has been studied in dependence on pH, oxygen supply and ethanol, zinc and iron concentrations. Under optimal conditions, Y. lipolytica produced 88.7 g/L of α-ketoglutaric acid. The culture broth containing α-ketoglutaric acid was subjected to chemical treatment with hydrogen peroxide, which led to the formation of succinic acid in significant quantities (71.7 g/L. Further direct esterification of succinic acid with excess absolute ethanol yielded diethyl succinate. Biomass of Y. lipolytica, a superproducer of α-ketoglutaric acid, was characterized by a high content of protein and essential amino acids, free amino acids, and unusually large amount of γ-aminobutyric acid. The unique amino acid composition of the producer makes it possible to use this biomass as a component of parenteral nutrition mixtures and as a basis for neuroleptics.

Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

Science.gov (United States)

Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves II, H. James

2015-01-01

Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or “chemistry space.” Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set. PMID:25802223

Extraordinarily adaptive properties of the genetically encoded amino acids.

Science.gov (United States)

Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves, H James

2015-03-24

Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or "chemistry space." Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set.

Identification of key amino acid residues in the hTGR5-nomilin interaction and construction of its binding model.

Science.gov (United States)

Sasaki, Takashi; Mita, Moeko; Ikari, Naho; Kuboyama, Ayane; Hashimoto, Shuzo; Kaneko, Tatsuya; Ishiguro, Masaji; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

2017-01-01

TGR5, a member of the G protein-coupled receptor (GPCR) family, is activated by bile acids. Because TGR5 promotes energy expenditure and improves glucose homeostasis, it is recognized as a key target in treating metabolic diseases. We previously showed that nomilin, a citrus limonoid, activates TGR5 and confers anti-obesity and anti-hyperglycemic effects in mice. Information on the TGR5-nomilin interaction regarding molecular structure, however, has not been reported. In the present study, we found that human TGR5 (hTGR5) shows higher nomilin responsiveness than does mouse TGR5 (mTGR5). Using mouse-human chimeric TGR5, we also found that three amino acid residues (Q77ECL1, R80ECL1, and Y893.29) are important in the hTGR5-nomilin interaction. Based on these results, an hTGR5-nomilin binding model was constructed using in silico docking simulation, demonstrating that four hydrophilic hydrogen-bonding interactions occur between nomilin and hTGR5. The binding mode of hTGR5-nomilin is vastly different from those of other TGR5 agonists previously reported, suggesting that TGR5 forms various binding patterns depending on the type of agonist. Our study promotes a better understanding of the structure of TGR5, and it may be useful in developing and screening new TGR5 agonists.

Increase of radiation damage to potassium-ion permeability in E. coli cells with decrease in membrane fluidity

International Nuclear Information System (INIS)

Suzuki, S.

1980-01-01

Membrane lipids of an auxotroph of E. coli requiring unsaturated fatty acid were manipulated by supplementing the growth medium with unsaturated fatty acids of different chain lengths and/or configurations, and the radiation damage to K + -permeability of the resulting modified cells was investigated in relation with factors influencing membrane fluidity, such as temperature and procaine. Radiation had greater effects on membranes supplemented with unsaturated fatty acids of the trans configuration with a longer chain than on those of the cis configuration with a shorter chain. Radiation damage also increased with decrease in temperature. Furthermore, procaine-treated membranes showed increased resistance to radiation. All these results indicate that the damage was affected by the physical character of membrane lipids and that it was greater in membranes with decreased fluidity. (author)

Chimera: construction of chimeric sequences for phylogenetic analysis

NARCIS (Netherlands)

Leunissen, J.A.M.

2003-01-01

Chimera allows the construction of chimeric protein or nucleic acid sequence files by concatenating sequences from two or more sequence files in PHYLIP formats. It allows the user to interactively select genes and species from the input files. The concatenated result is stored to one single output

Application of Health Belief Model\\'s constructs for predicting regular consumption of folic acid supplements in pregnant women referred to Borazjan’s health centers in 2014-15

Directory of Open Access Journals (Sweden)

Zohre kafaee

2016-04-01

Full Text Available Background: One of the most common disorders in pregnancy is Folic Acid deficiency and its complications. The aim of this study was to examine the predictors of regular use of folic acid supplements based on HBM in pregnant women referred to Borazjan’s health centers. Material and Methods: In this cross-sectional study, 228 pregnant women or women with planning of pregnancy referred to health centers of Borazjan with random sampling method evaluated. Data was collected with questionnaire in 4 parts included demographic characteristics, knowledge, health belief model constructs and questions about folic acid supplement use. Data was analyzed by SPSS software with using appropriate statistical tests. Results: The mean age of samples was 27.4±5.41. 144 patients (63.2% consumed Folic Acid pills regularly, and 84 patients (36.8% had irregular use. The awareness of folic acid in 22.8% of women was good, 59.6%  and 17.5% of samples had intermediate and poor awareness, respectively. The perceived barriers (P<0.001, perceived benefits (P=0.002 and self-efficacy (P<0.001 had relation with consumption of folic acid and among demographic variables, only education level (P=0.04 had relation with the consumption of pills. In logistic regression perceived barriers was only predictor. Age and educational level had indirect effect in regular consume pill. Conclusion: Perceived barriers was strongest predictors of folic acid use, therefore intervention based on health belief model, with emphasis on reducing barriers is necessary for improving the use of this medicine during pregnancy.

Identification of novel protein functions and signaling mechanisms by genetics and quantitative phosphoproteomics in Caenorhabditis elegans

DEFF Research Database (Denmark)

Fredens, Julius; Engholm-Keller, Kasper; Møller-Jensen, Jakob

2014-01-01

knockdown by feeding the nematode on pre-labeled lysine auxotroph Escherichia coli. In this chapter, we describe in details the generation of the E. coli strain, incorporation of heavy isotope-labeled lysine in C. elegans, and the procedure for a comprehensive global phosphoproteomic experiment.......Stable isotope labeling by amino acids combined with mass spectrometry is a widely used methodology for measuring relative changes in protein and phosphorylation levels at a global level. We have applied this method to the model organism Caenorhabditis elegans in combination with RNAi-mediated gene...

Soybean phytase and nucleic acid encoding the same

OpenAIRE

1999-01-01

Isolated soybean phytase polypeptides and isolated nucleic acids encoding soybean phytases are provided. The invention is also directed to nucleic acid expression constructs, vectors, and host cells comprising the isolated soybean phytase nucleic acids, as well as methods for producing recombinant and non-recombinant purified soybean phytase. The invention also relates to transgenic plants expressing the soybean phytase, particularly expression under seed-specific expression control elements.

Using Willie's Acid-Base Box for Blood Gas Analysis

Science.gov (United States)

Dietz, John R.

2011-01-01

In this article, the author describes a method developed by Dr. William T. Lipscomb for teaching blood gas analysis of acid-base status and provides three examples using Willie's acid-base box. Willie's acid-base box is constructed using three of the parameters of standard arterial blood gas analysis: (1) pH; (2) bicarbonate; and (3) CO[subscript…

[Construction of a recombinant Escherichia coli BL21/ pET-28a-lpgad and the optimization of transformation conditions for the efficient production of gamma-aminobutyric acid].

Science.gov (United States)

Tian, Lingzhi; Xu, Meijuan; Rao, Zhiming

2012-01-01

In order to enhance gamma-aminobutyric acid production from L-glutamate efficiently, we amplified the key enzyme glutamate decarboxylase (GAD) encoding gene lpgad from the strain Lactobacillus plantarum GB 01-21 which was obtained by way of multi-mutagenesis and overexpressed it in E. coli BL21. Then we purified GAD by Ni-NTA affinity chromatography and characterized the enzyme to optimize the conditions of the whole-cell transformation. The results showed that the recombinant E. coli BL21 (pET-28a-lpgad) produced 8.53 U/mg GAD, which was increased by 3.24 fold compared with the GAD activity in L. plantarum. The optimum pH and temperature of the enzyme were pH 4.8 and 37 degrees C, respectively. At the same time, we found that Ca2+ and Mg2+ could increase the activity significantly. Based on this, we investigated gamma-aminobutyric acid transformation in 5 L fermentor under the optimum transformation conditions. Accordingly, the yield of gamma-aminobutyric acid was 204.5 g/L at 24 h when the 600 g L-glutamate was added and the mole conversion rate had reached 97.92%. The production of gamma-aminobutyric acid was improved by 42.5% compared with that under the unoptimized transformation conditions. This paved a way for the gamma-aminobutyric acid construction of the industrial applications.

Integrated gasification combined cycle for acid rain control

Energy Technology Data Exchange (ETDEWEB)

Simbeck, D.R.; Dickenson, R.L.

1986-10-01

The role of integrated coal gasification combined-cycle power plants in the abatement of emission of SO/sub 2/ and NO/sub 2/ which lead to acid rain is discussed. The economics of this IGCC approach are assessed for a nominal 500 MW plant size. Phased construction of IGCC plants is recommended as a means of reducing SO/sub 2/ and NO/sub x/ emissions noting that high-sulfur coals could continue to be used. It is also noted that phased construction IGCC is the only acid rain control technology that greatly reduces NO/sub x/. 17 references.

Waste acid/metal solution reduction and recovery by vacuum distillation

International Nuclear Information System (INIS)

Jones, E.O.; Wilcox, W.A.; Johnson, N.T.; Bowdish, F.W.

1995-01-01

Processes involving distillation under reduced pressure were developed at the Pacific Northwest Laboratory several years ago to recover spent acid solutions generated during the manufacture of nuclear fuel for the N-Reactor at the Hanford site. Following construction and testing of a pilot-plant, the technology was licensed to Viatec Recovery Systems, Inc. for commercialization. The technology developed included specialized distillation and rectification of volatile acids, removal of water and/or volatile acid from sulfuric acid, and precipitation of salts. A key feature of the Waste Acid Detoxification and Reclamation (WADR) technology is the development and use of advanced thermoplastic and fluoropolymer materials of construction in all critical process equipment. The technology was then expanded to include crystallization to recover metal salts for possible reuse. Economic and environmental advantages of the procedures include recovery of acids for reuse, simplification or elimination of the disposal of waste solutions, and possible recovery of metals. Industries expected to benefit from such applications include galvanizing, electroplating, sand leaching and any where metals are cleaned in acid solutions. Currently a modular system has been assembled for recovery of several different spent acid solutions

The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.

Science.gov (United States)

Ozeryanskii, Valery A; Gorbacheva, Anastasia Yu; Pozharskii, Alexander F; Vlasenko, Marina P; Tereznikov, Alexander Yu; Chernov'yants, Margarita S

2015-08-21

The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties.

A novel method for the biosynthesis of deuterated proteins with selective protonation at the aromatic rings of Phe, Tyr and Trp

International Nuclear Information System (INIS)

Rajesh, Sundaresan; Nietlispach, Daniel; Nakayama, Hiroshi; Takio, Koji; Laue, Ernest D.; Shibata, Takehiko; Ito, Yutaka

2003-01-01

A novel biosynthetic strategy is described for the preparation of deuterated proteins containing protons at the ring carbons of Phe, Tyr and Trp, using the aromatic amino acid precursor shikimic acid. Specific protonation at aromatic side chains, with complete deuteration at C α/β positions was achieved in proteins overexpressed in bacteria grown in shikimate-supplemented D 2 O medium. Co-expression of a shikimate transporter in prototrophic bacteria resulted in protonation levels of 62-79%, whereas complete labeling was accomplished using shikimate auxotrophic bacteria. Our labeling protocol permits the measurement of important aromatic side chain derived distance restraints in perdeuterated proteins that could be utilized to enhance the accuracy of NMR structures calculated using low densities of NOEs from methyl selectively protonated samples

Synthesis, Structural Characterization and Catalytic Activity of A Cu(II Coordination Polymer Constructed from 1,4-Phenylenediacetic Acid and 2,2’-Bipyridine

Directory of Open Access Journals (Sweden)

Wang Li-Hua

2017-04-01

Full Text Available In order to study the catalytic activity of Cu(II coordination polymer material, a novel 1D chained Cu(II coordination polymer material, [CuL(bipy(H2O5]n (A1 (H2L = 1,4-phenylenediacetic acid, bipy = 2,2’-bipyridine, has been prepared by the reaction of 1,4-phenylenediacetic acid, 2,2’-bipyridine, Cu(CH3COO2·H2O and NaOH. The composition of A1 was determined by elemental analysis, IR spectra and single crystal X-ray diffraction. The results of characterization show that each Cu(II atom adopts six-coordination and forms a distorted octahedral configuration. The catalytic activity and reusability of A1 catalyst for A3 coupling reaction of benzaldehyde, piperidine, and phenylacetylene have been investigated. And the results show that the Cu(II complex catalyst has good catalytic activity with a maximum yield of 54.3% and stability. Copyright © 2017 BCREC GROUP. All rights reserved Received: 21st October 2016; Revised: 17th November 2016; Accepted: 22nd November 2016 How to Cite: Li-Hua, W., Lei, L., Xin, W. (2017. Synthesis, Structural Characterization and Catalytic Activity of A Cu(II Coordination Polymer Constructed from 1,4-Phenylenediacetic Acid and 2,2’-Bipyridine. Bulletin of Chemical Reaction Engineering & Catalysis, 12 (1: 113-118 (doi:10.9767/bcrec.12.1.735.113-118 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.12.1.735.113-118

Concentration characteristics of VOCs and acids/bases in the gas phase and water-soluble ions in the particle phase at an electrical industry park during construction and mass production.

Science.gov (United States)

Tsai, Jiun H; Huang, Yao S; Shieh, Zhu X; Chiang, Hung L

2011-01-01

The electronics industry is a major business in the Central Taiwan Science Park (CTSP). Particulate samples and 11 water-soluble ionic species in the particulate phase were measured by ionic chromatography (IC). Additionally, acid and base gases were sampled by denuder absorption and analyzed by IC. Volatile organic compounds (VOCs) were collected in stainless-steel canisters four times daily and analyzed via gas chromatography/mass spectrometry. Ozone formation potential (OFP) was measured using maximum increment reactivity. In addition, airborne pollutants during (1) construction and (2) mass production were measured. Particulate matter concentration did not increase significantly near the optoelectronic plant during construction, but it was higher than during mass production. SO(2), HNO(2) and NH(3) were the dominant gases in the denuder absorption system. Nitrate, sulfate, and ammonium ions predominated both in PM(2.5) and PM(10-2.5); but calcium ion concentration was significantly higher in PM(10-2.5) samples during construction. Toluene, propane, isopentane, and n-butane may have come from vehicle exhaust. Construction equipment emitted high concentrations of ethylbenzene, m-xylene, p-xylene, o-xylene, 1,2,4-trimethylbenzene, and toluene. During mass production, methyl ethyl ketone), acetone and ethyl acetate were significantly higher than during construction, although there was continuous rain. The aromatic group constituted >50% of the VOC concentration totals and contributed >70% of OFP.

Ligand-Enabled γ-C–H Olefination and Carbonylation: Construction of β-Quaternary Carbon Centers

Science.gov (United States)

2015-01-01

Monoselective γ-C–H olefination and carbonylation of aliphatic acids has been accomplished by using a combination of a quinoline-based ligand and a weakly coordinating amide directing group. The reaction provides a new route for constructing richly functionalized all-carbon quaternary carbon centers at the β-position of aliphatic acids. PMID:24666182

Morphology-dependent Electrochemical Enhancements of Porous Carbon as Sensitive Determination Platform for Ascorbic Acid, Dopamine and Uric Acid

Science.gov (United States)

Cheng, Qin; Ji, Liudi; Wu, Kangbing; Zhang, Weikang

2016-02-01

Using starch as the carbon precursor and different-sized ZnO naoparticles as the hard template, a series of porous carbon materials for electrochemical sensing were prepared. Experiments of scanning electron microscopy, transmission electron microscopy and Nitrogen adsorption-desorption isotherms reveal that the particle size of ZnO has big impacts on the porous morphology and surface area of the resulting carbon materials. Through ultrasonic dispersion of porous carbon and subsequent solvent evaporation, different sensing interfaces were constructed on the surface of glassy carbon electrode (GCE). The electrochemical behaviors of ascorbic acid (AA), dopamine (DA) and uric acid (UA) were studied. On the surface of porous carbon materials, the accumulation efficiency and electron transfer ability of AA, DA and UA are improved, and consequently their oxidation signals enhance greatly. Moreover, the interface enhancement effects of porous carbon are also controlled by the particle size of hard template. The constructed porous carbon interface displays strong signal amplification ability and holds great promise in constructing a sensitive platform for the simultaneous determination of AA, DA and UA.

[Expression of the genes for lysine biosynthesis of Bacillus subtilis in Escherichia coli cells].

Science.gov (United States)

Shevchenko, T N; Okunev, O V; Aleksieva, Z M; Maliuta, S S

1984-01-01

Hybrid plasmids pLRS33 and pLRB4 containing Bac. subtilis genes coding lysin biosynthesis were subjected to genetical analysis. It is shown that after pLRS33- and pLRB4- transformation of E. coli strains, auxotrophic relative to lysin and diaminopimelic acid, there occurs complementation of dapA, dapB, dapC, dapD, dapE, lysA mutations by plasmid pLRS33 and of dapC, dapB, lysA mutations by plasmid pLRB4. The plasmids are studied for their influence on the level of lysin and its precurror synthesis in E. coli strains.

Amino Acid Signatures to Evaluate the Beneficial Effects of Weight Loss

DEFF Research Database (Denmark)

Geidenstam, Nina; Magnusson, Martin; Danielsson, Anders P H

2017-01-01

-associated amino acids from the MDC-CC, alanine, isoleucine, tyrosine, phenylalanine, and glutamate decreased after weight loss, while asparagine increased after weight maintenance. These changes were validated in the replication cohort. Scores that were constructed based on obesity-associated amino acids...

Determination and modeling of binary and ternary solid-liquid phase equilibrium for the systems formed by 3,5-dinitrobenzoic acid, m-nitrobenzoic acid and acetone

International Nuclear Information System (INIS)

Li, Xinbao; Du, Cunbin; Zhao, Hongkun

2017-01-01

Highlights: • The solubility of 3,5-dinitrobenzoic acid in acetone was determined. • Solubility of m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone was determined. • Three ternary phase diagrams were constructed for the ternary system. • The ternary phase diagrams were calculated by Wilson model and NRTL model. - Abstract: The solubility of 3,5-dinitrobenzoic acid in acetone at the temperatures ranging from (283.15 to 318.15) K and the mutual solubility of the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system at (283.15, 298.15 and 313.15) K were determined experimentally by using the isothermal saturation method under atmosphere pressure (101.2 kPa). Three isothermal ternary phase diagrams were constructed according to the measured mutual solubility data. In each ternary phase diagram, there was one co-saturated point, two boundary curves, and three crystalline regions. The modified Apelblat equation, λh equation, NRTL model and Wilson model were used to correlate the solubility of 3,5-dinitrobenzoic acid in acetone; and the NRTL and Wilson models, the mutual solubility for the ternary m-nitrobenzoic acid + 3,5-dinitrobenzoic acid + acetone system. The value of root-mean-square deviation (RMSD) was 8.53 × 10 −4 for the binary system of 3,5-dinitrobenzoic acid + acetone; and the largest value of RMSD was 81.08 × 10 −4 for the ternary system.

Material compatibility evaluation for DWPF nitric-glycolic acid-literature review

Energy Technology Data Exchange (ETDEWEB)

Mickalonis, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Skidmore, E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2013-06-01

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid.

Production of caffeoylmalic acid from glucose in engineered Escherichia coli.

Science.gov (United States)

Li, Tianzhen; Zhou, Wei; Bi, Huiping; Zhuang, Yibin; Zhang, Tongcun; Liu, Tao

2018-07-01

To achieve biosynthesis of caffeoylmalic acid from glucose in engineered Escherichia coli. We constructed the biosynthetic pathway of caffeoylmalic acid in E. coli by co-expression of heterologous genes RgTAL, HpaBC, At4CL2 and HCT2. To enhance the production of caffeoylmalic acid, we optimized the tyrosine metabolic pathway of E. coli to increase the supply of the substrate caffeic acid. Consequently, an E. coli-E. coli co-culture system was used for the efficient production of caffeoylmalic acid. The final titer of caffeoylmalic acid reached 570.1 mg/L. Microbial production of caffeoylmalic acid using glucose has application potential. In addition, microbial co-culture is an efficient tool for producing caffeic acid esters.

Signalling network construction for modelling plant defence response.

Directory of Open Access Journals (Sweden)

Dragana Miljkovic

Full Text Available Plant defence signalling response against various pathogens, including viruses, is a complex phenomenon. In resistant interaction a plant cell perceives the pathogen signal, transduces it within the cell and performs a reprogramming of the cell metabolism leading to the pathogen replication arrest. This work focuses on signalling pathways crucial for the plant defence response, i.e., the salicylic acid, jasmonic acid and ethylene signal transduction pathways, in the Arabidopsis thaliana model plant. The initial signalling network topology was constructed manually by defining the representation formalism, encoding the information from public databases and literature, and composing a pathway diagram. The manually constructed network structure consists of 175 components and 387 reactions. In order to complement the network topology with possibly missing relations, a new approach to automated information extraction from biological literature was developed. This approach, named Bio3graph, allows for automated extraction of biological relations from the literature, resulting in a set of (component1, reaction, component2 triplets and composing a graph structure which can be visualised, compared to the manually constructed topology and examined by the experts. Using a plant defence response vocabulary of components and reaction types, Bio3graph was applied to a set of 9,586 relevant full text articles, resulting in 137 newly detected reactions between the components. Finally, the manually constructed topology and the new reactions were merged to form a network structure consisting of 175 components and 524 reactions. The resulting pathway diagram of plant defence signalling represents a valuable source for further computational modelling and interpretation of omics data. The developed Bio3graph approach, implemented as an executable language processing and graph visualisation workflow, is publically available at http://ropot.ijs.si/bio3graph/and can be

A construction process model for implementing constructability in construction

NARCIS (Netherlands)

Langkemper, J.; Al-Jibouri, S.; Reymen, I.M.M.J.; Maas, G.J.; Gassel, van F.

2003-01-01

In construction, failure of design professionals to consider how a builder will implement the design can result in scheduling problems, cost escalation, delays and disputes during the construction process. The integration of construction knowledge and experience during planning and design is termed

Three coordination polymers constructed from 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid: Synthesis, crystal structure and properties

Science.gov (United States)

Zhai, Dandan; Sun, Wujuan; Fan, Fei; Liao, Xuzhao; Chen, Sanping; Yang, Xuwu

2017-04-01

Three new coordination polymers, namely, {[Co2(TPA)(μ3-O)3]·0.5DMA}n (1), {[Co(H2TPA)(bibp)(H2O)3]·H2O}n (2) and {[Cd3(TPA)2(phen)4]·4H2O}n (3), (H3TPA = 5-(4-(tetrazol-5-yl)phenyl)isophthalic acid, bibp = 4,4'-bis(imidazolyl)biphenyl, phen = 1,10-phenanthroline and DMA = N,N-dimethylacetamide), have been synthesized under solvothermal conditions and structurally characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction analysis. Polymer 1 exhibits a three-dimensional (3D) structure constructed from 5-connected secondary building units (SBUs) [Co3(μ3-O)] and 3-connected H3TPA ligands. Polymer 2 has a 1D zigzag polymer chain connected by H3TPA and bibp ligands. Polymer 3 features an unusual 3D framework with a (3,4,2)-connected {4; 6;8}{4; 62;83} topology. Moreover, the thermal stabilities of 1-3 and photoluminescence properties of 3 have been investigated. Magnetic susceptibility measurements indicate that polymers 1-2 display antiferromagnetic exchange properties.

Acid-base homeostasis in the human system

Science.gov (United States)

White, R. J.

1974-01-01

Acid-base regulation is a cooperative phenomena in vivo with body fluids, extracellular and intracellular buffers, lungs, and kidneys all playing important roles. The present account is much too brief to be considered a review of present knowledge of these regulatory systems, and should be viewed, instead, as a guide to the elements necessary to construct a simple model of the mutual interactions of the acid-base regulatory systems of the body.

Materials and methods for efficient lactic acid production

Science.gov (United States)

Zhou, Shengde; Ingram, Lonnie O& #x27; Neal; Shanmugam, Keelnatham T; Yomano, Lorraine; Grabar, Tammy B; Moore, Jonathan C

2013-04-23

The present invention provides derivatives of Escherichia coli constructed for the production of lactic acid. The transformed E. coli of the invention are prepared by deleting the genes that encode competing pathways followed by a growth-based selection for mutants with improved performance. These transformed E. coli are useful for providing an increased supply of lactic acid for use in food and industrial applications.

p21-ras effector domain mutants constructed by "cassette" mutagenesis

DEFF Research Database (Denmark)

Stone, J C; Vass, W C; Willumsen, B M

1988-01-01

A series of mutations encoding single-amino-acid substitutions within the v-rasH effector domain were constructed, and the ability of the mutants to induce focal transformation of NIH 3T3 cells was studied. The mutations, which spanned codons 32 to 40, were made by a "cassette" mutagenesis...

A comparison of charcoal- and slag-based constructed wetlands for ...

African Journals Online (AJOL)

Subsurface-flow constructed wetlands (CW) with charcoal- or slag-based bed matrices were investigated for their potential use in remediating acid mine drainage (AMD). A CW is effectively a reactor in which some components of the wastewater are broken down by the organisms occurring within the CW, whilst others may ...

Repression of branched-chain amino acid synthesis in Staphylococcus aureus is mediated by isoleucine via CodY, and by a leucine-rich attenuator peptide.

Science.gov (United States)

Kaiser, Julienne C; King, Alyssa N; Grigg, Jason C; Sheldon, Jessica R; Edgell, David R; Murphy, Michael E P; Brinsmade, Shaun R; Heinrichs, David E

2018-01-01

Staphylococcus aureus requires branched-chain amino acids (BCAAs; isoleucine, leucine, valine) for protein synthesis, branched-chain fatty acid synthesis, and environmental adaptation by responding to their availability via the global transcriptional regulator CodY. The importance of BCAAs for S. aureus physiology necessitates that it either synthesize them or scavenge them from the environment. Indeed S. aureus uses specialized transporters to scavenge BCAAs, however, its ability to synthesize them has remained conflicted by reports that it is auxotrophic for leucine and valine despite carrying an intact BCAA biosynthetic operon. In revisiting these findings, we have observed that S. aureus can engage in leucine and valine synthesis, but the level of BCAA synthesis is dependent on the BCAA it is deprived of, leading us to hypothesize that each BCAA differentially regulates the biosynthetic operon. Here we show that two mechanisms of transcriptional repression regulate the level of endogenous BCAA biosynthesis in response to specific BCAA availability. We identify a trans-acting mechanism involving isoleucine-dependent repression by the global transcriptional regulator CodY and a cis-acting leucine-responsive attenuator, uncovering how S. aureus regulates endogenous biosynthesis in response to exogenous BCAA availability. Moreover, given that isoleucine can dominate CodY-dependent regulation of BCAA biosynthesis, and that CodY is a global regulator of metabolism and virulence in S. aureus, we extend the importance of isoleucine availability for CodY-dependent regulation of other metabolic and virulence genes. These data resolve the previous conflicting observations regarding BCAA biosynthesis, and reveal the environmental signals that not only induce BCAA biosynthesis, but that could also have broader consequences on S. aureus environmental adaptation and virulence via CodY.

Repression of branched-chain amino acid synthesis in Staphylococcus aureus is mediated by isoleucine via CodY, and by a leucine-rich attenuator peptide.

Directory of Open Access Journals (Sweden)

Julienne C Kaiser

2018-01-01

Full Text Available Staphylococcus aureus requires branched-chain amino acids (BCAAs; isoleucine, leucine, valine for protein synthesis, branched-chain fatty acid synthesis, and environmental adaptation by responding to their availability via the global transcriptional regulator CodY. The importance of BCAAs for S. aureus physiology necessitates that it either synthesize them or scavenge them from the environment. Indeed S. aureus uses specialized transporters to scavenge BCAAs, however, its ability to synthesize them has remained conflicted by reports that it is auxotrophic for leucine and valine despite carrying an intact BCAA biosynthetic operon. In revisiting these findings, we have observed that S. aureus can engage in leucine and valine synthesis, but the level of BCAA synthesis is dependent on the BCAA it is deprived of, leading us to hypothesize that each BCAA differentially regulates the biosynthetic operon. Here we show that two mechanisms of transcriptional repression regulate the level of endogenous BCAA biosynthesis in response to specific BCAA availability. We identify a trans-acting mechanism involving isoleucine-dependent repression by the global transcriptional regulator CodY and a cis-acting leucine-responsive attenuator, uncovering how S. aureus regulates endogenous biosynthesis in response to exogenous BCAA availability. Moreover, given that isoleucine can dominate CodY-dependent regulation of BCAA biosynthesis, and that CodY is a global regulator of metabolism and virulence in S. aureus, we extend the importance of isoleucine availability for CodY-dependent regulation of other metabolic and virulence genes. These data resolve the previous conflicting observations regarding BCAA biosynthesis, and reveal the environmental signals that not only induce BCAA biosynthesis, but that could also have broader consequences on S. aureus environmental adaptation and virulence via CodY.

Acid digestion of combustible wastes: a status report

International Nuclear Information System (INIS)

Lerch, R.E.

1975-05-01

Work at the Hanford Engineering Development Laboratory on development of the acid digestion process for treating combustible wastes is discussed. Materials such as paper, rubber, and plastics are readily decomposed into a low volume, noncombustible residue. Engineering results using the Acid Digestion Test Unit are discussed. Tests to date generally duplicated earlier laboratory results with respect to waste processing rates, volume reduction, off-gas generation rates and volumes, acid consumption, and completeness of reaction. Demonstrated processing rates were as high as 5 kg/hr for short duration run periods. The tests indicated engineering feasibility of the acid digestion process and showed acid digestion to be a potentially attractive method for treating combustible nuclear wastes. Other areas discussed in the report are behavior of plutonium and americium during acid digestion, behavior of various construction materials, and safety. An integrated flowsheet for operation of an acid digestion unit is also presented. (U.S.)

Three-dimensional bioprinting of cell-laden constructs with polycaprolactone protective layers for using various thermoplastic polymers.

Science.gov (United States)

Kim, Byoung Soo; Jang, Jinah; Chae, Suhun; Gao, Ge; Kong, Jeong-Sik; Ahn, Minjun; Cho, Dong-Woo

2016-08-22

Three-dimensional (3D) cell-printed constructs have been recognized as promising biological substitutes for tissue/organ regeneration. They provide tailored physical properties and biological cues via multi-material printing process. In particular, hybrid bioprinting, enabling to use biodegradable synthetic polymers as framework, has been an attractive method to support weak hydrogels. The constructs with controlled architecture and high shape fidelity were fabricated through this method, depositing spatial arrangement of multi-cell types into microscale constructs. Among biodegradable synthetic polymers, polycaprolactone (PCL) has been commonly chosen in fabrication of cell-printed constructs because of its low melting temperature of 60 °C to be dispensed with extrusion-based bioprinting system. However, in addition to PCL, various synthetic polymers have been widely applied for tissue regeneration. These polymers have distinctive characteristics essential for tissue/organ regeneration. Nevertheless, it is difficult to use some polymers, such as poly (lactic-co-glycolic acid) (PLGA) and polylactic acid (PLA) with 3D bioprinting technology because of their high melting temperature to be dispensed, which can result in thermal damage to the cells in the printed constructs during the fabrication process. We present a novel bioprinting method to use various synthetic polymers in fabrication of cell-printed constructs. PCL was introduced as a protective layer to prevent thermal damage caused by high temperature of polymers during fabrication. Remarkable improvement in cellular activities in the printed constructs with PCL layers was observed compared with the construct without PCL. This bioprinting method can be applied to fabricate more tissue-like constructs through the use of various biomaterials.

Waste volume reduction by acid digestion

International Nuclear Information System (INIS)

Lerch, R.E.; Divine, J.R.

1975-06-01

Acid digestion is a process being developed at the Hanford Engineering Development Laboratory (HEDL) in Richland, Washington, to reduce the volume of alpha-contaminated combustible waste by converting it into a non-combustible residue. Typical waste materials such as polyvinylchloride (PVC), polyethylene, paper and other cellulosic materials, ion exchange resin, all types of rubber, etc., are digested in hot (230 0 C--270 0 C) concentrated sulfuric acid containing nitric acid oxidant to form inert residues generally having less than four percent of their original volume and less than twenty-five percent of their original mass. The process is currently being tested using non-radioactive waste in an Acid Digestion Test Unit (ADTU) with all glass equipment. Engineering tests to date have shown acid digestion to be a potentially attractive method for treating combustible waste materials. Based on results of the engineering tests, an acid digestion pilot unit capable of treating radioactive wastes is being designed and constructed. Design capacity of the pilot unit for radioactive waste will be 100 kg of waste per day. (U.S.)

Material compatibility evaluataion for DWPF nitric-glycolic acid - literature review

International Nuclear Information System (INIS)

Mickalonis, J.I; Skidmore, T.E.

2013-01-01

Glycolic acid is being evaluated as an alternative for formic and nitric acid in the DWPF flowsheet. Demonstration testing and modeling for this new flowsheet has shown that glycolic acid and glycolate has a potential to remain in certain streams generated during the production of the nuclear waste glass. A literature review was conducted to assess the impact of glycolic acid on the corrosion of the materials of construction for the DWPF facility as well as facilities downstream which may have residual glycolic acid and glycolates present. The literature data was limited to solutions containing principally glycolic acid. The reported corrosion rates and degradation characteristics have shown the following for the materials of construction: For C276 alloy, the primary material of construction for the CPC vessels, corrosion rates of either 2 or 20 mpy were reported up to a temperature of 93 deg C; For the austenitic stainless steels, 304L and 316L, variable rates were reported over a range of temperatures, varying from 2 mpy up to 200 mpy (at 100 deg C); For 690, G30, Allcorr, Ultimet and Stellite alloys no data were available; and, For relevant polymers where data are available, the data suggests that exposure to glycolic acid is not detrimental. The literature data had limited application to the DWPF process since only the storage and feed vessels, pumps and piping used to handle the glycolic acid are directly covered by the available data. These components are either 304L or 316L alloys for which the literature data is inconsistent (See Bullet 2 above). Corrosion rates in pure glycolic acid solutions also are not representative of the DWPF process streams. This stream is complex and contains aggressive species, i.e. chlorides, sulfates, mercury, as well as antifoaming agents which cumulatively have an unknown effect on the corrosion rates of the materials of construction. Therefore, testing is recommended to investigate any synergistic effects of the aggressive

L,L-diaminopimelate aminotransferase, a trans-kingdom enzyme shared by Chlamydia and plants for synthesis of diaminopimelate/lysine.

Science.gov (United States)

McCoy, Andrea J; Adams, Nancy E; Hudson, André O; Gilvarg, Charles; Leustek, Thomas; Maurelli, Anthony T

2006-11-21

The synthesis of meso-diaminopimelic acid (m-DAP) in bacteria is essential for both peptidoglycan and lysine biosynthesis. From genome sequencing data, it was unclear how bacteria of the Chlamydiales order would synthesize m-DAP in the absence of dapD, dapC, and dapE, which are missing from the genome. Here, we assessed the biochemical capacity of Chlamydia trachomatis serovar L2 to synthesize m-DAP. Expression of the chlamydial asd, dapB, and dapF genes in the respective Escherichia coli m-DAP auxotrophic mutants restored the mutants to DAP prototrophy. Screening of a C. trachomatis genomic library in an E. coli DeltadapD DAP auxotroph identified ct390 as encoding an enzyme that restored growth to the Escherichia coli mutant. ct390 also was able to complement an E. coli DeltadapD DeltadapE, but not a DeltadapD DeltadapF mutant, providing genetic evidence that it encodes an aminotransferase that may directly convert tetrahydrodipicolinate to L,L-diaminopimelic acid. This hypothesis was supported by in vitro kinetic analysis of the CT390 protein and the fact that similar properties were demonstrated for the Protochlamydia amoebophila homologue, PC0685. In vivo, the C. trachomatis m-DAP synthesis genes are expressed as early as 8 h after infection. An aminotransferase activity analogous to CT390 recently has been characterized in plants and cyanobacteria. This previously undescribed pathway for m-DAP synthesis supports an evolutionary relationship among the chlamydiae, cyanobacteria, and plants and strengthens the argument that chlamydiae synthesize a cell wall despite the inability of efforts to date to detect peptidoglycan in these organisms.

Novel (Phenylethynyl)pyrene-LNA Constructs for Fluorescence SNP Sensing in Polymorphic Nucleic Acid Targets

DEFF Research Database (Denmark)

Astakhova, Irina Kira; Samokhina, Evgeniya; Babu, B Ravindra

2012-01-01

We describe fluorescent oligonucleotide probes labeled with novel (phenylethynyl)pyrene dyes attached to locked nucleic acids. Furthermore, we prove the utility of these probes for the effective detection of single-nucleotide polymorphisms in natural nucleic acids. High-affinity hybridization......DNA and RNA gene fragments. Target sequences were obtained by analysis of 200 clinical samples from patients currently receiving anti-HIV/AIDS combination therapy at the Russian Federal AIDS Center. Using these fluorescent oligonucleotides, we were able to detect the target mutation despite all the challenges...

Polylactic acid organogel as versatile scaffolding technique

NARCIS (Netherlands)

Punet, Xavier; Levato, Riccardo; Bataille, Isabelle; Letourneur, Didier; Engel, Elisabeth; Mateos-Timoneda, Miguel A

2017-01-01

Tissue engineering requires scaffolding techniques based on non-toxic processes that permits the fabrication of constructs with tailored properties. Here, a two-step methodology based on the gelation and precipitation of the poly(lactic) acid/ethyl lactate organogel system is presented. With this

Effects and quantification of acid runoff from sulfide-bearing rock deposited during construction of Highway E18, Norway

Science.gov (United States)

Hindar, Atle; Nordstrom, D. Kirk

2015-01-01

The Highway E18 between the cities of Grimstad and Kristiansand, southern Norway, constructed in the period 2006–2009, cuts through sulfide-bearing rock. The geology of this area is dominated by slowly-weathering gneiss and granites, and oxidation of fresh rock surfaces can result in acidification of surface water. Sulfide-containing rock waste from excavations during construction work was therefore deposited in three waste rock deposits off-site. The deposits consist of 630,000–2,360,000 metric tons of waste rock material. Shell sand and limestone gravel were added in layers in adequate amounts to mitigate initial acid runoff in one of the deposits. The shell sand addition was not adequate in the two others. The pH in the effluents from these two was reduced from 4.9–6.5 to 4.0–4.6, and Al concentrations increased from below 0.4 mg/L to 10–20 mg/L. Stream concentrations of trace metals increased by a factor of 25–400, highest for Ni, and then in decreasing order for Co, Mn, Cd, Zn and Cu. Concentrations of As, Cr and Fe remained unchanged. Ratios of Co/Ni and Cd/Zn indicate that the metal sources for these pair of metals are sphalerite and pyrite, respectively. Based on surveys and established critical limits for Al, surface waters downstream became toxic to fish and invertebrates. The sulfur release rates were remarkably stable in the monitoring period at all three sites. Annual sulfur release was 0.1–0.4% of the total amount of sulfur in the deposit, indicating release periods of 250–800 years. Precipitates of Al-hydroxysulfates, well-known from mining sites, were found at the base of the deposits, in streams and also along the ocean shore-line. The effects of added neutralization agents in the deposits and in treatment areas downstream gradually decreased, as indicated by reduced stream pH over time. Active measures are needed to avoid harmful ecological effects in the future.

A fused selenium-containing protein with both GPx and SOD activities

International Nuclear Information System (INIS)

Yu, Huijun; Ge, Yan; Wang, Ying; Lin, Chi-Tsai; Li, Jing; Liu, Xiaoman; Zang, Tianzhu; Xu, Jiayun; Liu, Junqiu; Luo, Guimin; Shen, Jiacong

2007-01-01

As a safeguard against oxidative stress, the balance between the main antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) was believed to be more important than any single one, for example, dual-functional SOD/CAT enzyme has been proved to have better antioxidant ability than either single enzyme. By combining traditional fusion protein technology with amino acid auxotrophic expression system, we generated a bifunctional enzyme with both GPx and SOD activities. It displayed better antioxidant ability than GPx or SOD. Such dual-functional enzymes could facilitate further studies of the cooperation of GPx and SOD and generation of better therapeutic agents

PAMP-induced defense responses in potato require both salicylic acid and jasmonic acid.

Science.gov (United States)

Halim, Vincentius A; Altmann, Simone; Ellinger, Dorothea; Eschen-Lippold, Lennart; Miersch, Otto; Scheel, Dierk; Rosahl, Sabine

2009-01-01

To elucidate the molecular mechanisms underlying pathogen-associated molecular pattern (PAMP)-induced defense responses in potato (Solanum tuberosum), the role of the signaling compounds salicylic acid (SA) and jasmonic acid (JA) was analyzed. Pep-13, a PAMP from Phytophthora, induces the accumulation of SA, JA and hydrogen peroxide, as well as the activation of defense genes and hypersensitive-like cell death. We have previously shown that SA is required for Pep-13-induced defense responses. To assess the importance of JA, RNA interference constructs targeted at the JA biosynthetic genes, allene oxide cyclase and 12-oxophytodienoic acid reductase, were expressed in transgenic potato plants. In addition, expression of the F-box protein COI1 was reduced by RNA interference. Plants expressing the RNA interference constructs failed to accumulate the respective transcripts in response to wounding or Pep-13 treatment, neither did they contain significant amounts of JA after elicitation. In response to infiltration of Pep-13, the transgenic plants exhibited a highly reduced accumulation of reactive oxygen species as well as reduced hypersensitive cell death. The ability of the JA-deficient plants to accumulate SA suggests that SA accumulation is independent or upstream of JA accumulation. These data show that PAMP responses in potato require both SA and JA and that, in contrast to Arabidopsis, these compounds act in the same signal transduction pathway. Despite their inability to fully respond to PAMP treatment, the transgenic RNA interference plants are not altered in their basal defense against Phytophthora infestans.

Stereoselective synthesis of stable-isotope-labeled amino acids

Energy Technology Data Exchange (ETDEWEB)

Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

1994-12-01

For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

Stereoselective synthesis of stable-isotope-labeled amino acids

International Nuclear Information System (INIS)

Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.

1994-01-01

For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the α-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids

PPARd IS A LIPID SENSOR AND A REGULATOR OF FATTY ACID OXIDATION IN PANCREATIC β-CELLS

DEFF Research Database (Denmark)

Ravnskjær, Kim; Nielsen, Tina; Børgesen, Michael

to stimulate fatty acid oxidation when activated by agonists in myocytes, cardiomycytes and adipo-cytes. A role for PPARd as regulator of basal fatty acid catabolism and energy expenditure was therefore suggested. Here we show that PPARd is the most abundantly expressed PPAR subtype in both primary pancreatic...... islets and in the insulinoma cell line INS-1E. This is reflected at the functional level in activity assays using a PPRE-driven luciferase reporter construct. The fatty acids oleic, arachidonic and linolenic acid are able to acivate this construct synergistically with the synthetic RXR agonist LG100268....... Selective activation of PPARd in INS-1E cells with the PPARd agonist L165041 in the presence or absence of the RXRa agonist LG100268 induces luciferase activity 3- and 7-fold respectively and mimics the effect of the fatty acids. The same subset genes involved in fatty acid uptake and oxidation...

RevTrans: multiple alignment of coding DNA from aligned amino acid sequences

DEFF Research Database (Denmark)

Wernersson, Rasmus; Pedersen, Anders Gorm

2003-01-01

The simple fact that proteins are built from 20 amino acids while DNA only contains four different bases, means that the 'signal-to-noise ratio' in protein sequence alignments is much better than in alignments of DNA. Besides this information-theoretical advantage, protein alignments also benefit...... proteins. It is therefore preferable to align coding DNA at the amino acid level and it is for this purpose we have constructed the program RevTrans. RevTrans constructs a multiple DNA alignment by: (i) translating the DNA; (ii) aligning the resulting peptide sequences; and (iii) building a multiple DNA...

Health Profile of Construction Workers in Hong Kong.

Science.gov (United States)

Yi, Wen; Chan, Albert

2016-12-13

Construction is a manual, heavy, and complex sector concerning the most fatal accidents and high incidence of occupational illnesses and injuries resulting in days away from work. In Hong Kong, "Pilot Medical Examination Scheme for Construction Workers" was launched in 2014 to detect the health problems of their construction workforce. All registered workers under the Construction Workers Registration Board are eligible to join the scheme. The purpose of this paper is to assess the physical condition, physiological status, and musculoskeletal disorders of 942 construction workers in Hong Kong. This study adopted a two-phase design, which includes a basic medical examination to measure the workers' physiological parameters, such as blood pressure, resting heart rate, glucose, cholesterol, uric acid, liver function test, and renal function test; as well as a face-to-face interview following the medical examination to collect their demographic information and pain experience. Individual characteristics, including gender, age, obesity, alcohol drinking habit, and sleeping habit influenced the health condition of construction workers. Among the participants, 36.1% and 6.5% of them were overweight and obese, respectively. In addition, 43.0%, 38.4%, 16.2%, and 13.9% of the participants exceeded the thresholds of cholesterol, blood pressure, urea nitrogen, and uric urea, correspondingly. Moreover, 41.0% of the participants suffered musculoskeletal pain, where the most frequent painful parts occur in the lower back, shoulder, knees, leg, and neck. Through these findings, a series of important issues that need to be addressed is pointed out in terms of maintaining the physical well-being and reducing musculoskeletal disorders of construction workers. The finding may have implications for formulating proper intervention strategies for the sustainable development of Hong Kong's construction industry.

Management for Construction Materials and Control of Construction Waste in Construction Industry: A Review

OpenAIRE

A. A. Gulghane; Prof P. V. Khandve

2015-01-01

In recent treads a wide range of building materials is available for the construction of civil engineering structures. The total cost of materials may be up to 60% or more of the total cost incurred in construction project dependent upon the type of project. Effective construction materials management is a key to success for a construction project. Construction waste is another serious problem in construction industry. A large and various types of construction waste with different...

Acetohydroxyacid synthase FgIlv2 and FgIlv6 are involved in BCAA biosynthesis, mycelial and conidial morphogenesis, and full virulence in Fusarium graminearum.

Science.gov (United States)

Liu, Xin; Han, Qi; Xu, Jianhong; Wang, Jian; Shi, Jianrong

2015-11-10

In this study, we characterized FgIlv2 and FgIlv6, the catalytic and regulatory subunits of acetohydroxyacid synthase (AHAS) from the important wheat head scab fungus Fusarium graminearum. AHAS catalyzes the first common step in the parallel pathways toward branched-chain amino acids (BCAAs: isoleucine, leucine, valine) and is the inhibitory target of several commercialized herbicides. Both FgILV2 and FgILV6 deletion mutants were BCAA-auxotrophic and showed reduced aerial hyphal growth and red pigmentation when cultured on PDA plates. Conidial formation was completely blocked in the FgILV2 deletion mutant ΔFgIlv2-4 and significantly reduced in the FgILV6 deletion mutant ΔFgIlv6-12. The auxotrophs of ΔFgIlv2-4 and ΔFgIlv6-12 could be restored by exogenous addition of BCAAs but relied on the designated nitrogen source the medium contained. Deletion of FgILV2 or FgILV6 also leads to hypersensitivity to various cellular stresses and reduced deoxynivalenol production. ΔFgIlv2-4 lost virulence completely on flowering wheat heads, whereas ΔFgIlv6-12 could cause scab symptoms in the inoculated spikelet but lost its aggressiveness. Taken together, our study implies the potential value of antifungals targeting both FgIlv2 and FgIlv6 in F. graminearum.

Treatment and prevention systems for acid mine drainage and halogenated contaminants

Science.gov (United States)

Jin, Song [Fort Collins, CO; Fallgren, Paul H [Laramie, WY; Morris, Jeffrey M [Laramie, WY

2012-01-31

Embodiments include treatments for acid mine drainage generation sources (10 perhaps by injection of at least one substrate (11) and biologically constructing a protective biofilm (13) on acid mine drainage generation source materials (14). Further embodiments include treatments for degradation of contaminated water environments (17) with substrates such as returned milk and the like.

Acid digestion of combustible waste. Status report 2

International Nuclear Information System (INIS)

Allen, C.; Cowan, R.; Divine, J.

1978-10-01

The Radioactive Acid Digestion Test Unit (RADTU) has been constructed at Hanford to process combustible transuranic waste. Laboratory testing, pilot plant testing, engineering studies, and safety studies have been completed and incorporated in the system design. 44 figures, 7 tables

Acid-resistant organic coatings for the chemical industry: a review

DEFF Research Database (Denmark)

Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria Grundahl

2017-01-01

Industries that work with acidic chemicals in their processes need to make choices on how to properly contain the substances and avoid rapid corrosion of equipment. Certain organic coatings and linings can be used in such environments, either to protect vulnerable construction materials, or......, in combination with fiber reinforcement, to replace them. However, degradation mechanisms of organic coatings in acid service are not thoroughly understood and relevant quantitative investigations are scarce. This review describes the uses and limitations of acid-resistant coatings in the chemical industry...

Metabolically engineered cells for the production of polyunsaturated fatty acids

DEFF Research Database (Denmark)

2005-01-01

The present invention relates to the construction and engineering of cells, more particularly microorganisms for producing PUFAs with four or more double bonds from non-fatty acid substrates through heterologous expression of an oxygen requiring pathway. The invention especially involves...... improvement of the PUFA content in the host organism through fermentation optimization, e.g. decreasing the temperature and/or designing an optimal medium, or through improving the flux towards fatty acids by metabolic engineering, e.g. through over-expression of fatty acid synthases, over-expression of other...

A novel nanofiber Cur-loaded polylactic acid constructed by electrospinning

International Nuclear Information System (INIS)

Trang Mai, Thi Thu; Duong Le, Quang; Binh Nguyen, Hai; Hoa Phan, Thi Bich; Lam Tran, Dai; Nguyen, Xuan Phuc; Thuy Nguyen, Thi Thu; Seo Park, Jun; Ngoan Nguyen, Thi; Cham Ba, Thi

2012-01-01

Curcumin (Cur), extracted from the Curcuma longa L. plant, is well known for its anti-tumor, anti-oxidant, anti-inflammatory and anti-bacterial properties. Nanofiber mats of polylactic acid (PLA) loading Cur (5 wt%) were fabricated by electrospinning (e-spinning). Morphology and structure of the fibers were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The diameters of the obtained fibers varied from 200 to 300 nm. The release capacity of curcumin from curcumin-loaded PLA fibers was investigated in phosphate buffer saline (PBS) containing ethanol. After 24 h, 50% of the curcumin was released from curcumin-loaded PLA fibers. These results of electrospun (e-spun) fibers exhibit the potential for biomedical application

A novel nanofiber Cur-loaded polylactic acid constructed by electrospinning

Science.gov (United States)

Thu Trang Mai, Thi; Thu Thuy Nguyen, Thi; Duong Le, Quang; Ngoan Nguyen, Thi; Cham Ba, Thi; Binh Nguyen, Hai; Bich Hoa Phan, Thi; Tran, Dai Lam; Phuc Nguyen, Xuan; Park, Jun Seo

2012-06-01

Curcumin (Cur), extracted from the Curcuma longa L. plant, is well known for its anti-tumor, anti-oxidant, anti-inflammatory and anti-bacterial properties. Nanofiber mats of polylactic acid (PLA) loading Cur (5 wt%) were fabricated by electrospinning (e-spinning). Morphology and structure of the fibers were characterized by field emission scanning electron microscopy (FE-SEM) and Fourier transform infrared (FTIR) spectroscopy, respectively. The diameters of the obtained fibers varied from 200 to 300 nm. The release capacity of curcumin from curcumin-loaded PLA fibers was investigated in phosphate buffer saline (PBS) containing ethanol. After 24 h, 50% of the curcumin was released from curcumin-loaded PLA fibers. These results of electrospun (e-spun) fibers exhibit the potential for biomedical application.

Development and applications of Bacillus subtilis test systems for mutagens, involving DNA-repair deficiency and suppressible auxotrophic mutations

International Nuclear Information System (INIS)

Tanooka, H.

1977-01-01

A mutagen-tester of Bacillus subtilis was constructed and tested with known carcinogens. The parental strain HA101 of Okubo and Yanagida carrying suppressible nonsense mutations in his and met genes was transformed to carry an excision-repair deficiency mutation. The constructed strain TKJ5211 showed a 20-30-fold higher sensitivity for His + reversion than the parental strain when treated with UV and UV-mimetic chemicals but unchanged mutation frequency with X-rays and methyl methanesulfonate. The tester strain was used in a spot test of 30 selected chemicals and also for testing with liver homogenate activation. The results showed an almost equivalent but somewhat broader detection spectrum than the Salmonella typhimurium TA100 system. Another test method used a pair of B. subtilis strains differing in their DNA-repair capacity, i.e. the most UV-sensitive mutant HJ-15 and a wild-type strain, to detect repair-dependent DNA damage produced by chemicals. Spores could be used in either test

Recurrent Neural Network Model for Constructive Peptide Design.

Science.gov (United States)

Müller, Alex T; Hiss, Jan A; Schneider, Gisbert

2018-02-26

We present a generative long short-term memory (LSTM) recurrent neural network (RNN) for combinatorial de novo peptide design. RNN models capture patterns in sequential data and generate new data instances from the learned context. Amino acid sequences represent a suitable input for these machine-learning models. Generative models trained on peptide sequences could therefore facilitate the design of bespoke peptide libraries. We trained RNNs with LSTM units on pattern recognition of helical antimicrobial peptides and used the resulting model for de novo sequence generation. Of these sequences, 82% were predicted to be active antimicrobial peptides compared to 65% of randomly sampled sequences with the same amino acid distribution as the training set. The generated sequences also lie closer to the training data than manually designed amphipathic helices. The results of this study showcase the ability of LSTM RNNs to construct new amino acid sequences within the applicability domain of the model and motivate their prospective application to peptide and protein design without the need for the exhaustive enumeration of sequence libraries.

Efficient aspartic acid production by a psychrophile-based simple biocatalyst.

Science.gov (United States)

Tajima, Takahisa; Hamada, Mai; Nakashimada, Yutaka; Kato, Junichi

2015-10-01

We previously constructed a Psychrophile-based Simple bioCatalyst (PSCat) reaction system, in which psychrophilic metabolic enzymes are inactivated by heat treatment, and used it here to study the conversion of aspartic acid from fumaric acid mediated by the activity of aspartate ammonia-lyase (aspartase). In Escherichia coli, the biosynthesis of aspartic acid competes with that of L-malic acid produced from fumaric acid by fumarase. In this study, E. coli aspartase was expressed in psychrophilic Shewanella livingstonensis Ac10 heat treated at 50 °C for 15 min. The resultant PSCat could convert fumaric acid to aspartic acid without the formation of L-malic acid because of heat inactivation of psychrophilic fumarase activity. Furthermore, alginate-immobilized PSCat produced high yields of aspartic acid and could be re-used nine times. The results of our study suggest that PSCat can be applied in biotechnological production as a new approach to increase the yield of target compounds.

Chiral metal-organic frameworks bearing free carboxylic acids for organocatalyst encapsulation.

Science.gov (United States)

Liu, Yan; Xi, Xiaobing; Ye, Chengcheng; Gong, Tengfei; Yang, Zhiwei; Cui, Yong

2014-12-08

Two chiral carboxylic acid functionalized micro- and mesoporous metal-organic frameworks (MOFs) are constructed by the stepwise assembly of triple-stranded heptametallic helicates with six carboxylic acid groups. The mesoporous MOF with permanent porosity functions as a host for encapsulation of an enantiopure organic amine catalyst by combining carboxylic acids and chiral amines in situ through acid-base interactions. The organocatalyst-loaded framework is shown to be an efficient and recyclable heterogeneous catalyst for the asymmetric direct aldol reactions with significantly enhanced stereoselectivity in relative to the homogeneous organocatalyst. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nucleic acids and smart materials: advanced building blocks for logic systems.

Science.gov (United States)

Pu, Fang; Ren, Jinsong; Qu, Xiaogang

2014-09-03

Logic gates can convert input signals into a defined output signal, which is the fundamental basis of computing. Inspired by molecular switching from one state to another under an external stimulus, molecular logic gates are explored extensively and recognized as an alternative to traditional silicon-based computing. Among various building blocks of molecular logic gates, nucleic acid attracts special attention owing to its specific recognition abilities and structural features. Functional materials with unique physical and chemical properties offer significant advantages and are used in many fields. The integration of nucleic acids and functional materials is expected to bring about several new phenomena. In this Progress Report, recent progress in the construction of logic gates by combining the properties of a range of smart materials with nucleic acids is introduced. According to the structural characteristics and composition, functional materials are categorized into three classes: polymers, noble-metal nanomaterials, and inorganic nanomaterials. Furthermore, the unsolved problems and future challenges in the construction of logic gates are discussed. It is hoped that broader interests in introducing new smart materials into the field are inspired and tangible applications for these constructs are found. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Eight supramolecular assemblies constructed from bis(benzimidazole) and organic acids through strong classical hydrogen bonding and weak noncovalent interactions

Science.gov (United States)

Jin, Shouwen; Wang, Daqi

2014-05-01

Eight crystalline organic acid-base adducts derived from alkane bridged bis(N-benzimidazole) and organic acids (2,4,6-trinitrophenol, p-nitrobenzoic acid, m-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 5-sulfosalicylic acid and oxalic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. Of the eight compounds five are organic salts (1, 4, 6, 7 and 8) and the other three (2, 3, and 5) are cocrystals. In all of the adducts except 1 and 8, the ratio of the acid and the base is 2:1. All eight supramolecular assemblies involve extensive intermolecular classical hydrogen bonds as well as other noncovalent interactions. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, all the complexes displayed 3D framework structure. The results presented herein indicate that the strength and directionality of the classical N+-H⋯O-, O-H⋯O, and O-H⋯N hydrogen bonds (ionic or neutral) and other nonbonding associations between acids and ditopic benzimidazoles are sufficient to bring about the formation of cocrystals or organic salts.

Models construction for acetone-butanol-ethanol fermentations with acetate/butyrate consecutively feeding by graph theory.

Science.gov (United States)

Li, Zhigang; Shi, Zhongping; Li, Xin

2014-05-01

Several fermentations with consecutively feeding of acetate/butyrate were conducted in a 7 L fermentor and the results indicated that exogenous acetate/butyrate enhanced solvents productivities by 47.1% and 39.2% respectively, and changed butyrate/acetate ratios greatly. Then extracellular butyrate/acetate ratios were utilized for calculation of acids rates and the results revealed that acetate and butyrate formation pathways were almost blocked by corresponding acids feeding. In addition, models for acetate/butyrate feeding fermentations were constructed by graph theory based on calculation results and relevant reports. Solvents concentrations and butanol/acetone ratios of these fermentations were also calculated and the results of models calculation matched fermentation data accurately which demonstrated that models were constructed in a reasonable way. Copyright © 2014 Elsevier Ltd. All rights reserved.

KONSTRUKSI MUTAN PROTEIN FOSFATASE ptc2D Saccharomyces cerevisiae DENGAN METODE PENGGANTIAN GEN TARGET DENGAN POLYMERASE CHAIN REACTION (PCR

Directory of Open Access Journals (Sweden)

Hermansyah

2011-05-01

Full Text Available Yeast Saccharomyces cerevisiae is an excellent model to studi genes function of eukarotic cells such as study of gene encoding protein phosphatase PTC2. Novel phenotypic caused by mutated gene is an important step to study function of gene. In this study constructed mutant of PTC2 gene encoding protein phosphatase. Method that used in this construction was replacement of target gene (PTC2 with auxotroph marker Candida albicans HIS3 by Polymer Chain Reaction (PCR or called by PCR-mediated disruption. Mutant colonies which grew in selective medium SC without histidine were confirmed by PCR amplification. By using 1% Agarose gel electrophoresis the result showed that size of ptc2D::CgHIS3 transformant was 3.52 kb while wild type strain was 2.9 kb, indicated that ptc2D::CgHIS3 has integrated on chromosome V replacing PTC2 wild type.

Exploring the evolution of standard amino-acid alphabet: When genomics meets thermodynamics

International Nuclear Information System (INIS)

Zhang, Hong-Yu

2007-01-01

One of the most intriguing aspects of life is that despite the diversified apparent shapes, similar building blocks and infrastructures, such as standard amino acids and canonical genetic codes, are shared by most life on Earth. Thus, it is challenging to explore: why nature just selects these building blocks and strategies from numerous candidates to construct life? Was this deterministic or fortuitous? Thanks to the rapid progress in genomics, bioinformatics and synthetic biology, more and more basic principles underlying life design and construction were disclosed in the past decade. However, since the origin of early life is substantially a chemical process, to understand the enigma of life origin, chemists' efforts can not be neglected. In this paper, we focus on the evolution of standard amino-acid alphabet and indicate that chemistry, especially thermodynamics, is indeed critical to understanding the forming mechanisms of amino-acid alphabet. It is revealed that nature prefers low free energy and thus ubiquitous (cheap) small amino acids when beginning to build life, which is compatible with many recent findings from genomics and bioinformatics

Effect of gamma irradiation on genetic changes and myco toxin production by fungi isolated from corn grains

International Nuclear Information System (INIS)

Abou-Sereih, N.A.; Sahab, A.F.; El-Fiki, A.A.M.

1998-01-01

Three important fungi and the major myco toxins were isolated from different food and feed products. The effect of gamma irradiation on genome structures and its relation to the production of myco toxin were also investigated. The percentage of auxotrophic mutants and its relation to the production of myco toxin, when the strains were treated with gamma irradiation (o.1, 0.2, 0.3 and 0.4 kgy), were determined. In general, gamma radiation resulted in high percentage of mutation at 0.4 kgy and the production of mycotoxin decreased greatly or inhibited by 0.1, 0.2, 0.3 and 0.4 kgy due to change in the genetic construction of genes responsible for mycotoxin production

Designing anticancer peptides by constructive machine learning.

Science.gov (United States)

Grisoni, Francesca; Neuhaus, Claudia; Gabernet, Gisela; Müller, Alex; Hiss, Jan; Schneider, Gisbert

2018-04-21

Constructive machine learning enables the automated generation of novel chemical structures without the need for explicit molecular design rules. This study presents the experimental application of such a generative model to design membranolytic anticancer peptides (ACPs) de novo. A recurrent neural network with long short-term memory cells was trained on alpha-helical cationic amphipathic peptide sequences and then fine-tuned with 26 known ACPs. This optimized model was used to generate unique and novel amino acid sequences. Twelve of the peptides were synthesized and tested for their activity on MCF7 human breast adenocarcinoma cells and selectivity against human erythrocytes. Ten of these peptides were active against cancer cells. Six of the active peptides killed MCF7 cancer cells without affecting human erythrocytes with at least threefold selectivity. These results advocate constructive machine learning for the automated design of peptides with desired biological activities. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Monitoring sinew contraction during formation of tissue-engineered fibrin-based ligament constructs.

Science.gov (United States)

Paxton, Jennifer Z; Wudebwe, Uchena N G; Wang, Anqi; Woods, Daniel; Grover, Liam M

2012-08-01

The ability to study the gross morphological changes occurring during tissue formation is vital to producing tissue-engineered structures of clinically relevant dimensions in vitro. Here, we have used nondestructive methods of digital imaging and optical coherence tomography to monitor the early-stage formation and subsequent maturation of fibrin-based tissue-engineered ligament constructs. In addition, the effect of supplementation with essential promoters of collagen synthesis, ascorbic acid (AA) and proline (P), has been assessed. Contraction of the cell-seeded fibrin gel occurs unevenly within the first 5 days of culture around two fixed anchor points before forming a longitudinal ligament-like construct. AA+P supplementation accelerates gel contraction in the maturation phase of development, producing ligament-like constructs with a higher collagen content and distinct morphology to that of unsupplemented constructs. These studies highlight the importance of being able to control the methods of tissue formation and maturation in vitro to enable the production of tissue-engineered constructs with suitable replacement tissue characteristics for repair of clinical soft-tissue injuries.

A new method for the construction of a mutant library with a predictable occurrence rate using Poisson distribution.

Science.gov (United States)

Seong, Ki Moon; Park, Hweon; Kim, Seong Jung; Ha, Hyo Nam; Lee, Jae Yung; Kim, Joon

2007-06-01

A yeast transcriptional activator, Gcn4p, induces the expression of genes that are involved in amino acid and purine biosynthetic pathways under amino acid starvation. Gcn4p has an acidic activation domain in the central region and a bZIP domain in the C-terminus that is divided into the DNA-binding motif and dimerization leucine zipper motif. In order to identify amino acids in the DNA-binding motif of Gcn4p which are involved in transcriptional activation, we constructed mutant libraries in the DNA-binding motif through an innovative application of random mutagenesis. Mutant library made by oligonucleotides which were mutated randomly using the Poisson distribution showed that the actual mutation frequency was in good agreement with expected values. This method could save the time and effort to create a mutant library with a predictable mutation frequency. Based on the studies using the mutant libraries constructed by the new method, the specific residues of the DNA-binding domain in Gcn4p appear to be involved in the transcriptional activities on a conserved binding site.

Treatment of alpha-bearing combustible wastes using acid digestion

International Nuclear Information System (INIS)

Lerch, R.E.; Allen, C.R.; Blasewitz, A.G.

1978-01-01

Acid digestion has been developed at the Hanford Engineering Development Laboratory (HEDL) in Richland, Washington to reduce the volume of combustible nuclear waste materials, while converting them to an inert, noncombustible residue. A 100 kg/day test unit has recently been constructed to demonstrate the process using radioactively contaminated combustible wastes. The unit, called the Radioactive Acid Digestion Test Unit (RADTU) was completed in September 1977 and is currently undergoing cold shakedown tests. Hot operation is expected in May 1978. Features of RADTU include: storage and transfer station for incoming wastes, a feed preparation station, an extrusion feed mechanism for transfer of the waste to the acid digester, the acid digester a residue recovery system, and an off-gas treatment system

Treatment of alpha-bearing combustible wastes using acid digestion

International Nuclear Information System (INIS)

Lerch, R.E.; Allen, C.R.; Blasewitz, A.G.

1977-11-01

Acid digestion has been developed at the Hanford Engineering Development Laboratory (HEDL) in Richland, Washington to reduce the volume of combustible nuclear waste materials, while converting them to an inert, noncombustible residue. A 100 kg/day test unit has recently been constructed to demonstrate the process using radioactively contaminated combustible wastes. The unit, called the Radioactive Acid Digestion Test Unit (RADTU) was completed in September 1977 and is currently undergoing cold shakedown tests. Hot operation is expected in May 1978. Features of RADTU include: storage and transfer station for incoming wastes, a feed preparation station, an extrusion feed mechanism for transfer of the waste to the acid digester, the acid digester, a residue recovery system, and an off-gas treatment system

Construction management

CERN Document Server

Pellicer, Eugenio; Teixeira, José C; Moura, Helder P; Catalá, Joaquín

2014-01-01

The management of construction projects is a wide ranging and challenging discipline in an increasingly international industry, facing continual challenges and demands for improvements in safety, in quality and cost control, and in the avoidance of contractual disputes. Construction Management grew out of a Leonardo da Vinci project to develop a series of Common Learning Outcomes for European Managers in Construction. Financed by the European Union, the project aimed to develop a library of basic materials for developing construction management skills for use in a pan-European context. Focused exclusively on the management of the construction phase of a building project from the contractor's point of view, Construction Management covers the complete range of topics of which mastery is required by the construction management professional for the effective delivery of new construction projects. With the continued internationalisation of the construction industry, Construction Management will be required rea...

Design, construction, and characterization of high-performance membrane fusion devices with target-selectivity.

Science.gov (United States)

Kashiwada, Ayumi; Yamane, Iori; Tsuboi, Mana; Ando, Shun; Matsuda, Kiyomi

2012-01-31

Membrane fusion proteins such as the hemagglutinin glycoprotein have target recognition and fusion accelerative domains, where some synergistically working elements are essential for target-selective and highly effective native membrane fusion systems. In this work, novel membrane fusion devices bearing such domains were designed and constructed. We selected a phenylboronic acid derivative as a recognition domain for a sugar-like target and a transmembrane-peptide (Leu-Ala sequence) domain interacting with the target membrane, forming a stable hydrophobic α-helix and accelerating the fusion process. Artificial membrane fusion behavior between the synthetic devices in which pilot and target liposomes were incorporated was characterized by lipid-mixing and inner-leaflet lipid-mixing assays. Consequently, the devices bearing both the recognition and transmembrane domains brought about a remarkable increase in the initial rate for the membrane fusion compared with the devices containing the recognition domain alone. In addition, a weakly acidic pH-responsive device was also constructed by replacing three Leu residues in the transmembrane-peptide domain by Glu residues. The presence of Glu residues made the acidic pH-dependent hydrophobic α-helix formation possible as expected. The target-selective liposome-liposome fusion was accelerated in a weakly acidic pH range when the Glu-substituted device was incorporated in pilot liposomes. The use of this pH-responsive device seems to be a potential strategy for novel applications in a liposome-based delivery system. © 2011 American Chemical Society

Gene silencing of stearoyl-ACP desaturase enhances the stearic acid content in Chlamydomonas reinhardtii

NARCIS (Netherlands)

Jaeger, de L.; Springer, J.; Wolbert, E.J.H.; Martens, D.E.; Eggink, G.; Wijffels, R.H.

2017-01-01

In this study, stearoyl-ACP desaturase (SAD), the enzyme that converts stearic acid into oleic acid, is silenced by artificial microRNA in the green microalga Chlamydomonas reinhardtii. Two different constructs, which target different positions on the mRNA of stearoyl-ACP desaturase, were tested.

Synthesis and preliminary biological evaluations of (+)-isocampholenic acid-derived amides.

Science.gov (United States)

Grošelj, Uroš; Golobič, Amalija; Knez, Damijan; Hrast, Martina; Gobec, Stanislav; Ričko, Sebastijan; Svete, Jurij

2016-08-01

The synthesis of two novel (+)-isocampholenic acid-derived amines has been realized starting from commercially available (1S)-(+)-10-camphorsulfonic acid. The novel amines as well as (+)-isocampholenic acid have been used as building blocks in the construction of a library of amides using various aliphatic, aromatic, and amino acid-derived coupling partners using BPC and CDI as activating agents. Amide derivatives have been assayed against several enzymes that hold potential for the development of new drugs to battle bacterial infections and Alzheimer's disease. Compounds 20c and 20e showed promising selective sub-micromolar inhibition of human butyrylcholinesterase [Formula: see text] ([Formula: see text] values [Formula: see text] and [Formula: see text], respectively).

Construction of highly ordered polyaniline nanowires and their applications in DNA sensing.

Science.gov (United States)

Hao, Yuanqiang; Zhou, Binbin; Wang, Fangbin; Li, Juan; Deng, Liu; Liu, You-Nian

2014-02-15

A novel electrochemical active polyaniline (PANI) nanowire was fabricated and utilized for the construction of a highly sensitive and selective electrochemical sensor for hepatitis B virus gene. The uniform PANI nanowire was prepared by the enzymatic polymerization of aniline monomers on the amyloid-like nanofiber (AP nanowire), which was self-assembled from an aniline-attached nonapeptide, aniline-GGAAKLVFF (AP). The prepared PANI nanowires were characterized by electron microscopy, UV-vis absorption spectra, and cyclic voltammetry (CV). These ultra-thin nanowires displayed high electrochemical activity. Then the nucleic acid biosensor was constructed by modifying a glass carbon electrode with AP nanowires which were functionalized by a designed hair-pin loop DNA. Upon the presence of target nucleic acid and horseradish peroxidase (HRP) labeled oligonucleotide, the HRP will catalyze the polymerization of aniline monomers conjugated in AP nanowires, leading to the formation of PANI nanowires which can bring about a dramatical increase in the current response of the biosensor. The dynamic range of the sensor for hepatitis B virus gene is 2.0-800.0 fM with a low detection limit of 1.0 fM (3σ, n=10). The biosensor also displayed highly selectivity and stability. All these excellent performances of the developed biosensor indicate that this platform can be easily extended to the detection of other nucleic acids. © 2013 Elsevier B.V. All rights reserved.

Construction history and construction management

International Nuclear Information System (INIS)

Agh, S.

1999-01-01

The process of pre-design and design preparation of the Mochovce NPP as well as the construction history of the plant is highlighted, including the financing aspect and problems arising from changes in the technological and other conditions of start-up of the reactor units. The results of international audits performed to improve the level of nuclear safety and implementation of the measures suggested are also described. The milestones of the whole construction process and start-up process, the control and quality system, and the methods of control and management of the complex construction project are outlined. (author)

Constructing Aligned Assessments Using Automated Test Construction

Science.gov (United States)

Porter, Andrew; Polikoff, Morgan S.; Barghaus, Katherine M.; Yang, Rui

2013-01-01

We describe an innovative automated test construction algorithm for building aligned achievement tests. By incorporating the algorithm into the test construction process, along with other test construction procedures for building reliable and unbiased assessments, the result is much more valid tests than result from current test construction…

Construction of Bifunctional Co/H-ZSM-5 Catalysts for the Hydrodeoxygenation of Stearic Acid to Diesel-range Alkanes.

Science.gov (United States)

Wu, Guangjun; Zhang, Nan; Dai, Weili; Guan, Naijia; Li, Landong

2018-04-27

Bifunctional Co/H-ZSM-5 zeolites were prepared by surface organometallic chemistry grafting route, namely by the stoichiometric reaction between cobaltocene and the Brønsted acid sites in zeolites, and applied to the model reaction of stearic acid catalytic hydrodeoxygenation. Cobalt species existed in the form of isolated Co2+ ions at exchange positions after grafting, transformed to CoO species on the surface of zeolite and stabilized inside zeolite channels upon calcination in air, and finally reduced to metallic cobalt species of homogeneous clusters of ca. 1.5 nm by hydrogen. During this process, the Brønsted acid sites of H-ZSM-5 zeolites could be preserved with acid strength slightly reduced. The as-prepared bifunctional catalyst exhibited a ~16 times higher activity in stearic acid hydrodeoxygenation (2.11 gSAgcat-1h-1) than the reference catalyst (0.13 gSAgcat-1h-1) prepared by solid-state ion exchange, and a high C18/C17 ratio of ~24 was achieved as well. The remarkable hydrodeoxygenation performance of bifunctional Co/H-ZSM-5 could be explained from the effective synergy between the uniformed metallic cobalt clusters and the Brønsted acid sites in H-ZSM-5 zeolite. The simplified reaction network and kinetics of stearic acid hydrodeoxygenation catalyzed by the as-prepared bifunctional Co/H-ZSM-5 zeolites were also investigated. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antioxidative Categorization of Twenty Amino Acids Based on Experimental Evaluation.

Science.gov (United States)

Xu, Naijin; Chen, Guanqun; Liu, Hui

2017-11-27

In view of the great importance bestowed on amino acids as antioxidants in oxidation resistance, we attempted two common redox titration methods in this report, including micro-potassium permanganate titration and iodometric titration, to measure the antioxidative capacity of 20 amino acids, which are the construction units of proteins in living organisms. Based on the relative intensities of the antioxidative capacity, we further conducted a quantitative comparison and found out that the product of experimental values obtained from the two methods was proven to be a better indicator for evaluating the relative antioxidative capacity of amino acids. The experimental results were largely in accordance with structural analysis made on amino acids. On the whole, the 20 amino acids concerned could be divided into two categories according to their antioxidative capacity. Seven amino acids, including tryptophan, methionine, histidine, lysine, cysteine, arginine and tyrosine, were greater in total antioxidative capacity compared with the other 13 amino acids.

Construction Management of Electromechanical Engineering Project in Petrochemical Construction

Directory of Open Access Journals (Sweden)

Xi Tao

2017-03-01

Full Text Available Petrochemical industry as a basic industry, occupies a pivotal position in the national economy, with the continuous development of science and technology, electromechanical automation in the petrochemical industry has been widely used to save a lot of labor but also greatly improve the oil Chemical industry production efficiency. Therefore, in the construction of petrochemical industry, mechanical and electrical engineering as part of it. It plays a vital role. Petrochemical industry with the production of high temperature and high pressure and flammable and explosive gas, can strengthen the construction of mechanical and electrical engineering specialization and construction management of scientific, has become the relationship between the smooth development of mechanical and electrical engineering and engineering quality of the key, A direct impact on the petrochemical construction of the overall construction quality. To this end, it is necessary for the construction of petrochemical construction of electromechanical engineering construction management to promote the construction of mechanical and electrical engineering management level gradually increased. This article on the machine Electric engineering project construction management were discussed with a view to the petrochemical construction in the relevant aspects of the need to provide reference for reference.

Trienoic fatty acids and plant tolerance of temperature

Directory of Open Access Journals (Sweden)

Routaboul Jean-Marc

2002-01-01

Full Text Available The biophysical reactions of light harvesting and electron transport during photosynthesis take place in a uniquely constructed bilayer, the thylakoid. In all photosynthetic eukaryotes, the complement of atypical glycerolipid molecules that form the foundation of this membrane are characterised by sugar head-groups and a very high level of unsaturation in the fatty acids that occupy the central portion of the thylakoid bilayer. alpha-linolenic (18:3 or a combination of 18:3 and hexadecatrienoic (16:3 acids typically account for approximately two-thirds of all thylakoid membrane fatty acids and over 90% of the fatty acids of monogalactosyl diacylglycerol, the major thylakoid lipid [1, 2]. The occurrence of trienoic fatty acids as a major component of the thylakoid membrane is especially remarkable since these fatty acids form highly reactive targets for active oxygen species and free radicals, which are often the by-products of oxygenic photosynthesis. Photosynthesis is one of the most temperature-sensitive functions of plant [3, 4]. There remains a widespread belief that these trienoic fatty acids might have some crucial role in plants to be of such universal occurrence, especially in photosynthesis tolerance of temperature [5].

Bioprinting Cellularized Constructs Using a Tissue-specific Hydrogel Bioink

Science.gov (United States)

Skardal, Aleksander; Devarasetty, Mahesh; Kang, Hyun-Wook; Seol, Young-Joon; Forsythe, Steven D.; Bishop, Colin; Shupe, Thomas; Soker, Shay; Atala, Anthony

2016-01-01

Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as organ replacements for implantation in patients, and also, when created on a smaller size scale as model "organoids" that can be used in in vitro systems for drug and toxicology screening. Despite development of a wide variety of bioprinting devices, application of bioprinting technology can be limited by the availability of materials that both expedite bioprinting procedures and support cell viability and function by providing tissue-specific cues. Here we describe a versatile hyaluronic acid (HA) and gelatin-based hydrogel system comprised of a multi-crosslinker, 2-stage crosslinking protocol, which can provide tissue specific biochemical signals and mimic the mechanical properties of in vivo tissues. Biochemical factors are provided by incorporating tissue-derived extracellular matrix materials, which include potent growth factors. Tissue mechanical properties are controlled combinations of PEG-based crosslinkers with varying molecular weights, geometries (linear or multi-arm), and functional groups to yield extrudable bioinks and final construct shear stiffness values over a wide range (100 Pa to 20 kPa). Using these parameters, hydrogel bioinks were used to bioprint primary liver spheroids in a liver-specific bioink to create in vitro liver constructs with high cell viability and measurable functional albumin and urea output. This methodology provides a general framework that can be adapted for future customization of hydrogels for biofabrication of a wide range of tissue construct types. PMID:27166839

Bioprinting Cellularized Constructs Using a Tissue-specific Hydrogel Bioink.

Science.gov (United States)

Skardal, Aleksander; Devarasetty, Mahesh; Kang, Hyun-Wook; Seol, Young-Joon; Forsythe, Steven D; Bishop, Colin; Shupe, Thomas; Soker, Shay; Atala, Anthony

2016-04-21

Bioprinting has emerged as a versatile biofabrication approach for creating tissue engineered organ constructs. These constructs have potential use as organ replacements for implantation in patients, and also, when created on a smaller size scale as model "organoids" that can be used in in vitro systems for drug and toxicology screening. Despite development of a wide variety of bioprinting devices, application of bioprinting technology can be limited by the availability of materials that both expedite bioprinting procedures and support cell viability and function by providing tissue-specific cues. Here we describe a versatile hyaluronic acid (HA) and gelatin-based hydrogel system comprised of a multi-crosslinker, 2-stage crosslinking protocol, which can provide tissue specific biochemical signals and mimic the mechanical properties of in vivo tissues. Biochemical factors are provided by incorporating tissue-derived extracellular matrix materials, which include potent growth factors. Tissue mechanical properties are controlled combinations of PEG-based crosslinkers with varying molecular weights, geometries (linear or multi-arm), and functional groups to yield extrudable bioinks and final construct shear stiffness values over a wide range (100 Pa to 20 kPa). Using these parameters, hydrogel bioinks were used to bioprint primary liver spheroids in a liver-specific bioink to create in vitro liver constructs with high cell viability and measurable functional albumin and urea output. This methodology provides a general framework that can be adapted for future customization of hydrogels for biofabrication of a wide range of tissue construct types.

Research on construction quality and improvement of assembly construction

Science.gov (United States)

Cheng, Fei

2017-11-01

Based on the acceleration of the urbanization process and the improvement of the quality of life of our residents, the demand for building construction has been increasing. In this context, the construction industry in order to promote the construction efficiency, quality improvement, to meet the needs of the development of the times to strengthen the new technology, the use of new technologies. At present, China’s engineering construction units in the process of carrying out the project to strengthen the use of assembly-type construction technology, which thus achieved for the traditional construction work low-level, high time-consuming issues, and promote the steady improvement of production efficiency. Based on this, this paper focuses on the analysis of the connotation of the assembly structure and analyzes the quality problems in the construction process of the construction projects and puts forward the improvement measures to promote the improvement of the building quality and the construction of the building Construction speed. Based on this, this paper analyzes the structural system and design of prefabricated building.

Cell and protein compatible 3D bioprinting of mechanically strong constructs for bone repair

International Nuclear Information System (INIS)

Sawkins, M J; Mistry, P; Shakesheff, K M; Yang, J; Brown, B N; Bonassar, L J

2015-01-01

Rapid prototyping of bone tissue engineering constructs often utilizes elevated temperatures, organic solvents and/or UV light for materials processing. These harsh conditions may prevent the incorporation of cells and therapeutic proteins in the fabrication processes. Here we developed a method for using bioprinting to produce constructs from a thermoresponsive microparticulate material based on poly(lactic-co-glycolic acid) at ambient conditions. These constructs could be engineered with yield stresses of up to 1.22 MPa and Young’s moduli of up to 57.3 MPa which are within the range of properties of human cancellous bone. Further study showed that protein-releasing microspheres could be incorporated into the bioprinted constructs. The release of the model protein lysozyme from bioprinted constructs was sustainted for a period of 15 days and a high degree of protein activity could be measured up to day 9. This work suggests that bioprinting is a viable route to the production of mechanically strong constructs for bone repair under mild conditions which allow the inclusion of viable cells and active proteins. (paper)

Effects of phosphoenolpyruvate carboxylase desensitization on glutamic acid production in Corynebacterium glutamicum ATCC 13032.

Science.gov (United States)

Wada, Masaru; Sawada, Kazunori; Ogura, Kotaro; Shimono, Yuta; Hagiwara, Takuya; Sugimoto, Masakazu; Onuki, Akiko; Yokota, Atsushi

2016-02-01

Phosphoenolpyruvate carboxylase (PEPC) in Corynebacterium glutamicum ATCC13032, a glutamic-acid producing actinobacterium, is subject to feedback inhibition by metabolic intermediates such as aspartic acid and 2-oxoglutaric acid, which implies the importance of PEPC in replenishing oxaloacetic acid into the TCA cycle. Here, we investigated the effects of feedback-insensitive PEPC on glutamic acid production. A single amino-acid substitution in PEPC, D299N, was found to relieve the feedback control by aspartic acid, but not by 2-oxoglutaric acid. A simple mutant, strain R1, having the D299N substitution in PEPC was constructed from ATCC 13032 using the double-crossover chromosome replacement technique. Strain R1 produced glutamic acid at a concentration of 31.0 g/L from 100 g/L glucose in a jar fermentor culture under biotin-limited conditions, which was significantly higher than that of the parent, 26.0 g/L (1.19-fold), indicative of the positive effect of desensitized PEPC on glutamic acid production. Another mutant, strain DR1, having both desensitized PEPC and PYK-gene deleted mutations, was constructed in a similar manner using strain D1 with a PYK-gene deleted mutation as the parent. This mutation had been shown to enhance glutamic acid production in our previous study. Although marginal, strain D1 produced higher glutamic acid, 28.8 g/L, than ATCC13032 (1.11-fold). In contrast, glutamic acid production by strain DR-1 was elevated up to 36.9 g/L, which was 1.42-fold higher than ATCC13032 and significantly higher than the other three strains. The results showed a synergistic effect of these two mutations on glutamic acid production in C. glutamicum. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Experimental investigation of coating degradation during simultaneous acid and erosive particle exposure

DEFF Research Database (Denmark)

Møller, Victor Buhl; Dam-Johansen, Kim; Frankær, Sarah Maria

When used in industrial processes, such as stirred acid leaching in the mineral industry, thermoset coatings are exposed to a combination of aggressive chemicals and erosive particlewear. While each exposure condition has been studied separately, no research has been presented on the effects...... of a simultaneous exposure. To investigate this, a pilot-scale stirred acid leaching tank, containing erosive particles and acidic solutions, has been designed and constructed. Resin types considered are amine-cured novolac epoxy and vinyl ester. Transient coating degradation is mapped through visual inspection...

Two novel alkaline earth coordination polymers constructed from cinnamic acid and 1,10-phenanthroline: synthesis and structural and thermal properties.

Science.gov (United States)

Bendjellal, Nassima; Trifa, Chahrazed; Bouacida, Sofiane; Boudaren, Chaouki; Boudraa, Mhamed; Merazig, Hocine

2018-02-01

In coordination chemistry and crystal engineering, many factors influence the construction of coordination polymers and the final frameworks depend greatly on the organic ligands used. The diverse coordination modes of N-donor ligands have been employed to assemble metal-organic frameworks. Carboxylic acid ligands can deprotonate completely or partially when bonding to metal ions and can also act as donors or acceptors of hydrogen bonds; they are thus good candidates for the construction of supramolecular architectures. We synthesized under reflux or hydrothermal conditions two new alkaline earth(II) complexes, namely poly[(1,10-phenanthroline-κ 2 N,N')bis(μ-3-phenylprop-2-enoato-κ 3 O,O':O)calcium(II)], [Ca(C 10 H 7 O 2 ) 2 (C 10 H 8 N 2 )] n , (1), and poly[(1,10-phenanthroline-κ 2 N,N')(μ 3 -3-phenylprop-2-enoato-κ 4 O:O,O':O')(μ-3-phenylprop-2-enoato-κ 3 O,O':O)barium(II)], [Ba(C 10 H 7 O 2 ) 2 (C 10 H 8 N 2 )] n , (2), and characterized them by FT-IR and UV-Vis spectroscopies, thermogravimetric analysis (TGA) and single-crystal X-ray diffraction analysis, as well as by powder X-ray diffraction (PXRD) analysis. Complex (1) features a chain topology of type 2,4 C4, where the Ca atoms are connected by O and N atoms, forming a distorted bicapped trigonal prismatic geometry. Complex (2) displays chains of topology type 2,3,5 C4, where the Ba atom is nine-coordinated by seven O atoms of bridging/chelating carboxylate groups from two cinnamate ligands and by two N atoms from one phenanthroline ligand, forming a distorted tricapped prismatic arrangement. Weak C-H...O hydrogen bonds and π-π stacking interactions between phenanthroline ligands are responsible to the formation of a supramolecular three-dimensional network. The thermal decompositions of (1) and (2) in the temperature range 297-1173 K revealed that they both decompose in three steps and transform to the corresponding metal oxide.

Gene composer: database software for protein construct design, codon engineering, and gene synthesis.

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Lorimer, Don; Raymond, Amy; Walchli, John; Mixon, Mark; Barrow, Adrienne; Wallace, Ellen; Grice, Rena; Burgin, Alex; Stewart, Lance

2009-04-21

To improve efficiency in high throughput protein structure determination, we have developed a database software package, Gene Composer, which facilitates the information-rich design of protein constructs and their codon engineered synthetic gene sequences. With its modular workflow design and numerous graphical user interfaces, Gene Composer enables researchers to perform all common bio-informatics steps used in modern structure guided protein engineering and synthetic gene engineering. An interactive Alignment Viewer allows the researcher to simultaneously visualize sequence conservation in the context of known protein secondary structure, ligand contacts, water contacts, crystal contacts, B-factors, solvent accessible area, residue property type and several other useful property views. The Construct Design Module enables the facile design of novel protein constructs with altered N- and C-termini, internal insertions or deletions, point mutations, and desired affinity tags. The modifications can be combined and permuted into multiple protein constructs, and then virtually cloned in silico into defined expression vectors. The Gene Design Module uses a protein-to-gene algorithm that automates the back-translation of a protein amino acid sequence into a codon engineered nucleic acid gene sequence according to a selected codon usage table with minimal codon usage threshold, defined G:C% content, and desired sequence features achieved through synonymous codon selection that is optimized for the intended expression system. The gene-to-oligo algorithm of the Gene Design Module plans out all of the required overlapping oligonucleotides and mutagenic primers needed to synthesize the desired gene constructs by PCR, and for physically cloning them into selected vectors by the most popular subcloning strategies. We present a complete description of Gene Composer functionality, and an efficient PCR-based synthetic gene assembly procedure with mis-match specific endonuclease

Gene Composer: database software for protein construct design, codon engineering, and gene synthesis

Directory of Open Access Journals (Sweden)

Mixon Mark

2009-04-01

Full Text Available Abstract Background To improve efficiency in high throughput protein structure determination, we have developed a database software package, Gene Composer, which facilitates the information-rich design of protein constructs and their codon engineered synthetic gene sequences. With its modular workflow design and numerous graphical user interfaces, Gene Composer enables researchers to perform all common bio-informatics steps used in modern structure guided protein engineering and synthetic gene engineering. Results An interactive Alignment Viewer allows the researcher to simultaneously visualize sequence conservation in the context of known protein secondary structure, ligand contacts, water contacts, crystal contacts, B-factors, solvent accessible area, residue property type and several other useful property views. The Construct Design Module enables the facile design of novel protein constructs with altered N- and C-termini, internal insertions or deletions, point mutations, and desired affinity tags. The modifications can be combined and permuted into multiple protein constructs, and then virtually cloned in silico into defined expression vectors. The Gene Design Module uses a protein-to-gene algorithm that automates the back-translation of a protein amino acid sequence into a codon engineered nucleic acid gene sequence according to a selected codon usage table with minimal codon usage threshold, defined G:C% content, and desired sequence features achieved through synonymous codon selection that is optimized for the intended expression system. The gene-to-oligo algorithm of the Gene Design Module plans out all of the required overlapping oligonucleotides and mutagenic primers needed to synthesize the desired gene constructs by PCR, and for physically cloning them into selected vectors by the most popular subcloning strategies. Conclusion We present a complete description of Gene Composer functionality, and an efficient PCR-based synthetic gene

A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

International Nuclear Information System (INIS)

Wang, Jun; Bai, Chao; Hu, Huai-Ming; Yuan, Fei; Xue, Gang-Lin

2017-01-01

Eight Zn(II)-based coordination polymers, namely, [Zn 2 L 2 (2,2’-bipy)] n ·nH 2 O (1), [Zn 2 L 2 (phen)] n ·nH 2 O (2), [ZnL(phen)(H 2 O)] n (3), [Zn 3 L 3 (4,4’-bipy)] n (4), [Zn 2 L 2 (4,4’-bipy) 2 ] n [Zn 2 L 2 (H 2 O) 2 ] n ·2nH 2 O (5), [Zn 4 L 4 (bpp) 2 ] n (6), [ZnL(bbi) 0.5 ] n (7), [ZnL(bpz)] n (8) (H 2 L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu 2+ cations and CrO 4 2- anions, as well as detection ability for the different organic solvents and nitro explosives, in which indicates it could be

Use of expression constructs to dissect the functional domains of the CHS/beige protein: identification of multiple phenotypes.

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Ward, Diane McVey; Shiflett, Shelly L; Huynh, Dinh; Vaughn, Michael B; Prestwich, Glenn; Kaplan, Jerry

2003-06-01

The Chediak-Higashi Syndrome (CHS) and the orthologous murine disorder beige are characterized at the cellular level by the presence of giant lysosomes. The CHS1/Beige protein is a 3787 amino acid protein of unknown function. To determine functional domains of the CHS1/Beige protein, we generated truncated constructs of the gene/protein. These truncated proteins were transiently expressed in Cos-7 or HeLa cells and their effect on membrane trafficking was examined. Beige is apparently a cytosolic protein, as are most transiently expressed truncated Beige constructs. Expression of the Beige construct FM (amino acids 1-2037) in wild-type cells led to enlarged lysosomes. Similarly, expression of a 5.5-kb region (amino acids 2035-3787) of the carboxyl terminal of Beige (22B) also resulted in enlarged lysosomes. Expression of FM solely affected lysosome size, whereas expression of 22B led to alterations in lysosome size, changes in the Golgi and eventually cell death. The two constructs could be used to further dissect phenotypes resulting from loss of the Beige protein. CHS or beigej fibroblasts show an absence of nuclear staining using a monoclonal antibody directed against phosphatidylinositol 4,5 bisphosphate [PtdIns(4,5) P2]. Transformation of beige j fibroblasts with a YAC containing the full-length Beige gene resulted in the normalization of lysosome size and nuclear PtdIns(4,5)P2 staining. Expression of the carboxyl dominant negative construct 22B led to loss of nuclear PtdIns(4,5)P2 staining. Expression of the FM dominant negative clone did not alter nuclear PtdIns(4,5) P2 localization. These results suggest that the Beige protein interacts with at least two different partners and that the Beige protein affects cellular events, such as nuclear PtdIns(4,5)P2 localization, in addition to lysosome size.

The remarkable stability of chimeric, sialic acid-derived alpha/delta-peptides in human blood plasma.

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Saludes, Jonel P; Natarajan, Arutselvan; DeNardo, Sally J; Gervay-Hague, Jacquelyn

2010-05-01

Peptides are labile toward proteolytic enzymes, and structural modifications are often required to prolong their metabolic half-life and increase resistance. One modification is the incorporation of non-alpha-amino acids into the peptide to deter recognition by hydrolytic enzymes. We previously reported the synthesis of chimeric alpha/delta-peptides from glutamic acids (Glu) and the sialic acid derivative Neu2en. Conformational analyses revealed these constructs adopt secondary structures in water and may serve as conformational surrogates of polysialic acid. Polysialic acid is a tumor-associated polysaccharide and is correlated with cancer metastasis. Soluble polysialic acid is rapidly cleared from the blood limiting its potential for vaccine development. One motivation in developing structural surrogates of polysialic acid was to create constructs with increased bioavailability. Here, we report plasma stability profiles of Glu/Neu2en alpha/delta-peptides. DOTA was conjugated at the peptide N-termini by solid phase peptide synthesis, radiolabeled with (111)In, incubated in human blood plasma at 37 degrees C, and their degradation patterns monitored by cellulose acetate electrophoresis and radioactivity counting. Results indicate that these peptides exhibit a long half-life that is two- to three-orders of magnitude higher than natural alpha-peptides. These findings provide a viable platform for the synthesis of plasma stable, sialic acid-derived peptides that may find pharmaceutical application.

Crosslinked Aspartic Acids as Helix-Nucleating Templates.

Science.gov (United States)

Zhao, Hui; Liu, Qi-Song; Geng, Hao; Tian, Yuan; Cheng, Min; Jiang, Yan-Hong; Xie, Ming-Sheng; Niu, Xiao-Gang; Jiang, Fan; Zhang, Ya-Ou; Lao, Yuan-Zhi; Wu, Yun-Dong; Xu, Nai-Han; Li, Zi-Gang

2016-09-19

Described is a facile helix-nucleating template based on a tethered aspartic acid at the N-terminus [terminal aspartic acid (TD)]. The nucleating effect of the template is subtly influenced by the substituent at the end of the side-chain-end tether as indicated by circular dichroism, nuclear magnetic resonance, and molecular dynamics simulations. Unlike most nucleating strategies, the N-terminal amine is preserved, thus enabling further modification. Peptidomimetic estrogen receptor modulators (PERMs) constructed using this strategy show improved therapeutic properties. The current strategy can be regarded as a good complement to existing helix-stabilizing methods. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Potential and Benefits of Building Information Modeling (BIM During Pre-Construction, Construction and Post Construction Stage

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Aw Nien Wei

2017-11-01

Full Text Available The construction industry is the main economic support for all countries around the world in which continually adapting to meet competitive challenges around the global market. Nevertheless, the construction project is becoming much more complex and difficult to manage. This is because the construction project involves a large number of stakeholder, for example, the consultant companies, architects, engineers, building surveyors and quantity surveyors. The technology currently used in the construction industry is the AutoCAD (Automatic computeraided design. AutoCAD is a commercial software application for 2D and 3D computer-aided design (CAD and drafting develop by Autodesk. Generally, all the drawing design from Autocad will be exchanged among the stakeholder in the form of paper. Information exchanged among them mostly involves a lot of documents and drawings. This practice creates errors because of documents and drawings are mostly in a paper-based format that is not properly managed which results in miscommunication among them. Having wrong information in the construction process could hinder the productivity of projects because in a construction project information is one of the important construction materials. Building Information Modeling (BIM is one of the newly software in the architecture, engineering, and construction (AEC industries to ensure all parties receive the right information. BIM technology is also an intelligent model of a building constructed digitally in the way of 3D. The software will generate model containing the information needed to support the construction, fabrication, and procurement activities that needed to realize the building. This paper will discuss on potential and benefits of BIM during pre-construction stage, construction stage and during post construction stage

Construction of a Recyclable Genetic Marker and Serial Gene Deletions in the Human Pathogenic Mucorales Mucor circinelloides.

Science.gov (United States)

Garcia, Alexis; Adedoyin, Gloria; Heitman, Joseph; Lee, Soo Chan

2017-07-05

Mucor circinelloides is a human pathogen, biofuel producer, and model system that belongs to a basal fungal lineage; however, the genetics of this fungus are limited. In contrast to ascomycetes and basidiomycetes, basal fungal lineages have been understudied. This may be caused by a lack of attention given to these fungi, as well as limited tools for genetic analysis. Nonetheless, the importance of these fungi as pathogens and model systems has increased. M. circinelloides is one of a few genetically tractable organisms in the basal fungi, but it is far from a robust genetic system when compared to model fungi in the subkingdom Dikarya. One problem is the organism is resistant to drugs utilized to select for dominant markers in other fungal transformation systems. Thus, we developed a blaster recyclable marker system by using the pyrG gene (encoding an orotidine-5'-phosphate decarboxylase, ortholog of URA3 in Saccharomyces cerevisiae ). A 237-bp fragment downstream of the pyrG gene was tandemly incorporated into the upstream region of the gene, resulting in construction of a pyrG-dpl237 marker. To test the functionality of the pyrG-dpl237 marker, we disrupted the carRP gene that is involved in carotenoid synthesis in pyrG - mutant background. The resulting carRP :: pyrG-dpl237 mutants exhibit a white colony phenotype due to lack of carotene, whereas wild type displays yellowish colonies. The pyrG marker was then successfully excised, generating carRP-dpl237 on 5-FOA medium. The mutants became auxotrophic and required uridine for growth. We then disrupted the calcineurin B regulatory subunit cnbR gene in the carRP :: dpl237 strain, generating mutants with the alleles carRP :: dpl237 and cnbR :: pyrG These results demonstrate that the recyclable marker system is fully functional, and therefore the pyrG-dpl237 marker can be used for sequential gene deletions in M. circinelloides . Copyright © 2017 Garcia et al.

Construction of a Recyclable Genetic Marker and Serial Gene Deletions in the Human Pathogenic Mucorales Mucor circinelloides

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Alexis Garcia

2017-07-01

Full Text Available Mucor circinelloides is a human pathogen, biofuel producer, and model system that belongs to a basal fungal lineage; however, the genetics of this fungus are limited. In contrast to ascomycetes and basidiomycetes, basal fungal lineages have been understudied. This may be caused by a lack of attention given to these fungi, as well as limited tools for genetic analysis. Nonetheless, the importance of these fungi as pathogens and model systems has increased. M. circinelloides is one of a few genetically tractable organisms in the basal fungi, but it is far from a robust genetic system when compared to model fungi in the subkingdom Dikarya. One problem is the organism is resistant to drugs utilized to select for dominant markers in other fungal transformation systems. Thus, we developed a blaster recyclable marker system by using the pyrG gene (encoding an orotidine-5′-phosphate decarboxylase, ortholog of URA3 in Saccharomyces cerevisiae. A 237-bp fragment downstream of the pyrG gene was tandemly incorporated into the upstream region of the gene, resulting in construction of a pyrG-dpl237 marker. To test the functionality of the pyrG-dpl237 marker, we disrupted the carRP gene that is involved in carotenoid synthesis in pyrG− mutant background. The resulting carRP::pyrG-dpl237 mutants exhibit a white colony phenotype due to lack of carotene, whereas wild type displays yellowish colonies. The pyrG marker was then successfully excised, generating carRP-dpl237 on 5-FOA medium. The mutants became auxotrophic and required uridine for growth. We then disrupted the calcineurin B regulatory subunit cnbR gene in the carRP::dpl237 strain, generating mutants with the alleles carRP::dpl237 and cnbR::pyrG. These results demonstrate that the recyclable marker system is fully functional, and therefore the pyrG-dpl237 marker can be used for sequential gene deletions in M. circinelloides.

Optical Sensors for Detection of Amino Acids.

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Pettiwala, Aafrin M; Singh, Prabhat K

2017-11-06

Amino acids are crucially involved in a myriad of biological processes. Any aberrant changes in physiological level of amino acids often manifest in common metabolic disorders, serious neurological conditions and cardiovascular diseases. Thus, devising methods for detection of trace amounts of amino acids becomes highly elemental to their efficient clinical diagnosis. Recently, the domain of developing optical sensors for detection of amino acids has witnessed significant activity which is the focus of the current review article. We undertook a detailed search of the peer-reviewed literature that primarily deals with optical sensors for amino acids and focuses on the use of different type of materials as a sensing platform. Ninety-five papers have been included in the review, majority of which deals with optical sensors. We attempt to systematically classify these contributions based on applications of various chemical and biological scaffolds such as polymers, supramolecular assemblies, nanoparticles, DNA, heparin etc. for the sensing of amino acids. This review identifies that supramolecular assemblies and nanomaterial continue to be commonly used materials to devise sensors for amino acids followed by surfactant assemblies. The broad implications of amino acids in human health and diagnosis have stirred a lot of interest to develop optimized optical detection systems for amino acids in recent years, using different materials based on chemical and biological scaffolds. We have also attempted to highlight the merits and demerits of some of the noteworthy sensor systems to instigate further efforts for constructing amino acids sensor based on unconventional concepts. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Dynamic modeling of lactic acid fermentation metabolism with Lactococcus lactis.

Science.gov (United States)

Oh, Euhlim; Lu, Mingshou; Park, Changhun; Park, Changhun; Oh, Han Bin; Lee, Sang Yup; Lee, Jinwon

2011-02-01

A dynamic model of lactic acid fermentation using Lactococcus lactis was constructed, and a metabolic flux analysis (MFA) and metabolic control analysis (MCA) were performed to reveal an intensive metabolic understanding of lactic acid bacteria (LAB). The parameter estimation was conducted with COPASI software to construct a more accurate metabolic model. The experimental data used in the parameter estimation were obtained from an LC-MS/ MS analysis and time-course simulation study. The MFA results were a reasonable explanation of the experimental data. Through the parameter estimation, the metabolic system of lactic acid bacteria can be thoroughly understood through comparisons with the original parameters. The coefficients derived from the MCA indicated that the reaction rate of L-lactate dehydrogenase was activated by fructose 1,6-bisphosphate and pyruvate, and pyruvate appeared to be a stronger activator of L-lactate dehydrogenase than fructose 1,6-bisphosphate. Additionally, pyruvate acted as an inhibitor to pyruvate kinase and the phosphotransferase system. Glucose 6-phosphate and phosphoenolpyruvate showed activation effects on pyruvate kinase. Hexose transporter was the strongest effector on the flux through L-lactate dehydrogenase. The concentration control coefficient (CCC) showed similar results to the flux control coefficient (FCC).

Programming the Assembly of Unnatural Materials with Nucleic Acids

Science.gov (United States)

Mirkin, Chad

Nature directs the assembly of enormously complex and highly functional materials through an encoded class of biomolecules, nucleic acids. The establishment of a similarly programmable code for the construction of synthetic, unnatural materials would allow researchers to impart functionality by precisely positioning all material components. Although it is exceedingly difficult to control the complex interactions between atomic and molecular species in such a manner, interactions between nanoscale components can be directed through the ligands attached to their surface. Our group has shown that nucleic acids can be used as highly programmable surface ligands to control the spacing and symmetry of nanoparticle building blocks in structurally sophisticated and functional materials. These nucleic acids function as programmable ``bonds'' between nanoparticle ``atoms,'' analogous to a nanoscale genetic code for assembling materials. The sequence and length tunability of nucleic acid bonds has allowed us to define a powerful set of design rules for the construction of nanoparticle superlattices with more than 30 unique lattice symmetries, tunable defect structures and interparticle spacings, and several well-defined crystal habits. Further, the nature of the nucleic acid bond enables an additional level of structural control: temporal regulation of dynamic material response to external biomolecular and chemical stimuli. This control allows for the reversible transformation between thermodynamic states with different crystal symmetries, particle stoichiometries, thermal stabilities, and interparticle spacings on demand. Notably, our unique genetic approach affords functional nanoparticle architectures that, among many other applications, can be used to systematically explore and manipulate optoelectronic material properties, such as tunable interparticle plasmonic interactions, microstructure-directed energy emission, and coupled plasmonic and photonic modes.

Radioactive Acid Digestion Test Unit (RADTU), 1980

International Nuclear Information System (INIS)

Allen, C.R.

1980-01-01

The Radioactive Acid Digestion Test Unit (RADTU) was constructed at the Hanford Site, Richland, WA to demonstrate application of the acid digestion process for treating combustible transuranic wastes and scrap materials. Using its original tray digester vessel, RADTU recently completed a six-month campaign of processing potentially contaminated non-glovebox wastes from a Hanford plutonium facility. During the campaign, 2100 kg of largely cellulosic wastes were processed at an average sustained processing rate of 3 kg/h (limited by the acid-waste contact and the water boiloff rate from the acid feeds). On-line operating efficiency was nearly 50%, averaged over 12 hours/day, for five days/week. After shutdown, a new annular high-rate digester was installed for testing that demonstrated a sustained capacity of 8 kg/h to 10 kg/h with greatly improved contact between the digestion acid and the waste. The new unit began processing low-level waste from Hanford's z-Plant during June 1980. Plutonium levels in the waste processed will be increased gradually as operating experience has been gained. Processing recoverable scrap is expected to begin in the last quarter of CY 1980

The development of radioiodinated fatty acids for myocardial imaging

International Nuclear Information System (INIS)

Knapp, F.F. Jr.

1993-01-01

Since free fatty acids are the principal energy source for the normally oxygenated myocardium, the use of iodine-123-labeled fatty acid analogues is an attractive approach for myocardial imaging. Interest in the use of these substances results from divergent fatty acid metabolic pathways in ischemic (triglyceride storage) versus normoxic tissue (β-oxidative clearance), following flow-dependent delivery. Iodine-123-labeled fatty acids may offer a unique opportunity to identity myocardial viability using single photon emission tomography. The development of structurally-modified fatty acids became of interest because of the relatively long acquisition periods required for SPECT. The significant time required by early generation single- or dual-head SPECT systems for data acquisition requires minimal redistribution during the acquisition period to ensure accurate evaluation of the regional fatty acid distribution pattern after re-construction. Research has focussed on the evaluation of structural modifications which can be introduced into the fatty acid chain which would inhibit the subsequent β-oxidative catabolism which normally results in rapid myocardial clearance. Introduction of a methyl group in position-3 of the fatty acid carbon chain has been shown to significantly delay myocardial clearance and iodine-123-labeled 15-(p-iodophenyl)-3- R,S-methylpentadecanoic acid (BMIPP) is a new tracer based on this strategy

Genetic characterization of somatic recombination in Trichoderma pseudokoningii

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Barcellos Fernando Gomes

2003-01-01

Full Text Available Crossing experiments via hyphal anastomosis between two strains contrasting for auxotrophic markers of Trichoderma pseudokoningii were conducted to characterize the somatic recombination process in this specie. Four crossings were made and a total of 1052 colonies obtained from conidial suspensions of the heterokaryotic colonies were analyzed. Sixty-eight recombinant colonies, from four growing generations, were analyzed for the auxotrophic markers. Of the 68 colonies analyzed, 58 were stable after four generations and the remainders were unstable, reverting to one of the parentals. Most of the recombinant colonies were unstable through subculture and after four growing generations they showed the leu ino met markers (auxotrophic for leucin, inositol and metionin respectively. The unstable recombinant colonies showed irregular growing borders, sparse sporulation and frequent sector formation. The results suggest the occurrence of recombination mechanisms in the heterokaryon (somatic recombination, different from those described for the parasexual cycle or parameiosis. Therefore, we proposed the ocurrence of nuclei degradation from one parental (non prevalent parental in the heterokaryon and that the resulting chromosomal fragments may be incorporated into whole nuclei of the another parental (prevalent parental. However the parameiosis as originally described cannot be excluded.

Saturation mutagenesis in selected amino acids to shift Pseudomonas sp. acidic lipase Lip I.3 substrate specificity and activity.

Science.gov (United States)

Panizza, Paola; Cesarini, Silvia; Diaz, Pilar; Rodríguez Giordano, Sonia

2015-01-25

Several Pseudomonas sp. CR611 Lip I.3 mutants with overall increased activity and a shift towards longer chain substrates were constructed. Substitution of residues Y29 and W310 by smaller amino acids provided increased activity on C18-substrates. Residues G152 and S154, modified to study their influence on interfacial activation, displayed a five and eleven fold increased activity.

Folic Acid Production by Engineered Ashbya gossypii.

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Serrano-Amatriain, Cristina; Ledesma-Amaro, Rodrigo; López-Nicolás, Rubén; Ros, Gaspar; Jiménez, Alberto; Revuelta, José Luis

2016-11-01

Folic acid (vitamin B 9 ) is the common name of a number of chemically related compounds (folates), which play a central role as cofactors in one-carbon transfer reactions. Folates are involved in the biosynthesis and metabolism of nucleotides and amino acids, as well as supplying methyl groups to a broad range of substrates, such as hormones, DNA, proteins, and lipids, as part of the methyl cycle. Humans and animals cannot synthesize folic acid and, therefore, need them in the diet. Folic acid deficiency is an important and underestimated problem of micronutrient malnutrition affecting billions of people worldwide. Therefore, the addition of folic acid as food additive has become mandatory in many countries thus contributing to a growing demand of the vitamin. At present, folic acid is exclusively produced by chemical synthesis despite its associated environmental burdens. In this work, we have metabolically engineered the industrial fungus Ashbya gossypii in order to explore its potential as a natural producer of folic acid. Overexpression of FOL genes greatly enhanced the synthesis of folates and identified GTP cyclohydrolase I as the limiting step. Metabolic flux redirection from competing pathways also stimulated folic acid production. Finally, combinatorial engineering synergistically increased the production of different bioactive forms of the folic vitamin. Overall, strains were constructed which produce 146-fold (6595µg/L) more vitamin than the wild-type and by far represents the highest yield reported. Copyright © 2016 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

[Overexpression of four fatty acid synthase genes elevated the efficiency of long-chain polyunsaturated fatty acids biosynthesis in mammalian cells].

Science.gov (United States)

Zhu, Guiming; Saleh, Abdulmomen Ali Mohammed; Bahwal, Said Ahmed; Wang, Kunfu; Wang, Mingfu; Wang, Didi; Ge, Tangdong; Sun, Jie

2014-09-01

Three long-chain polyunsaturated fatty acids, docosahexaenoic acid (DHA, 22:6n-3), eicosapentaenoic acid (EPA, 20:5n-3) and arachidonic acid (ARA, 20:4n-6), are the most biologically active polyunsaturated fatty acids in the body. They are important in developing and maintaining the brain function, and in preventing and treating many diseases such as cardiovascular disease, inflammation and cancer. Although mammals can biosynthesize these long-chain polyunsaturated fatty acids, the efficiency is very low and dietary intake is needed to meet the requirement. In this study, a multiple-genes expression vector carrying mammalian A6/A5 fatty acid desaturases and multiple-genes expression vector carrying mammalian Δ6/Δ5 fatty acid desaturases and Δ6/Δ5 fatty acid elongases coding genes was used to transfect HEK293T cells, then the overexpression of the target genes was detected. GC-MS analysis shows that the biosynthesis efficiency and level of DHA, EPA and ARA were significantly increased in cells transfected with the multiple-genes expression vector. Particularly, DHA level in these cells was 2.5 times higher than in the control cells. This study indicates mammal possess a certain mechanism for suppression of high level of biosynthesis of long chain polyunsaturated fatty acids, and the overexpression of Δ6/Δ5 fatty acid desaturases and Δ6/Δ5 fatty acid elongases broke this suppression mechanism so that the level of DHA, EPA and ARA was significantly increased. This study also provides a basis for potential applications of this gene construct in transgenic animal to produce high level of these long-chain polyunsaturated fatty acid.

A process for uranium recovery in phosphoric acid

International Nuclear Information System (INIS)

Duarte Neto, J.

1984-01-01

Results are presented about studies carried out envisaging the development of a process for uranium recovery from phosphoric acid, produced from the concentrate obtained from phosphorus-uraniferous mineral from Itataia mines (CE, Brazil). This process uses a mixture of DEPA-TOPO as extractant and the extraction cycle involves the following stages: acid pre-treatment; adjustment of the oxidation potential so to ensure that all uranium is hexavalent; extraction of uranium from the acid; screening of the solvent to remove undesirable impurities; uranium re-extraction and precipitation; solvent recovery. A micro-pilot plant for continuous processing was built up. Data collected showed that uranium can be recovered with an yield greater than 99%, thus proving the feasibility of the process and encouraging the construction of a bigger scale plant. (Author) [pt

Effect of Pre-Construction on Construction Schedule and Client Loyalty

OpenAIRE

Jong Hoon Kim; Hyun-Soo Lee; Moonseo Park; Min Jeong; Inbeom Lee

2016-01-01

Pre-construction is essential in achieving the success of a construction project. Due to the early involvement of project participants in the construction phase, project managers are able to plan ahead and solve issues well in advance leading to the success of the project and the satisfaction of the client. This research utilizes quantitative data derived from construction management projects in order to identify the relationship between pre-construction, construction schedule, and client sat...

Sustainable Construction Risk Perceptions in the Kuwaiti Construction Industry

Directory of Open Access Journals (Sweden)

Dalya Ismael

2018-06-01

Full Text Available Sustainable construction is fundamentally different than traditional construction because it requires whole systems thinking, early collaboration across stakeholders, and core principles like reducing resource consumption, eliminating toxins, and applying life cycle costing. Construction professionals unfamiliar with this mindset and approach may perceive sustainable construction as risky. One of the global regions in need of more sustainable construction is the Middle Eastern and North African (MENA region. The MENA region is one of the fastest developing in the world. However, it is the slowest one in implementing sustainable construction practices. Kuwait, in particular, contributes 53% more carbon emissions per capita than the United States. To understand how the Kuwaiti construction industry perceives risks associated with more sustainable construction, a survey was developed with 52 risk elements in which 131 industry professionals responded. The results indicate that industry professionals perceive a lack of public awareness as the risk element with the highest probability of occurrence. The risk element with the highest possible negative impact on future projects is designers’ and contractors’ inexperience with sustainable construction. Other risks were found to include a high initial cost for materials and overall project costs. Educational interventions, changes in risk allocation, and behavioral science to reframe upfront costs as long-term savings are offered as possible solutions.

Impact of Branched-Chain Amino Acid Catabolism on Fatty Acid and Alkene Biosynthesis in Micrococcus luteus.

Science.gov (United States)

Surger, Maximilian J; Angelov, Angel; Stier, Philipp; Übelacker, Maria; Liebl, Wolfgang

2018-01-01

Micrococcus luteus naturally produces alkenes, unsaturated aliphatic hydrocarbons, and represents a promising host to produce hydrocarbons as constituents of biofuels and lubricants. In this work, we identify the genes for key enzymes of the branched-chain amino acid catabolism in M. luteus , whose first metabolic steps lead also to the formation of primer molecules for branched-chain fatty acid and olefin biosynthesis, and demonstrate how these genes can be used to manipulate the production of specific olefins in this organism. We constructed mutants of several gene candidates involved in the branched-chain amino acid metabolism or its regulation and investigated the resulting changes in the cellular fatty acid and olefin profiles by GC/MS. The gene cluster encoding the components of the branched-chain α-keto acid dehydrogenase (BCKD) complex was identified by deletion and promoter exchange mutagenesis. Overexpression of the BCKD gene cluster resulted in about threefold increased olefin production whereas deletion of the cluster led to a drastic reduction in branched-chain fatty acid content and a complete loss of olefin production. The specificities of the acyl-CoA dehydrogenases of the branched amino acid degradation pathways were deduced from the fatty acid and olefin profiles of the respective deletion mutant strains. In addition, growth experiments with branched amino acids as the only nitrogen source were carried out with the mutants in order to confirm our annotations. Both the deletion mutant of the BCKD complex, responsible for the further degradation of all three branched-chain amino acids, as well as the deletion mutant of the proposed isovaleryl-CoA dehydrogenase (specific for leucine degradation) were not able to grow on leucine in contrast to the parental strain. In conclusion, our experiments allow the unambigous assignment of specific functions to the genes for key enzymes of the branched-chain amino acid metabolism of M. luteus . We also show how

A series of coordination polymers constructed from R-isophthalic acid (R=-SO3H, -NO2, and -OH) and N-donor ligands: Syntheses, structures and fluorescence properties

Science.gov (United States)

Zhou, Yong-Hong; Zhou, Xu-Wan; Zhou, Su-Rong; Tian, Yu-Peng; Wu, Jie-Ying

2017-01-01

Six novel Zn(II), Cd(II), and Cu(II) mixed-ligand coordination complexes, namely, [Zn2Na(sip)2(bpp)3(Hbpp)(H2O)2]·8H2O (1), [Cd3(sip)2(nbi)6(H2O)2]·7H2O (2), [Zn(sip)(nbi)2(H2O)]·Hnbi·3H2O (3), [Cd(hip)(nbi)2(H2O)]·nbi·5H2O (4), [Cd2(nip)2(nbi)2(H2O)2]·DMF (5), and [Cu(nip)(nbi)(H2O)2]·H2O (6) (H3sip=5-sulfoisophthalic acid, H2hip=5-hydroxylisophthalic acid, H2nip=5-nitroisophthalic acid, bpp=1,3-bis(4-pyridyl)propane, and nbi=6-nitrobenzimidazole) have been synthesized hydrothermally by the self-assembly of R-isophthalic acid (R=-SO3H, -NO2, and -OH) and N-donor ligands. Single crystal X-ray analyses reveal that two Zn(II) ions and one Na(I) ion of complex 1 are linked through O atoms to generate a 1D linear chain. Then the 2D supramolecular architectures are constructed via intermolecular interactions. In complex 2, the Cd1 ions are connected by bridging carboxyl groups from sip3- anions to form 1D double chain, which are further connected by Cd2 ions to afford 2D layer structure. The adjacent 2D layers are further linked via hydrogen-bonding interactions to give 3D supramolecular network. Compounds 3-5 show 1D chain structures, which are assembled into 2D or 3D supramolecular frameworks via weak interactions. In compound 6, the Cu(II) ions are bridged by the nip2- ligands to form 48-membered ring, which is assembled into 1Dchain via the π-π stacking interaction. In addition, the thermal stabilities and fluorescence properties of these compounds have also been studied.

Construction Managers’ Perception of the Factors Affecting Sustainability in Construction Projects

OpenAIRE

Reza Taheriattar; Morvarid Farzanehrafat

2014-01-01

Sustainable construction is a comprehensive concept which requires long-term planning. Moreover, construction managers play a key role in leading, planning and scheduling of a construction project. As a result, sustainability of construction projects can be affected by construction managers’ decisions. In addition, for greater development of sustainable construction, affecting factors should firstly be notified. Therefore, it seems necessary to investigate construction managers’ perception of...

Nucleic acids for the rational design of reaction circuits.

Science.gov (United States)

Padirac, Adrien; Fujii, Teruo; Rondelez, Yannick

2013-08-01

Nucleic acid-based circuits are rationally designed in vitro assemblies that can perform complex preencoded programs. They can be used to mimic in silico computations. Recent works emphasized the modularity and robustness of these circuits, which allow their scaling-up. Another new development has led to dynamic, time-responsive systems that can display emergent behaviors like oscillations. These are closely related to biological architectures and provide an in vitro model of in vivo information processing. Nucleic acid circuits have already been used to handle various processes for technological or biotechnological purposes. Future applications of these chemical smart systems will benefit from the rapidly growing ability to design, construct, and model nucleic acid circuits of increasing size. Copyright © 2012 Elsevier Ltd. All rights reserved.

The Revival of a Failed Constructed Wetland Treating of a High Fe Load AMD

Science.gov (United States)

A.D. Karathanasis; C.D. Barton

1999-01-01

Acid mine drainage (AMD) from abandoned mines has significantly impaired water quality in eastern Kentucky. A small surface flow wetland constructed in 1989 to reduce AMD effects and subsequently failed after six months of operation was renovated by incorporating anoxic limestone drains (ALDs) and anaerobic subsurface drains promoting vertical flow through successive...

Application of Attenuated Total Reflectance-Fourier Transformed Infrared (ATR-FTIR) Spectroscopy To Determine the Chlorogenic Acid Isomer Profile and Antioxidant Capacity of Coffee Beans.

Science.gov (United States)

Liang, Ningjian; Lu, Xiaonan; Hu, Yaxi; Kitts, David D

2016-01-27

The chlorogenic acid isomer profile and antioxidant activity of both green and roasted coffee beans are reported herein using ATR-FTIR spectroscopy combined with chemometric analyses. High-performance liquid chromatography (HPLC) quantified different chlorogenic acid isomer contents for reference, whereas ORAC, ABTS, and DPPH were used to determine the antioxidant activity of the same coffee bean extracts. FTIR spectral data and reference data of 42 coffee bean samples were processed to build optimized PLSR models, and 18 samples were used for external validation of constructed PLSR models. In total, six PLSR models were constructed for six chlorogenic acid isomers to predict content, with three PLSR models constructed to forecast the free radical scavenging activities, obtained using different chemical assays. In conclusion, FTIR spectroscopy, coupled with PLSR, serves as a reliable, nondestructive, and rapid analytical method to quantify chlorogenic acids and to assess different free radical-scavenging capacities in coffee beans.

Construction labor productivity during nuclear power plant construction

International Nuclear Information System (INIS)

Murray, W.B.

1980-01-01

There is no single satisfactory way to measure productivity in the construction industry. The industry is too varied, too specialized and too dependent upon vast numbers of interrelations between trades, contractors, designers and owners. Hence, no universally reliable indices for measuring construction productivity has been developed. There are problems that are generic to all large union-built nuclear power plants. The actions of any one owner cannot rectify the shortcomings of the construction industry. The generic problems are being identified, and many national organizations are attempting to make the construction industry more productive by recommending various changes

Determination of uric acid in the presence of ascorbic acid with hexacyanoferrate lanthanum film modified electrode

International Nuclear Information System (INIS)

Wang Guangfeng; Meng Jian; Liu Hongying; Jiao Shoufeng; Zhang Wei; Chen Daolei; Fang Bin

2008-01-01

A glassy carbon electrode modified with LaHCF was constructed and was characterized by cyclic voltammetry (CV) and electrochemical impedance spectrum (EIS). The resulting LaHCF modified glassy carbon electrode had a good catalytic character on uric acid (UA) and was used to detect uric acid and ascorbic acid (AA) simultaneously. This modified electrode exhibits potent and persistent electron-mediating behavior followed by well-separated oxidation peaks towards UA and AA with activation overpotential. For UA and AA in mixture, one can well separate from the other with a potential large enough to allow the determination of one in presence of the other. The DPV peak currents obtained increased linearly on the UA in the range of 2.0 x 10 -7 to 1.0 x 10 -4 mol/L with the detection limit (signal-to-noise ratio was 3) for UA 1.0 x 10 -7 mol/L. The proposed method showed excellent selectivity and stability, and the determination of UA and AA simultaneously in urine was satisfactory

Efficient conversion of phenylpyruvic acid to phenyllactic acid by using whole cells of Bacillus coagulans SDM.

Science.gov (United States)

Zheng, Zhaojuan; Ma, Cuiqing; Gao, Chao; Li, Fengsong; Qin, Jiayang; Zhang, Haiwei; Wang, Kai; Xu, Ping

2011-04-20

Phenyllactic acid (PLA), a novel antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi, can be produced by many microorganisms, especially lactic acid bacteria. However, the concentration and productivity of PLA have been low in previous studies. The enzymes responsible for conversion of phenylpyruvic acid (PPA) into PLA are equivocal. A novel thermophilic strain, Bacillus coagulans SDM, was isolated for production of PLA. When the solubility and dissolution rate of PPA were enhanced at a high temperature, whole cells of B. coagulans SDM could effectively convert PPA into PLA at a high concentration (37.3 g l(-1)) and high productivity (2.3 g l(-1) h(-1)) under optimal conditions. Enzyme activity staining and kinetic studies identified NAD-dependent lactate dehydrogenases as the key enzymes that reduced PPA to PLA. Taking advantage of the thermophilic character of B. coagulans SDM, a high yield and productivity of PLA were obtained. The enzymes involved in PLA production were identified and characterized, which makes possible the rational design and construction of microorganisms suitable for PLA production with metabolic engineering.

Electrochemical construction

Science.gov (United States)

Einstein, Harry; Grimes, Patrick G.

1983-08-23

An electrochemical cell construction features a novel co-extruded plastic electrode in an interleaved construction with a novel integral separator-spacer. Also featured is a leak and impact resistant construction for preventing the spill of corrosive materials in the event of rupture.

A family of entangled coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and auxiliary N-donor ligands: Luminescent sensing

Energy Technology Data Exchange (ETDEWEB)

Wang, Jun [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); College of Chemistry and Environmental Engineering, Sichuan University of Science & Engineering, Zigong 643000 (China); Bai, Chao [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Hu, Huai-Ming, E-mail: ChemHu1@NWU.EDU.CN [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China); Yuan, Fei; Xue, Gang-Lin [Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, College of Chemistry and Materials Science, Northwest University, Xi' an 710127 (China)

2017-05-15

Eight Zn(II)-based coordination polymers, namely, [Zn{sub 2}L{sub 2}(2,2’-bipy)]{sub n}·nH{sub 2}O (1), [Zn{sub 2}L{sub 2}(phen)]{sub n}·nH{sub 2}O (2), [ZnL(phen)(H{sub 2}O)]{sub n} (3), [Zn{sub 3}L{sub 3}(4,4’-bipy)]{sub n} (4), [Zn{sub 2}L{sub 2}(4,4’-bipy){sub 2}]{sub n} [Zn{sub 2}L{sub 2}(H{sub 2}O){sub 2}]{sub n}·2nH{sub 2}O (5), [Zn{sub 4}L{sub 4}(bpp){sub 2}]{sub n} (6), [ZnL(bbi){sub 0.5}]{sub n} (7), [ZnL(bpz)]{sub n} (8) (H{sub 2}L=4,4’-([1,2-phenylenebis-(methylene)]bis(oxy))dibenzoic acid, 2,2’-bipy =2,2’-bipyridine, phen =1,10-phenanthroline, 4,4’-bpy=4,4’-bipyridine, bpp =1,3-bis(4-pyridyl)propane, bbi=1,4-bis(imidazol-1-yl)butane, bpz=3,3′,5,5′-tetramethyl-4,4′-bipyrazole), have been hydrothermally synthesized and structurally characterized. 1–8 display various coordination motifs with different entangled forms and conformations due to the effect of the assistant N-donor ligands. The photoluminescent properties of compounds 1–8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2+} cations and CrO{sub 4}{sup 2-} anions, as well as detection ability for the different organic solvents and nitro explosives. These results indicated that it could be utilized as a multi-responsive luminescent sensor. Furthermore, compound 3 also shows good chemical resistance to both acidity and alkalinity solutions with pH ranging from 2 to 13. Thus, multi-photofunctionality and fluorescent response to pH have been combined in the 3, which is the first example in the Zn-based hybrid materials. - Graphical abstract: Eight new Zn(II)-based coordination polymers constructed from a flexible V-shaped long bicarboxylic acid and different N-donor ligands have been hydrothermally synthesized through fixing the metal salts and the solvent systems. The photoluminescent properties of complexes 1−8 in solid state were studied. Interestingly, 3 exhibits highly efficient luminescent sensing for Cu{sup 2

Construction mathematics

CERN Document Server

Virdi, Surinder; Virdi, Narinder Kaur

2014-01-01

Construction Mathematics is an introductory level mathematics text, written specifically for students of construction and related disciplines. Learn by tackling exercises based on real-life construction maths. Examples include: costing calculations, labour costs, cost of materials and setting out of building components. Suitable for beginners and easy to follow throughout. Learn the essential basic theory along with the practical necessities. The second edition of this popular textbook is fully updated to match new curricula, and expanded to include even more learning exercises. End of chapter exercises cover a range of theoretical as well as practical problems commonly found in construction practice, and three detailed assignments based on practical tasks give students the opportunity to apply all the knowledge they have gained. Construction Mathematics addresses all the mathematical requirements of Level 2 construction NVQs from City & Guilds/CITB and Edexcel courses, including the BTEC First Diploma in...

Acid-base properties of the surface of the α-Al2O3 suspension

Science.gov (United States)

Ryazanov, M. A.; Dudkin, B. N.

2009-12-01

The distribution of the acid-base centers on the surface of α-Al2O3 suspension particles was studied by potentiometric titration, and the corresponding p K spectra were constructed. It was inferred that the double electric layer created by the supporting electrolyte substantially affected the screening of the acid-base centers on the particle surface of the suspension.

Validating MEDIQUAL Constructs

Science.gov (United States)

Lee, Sang-Gun; Min, Jae H.

In this paper, we validate MEDIQUAL constructs through the different media users in help desk service. In previous research, only two end-users' constructs were used: assurance and responsiveness. In this paper, we extend MEDIQUAL constructs to include reliability, empathy, assurance, tangibles, and responsiveness, which are based on the SERVQUAL theory. The results suggest that: 1) five MEDIQUAL constructs are validated through the factor analysis. That is, importance of the constructs have relatively high correlations between measures of the same construct using different methods and low correlations between measures of the constructs that are expected to differ; and 2) five MEDIQUAL constructs are statistically significant on media users' satisfaction in help desk service by regression analysis.

Integrated boiler, superheater, and decomposer for sulfuric acid decomposition

Science.gov (United States)

Moore, Robert [Edgewood, NM; Pickard, Paul S [Albuquerque, NM; Parma, Jr., Edward J.; Vernon, Milton E [Albuquerque, NM; Gelbard, Fred [Albuquerque, NM; Lenard, Roger X [Edgewood, NM

2010-01-12

A method and apparatus, constructed of ceramics and other corrosion resistant materials, for decomposing sulfuric acid into sulfur dioxide, oxygen and water using an integrated boiler, superheater, and decomposer unit comprising a bayonet-type, dual-tube, counter-flow heat exchanger with a catalytic insert and a central baffle to increase recuperation efficiency.

Phylogenetic analysis of Bacillus subtilis strains applicable to natto (fermented soybean) production.

Science.gov (United States)

Kubo, Yuji; Rooney, Alejandro P; Tsukakoshi, Yoshiki; Nakagawa, Rikio; Hasegawa, Hiromasa; Kimura, Keitarou

2011-09-01

Spore-forming Bacillus strains that produce extracellular poly-γ-glutamic acid were screened for their application to natto (fermented soybean food) fermentation. Among the 424 strains, including Bacillus subtilis and B. amyloliquefaciens, which we isolated from rice straw, 59 were capable of fermenting natto. Biotin auxotrophism was tightly linked to natto fermentation. A multilocus nucleotide sequence of six genes (rpoB, purH, gyrA, groEL, polC, and 16S rRNA) was used for phylogenetic analysis, and amplified fragment length polymorphism (AFLP) analysis was also conducted on the natto-fermenting strains. The ability to ferment natto was inferred from the two principal components of the AFLP banding pattern, and natto-fermenting strains formed a tight cluster within the B. subtilis subsp. subtilis group.

Mine-built ponds economically clear acid mine waters

Energy Technology Data Exchange (ETDEWEB)

Chironis, N P

1987-01-01

One of the by-products of surface mining is acid mine drainage. Traditional treatment of acid drainage is the addition of a base chemical such as sodium hydroxide, soda ash or lime to neutralize the water and allow metals, such as iron and manganese, to settle out. However researchers were intrigued by the idea of using home-made wetlands containing bogs of sphagnum moss to do the job naturally and more cheaply without the heavy application of chemicals. Such plants as cattails were found to be very effective. Aspects considered are: the wetlands affinity for acid water; the aid of algae and bacteria; building a wetland; and recommendations by the Bureau of Mines for constructing wetlands including flow capacity, pH goal, minerals removal, design criteria, plant materials, growing media, plant settling, nutrients, water level and flow control.

Assessing the sustainable construction of large construction companies in Malaysia

Science.gov (United States)

Adewale, Bamgbade Jibril; Mohammed, Kamaruddeen Ahmed; Nasrun, Mohd Nawi Mohd

2016-08-01

Considering the increasing concerns for the consideration of sustainability issues in construction project delivery within the construction industry, this paper assesses the extent of sustainable construction among Malaysian large contractors, in order to ascertain the level of the industry's impacts on both the environment and the society. Sustainable construction explains the construction industry's responsibility to efficiently utilise the finite resources while also reducing construction impacts on both humans and the environment throughout the phases of construction. This study used proportionate stratified random sampling to conduct a field study with a sample of 172 contractors out of the 708 administered questionnaires. Data were collected from large contractors in the eleven states of peninsular Malaysia. Using the five-level rating scale (which include: 1= Very Low; 2= Low; 3= Moderate; 4= High; 5= Very High) to describe the level of sustainable construction of Malaysian contractors based on previous studies, statistical analysis reveals that environmental, social and economic sustainability of Malaysian large contractors are high.

Construction and Self-Assembly of Single-Chain Polymer Nanoparticles via Coordination Association and Electrostatic Repulsion in Water.

Science.gov (United States)

Zhu, Zhengguang; Xu, Na; Yu, Qiuping; Guo, Lei; Cao, Hui; Lu, Xinhua; Cai, Yuanli

2015-08-01

Simultaneous coordination-association and electrostatic-repulsion interactions play critical roles in the construction and stabilization of enzymatic function metal centers in water media. These interactions are promising for construction and self-assembly of artificial aqueous polymer single-chain nanoparticles (SCNPs). Herein, the construction and self-assembly of dative-bonded aqueous SCNPs are reported via simultaneous coordination-association and electrostatic-repulsion interactions within single chains of histamine-based hydrophilic block copolymer. The electrostatic-repulsion interactions are tunable through adjusting the imidazolium/imidazole ratio in response to pH, and in situ Cu(II)-coordination leads to the intramolecular association and single-chain collapse in acidic water. SCNPs are stabilized by the electrostatic repulsion of dative-bonded block and steric shielding of nonionic water-soluble block, and have a huge specific surface area of function metal centers accessible to substrates in acidic water. Moreover, SCNPs can assemble into micelles, networks, and large particles programmably in response to the solution pH. These unique media-sensitive phase-transformation behaviors provide a general, facile, and versatile platform for the fabrication of enzyme-inspired smart aqueous catalysts. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Causes of Construction Delays in Qatar Construction Projects

OpenAIRE

Murat Gunduz; Mohanad H. A. AbuHassan

2016-01-01

Construction industry mainly focuses on the superstructure, infrastructure, and oil and gas industry. The development of infrastructure projects in developing countries attracted a lot of foreign construction contractors, consultants, suppliers and diversified workforce to interfere and to be evolved in such huge investment. Reducing worksite delays in such projects require knowledge and attention. Therefore, it is important to identify the influencing delay attributes affecting construction ...

Construction completion report

International Nuclear Information System (INIS)

1990-01-01

This Construction Completion Report documents the major construction projects at the Waste Isolation Pilot Plant (WIPP) site and related information on contracts, schedules, and other areas which affected construction. This report is not intended to be an exhaustive detailed analysis of construction, but is a general overview and summary of the WIPP construction. 10 refs., 29 figs

Interfacial assembly structures and nanotribological properties of saccharic acids.

Science.gov (United States)

Shi, Hongyu; Liu, Yuhong; Zeng, Qingdao; Yang, Yanlian; Wang, Chen; Lu, Xinchun

2017-01-04

Saccharides have been recognized as potential bio-lubricants because of their good hydration ability. However, the interfacial structures of saccharides and their derivatives are rarely studied and the molecular details of interaction mechanisms have not been well understood. In this paper, the supramolecular assembly structures of saccharic acids (including galactaric acid and lactobionic acid), mediated by hydrogen bonds O-HN and O-HO, were successfully constructed on a highly oriented pyrolytic graphite (HOPG) surface by introducing pyridine modulators and were explicitly revealed by using scanning tunneling microscopy (STM). Furthermore, friction forces were measured in the saccharic acid/pyridine co-assembled system by atomic force microscopy (AFM), revealing a larger value than a pristine saccharic acid system, which could be attributed to the stronger tip-assembled molecule interactions that lead to the higher potential energy barrier needed to overcome. The effort on saccharide-related supramolecular self-assembly and nanotribological behavior could provide a novel and promising pathway to explore the interaction mechanisms underlying friction and reveal the structure-property relationship at the molecular level.

Behavior of copper in acidic sulfate solution: Comparison with acidic chloride

Energy Technology Data Exchange (ETDEWEB)

Tromans, D.; Silva, J.C. [Univ. of British Columbia, Vancouver, British Columbia (Canada). Dept. of Metals and Materials Engineering

1997-03-01

The anodic polarization behavior of copper in a 0.1 M sulfuric acid (H{sub 2}SO{sub 4}) + 1 M sodium sulfate (Na{sub 2}SO{sub 4}) solution (pH = 2.0) was studied at room temperature under quiescent and stirred conditions. The behavior was compared with aqueous equilibria via construction of a potential-vs-pH (E-pH) diagram for the copper-sulfate-water (Cu-SO{sub 4}{sup 2}-H{sub 2}O) system. Interpretation of the behavior was aided by comparison with aqueous equilibria and polarization studies of copper in a 0.2 M hydrochloric acid (HCl) + 1 M sodium chloride (NaCl) solution(pH = 0.8). The initial anodic dissolution region in the acidic sulfate solution exhibited Tafel behavior with a slope consistent with formation of cupric ions (Cu{sup 2+}) whose rate of formation was charge-transfer controlled. At higher potentials, limiting current density (i{sub L}) behavior was observed under E-pH conditions that were consistent with formation of a film of copper sulfate pentahydrate (CuSO{sub 4} {degree} 5H{sub 2}O). Comparison of experimental i{sub L} values with those predicted by mass transport-controlled processes, using estimates of the diffusion layer thickness obtained from the mass transfer-influenced region of apparent Tafel behavior in the acidic chloride solution, were in sufficient agreement to indicate i{sub L} was controlled by the rate of dissolution of the CuSO{sub 4} {degree} 5H{sub 2}O film via transport of Cu{sup 2+} from the film-electrolyte interface into the bulk solution.

Recent advances in the electrochemical construction of heterocycles

Directory of Open Access Journals (Sweden)

Robert Francke

2014-12-01

Full Text Available Due to the fact that the major portion of pharmaceuticals and agrochemicals contains heterocyclic units and since the overall number of commercially used heterocyclic compounds is steadily growing, heterocyclic chemistry remains in the focus of the synthetic community. Enormous efforts have been made in the last decades in order to render the production of such compounds more selective and efficient. However, most of the conventional methods for the construction of heterocyclic cores still involve the use of strong acids or bases, the operation at elevated temperatures and/or the use of expensive catalysts and reagents. In this regard, electrosynthesis can provide a milder and more environmentally benign alternative. In fact, numerous examples for the electrochemical construction of heterocycles have been reported in recent years. These cases demonstrate that ring formation can be achieved efficiently under ambient conditions without the use of additional reagents. In order to account for the recent developments in this field, a selection of representative reactions is presented and discussed in this review.

Harties' two-man acid plant now fully on stream

International Nuclear Information System (INIS)

Anon.

1979-01-01

Hartebeesfontein gold mine is the most modern of its kind in South Africa. Only two men are required to operate this R12 million acid plant. The plant is capable of producing 140 000 t of sulphuric acid a year, and will meet its own uranium recovery process requirements as well as those of other uranium producers in the Klerksdorp and Stilfontein areas. In simplified form the process involves roasting pyrite to form sulphur dioxide. This is then cleaned, dried, heated and reacted over catalyst to produce sulphur tri-oxide which is combined with water to form sulphuric acid. Where the pyrite is gold-bearing, the resultant calcines from the roasting process are pumped to the mine's recovery plant where the residual gold is extracted. The main reason for the construction of the plant was to supply Hartebeesfontein and other uranium producers in the Klerksdorp and Stilfontein areas with sulphuric acid which is used in the uranium leaching process

Effects of fatty acid activation on photosynthetic production of fatty acid-based biofuels in Synechocystis sp. PCC6803

Directory of Open Access Journals (Sweden)

Gao Qianqian

2012-03-01

Full Text Available Abstract Background Direct conversion of solar energy and carbon dioxide to drop in fuel molecules in a single biological system can be achieved from fatty acid-based biofuels such as fatty alcohols and alkanes. These molecules have similar properties to fossil fuels but can be produced by photosynthetic cyanobacteria. Results Synechocystis sp. PCC6803 mutant strains containing either overexpression or deletion of the slr1609 gene, which encodes an acyl-ACP synthetase (AAS, have been constructed. The complete segregation and deletion in all mutant strains was confirmed by PCR analysis. Blocking fatty acid activation by deleting slr1609 gene in wild-type Synechocystis sp. PCC6803 led to a doubling of the amount of free fatty acids and a decrease of alkane production by up to 90 percent. Overexpression of slr1609 gene in the wild-type Synechocystis sp. PCC6803 had no effect on the production of either free fatty acids or alkanes. Overexpression or deletion of slr1609 gene in the Synechocystis sp. PCC6803 mutant strain with the capability of making fatty alcohols by genetically introducing fatty acyl-CoA reductase respectively enhanced or reduced fatty alcohol production by 60 percent. Conclusions Fatty acid activation functionalized by the slr1609 gene is metabolically crucial for biosynthesis of fatty acid derivatives in Synechocystis sp. PCC6803. It is necessary but not sufficient for efficient production of alkanes. Fatty alcohol production can be significantly improved by the overexpression of slr1609 gene.

Multifactorial Optimization of Contrast-Enhanced Nanofocus Computed Tomography for Quantitative Analysis of Neo-Tissue Formation in Tissue Engineering Constructs.

Directory of Open Access Journals (Sweden)

Maarten Sonnaert

Full Text Available To progress the fields of tissue engineering (TE and regenerative medicine, development of quantitative methods for non-invasive three dimensional characterization of engineered constructs (i.e. cells/tissue combined with scaffolds becomes essential. In this study, we have defined the most optimal staining conditions for contrast-enhanced nanofocus computed tomography for three dimensional visualization and quantitative analysis of in vitro engineered neo-tissue (i.e. extracellular matrix containing cells in perfusion bioreactor-developed Ti6Al4V constructs. A fractional factorial 'design of experiments' approach was used to elucidate the influence of the staining time and concentration of two contrast agents (Hexabrix and phosphotungstic acid and the neo-tissue volume on the image contrast and dataset quality. Additionally, the neo-tissue shrinkage that was induced by phosphotungstic acid staining was quantified to determine the operating window within which this contrast agent can be accurately applied. For Hexabrix the staining concentration was the main parameter influencing image contrast and dataset quality. Using phosphotungstic acid the staining concentration had a significant influence on the image contrast while both staining concentration and neo-tissue volume had an influence on the dataset quality. The use of high concentrations of phosphotungstic acid did however introduce significant shrinkage of the neo-tissue indicating that, despite sub-optimal image contrast, low concentrations of this staining agent should be used to enable quantitative analysis. To conclude, design of experiments allowed us to define the most optimal staining conditions for contrast-enhanced nanofocus computed tomography to be used as a routine screening tool of neo-tissue formation in Ti6Al4V constructs, transforming it into a robust three dimensional quality control methodology.

Sustainable construction: construction and demolition waste reconsidered.

Science.gov (United States)

del Río Merino, Mercedes; Izquierdo Gracia, Pilar; Weis Azevedo, Isabel Salto

2010-02-01

Construction activity in Europe has increased substantially in the past decade. Likewise, there has also been a commensurate rise in the generation of construction and demolition waste (C&DW). This, together with the fact that in many European countries the rate of recycling and reuse of C&DW is still quite low has engendered a serious environmental problem and a motivation to develop strategies and management plans to solve it. Due to its composition, there is a significant potential to reuse and/or recycle C&DW, and thereby, contribute to improving the sustainability of construction and development, but practical procedures are not yet widely known or practiced in the construction industry. This article (a) summarizes the different applications that are presently practiced to optimize the recovery and/or application of C&DW for reuse, and (b) proposes various measures and strategies to improve the processing of this waste. The authors suggest that to enhance environmental effectiveness, a conscious and comprehensive C&DW management plan should be implemented in each jurisdiction. More precisely, this study presents a holistic approach towards C&DW management, through which environmental benefits can be achieved through the application of new construction methods that can contribute to sustainable growth.

2-Aminopyrimidine-3,3,3-triphenylpropanoic acid (1/1).

Science.gov (United States)

Serafin, Mateusz F; Wheeler, Kraig A

2007-11-01

The title bimolecular compound, C(4)H(5)N(3).C(21)H(18)O(2), constructed from 2-aminopyrimidine and 3,3,3-triphenylpropanoic acid, forms a tetramolecular hydrogen-bonded motif via O-H...N, N-H...O and N-H...N contacts. This aggregate organizes to give crystal-packing motifs with hydrophilic and hydrophobic regions.

Barriers of lean construction implementation in the Moroccan construction industry

Science.gov (United States)

Bajjou, Mohamed Saad; Chafi, Anas

2018-04-01

Improving the production system performance has become a fundamental pillar that must be taken into consideration in the construction industry. Recent developments in the construction sector have led to renewed interest in new techniques of management. Lean Construction is a very effective approach that has gained a high popularity by its ability to eliminate waste and maximize the value for the customer. Although both developed and developing countries have gained large benefits by implementing Lean Construction approach, several experiences showed many barriers that are hindering its implementation especially in developing countries. This paper aims to assess the critical barriers to the successful implementation in the Moroccan construction industry. Based on a literature review, followed by an analysis of data collected from a questionnaire survey which targeted 330 practitioners in the Moroccan construction field, several barriers were identified as key barriers. The findings of this investigation revealed that there are significant barriers such as Lack of knowledge about Lean Construction concepts, Unskilled Human Resources, and insufficient financial resources.

Prefabrication in Building Construction: A Perspective of Pakistan Construction Industry

Directory of Open Access Journals (Sweden)

Nafees Ahmed Memon

2014-07-01

Full Text Available Construction industry is facing many problems in terms of construction waste, quality, environment, durability, safety and higher construction cost. Adoption of prefabrication is a possible solution to such problems. Accordingly, there is a need to study the prospects that would stimulate the appropriate discussion of the suitability of prefabrication and other construction methods for concrete buildings. Therefore, this study investigates the significance of advantages in adopting prefabrication along with hindrances through questionnaire survey. The data has been analyzed using RIW (Relative Importance Weight method as a MCDM approach. The results depict that main advantages of prefabrication are ?Shorter construction time? and ?Less construction site waste?. The top hindrances in adopting prefabrication as identified in this study are: ?Higher initial construction cost? and ?Inflexible for design changes?. Based on the survey results and apparent progress in the adoption of prefabrication around the world, it is concluded that the use of prefabrication is likely to increase in developing countries like Pakistan

Prefabrication in building construction: a perspective of pakistan construction industry

International Nuclear Information System (INIS)

Memon, N.A.; Memon, F.A.; Khehro, S.H.

2014-01-01

Construction industry is facing many problems in terms of construction waste, quality, environment, durability, safety and higher construction cost. Adoption of prefabrication is a possible solution to such problems. Accordingly, there is a need to study the prospects that would stimulate the appropriate discussion of the suitability of prefabrication and other construction methods for concrete buildings. Therefore, this study investigates the significance of advantages in adopting prefabrication along with hindrances through questionnaire survey. The data has been analyzed using RIW (Relative Importance Weight) method as a MCDM approach. The results depict that main advantages of prefabrication are Shorter construction time and Less construction site waste. The top hindrances in adopting prefabrication as identified in this study are: Higher initial construction cost and Inflexible for design changes. Based on the survey results and apparent progress in the adoption of prefabrication around the world, it is concluded that the use of prefabrication is likely to increase in developing countries like Pakistan. (author)

Experimental study of influence characteristics of flue gas fly ash on acid dew point

Science.gov (United States)

Song, Jinhui; Li, Jiahu; Wang, Shuai; Yuan, Hui; Ren, Zhongqiang

2017-12-01

The long-term operation experience of a large number of utility boilers shows that the measured value of acid dew point is generally lower than estimated value. This is because the influence of CaO and MgO on acid dew point in flue gas fly ash is not considered in the estimation formula of acid dew point. On the basis of previous studies, the experimental device for acid dew point measurement was designed and constructed, and the acid dew point under different smoke conditions was measured. The results show that the CaO and MgO in the flue gas fly ash have an obvious influence on the acid dew point, and the content of the fly ash is negatively correlated with the temperature of acid dew point At the same time, the concentration of H2SO4 in flue gas is different, and the acid dew point of flue gas is different, and positively correlated with the acid dew point.

Case inflection of construct state constructions in Dinka

DEFF Research Database (Denmark)

Andersen, Torben

2016-01-01

Dinka, a Nilo-Saharan language, is largely monosyllabic, but nevertheless it has a fairly rich morphology. Thus, most of its morphology is expressed by alternations in phonological material of the root. The inflectional categories of nouns manifested in this way include state and case in addition...... to number. The state category consists of an absolute state and two construct states. The case category includes a nominative, a genitive, an allative, and an essive/ablative. The present article shows how case inflection is manifested in complex noun phrases consisting of a noun in a construct state...... simultaneously carry state information and case information. Thus, the case inflection of construct state constructions in Dinka adds yet another layer of nonlinear morphology to nouns in this language....

Effects of highway construction on stream water quality and macroinvertebrate condition in a mid-atlantic highlands watershed, USA.

Science.gov (United States)

Chen, Yushun; Viadero, Roger C; Wei, Xinchao; Fortney, Ronald; Hedrick, Lara B; Welsh, Stuart A; Anderson, James T; Lin, Lian-Shin

2009-01-01

Refining best management practices (BMPs) for future highway construction depends on a comprehensive understanding of environmental impacts from current construction methods. Based on a before-after-control impact (BACI) experimental design, long-term stream monitoring (1997-2006) was conducted at upstream (as control, n = 3) and downstream (as impact, n = 6) sites in the Lost River watershed of the Mid-Atlantic Highlands region, West Virginia. Monitoring data were analyzed to assess impacts of during and after highway construction on 15 water quality parameters and macroinvertebrate condition using the West Virginia stream condition index (WVSCI). Principal components analysis (PCA) identified regional primary water quality variances, and paired t tests and time series analysis detected seven highway construction-impacted water quality parameters which were mainly associated with the second principal component. In particular, impacts on turbidity, total suspended solids, and total iron during construction, impacts on chloride and sulfate during and after construction, and impacts on acidity and nitrate after construction were observed at the downstream sites. The construction had statistically significant impacts on macroinvertebrate index scores (i.e., WVSCI) after construction, but did not change the overall good biological condition. Implementing BMPs that address those construction-impacted water quality parameters can be an effective mitigation strategy for future highway construction in this highlands region.

Biofabrication of tissue constructs by 3D bioprinting of cell-laden microcarriers

International Nuclear Information System (INIS)

Levato, Riccardo; Planell, Josep A; Engel, Elisabeth; Visser, Jetze; Malda, Jos; Mateos-Timoneda, Miguel A

2014-01-01

Bioprinting allows the fabrication of living constructs with custom-made architectures by spatially controlled deposition of multiple bioinks. This is important for the generation of tissue, such as osteochondral tissue, which displays a zonal composition in the cartilage domain supported by the underlying subchondral bone. Challenges in fabricating functional grafts of clinically relevant size include the incorporation of cues to guide specific cell differentiation and the generation of sufficient cells, which is hard to obtain with conventional cell culture techniques. A novel strategy to address these demands is to combine bioprinting with microcarrier technology. This technology allows for the extensive expansion of cells, while they form multi-cellular aggregates, and their phenotype can be controlled. In this work, living constructs were fabricated via bioprinting of cell-laden microcarriers. Mesenchymal stromal cell (MSC)-laden polylactic acid microcarriers, obtained via static culture or spinner flask expansion, were encapsulated in gelatin methacrylamide-gellan gum bioinks, and the printability of the composite material was studied. This bioprinting approach allowed for the fabrication of constructs with high cell concentration and viability. Microcarrier encapsulation improved the compressive modulus of the hydrogel constructs, facilitated cell adhesion, and supported osteogenic differentiation and bone matrix deposition by MSCs. Bilayered osteochondral models were fabricated using microcarrier-laden bioink for the bone compartment. These findings underscore the potential of this new microcarrier-based biofabrication approach for bone and osteochondral constructs. (paper)

Biofabrication of tissue constructs by 3D bioprinting of cell-laden microcarriers.

Science.gov (United States)

Levato, Riccardo; Visser, Jetze; Planell, Josep A; Engel, Elisabeth; Malda, Jos; Mateos-Timoneda, Miguel A

2014-09-01

Bioprinting allows the fabrication of living constructs with custom-made architectures by spatially controlled deposition of multiple bioinks. This is important for the generation of tissue, such as osteochondral tissue, which displays a zonal composition in the cartilage domain supported by the underlying subchondral bone. Challenges in fabricating functional grafts of clinically relevant size include the incorporation of cues to guide specific cell differentiation and the generation of sufficient cells, which is hard to obtain with conventional cell culture techniques. A novel strategy to address these demands is to combine bioprinting with microcarrier technology. This technology allows for the extensive expansion of cells, while they form multi-cellular aggregates, and their phenotype can be controlled. In this work, living constructs were fabricated via bioprinting of cell-laden microcarriers. Mesenchymal stromal cell (MSC)-laden polylactic acid microcarriers, obtained via static culture or spinner flask expansion, were encapsulated in gelatin methacrylamide-gellan gum bioinks, and the printability of the composite material was studied. This bioprinting approach allowed for the fabrication of constructs with high cell concentration and viability. Microcarrier encapsulation improved the compressive modulus of the hydrogel constructs, facilitated cell adhesion, and supported osteogenic differentiation and bone matrix deposition by MSCs. Bilayered osteochondral models were fabricated using microcarrier-laden bioink for the bone compartment. These findings underscore the potential of this new microcarrier-based biofabrication approach for bone and osteochondral constructs.

Lifestyle of the biotroph Agrobacterium tumefaciens in the ecological niche constructed on its host plant.

Science.gov (United States)

González-Mula, Almudena; Lang, Julien; Grandclément, Catherine; Naquin, Delphine; Ahmar, Mohammed; Soulère, Laurent; Queneau, Yves; Dessaux, Yves; Faure, Denis

2018-07-01

Agrobacterium tumefaciens constructs an ecological niche in its host plant by transferring the T-DNA from its Ti plasmid into the host genome and by diverting the host metabolism. We combined transcriptomics and genetics for understanding the A. tumefaciens lifestyle when it colonizes Arabidopsis thaliana tumors. Transcriptomics highlighted: a transition from a motile to sessile behavior that mobilizes some master regulators (Hfq, CtrA, DivK and PleD); a remodeling of some cell surface components (O-antigen, succinoglucan, curdlan, att genes, putative fasciclin) and functions associated with plant defense (Ef-Tu and flagellin pathogen-associated molecular pattern-response and glycerol-3-phosphate and nitric oxide signaling); and an exploitation of a wide variety of host resources, including opines, amino acids, sugars, organic acids, phosphate, phosphorylated compounds, and iron. In addition, construction of transgenic A. thaliana lines expressing a lactonase enzyme showed that Ti plasmid transfer could escape host-mediated quorum-quenching. Finally, construction of knock-out mutants in A. tumefaciens showed that expression of some At plasmid genes seemed more costly than the selective advantage they would have conferred in tumor colonization. We provide the first overview of A. tumefaciens lifestyle in a plant tumor and reveal novel signaling and trophic interplays for investigating host-pathogen interactions. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Usability Constructs

DEFF Research Database (Denmark)

Hertzum, Morten; Clemmesen, Torkil; Hornbæk, Kasper Anders Søren

2007-01-01

Whereas research on usability predominantly employs universal definitions of the aspects that comprise usability, people experience their use of information systems through personal constructs. Based on 48 repertory-grid interviews, this study investigates how such personal constructs are affected...... use of constructs traditionally associated with usability (e.g., easy-to-use, intuitive, and liked). Further analysis of the data is ongoing...

Efficiency evaluation for nanomaterials applied in well bottom zone treatment after completion of well construction

Directory of Open Access Journals (Sweden)

GREZINA Olga Anatolyevna,

2017-11-01

Full Text Available Efficient development of low production wells is not possible without the bottom zone treatment, both during the well development phase when its construction is completed and in the process of flow rate reduction during the operation phase. The efficiency evaluation for the new technology, including one in which nanomaterials are used, implies comparison of the actual level achieved after the new technology has been applied with the projected baseline level that might be achieved by the previously applied technique. The paper presents geological and statistical modeling of the bottom zone acid-implosion treatment performed with the hydrochloric acid solution in combination with the shock-wave effect characterized by cyclic recurrence and dynamic mode. The analyzed results have been achieved in the low permeable carbonate reservoir of a very complex geological structure in oil operating facility. The nature and the extent of geological-technological parameters influence on the acidimplosion treatment results were determined by the multiple regression method, and the most influential parameters were selected; recommendations for boreholes selection and technological parameters of treatment were made. Models to forecast flow rate and oil production growth, reduction of fractional oil content in the well production, the acid-implosion impact duration were elaborated. The models can be used to evaluate efficiency of bottom zone treatment technologies after completion of well construction with nanomaterials application.

hERG blocking potential of acids and zwitterions characterized by three thresholds for acidity, size and reactivity

DEFF Research Database (Denmark)

Nikolov, Nikolai Georgiev; Dybdahl, Marianne; Jonsdottir, Svava Osk

2014-01-01

with a concordance of 91% by a decision tree based on the rule. Two external validations were performed with sets of 35 and 48 observations, respectively, both showing concordances of 91%. In addition, a global QSAR model of hERG blocking was constructed based on a large diverse training set of 1374 chemicals...... covering all ionization classes, externally validated showing high predictivity and compared to the decision tree. The decision tree was found to be superior for the acids and zwitterionic ampholytes classes....

Identification of FadAB Complexes Involved in Fatty Acid β-Oxidation in Streptomyces coelicolor and Construction of a Triacylglycerol Overproducing strain

Directory of Open Access Journals (Sweden)

Simón Menendez-Bravo

2017-08-01

Full Text Available Oleaginous microorganisms represent possible platforms for the sustainable production of oleochemicals and biofuels due to their metabolic robustness and the possibility to be engineered. Streptomyces coelicolor is among the narrow group of prokaryotes capable of accumulating triacylglycerol (TAG as carbon and energy reserve. Although the pathways for TAG biosynthesis in this organism have been widely addressed, the set of genes required for their breakdown have remained elusive so far. Here, we identified and characterized three gene clusters involved in the β-oxidation of fatty acids (FA. The role of each of the three different S. coelicolor FadAB proteins in FA catabolism was confirmed by complementation of an Escherichia coliΔfadBA mutant strain deficient in β-oxidation. In S. coelicolor, the expression profile of the three gene clusters showed variation related with the stage of growth and the presence of FA in media. Flux balance analyses using a corrected version of the current S. coelicolor metabolic model containing detailed TAG biosynthesis reactions suggested the relevance of the identified fadAB genes in the accumulation of TAG. Thus, through the construction and analysis of fadAB knockout mutant strains, we obtained an S. coelicolor mutant that showed a 4.3-fold increase in the TAG content compared to the wild type strain grown under the same culture conditions.

Determination of ascorbic acid, dopamine, and uric acid by a novel electrochemical sensor based on pristine graphene

International Nuclear Information System (INIS)

Qi, Shaopeng; Zhao, Bo; Tang, Heqing; Jiang, Xiaoqing

2015-01-01

In this article, a novel electrochemical sensor based on pristine graphene (PG) is successfully constructed to detect ascorbic acid (AA), dopamine (DA), and uric acid (UA). The PG is obtained by liquid-phase exfoliation of graphite and characterized by transmission electron microscopy and X-ray photoelectron spectroscopy. The sensor based on PG prepared by this method to realize simultaneous determination of AA, DA, and UA is firstly reported. The linear detection ranges for AA, DA, and UA are 9.00–2314 μM, 5.00–710 μM, and 6.00–1330 μM, respectively, with detection limits of 6.45, 2.00, and 4.82 μM. This PG based sensor exhibits excellent performance for detection of AA, DA, and UA, which is much better than those electrochemical sensors based on chemical converted graphene

Efficient conversion of phenylpyruvic acid to phenyllactic acid by using whole cells of Bacillus coagulans SDM.

Directory of Open Access Journals (Sweden)

Zhaojuan Zheng

2011-04-01

Full Text Available Phenyllactic acid (PLA, a novel antimicrobial compound with broad and effective antimicrobial activity against both bacteria and fungi, can be produced by many microorganisms, especially lactic acid bacteria. However, the concentration and productivity of PLA have been low in previous studies. The enzymes responsible for conversion of phenylpyruvic acid (PPA into PLA are equivocal.A novel thermophilic strain, Bacillus coagulans SDM, was isolated for production of PLA. When the solubility and dissolution rate of PPA were enhanced at a high temperature, whole cells of B. coagulans SDM could effectively convert PPA into PLA at a high concentration (37.3 g l(-1 and high productivity (2.3 g l(-1 h(-1 under optimal conditions. Enzyme activity staining and kinetic studies identified NAD-dependent lactate dehydrogenases as the key enzymes that reduced PPA to PLA.Taking advantage of the thermophilic character of B. coagulans SDM, a high yield and productivity of PLA were obtained. The enzymes involved in PLA production were identified and characterized, which makes possible the rational design and construction of microorganisms suitable for PLA production with metabolic engineering.

Phosphoric acid fuel cell R and D activities at KACST

International Nuclear Information System (INIS)

Ghouse, M.; Aba-Oud, H.; Ba-Junaid, M.; Al-Garni, M.; Quadri, M.I.

1993-01-01

The PAFC (Phosphoric Acid Fuel Cell) activities are directed towards the development of components of single cell and experimental stacks at KACST. The main aim of the present task is to design and construct a 1 kW PAFC Stack and demonstrate it by integrating with an electrolyser using a DC current generated by a photovoltaic power source. This paper describes the preparation of porous teflon bonded gas diffusion carbon electrodes and their evaluation as single phosphoric acid fuel cells using hydrogen as a fuel and oxygen/air as an oxidant. 6 figs., 2 tabs., 15 refs

Leadership Quality for Malaysia Construction Leader to Steer a Success Construction Project

Directory of Open Access Journals (Sweden)

Ngah Nasaruddin Nur Ain

2016-01-01

Full Text Available Issues that dominate the construction industry for the long time such as time overrun, cost overrun, quality of construction and also safety during the construction process are difficult to resolve because of several factors involved which amongst them are leadership quality in the industry. Solving these issues can make the industry more sustainable in nature. This paper presents the need of leadership quality among construction parties involved to steer a construction project successfully. Literature work found that 11 leadership qualities to ensure construction project success. From the frequency analysis, five most dominant leadership qualities are team building, communication skill, visioning, planning & strategy skill, and decision making. Beside the literature, this study also seeks an opinion from a senior leader of a successful construction company regarding the need of these qualities amongst parties to resolve the construction issues. The results from an interview session indicate that he fully agreed with the need of all the qualities in the construction industry. This shows that there is a strong relationship between solving the issues with the leadership quality in ensuring construction project success. These qualities should be further investigated to acquire a better representation of leadership quality in resolving construction issues for Malaysia construction industry.

Acid-digestion treatment of plutonium-containing waste

International Nuclear Information System (INIS)

Wieczorek, H.; Kemmler, G.; Krause, H.

1981-01-01

The Radioactive Acid-Digestion Test Unit (RADTU) has been constructed at Hanford to demonstrate the application of the acid-digestion process for treating combustible transuranic wastes and scrap materials. The RADTU, with its original tray digestion vessel, has recently completed a six-month campaign processing potentially contaminated non-glovebox wastes from a Hanford plutonium facility. During this campaign, it processed 2100 kg largely cellulosic wastes at an average sustained processing rate of 3 kg/h as limited by the acid-waste contact and the water boil-off rate from the acid feeds. The on-line operating efficiency was nearly 50% on a twelve-hour day, five-day week basis. Following this campaign, a new annular high-rate digester has been installed for testing. In preliminary tests with simulated wastes, the new digester demonstrated a sustained capacity of 10 kg/h with greatly improved intimacy of contact between the digestion acid and the waste. The new design also doubles the heat-transfer surface, which is expected to provide at least twice the water boil-off rate of the previous tray digester design. Following shakedown testing with simulated and low-level wastes, the new unit will be used to process combustible plutonium scrap and waste from Hanford plutonium facilities for the purposes of volume reduction, plutonium recovery, and stabilization of the final waste form. (author)

Towards green construction

International Nuclear Information System (INIS)

Bajracharya, Bijaya B.; Shrestha, Prasanna M.

2000-01-01

Sustainability is the key to any development works. In the operation phase, hydro power is the most sustainable form of energy. However construction activities for the same power station are usually far from being green. The popular myth is that construction activity converts green into grey. Despite this popular myth, construction of a hydro power project in Nepal has made the project area greener than earlier during the construction phase itself. Choice of construction technology, appropriate level of environmental impact assessment, monitoring of environmental parameters along side the construction progress followed by mitigation at the right time; launching community development programmes side by side, having environmental specification in contractual documents and self-reliance to fulfill environmental obligations by contractors itself are the key factors in the environmental management within the construction activities. The main conclusions in the paper is the need to change the way to think about the project constraints

ConStruct: Improved construction of RNA consensus structures

Directory of Open Access Journals (Sweden)

Steger Gerhard

2008-04-01

Full Text Available Abstract Background Aligning homologous non-coding RNAs (ncRNAs correctly in terms of sequence and structure is an unresolved problem, due to both mathematical complexity and imperfect scoring functions. High quality alignments, however, are a prerequisite for most consensus structure prediction approaches, homology searches, and tools for phylogeny inference. Automatically created ncRNA alignments often need manual corrections, yet this manual refinement is tedious and error-prone. Results We present an extended version of CONSTRUCT, a semi-automatic, graphical tool suitable for creating RNA alignments correct in terms of both consensus sequence and consensus structure. To this purpose CONSTRUCT combines sequence alignment, thermodynamic data and various measures of covariation. One important feature is that the user is guided during the alignment correction step by a consensus dotplot, which displays all thermodynamically optimal base pairs and the corresponding covariation. Once the initial alignment is corrected, optimal and suboptimal secondary structures as well as tertiary interaction can be predicted. We demonstrate CONSTRUCT's ability to guide the user in correcting an initial alignment, and show an example for optimal secondary consensus structure prediction on very hard to align SECIS elements. Moreover we use CONSTRUCT to predict tertiary interactions from sequences of the internal ribosome entry site of CrP-like viruses. In addition we show that alignments specifically designed for benchmarking can be easily be optimized using CONSTRUCT, although they share very little sequence identity. Conclusion CONSTRUCT's graphical interface allows for an easy alignment correction based on and guided by predicted and known structural constraints. It combines several algorithms for prediction of secondary consensus structure and even tertiary interactions. The CONSTRUCT package can be downloaded from the URL listed in the Availability and

Construction and operation costs of constructed wetlands treating wastewater.

Science.gov (United States)

Gkika, Dimitra; Gikas, Georgios D; Tsihrintzis, Vassilios A

2014-01-01

Design data from nine constructed wetlands (CW) facilities of various capacities (population equivalent (PE)) are used to estimate construction and operation costs, and then to derive empirical equations relating the required facility land area and the construction cost to PE. In addition, comparisons between the costs of CW facilities based on various alternative construction materials, i.e., reinforced concrete and earth structures (covered with either high density polyethylene or clay), are presented in relation to the required area. The results show that earth structures are economically advantageous. The derived equations can be used for providing a preliminary cost estimate of CW facilities for domestic wastewater treatment.

40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

Science.gov (United States)

2010-07-01

... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment... Constructed on or Before September 20, 1994 § 60.33b Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals...

Active-Learning versus Teacher-Centered Instruction for Learning Acids and Bases

Science.gov (United States)

Sesen, Burcin Acar; Tarhan, Leman

2011-01-01

Background and purpose: Active-learning as a student-centered learning process has begun to take more interest in constructing scientific knowledge. For this reason, this study aimed to investigate the effectiveness of active-learning implementation on high-school students' understanding of "acids and bases". Sample: The sample of this…

Perspectives of construction robots

Science.gov (United States)

Stepanov, M. A.; Gridchin, A. M.

2018-03-01

This article is an overview of construction robots features, based on formulating the list of requirements for different types of construction robots in relation to different types of construction works.. It describes a variety of construction works and ways to construct new or to adapt existing robot designs for a construction process. Also, it shows the prospects of AI-controlled machines, implementation of automated control systems and networks on construction sites. In the end, different ways to develop and improve, including ecological aspect, the construction process through the wide robotization, creating of data communication networks and, in perspective, establishing of fully AI-controlled construction complex are formulated.

Graphene-Based Nanomaterials as Heterogeneous Acid Catalysts: A Comprehensive Perspective

Directory of Open Access Journals (Sweden)

Bhaskar Garg

2014-09-01

Full Text Available Acid catalysis is quite prevalent and probably one of the most routine operations in both industrial processes and research laboratories worldwide. Recently, “graphene”, a two dimensional single-layer carbon sheet with hexagonal packed lattice structure, imitative of nanomaterials, has shown great potential as alternative and eco-friendly solid carbocatalyst for a variety of acid-catalyzed reactions. Owing to their exceptional physical, chemical, and mechanical properties, graphene-based nanomaterials (G-NMs offer highly stable Brønsted acidic sites, high mass transfer, relatively large surface areas, water tolerant character, and convenient recoverability as well as recyclability, whilst retaining high activity in acid-catalyzed chemical reactions. This comprehensive review focuses on the chemistry of G-NMs, including their synthesis, characterization, properties, functionalization, and up-to-date applications in heterogeneous acid catalysis. In line with this, in certain instances readers may find herein some criticisms that should be taken as constructive and would be of value in understanding the scope and limitations of current approaches utilizing graphene and its derivatives for the same.

Shortening of construction period of nuclear power plant. Activities of construction industry on construction period shortening

International Nuclear Information System (INIS)

Kamata, Hirofumi

2011-01-01

Total construction period could be shorten by prefabricating structures efficiently in another yard and reducing working hours on site, which would reduce work at height or congestion work and also upgrade safety at work. Construction period shortening would surely reduce expenses during work and advance operation start of electric utilities. Construction of reactor building, turbine building, water intake and drainage canal was performed on a relatively large scale and a big share of whole schedule. This article summarized basic technologies to shorten construction period for reactor building/turbine building and water intake and drainage canal. Advanced methods of reactor building/turbine building; (1) modularization of equipment and skeleton, (2) utilization of concrete mold, reinforcing bar and steel frame, (3) precedent steel frame method and (4) steel plate reinforced concrete (SC) method, were outlined and their application examples were shown to reduce work on site and improve work efficiency. As for water intake and drainage canal construction, (1) precast concrete method, (2) SC method and (3) steel plate shell method were described with application examples. Construction procedures and problems using mega block method for water intake and drainage canal were also introduced. (T. Tanaka)

Constructed Wetlands

Science.gov (United States)

these systems can improve water quality, engineers and scientists construct systems that replicate the functions of natural wetlands. Constructed wetlands are treatment systems that use natural processes

Potential and Benefits of Building Information Modeling (BIM) During Pre-Construction, Construction and Post Construction Stage

OpenAIRE

Aw Nien Wei; Md Azree Othuman Mydin

2017-01-01

The construction industry is the main economic support for all countries around the world in which continually adapting to meet competitive challenges around the global market. Nevertheless, the construction project is becoming much more complex and difficult to manage. This is because the construction project involves a large number of stakeholder, for example, the consultant companies, architects, engineers, building surveyors and quantity surveyors. The technology current...

Survival and mutant production induced by mutagenic agents in Metarhizium anisopliae Sobrevivência e obtenção de mutantes induzidos por agentes mutagênicos em Metarhizium anisopliae

Directory of Open Access Journals (Sweden)

V. Kava - Cordeiro

1995-12-01

Full Text Available A wild strain of Metarhizium anisopliae, an entomopathogenic fungus, was submitted to three mutagenic agents: gamma radiation, ultraviolet light and nitrous acid. Survival curves were obtained and mutants were selected using different mutagenic doses which gave 1 to 5% survival. Morphological and auxotrophic mutants were isolated. Morphological mutants were grouped in a class with yellow conidia and other with pale vinaceous conidia as opposed to the green wild type conidia. Auxotrophic mutants had requirements for vitamin and aminoacid biosynthesis. More than 58% of the total auxotrophk mutants required proline/aipnine. Gamma radiation showed to be the most efficient mutagenic agent giving 0.2% of auxotrophk mutants followed by ultraviolet light (0.12% and nitrous acid (0.06%.The conidial colour and auxotrophk mutants isolated until now from M. anisopliae were reviewed.Uma linhagem selvagem do fungo entomopatogênico Metarhizium anisopliae foi submetida à ação de três agentes mutagênicos: radiação gama, luz ultravioleta e ácido nitroso. Curvas de sobrevivência foram obtidas para cada mutagênicos utilizado e mutantes foram selecionados a partir de doses dos mutagênicos que proporcionassem de 1 a 5% de sobrevivência. Mutantes morfológicos para a coloração de conídios e mutantes auxotróficos foram isolados. Mutantes para coloração de conidios foram agrupados em duas classes, uma com conídios amarelos e outra com conídios vinho pálido. Os mutantes auxotróficos obtidos foram deficientes para aminoácidos e vitaminas e mais de 58% deles eram auxotróficos para prolina/argmina. Radiação gama foi o mutagênico mais eficiente com uma porcentagem de obtenção de mulantes auxotróficos de aproximadamente 0,2%, seguido pela luz ultravioleta (0.12% e pelo ácido nitroso (0.06%.Os mulantes morfológicos e auxotróficos obtidos até o momento em Metarhizium anisopliae foram revistos.

FFTF constructibility

International Nuclear Information System (INIS)

Weber, S.A.; Hulbert, D.I.

1975-01-01

The influence of the design criteria on the constructibility of the Fast Flux Test Facility is described. Specifically, the effects of requirements due to maintenance accessibility, inerting of cells, seismicity, codes, and standards are addressed. The design and construction techniques developed to minimize the impact of the design criteria on cost and schedule are presented with particular emphasis on the cleanliness and humidity controls imposed during construction of the sodium systems. (U.S.)

Genonets server-a web server for the construction, analysis and visualization of genotype networks.

Science.gov (United States)

Khalid, Fahad; Aguilar-Rodríguez, José; Wagner, Andreas; Payne, Joshua L

2016-07-08

A genotype network is a graph in which vertices represent genotypes that have the same phenotype. Edges connect vertices if their corresponding genotypes differ in a single small mutation. Genotype networks are used to study the organization of genotype spaces. They have shed light on the relationship between robustness and evolvability in biological systems as different as RNA macromolecules and transcriptional regulatory circuits. Despite the importance of genotype networks, no tool exists for their automatic construction, analysis and visualization. Here we fill this gap by presenting the Genonets Server, a tool that provides the following features: (i) the construction of genotype networks for categorical and univariate phenotypes from DNA, RNA, amino acid or binary sequences; (ii) analyses of genotype network topology and how it relates to robustness and evolvability, as well as analyses of genotype network topography and how it relates to the navigability of a genotype network via mutation and natural selection; (iii) multiple interactive visualizations that facilitate exploratory research and education. The Genonets Server is freely available at http://ieu-genonets.uzh.ch. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

Reductive dehalogenation of haloacetic acids by hemoglobin-loaded carbon nanotube electrode.

Science.gov (United States)

Li, Yu-Ping; Cao, Hong-Bin; Zhang, Yi

2007-01-01

Hemoglobin (Hb) was immobilized on carbon nanotube (CNT) electrode to catalyze the dehalogenation of haloacetic acids (HAAs). FTIR and UV measurements were performed to investigate the activity-keep of Hb after immobilization on CNT. The electrocatalytic behaviors of the Hb-loaded electrode for the dehalogenation of HAAs were studied by cyclic voltammmetry and constant-potential electrolysis technique. An Hb-loaded packed-bed flow reactor was also constructed for bioelectrocatalytic dehalogenation of HAAs. The results showed that Hb retained its nature, the essential features of its native secondary structure, and its biocatalytic activity after immobilization on CNT. Chloroacetic acids and bromoacetic acids could be dehalogenated completely with Hb catalysis through a stepwise dehalogenation process at -0.400V (vs. saturated calomel electrode (SCE)) and -0.200V (vs. SCE), respectively. The removal of 10.5mM trichloroacetic acid and dichloroacetic acid is ca. 97% and 63%, respectively, with electrolysis for 300min at -0.400V (vs. SCE) using the Hb-loaded packed-bed flow reactor, and almost 100% of tribromoacetic acid and dibromoacetic acid was removed with electrolysis for 40min at -0.200V (vs. SCE). The average current efficiency of Hb-catalytic dehalogenation almost reaches 100%.

[Construction of a low-pH-sensing system in Streptococcus mutans].

Science.gov (United States)

Di, Kang; Yuqing, Li; Xuedong, Zhou

2017-06-01

To construct a low-pH-sensing system in Streptococcus mutans (S. mutans) and to visually detect the pH in situ. Promoter of ureaseⅠ(PureⅠ) and green fluorescence protein (gfp) DNA fragments were amplified by polymerase chain reaction (PCR) from the genome of Streptococcus salivarius 57.I and S. mutans containing the gfp fragment. The two amplified DNA fragments were ligated together and further integrated into pDL278 to construct the recombinant plasmid pDL278-pureⅠ-gfp. This recombinant plasmid was then transformed into S. mutans UA159 cells. Subsequently, the intensity of the optical density per unit area of the low-pH-sensing system was measured and compared under different pH conditions and different processing times. PureⅠ and gfp DNA fragments were amplified successfully with the correct molecule sizes (450 and 717 bp, respectively). The recombinant plasmid pDL278-pureⅠ-gfp was constructed and further verified by PCR and sequencing. The intensity of the optical density per unit area of the low-pH-sensing system increased with decreasing pH and increasing processing time. A low-pH-sensing system was constructed successfully in S. mutans. Our research verified that pureⅠ of Streptococcus salivarius can function well in S. mutans as an acid induced promoter, and provided a new method of detecting the pH of plaque biofilms in situ.

Synthesis of novel acid electrolytes for phosphoric acid fuel cells

Science.gov (United States)

Adcock, James L.

1988-11-01

A 40 millimole per hour scale aerosol direct fluorination reactor was constructed. F-Methyl F-4-methoxybutanoate and F-4-methoxybutanoyl fluoride were synthesized by aerosol direct fluorination of methyl 4-methoxybutanoate. Basic hydrolysis of the perfluorinated derivatives produce sodium F-4 methoxybutanoate which was pyrolyzed to F-3-methoxy-1-propene. Purification and shipment of 33 grams of F-3-methoxy-1-propene followed. Syntheses by analogous methods allowed production and shipment of 5 grams of F-3-ethoxy 1-propene, 18 grams of F-3-(2-methoxy.ethoxy) 1-propene, and 37 grams of F-3,3-dimethyl 1-butene. Eighteen grams of F-2,2-dimethyl 1-chloropropane was produced directly and shipped. As suggested by other contractors, 5 grams of F-3-methoxy 1-iodopropane, and 5 grams of F-3-(2-methoxy.ethoxy) 1-iodopropane were produced by converting the respective precursor acid sodium salts produced for olefin synthesis to the silver salts and pyrolyzing them with iodine. Each of these compounds was prepared for the first time by the aerosol fluorination process during the course of the contract. These samples were provided to other Gas Research Institute (GRI) contractors for synthesis of perfluorinated sulfur (VI) and phosphorous (V) acids.

Brucella, nitrogen and virulence.

Science.gov (United States)

Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

2016-08-01

The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

Versatile synthesis of amino acid functionalized nucleosides via a domino carboxamidation reaction

Directory of Open Access Journals (Sweden)

Vicky Gheerardijn

2014-11-01

Full Text Available Functionalized oligonucleotides have recently gained increased attention for incorporation in modified nucleic acid structures both for the design of aptamers with enhanced binding properties as well as the construction of catalytic DNA and RNA. As a shortcut alternative to the incorporation of multiple modified residues, each bearing one extra functional group, we present here a straightforward method for direct linking of functionalized amino acids to the nucleoside base, thus equipping the nucleoside with two extra functionalities at once. As a proof of principle, we have introduced three amino acids with functional groups frequently used as key-intermediates in DNA- and RNAzymes via an efficient and straightforward domino carboxamidation reaction.

Superface energy of several construction materials

Directory of Open Access Journals (Sweden)

Otero, J. L.

2006-09-01

Full Text Available Inverse gas chromatography at infinite dilution was used to characterize the surface of different construction materials (marble, sandstone, granite and brick. Surface energy can be divided into two components: dispersive and polar or acid-base. The highest dispersive energy value was found for sandstone, while the values for the other three materials were all very similar. The lower dispersive energy variation exhibited by sandstone with temperature changes is an indication that substances interact equally well with its surface at any temperature. All the materials were found to be amphoteric, with both acid and alkaline components, although acidity was greater in granite and brick and sandstone and marble had higher alkalinity.En este trabajo se ha realizado la caracterización de la superficie de diferentes materiales de construcción (mármol,arenisca, granito y ladrillo mediante cromatografía inversa gas-sólido a dilución infinita. La energía superficial se puede dividir en dos componentes: dispersiva y ácido-base. Los valores obtenidos para la energía dispersiva son bastante parecidas para mármol, granito y ladrillo, mientras que el valor más alto corresponde a la arenisca. Además, este material presenta una menor variación de la energía dispersiva con la temperatura lo que indica que la interacción de cualquier sustancia con su superficie se dará a cualquier temperatura. Por lo que respecta a las componentes ácido-base, se ha observado que todos los materiales poseen ambas componentes lo que indica un carácter anfótero, sin embargo, la acidez es mayor en el granito y en el ladrillo, mientras que la basicidad es mayor en la arenisca y en el mármol.

Aspergillus oryzae-based cell factory for direct kojic acid production from cellulose.

Science.gov (United States)

Yamada, Ryosuke; Yoshie, Toshihide; Wakai, Satoshi; Asai-Nakashima, Nanami; Okazaki, Fumiyoshi; Ogino, Chiaki; Hisada, Hiromoto; Tsutsumi, Hiroko; Hata, Yoji; Kondo, Akihiko

2014-05-18

Kojic acid (5-Hydroxy-2-(hydroxymethyl)-4-pyrone) is one of the major secondary metabolites in Aspergillus oryzae. It is widely used in food, pharmaceuticals, and cosmetics. The production cost, however, is too high for its use in many applications. Thus, an efficient and cost-effective kojic acid production process would be valuable. However, little is known about the complete set of genes for kojic acid production. Currently, kojic acid is produced from glucose. The efficient production of kojic acid using cellulose as an inexpensive substrate would help establish cost-effective kojic acid production. A kojic acid transcription factor gene over-expressing the A. oryzae strain was constructed. Three genes related to kojic acid production in this strain were transcribed in higher amounts than those found in the wild-type strain. This strain produced 26.4 g/L kojic acid from 80 g/L glucose. Furthermore, this strain was transformed with plasmid harboring 3 cellulase genes. The resultant A. oryzae strain successfully produced 0.18 g/L of kojic acid in 6 days of fermentation from the phosphoric acid swollen cellulose. Kojic acid was produced directly from cellulose material using genetically engineered A. oryzae. Because A. oryzae has efficient protein secretion ability and secondary metabolite productivity, an A. oryzae-based cell factory could be a platform for the production of various kinds of bio-based chemicals.

Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast

DEFF Research Database (Denmark)

Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam

2016-01-01

Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we...... developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter...... TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions...

Phylogenetic Analysis of Bacillus subtilis Strains Applicable to Natto (Fermented Soybean) Production ▿

Science.gov (United States)

Kubo, Yuji; Rooney, Alejandro P.; Tsukakoshi, Yoshiki; Nakagawa, Rikio; Hasegawa, Hiromasa; Kimura, Keitarou

2011-01-01

Spore-forming Bacillus strains that produce extracellular poly-γ-glutamic acid were screened for their application to natto (fermented soybean food) fermentation. Among the 424 strains, including Bacillus subtilis and B. amyloliquefaciens, which we isolated from rice straw, 59 were capable of fermenting natto. Biotin auxotrophism was tightly linked to natto fermentation. A multilocus nucleotide sequence of six genes (rpoB, purH, gyrA, groEL, polC, and 16S rRNA) was used for phylogenetic analysis, and amplified fragment length polymorphism (AFLP) analysis was also conducted on the natto-fermenting strains. The ability to ferment natto was inferred from the two principal components of the AFLP banding pattern, and natto-fermenting strains formed a tight cluster within the B. subtilis subsp. subtilis group. PMID:21764950

Initiation in the study of uranium recovery from the phosphoric acid

Energy Technology Data Exchange (ETDEWEB)

Anchondo Adalid, J M

1974-01-01

The loss of considerable amounts of uranium in the Mexican phosphoric acid industry makes it important to study economic methods of recovery; the studies can serve as a basis for the construction and operation of a pilot plant as a normal preliminary to larger-scale projects. Routine experimental techniques for solvent extraction were employed. Extraction efficiencies of the order of 90-95% were obtained using 0.09-0.18M solutions of a mixture of phosphoric octyl esters applied to 4 and 6M solutions of phosphoric acid (reagent grade) containing uranium in concentrations of 0.05-0.50g of U/sub 3/O/sub 8/ per litre of acid. The conclusion was reached that phosphoric octyl esters can be used for recovering uranium in satisfactory quantities from phosphoric acid solutions by means of solvent extraction, and that the uranium can be separated from the solvent by the established procedures.

Initiation in the study of uranium recovery from the phosphoric acid

International Nuclear Information System (INIS)

Anchondo Adalid, J.M.

1974-01-01

The loss of considerable amounts of uranium in the Mexican phosphoric acid industry makes it important to study economic methods of recovery; the studies can serve as a basis for the construction and operation of a pilot plant as a normal preliminary to larger-scale projects. Routine experimental techniques for solvent extraction were employed. Extraction efficiencies of the order of 90-95% were obtained using 0.09-0.18M solutions of a mixture of phosphoric octyl esters applied to 4 and 6M solutions of phosphoric acid (reagent grade) containing uranium in concentrations of 0.05-0.50g of U 3 O 8 per litre of acid. The conclusion was reached that phosphoric octyl esters can be used for recovering uranium in satisfactory quantities from phosphoric acid solutions by means of solvent extraction, and that the uranium can be separated from the solvent by the established procedures. (author)

A new approach for noninvasive transdermal determination of blood uric acid levels

Directory of Open Access Journals (Sweden)

Ching CTS

2014-06-01

Full Text Available Congo Tak-Shing Ching,1,2 Kok-Khun Yong,3 Yan-Dong Yao,4 Huan-Ting Shen,3 Shiu-Man Hsieh,5 Deng-Yun Jheng,1 Tai-Ping Sun,1,6 Hsiu-Li Shieh11Department of Electrical Engineering, National Chi Nan University, Nantou, 2Department of Photonics and Communication Engineering, Asia University, Taichung, 3Department of Internal Medicine, Puli Christian Hospital, Nantou, People’s Republic of China; 4Division of Science and Technology, Hong Kong Community College, Hong Kong; 5Department of Orthopedic Surgery, Puli Christian Hospital, 6Department of Electronic Engineering, Nan Kai University of Technology, Nantou, People’s Republic of ChinaAbstract: The aims of this study were to investigate the most effective combination of physical forces from laser, electroporation, and reverse iontophoresis for noninvasive transdermal extraction of uric acid, and to develop a highly sensitive uric acid biosensor (UAB for quantifying the uric acid extracted. It is believed that the combination of these physical forces has additional benefits for extraction of molecules other than uric acid from human skin. A diffusion cell with porcine skin was used to investigate the most effective combination of these physical forces. UABs coated with ZnO2 nanoparticles and constructed in an array configuration were developed in this study. The results showed that a combination of laser (0.7 W, electroporation (100 V/cm2, and reverse iontophoresis (0.5 mA/cm2 was the most effective and significantly enhanced transdermal extraction of uric acid. A custom-designed UAB coated with ZnO2 nanoparticles and constructed in a 1×3 array configuration (UAB-1×3-ZnO2 demonstrated enough sensitivity (9.4 µA/mM for quantifying uric acid extracted by the combined physical forces of laser, electroporation, and RI. A good linear relationship (R2=0.894 was demonstrated to exist between the concentration of uric acid (0.2–0.8 mM inside the diffusion cell and the current response of the

Caged molecular beacons: controlling nucleic acid hybridization with light.

Science.gov (United States)

Wang, Chunming; Zhu, Zhi; Song, Yanling; Lin, Hui; Yang, Chaoyong James; Tan, Weihong

2011-05-28

We have constructed a novel class of light-activatable caged molecular beacons (cMBs) that are caged by locking two stems with a photo-labile biomolecular interaction or covalent bond. With the cMBs, the nucleic acid hybridization process can be easily controlled with light, which offers the possibility for a high spatiotemporal resolution study of intracellular mRNAs. © The Royal Society of Chemistry 2011

Construction and Selection of Affilin® Phage Display Libraries.

Science.gov (United States)

Settele, Florian; Zwarg, Madlen; Fiedler, Sebastian; Koscheinz, Daniel; Bosse-Doenecke, Eva

2018-01-01

Affilin ® molecules represent a new class of so-called scaffold proteins. The concept of scaffold proteins is to use stable and versatile protein structures which can be endowed with de novo binding properties and specificities by introducing mutations in surface exposed amino acid residues. Complex variations and combinations are generated by genetic methods of randomization resulting in large cDNA libraries. The selection for candidates binding to a desired target can be executed by display methods, especially the very robust and flexible phage display. Here, we describe the construction of ubiquitin based Affilin ® phage display libraries and their use in biopanning experiments for the identification of novel protein ligands.

Leadership Quality for Malaysia Construction Leader to Steer a Success Construction Project

OpenAIRE

Ngah Nasaruddin Nur Ain; Abdul Rahman Ismail

2016-01-01

Issues that dominate the construction industry for the long time such as time overrun, cost overrun, quality of construction and also safety during the construction process are difficult to resolve because of several factors involved which amongst them are leadership quality in the industry. Solving these issues can make the industry more sustainable in nature. This paper presents the need of leadership quality among construction parties involved to steer a construction project successfully. ...

Heterotic string construction

International Nuclear Information System (INIS)

Schellekens, A.N.

1989-01-01

In this paper an elementary introduction to the principles of four-dimensional string construction will be given. Although the emphasis is on lattice constructions, almost all results have further, and often quite straightforward generalizations to other constructions. Since heterotic strings look phenomenologically more promising than type-II theories the authors only consider the former, although everything can easily be generalized to type-II theories. Some additional aspects of lattice constructions are discussed, and an extensive review can be found

77 FR 49722 - Cranes and Derricks in Construction: Demolition and Underground Construction

Science.gov (United States)

2012-08-17

... underground construction work. Therefore, when OSHA promulgates a new final rule, states and territories with... used in construction work. For most construction work, the final rule replaced a prior cranes and... construction work. Through this direct final rule, OSHA is applying the updated requirements to that work. With...

WEB-server for search of a periodicity in amino acid and nucleotide sequences

Science.gov (United States)

E Frenkel, F.; Skryabin, K. G.; Korotkov, E. V.

2017-12-01

A new web server (http://victoria.biengi.ac.ru/splinter/login.php) was designed and developed to search for periodicity in nucleotide and amino acid sequences. The web server operation is based upon a new mathematical method of searching for multiple alignments, which is founded on the position weight matrices optimization, as well as on implementation of the two-dimensional dynamic programming. This approach allows the construction of multiple alignments of the indistinctly similar amino acid and nucleotide sequences that accumulated more than 1.5 substitutions per a single amino acid or a nucleotide without performing the sequences paired comparisons. The article examines the principles of the web server operation and two examples of studying amino acid and nucleotide sequences, as well as information that could be obtained using the web server.

HITACHI construction CAE system

International Nuclear Information System (INIS)

Yoshida, M.

1994-01-01

Construction and maintenance of nuclear power plants have important problems such as shortening the construction period and reducing the construction cost. Recently, the problem of insufficient construction labor has arisen, and as drastic strategic development has become a necessary counter-measure. The following four principles are included in the measures to be taken for efficient execution of the construction work within the short construction period: (1) reduction of on-site work and expansion of module block making, (2)improvement of the accuracy of the on-site work process, adjustment and expansion of the work in parallel with the construction process, (3)improvement of efficiency of the on-site work and mechanization and automation of the work, (4)improvement of the accuracy of the management of the construction. A three dimensional simulation system plant construction plan CAE, comprising five modules has been developed. A project management system was also developed to improve the accuracy and efficiency of management work in the field

New trends and challenges in lactic acid production on renewable biomass

Directory of Open Access Journals (Sweden)

Đukić-Vuković Aleksandra J.

2011-01-01

Full Text Available Lactic acid is a relatively cheap chemical with a wide range of applications: as a preservative and acidifying agent in food and dairy industry, a monomer for biodegradable poly-lactide polymers (PLA in pharmaceutical industry, precursor and chemical feedstock for chemical, textile and leather industries. Traditional raw materials for fermentative production of lactic acid, refined sugars, are now being replaced with starch from corn, rice and other crops for industrial production, with a tendency for utilization of agro industrial wastes. Processes based on renewable waste sources have ecological (zero CO2 emission, eco-friendly by-products and economical (cheap raw materials, reduction of storage costs advantages. An intensive research interest has been recently devoted to develop and improve the lactic acid production on more complex industrial by-products, like thin stillage from bioethanol production, corncobs, paper waste, straw etc. Complex and variable chemical composition and purity of these raw materials and high nutritional requirements of Lare the main obstacles in these production processes. Media supplementation to improve the fermentation is an important factor, especially from an economic point of view. Today, a particular challenge is to increase the productivity of lactic acid production on complex renewable biomass. Several strategies are currently being explored for this purpose such as process integration, use of Lwith amylolytic activity, employment of mixed cultures of Land/or utilization of genetically engineered microorganisms. Modern techniques of genetic engineering enable construction of microorganisms with desired characteristics and implementation of single step processes without or with minimal pre-treatment. In addition, new bioreactor constructions (such as membrane bioreactors, utilization of immobilized systems are also being explored. Electrodialysis, bipolar membrane separation process, enhanced filtration

Three two-dimensional coordination polymers constructed from transition metals and 2,3-norbornanedicarboxylic acid: Hydrothermal synthesis, crystal structures and photocatalytic properties

Science.gov (United States)

Zhang, Jia; Wang, Chong-Chen

2017-02-01

Three novel coordination polymers based on transition metals like Co(II), Cu(II) and Mn(II), namely [Co2(bpy)2(nbda)2(H2O)2]·2H2O (denoted as BUC-1), [Cu2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-2), [Mn2(bpy)2(nbda)2(H2O)2]·2H2O (BUC-3), (where bpy = 4,4‧-bipyridine, H2nbda = 2,3-norbornanedicarboxylic acid, BUC = Beijing University of Civil Engineering and Architecture), were synthesized under hydrothermal conditions, and characterized by CNH elemental analyses (EA), Fourier Transform infrared spectroscopy (FTIR), and single crystal X-ray diffraction (SCXRD). BUC 1-3 were isostructural and crystallized in the monoclinic space group C2/c, in which the corresponding metal atoms were linked by typical bidentate bpy ligands into two adjacent 1D [M1(bpy)]n2n+ and [M2(bpy)]n2n+ (M = Co(II), Cu(II), Mn(II)), further joined by versatile nbda2- ligands into 2D [M2(bpy)2(nbda)2]n sheets. Finally, three-dimensional supramolecular frameworks were constructed with the aid of the intermolecular hydrogen bonding interactions. BUC 1-3 exhibited different photocatalytic degradation ability to decompose methylene blue (MB) and methyl orange (MO) under UV light irradiation. Additionally, a possible photocatalytic mechanism HOMO-LUMO was proposed and discussed, which was further confirmed by radicals trapping experiments using isopropanol as radical scavenger.

77 FR 49741 - Cranes and Derricks in Construction: Demolition and Underground Construction

Science.gov (United States)

2012-08-17

..., subpart CC, to replace the earlier rule (Sec. 1926.550) for all construction work.\\1\\ In proposing the new... derricks used in construction work. For most construction work, the final rule replaced a prior cranes and... construction work. Through this proposed rule, OSHA is proposing to apply the updated requirements to that work...

How Can Lean Construction Improve the Daily Schedule of A Construction Manager?

Science.gov (United States)

Binninger, Marco; Dlouhy, Janosch; Schneider, Johannes; Haghsheno, Shervin

2017-10-01

The outcome of construction projects highly depends on effective management. The site manager is responsible for the site, and has a key role in executing construction projects. Especially this position has a wide range of tasks and a high volume of workload, which has to be carried out in a high pressure and high stress environment. Chaotic construction processes often create these working conditions. Lean Construction can help to organize the construction site in a better way and automatically supports the site manager.

COUNTERBALANCING BENEFITS AND DRAWBACKS OF CONTEMPORARY STABLISED EARTH CONSTRUCTION BY CONSTRUCTION PROFESSIONALS

Directory of Open Access Journals (Sweden)

Mohammad Sharif Zami

2011-07-01

Full Text Available It is debatable among the construction professionals whether contemporary stabilised earth construction is beneficial in urban low cost housing. Existing literature recorded a lot of benefits and drawbacks from construction professionals, which is empirically substantiated. But there are drawbacks found in the literature that seemingly are conflicting, and construction professionals are divided in their opinion. This paper seeks to address these conflicts and division by validating the controversial drawbacks of contemporary stabilised earth construction in urban low cost housing.

Quantification of nitrogen in the liquid fraction and in vitro assessment of lysine bioavailability in the solid fraction of soybean meal hydrolysates.

Science.gov (United States)

Luján-Rhenals, D; Morawicki, R; Shi, Z; Ricke, S C

2018-01-02

Soybean meal (SBM) is a product generated from the manufacture of soybean oil and has the potential for use as a source of fermentable sugars for ethanol production or as a protein source for animal feeds. Knowing the levels of nitrogen available from ammonium is a necessary element of the ethanolic fermentation process while identifying the levels of essential amino acids such as lysine is important in determining usage as a feed source. As such the purpose of this study was to quantify total nitrogen and ammonium in the liquid fraction of hydrolyzed SBM and to evaluate total and bioavailable lysine in the solid fraction of the hydrolyzed SBM. The effects of acid concentration, cellulase and β-glucosidase on total and ammonium nitrogen were studied with analysis indicating that higher acid concentrations increased nitrogen compounds with ammonium concentrations ranging from 0.20 to 1.24 g L -1 while enzymatic treatments did not significantly increase nitrogen levels. Total and bioavailable lysine was quantified by use of an auxotrophic gfpmut3 E.coli whole-cell bioassay organism incapable of lysine biosynthesis. Acid and enzymatic treatments were applied with lysine bioavailability increasing from a base of 82% for untreated SBM to up to 97%. Our results demonstrated that SBM has the potential to serve in ethanolic fermentation and as an optimal source essential amino acid lysine.

Evidence that survival of γ-irradiated Escherichia coli is influenced by membrane fluidity

International Nuclear Information System (INIS)

Yatvin, M.B.

1976-01-01

Survival studies have been carried out on an Escherichia coli auxotroph (K-12 strain K1060) defective in both fatty acid degradation and in unsaturated fatty acid biosynthesis. Cultures were grown overnight in media supplemented with either oleic or linolenic acid, and γ-irradiated at two temperatures. Gas chromatography of total cellular fatty acids demonstrated marked differences in the compositions. In the bacteria grown in oleate, plamitate accounted for 35% and oleate 43%, whereas those grown in linolenate had no oleate but contained 56% palmitate and 35% linolenate. The loss (35%) in total DNA radioactivity from ( 3 H)TdR labelled cells after irradiation at room temperature or on ice, was essentially the same in bacteria grown with linoleic or oleic acid medium. The survival of linolenic substituted bacteria was altered little by irradiation at ice-bath temperature, but the oleic-grown bacteria were much more radiosensitive when irradiated and plated from the cold. The temperatures of the membrane phase transitions are such that at ice-bath temperature (approximately 3 to 5 0 C) only the membrane of the linolenate grown bacteria could possibly still be in the liquid (unorganized) state. The results therefore indicate that one of the factors influencing survival of irradiated bacteria may be membrane fluidity, and the membranes are an important factor in determining the extent of damage, 'repair' and ultimate survival in irradiated cells. (U.K.)

Managing Pre-Construction and Construction Risks on Project Sites in Abuja-Nigeria

Directory of Open Access Journals (Sweden)

Jimoh R.A.

2016-03-01

Full Text Available Managing risks in construction projects has been acknowledged as a key direction process for the purposes of attaining the project goal in terms of time, cost, quality, safety, and environmental sustainability. Hence, the paper evaluated pre-construction and construction risks on active project sites in Abuja-Nigeria. This was achieved using survey method through the self-administration of 35 questionnaires to the professionals handling the 35 identified projects being undertaking at that time. Results showed that errors and omissions in design and improperly defined project scope had mean score values of 3.03 and 2.54, respectively, were the construction risks most experienced by the professionals during pre-construction. On the other hand, fluctuation in market prices and delays with mean score values of 3.14 and 2.74, respectively, were the construction risks experienced by the professionals during the construction phase of the projects. It is recommended that procurement methods such as construction management should be adopted and stakeholders should keep to their own side of the bargain to avoid unnecessary delays.

Construction fraud

NARCIS (Netherlands)

Graafland, J.J.; Liedekerke, L.; Dubbink, W.; van Liedekerke, L.; van Luijk, H.

2011-01-01

Due to the actions of a whistleblower The Netherlands was confronted with a massive case of construction fraud involving almost the entire construction sector. Price fixing, prior consulting, duplicate accounts, fictitious invoices and active corruption of civil servants were rampant practices. This

How engineering facilitates construction

International Nuclear Information System (INIS)

Bailey, D.T.

1976-01-01

During a recent survey, construction personnel at jobsites were asked, ''what are the ten most unwanted construction problems.'' One reoccurring answer was design/construction incompatibility. In fact, many designs were impractical from a construction point of view. The reasons for this problem can be identified: Once construction begins, engineering is under intense pressure to issue new drawings to allow work to progress according to schedule. Other reasons may be the relative inexperience of the design personnel in construction, changes in design criteria and delays in receipt of supplier or client information. A description is presented of ways to solve this problem by obtaining construction expertise and input into the various phases and products of the engineering work

Net alkalinity and net acidity 1: Theoretical considerations

International Nuclear Information System (INIS)

Kirby, Carl S.; Cravotta, Charles A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO 2 , and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined 'CO 2 -acidity' is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO 2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass-action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mgL -1 as CaCO 3 (based on pH and analytical concentrations of dissolved Fe II , Fe III , Mn, and Al in mgL -1 ):acidity calculated =50{1000(10 -pH )+[2(Fe II )+3(Fe III )]/56+2(Mn) /55+3(Al)/27}underestimates contributions from HSO 4 - and H + , but overestimates the acidity due to Fe 3+ and Al 3+ . However, these errors tend to approximately cancel each other. It is demonstrated that 'net alkalinity' is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the

Application and Mechanics Analysis of Multi-Function Construction Platforms in Prefabricated-Concrete Construction

Science.gov (United States)

Wang, Meihua; Li, Rongshuai; Zhang, Wenze

2017-11-01

Multi-function construction platforms (MCPs) as an “old construction technology, new application” of the building facade construction equipment, its efforts to reduce labour intensity, improve labour productivity, ensure construction safety, shorten the duration of construction and other aspects of the effect are significant. In this study, the functional analysis of the multi-function construction platforms is carried out in the construction of the assembly building. Based on the general finite element software ANSYS, the static calculation and dynamic characteristics analysis of the MCPs structure are analysed, the simplified finite element model is constructed, and the selection of the unit, the processing and solution of boundary are under discussion and research. The maximum deformation value, the maximum stress value and the structural dynamic characteristic model are obtained. The dangerous parts of the platform structure are analysed, too. Multiple types of MCPs under engineering construction conditions are calculated, so as to put forward the rationalization suggestions for engineering application of the MCPs.

Construction of the yeast whole-cell Rhizopus oryzae lipase biocatalyst with high activity.

Science.gov (United States)

Chen, Mei-ling; Guo, Qin; Wang, Rui-zhi; Xu, Juan; Zhou, Chen-wei; Ruan, Hui; He, Guo-qing

2011-07-01

Surface display is effectively utilized to construct a whole-cell biocatalyst. Codon optimization has been proven to be effective in maximizing production of heterologous proteins in yeast. Here, the cDNA sequence of Rhizopus oryzae lipase (ROL) was optimized and synthesized according to the codon bias of Saccharomyces cerevisiae, and based on the Saccharomyces cerevisiae cell surface display system with α-agglutinin as an anchor, recombinant yeast displaying fully codon-optimized ROL with high activity was successfully constructed. Compared with the wild-type ROL-displaying yeast, the activity of the codon-optimized ROL yeast whole-cell biocatalyst (25 U/g dried cells) was 12.8-fold higher in a hydrolysis reaction using p-nitrophenyl palmitate (pNPP) as the substrate. To our knowledge, this was the first attempt to combine the techniques of yeast surface display and codon optimization for whole-cell biocatalyst construction. Consequently, the yeast whole-cell ROL biocatalyst was constructed with high activity. The optimum pH and temperature for the yeast whole-cell ROL biocatalyst were pH 7.0 and 40 °C. Furthermore, this whole-cell biocatalyst was applied to the hydrolysis of tributyrin and the resulted conversion of butyric acid reached 96.91% after 144 h.

Modification of nucleic acids by azobenzene derivatives and their applications in biotechnology and nanotechnology.

Science.gov (United States)

Li, Jing; Wang, Xingyu; Liang, Xingguo

2014-12-01

Azobenzene has been widely used as a photoregulator due to its reversible photoisomerization, large structural change between E and Z isomers, high photoisomerization yield, and high chemical stability. On the other hand, some azobenzene derivatives can be used as universal quenchers for many fluorophores. Nucleic acid is a good candidate to be modified because it is not only the template of gene expression but also widely used for building well-organized nanostructures and nanodevices. Because the size and polarity distribution of the azobenzene molecule is similar to a nucleobase pair, the introduction of azobenzene into nucleic acids has been shown to be an ingenious molecular design for constructing light-switching biosystems or light-driven nanomachines. Here we review recent advances in azobenzene-modified nucleic acids and their applications for artificial regulation of gene expression and enzymatic reactions, construction of photoresponsive nanostructures and nanodevices, molecular beacons, as well as obtaining structural information using the introduced azobenzene as an internal probe. In particular, nucleic acids bearing multiple azobenzenes can be used as a novel artificial nanomaterial with merits of high sequence specificity, regular duplex structure, and high photoregulation efficiency. The combination of functional groups with biomolecules may further advance the development of chemical biotechnology and biomolecular engineering. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Murine protein H is comprised of 20 repeating units, 61 amino acids in length

DEFF Research Database (Denmark)

Kristensen, Torsten; Tack, B F

1986-01-01

A cDNA library constructed from size-selected (greater than 28 S) poly(A)+ RNA isolated from the livers of C57B10. WR mice was screened by using a 249-base-pair (bp) cDNA fragment encoding 83 amino acid residues of human protein H as a probe. Of 120,000 transformants screened, 30 hybridized......, 448 bp of 3'-untranslated sequence, and a polyadenylylated tail of undetermined length. Murine pre-protein H was deduced to consist of an 18-amino acid signal peptide and 1216 residues of H-protein sequence. Murine H was composed of 20 repetitive units, each about 61 amino acid residues in length...

PWR plant construction in Japan

International Nuclear Information System (INIS)

Tamura, Toshifumi

2002-01-01

The construction methods based on the experiences on the Nuclear Island, which is a critical path in the total construction schedule, have been studied and reconsidered in order to construct by more reliable and economical method. So various improved construction method are being applied and the duration of construction is being reduced continuously. So various improved construction method are being applied and the duration of construction is being reduced continuously. In this paper, the history of construction of twenty-three (23) PWR Plant, the actual construction methods and schedule of Ohi-3/4, to which the many improved methods were applied during their construction, are introduced mainly with the improved points for previously constructed plants. And also the situation of construction method for the next PWR Plant is simply explained

Benzoic acid fermentation from starch and cellulose via a plant-like β-oxidation pathway in Streptomyces maritimus

Directory of Open Access Journals (Sweden)

Noda Shuhei

2012-04-01

Full Text Available Abstract Background Benzoic acid is one of the most useful aromatic compounds. Despite its versatility and simple structure, benzoic acid production using microbes has not been reported previously. Streptomyces are aerobic, Gram-positive, mycelia-forming soil bacteria, and are known to produce various kinds of antibiotics composed of many aromatic residues. S. maritimus possess a complex amino acid modification pathway and can serve as a new platform microbe to produce aromatic building-block compounds. In this study, we carried out benzoate fermentation using S. maritimus. In order to enhance benzoate productivity using cellulose as the carbon source, we constructed endo-glucanase secreting S. maritimus. Results After 4 days of cultivation using glucose, cellobiose, or starch as a carbon source, the maximal level of benzoate reached 257, 337, and 460 mg/l, respectively. S. maritimus expressed β-glucosidase and high amylase-retaining activity compared to those of S. lividans and S. coelicolor. In addition, for effective benzoate production from cellulosic materials, we constructed endo-glucanase-secreting S. maritimus. This transformant efficiently degraded the phosphoric acid swollen cellulose (PASC and then produced 125 mg/l benzoate. Conclusions Wild-type S. maritimus produce benzoate via a plant-like β-oxidation pathway and can assimilate various carbon sources for benzoate production. In order to encourage cellulose degradation and improve benzoate productivity from cellulose, we constructed endo-glucanase-secreting S. maritimus. Using this transformant, we also demonstrated the direct fermentation of benzoate from cellulose. To achieve further benzoate productivity, the L-phenylalanine availability needs to be improved in future.

Obtention process of phosphorus 32 starting from commercial sulfur and design and construction of the radiochemical separation prototype

International Nuclear Information System (INIS)

Duarte A, C.; Alanis M, J.; Gutierrez R, C.

2002-01-01

In this work an obtention process of phosphorus 32 ( 32 P) in orthophosphoric acid form (H 3 32 PO 4 ) is described starting from commercial sulfur. Also the design and construction of the experimental prototype used in the radiochemical separation and their results in three tests carried out is reported. (Author)

Monitoring Bone Tissue Engineered (BTE) Constructs Based on the Shifting Metabolism of Differentiating Stem Cells.

Science.gov (United States)

Simmons, Aaron D; Sikavitsas, Vassilios I

2018-01-01

Ever-increasing demand for bone grafts necessitates the realization of clinical implementation of bone tissue engineered constructs. The predominant hurdle to implementation remains to be securing FDA approval, based on the lack of viable methods for the rigorous monitoring of said constructs. The study presented herein details a method for such monitoring based on the shifting metabolism of mesenchymal stem cells (MSCs) as they differentiate into osteoblasts. To that end, rat MSCs seeded on 85% porous spunbonded poly(L-lactic acid) scaffolds were cultured in flow perfusion bioreactors with baseline or osteoinductive media, and levels of key physio-metabolic markers (oxygen, glucose, osteoprotegerin, and osteocalcin) were monitored throughout culture. Comparison of these non-destructively obtained values and current standard destructive analyses demonstrated key trends useful for the concurrent real-time monitoring of construct cellularity and maturation. Principle among these is the elucidation of the ratio of the rates of oxygen uptake to glucose consumption as a powerful quality marker. This ratio, supported on a physiological basis, has been shown herein to be reliable in the determination of both construct maturation (defined as osteoblastic differentiation and accompanying mineralization) and construct cellularity. Supplementary monitoring of OPG and OCN are shown to provide further validation of such metrics.

Amino Acid Signatures to Evaluate the Beneficial Effects of Weight Loss

Directory of Open Access Journals (Sweden)

Nina Geidenstam

2017-01-01

Full Text Available Aims. We investigated the relationship between circulating amino acid levels and obesity; to what extent weight loss followed by weight maintenance can correct amino acid abnormalities; and whether amino acids are related to weight loss. Methods. Amino acids associated with waist circumference (WC and BMI were studied in 804 participants from the Malmö Diet and Cancer Cardiovascular Cohort (MDC-CC. Changes in amino acid levels were analyzed after weight loss and weight maintenance in 12 obese subjects and evaluated in a replication cohort (n=83. Results. Out of the eight identified BMI-associated amino acids from the MDC-CC, alanine, isoleucine, tyrosine, phenylalanine, and glutamate decreased after weight loss, while asparagine increased after weight maintenance. These changes were validated in the replication cohort. Scores that were constructed based on obesity-associated amino acids and known risk factors decreased in the ≥10% weight loss group with an associated change in BMI (R2=0.16–0.22, p<0.002, whereas the scores increased in the <10% weight loss group (p<0.0004. Conclusions. Weight loss followed by weight maintenance leads to differential changes in amino acid levels associated with obesity. Treatment modifiable scores based on epidemiological and interventional data may be used to evaluate the potential metabolic benefit of weight loss.

Visualization of construction engineering

International Nuclear Information System (INIS)

Okada, Hisako; Miura, Jun

2000-01-01

It is required for nuclear power plant construction to reduce construction cost and shorten construction period. An early and accurate construction planning including schedule coordination among the companies has recently become more important and it is possible to obtain necessary information for construction planning in early stage. In this situation, we have been developing a visualization system for construction engineering for nuclear power plants. This system has an interface with the existing Plant Layout 3D-CAD system and consists of three sub systems: (1) Scheduling and simulation system, (2) Yard planning system and (3) Scaffolding planning system. This paper describes overview of this system. This visualization system is very helpful for construction engineers to easily understand situation and environment around installation area, to easily plan a work sequence and confirm the planned schedule, and it is also effective for customers and workers to understand the planning. As a result, this visualization system enables safety and high quality construction. (author)

Residue Geometry Networks: A Rigidity-Based Approach to the Amino Acid Network and Evolutionary Rate Analysis

Science.gov (United States)

Fokas, Alexander S.; Cole, Daniel J.; Ahnert, Sebastian E.; Chin, Alex W.

2016-01-01

Amino acid networks (AANs) abstract the protein structure by recording the amino acid contacts and can provide insight into protein function. Herein, we describe a novel AAN construction technique that employs the rigidity analysis tool, FIRST, to build the AAN, which we refer to as the residue geometry network (RGN). We show that this new construction can be combined with network theory methods to include the effects of allowed conformal motions and local chemical environments. Importantly, this is done without costly molecular dynamics simulations required by other AAN-related methods, which allows us to analyse large proteins and/or data sets. We have calculated the centrality of the residues belonging to 795 proteins. The results display a strong, negative correlation between residue centrality and the evolutionary rate. Furthermore, among residues with high closeness, those with low degree were particularly strongly conserved. Random walk simulations using the RGN were also successful in identifying allosteric residues in proteins involved in GPCR signalling. The dynamic function of these residues largely remain hidden in the traditional distance-cutoff construction technique. Despite being constructed from only the crystal structure, the results in this paper suggests that the RGN can identify residues that fulfil a dynamical function. PMID:27623708

TPX tokamak construction management

International Nuclear Information System (INIS)

Knutson, D.; Kungl, D.; Seidel, P.; Halfast, C.

1995-01-01

A construction management contract normally involves the acquisition of a construction management firm to assist in the design, planning, budget conformance, and coordination of the construction effort. In addition the construction management firm acts as an agent in the awarding of lower tier contracts. The TPX Tokamak Construction Management (TCM) approach differs in that the construction management firm is also directly responsible for the assembly and installation of the tokamak including the design and fabrication of all tooling required for assembly. The Systems Integration Support (SIS) contractor is responsible for the architect-engineering design of ancillary systems, such as heating and cooling, buildings, modifications and site improvements, and a variety of electrical requirements, including switchyards and >4kV power distribution. The TCM will be responsible for the procurement of materials and the installation of the ancillary systems, which can either be performed directly by the TCM or subcontracted to a lower tier subcontractor. Assurance that the TPX tokamak is properly assembled and ready for operation when turned over to the operations team is the primary focus of the construction management effort. To accomplish this a disciplined constructability program will be instituted. The constructability effort will involve the effective and timely integration of construction expertise into the planning, component design, and field operations. Although individual component design groups will provide liaison during the machine assembly operations, the construction management team is responsible for assembly

Analytical methods for analysis of neutron cross sections of amino acids and proteins

International Nuclear Information System (INIS)

Voi, Dante L.; Ferreira, Francisco de O.; Nunes, Rogerio Chaffin; Carvalheira, Luciana; Rocha, Hélio F. da

2017-01-01

Two unpublished analytical processes were developed at IEN-CNEN-RJ for the analysis of neutron cross sections of chemical compounds and complex molecules, the method of data parceling and grouping (P and G) and the method of data equivalence and similarity (E and S) of cross-sections. The former allows the division of a complex compound or molecule so that the parts can be manipulated to construct a value of neutron cross section for the compound or the entire molecule. The second method allows by comparison obtain values of neutron cross-sections of specific parts of the compound or molecule, as the amino acid radicals or its parts. The processes were tested for the determination of neutron cross-sections of the 20 human amino acids and a small database was built for future use in the construction of neutron cross-sections of proteins and other components of the human being cells, also in other industrial applications. (author)

Analytical methods for analysis of neutron cross sections of amino acids and proteins

Energy Technology Data Exchange (ETDEWEB)

Voi, Dante L.; Ferreira, Francisco de O.; Nunes, Rogerio Chaffin; Carvalheira, Luciana, E-mail: dante@ien.gov.br, E-mail: fferreira@ien.gov.br, E-mail: Chaffin@ien.gov.br, E-mail: luciana@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Rocha, Hélio F. da, E-mail: helionutro@gmail.com.br [Universidade Federal do Rio de Janeiro (IPPMG/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Pediatria

2017-07-01

Two unpublished analytical processes were developed at IEN-CNEN-RJ for the analysis of neutron cross sections of chemical compounds and complex molecules, the method of data parceling and grouping (P and G) and the method of data equivalence and similarity (E and S) of cross-sections. The former allows the division of a complex compound or molecule so that the parts can be manipulated to construct a value of neutron cross section for the compound or the entire molecule. The second method allows by comparison obtain values of neutron cross-sections of specific parts of the compound or molecule, as the amino acid radicals or its parts. The processes were tested for the determination of neutron cross-sections of the 20 human amino acids and a small database was built for future use in the construction of neutron cross-sections of proteins and other components of the human being cells, also in other industrial applications. (author)

Construction Management.

Science.gov (United States)

Abbott, James F.

This article provides a detailed discussion of a team approach to building that involves a construction manager, an architect, and a contractor. Bidding methods are outlined; the major components in construction management -- value engineering and fast track scheduling -- and the use of performance specifications are discussed. The construction…

Structural Basis for Catalysis by the Mono and Dimetalated forms of the dapE-encoded N-succinyl-L,L-Diaminopimelic Acid Desuccinylase

OpenAIRE

Nocek, Boguslaw P.; Gillner, Danuta M.; Fan, Yao; Holz, Richard C.; Joachimiak, Andrzej

2010-01-01

Biosynthesis of lysine and meso-diaminopimelic acid in bacteria provides essential components for protein synthesis and construction of the bacterial peptidoglycan cell wall. The dapE operon enzymes synthesize both meso-diaminopimelic acid and lysine and, therefore, represent a potential targets for novel antibacterials. The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase functions in a late step of the pathway and converts N-succinyl-L,L-diaminopimelic acid (L,L-SDAP) to L,L-di...

Acidity and alkalinity in mine drainage: Theoretical considerations

Science.gov (United States)

Kirby, Carl S.; Cravotta,, Charles A.

2004-01-01

Acidity, net acidity, and net alkalinity are widely used parameters for the characterization of mine drainage, but these terms are not well defined and are often misunderstood. Incorrect interpretation of acidity, alkalinity, and derivative terms can lead to inadequate treatment design or poor regulatory decisions. We briefly explain derivations of theoretical expressions of three types of alkalinities (caustic, phenolphthalein, and total) and acidities (mineral, CO2, and total). Theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined “CO2- acidity” is closely related to most standard titration methods used for mine drainage with an endpoint pH of 8.3, but it presents numerous interpretation problems, and it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/massaction approach and employing graphs for visualization, we explore the concept of principal components and how to assign acidity contributions to solution species, including aqueous complexes, commonly found in mine drainage. We define a comprehensive theoretical definition of acidity in mine drainage on the basis of aqueous speciation at the sample pH and the capacity of these species to undergo hydrolysis to pH 8.3. This definition indicates the computed acidity in milligrams per liter (mg L-1 ) as CaCO3 (based on pH and analytical concentrations of dissolved FeIII , FeII , Mn, and Al in mg L-1 ): Aciditycomputed = 50. (10(3-pH) + 3.CFeIII/55.8 + 2.CFeII/55.8 + 2.CMn/54.9 + 3.CAl/27.0) underestimates contributions from HSO4 - and H+ , but overestimates the acidity due to Fe3+. These errors tend to approximately cancel each other. We demonstrate that “net alkalinity” is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. We demonstrate that, for most mine-drainage solutions, a

Net alkalinity and net acidity 1: Theoretical considerations

Science.gov (United States)

Kirby, C.S.; Cravotta, C.A.

2005-01-01

Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

Construction of mutant glucose oxidases with increased dye-mediated dehydrogenase activity.

Science.gov (United States)

Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

2012-11-02

Mutagenesis studies on glucose oxidases (GOxs) were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe) and Aspergillus niger GOx (PDB ID; 1cf3). We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC) oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

Science.gov (United States)

Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

2012-01-01

Mutagenesis studies on glucose oxidases (GOxs) were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe) and Aspergillus niger GOx (PDB ID; 1cf3). We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC) oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor. PMID:23203056

De Novo Construction of Redox Active Proteins.

Science.gov (United States)

Moser, C C; Sheehan, M M; Ennist, N M; Kodali, G; Bialas, C; Englander, M T; Discher, B M; Dutton, P L

2016-01-01

Relatively simple principles can be used to plan and construct de novo proteins that bind redox cofactors and participate in a range of electron-transfer reactions analogous to those seen in natural oxidoreductase proteins. These designed redox proteins are called maquettes. Hydrophobic/hydrophilic binary patterning of heptad repeats of amino acids linked together in a single-chain self-assemble into 4-alpha-helix bundles. These bundles form a robust and adaptable frame for uncovering the default properties of protein embedded cofactors independent of the complexities introduced by generations of natural selection and allow us to better understand what factors can be exploited by man or nature to manipulate the physical chemical properties of these cofactors. Anchoring of redox cofactors such as hemes, light active tetrapyrroles, FeS clusters, and flavins by His and Cys residues allow cofactors to be placed at positions in which electron-tunneling rates between cofactors within or between proteins can be predicted in advance. The modularity of heptad repeat designs facilitates the construction of electron-transfer chains and novel combinations of redox cofactors and new redox cofactor assisted functions. Developing de novo designs that can support cofactor incorporation upon expression in a cell is needed to support a synthetic biology advance that integrates with natural bioenergetic pathways. © 2016 Elsevier Inc. All rights reserved.

D-Alanine-Controlled Transient Intestinal Mono-Colonization with Non-Laboratory-Adapted Commensal E. coli Strain HS.

Science.gov (United States)

Cuenca, Miguelangel; Pfister, Simona P; Buschor, Stefanie; Bayramova, Firuza; Hernandez, Sara B; Cava, Felipe; Kuru, Erkin; Van Nieuwenhze, Michael S; Brun, Yves V; Coelho, Fernanda M; Hapfelmeier, Siegfried

2016-01-01

Soon after birth the mammalian gut microbiota forms a permanent and collectively highly resilient consortium. There is currently no robust method for re-deriving an already microbially colonized individual again-germ-free. We previously developed the in vivo growth-incompetent E. coli K-12 strain HA107 that is auxotrophic for the peptidoglycan components D-alanine (D-Ala) and meso-diaminopimelic acid (Dap) and can be used to transiently associate germ-free animals with live bacteria, without permanent loss of germ-free status. Here we describe the translation of this experimental model from the laboratory-adapted E. coli K-12 prototype to the better gut-adapted commensal strain E. coli HS. In this genetic background it was necessary to complete the D-Ala auxotrophy phenotype by additional knockout of the hypothetical third alanine racemase metC. Cells of the resulting fully auxotrophic strain assembled a peptidoglycan cell wall of normal composition, as long as provided with D-Ala and Dap in the medium, but could not proliferate a single time after D-Ala/Dap removal. Yet, unsupplemented bacteria remained active and were able to complete their cell cycle with fully sustained motility until immediately before autolytic death. Also in vivo, the transiently colonizing bacteria retained their ability to stimulate a live-bacteria-specific intestinal Immunoglobulin (Ig)A response. Full D-Ala auxotrophy enabled rapid recovery to again-germ-free status. E. coli HS has emerged from human studies and genomic analyses as a paradigm of benign intestinal commensal E. coli strains. Its reversibly colonizing derivative may provide a versatile research tool for mucosal bacterial conditioning or compound delivery without permanent colonization.

Tank Operations Contract Construction Management Methodology. Utilizing The Agency Method Of Construction Management To Safely And Effectively Complete Nuclear Construction Work

International Nuclear Information System (INIS)

Leso, K.F.; Hamilton, H.M.; Farner, M.; Heath, T.

2010-01-01

Washington River Protection Solutions, LLC (WRPS) has faced significant project management challenges in managing Davis-Bacon construction work that meets contractually required small business goals. The unique challenge is to provide contracting opportunities to multiple small business construction subcontractors while performing high hazard work in a safe and productive manner. Previous to the Washington River Protection Solutions, LLC contract, Construction work at the Hanford Tank Farms was contracted to large companies, while current Department of Energy (DOE) Contracts typically emphasize small business awards. As an integral part of Nuclear Project Management at Hanford Tank Farms, construction involves removal of old equipment and structures and installation of new infrastructure to support waste retrieval and waste feed delivery to the Waste Treatment Plant. Utilizing the optimum construction approach ensures that the contractors responsible for this work are successful in meeting safety, quality, cost and schedule objectives while working in a very hazardous environment. This paper describes the successful transition from a traditional project delivery method that utilized a large business general contractor and subcontractors to a new project construction management model that is more oriented to small businesses. Construction has selected the Agency Construction Management Method. This method was implemented in the first quarter of Fiscal Year (FY) 2009, where Construction Management is performed by substantially home office resources from the URS Northwest Office in Richland, Washington. The Agency Method has allowed WRPS to provide proven Construction Managers and Field Leads to mentor and direct small business contractors, thus providing expertise and assurance of a successful project. Construction execution contracts are subcontracted directly by WRPS to small or disadvantaged contractors that are mentored and supported by DRS personnel. Each small

TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY UTILIZING THE AGENCY METHOD OF CONSTRUCTION MANAGEMENT TO SAFELY AND EFFECTIVELY COMPLETE NUCLEAR CONSTRUCTION WORK

Energy Technology Data Exchange (ETDEWEB)

LESO KF; HAMILTON HM; FARNER M; HEATH T

2010-01-14

Washington River Protection Solutions, LLC (WRPS) has faced significant project management challenges in managing Davis-Bacon construction work that meets contractually required small business goals. The unique challenge is to provide contracting opportunities to multiple small business construction subcontractors while performing high hazard work in a safe and productive manner. Previous to the Washington River Protection Solutions, LLC contract, Construction work at the Hanford Tank Farms was contracted to large companies, while current Department of Energy (DOE) Contracts typically emphasize small business awards. As an integral part of Nuclear Project Management at Hanford Tank Farms, construction involves removal of old equipment and structures and installation of new infrastructure to support waste retrieval and waste feed delivery to the Waste Treatment Plant. Utilizing the optimum construction approach ensures that the contractors responsible for this work are successful in meeting safety, quality, cost and schedule objectives while working in a very hazardous environment. This paper describes the successful transition from a traditional project delivery method that utilized a large business general contractor and subcontractors to a new project construction management model that is more oriented to small businesses. Construction has selected the Agency Construction Management Method. This method was implemented in the first quarter of Fiscal Year (FY) 2009, where Construction Management is performed by substantially home office resources from the URS Northwest Office in Richland, Washington. The Agency Method has allowed WRPS to provide proven Construction Managers and Field Leads to mentor and direct small business contractors, thus providing expertise and assurance of a successful project. Construction execution contracts are subcontracted directly by WRPS to small or disadvantaged contractors that are mentored and supported by DRS personnel. Each small

Pharmaceutical removal in tropical subsurface flow constructed wetlands at varying hydraulic loading rates.

Science.gov (United States)

Zhang, Dong Qing; Gersberg, Richard M; Hua, Tao; Zhu, Junfei; Tuan, Nguyen Anh; Tan, Soon Keat

2012-04-01

Determining the fate of emerging organic contaminants in an aquatic ecosystem is important for developing constructed wetlands (CWs) treatment technology. Experiments were carried out in subsurface flow CWs in Singapore to evaluate the fate and transport of eight pharmaceutical compounds. The CW system included three parallel horizontal subsurface flow CWs and three parallel unplanted beds fed continuously with synthetic wastewater at different hydraulic retention times (HRTs). The findings of the tests at 2-6 d HRTs showed that the pharmaceuticals could be categorized as (i) efficiently removed compounds with removal higher than 85% (ketoprofen and salicylic acid); (ii) moderately removed compounds with removal efficiencies between 50% and 85% (naproxen, ibuprofen and caffeine); and (iii) poorly removed compounds with efficiency rate lower than 50% (carbamazepine, diclofenac, and clofibric acid). Except for carbamazepine and salicylic acid, removal efficiencies of the selected pharmaceuticals showed significant (pcaffeine, ketoprofen and clofibric acid were found to follow first order decay kinetics with decay constants higher in the planted beds than the unplanted beds. Correlations between pharmaceutical removal efficiencies and log K(ow) were not significant (p>0.05), implying that their removal is not well related to the compound's hydrophobicity. Copyright © 2011 Elsevier Ltd. All rights reserved.

Copper coordination polymers constructed from thiazole-5-carboxylic acid: Synthesis, crystal structures, and structural transformation

Energy Technology Data Exchange (ETDEWEB)

Meundaeng, Natthaya; Rujiwatra, Apinpus [Department of Chemistry, Faculty of Science, Chiang Mai University, Chiang Mai 50200 (Thailand); Prior, Timothy J., E-mail: t.prior@hull.ac.uk [Chemistry, University of Hull, Kingston upon Hull HU6 7RX (United Kingdom)

2017-01-15

We have successfully prepared crystals of thiazole-5-carboxylic acid (5-Htza) (L) and three new thiazole-5-carboxylate-based Cu{sup 2+} coordination polymers with different dimensionality, namely, 1D [Cu{sub 2}(5-tza){sub 2}(1,10-phenanthroline){sub 2}(NO{sub 3}){sub 2}] (1), 2D [Cu(5-tza){sub 2}(MeOH){sub 2}] (2), and 3D [Cu(5-tza){sub 2}]·H{sub 2}O (3). These have been characterized by single crystal X-ray diffraction and thermogravimetry. Interestingly, the 2D network structure of 2 can directly transform into the 3D framework of 3 upon removal of methanol molecules at room temperature. 2 can also undergo structural transformation to produce the same 2D network present in the known [Cu(5-tza){sub 2}]·1.5H{sub 2}O upon heat treatment for 2 h. This 2D network can adsorb water and convert to 3 upon exposure to air. - Highlights: • Rare examples of coordination polymers of thiazole-5-carboxylic acid were prepared. • Non-covalent interactions play a key role on the assembly of the complexes in solid state. • Structural transformation of a 2D framework to a 3D upon removal of methanol is observed.

Establishment of a new method to quantitatively evaluate hyphal fusion ability in Aspergillus oryzae.

Science.gov (United States)

Tsukasaki, Wakako; Maruyama, Jun-Ichi; Kitamoto, Katsuhiko

2014-01-01

Hyphal fusion is involved in the formation of an interconnected colony in filamentous fungi, and it is the first process in sexual/parasexual reproduction. However, it was difficult to evaluate hyphal fusion efficiency due to the low frequency in Aspergillus oryzae in spite of its industrial significance. Here, we established a method to quantitatively evaluate the hyphal fusion ability of A. oryzae with mixed culture of two different auxotrophic strains, where the ratio of heterokaryotic conidia growing without the auxotrophic requirements reflects the hyphal fusion efficiency. By employing this method, it was demonstrated that AoSO and AoFus3 are required for hyphal fusion, and that hyphal fusion efficiency of A. oryzae was increased by depleting nitrogen source, including large amounts of carbon source, and adjusting pH to 7.0.

Sustainable construction : towards a strategic approach to construction material management for waste reduction

OpenAIRE

Abarca Guerrero, L.; Scheublin, F.J.M.; Egmond - de Wilde De Ligny, van, E.L.C.; Lambert, A.J.D.

2008-01-01

The construction sector plays a key role in shaping and developing the built environment. It also has an undisputed and significant impact on it due to the amounts of materials extracted and produced as waste. The construction industry has emphasized to recycling construction waste (CW), however, relatively less emphasis has been paid on construction waste minimization. CW reduction can be achieved through changes in design concepts, material and construction methods selection and material ma...

Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

Science.gov (United States)

Kim, Jae Gon

2017-04-01

Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

Biochemical and functional characterization of MRA-1571 of Mycobacterium tuberculosis H37Ra and effect of its down-regulation on survival in macrophages

International Nuclear Information System (INIS)

Sharma, Rishabh; Keshari, Deepa; Singh, Kumar Sachin; Singh, Sudheer Kumar

2017-01-01

Amino acid biosynthesis has emerged as a source of new drug targets as many bacterial strains auxotrophic for amino acids fail to proliferate under in vivo conditions. Branch chain amino acids (BCAAs) are important for Mycobacterium tuberculosis (Mtb) survival and strains deficient in their biosynthesis were attenuated for growth in mice. Threonine dehydratase (IlvA) is a pyridoxal-5-phosphate (PLP) dependent enzyme that catalyzes the first step in isoleucine biosynthesis. The MRA-1571 of Mycobacterium tuberculosis H37Ra (Mtb-Ra), annotated to be coding for IlvA, was cloned, expressed and purified. Purified protein was subsequently used for developing enzyme assay and to study its biochemical properties. Also, E. coli BL21 (DE3) IlvA knockout (E. coli-ΔilvA) was developed and genetically complemented with Mtb-Ra ilvA expression construct (pET32a-ilvA) to make complemented E. coli strain (E. coli-ΔilvA + pET32a-ilvA). The E. coli-ΔilvA showed growth failure in minimal medium but growth restoration was observed in E. coli-ΔilvA + pET32a-ilvA. E. coli-ΔilvA growth was also restored in the presence of isoleucine. The IlvA localization studies detected its distribution in cell wall and membrane fractions with relatively minor presence in cytosolic fraction. Maximum IlvA expression was observed at 72 h in wild-type (WT) Mtb-Ra infecting macrophages. Also, Mtb-Ra IlvA knockdown (KD) showed reduced survival in macrophages compared to WT and complemented strain (KDC). - Highlights: • Mtb-Ra gene MRA-1571 codes for a functional threonine dehydratase (IlvA). • IlvA is pyridoxal 5’-phosphate dependent and is inhibited by isoleucine. • E. coli IlvA knockout growth can be supplemented by isoleucine or by Mtb-Ra IlvA. • The enzyme is primarily localized in cell wall and membrane fractions. • IlvA knockdown Mtb-Ra shows reduced growth in macrophages.

Development of the Multiple Gene Knockout System with One-Step PCR in Thermoacidophilic Crenarchaeon Sulfolobus acidocaldarius

Directory of Open Access Journals (Sweden)

Shoji Suzuki

2017-01-01

Full Text Available Multiple gene knockout systems developed in the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius are powerful genetic tools. However, plasmid construction typically requires several steps. Alternatively, PCR tailing for high-throughput gene disruption was also developed in S. acidocaldarius, but repeated gene knockout based on PCR tailing has been limited due to lack of a genetic marker system. In this study, we demonstrated efficient homologous recombination frequency (2.8 × 104 ± 6.9 × 103 colonies/μg DNA by optimizing the transformation conditions. This optimized protocol allowed to develop reliable gene knockout via double crossover using short homologous arms and to establish the multiple gene knockout system with one-step PCR (MONSTER. In the MONSTER, a multiple gene knockout cassette was simply and rapidly constructed by one-step PCR without plasmid construction, and the PCR product can be immediately used for target gene deletion. As an example of the applications of this strategy, we successfully made a DNA photolyase- (phr- and arginine decarboxylase- (argD- deficient strain of S. acidocaldarius. In addition, an agmatine selection system consisting of an agmatine-auxotrophic strain and argD marker was also established. The MONSTER provides an alternative strategy that enables the very simple construction of multiple gene knockout cassettes for genetic studies in S. acidocaldarius.

Beyond Design: The Importance of Construction and Post-Construction Phases in Green Developments

Directory of Open Access Journals (Sweden)

Mark Hostetler

2010-04-01

Full Text Available Green developments are becoming a popular land use planning concept that attempts to accommodate growth while minimizing impacts on natural resources. Various policies encourage conservation designs that usually translate into the clustering of homes and the conservation of some percentage of open space. However, the success of a design is determined by what happens during the construction and post-construction phases of a subdivision project. These two phases are often ignored in land use planning and given only minimal attention by built environment professionals. As a result, green developments may not be functioning as originally intended. This essay discusses the importance of construction and post-construction and a way forward to create functional, sustainable communities. Construction activities and decisions, such as impacts from earthwork machines, improper protection of conserved open spaces and trees, the choice of plants used for yards and common areas, and the storage of construction material all can lead to severe impacts on natural areas both within and surrounding a development site. During post-construction, a variety of improper management practices by homeowners can compromise the sustainability of a development. Developers and associated environmental consultant teams could implement approaches that would engage contractors and residents, such as environmental construction covenants and the installment of a neighborhood, environmental education program. To increase the adoption of relevant construction and post-construction practices, appropriate policies need to be created. However, the shift will only occur once the planning and built environment community acknowledges that design is only the first step towards sustainability. Academic design studios and continuing education courses can help with this culture shift by including construction and post-construction considerations within their curriculum.

Sulfate and acid resistant concrete and mortar

Science.gov (United States)

Liskowitz, John W.; Wecharatana, Methi; Jaturapitakkul, Chai; Cerkanowicz, deceased, Anthony E.

1998-01-01

The present invention relates to concrete, mortar and other hardenable mixtures comprising cement and fly ash for use in construction and other applications, which hardenable mixtures demonstrate significant levels of acid and sulfate resistance while maintaining acceptable compressive strength properties. The acid and sulfate hardenable mixtures of the invention containing fly ash comprise cementitious materials and a fine aggregate. The cementitous materials may comprise fly ash as well as cement. The fine aggregate may comprise fly ash as well as sand. The total amount of fly ash in the hardenable mixture ranges from about 60% to about 120% of the total amount of cement, by weight, whether the fly ash is included as a cementious material, fine aggregate, or an additive, or any combination of the foregoing. In specific examples, mortar containing 50% fly ash and 50% cement in cementitious materials demonstrated superior properties of corrosion resistance.

Methionine sulphoxide reductases revisited: free methionine as a primary target of H2O2 stress in auxotrophic fission yeast

OpenAIRE

García Santamarina, Sarela, 1978-; Boronat i Llop, Susanna, 1965-; Ayté del Olmo, José; Hidalgo Hernando, Elena

2013-01-01

Amino acid methionine can suffer reversible oxidation to sulphoxide and further irreversible over-oxidation to methionine sulphone. As part of the cellular antioxidant scavenging activities are the methionine sulphoxide reductases (Msrs), with a reported role in methionine sulphoxide reduction, both free and in proteins. Three families of Msrs have been described, but the fission yeast genome only includes one representative for two of these families: MsrA/Mxr1 and MsrB/Mxr2. We have investig...

Trypanocidal Effect of Isotretinoin through the Inhibition of Polyamine and Amino Acid Transporters in Trypanosoma cruzi.

Directory of Open Access Journals (Sweden)

Chantal Reigada

2017-03-01

Full Text Available Polyamines are essential compounds to all living organisms and in the specific case of Trypanosoma cruzi, the causative agent of Chagas disease, they are exclusively obtained through transport processes since this parasite is auxotrophic for polyamines. Previous works reported that retinol acetate inhibits Leishmania growth and decreases its intracellular polyamine concentration. The present work describes a combined strategy of drug repositioning by virtual screening followed by in vitro assays to find drugs able to inhibit TcPAT12, the only polyamine transporter described in T. cruzi. After a screening of 3000 FDA-approved drugs, 7 retinoids with medical use were retrieved and used for molecular docking assays with TcPAT12. From the docked molecules, isotretinoin, a well-known drug used for acne treatment, showed the best interaction score with TcPAT12 and was selected for further in vitro studies. Isotretinoin inhibited the polyamine transport, as well as other amino acid transporters from the same protein family (TcAAAP, with calculated IC50 values in the range of 4.6-10.3 μM. It also showed a strong inhibition of trypomastigote burst from infected cells, with calculated IC50 of 130 nM (SI = 920 being significantly less effective on the epimastigote stage (IC50 = 30.6 μM. The effect of isotretinoin on the parasites plasma membrane permeability and on mammalian cell viability was tested, and no change was observed. Autophagosomes and apoptotic bodies were detected as part of the mechanisms of isotretinoin-induced death indicating that the inhibition of transporters by isotretinoin causes nutrient starvation that triggers autophagic and apoptotic processes. In conclusion, isotretinoin is a promising trypanocidal drug since it is a multi-target inhibitor of essential metabolites transporters, in addition to being an FDA-approved drug largely used in humans, which could reduce significantly the requirements for its possible application in the

Integrated electrochemical gluconic acid biosensor based on self-assembled monolayer-modified gold electrodes. Application to the analysis of gluconic acid in musts and wines.

Science.gov (United States)

Campuzano, S; Gamella, M; Serra, B; Reviejo, A J; Pingarrón, J M

2007-03-21

An integrated amperometric gluconic acid biosensor constructed using a gold electrode (AuE) modified with a self-assembled monolayer (SAM) of 3-mercaptopropionic acid (MPA) on which gluconate dehydrogenase (GADH, 0.84 U) and the mediator tetrathiafulvalene (TTF, 1.5 micromol) were coimmobilized by covering the electrode surface with a dialysis membrane is reported. The working conditions selected were Eapp=+0.15 V and 25+/-1 degrees C. The useful lifetime of one single TTF-GADH-MPA-AuE was surprisingly long. After 53 days of continuous use, the biosensor exhibited 86% of the original sensitivity. A linear calibration plot was obtained for gluconic acid over the 6.0x10(-7) to 2.0x10(-5) M concentration range, with a limit of detection of 1.9x10(-7) M. The effect of potential interferents (glucose, fructose, galactose, arabinose, and tartaric, citric, malic, ascorbic, gallic, and caffeic acids) on the biosensor response was evaluated. The behavior of the biosensor in a flow-injection system in connection with amperometric detection was tested. The analytical usefulness of the biosensor was evaluated by determining gluconic acid in wine and must samples, and the results obtained were validated by comparison with those provided by using a commercial enzyme test kit.

Construction time of PWRs

International Nuclear Information System (INIS)

Moreira, João M.L.; Gallinaro, Bruno; Carajilescov, Pedro

2013-01-01

The construction time of PWRs is studied considering published data about nuclear power plants in the world. For the 268 PWRs in operation in 2010, the mode of the construction time distribution is around 5–6 years, and 80% of the plants were built in less than 120 months. To circumvent the problem of comparing plants with different size we normalized the construction time to plants with 1 GW. We restricted the analysis to 201 PWRs which suffered less from external factors that were beyond the control of the management from 1965 to 2010. The results showed that the normalized construction time did not increase over the years and nor with the plants’ gross power level. The learning rate of the industry regarding normalized construction times showed a reduction with 95% confidence level of about 0.56±0.07 months for each 10 GW of installed capacity. Over the years the normalized construction time decreased and became more predictable. The data showed that countries with more centralized regulatory, construction and operation environments were able to build PWRs in shorter times. Countries less experienced with the nuclear technology built PWRs in longer times. - Highlights: ► The construction time of PWRs is analyzed based on historical data. ► Different factors affecting construction time are considered in the analyses. ► The normalized construction time of PWRs decreased with time and gross power level. ► Countries with more centralized institutions built PWRs more quickly

Two new coordination polymers constructed by naphthalene-1,4-dicarboxylic acid and 2,4-diamino-6-methyl-triazine

Energy Technology Data Exchange (ETDEWEB)

Li, Yamin, E-mail: liyamin@henu.edu.cn [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Xiao, Changyu [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China); Zhang, Xudong [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Xu, Yanhui [Department of Medical Imaging, Bethune Medical Non-Commissioned Officer' s, College, Shijiazhuang, Hebei 050081 (China); Li, Junrui; Lun, Huijie; Chen, Qi [Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004 (China)

2013-08-15

Two new transition metal coordination complexes, ([MnO(nda)](H{sub 2}dmt)(H{sub 2}O)){sub n} (1), [Ag{sub 5}(nda){sub 2.5}(dmt)]{sub n} (2), (H{sub 2}nda=naphthalene-1,4-dicarboxylic acid, dmt=2,4-diamine-6-methyl-1,3,5-triazine) have been hydrothermally synthesized by the reactions of H{sub 2}nda and dmt with the homologous MnCl{sub 2}·4H{sub 2}O and AgNO{sub 3}, respectively, and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis, thermogravimetric analysis (TGA). The compound 1 exhibits a 3D network comprising 1D metal chain (MnO(CO{sub 2}){sub 2}){sub n} connected by the ligand nda{sup 2−}, featuring a four-connected uninodal diamond -like topology. In compound 2, it is firstly observed that decanuclear silver units as secondary building units to construct 3D network by the ligands dmt and nda{sup 2−}, with a rare 2-nodal (3,8)-connected tfz-d topology ((4{sup 3}){sub 2}(4{sup 6}.6{sup 18}.8{sup 4})). The interactions within each Mn(II)—Mn(II) pair of compound 1 are antiferromagnetic (g=2.07, J=−1.42(1) cm{sup −1}, zj′=−0.73(2) cm{sup −1}). In addition, compound 2 exhibits photoluminescent property at about 472 nm (λ{sub ex}=394 nm). - Graphical abstract: Two new transition metal coordination complexes 1–2 have been hydrothermally synthesized and characterized by single-crystal X-ray diffraction, IR spectra, elemental analysis thermogravimetric analysis (TGA). Highlights: • The compound 1 exhibits a 3D network with four-connected uninodal diamond-like topology. • The first 3D network of 2 with a rare tfz-d topology consists of decanuclear silver clusters as secondary building units. • The magnetic measurement indicates the compound 1 shows antiferromagnetic interactions. • The photoluminescent property of 2 has been measured.

Chemical construction and structural permutation of potent cytotoxin polytheonamide B: discovery of artificial peptides with distinct functions.

Science.gov (United States)

Itoh, Hiroaki; Inoue, Masayuki

2013-07-16

Polytheonamide B (1), isolated from the marine sponge Theonella swinhoei, is a posttranslationally modified ribosomal peptide (MW 5030 Da) that displays extraordinary cytotoxicity. Among its 48 amino acid residues, this peptide includes a variety D- and L-amino acids that do not occur in proteins, and the chiralities of these amino acids alternate in sequence. These structural features induce the formation of a stable β6.3-helix, giving rise to a tubular structure of over 4 nm in length. In the biological setting, this fold is believed to transport cations across the lipid bilayer through a pore, thereby acting as an ion channel. In this Account, we discuss the construction and structural permutations of this potent cytotoxin. First we describe the 161-step chemical construction of this unusual peptide 1. By developing a synthetic route to 1, we established the chemical basis for subsequent SAR studies to pinpoint the proteinogenic and nonproteinogenic building blocks within the molecule that confer its toxicity and channel function. Using fully synthetic 1, we generated seven analogues with point mutations, and studies of their activity revealed the importance of the N-terminal moiety. Next, we simplified the structure of 1 by substituting six amino acid residues of 1 to design a more synthetically accessible analogue 9. This dansylated polytheonamide mimic 9 was synthesized in 127 total steps, and we evaluated its function to show that it can emulate the toxic and ion channel activities of 1 despite its multiple structural modifications. Finally, we applied a highly automated synthetic route to 48-mer 9 to generate 13 substructures of 27-39-mers. The 37-mer 12 exhibited nanomolar level toxicity through a potentially distinct mode of action from 1 and 9. The SAR studies of polytheonamide B and the 21 artificial analogues have deepened our understanding of the precise structural requirements for the biological functions of 1. They have also led to the discovery of

78 FR 20029 - Castor Oil, Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance...

Science.gov (United States)

2013-04-03

..., Polymer With Adipic Acid, Linoleic Acid, Oleic Acid and Ricinoleic Acid; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of castor oil, polymer with adipic acid, linoleic acid... pesticide formulation. Advance Polymer Technology submitted a petition to EPA under the Federal Food, Drug...

Efficient fermentation of xylose to ethanol at high formic acid concentrations by metabolically engineered Saccharomyces cerevisiae

Energy Technology Data Exchange (ETDEWEB)

Hasunuma, Tomohisa; Yoshimura, Kazuya; Matsuda, Fumio [Kobe Univ., Hyogo (Japan). Organization of Advanced Science and Technology; Sung, Kyung-mo; Sanda, Tomoya; Kondo, Akihiko [Kobe Univ., Hyogo (Japan). Dept. of Chemical Science and Engineering

2011-05-15

Recombinant yeast strains highly tolerant to formic acid during xylose fermentation were constructed. Microarray analysis of xylose-fermenting Saccharomyces cerevisiae strain overexpressing endogenous xylulokinase in addition to xylose reductase and xylitol dehydrogenase from Pichia stipitis revealed that upregulation of formate dehydrogenase genes (FDH1 and FDH2) was one of the most prominent transcriptional events against excess formic acid. The quantification of formic acid in medium indicated that the innate activity of FDH was too weak to detoxify formic acid. To reinforce the capability for formic acid breakdown, the FDH1 gene was additionally overexpressed in the xylose-metabolizing recombinant yeast. This modification allowed the yeast to rapidly decompose excess formic acid. The yield and final ethanol concentration in the presence of 20 mM formic acid is as essentially same as that of control. The fermentation profile also indicated that the production of xylitol and glycerol, major by-products in xylose fermentation, was not affected by the upregulation of FDH activity. (orig.)

Superstring construction

CERN Document Server

1989-01-01

The book includes a selection of papers on the construction of superstring theories, mainly written during the years 1984-1987. It covers ten-dimensional supersymmetric and non-supersymmetric strings, four-dimensional heterotic strings and four-dimensional type-II strings. An introduction to more recent developments in conformal field theory in relation to string construction is provided.

Concrete construction engineering handbook

CERN Document Server

Nawy, Edward G

2008-01-01

Provides coverage of concrete construction engineering and technology. This work features discussions focusing on: the advances in engineered concrete materials; reinforced concrete construction; specialized construction techniques; and, design recommendations for high performance.

Tank Operations Contract Construction Management Methodology. Utilizing The Agency Method Of Construction Management

International Nuclear Information System (INIS)

Lesko, K.F.; Berriochoa, M.V.

2010-01-01

Washington River Protection Solutions, LLC (WRPS) has faced significant project management challenges in managing Davis-Bacon construction work that meets contractually required small business goals. The unique challenge is to provide contracting opportunities to multiple small business constructioin subcontractors while performing high hazard work in a safe and productive manner. Previous to the WRPS contract, construction work at the Hanford Tank Farms was contracted to large companies, while current Department of Energy (DOE) Contracts typically emphasize small business awards. As an integral part of Nuclear Project Management at Hanford Tank Farms, construction involves removal of old equipment and structures and installation of new infrastructure to support waste retrieval and waste feed delivery to the Waste Treatment Plant. Utilizing the optimum construction approach ensures that the contractors responsible for this work are successful in meeting safety, quality, cost and schedule objectives while working in a very hazardous environment. This paper descirbes the successful transition from a traditional project delivery method that utilized a large business general contractor and subcontractors to a new project construction management model that is more oriented to small businesses. Construction has selected the Agency Construction Management Method (John E Schaufelberger, Len Holm, 'Management of Construction Projects, A Constructor's Perspective', University of Washington, Prentice Hall 2002). This method was implemented in the first quarter of Fiscal Year 2009 (FY2009), where Construction Management is performed by substantially home office resources from the URS Northwest Office in Richland, Washington. The Agency Method has allowed WRPS to provide proven Construction Managers and Field Leads to mentor and direct small business contractors, thus providing expertise and assurance of a successful project. Construction execution contracts are subcontracted

TANK OPERATIONS CONTRACT CONSTRUCTION MANAGEMENT METHODOLOGY UTILIZING THE AGENCY METHOD OF CONSTRUCTION MANAGEMENT

Energy Technology Data Exchange (ETDEWEB)

LESKO KF; BERRIOCHOA MV

2010-02-26

Washington River Protection Solutions, LLC (WRPS) has faced significant project management challenges in managing Davis-Bacon construction work that meets contractually required small business goals. The unique challenge is to provide contracting opportunities to multiple small business constructioin subcontractors while performing high hazard work in a safe and productive manner. Previous to the WRPS contract, construction work at the Hanford Tank Farms was contracted to large companies, while current Department of Energy (DOE) Contracts typically emphasize small business awards. As an integral part of Nuclear Project Management at Hanford Tank Farms, construction involves removal of old equipment and structures and installation of new infrastructure to support waste retrieval and waste feed delivery to the Waste Treatment Plant. Utilizing the optimum construction approach ensures that the contractors responsible for this work are successful in meeting safety, quality, cost and schedule objectives while working in a very hazardous environment. This paper descirbes the successful transition from a traditional project delivery method that utilized a large business general contractor and subcontractors to a new project construction management model that is more oriented to small businesses. Construction has selected the Agency Construction Management Method (John E Schaufelberger, Len Holm, "Management of Construction Projects, A Constructor's Perspective", University of Washington, Prentice Hall 2002). This method was implemented in the first quarter of Fiscal Year 2009 (FY2009), where Construction Management is performed by substantially home office resources from the URS Northwest Office in Richland, Washington. The Agency Method has allowed WRPS to provide proven Construction Managers and Field Leads to mentor and direct small business contractors, thus providing expertise and assurance of a successful project. Construction execution contracts are

Highly efficient residue-selective labeling with isotope-labeled Ile, Leu, and Val using a new auxotrophic E. coli strain

International Nuclear Information System (INIS)

Miyanoiri, Yohei; Ishida, Yojiro; Takeda, Mitsuhiro; Terauchi, Tsutomu; Inouye, Masayori; Kainosho, Masatsune

2016-01-01

We recently developed a practical protocol for preparing proteins bearing stereo-selectively 13 C-methyl labeled leucines and valines, instead of the commonly used 13 C-methyl labeled precursors for these amino acids, by E. coli cellular expression. Using this protocol, proteins with any combinations of isotope-labeled or unlabeled Leu and Val residues were prepared, including some that could not be prepared by the precursor methods. However, there is still room for improvement in the labeling efficiencies for Val residues, using the methods with labeled precursors or Val itself. This is due to the fact that the biosynthesis of Val could not be sufficiently suppressed, even by the addition of large amounts of Val or its precursors. In this study, we completely solved this problem by using a mutant strain derived from E. coli BL21(DE3), in which the metabolic pathways depending on two enzymes, dihydroxy acid dehydratase and β-isopropylmalate dehydrogenase, are completely aborted by deleting the ilvD and leuB genes, which respectively encode these enzymes. The ΔilvD E. coli mutant terminates the conversion from α,β-dihydroxyisovalerate to α-ketoisovalerate, and the conversion from α,β-dihydroxy-α-methylvalerate to α-keto-β-methylvalerate, which produce the preceding precursors for Val and Ile, respectively. By the further deletion of the leuB gene, the conversion from Val to Leu was also fully terminated. Taking advantage of the double-deletion mutant, ΔilvDΔleuB E. coli BL21(DE3), an efficient and residue-selective labeling method with various isotope-labeled Ile, Leu, and Val residues was established.

Highly efficient residue-selective labeling with isotope-labeled Ile, Leu, and Val using a new auxotrophic E. coli strain

Energy Technology Data Exchange (ETDEWEB)

Miyanoiri, Yohei [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan); Ishida, Yojiro [Rutgers University-Robert Wood Johnson Medical School, Center for Advanced Biotechnology and Medicine (United States); Takeda, Mitsuhiro [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan); Terauchi, Tsutomu [Tokyo Metropolitan University, Graduate School of Science and Engineering (Japan); Inouye, Masayori [Rutgers University-Robert Wood Johnson Medical School, Center for Advanced Biotechnology and Medicine (United States); Kainosho, Masatsune, E-mail: kainosho@tmu.ac.jp [Nagoya University, Structural Biology Research Center, Graduate School of Science (Japan)

2016-06-15

We recently developed a practical protocol for preparing proteins bearing stereo-selectively {sup 13}C-methyl labeled leucines and valines, instead of the commonly used {sup 13}C-methyl labeled precursors for these amino acids, by E. coli cellular expression. Using this protocol, proteins with any combinations of isotope-labeled or unlabeled Leu and Val residues were prepared, including some that could not be prepared by the precursor methods. However, there is still room for improvement in the labeling efficiencies for Val residues, using the methods with labeled precursors or Val itself. This is due to the fact that the biosynthesis of Val could not be sufficiently suppressed, even by the addition of large amounts of Val or its precursors. In this study, we completely solved this problem by using a mutant strain derived from E. coli BL21(DE3), in which the metabolic pathways depending on two enzymes, dihydroxy acid dehydratase and β-isopropylmalate dehydrogenase, are completely aborted by deleting the ilvD and leuB genes, which respectively encode these enzymes. The ΔilvD E. coli mutant terminates the conversion from α,β-dihydroxyisovalerate to α-ketoisovalerate, and the conversion from α,β-dihydroxy-α-methylvalerate to α-keto-β-methylvalerate, which produce the preceding precursors for Val and Ile, respectively. By the further deletion of the leuB gene, the conversion from Val to Leu was also fully terminated. Taking advantage of the double-deletion mutant, ΔilvDΔleuB E. coli BL21(DE3), an efficient and residue-selective labeling method with various isotope-labeled Ile, Leu, and Val residues was established.

Construction labor productivity during nuclear power plant construction

International Nuclear Information System (INIS)

Murray, W.B.

1980-01-01

This paper discusses the three different types of productivity programs used at the Wm. H. Zimmer Nuclear Power Station construction site. The Standard Cost Estimate as Productivity Measurement compares actual units installed to estimated units. The Manpower and Equipment Utilization Study measures the present utilization level of the construction work force, identifies opportunities for productivity improvement, and establishes a data base against which future improvements could be made. The special productivity program is a specialized and detailed study of first line supervision. Productivity is defined as the degree of efficiency attained in the use of labor, professional and management skills and knowledge, materials and equipment, and time and money to produce an end result. It is concluded that a more consistent system of productivity measurements needs to be developed and promoted for general use in the construction industry

Seq2Logo: a method for construction and visualization of amino acid binding motifs and sequence profiles including sequence weighting, pseudo counts and two-sided representation of amino acid enrichment and depletion

DEFF Research Database (Denmark)

Thomsen, Martin Christen Frølund; Nielsen, Morten

2012-01-01

Seq2Logo is a web-based sequence logo generator. Sequence logos are a graphical representation of the information content stored in a multiple sequence alignment (MSA) and provide a compact and highly intuitive representation of the position-specific amino acid composition of binding motifs, active...... related to amino acid enrichment and depletion. Besides allowing input in the format of peptides and MSA, Seq2Logo accepts input as Blast sequence profiles, providing easy access for non-expert end-users to characterize and identify functionally conserved/variable amino acids in any given protein...... sites, etc. in biological sequences. Accurate generation of sequence logos is often compromised by sequence redundancy and low number of observations. Moreover, most methods available for sequence logo generation focus on displaying the position-specific enrichment of amino acids, discarding the equally...

Anatomic Mesenchymal Stem Cell-Based Engineered Cartilage Constructs for Biologic Total Joint Replacement

Science.gov (United States)

Saxena, Vishal; Kim, Minwook; Keah, Niobra M.; Neuwirth, Alexander L.; Stoeckl, Brendan D.; Bickard, Kevin; Restle, David J.; Salowe, Rebecca; Wang, Margaret Ye; Steinberg, David R.

2016-01-01

Cartilage has a poor healing response, and few viable options exist for repair of extensive damage. Hyaluronic acid (HA) hydrogels seeded with mesenchymal stem cells (MSCs) polymerized through UV crosslinking can generate functional tissue, but this crosslinking is not compatible with indirect rapid prototyping utilizing opaque anatomic molds. Methacrylate-modified polymers can also be chemically crosslinked in a cytocompatible manner using ammonium persulfate (APS) and N,N,N′,N′-tetramethylethylenediamine (TEMED). The objectives of this study were to (1) compare APS/TEMED crosslinking with UV crosslinking in terms of functional maturation of MSC-seeded HA hydrogels; (2) generate an anatomic mold of a complex joint surface through rapid prototyping; and (3) grow anatomic MSC-seeded HA hydrogel constructs using this alternative crosslinking method. Juvenile bovine MSCs were suspended in methacrylated HA (MeHA) and crosslinked either through UV polymerization or chemically with APS/TEMED to generate cylindrical constructs. Minipig porcine femoral heads were imaged using microCT, and anatomic negative molds were generated by three-dimensional printing using fused deposition modeling. Molded HA constructs were produced using the APS/TEMED method. All constructs were cultured for up to 12 weeks in a chemically defined medium supplemented with TGF-β3 and characterized by mechanical testing, biochemical assays, and histologic analysis. Both UV- and APS/TEMED-polymerized constructs showed increasing mechanical properties and robust proteoglycan and collagen deposition over time. At 12 weeks, APS/TEMED-polymerized constructs had higher equilibrium and dynamic moduli than UV-polymerized constructs, with no differences in proteoglycan or collagen content. Molded HA constructs retained their hemispherical shape in culture and demonstrated increasing mechanical properties and proteoglycan and collagen deposition, especially at the edges compared to the center of these

Assessing problem-solving skills in construction education with the virtual construction simulator

Science.gov (United States)

Castronovo, Fadi

The ability to solve complex problems is an essential skill that a construction and project manager must possess when entering the architectural, engineering, and construction industry. Such ability requires a mixture of problem-solving skills, ranging from lower to higher order thinking skills, composed of cognitive and metacognitive processes. These skills include the ability to develop and evaluate construction plans and manage the execution of such plans. However, in a typical construction program, introducing students to such complex problems can be a challenge, and most commonly the learner is presented with only part of a complex problem. To support this challenge, the traditional methodology of delivering design, engineering, and construction instruction has been going through a technological revolution, due to the rise of computer-based technology. For example, in construction classrooms, and other disciplines, simulations and educational games are being utilized to support the development of problem-solving skills. Previous engineering education research has illustrated the high potential that simulations and educational games have in engaging in lower and higher order thinking skills. Such research illustrated their capacity to support the development of problem-solving skills. This research presents evidence supporting the theory that educational simulation games can help with the learning and retention of transferable problem-solving skills, which are necessary to solve complex construction problems. The educational simulation game employed in this study is the Virtual Construction Simulator (VCS). The VCS is a game developed to provide students in an engaging learning activity that simulates the planning and managing phases of a construction project. Assessment of the third iteration of the VCS(3) game has shown pedagogical value in promoting students' motivation and a basic understanding of construction concepts. To further evaluate the benefits on

Applying lean thinking in construction

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Remon Fayek Aziz

2013-12-01

Full Text Available The productivity of the construction industry worldwide has been declining over the past 40 years. One approach for improving the situation is using lean construction. Lean construction results from the application of a new form of production management to construction. Essential features of lean construction include a clear set of objectives for the delivery process, aimed at maximizing performance for the customer at the project level, concurrent design, construction, and the application of project control throughout the life cycle of the project from design to delivery. An increasing number of construction academics and professionals have been storming the ramparts of conventional construction management in an effort to deliver better value to owners while making real profits. As a result, lean-based tools have emerged and have been successfully applied to simple and complex construction projects. In general, lean construction projects are easier to manage, safer, completed sooner, and cost less and are of better quality. Significant research remains to complete the translation to construction of lean thinking in Egypt. This research will discuss principles, methods, and implementation phases of lean construction showing the waste in construction and how it could be minimized. The Last Planner System technique, which is an important application of the lean construction concepts and methodologies and is more prevalent, proved that it could enhance the construction management practices in various aspects. Also, it is intended to develop methodology for process evaluation and define areas for improvement based on lean approach principles.

Gene transfer of Chlorella vulgaris n-3 fatty acid desaturase optimizes the fatty acid composition of human breast cancer cells

Directory of Open Access Journals (Sweden)

Meilan Xue

2012-12-01

Full Text Available Chlorella vulgaris has the gene of n-3 fatty acid desaturase (CvFad3, which can synthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs or convert n-6 to n-3 PUFAs. The objective of the present study was to examine whether the CvFad3 gene from C. vulgaris can be functionally and efficiently expressed in human breast cancer cells and whether its expression can exert a significant effect on cell fatty acid composition. We inserted the CvFad3 gene into the plasmid pEGFP-C3 to construct the eukaryotic expression vector pEGFP-C3-n-3 and to express the n-3 Fad gene in human breast cancer cells (MCF-7 cells. Transfection of MCF-7 cells with the recombinant vector resulted in a high expression of n-3 fatty acid desaturase. Lipid analysis indicated that the ratio of n-6/n-3 PUFAs was decreased from 6:1 in the control cells to about 1:1 in the cells expressing the n-3 fatty acid desaturase. Accordingly, the CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of the MCF-7 cell membrane. The expression of the CvFad3 gene can decrease cell proliferation and promote cell apoptosis. This study demonstrates that the CvFad3 gene can dramatically balance the ratio of n-6/n-3 PUFAs and may provide an effective approach to the modification of the fatty acid composition of mammalian cells, also providing a basis for potential applications of its transfer in experimental and clinical settings.

Gene transfer of Chlorella vulgaris n-3 fatty acid desaturase optimizes the fatty acid composition of human breast cancer cells

Energy Technology Data Exchange (ETDEWEB)

Xue, Meilan; Ge, Yinlin; Zhang, Jinyu [Department of Biochemistry and Molecular Biology, Medical College, Qingdao University, Qingdao Shandong (China); Wang, Qing [Affiliated Hospital of Qingdao University, Qingdao Shandong (China); Hou, Lin [Department of Biochemistry and Molecular Biology, Medical College, Qingdao University, Qingdao Shandong (China)

2012-09-14

Chlorella vulgaris has the gene of n-3 fatty acid desaturase (CvFad3), which can synthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs) or convert n-6 to n-3 PUFAs. The objective of the present study was to examine whether the CvFad3 gene from C. vulgaris can be functionally and efficiently expressed in human breast cancer cells and whether its expression can exert a significant effect on cell fatty acid composition. We inserted the CvFad3 gene into the plasmid pEGFP-C3 to construct the eukaryotic expression vector pEGFP-C3-n-3 and to express the n-3 Fad gene in human breast cancer cells (MCF-7 cells). Transfection of MCF-7 cells with the recombinant vector resulted in a high expression of n-3 fatty acid desaturase. Lipid analysis indicated that the ratio of n-6/n-3 PUFAs was decreased from 6:1 in the control cells to about 1:1 in the cells expressing the n-3 fatty acid desaturase. Accordingly, the CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of the MCF-7 cell membrane. The expression of the CvFad3 gene can decrease cell proliferation and promote cell apoptosis. This study demonstrates that the CvFad3 gene can dramatically balance the ratio of n-6/n-3 PUFAs and may provide an effective approach to the modification of the fatty acid composition of mammalian cells, also providing a basis for potential applications of its transfer in experimental and clinical settings.

Gene transfer of Chlorella vulgaris n-3 fatty acid desaturase optimizes the fatty acid composition of human breast cancer cells

International Nuclear Information System (INIS)

Xue, Meilan; Ge, Yinlin; Zhang, Jinyu; Wang, Qing; Hou, Lin

2012-01-01

Chlorella vulgaris has the gene of n-3 fatty acid desaturase (CvFad3), which can synthesize the precursor of n-3 polyunsaturated fatty acids (PUFAs) or convert n-6 to n-3 PUFAs. The objective of the present study was to examine whether the CvFad3 gene from C. vulgaris can be functionally and efficiently expressed in human breast cancer cells and whether its expression can exert a significant effect on cell fatty acid composition. We inserted the CvFad3 gene into the plasmid pEGFP-C3 to construct the eukaryotic expression vector pEGFP-C3-n-3 and to express the n-3 Fad gene in human breast cancer cells (MCF-7 cells). Transfection of MCF-7 cells with the recombinant vector resulted in a high expression of n-3 fatty acid desaturase. Lipid analysis indicated that the ratio of n-6/n-3 PUFAs was decreased from 6:1 in the control cells to about 1:1 in the cells expressing the n-3 fatty acid desaturase. Accordingly, the CvFad3 gene significantly decreased the ratio of n-6/n-3 PUFAs of the MCF-7 cell membrane. The expression of the CvFad3 gene can decrease cell proliferation and promote cell apoptosis. This study demonstrates that the CvFad3 gene can dramatically balance the ratio of n-6/n-3 PUFAs and may provide an effective approach to the modification of the fatty acid composition of mammalian cells, also providing a basis for potential applications of its transfer in experimental and clinical settings

Direct electrodeposition of gold nanotube arrays of rough and porous wall by cyclic voltammetry and its applications of simultaneous determination of ascorbic acid and uric acid

International Nuclear Information System (INIS)

Yang Guangming; Li Ling; Jiang Jinhe; Yang Yunhui

2012-01-01

Gold nanotube arrays of rough and porous wall has been synthesized by direct electrodeposition with cyclic voltammetry utilizing anodic aluminum oxide template (AAO) and polycarbonate membrane (PC) during short time (only 3 min and 2 min, respectively). The mechanism of the direct electrodeposition of gold nanotube arrays by cyclic voltammetry (CV) has been discussed. The morphological characterizations of the gold nanotube arrays have been investigated by scanning electron microscopy (SEM). A simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry (DPV) was constructed by attaching gold nanotube arrays (using AAO) onto the surface of a glassy carbon electrode (GCE). The electrochemical behavior of AA and UA at this modified electrode has been studied by CV and differential pulse voltammetry (DPV). The sensor offers an excellent response for AA and UA and the linear response range for AA and UA were 1.02 × 10 −7 –5.23 × 10 −4 mol L −1 and 1.43 × 10 −7 –4.64 × 10 −4 mol L −1 , the detection limits were 1.12 × 10 −8 mol L −1 and 2.24 × 10 −8 mol L −1 , respectively. This sensor shows good regeneration, stability and selectivity and has been used for the determination of AA and UA in real human urine and serum samples with satisfied results. - Graphical abstract: The schematic diagram of formation of Au nanotube arrays (a) and the stepwise procedure of the sensor (b). Highlights: ► Gold nanotubes array has been synthesized by cyclic voltammetry. ► The mechanism of deposition of gold nanotube has been discussed. ► A determination of ascorbic acid and uric acid was constructed by gold array. ► A satisfied determination of samples can be obtained by this sensor.

Influence of commercial (Fluka) naphthenic acids on acid volatile sulfide (AVS) production and divalent metal precipitation.

Science.gov (United States)

McQueen, Andrew D; Kinley, Ciera M; Rodgers, John H; Friesen, Vanessa; Bergsveinson, Jordyn; Haakensen, Monique C

2016-12-01

Energy-derived waters containing naphthenic acids (NAs) are complex mixtures often comprising a suite of potentially problematic constituents (e.g. organics, metals, and metalloids) that need treatment prior to beneficial use, including release to receiving aquatic systems. It has previously been suggested that NAs can have biostatic or biocidal properties that could inhibit microbially driven processes (e.g. dissimilatory sulfate reduction) used to transfer or transform metals in passive treatment systems (i.e. constructed wetlands). The overall objective of this study was to measure the effects of a commercially available (Fluka) NA on sulfate-reducing bacteria (SRB), production of sulfides (as acid-volatile sulfides [AVS]), and precipitation of divalent metals (i.e. Cu, Ni, Zn). These endpoints were assessed following 21-d aqueous exposures of NAs using bench-scale reactors. After 21-days, AVS molar concentrations were not statistically different (pAVS production was sufficient in all NA treatments to achieve ∑SEM:AVS AVS) could be used to treat metals occurring in NAs affected waters. Copyright © 2016 Elsevier Inc. All rights reserved.

[Studies on interaction of acid-treated nanotube titanic acid and amino acids].

Science.gov (United States)

Zhang, Huqin; Chen, Xuemei; Jin, Zhensheng; Liao, Guangxi; Wu, Xiaoming; Du, Jianqiang; Cao, Xiang

2010-06-01

Nanotube titanic acid (NTA) has distinct optical and electrical character, and has photocatalysis character. In accordance with these qualities, NTA was treated with acid so as to enhance its surface activity. Surface structures and surface groups of acid-treated NTA were characterized and analyzed by Transmission Electron Microscope (TEM) and Fourier Transform Infrared Spectrometry (FT-IR). The interaction between acid-treated NTA and amino acids was investigated. Analysis results showed that the lengths of acid-treated NTA became obviously shorter. The diameters of nanotube bundles did not change obviously with acid-treating. Meanwhile, the surface of acid-treated NTA was cross-linked with carboxyl or esterfunction. In addition, acid-treated NTA can catch amino acid residues easily, and then form close combination.

Modelling the factors influencing the selection of the construction equipment for Indian construction organizations

Directory of Open Access Journals (Sweden)

S.V.S. Raja Prasad

2016-09-01

Full Text Available The contribution of Indian construction sector to the GDP is approximately 10%. Under new government policy, it is anticipated that $1000 Billion share for exclusively infrastructure segment would be completed within the next few years. Construction sector in developing country like India still depends on labor and the practice of mechanization, adopting to use of versatile construction equipment is not in force. The need for implementing new technologies and automation is essential to improve the quality, safety and efficiency. To meet the challenges ahead the construction, organizations should focus on utilization of machinery/equipment to achieve desirable results. Modern construction is characterized by the increase in utilization of equipment to accomplish numerous construction activities. The selection of construction equipment often affects the required amount of time and effort. It is therefore important for managements of construction organizations and planners to be familiar with the features of various types of equipment commonly used in construction activities. The selection of appropriate equipment is a crucial decision making process as it involves huge capital investment. The purpose of the present study is to develop a model pertaining to the factors influencing the selection of construction equipment by using interpretive structural modelling and the results indicate that productivity and safety are the important factors in selection of equipment in Indian construction organizations.

Ti(Oi-Pr)4-promoted photoenolization Diels-Alder reaction to construct polycyclic rings and its synthetic applications.

Science.gov (United States)

Yang, Baochao; Lin, Kuaikuai; Shi, Yingbo; Gao, Shuanhu

2017-09-20

Stereoselective construction of polycyclic rings with all-carbon quaternary centers, and vicinal all-carbon quaternary stereocenters, remains a significant challenge in organic synthesis. These structures can be found in a wide range of polycyclic natural products and drug molecules. Here we report a Ti(Oi-Pr) 4 -promoted photoenolization/Diels-Alder (PEDA) reaction to construct hydroanthracenol and related polycyclic rings bearing all-carbon quaternary centers. This photolysis proceeds under mild conditions and generates a variety of photo-cycloaddition products in good reaction efficiency and stereoselectivity (48 examples), and has been successfully used in the construction of core skeleton of oncocalyxones, tetracycline and pleurotin. It also provides a reliable method for the late-stage modification of natural products bearing enone groups, such as steroids. The total synthesis of oncocalyxone B was successfully achieved using this PEDA approach.Anthracenols with multiple chiral centres are common motifs in natural products. Here, the authors show a highly stereoselective photoenolization/Diels-Alder methodology involving a key Lewis acid reagent enabling the efficient construction of a family of anthracenol derivatives with quaternary centers.

Economic assessment of the construction industry: A construction-economics nexus

Science.gov (United States)

Barber, Herbert Marion, Jr.

The purpose of this study was to conduct an economic assessment of the construction industry. More specifically, this study addresses ambiguities within the literature that are associated with the construction-economics nexus. The researcher 1) investigated the relationships between economic indicators and stock prices of U.S. construction equipment manufacturers, 2) investigated the relationships between energy production, consumption, and corruption, and 3) determined the economic effect electricity generation and electricity consumption has on economies of scale. The researcher used descriptive and inferential statistics in this study and determined that economists, researchers, policy-makers, and others should have predicted the 2007-08 world economic collapse 5-6 years prior to realization of the event given that construction indices and GDP grossly regressed from statistically acceptable trends as early as 2002 and perhaps 2000. Substantiating this claim, the effect of the cost of construction materials and labor, i.e. construction index, on GDP was significant for years leading up to the collapse (1970-2007). Additionally, it was determined that energy production and consumption are predictors of governmental corruption in some countries. In the Republic of Botswana, for example, the researcher determined that energy production and consumption statistically jointly effected governmental corruption. In addition to determining statistical effect, a model for predicting governmental corruption was developed based on energy production and consumption volumes. Also, the researcher found that electricity generation in the 25 largest world economies had a statistically significant effect on GDP. Electricity consumption also had an effect on GDP, as well, but not on other economic indicators. More importantly than the quantitative findings, the researcher concluded that the construction-economics nexus is far more complex than most policy-makers realize. As such

USAID Construction Assessment

Data.gov (United States)

US Agency for International Development — The USAID construction assessment is a survey of the character, scope, value and management of construction activities supported by USAID during the period from June...

Changes in Oleic Acid Content of Transgenic Soybeans by Antisense RNA Mediated Posttranscriptional Gene Silencing

Directory of Open Access Journals (Sweden)

Ling Zhang

2014-01-01

Full Text Available The Delta-12 oleate desaturase gene (FAD2-1, which converts oleic acid into linoleic acid, is the key enzyme determining the fatty acid composition of seed oil. In this study, we inhibited the expression of endogenous Delta-12 oleate desaturase GmFad2-1b gene by using antisense RNA in soybean Williams 82. By employing the soybean cotyledonary-node method, a part of the cDNA of soybean GmFad2-1b 801 bp was cloned for the construction of a pCAMBIA3300 vector under the soybean seed promoter BCSP. Leaf painting, LibertyLink strip, PCR, Southern blot, qRT-PCR, and fatty acid analysis were used to detect the insertion and expression of GmFad2-1b in the transgenic soybean lines. The results indicate that the metabolically engineered plants exhibited a significant increase in oleic acid (up to 51.71% and a reduction in palmitic acid (to <3% in their seed oil content. No structural differences were observed between the fatty acids of the transgenic and the nontransgenic oil extracts.

Porous carbon-coated ZnO nanoparticles derived from low carbon content formic acid-based Zn(II) metal-organic frameworks towards long cycle lithium-ion anode material

International Nuclear Information System (INIS)

Gao, Song; Fan, Ruiqing; Li, Bingjiang; Qiang, Liangsheng; Yang, Yulin

2016-01-01

Graphical abstract: The nanocomposites constructed from Zn-based MOFs exhibit low carbon content with super-high rate capability and long cycling life. - Highlights: • Novel ZnO@porous carbon matrix nanocomposites are constructed by pyrolysis of Zn-based MOFs. • The nanocomposites constructed with Zn-based MOFs show low carbon content. • The constructed nanocomposites exhibit high energy density, super-high rate capability and long cycling life. - Abstract: Single-C formic acid-based metal-organic frameworks (MOFs) are used to construct novel ZnO@porous carbon matrix nanocomposites by controlled pyrolysis. In the constructed nanocomposites, the porous carbon matrices act as a confined support to prevent agglomeration of the ZnO nanoparticles and create a rapid electron conductive network. Meanwhile, the well-defined, continuous porous structured MOFs provide a large specific surface area, which increases the contact of electrolyte-electrode and improves the penetration of electrolyte. Especially, the reasonable choice of formic acid-based MOFs construct the low carbon content composite, which contribute to the high energy density and long cycle life. The constructed nanocomposites show stable, ultrahigh rate lithium ion storage properties of 650 mAh g −1 at charge/discharge rate of 1 C even after 200 cycles.

Construction mediation and its hybridization: the case of the Hong Kong construction industry

Directory of Open Access Journals (Sweden)

Ng Pui-Lam

2017-01-01

Full Text Available In view of the sophisticated nature of construction disputes, specialized dispute resolution mechanisms are of pivotal importance to the satisfactory settlement between disputing parties. Among the various construction dispute resolution mechanisms, mediation has been increasingly gaining recognition and acceptance. Its hybrid, namely mediation-arbitration (med-arb, has also emerged and has started receiving attention and appreciation. With special reference to the construction industry practice in Hong Kong, a commentary on the respective merits and demerits of construction mediation and construction med-arb, as well as the ways forward, are presented in this article.

Nucleic acid nanostructures: bottom-up control of geometry on the nanoscale

International Nuclear Information System (INIS)

Seeman, Nadrian C; Lukeman, Philip S

2005-01-01

DNA may seem an unlikely molecule from which to build nanostructures, but this is not correct. The specificity of interaction that enables DNA to function so successfully as genetic material also enables its use as a smart molecule for construction on the nanoscale. The key to using DNA for this purpose is the design of stable branched molecules, which expand its ability to interact specifically with other nucleic acid molecules. The same interactions used by genetic engineers can be used to make cohesive interactions with other DNA molecules that lead to a variety of new species. Branched DNA molecules are easy to design, and they can assume a variety of structural motifs. These can be used for purposes both of specific construction, such as polyhedra, and for the assembly of topological targets. A variety of two-dimensional periodic arrays with specific patterns have been made. DNA nanomechanical devices have been built with a series of different triggers, small molecules, nucleic acid molecules and proteins. Recently, progress has been made in self-replication of DNA nanoconstructs, and in the scaffolding of other species into DNA arrangements

Acid digestion and pressurization control in combustible radwaste treatment

International Nuclear Information System (INIS)

Allen, C.R.; Cowan, R.G.; Grelecki, C.J.

1978-01-01

Acid digestion has been developed to reduce the volume of combustible nuclear waste materials, while converting them to an inert, noncombustible residue. A 100 kg/day test unit has recently been constructed to process radioactively contaminated combustible wastes. The unit, called the Radioactive Acid Digestion Test Unit (RADTU) was completed in September, 1977, and is currently undergoing nonradioactive shakedown tests. Radioactive operation is expected in May, 1978. Because of uncertainties in waste composition and reactivity, the system was required to contain pressurizations. This led to the development of a simple and inexpensive system, which is capable of attenuating a shock wave from a full scale vapor detonation. The system has potential application in a wide spectrum of chemical reactors, since the fabrication materials are resistant to a very wide range of corrosive chemical attack

Ibotenic acid and thioibotenic acid

DEFF Research Database (Denmark)

Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte

2004-01-01

In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid...... with the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for thioibotenic acid...

The Influence of Organizational External Factors on Construction Risk Management among Nigerian Construction Companies

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A.Q. Adeleke

2018-03-01

Full Text Available Background: Substantial empirical research has shown conflicting results regarding the influence of organizational external factors on construction risk management, suggesting the necessity to introduce a moderator into the study. The present research confirmed whether rules and regulations matter on the relationships between organizational external factors and construction risk management. Methods: Based on discouragement and organizational control theory, this research examined the effects of organizational external factors and rules and regulations on construction risk management among 238 employees operating in construction companies in Abuja and Lagos, Nigeria. A personally administered questionnaire was used to acquire the data. The data were analyzed using partial least squares structural equation modeling. Results: A significant positive relationship between organizational external factors and construction risk management was asserted. This study also found a significant positive relationship between rules and regulations and construction risk management. As anticipated, rules and regulations were found to moderate the relationship between organizational external factors and construction risk management, with a significant positive result. Similarly, a significant interaction effect was also found between rules and regulations and organizational external factors. Implications of the research from a Nigerian point of view have also been discussed. Conclusion: Political, economy, and technology factors helped the construction companies to reduce the chance of risk occurrence during the construction activities. Rules and regulations also helped to lessen the rate of accidents involving construction workers as well as the duration of the projects. Similarly, the influence of the organizational external factors with rules and regulations on construction risk management has proven that most of the construction companies that implement the

NMR studies of inclusion complexes formed by (R)-α-lipoic acid with α-, β-, and γ-cyclodextrins

International Nuclear Information System (INIS)

Ikeda, Hiroshi; Ikuta, Naoko; Nakata, Daisuke; Ishida, Yoshiyuki; Terao, Keiji

2015-01-01

The structures of inclusion complexes of (R)-α-lipoic acid with α-, β-, and γ-cyclodextrin (CD) were constructed using restraints derived from ROESY spectra and MMFF94 molecular mechanics calculations. (R)-α-lipoic acid and α-CD generate a single stable inclusion complex, in which the 1,2-dithiolane ring of the (R)-α-lipoic acid is oriented toward the secondary hydroxy side of the α-CD. NMR data suggests that β-CD produces two kinds of inclusion complexes with α-lipoic acid. Finally, γ-CD yields 1:1 and 1:2 host/guest complexes with (R)-α-lipoic acid. The estimated structure of the 1:1 γ-CD inclusion complex has the 1,2-dithiolane ring oriented toward the primary hydroxy side of the γ-CD. (author)

An alignment-free method to find similarity among protein sequences via the general form of Chou's pseudo amino acid composition.

Science.gov (United States)

Gupta, M K; Niyogi, R; Misra, M

2013-01-01

In this paper, we propose a method to create the 60-dimensional feature vector for protein sequences via the general form of pseudo amino acid composition. The construction of the feature vector is based on the contents of amino acids, total distance of each amino acid from the first amino acid in the protein sequence and the distribution of 20 amino acids. The obtained cosine distance metric (also called the similarity matrix) is used to construct the phylogenetic tree by the neighbour joining method. In order to show the applicability of our approach, we tested it on three proteins: 1) ND5 protein sequences from nine species, 2) ND6 protein sequences from eight species, and 3) 50 coronavirus spike proteins. The results are in agreement with known history and the output from the multiple sequence alignment program ClustalW, which is widely used. We have also compared our phylogenetic results with six other recently proposed alignment-free methods. These comparisons show that our proposed method gives a more consistent biological relationship than the others. In addition, the time complexity is linear and space required is less as compared with other alignment-free methods that use graphical representation. It should be noted that the multiple sequence alignment method has exponential time complexity.

Advanced construction methods in ACR

International Nuclear Information System (INIS)

Elgohary, M.; Choy, E.; Yu, S.K.W.

2002-01-01

The ACR - Advanced CANDU Reactor, developed by Atomic Energy of Canada Limited (AECL), is designed with constructability considerations as a major requirement during all project phases from the concept design stage to the detail design stage. This necessitated a much more comprehensive approach in including constructability considerations in the design to ensure that the construction duration is met. For the ACR-700, a project schedule of 48 months has been developed for the nth replicated unit with a 36 month construction period duration from First Concrete to Fuel Load. An overall construction strategy that builds on the success of the construction methods that are proven in the construction of the Qinshan CANDU 6 project has been developed for the ACR. The overall construction strategy comprises the 'Open Top' construction technique using a Very Heavy Lift crane, parallel construction activities, with extensive modularization and prefabrication. In addition, significant applications of up to date construction technology will be implemented, e.g. large volume concrete pours, prefabricated rebar, use of climbing forms, composite structures, prefabricated permanent formwork, automatic welding, and utilization of the latest electronic technology tools such as 3D CADDs modelling yields a very high quality, clash free product to allow construction to be completed 'right the first time' and eliminates rework. Integration of 3D CADDs models and scheduling tools such as Primavera has allowed development of actual construction sequences and an iterative approach to schedule verification and improvement. Modularization and prefabrication are major features of the ACR design in order to achieve the project schedule. For the reactor building approximately 80% of the volume will be installed as modules or prefabricated assembles. This ensures critical path activities are achieved. This paper examines the advanced construction methods implemented in the design in order to

Model Tests on the Retaining Walls Constructed from Geobags Filled with Construction Waste

OpenAIRE

Wen, Hua; Wu, Jiu-jiang; Zou, Jiao-li; Luo, Xin; Zhang, Min; Gu, Chengzhuang

2016-01-01

Geobag retaining wall using construction waste is a new flexible supporting structure, and the usage of construction waste to fill geobags can facilitate the construction recycling. In this paper, model tests were performed on geobag retaining wall using construction waste. The investigation was concentrated on the slope top settlement, the distribution characteristics of the earth pressures on retaining walls and horizontal wall displacements, and slope failure modes. The results indicated t...

BER-Myriant Succinic Acid Biorefinery

Energy Technology Data Exchange (ETDEWEB)

Shmorhun, Mark [Myriant Lake Providence, Inc., Lake Providence, LA (United States)

2015-12-31

Myriant Corporation (Myriant) has successfully produced the bioproduct succinic acid by the fermentation of glucose at a commercial scale operation in Lake Providence, Louisiana. The MySAB facility (Myriant Succinic Acid Biorefinery) came on stream in May 2013 and has been producing product since then. The MySAB facility is a demonstration-scale plant, capable of utilizing sorghum grits and commercially available dextrose, to ferment glucose into succinic acid. A downstream processing train has demonstrated the ability to produce an industrial, a standard and a polymer grade product. It consists of cell separation, membrane filtration, continuous chromatography, polishing to remove ionic and color bodies impurities, and final evaporation and crystallization. A by-product of the process is ammonium sulfate which is sold as a liquid fertilizer product. Since 2007 when development work began in the Woburn, Massachusetts R&D laboratories, the succinic acid bio-process has evolved through: Process development (microbiology, fermentation, and downstream) – R&D development laboratories; Piloting efforts at Fermic S.A. de C.V., Mexico City, Mexico – upstream and downstream processes; Design, construction, commissioning, and commercial production operations at the MySAB facility Additionally, Myriant became a wholly-owned subsidiary of the PTT Global Chemical Plc., Thailand, in late 2015, their investment into and support of Myriant goes back to 2011. The support of PTT Global Chemical Plc. helped to improve the upstream and downstream processes, and produce significant metric ton quantities of high quality bio-based succinic acid. The product has gone into a number of commercial markets worldwide for customer applications, development and production. The experience base gained via operations at the MySAB facility since May 2013, along with continued R&D development efforts involving Microbiology, Fermentation, and Downstream processes, at both the Woburn, Massachusetts

23 CFR 660.113 - Construction.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Construction. 660.113 Section 660.113 Highways FEDERAL... (DIRECT FEDERAL) Forest Highways § 660.113 Construction. (a) No construction shall be undertaken on any FH... construction of FHs will be performed by the contract method, unless construction by the FHWA, the FS, or a...

Metabolic Engineering of Probiotic Saccharomyces boulardii.

Science.gov (United States)

Liu, Jing-Jing; Kong, In Iok; Zhang, Guo-Chang; Jayakody, Lahiru N; Kim, Heejin; Xia, Peng-Fei; Kwak, Suryang; Sung, Bong Hyun; Sohn, Jung-Hoon; Walukiewicz, Hanna E; Rao, Christopher V; Jin, Yong-Su

2016-04-01

Saccharomyces boulardiiis a probiotic yeast that has been used for promoting gut health as well as preventing diarrheal diseases. This yeast not only exhibits beneficial phenotypes for gut health but also can stay longer in the gut than Saccharomyces cerevisiae Therefore, S. boulardiiis an attractive host for metabolic engineering to produce biomolecules of interest in the gut. However, the lack of auxotrophic strains with defined genetic backgrounds has hampered the use of this strain for metabolic engineering. Here, we report the development of well-defined auxotrophic mutants (leu2,ura3,his3, and trp1) through clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9-based genome editing. The resulting auxotrophic mutants can be used as a host for introducing various genetic perturbations, such as overexpression or deletion of a target gene, using existing genetic tools forS. cerevisiae We demonstrated the overexpression of a heterologous gene (lacZ), the correct localization of a target protein (red fluorescent protein) into mitochondria by using a protein localization signal, and the introduction of a heterologous metabolic pathway (xylose-assimilating pathway) in the genome ofS. boulardii We further demonstrated that human lysozyme, which is beneficial for human gut health, could be secreted by S. boulardii Our results suggest that more sophisticated genetic perturbations to improveS. boulardii can be performed without using a drug resistance marker, which is a prerequisite for in vivo applications using engineeredS. boulardii. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Constructability and maintainability

International Nuclear Information System (INIS)

Hart, R.S.

1985-01-01

A set of principles for minimizing the construction schedule was established at the outset of the CANDU 300 programme. Consideration of these principles and other factors led to the development of the unique CANDU 300 station layout. The paper discusses the CANDU 300 station layout and construction methods. In summary, the station layout provides 360 deg. construction access to all buildings, separation of nuclear and non-nuclear systems, precise and minimal physical interfaces between buildings, accommodation of many contractors and construction activities without interference, and maximum flexibility in terms of constructional, financial and supply arrangements. The CANDU 300 further employs modularization, shop fabrication and advanced instrumentation (multiplexers, remote processors, data highways) to minimize construction time. Many of the CANDU 300 features that enhance constructability also contribute to maintainability. These include the 360 deg. access to all principal buildings, the uncluttered and spacious building layouts, the simplification of systems and the high level of modularization. The CANDU 300 has also been designed to facilitate the replacement of all key components, thereby offering an essentially unlimited station life. A prime example is a reduction in the fuel channel inlet end-fitting diameter such that the fuel channels can be shop assembled and easily replaced after the initial 40 years of operation, without an extended unit outage. Maintainability within the reactor building has been given particular attention in the CANDU 300 design; key features of other CANDU reactors (the ability to replace a heat transport system pump motor at power, for example) have been incorporated, while accessibility and maintainability of all systems and components have been enhanced. These and other aspects of maintainability are discussed. (author)

Engineering nucleic acid structures for programmable molecular circuitry and intracellular biocomputation

Science.gov (United States)

Li, Jiang; Green, Alexander A.; Yan, Hao; Fan, Chunhai

2017-11-01

Nucleic acids have attracted widespread attention due to the simplicity with which they can be designed to form discrete structures and programmed to perform specific functions at the nanoscale. The advantages of DNA/RNA nanotechnology offer numerous opportunities for in-cell and in-vivo applications, and the technology holds great promise to advance the growing field of synthetic biology. Many elegant examples have revealed the potential in integrating nucleic acid nanostructures in cells and in vivo where they can perform important physiological functions. In this Review, we summarize the current abilities of DNA/RNA nanotechnology to realize applications in live cells and then discuss the key problems that must be solved to fully exploit the useful properties of nanostructures. Finally, we provide viewpoints on how to integrate the tools provided by DNA/RNA nanotechnology and related new technologies to construct nucleic acid nanostructure-based molecular circuitry for synthetic biology.

State of the art on construction automation and robotic system in domestic and foreign construction industry

International Nuclear Information System (INIS)

Lee, Sung Uk; Seo, Yong Chil; Jung, Seung Ho; Cho, Jai Wan; Choi, Young Soo

2007-08-01

In this report, we review the existing concept of construction automation and also survey the state of the art on construction automation and robotic system in domestic and foreign construction industry. On the basis of the result of review and survey, we want to suggest an applicable robotic technology to construction industry and points to be duly considered for activating construction automation. We investigate the state of the art on construction automation and robotic system in domestic and foreign construction industry and also applicable area and direction of domestic construction automation and robotic system. We hope that construction automation and robotic technology, which are improved rapidly nowadays, can contribute to the growth of construction industry

Construction safety

CERN Document Server

Li, Rita Yi Man

2013-01-01

A close-to-ideal blend of suburb and city, speedy construction of towers of Babylon, the sparkling proportion of glass and steel buildings’ facade at night showcase the wisdom of humans. They also witness the footsteps, sweats and tears of architects and engineers. Unfortunately, these signatures of human civilizations are swathed in towering figures of construction accidents. Fretting about these on sites, different countries adopt different measures on sites. This book firstly sketches the construction accidents on sites, followed by a review on safety measures in some of the developing countries such as Bermuda, Egypt, Kuwait and China; as well as developed countries, for example, the United States, France and Singapore. It also highlights the enormous compensation costs with the courts’ experiences in the United Kingdom and Hong Kong.

STIMULATION OF CONSTRUCTION OF AFFORDABLE HOUSING BY REFORMATION OF A CONSTRUCTION COMPLEX MANAGEMENT SYSTEM

Directory of Open Access Journals (Sweden)

BRONEVYTSKYI S. P.

2015-10-01

Full Text Available Purpose. Development of offers on stimulation of construction of affordable housing by reformation of a construction complex management system. Methodology. The revelation of the problems of planning of construction in large cities. The analysis of forming of structure of a build complex management in soviet times and in a transitional period. The revelation of the modern, actual, socio-economic problems of the construction activity management. Proposition on the improvement of methods of construction management in cities of Ukraine. Results. The methods of a construction complex management in countries with a market economy as for building of affordable housing are shown. Originality. In composition of a town-planning documentations, except for the norms of the common use of territories of city (density of population of micro region, the maximum parameters of a construction examining of land areas are proposed to determine: building percent and coefficient of maximum superficial area. Practical value. The principle of management and organization of construction is norms of a build use of territories for building of mass affordable housing for funds of population and investors while providing of the comfort of housing in accordance with state construction norms.

Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

Directory of Open Access Journals (Sweden)

Koji Sode

2012-11-01

Full Text Available Mutagenesis studies on glucose oxidases (GOxs were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe and Aspergillus niger GOx (PDB ID; 1cf3. We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

Lipid and fatty acid metabolism in Ralstonia eutropha: relevance for the biotechnological production of value-added products.

Science.gov (United States)

Riedel, Sebastian L; Lu, Jingnan; Stahl, Ulf; Brigham, Christopher J

2014-02-01

Lipid and fatty acid metabolism has been well studied in model microbial organisms like Escherichia coli and Bacillus subtilis. The major precursor of fatty acid biosynthesis is also the major product of fatty acid degradation (β-oxidation), acetyl-CoA, which is a key metabolite for all organisms. Controlling carbon flux to fatty acid biosynthesis and from β-oxidation allows for the biosynthesis of natural products of biotechnological importance. Ralstonia eutropha can utilize acetyl-CoA from fatty acid metabolism to produce intracellular polyhydroxyalkanoate (PHA). R. eutropha can also be engineered to utilize fatty acid metabolism intermediates to produce different PHA precursors. Metabolism of lipids and fatty acids can be rerouted to convert carbon into other value-added compounds like biofuels. This review discusses the lipid and fatty acid metabolic pathways in R. eutropha and how they can be used to construct reagents for the biosynthesis of products of industrial importance. Specifically, how the use of lipids or fatty acids as the sole carbon source in R. eutropha cultures adds value to these biotechnological products will be discussed here.

NOx generation method from recovered nitric acid by electrolysis

International Nuclear Information System (INIS)

Suzuki, Y.; Shimizu, H.; Inoue, M.; Fujiso, M.; Shibuya, M.; Iwamoto, F.; Outou, Y.; Ochi, E.; Tsuyuki, T.

1998-01-01

An R and D has been conducted on an electrolytic NO x generation process utilizing recovered nitric acid from a PUREX reprocessing plant. The purpose of the study is to drastically reduce the amount of low-level-liquid waste(LLW). The research program phase-1, constituting mainly of electrochemical reaction mechanism study, material balance evaluation and process design study, finished in 1995. The results were presented in the previous papers). The research program phase-2 has started in 1995. The schedule is as follows: FY 1991-1994: Research program phase-1 Basic study using electrolysis equipment with 100-700 cm 2 electrodes FY 1995-1999: Research program phase-2 Process performance test by larger scale electrolysis equipment with 3.6 m 2 electrodes - pilot plant design (FY 1995) - pilot plant construction (FY 1996) - engineering data acquisition (FY 1997-1999). The process consists of many unit operations such as electrolysis, oxidation, nitric acid concentration, NO x compression and storage, NO x recovery, off-gas treatment and acid supplier. This paper outlines the pilot test plant. (author)

Dynamic culture of a thermosensitive collagen hydrogel as an extracellular matrix improves the construction of tissue-engineered peripheral nerve.

Science.gov (United States)

Huang, Lanfeng; Li, Rui; Liu, Wanguo; Dai, Jin; Du, Zhenwu; Wang, Xiaonan; Ma, Jianchao; Zhao, Jinsong

2014-07-15

Tissue engineering technologies offer new treatment strategies for the repair of peripheral nerve injury, but cell loss between seeding and adhesion to the scaffold remains inevitable. A thermosensitive collagen hydrogel was used as an extracellular matrix in this study and combined with bone marrow mesenchymal stem cells to construct tissue-engineered peripheral nerve composites in vitro. Dynamic culture was performed at an oscillating frequency of 0.5 Hz and 35° swing angle above and below the horizontal plane. The results demonstrated that bone marrow mesenchymal stem cells formed membrane-like structures around the poly-L-lactic acid scaffolds and exhibited regular alignment on the composite surface. Collagen was used to fill in the pores, and seeded cells adhered onto the poly-L-lactic acid fibers. The DNA content of the bone marrow mesenchymal stem cells was higher in the composites constructed with a thermosensitive collagen hydrogel compared with that in collagen I scaffold controls. The cellular DNA content was also higher in the thermosensitive collagen hydrogel composites constructed with the thermosensitive collagen hydrogel in dynamic culture than that in static culture. These results indicate that tissue-engineered composites formed with thermosensitive collagen hydrogel in dynamic culture can maintain larger numbers of seeded cells by avoiding cell loss during the initial adhesion stage. Moreover, seeded cells were distributed throughout the material.

Mechanism of catalytic action of oxide systems in reactions of aldehyde oxidation to carboxylic acids

International Nuclear Information System (INIS)

Andrushkevich, T.V.

1997-01-01

Mechanism of selective action of oxide catalysts (on the base of V 2 O 4 , MoO 3 ) of aldehyde oxidation to acids is considered, reaction acrolein oxidation to acrylic acid is taken as an example. Multistage mechanism of the process is established; it involves consequent transformation of coordination-bonded aldehyde into carbonyl-bonded aldehyde and symmetric carboxylate. Principles of active surface construction are formulated, they take into account the activity of stabilization center of concrete intermediate compound and bond energy of oxygen with surface. (author)

Growing Escherichia coli mutants deficient in riboflavin biosynthesis with non-limiting riboflavin results in sensitization to inactivation by broad-spectrum near-ultraviolet light (320-400 nm)

International Nuclear Information System (INIS)

Lloyd, R.E.; Rinkenberger, J.L.; Hug, B.A.; Tuveson, R.W.

1990-01-01

Two mutants of Escherichia coli unable to synthesize riboflavin were grown with limiting (2 μg ml -1 ) and non-limiting (10 μg ml -1 ) concentrations of riboflavin. These riboflavin auxotrophs when grown to exponential phase with non-limiting riboflavin are more sensitive to broad spectrum near-ultraviolet light (NUV, 320-400 nm) inactivation than when they are grown with limiting riboflavin. Exponential phase cells of the riboflavin auxotrophs grown with limiting riboflavin are sensitized when irradiated in saline supplemented with riboflavin. This suggests that extracellular riboflavin is important as a NUV sensitizer when intracellular levels of riboflavin are reduced. The concentration of riboflavin in crude extracts from exponentially growing cells correlates well with the sensitivity of these mutants to NUV inactivation. The level of riboflavin supplementation has little effect on the NUV sensitivity of the parental strain. (author)

[Acids in coffee. XI. The proportion of individual acids in the total titratable acid].

Science.gov (United States)

Engelhardt, U H; Maier, H G

1985-07-01

22 acids in ground roast coffees and instant coffees were determined by GLC of their silyl derivatives (after preseparation by gel electrophoresis) or isotachophoresis. The contribution to the total acidity (which was estimated by titration to pH 8 after cation exchange of the coffee solutions) was calculated for each individual acid. The mentioned acids contribute with 67% (roast coffee) and 72% (instant coffee) to the total acidity. In the first place citric acid (12.2% in roast coffee/10.7% in instant coffee), acetic acid (11.2%/8.8%) and the high molecular weight acids (8%/9%) contribute to the total acidity. Also to be mentioned are the shares of chlorogenic acids (9%/4.8%), formic acid (5.3%/4.6%), quinic acid (4.7%/5.9%), malic acid (3.9%/3%) and phosphoric acid (2.5%/5.2%). A notable difference in the contribution to total acidity between roast and instant coffee was found for phosphoric acid and pyrrolidonecarboxylic acid (0.7%/1.9%). It can be concluded that those two acids are formed or released from e.g. their esters in higher amounts than other acids during the production of instant coffee.

Metabolic Engineering of the Shikimate Pathway for Production of Aromatics and Derived Compounds—Present and Future Strain Construction Strategies

Directory of Open Access Journals (Sweden)

Nils J. H. Averesch

2018-03-01

Full Text Available The aromatic nature of shikimate pathway intermediates gives rise to a wealth of potential bio-replacements for commonly fossil fuel-derived aromatics, as well as naturally produced secondary metabolites. Through metabolic engineering, the abundance of certain intermediates may be increased, while draining flux from other branches off the pathway. Often targets for genetic engineering lie beyond the shikimate pathway, altering flux deep in central metabolism. This has been extensively used to develop microbial production systems for a variety of compounds valuable in chemical industry, including aromatic and non-aromatic acids like muconic acid, para-hydroxybenzoic acid, and para-coumaric acid, as well as aminobenzoic acids and aromatic α-amino acids. Further, many natural products and secondary metabolites that are valuable in food- and pharma-industry are formed outgoing from shikimate pathway intermediates. (Reconstruction of such routes has been shown by de novo production of resveratrol, reticuline, opioids, and vanillin. In this review, strain construction strategies are compared across organisms and put into perspective with requirements by industry for commercial viability. Focus is put on enhancing flux to and through shikimate pathway, and engineering strategies are assessed in order to provide a guideline for future optimizations.

Evaluating the efficacy of a structure-derived amino acid substitution matrix in detecting protein homologs by BLAST and PSI-BLAST

Directory of Open Access Journals (Sweden)

Nalin CW Goonesekere

2009-06-01

Full Text Available Nalin CW GoonesekereDepartment of Chemistry and Biochemistry, University of Northern iowa, Cedar Falls, IA, USAAbstract: The large numbers of protein sequences generated by whole genome sequencing projects require rapid and accurate methods of annotation. The detection of homology through computational sequence analysis is a powerful tool in determining the complex evolutionary and functional relationships that exist between proteins. Homology search algorithms employ amino acid substitution matrices to detect similarity between proteins sequences. The substitution matrices in common use today are constructed using sequences aligned without reference to protein structure. Here we present amino acid substitution matrices constructed from the alignment of a large number of protein domain structures from the structural classification of proteins (SCOP database. We show that when incorporated into the homology search algorithms BLAST and PSI-blaST, the structure-based substitution matrices enhance the efficacy of detecting remote homologs. Keywords: computational biology, protein homology, amino acid substitution matrix, protein structure

Worldwide construction

International Nuclear Information System (INIS)

Williamson, M.

1994-01-01

The paper lists major construction projects in worldwide processing and pipelining, showing capacities, contractors, estimated costs, and time of construction. The lists are divided into refineries, petrochemical plants, sulfur recovery units, gas processing plants, pipelines, and related fuel facilities. This last classification includes cogeneration plants, coal liquefaction and gasification plants, biomass power plants, geothermal power plants, integrated coal gasification combined-cycle power plants, and a coal briquetting plant

The neutralization of acidic coal mine lakes by additions of natural organic matter: a mesocosm test

International Nuclear Information System (INIS)

Brugam, R.B.; Gastineau, J.; Ratcliff, E.

1995-01-01

Cylindrical polyethylene enclosures 3 m in length and 1 m in diameter reaching from the surface to the bottom were constructed in an acid (pH=3.1) lake on a coal surface mine in southern Illinois. Wheat straw was added to the enclosures to test the effects of dissimilatory sulfate reduction on water chemistry. Added straw increased sulfide concentrations, raised pH to 6.5, reduced O 2 and increased acid neutralizing capacity of the enclosed water columns when compared with a control enclosure and with the open lake. Generation of acid neutralizing capacity exceeded the standing stock of sulfide indicating that sulfide was removed either by precipitation of FeS or outgassing of H 2 S. The pH and acid neutralizing capacity within the enclosures eventually returned to the level of the surrounding lake because of water exchange around the enclosure walls. Our results show that additions of organic matter to acid surface mine lakes result in the generation of acid neutralizing capacity

Operation of the radioactive acid digestion test unit

International Nuclear Information System (INIS)

Blasewitz, A.G.; Allen, C.R.; Lerch, R.E.; Ely, P.C.; Richardson, G.L.

1980-01-01

The Radioactive Acid Digestion Test Unit (RADTU) has been constructed at Hanford to demonstrate the application of the Acid Digestion Process for treating combustible transuranic wastes and scrap materials. The RADTU with its original tray digestion vessel has recently completed a six-month campaign processing potentially contaminated nonglovebox wastes from a Hanford plutonium facility. During this campaign, it processed 2100 kg of largely cellulosic wastes at an average sustained processing rate of 3 kg/h as limited by the water boiloff rate from the acid feeds. The on-line operating efficiency was nearly 50% on a twelve hour/day, five day/week basis. Following this campaign, a new annular high rate digester has been installed for testing. In preliminary tests with simulated wastes, the new digester demonstrated a sustained capacity of 10 kg/h with greatly improved intimacy of contact between the digestion acid and the waste. The new design also doubles the heat transfer surface, which with reduced heat loss area, is expected to provide at least three times the water boiloff rate of the previous tray digester design. Following shakedown testing with simulated and low-level wastes, the new unit will be used to process combustible plutonium scrap and waste from Hanford plutonium facilities for the purposes of volume reduction, plutonium recovery, and stabilization of the final waste form

Development and testing of a bipolar lead-acid battery for hybrid electric vehicles

NARCIS (Netherlands)

Saakes, M.; Kluiters, E.; Schmal, D.; Mourad, S.; Have, P.T.J.H. ten

1999-01-01

An 80 V bipolar lead-acid battery was constructed and tested using hybrid electric vehicle (HEV) drive cycles. Drive cycles with a peak power of 6.7 kW, equal to 1/5 of the total power profile required for the HEV studied, were run successfully. Model calculations showed that the 80 V module

Overexpression of the NADP+-specific isocitrate dehydrogenase gene (icdA) in citric acid-producing Aspergillus niger WU-2223L.

Science.gov (United States)

Kobayashi, Keiichi; Hattori, Takasumi; Hayashi, Rie; Kirimura, Kohtaro

2014-01-01

In the tricarboxylic acid (TCA) cycle, NADP(+)-specific isocitrate dehydrogenase (NADP(+)-ICDH) catalyzes oxidative decarboxylation of isocitric acid to form α-ketoglutaric acid with NADP(+) as a cofactor. We constructed an NADP(+)-ICDH gene (icdA)-overexpressing strain (OPI-1) using Aspergillus niger WU-2223L as a host and examined the effects of increase in NADP(+)-ICDH activity on citric acid production. Under citric acid-producing conditions with glucose as the carbon source, the amounts of citric acid produced and glucose consumed by OPI-1 for the 12-d cultivation period decreased by 18.7 and 10.5%, respectively, compared with those by WU-2223L. These results indicate that the amount of citric acid produced by A. niger can be altered with the NADP(+)-ICDH activity. Therefore, NADP(+)-ICDH is an important regulator of citric acid production in the TCA cycle of A. niger. Thus, we propose that the icdA gene is a potentially valuable tool for modulating citric acid production by metabolic engineering.

Crystal and molecular structure of adduct of 6-benzylaminopurine and 5-sulfosalicylic acid

Energy Technology Data Exchange (ETDEWEB)

Xia Min, E-mail: xiamin@hytc.edu.cn; Ma Kuirong [Huaiyin Normal University, Jiangsu Key Laboratory for Chemistry of Low-Dimensional Materials, School of Chemistry and Chemical Engineering (China)

2010-12-15

The crystal structure of adduct of 6-benzylaminopurine and 5-sulfosalicylic acid C{sub 19}H{sub 25}N{sub 5}O{sub 10}S 1 is studied using single-crystal diffraction (R = 0.0482 for 2852 reflections with I > 2{sigma}(I)). The asymmetric unit of 1 contains one 6-benzylaminopurine molecule and one 5-sulfosalicylic acid molecule, as well as four lattice water molecules. Hydrogen bonds, formed by 6-benzylaminopurine and 5-sulfosalicylic acid, link the two molecules into one-dimensional chain (omitting four water molecules), further joined to two-dimensional layer network. Short ring-interactions with intra-chain {pi}-{pi} stacking are observed. The data of IR spectroscopy confirm the formation of the two-dimensional supramolecular layer structure. At last, a 3D supramolecular network constructs via hydrogen bonds.

Inhibitors of bacterial N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) and demonstration of in vitro antimicrobial activity.

Science.gov (United States)

Gillner, Danuta; Armoush, Nicola; Holz, Richard C; Becker, Daniel P

2009-11-15

The dapE-encoded N-succinyl-L,L-diaminopimelic acid desuccinylase (DapE) is a critical bacterial enzyme for the construction of the bacterial cell wall. A screen biased toward compounds containing zinc-binding groups (ZBG's) including thiols, carboxylic acids, boronic acids, phosphonates and hydroxamates has delivered a number of micromolar inhibitors of DapE from Haemophilus influenzae, including the low micromolar inhibitor L-captopril (IC(50)=3.3 microM, K(i)=1.8 microM). In vitro antimicrobial activity was demonstrated for L-captopril against Escherichia coli.

Constructive renormalization theory

International Nuclear Information System (INIS)

Rivasseau, Vincent

2000-01-01

These notes are the second part of a common course on Renormalization Theory given with Professor P. da Veiga. I emphasize here the rigorous non-perturbative or constructive aspects of the theory. The usual formalism for the renormalization group in field theory or statistical mechanics is reviewed, together with its limits. The constructive formalism is introduced step by step. Taylor forest formulas allow to perform easily the cluster and Mayer expansions which are needed for a single step of the renormalization group in the case of Bosonic theories. The iteration of this single step leads to further difficulties whose solution is briefly sketched. The second part of the course is devoted to Fermionic models. These models are easier to treat on the constructive level so they are very well suited to beginners in constructive theory. It is shown how the Taylor forest formulas allow to reorganize perturbation theory nicely in order to construct the Gross-Neveu 2 model without any need for cluster or Mayer expansions. Finally applications of this technique to condensed matter and renormalization group around Fermi surface are briefly reviewed. (author)

Why developmental niche construction is not selective niche construction: and why it matters.

Science.gov (United States)

Stotz, Karola

2017-10-06

In the last decade, niche construction has been heralded as the neglected process in evolution. But niche construction is just one way in which the organism's interaction with and construction of the environment can have potential evolutionary significance. The constructed environment does not just select for , it also produces new variation. Nearly 3 decades ago, and in parallel with Odling-Smee's article 'Niche-constructing phenotypes', West and King introduced the 'ontogenetic niche' to give the phenomena of exo genetic inheritance a formal name. Since then, a range of fields in the life sciences and medicine has amassed evidence that parents influence their offspring by means other than DNA (parental effects), and proposed mechanisms for how heritable variation can be environmentally induced and developmentally regulated. The concept of 'developmental niche construction' (DNC) elucidates how a diverse range of mechanisms contributes to the transgenerational transfer of developmental resources. My most central of claims is that whereas the selective niche of niche construction theory is primarily used to explain the active role of the organism in its selective environment, DNC is meant to indicate the active role of the organism in its developmental environment. The paper highlights the differences between the construction of the selective and the developmental niche, and explores the overall significance of DNC for evolutionary theory.

SUBSURFACE CONSTRUCTION AND DEVELOPMENT ANALYSIS

International Nuclear Information System (INIS)

N.E. Kramer

1998-01-01

The purpose of this analysis is to identify appropriate construction methods and develop a feasible approach for construction and development of the repository subsurface facilities. The objective of this analysis is to support development of the subsurface repository layout for License Application (LA) design. The scope of the analysis for construction and development of the subsurface Repository facilities covers: (1) Excavation methods, including application of knowledge gained from construction of the Exploratory Studies Facility (ESF). (2) Muck removal from excavation headings to the surface. This task will examine ways of preventing interference with other subsurface construction activities. (3) The logistics and equipment for the construction and development rail haulage systems. (4) Impact of ground support installation on excavation and other construction activities. (5) Examination of how drift mapping will be accomplished. (6) Men and materials handling. (7) Installation and removal of construction utilities and ventilation systems. (8) Equipping and finishing of the emplacement drift mains and access ramps to fulfill waste emplacement operational needs. (9) Emplacement drift and access mains and ramps commissioning prior to handover for emplacement operations. (10) Examination of ways to structure the contracts for construction of the repository. (11) Discussion of different construction schemes and how to minimize the schedule risks implicit in those schemes. (12) Surface facilities needed for subsurface construction activities

Features of the low-power charge controller of lead-acid current sources charged by solar batteries

International Nuclear Information System (INIS)

Tukfatullin, O.F.; Yuldoshev, I.A.; Solieva, N.A.

2008-01-01

Influence of different factors on exploitations characteristics of solar photoelectric plant is investigated by field-performance data. A construction of charge controller of the lead-acid accumulator battery charging by means of solar battery is analyzed taking into account these factors. (authors)

Construction program management

CERN Document Server

Delaney, Joseph

2013-01-01

Although construction is one of the largest industries in the United States, it lags behind other industries in its implementation of modern management techniques such as those contained in the Standard for Program Management (the Standard) by the Project Management Institute (PMI(R)). Construction Program Management details the successful use of the PMI(R) approach for the construction of capital programs. It demonstrates, through case studies, how implementation of PMI's set of tools and techniques can improve the chances of program success. Exploring tactical and strategic management method

CONSTRUCTIVE EDUCATIONAL ENVIRONMENT SCHOOL-UNIVERSITY

Directory of Open Access Journals (Sweden)

Natalya Petrovna Shatalova

2016-02-01

Full Text Available The article presents the results of the study the key components of the development of constructive thinking of students on the basis of model building constructive educational environment school-University. It was conducted from a position of constructive approach in education, as a process of systemic-structural methodology of cognitive and creative activity of the student, promotes development and formation of various constructive qualities of the individual. The functions of constructive educational environment school-University aimed at developing constructive thinking of students, defined by its structural components and connections, shows the consistency of self-development of constructive thinking and job satisfaction the development of constructive skills. The findings reveal innovative possibilities of cooperation of schools and universities in the design and functioning model of constructive educatio-nal space that contributes to the development of constructive thinking of all its stakeholders.Purpose: measuring the effectiveness of the model constructive educational environment school-University aimed at the development of students.Methodology: the Programme of research included: (1 diagnosis of the development level of constructive thinking on the questionnaire developed in the context of the constructive theory of education, (2 augmented and revised by the author the diagnosis of satisfaction and importance model of constructive educational environment school-University by the method of G.A. Gagarin, as well as theoretical modeling, method of involved observation, formal teaching method.Results. The article introduces the concept of «constructive learning environments», which are considered in relation to the organization and conduct of joint activities of teachers, teachers and students. The authors give a theoretical comparative analysis of scientific works of colleagues in the context of the problem. Offer a brief

49 CFR 1101.3 - Construction.

Science.gov (United States)

2010-10-01

... 49 Transportation 8 2010-10-01 2010-10-01 false Construction. 1101.3 Section 1101.3 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION RULES OF PRACTICE DEFINITIONS AND CONSTRUCTION § 1101.3 Construction. The rules of construction...

Mathematical simulation of equilibria in the Pr(3) chloride-iminodiacetic acid - cation exchange resin system

Energy Technology Data Exchange (ETDEWEB)

Kupriyanova, G.N.; Krivenko, S.V.; Martynenko, L.I.; Evseev, A.M.; Spitsyn, V.I. (Moskovskij Gosudarstvennyj Univ. (USSR))

1982-01-01

Multiresponse adequate mathematical model is constructed that describes the composition of phases in the complex ion exchange system r.e.e. (PrCl/sub 3/)-complexon (iminodiacetic acid)-cationite-H/sub 2/O-KOH. The model is constructed on the basis of the law of acting masses in combination with equations of material balance and electroneutrality equations. The considerable effect on the state of the sorption system of metal complexonates is proved. The account of absorption of praseodymium iminodiacetates is necessary for complete description of the system and control of chromatographic process.

Radioactive materials in construction projects

International Nuclear Information System (INIS)

Herrmann, Ralf; Ohlendorf, Frank; Kaltz, Andrea Christine

2014-01-01

Till 1990 residues often of the former uranium mining were partly used as building material for road construction, terrain compensation and house construction in Saxony. These recommendations for action are addressed to applicants, planners and building constructors in the engineering and construction sector. It provides information for planning, preliminary investigations, applications, construction supervision related to radiation protection measures and documentation of construction projects where radioactive materials are expected.

Fatty acids and survival of bacteria in Hammam Pharaon springs, Egypt

Directory of Open Access Journals (Sweden)

Yehia A. Osman

2018-06-01

Full Text Available A great lack of knowledge of Hammam Pharaon's microbial community; the most famous hot spring in Sinai, Egypt, derived this work. Three different hyperthermophilic bacterial were isolated from vents in the area, where the temperature was above 80 °C. Response Surface Methodology algorithm such as Central Composite Design determined the optimum cultivation conditions for these isolates. Accordingly, the best growth conditions were at 70 °C and at neutral to slightly acidic pH values. The constructed phylogenetic tree built using the 16S rRNA gene sequences has shown that the isolated strains (HM101, HM102 and HM103 belong to Geobacillus, Rhodothermus and Thermus bacteria, respectively. The fatty acid profiles, an indicative of thermotolerance, dominated by the short chain Dodecanoic acid (Lauric acid; (12:0, which represented about 40% of the total fatty acid contents for each of the three isolates. The enzymatic capabilities of the three strains were determined and α-amylase was found to be the most prominent one. Our own data had led us to conclude that the length of the fatty acid chain and the degree of saturation could be species specific. Moreover, the biotechnological potentials of these local isolates could contribute to fighting viral diseases and/or improve their amylolytic activities for sugar industry; where thermotolerance is really an important factor.

Mass transfer during sulfuric acid concentration by evaporation into the air flow

Directory of Open Access Journals (Sweden)

V. K. Lukashov

2016-12-01

Full Text Available This article shows the results of the study of mass transfer under periodic concentration of sulfuric acid by evaporation inthe gas flow, neutral with respect to the components of acid.Used mathematical model for mass transferbases on the proposed simplified physical representations.This model has allowed to construct an algorithm for calculation the coefficient of mass transfer from the liquid phase into the gas flow. The algorithm uses the experimental data of change the amount of acid and concentration of the water taken from the laboratory tests. Time-based Nusselt diffusion criterion represent the results of the study at different modes of the evaporation process.It has been found that the character of the influence of temperature and initial acid concentration on Nusselt diffusion criterion depends on the variation range of the mass fraction of water in the acid.It is shown that these dependences are well approximated by an exponential function from the dimensionless parameters of the process. This allows usingthem for calculation the mass transfer coefficient into the gas phase in a batch process of concentrating in the range of investigated modes.

Human Resource Construction

Institute of Scientific and Technical Information of China (English)

2015-01-01

Centering on strategic objective of reform and development,CIAE formulated its objectives in human resource construction for the 13th Five-year Plan period,and achieved new apparent progress in human resource construction in 2015.1 Implementation of"LONGMA Project"

Personal Usability Constructs

DEFF Research Database (Denmark)

Hertzum, Morten; Clemmensen, Torkil; Hornbæk, Kasper

2011-01-01

Whereas the concept of usability is predominantly defined analytically, people relate to systems through personal usability constructs. Based on 48 repertory-grid interviews, this study investigates how such personal constructs are affected by two factors crucial to the international development...

Periodontal regeneration using a bilayered PLGA/calcium phosphate construct.

Science.gov (United States)

Carlo Reis, Emily C; Borges, Andréa P B; Araújo, Michel V F; Mendes, Vanessa C; Guan, Limin; Davies, John E

2011-12-01

The regeneration of tissues affected by periodontal disease is a complex process; it encompasses the formation of bone, cementum and periodontal ligament. We developed a semi-rigid PLGA (polylactide-co-glycolide acid)/CaP (calcium phosphate) bilayered biomaterial construct to promote periodontal regeneration, which has a continuous outer barrier membrane and an inner topographically complex component. Our experimental model compared periodontal prophylaxis alone with prophylaxis and biomaterial implantation in the treatment of class II furcation defects in dogs. Clinical evaluation, micro-computed tomography, histology and backscattered electron imaging were used for data analysis. Healing occurred uneventfully and bone volumetric values, trabecular number and trabecular thickness were all significantly greater in the treated group; while trabecular separation was significantly greater in the control group. New cementum, bone, and periodontal ligament with Sharpey fibre insertions were only seen in the treated group. Although periodontal regeneration has been reported elsewhere, the advantages of employing our bilayered PLGA + CaP construct are twofold: 1)it did not collapse into the defect; and, 2) its inner side was able to retain the blood clot throughout the buccal defect. The result was greater periodontal regeneration than has previously been reported with traditional flexible membranes. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sustainable construction : towards a strategic approach to construction material management for waste reduction

NARCIS (Netherlands)

Abarca Guerrero, L.; Scheublin, F.J.M.; Egmond - de Wilde De Ligny, van E.L.C.; Lambert, A.J.D.

2008-01-01

The construction sector plays a key role in shaping and developing the built environment. It also has an undisputed and significant impact on it due to the amounts of materials extracted and produced as waste. The construction industry has emphasized to recycling construction waste (CW), however,

DECISION SUPPORT CONCEPT TO MANAGEMENT OF CONSTRUCTION PROJECTS - PROBLEM OF CONSTRUCTION SITE SELECTION

Directory of Open Access Journals (Sweden)

Nikša Jajac

2013-02-01

Full Text Available The aim of this paper is to present Decision Support Concept (DSC for management of construction projects. Focus of our research is in application of multicritera methods (MCM to decision making in planning phase of construction projects (related to the problem of construction sites selection. The problem is identified as a significant one from many different aspects such as economic aspect, civil engineering aspect, etc. what indicates the necessity for evaluation of multiple sites by several different criteria. Therefore, DSC for construction site selection based on PROMETHEE method is designed. In order to define the appropriate criteria, their weights and preference functions for the concept, three groups of stakeholders are involved (investors, construction experts and experts for real estate market in its design. AHP method has been used for determination of criteria weights. The model has been tested on the problem of site selection for construction of residential-commercial building in four largest cities in Croatia.

Modeling and simulation of enzymatic gluconic acid production using immobilized enzyme and CSTR-PFTR circulation reaction system.

Science.gov (United States)

Li, Can; Lin, Jianqun; Gao, Ling; Lin, Huibin; Lin, Jianqiang

2018-04-01

Production of gluconic acid by using immobilized enzyme and continuous stirred tank reactor-plug flow tubular reactor (CSTR-PFTR) circulation reaction system. A production system is constructed for gluconic acid production, which consists of a continuous stirred tank reactor (CSTR) for pH control and liquid storage and a plug flow tubular reactor (PFTR) filled with immobilized glucose oxidase (GOD) for gluconic acid production. Mathematical model is developed for this production system and simulation is made for the enzymatic reaction process. The pH inhibition effect on GOD is modeled by using a bell-type curve. Gluconic acid can be efficiently produced by using the reaction system and the mathematical model developed for this system can simulate and predict the process well.

Construction in Occupied Spaces

Directory of Open Access Journals (Sweden)

Ward Andrew E.

2017-06-01

Full Text Available Conducting construction activities in occupied environments presents a great challenge due to the additional logistical requirements and the presence of the building occupants. The aim of this research is to gather and evaluate the means and methods to successfully plan, manage, and execute construction activities in occupied spaces in an effort to provide consolidated industry tools and strategies for maintaining a schedule and minimizing the impact on the occupants. The methodology of the research utilizes an exploratory approach to gather qualitative data. The data was collected through interviews with industry professionals to identify industry best practices. The semi-structured interviews provided a platform for the documents, lessons learned, and the techniques and strategies used for occupied construction by the construction industry. The information obtained in the interview process identified six themes that are critical to achieving and maintaining quality in occupied construction. These themes of the schedule, cost, customer satisfaction, planning, fire/life safety and utilities, and contractor management are reviewed in detail, and the paper discusses how to manage each element. The analysis and extracted management techniques, procedures and strategies can be used by the construction industry for future projects by focusing on the critical aspects of occupied construction and the manner in which to succeed with it.

Construction in Occupied Spaces

Science.gov (United States)

Ward, Andrew E.; Azhar, Salman; Khalfan, Malik

2017-06-01

Conducting construction activities in occupied environments presents a great challenge due to the additional logistical requirements and the presence of the building occupants. The aim of this research is to gather and evaluate the means and methods to successfully plan, manage, and execute construction activities in occupied spaces in an effort to provide consolidated industry tools and strategies for maintaining a schedule and minimizing the impact on the occupants. The methodology of the research utilizes an exploratory approach to gather qualitative data. The data was collected through interviews with industry professionals to identify industry best practices. The semi-structured interviews provided a platform for the documents, lessons learned, and the techniques and strategies used for occupied construction by the construction industry. The information obtained in the interview process identified six themes that are critical to achieving and maintaining quality in occupied construction. These themes of the schedule, cost, customer satisfaction, planning, fire/life safety and utilities, and contractor management are reviewed in detail, and the paper discusses how to manage each element. The analysis and extracted management techniques, procedures and strategies can be used by the construction industry for future projects by focusing on the critical aspects of occupied construction and the manner in which to succeed with it.

The pH ruler: a Java applet for developing interactive exercises on acids and bases.

Science.gov (United States)

Barrette-Ng, Isabelle H

2011-07-01

In introductory biochemistry courses, it is often a struggle to teach the basic concepts of acid-base chemistry in a manner that is relevant to biological systems. To help students gain a more intuitive and visual understanding of abstract acid-base concepts, a simple graphical construct called the pH ruler Java applet was developed. The applet allows students to visualize the abundance of different protonation states of diprotic and triprotic amino acids at different pH values. Using the applet, the student can drag a widget on a slider bar to change the pH and observe in real time changes in the abundance of different ionization states of this amino acid. This tool provides a means for developing more complex inquiry-based, active-learning exercises to teach more advanced topics of biochemistry, such as protein purification, protein structure and enzyme mechanism.

The growth rate of pyrimidine auxotrophic mutants of Lactococcus lactis MG1363 is reduced in the presence of exogenous aspartate

DEFF Research Database (Denmark)

Hansen, Steen Lyders Lerche; Martinussen, Jan

1998-01-01

Nucleotide metabolism is important for all cells as supplier of building blocks for the synthesis of nucleic acids and coenzymes. Furthermore, they act as intracellular energy carriers and allosteric effectors in a large number of enzymatic reactions. Nucleotides can either be made de novo or from...... encoding enzymes in the distal part of the pyrimidine biosynthetic pathway of L. lactis MG1363, results in reduction of the growth rate if exogenous aspartate is supplied to the growth medium. This observation can be explained by an increased accumulation of a toxic intermediate, most likely carbamoyl...... aspartate, provoked by high concentrations of aspartate....

The acidic functional groups of humic acid

Energy Technology Data Exchange (ETDEWEB)

Shanxiang, Li; Shuhe, Sun; Zhai Zongxi, Wu Qihu

1983-09-01

The acidic functional groups content, pK value, DELTAH and DELTAS of humic acid (HA) and nitro-humic acid (NHA) were determined by potentiometry, conductometry and calorimetric titration. The thermodynamic parameters of carboxylic groups and phenolic hydroxyl groups of humic acid are similar to that of simple hydroxy-benzoic acid. The configuration sites of acidic functional groups in humic acid from different coals are different. The carbonyl groups on aromatic rings are probably ortho to phenolic -OH for HA and NHA extracted from Huangxian's brown coal and Japanese lignite, while those from Lingshi's weathered coal are not. The weak -COOH groups of the latter possess higher chemical activity. The -COOH content in HA increases, phenolic -OH group decreases and the chemical acidity of acidic functional groups increases when HA is oxidized by nitric acid. (14 refs.)

Evaluating the efficacy of a structure-derived amino acid substitution matrix in detecting protein homologs by BLAST and PSI-BLAST.

Science.gov (United States)

Goonesekere, Nalin Cw

2009-01-01

The large numbers of protein sequences generated by whole genome sequencing projects require rapid and accurate methods of annotation. The detection of homology through computational sequence analysis is a powerful tool in determining the complex evolutionary and functional relationships that exist between proteins. Homology search algorithms employ amino acid substitution matrices to detect similarity between proteins sequences. The substitution matrices in common use today are constructed using sequences aligned without reference to protein structure. Here we present amino acid substitution matrices constructed from the alignment of a large number of protein domain structures from the structural classification of proteins (SCOP) database. We show that when incorporated into the homology search algorithms BLAST and PSI-blast, the structure-based substitution matrices enhance the efficacy of detecting remote homologs.

AP1000 construction schedule

International Nuclear Information System (INIS)

Winters, J.W.

2001-01-01

Westinghouse performed this study as part of EPRI interest in advancing the use of computer aided processes to reduce the cost of nuclear power plants. EPRI believed that if one could relate appropriate portions of an advanced light water reactor plant model to activities in its construction sequence, and this relationship could be portrayed visually, then optimization of the construction sequence could be developed as never before. By seeing a 3-D representation of the plant at any point in its construction sequence, more informed decisions can be made on the feasibility or attractiveness of follow on or parallel steps in the sequence. The 3-D representation of construction as a function of time (4-D) could also increase the confidence of potential investors concerning the viability of the schedule and the plant ultimate cost. This study performed by Westinghouse confirmed that it is useful to be able to visualize a plant construction in 3-D as a function of time in order to optimize the sequence of construction activities. (author)

Characterization and Strain Improvement of a Hypercellulytic Variant, Trichoderma reesei SN1, by Genetic Engineering for Optimized Cellulase Production in Biomass Conversion Improvement.

Science.gov (United States)

Qian, Yuanchao; Zhong, Lixia; Hou, Yunhua; Qu, Yinbo; Zhong, Yaohua

2016-01-01

The filamentous fungus Trichoderma reesei is a widely used strain for cellulolytic enzyme production. A hypercellulolytic T. reesei variant SN1 was identified in this study and found to be different from the well-known cellulase producers QM9414 and RUT-C30. The cellulose-degrading enzymes of T. reesei SN1 show higher endoglucanase (EG) activity but lower β-glucosidase (BGL) activity than those of the others. A uracil auxotroph strain, SP4, was constructed by pyr4 deletion in SN1 to improve transformation efficiency. The BGL1-encoding gene bgl1 under the control of a modified cbh1 promoter was overexpressed in SP4. A transformant, SPB2, with four additional copies of bgl1 exhibited a 17.1-fold increase in BGL activity and a 30.0% increase in filter paper activity. Saccharification of corncob residues with crude enzyme showed that the glucose yield of SPB2 is 65.0% higher than that of SP4. These results reveal the feasibility of strain improvement through the development of an efficient genetic transformation platform to construct a balanced cellulase system for biomass conversion.

Characterization and strain improvement of a hypercellulytic variant, Trichoderma reesei SN1, by genetic engineering for optimized cellulase production in biomass conversion improvement

Directory of Open Access Journals (Sweden)

Qian Yuanchao

2016-08-01

Full Text Available The filamentous fungus Trichoderma reesei is a widely used strain for cellulolytic enzyme production. A hypercellulolytic T. reesei variant SN1 was identified in this study and found to be different from the well-known cellulase producers QM9414 and RUT-C30. The cellulose-degrading enzymes of T. reesei SN1 show higher endoglucanase (EG activity but lower β-glucosidase (BGL activity than those of QM9414 and RUT-C30. A uracil auxotroph strain, SP4, was constructed by pyr4 deletion in SN1 to improve transformation efficiency. The BGL1-encoding gene bgl1 under the control of a modified cbh1 promoter was overexpressed in SP4. A transformant, SPB2, with four additional copies of bgl1 exhibited a 17.1-fold increase in BGL activity and a 30% increase in filter paper activity. Saccharification of corncob residues with crude enzyme showed that the glucose yield of SPB2 is 65% higher than that of SP4. These results reveal the feasibility of strain improvement through the development of an efficient genetic transformation platform to construct a balanced cellulase system for biomass conversion.

ABWR construction experience in Japan

International Nuclear Information System (INIS)

Kawahata, Junichi; Miura, Jun; Saito, Fuyuki; Mori, Hiroya

2003-01-01

The construction of Kashiwazaki-Kariwa Nuclear Power Station Unit No. 6 and 7 (K6 and 7) owned by Tokyo Electric Power Company (TEPCO), have been in service since November 1996 and September 1997 respectively, and are the first ABWRs in the world. Hitachi, Ltd. and Toshiba Corporation took part in the projects and achieved safety construction in 52- month schedule from rock inspection to turnover in cooperation with TEPCO and other contractors with broad experience in BWRs. Taking advantage of experience of the Kashiwazaki construction, the ABWR construction methods realize to satisfy with requests from electric power companies and to fit site conditions. The Chubu Electric Power Company's Hamaoka Nuclear Power Station Unit No. 5 (Hamaoka 5) and Hokuriku Electric Power Company's Shika Nuclear Power Station Unit No. 2 (Shika 2), which are ABWRs, completed rock inspection in May 2000 and June 2001 respectively, and are under construction. The ABWR construction methods are proved their validity through four actual construction projects. Safe constructions with the highest quality have been advanced thus further aiming at the introduction of the latest technologies and contributing to reduce plant construction costs and also to shorten schedule. (author)

Safety in construction?

NARCIS (Netherlands)

Swuste, P.H.J.J.

2013-01-01

The available literature on Construction Safety is not very optimistic about the chances of evidence-based safety in the construction industry exerting a positive influence. Many articles indicate that the structures and processes that are designed to ensure safety in the industry are poor. Safety

Syntheses and structure characterization of ten acid-base hybrid crystals based on N-containing aromatic brønsted bases and mineral acids

Science.gov (United States)

Lin, Zhihao; Jin, Shouwen; Li, Xiaoliang; Xiao, Xiao; Hu, Kaikai; Guo, Ming; Chi, Xinchen; Liu, Hui; Wang, Daqi

2017-10-01

Cocrystallization of the aromatic brønsted bases with a series of mineral acids gave a total of ten hybrid salts with the compositions: (2-methylquinoline)2: (hydrochloride acid): 3H2O [(HL1)+. (L1)·· (Cl-) · (H2O)3] (1), (6-bromobenzo[d]thiazol-2-amine): (hydrochloride acid) [(HL2)+. (Cl-)] (2), (6-bromobenzo[d]thiazol-2-amine): (nitric acid) [(HL2)+. (NO3-)] (3), (6-bromobenzo[d]thiazol-2-amine): (sulfuric acid) [(HL2)+ · (HSO4)-] (4), (6-bromobenzo[d]thiazol-2-amine): (phosphoric acid) [(HL2)+ · (H2PO4)-] (5), (5,7-dimethyl-1,8-naphthyridine-2-amine): (hydrochloride acid): 3H2O [(HL3)+ · (Cl-) (H2O)3] (6), (5,7-dimethyl-1,8-naphthyridine-2-amine): (hydrobromic acid): CH3OH [(HL3)+ · (Br)- · CH3OH] (7), (5,7-dimethyl-1,8-naphthyridine-2-amine): (sulfuric acid): H2O [(HL3)+ · (HSO4)- · H2O] (8), (2-aminophenol): (phosphoric acid) [(HL4)+ · (H2PO4)-] (9), and (2-amino-4-chlorophenol): (phosphoric acid) [(HL5)+ · (H2PO4)-] (10). The ten salts have been characterized by X-ray diffraction analysis, IR, and elemental analysis, and the melting points of all the salts were also reported. And their structural and supramolecular aspects are fully analyzed. The result reveals that among the ten investigated crystals the ring N of the heterocycle or the NH2 in the aminophenol are protonated when the acids are deprotonated, and the crystal packing is interpreted in terms of the strong charge-assisted classical hydrogen bonds between the NH+/NH3+ and deprotonated acidic groups. Further analysis of the crystal packing of the salts indicated that a different family of additional CHsbnd O, CHsbnd Cl, CH3sbnd N, CH3sbnd O, CHsbnd Br, CH3sbnd Br, Brsbnd Cl, Clsbnd S, Osbnd S, Osbnd O, Brsbnd S, Hsbnd H, and π-π associations contribute to the stabilization and expansion of the total high-dimensional frameworks. For the coexistence of the various weak nonbonding interactions these structures adopted homo or hetero supramolecular synthons or both. Some classical

Polyesters production from the mixture of phthalic acid, terephthalic and glycerol

International Nuclear Information System (INIS)

Carvalho, A.L.S.; Oliveira, J.C.; Miranda, C.S.; Boaventura, J.S.; Jose, N.M.; Carvalho, R.F.

2010-01-01

Glycerin, a byproduct of biodiesel is currently an environmental and economic problem for producers of this renewable fuel in Brazil and in others parts of the world. In order to offer new proposals for recovery, it is used for the manufacture of polyesters used in applications in diverse areas such as construction and automobile industry. This work reports the production of polymer from the mixture of terephthalic and phthalic acid in three different proportions. The polyesters showed good thermal stability, analyzed by TGA and DSC, with an increase proportional to the terephthalic acid content. The X-ray diffraction patterns show that the samples are semi crystalline polymers. The micrographs indicated the presence of a smoother surface in the polyester that has a larger amount of phthalic acid, as reported in the literature. Therefore, the materials showed good thermal properties and morphological characteristics, so it consists in a new alternative to use glycerin. (author)

Construction Safety Forecast for ITER

Energy Technology Data Exchange (ETDEWEB)

cadwallader, lee charles

2006-11-01

The International Thermonuclear Experimental Reactor (ITER) project is poised to begin its construction activity. This paper gives an estimate of construction safety as if the experiment was being built in the United States. This estimate of construction injuries and potential fatalities serves as a useful forecast of what can be expected for construction of such a major facility in any country. These data should be considered by the ITER International Team as it plans for safety during the construction phase. Based on average U.S. construction rates, ITER may expect a lost workday case rate of < 4.0 and a fatality count of 0.5 to 0.9 persons per year.

Innovations in nuclear concrete constructions

International Nuclear Information System (INIS)

Tatum, C.B.

1983-01-01

The technical requirements and scope of concrete work on nuclear projects present significant engineering and construction challenges. These demands represent the extremes in many areas of construction operations. In meeting these challenges, engineering and construction forces have developed several innovations which can be beneficially applied to other types of construction. Innovative approaches in the general categories of engineering scope, construction input to engineering, work planning, special methods and techniques, and satisfaction of quality assurance requirements are given in this paper. The transfer of this technology to other segments of the construction industry will improve overall performance by avoiding the problem areas encountered on nuclear projects

23 CFR 140.607 - Construction.

Science.gov (United States)

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Construction. 140.607 Section 140.607 Highways FEDERAL... Bond Issue Projects § 140.607 Construction. Construction shall be supervised by the SHA in the same manner as for regularly financed Federal-aid projects. The FHWA will make construction inspections and...

Production of extracellular fatty acid using engineered Escherichia coli

Directory of Open Access Journals (Sweden)

Liu Hui

2012-04-01

Full Text Available Abstract Background As an alternative for economic biodiesel production, the microbial production of extracellular fatty acid from renewable resources is receiving more concerns recently, since the separation of fatty acid from microorganism cells is normally involved in a series of energy-intensive steps. Many attempts have been made to construct fatty acid producing strains by targeting genes in the fatty acid biosynthetic pathway, while few studies focused on the cultivation process and the mass transfer kinetics. Results In this study, both strain improvements and cultivation process strategies were applied to increase extracellular fatty acid production by engineered Escherichia coli. Our results showed overexpressing ‘TesA and the deletion of fadL in E. coli BL21 (DE3 improved extracellular fatty acid production, while deletion of fadD didn’t strengthen the extracellular fatty acid production for an undetermined mechanism. Moreover, the cultivation process controls contributed greatly to extracellular fatty acid production with respect to titer, cell growth and productivity by adjusting the temperature, adding ampicillin and employing on-line extraction. Under optimal conditions, the E. coli strain (pACY-‘tesA-ΔfadL produced 4.8 g L−1 extracellular fatty acid, with the specific productivity of 0.02 g h−1 g−1dry cell mass, and the yield of 4.4% on glucose, while the ratios of cell-associated fatty acid versus extracellular fatty acid were kept below 0.5 after 15 h of cultivation. The fatty acids included C12:1, C12:0, C14:1, C14:0, C16:1, C16:0, C18:1, C18:0. The composition was dominated by C14 and C16 saturated and unsaturated fatty acids. Using the strain pACY-‘tesA, similar results appeared under the same culture conditions and the titer was also much higher than that ever reported previously, which suggested that the supposedly superior strain did not necessarily perform best for the efficient production of desired

25 CFR 900.118 - Do these “construction contract” regulations apply to construction management services?

Science.gov (United States)

2010-04-01

... construction management services? 900.118 Section 900.118 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE...” regulations apply to construction management services? No. Construction management services may be contracted separately under section 108 of the Act. Construction management services consultants and/or Indian tribe or...

The Acid-Base Titration of a Very Weak Acid: Boric Acid

Science.gov (United States)

Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

2012-01-01

A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

Binary and ternary solid-liquid phase equilibrium for the systems formed by succinic acid, urea and diethylene glycol: Determination and modelling

International Nuclear Information System (INIS)

Li, Yanxun; Li, Congcong; Han, Shuo; Zhao, Hongkun

2017-01-01

Highlights: • Solubility of succinic acid in diethylene glycol was determined. • Solubility of succinic acid + urea + diethylene glycol was determined. • Three ternary phase diagrams were constructed for the ternary system. • The ternary phase diagrams were correlated using NRTL model. - Abstract: In this work, the solid-liquid phase equilibrium for binary system of succinic acid + diethylene glycol at the temperatures ranging from (298.15 to 333.15) K and ternary system of (succinic acid + urea + diethylene glycol) at 298.15 K, 313.15 K and 333.15 K was built by using the isothermal saturation method under atmospheric pressure (101.2 kPa), and the solubilities were determined by a high-performance liquid chromatography. The solid-phases formed in the ternary system of ((succinic acid + urea + diethylene glycol)) were confirmed by Schreinemaker’s method of wet residue, which corresponded to urea, succinic acid, and adduct 2:1 urea-succinic acid (mole ratio). Three isothermal phase diagrams for the ternary system were constructed based on the measured mutual solubility. Each isothermal phase diagram included six crystallization fields, three invariant curves, two invariant points and two co-saturated points. The crystalline region of adduct 2:1 urea-succinic acid is larger than those of the other two solids. The solubility of succinic acid in diethylene glycol was correlated with the modified Apelblat equation, λh equation and NRTL model; and the mutual solubility of the ternary ((succinic acid + urea + diethylene glycol)) system was correlated and calculated by the NRTL model. The interaction parameters’ values of succinic acid-urea were acquired. The value of RMSD was 7.11 × 10 −3 for the ternary system. The calculation results had good agreement with the experiment values. Furthermore, the densities of equilibrium liquid phase were acquired. The phase diagrams and the thermodynamic model of the ternary system could provide the basis for design of

Morphological regulation of Aspergillus niger to improve citric acid production by chsC gene silencing.

Science.gov (United States)

Sun, Xiaowen; Wu, Hefang; Zhao, Genhai; Li, Zhemin; Wu, Xihua; Liu, Hui; Zheng, Zhiming

2018-04-02

The mycelial morphology of Aspergillus niger, a major filamentous fungus used for citric acid production, is important for citric acid synthesis during submerged fermentation. To investigate the involvement of the chitin synthase gene, chsC, in morphogenesis and citric acid production in A. niger, an RNAi system was constructed to silence chsC and the morphological mutants were screened after transformation. The compactness of the mycelial pellets was obviously reduced in the morphological mutants, with lower proportion of dispersed mycelia. These morphological changes have caused a decrease in viscosity and subsequent improvement in oxygen and mass transfer efficiency, which may be conducive for citric acid accumulation. All the transformants exhibited improvements in citric acid production; in particular, chsC-3 showed 42.6% higher production than the original strain in the shake flask. Moreover, the high-yield strain chsC-3 exhibited excellent citric acid production potential in the scale-up process.The citric acid yield and the conversion rate of glucose of chsC-3 were both improved by 3.6%, when compared with that of the original strain in the stirred tank bioreactor.

PRIORITISING LEAN CONSTRUCTION BARRIERS IN UGANDA'S CONSTRUCTION INDUSTRY

Directory of Open Access Journals (Sweden)

Henry Mwanaki Alinaitwe

2009-06-01

Full Text Available Engaging in lean construction efforts could prove to be highly rewarding for building firms in Uganda. However, lean construction is risky and can be disastrous if not properly managed. Lean production efforts in some other countries have not been successful due to the many barriers to its successful implementation. To enable sound lean construction efforts and to increase the chances of success in eliminating waste, a thorough investigation of the barriers is essential. This study presents 31 barriers and investigates their influence (strength on the success of lean construction initiatives. Structured interviews were carried out with technical managers of building firms to assess their perception of the barriers to lean production based on their experience at their firms. The strongest barrier is the provision of inputs exactly when required. Additionally, the barriers were ranked according to the ease of overcoming each. The easiest barrier to overcome is keeping the required items in the right place. Finally, a graphical aid is provided to enable decision makers to concentrate their efforts on the influential (strong, yet easy to overcome barriers. A lack of buildable designs and a participative management style for the workforce are the most important barriers to successful waste reduction in terms of strength and ease of overcoming. On the other hand, a lack of an organisational culture that supports teamwork, a lack of prefabrication and a lack of knowledgeable and skilled workers are regarded as low in strength, and at the same time difficult to overcome.

Potential for the use of hydrochloric acid in fission reactor fuel recycle

International Nuclear Information System (INIS)

Mailen, J.C.; Bell, J.T.

1985-01-01

The chemistry and the effects of the use of hydrochloric acid as the aqueous phase in fuel recycle are surveyed. Available data are sufficient to suggest that separations of actinides and fission products can be at least as good in an HCl-trialkyl amine system as in Purex. Advantages of the HCl system are simpler operations of the off-gas system, better separation of neptunium from uranium and plutonium, better control of oxidation states of the dissolved species, and simpler recycle of the acid. A possible advantage is the more complete dissolution of the fission products, leaving very little insoluble residue. Disadvantages include lack of development of methods for dissolution of oxide fuel in hydrochloric acid, the requirement for processing equipment constructed of titanium, possible complications in the waste-handling system, and the dissolution of much of the cladding in the case of stainless-steel clad fuel

Safety in construction industry

International Nuclear Information System (INIS)

Khan, A.M.

1979-01-01

Causative factors of accidents in construction industry in the context of experience of construction work of the Rajasthan Atomic Power Project are enumerated. The aspect of accident cost - direct and indirect - is discussed briefly. Setting up of a safety set-up at construction sites is emphasized and principles which should guide the accident prevention programme are spelt out. (M.G.B.)

New Amino-Acid-Based β-Phosphorylated Nitroxides for Probing Acidic pH in Biological Systems by EPR Spectroscopy.

Science.gov (United States)

Thétiot-Laurent, Sophie; Gosset, Gaëlle; Clément, Jean-Louis; Cassien, Mathieu; Mercier, Anne; Siri, Didier; Gaudel-Siri, Anouk; Rockenbauer, Antal; Culcasi, Marcel; Pietri, Sylvia

2017-02-01