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Sample records for atrezijas slimniekiem pec

  1. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  2. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  3. ACTIVE PEC APPLICATIONS, THE PEC WEBSITE, AND SLUDGE STABILITY RESEARCH

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing novel sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether these novel technolog...

  4. ACTIVE PEC APPLICATIONS, THE PEC WEBSITE, AND SLUDGE STABILITY RESEARCH

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing novel sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether these novel technolog...

  5. INTRODUCING THE FIRST EVER PEC WEBSITE

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing novel sludge disinfection technologies and their ability to protect human health and the environment. The PEC is charged to make recommendations on whether these novel technologies provide eq...

  6. INTRODUCING THE FIRST EVER PEC WEBSITE

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing novel sludge disinfection technologies and their ability to protect human health and the environment. The PEC is charged to make recommendations on whether these novel technologies provide eq...

  7. Transcriptome analysis of the Dickeya dadantii PecS regulon during early stages of interaction with Arabidopsis thaliana.

    PubMed

    Pédron, Jacques; Chapelle, Emilie; Alunni, Benoît; Van Gijsegem, Frédérique

    2017-03-15

    PecS is one of the major global regulators controlling virulence of Dickeya dadantii, a broad host range phytopathogenic bacterium causing soft rot on several plant families. To define the PecS regulon during plant colonisation, we analysed the global transcriptome profiles in wild type and pecS mutant strains during early colonization of the leaf surfaces and in leaf tissue just before the onset of symptoms and found that the PecS regulon consists of more than 600 genes. About one half of these genes are down-regulated in the pecS mutant, therefore PecS has both positive and negative regulatory roles that may be direct or indirect. Indeed, PecS also controls the regulation of a few dozen regulatory genes demonstrating that this global regulator is at or near the top of a major regulatory cascade governing adaptation to growth in planta. Notably PecS acts mainly at the very beginning of the infection, not only for preventing virulence gene induction but also playing an active role in adaptation of the bacterium to the epiphytic habitat. Comparison of the patterns of gene expression inside leaf tissues and during early colonisation of leaf surfaces in the wild type bacterium revealed 637 genes modulated between these two environments. More than 40% of these modulated genes are part of the PecS regulon emphasizing the prominent role of PecS during plant colonisation. This article is protected by copyright. All rights reserved.

  8. Streptomyces coelicolor encodes a urate-responsive transcriptional regulator with homology to PecS from plant pathogens.

    PubMed

    Huang, Hao; Mackel, Brian J; Grove, Anne

    2013-11-01

    Many transcriptional regulators control gene activity by responding to specific ligands. Members of the multiple-antibiotic resistance regulator (MarR) family of transcriptional regulators feature prominently in this regard, and they frequently function as repressors in the absence of their cognate ligands. Plant pathogens such as Dickeya dadantii encode a MarR homolog named PecS that controls expression of a gene encoding the efflux pump PecM in addition to other virulence genes. We report here that the soil bacterium Streptomyces coelicolor also encodes a PecS homolog (SCO2647) that regulates a pecM gene (SCO2646). S. coelicolor PecS, which exists as a homodimer, binds the intergenic region between pecS and pecM genes with high affinity. Several potential PecS binding sites were found in this intergenic region. The binding of PecS to its target DNA can be efficiently attenuated by the ligand urate, which also quenches the intrinsic fluorescence of PecS, indicating a direct interaction between urate and PecS. In vivo measurement of gene expression showed that activity of pecS and pecM genes is significantly elevated after exposure of S. coelicolor cultures to urate. These results indicate that S. coelicolor PecS responds to the ligand urate by attenuated DNA binding in vitro and upregulation of gene activity in vivo. Since production of urate is associated with generation of reactive oxygen species by xanthine dehydrogenase, we propose that PecS functions under conditions of oxidative stress.

  9. pH-Dependent DNA Distortion and Repression of Gene Expression by Pectobacterium atrosepticum PecS.

    PubMed

    Deochand, Dinesh K; Meariman, Jacob K; Grove, Anne

    2016-07-15

    Transcriptional activity is exquisitely sensitive to changes in promoter DNA topology. Transcription factors may therefore control gene activity by modulating the relative positioning of -10 and -35 promoter elements. The plant pathogen Pectobacterium atrosepticum, which causes soft rot in potatoes, must alter gene expression patterns to ensure growth in planta. In the related soft-rot enterobacterium Dickeya dadantii, PecS functions as a master regulator of virulence gene expression. Here, we report that P. atrosepticum PecS controls gene activity by altering promoter DNA topology in response to pH. While PecS binds the pecS promoter with high affinity regardless of pH, it induces significant DNA distortion only at neutral pH, the pH at which the pecS promoter is repressed in vivo. At pH ∼8, DNA distortions are attenuated, and PecS no longer represses the pecS promoter. A specific histidine (H142) located in a crevice between the dimerization- and DNA-binding regions is required for pH-dependent changes in DNA distortion and repression of gene activity, and mutation of this histidine renders the mutant protein incapable of repressing the pecS promoter. We propose that protonated PecS induces a DNA conformation at neutral pH in which -10 and -35 promoter elements are suboptimally positioned for RNA polymerase binding; on deprotonation of PecS, binding is no longer associated with significant changes in DNA conformation, allowing gene expression. We suggest that this mode of gene regulation leads to differential expression of the PecS regulon in response to alkalinization of the plant apoplast.

  10. Automated Geometry assisted PEC for electron beam direct write nanolithography

    SciTech Connect

    Ocola, Leonidas E.; Gosztola, David J.; Rosenmann, Daniel; Lopez, Gerald Gabriel

    2015-12-01

    Nanoscale geometry assisted proximity effect correction (NanoPEC) is demonstrated to improve PEC for nanoscale structures over standard PEC, in terms of feature sharpness for sub-100 nm structures. The method was implemented onto an existing commercially available PEC software. Plasmonic arrays of crosses were fabricated using regular PEC and NanoPEC, and optical absorbance was measured. Results confirm that the improved sharpness of the structures leads to increased sharpness in the optical absorbance spectrum features. We also demonstrated that this method of PEC is applicable to arbitrary shaped structures beyond crosses.

  11. Isolation and characterization of polygalacturonase genes (pecA and pecB) from Aspergillus flavus.

    PubMed

    Whitehead, M P; Shieh, M T; Cleveland, T E; Cary, J W; Dean, R A

    1995-09-01

    Two genes, pecA and pecB, encoding endopolyglacturonases were cloned from a highly aggressive strain of Aspergillus flavus. The pecA gene consisted of 1,228 bp encoding a protein of 363 amino acids with a predicted molecular mass of 37.6 kDa, interrupted by two introns of 58 and 81 bp in length. Accumulation of pecA mRNA in both pectin- or glucose-grown mycelia in the highly aggressive strain matched the activity profile of a pectinase previously identified as P2c. Transformants of a weakly aggressive strain containing a functional copy of the pecA gene produced P2c in vitro, confirming that pecA encodes P2c. The coding region of pecB was determined to be 1,217 bp in length interrupted by two introns of 65 and 54 bp in length. The predicted protein of 366 amino acids had an estimated molecular mass of 38 kDa. Transcripts of this gene accumulated in mycelia grown in medium containing pectin alone, never in mycelia grown in glucose-containing medium, for both highly and weakly aggressive strains. Thus, pecB encodes the activity previously identified as P1 or P3. pecA and pecB share a high degree of sequence identity with polygalacturonase genes from Aspergillus parasiticus and Aspergillus oryzae, further establishing the close relationships between members of the A. flavus group. Conservation of intron positions in these genes also indicates that they share a common ancestor with genes encoding endopolyglacturonases of Aspergillus niger.

  12. Definition of a consensus DNA-binding site for PecS, a global regulator of virulence gene expression in Erwinia chrysanthemi and identification of new members of the PecS regulon.

    PubMed

    Rouanet, Carine; Reverchon, Sylvie; Rodionov, Dmitry A; Nasser, William

    2004-07-16

    In Erwinia chrysanthemi, production of pectic enzymes is modulated by a complex network involving several regulators. One of them, PecS, which belongs to the MarR family, also controls the synthesis of various other virulence factors, such as cellulases and indigoidine. Here, the PecS consensus-binding site is defined by combining a systematic evolution of ligands by an exponential enrichment approach and mutational analyses. The consensus consists of a 23-base pair palindromic-like sequence (C(-11)G(-10)A(-9)N(-8)W(-7)T(-6)C(-5)G(-4)T(-3)A(-2))T(-1)A(0)T(1)(T(2)A(3)C(4)G(5)A(6)N(7)N(8)N(9)C(10)G(11)). Mutational experiments revealed that (i) the palindromic organization is required for the binding of PecS, (ii) the very conserved part of the consensus (-6 to 6) allows for a specific interaction with PecS, but the presence of the relatively degenerated bases located apart significantly increases PecS affinity, (iii) the four bases G, A, T, and C are required for efficient binding of PecS, and (iv) the presence of several binding sites on the same promoter increases the affinity of PecS. This consensus is detected in the regions involved in PecS binding on the previously characterized target genes. This variable consensus is in agreement with the observation that the members of the MarR family are able to bind various DNA targets as dimers by means of a winged helix DNA-binding motif. Binding of PecS on a promoter region containing the defined consensus results in a repression of gene transcription in vitro. Preliminary scanning of the E. chrysanthemi genome sequence with the consensus revealed the presence of strong PecS-binding sites in the intergenic region between fliE and fliFGHIJKLMNOPQR which encode proteins involved in the biogenesis of flagellum. Accordingly, PecS directly represses fliE expression. Thus, PecS seems to control the synthesis of virulence factors required for the key steps of plant infection.

  13. Training Paraprofessionals to Implement the Picture Exchange Communication System (PECS)

    ERIC Educational Resources Information Center

    Sloman, Glenn Matthew

    2010-01-01

    Based on Skinner's "Verbal Behavior" (1957), the picture exchange communication system (PECS) was designed to teach children with autism functional verbal behavior. Much research has demonstrated the effectiveness and efficiency of PECS in building verbal behavior. However, because PECS training is typically presented in a group format and later…

  14. Training Paraprofessionals to Implement the Picture Exchange Communication System (PECS)

    ERIC Educational Resources Information Center

    Sloman, Glenn Matthew

    2010-01-01

    Based on Skinner's "Verbal Behavior" (1957), the picture exchange communication system (PECS) was designed to teach children with autism functional verbal behavior. Much research has demonstrated the effectiveness and efficiency of PECS in building verbal behavior. However, because PECS training is typically presented in a group format and later…

  15. Molecules to Materials for PEC Water Splitting

    SciTech Connect

    Neale, N. R.; Ruddy, D. A.; Lee, K.; Seabold, J. A.; Deutsch, T. G.; Dukovic, G.

    2013-01-01

    Advances in heterogeneous catalysis are driven by the formation of structure-property relationships at solid-liquid and solid-gaseous interfaces. The establishment of these relationships relies on cooperative research efforts on several fronts: prediction and analysis using high-level theoretical models, the development of new synthetic methods to prepare specific solid-state compositions and structures, new analytical methods to identify the active site and define interfacial properties, and mechanistic analysis of functioning catalysts. However, customized materials that allow for fine control of the interfacial properties at solid-liquid boundaries represent difficult synthetic targets. We have been investigating molecular synthons as precursors to advanced materials to address this challenge. In this presentation, we will discuss (1) the chemistry of molecular inorganic complexes, (2) their conversion to mixed-metal oxides, and (3) structure-property relationships of the resulting oxides relevant to PEC water splitting.

  16. The Unusual Suspects: Myths and Misconceptions Associated with PECS

    ERIC Educational Resources Information Center

    Bondy, Andy

    2012-01-01

    The Picture Exchange Communication System (PECS) is an alternative/augmentative communication protocol designed to help children and adults with autism and related disabilities to engage in functional communication. The protocol was developed over a number of years and was based on Skinner's analysis of verbal behavior. Publications about the…

  17. NEW SLUDGE DISINFECTION TECHNOLOGIES IN THE LITERATURE AND PEC APPLICATIONS

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC), has been reviewing novel sludge disinfection technologies and their abilities to protect human health and the environment. In the past several years many new disinfection technologies have surfaced not only in...

  18. NEW SLUDGE DISINFECTION TECHNOLOGIES IN THE LITERATURE AND PEC APPLICATIONS

    EPA Science Inventory

    Since it's creation in 1985, the Pathogen Equivalency Committee (PEC), has been reviewing novel sludge disinfection technologies and their abilities to protect human health and the environment. In the past several years many new disinfection technologies have surfaced not only in...

  19. The Unusual Suspects: Myths and Misconceptions Associated with PECS

    ERIC Educational Resources Information Center

    Bondy, Andy

    2012-01-01

    The Picture Exchange Communication System (PECS) is an alternative/augmentative communication protocol designed to help children and adults with autism and related disabilities to engage in functional communication. The protocol was developed over a number of years and was based on Skinner's analysis of verbal behavior. Publications about the…

  20. Social-Communicative Effects of the Picture Exchange Communication System (PECS) in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Russo, Luigi; Massagli, Angelo

    2012-01-01

    Background: The Picture Exchange Communication System (PECS) is a common treatment choice for non-verbal children with autism. However, little empirical evidence is available on the usefulness of PECS in treating social-communication impairments in autism. Aims: To test the effects of PECS on social-communicative skills in children with autism,…

  1. Social-Communicative Effects of the Picture Exchange Communication System (PECS) in Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Russo, Luigi; Massagli, Angelo

    2012-01-01

    Background: The Picture Exchange Communication System (PECS) is a common treatment choice for non-verbal children with autism. However, little empirical evidence is available on the usefulness of PECS in treating social-communication impairments in autism. Aims: To test the effects of PECS on social-communicative skills in children with autism,…

  2. PEC films prepared from Chitosan-Alginate coacervates.

    PubMed

    Yan, X; Khor, E; Lim, L Y

    2000-07-01

    Chitosan-alginate polyelectrolyte complex (PEC) have been prepared in situ in beads and microspheres. This study examines the preparation of suitable chitosan-alginate coacervates for casting into homogeneous PEC films for potential applications in packaging, controlled release systems and wound dressings. Coacervation between chitosan and alginate was rapid, but the rate may be controlled with the addition of water miscible organic solvents. Compared with ethanol and PEG200, acetone was the more promising solvent moderator. Suspensions of fine, uniformly dispersed coacervates were produced by a dropwise addition of 0.25% w/v chitosan solution (solvent: 1: 1 v/v of 2% acetic acid and acetone) into 0.25% w/v sodium alginate solution in water under rapid agitation. The PEC films were transparent and flexible. They exhibited high permeability to water vapor, but resisted complete dissolution in 0.1 M HCI, distilled water and pH 7.4 phosphate buffer solution. Microscopic heterogeneity in the films could be reduced by immersion in aqueous media, but this was accompanied by modifications in the thickness, permeability and mechanical property of the films.

  3. Comparative Pathogenesis of Tissue Culture-Adapted and Wild-Type Cowden Porcine Enteric Calicivirus (PEC) in Gnotobiotic Pigs and Induction of Diarrhea by Intravenous Inoculation of Wild-Type PEC

    PubMed Central

    Guo, M.; Hayes, J.; Cho, K. O.; Parwani, A. V.; Lucas, L. M.; Saif, L. J.

    2001-01-01

    Porcine enteric calicivirus (PEC/Cowden) causes diarrhea in pigs, grows in cell culture, and is morphologically and genetically similar to the Sapporo-like human caliciviruses. Genetic analysis revealed that the tissue culture-adapted (TC) Cowden PEC has one distant and three clustered amino acid substitutions in the capsid region and 2 amino acid changes in the RNA polymerase region compared to wild-type (WT) PEC (M. Guo, K.-O. Chang, M. E. Hardy, Q. Zhang, A. V. Parwani, and L. J. Saif, J. Virol. 73:9625–9631, 1999). In this study, the TC PEC, passaged in a porcine kidney cell line, and the WT PEC, passaged in gnotobiotic (Gn) pigs, were used to orally inoculate 13 4- to 6-day-old Gn pigs. No diarrhea developed in the TC-PEC-exposed pigs, whereas moderate diarrhea developed in the WT-PEC orally inoculated pigs, persisting for 2 to 5 days. Fecal virus shedding persisting for at least 7 days was detected by both reverse transcription (RT)-PCR and antigen-enzyme-linked immunosorbent assay (antigen-ELISA) in both TC-PEC and WT-PEC orally inoculated pigs but not in mock-inoculated pigs. The PEC particles were detected by immunoelectron microscopy (IEM) in intestinal contents from all the WT-PEC-inoculated pigs, but not from the TC-PEC-inoculated pigs. Mild (duodenum and jejunum) or no (ileum) villous atrophy was observed in histologic sections of the small intestines of TC-PEC-inoculated pigs, whereas WT PEC caused mild to severe (duodenum and jejunum) villous atrophy and fusion. Scanning electron microscopy confirmed mild shortening and blunting of villi in the duodenum and jejunum of the TC-PEC-inoculated pigs, in contrast to moderate to severe villous shortening and blunting in the duodenum and jejunum of WT-PEC-inoculated pigs. Higher numbers of PEC antigen-positive villous enterocytes were detected by immunofluorescent (IF) staining in the proximal small intestine of the WT-PEC-inoculated pigs, in contrast to low numbers of PEC antigen-positive enterocytes in

  4. Metal oxide semiconductors in PEC splitting of water

    NASA Astrophysics Data System (ADS)

    Satsangi, Vibha R.

    2007-09-01

    With hydrogen being accepted as fuel for the future, the world is looking forward to development of clean and sustainable methods of its production from renewable energy. In this context, area of research in the PEC splitting of water assumes great significance and the challenge is to develop corrosion resistant, chemically stable semiconductor that absorbs sunlight in the visible region and also has the band edges matching to the redox level of water. The advent of nanotechnology has opened new vistas in the production of semiconductor with large surface area for solar energy absorption and other favourable properties, which has lead to restudy the old workhorses, viz α-Fe IIO 3 and TiO II in the PEC splitting of water. This communication reports the study on metal oxides, towards the photoelectrochemical splitting of water as function of material properties and characteristics of semiconductor- electrolyte junction, viz; particle size, suitable dopants, crystalline phase, surface morphology, resistivity, bandgap, donor density and flatband potential. Effect of sensitizers and surface modification has also been investigated. Both the techniques of surface modification: (i) depositing metal dots and (ii) swift heavy ion irradiation in α-Fe IIO 3 were observed to be much effective in improving the photoresponse of the material. α-Fe IIO 3 thin films prepared using spray pyrolysis having Zn dots (dot height: 260 Å) on its surface exhibited the best of photocurrent density (1.82 mA/cm2), at 0.6 V applied bias. Nitrogen doped nanostructured TiO II prepared by sol gel method exhibited much better photoresponse as compared to any other dopant.

  5. Experimental Evaluation of the Training Structure of the Picture Exchange Communication System (PECS)

    ERIC Educational Resources Information Center

    Cummings, Anne R.; Carr, James E.; LeBlanc, Linda A.

    2012-01-01

    The Picture Exchange Communication System (PECS) is a picture-based alternative communication method that is widely accepted and utilized with individuals with disabilities. Although prior studies have examined the clinical efficacy of PECS, none have experimentally evaluated its manualized training structure. We experimentally evaluated the…

  6. Evaluation of pharmaceuticals in surface water: reliability of PECs compared to MECs.

    PubMed

    Celle-Jeanton, Hélène; Schemberg, Dimitri; Mohammed, Nabaz; Huneau, Frédéric; Bertrand, Guillaume; Lavastre, Véronique; Le Coustumer, Philippe

    2014-12-01

    Due to the current analytical processes that are not able to measure all the pharmaceutical molecules and to the high costs and the consumption of time to sample and analyze PhACs, models to calculate Predicted Environmental Concentrations (PECs) have been developed. However a comparison between MECs and PECs, taking into account the methods of calculations and peculiarly the parameters included in the calculation (consumption data, pharmacokinetic parameters, elimination rate in STPs and in the environment), is necessary to assess the validity of PECs. MEC variations of sixteen target PhACs [acetaminophen (ACE), amlodipine (AML), atenolol (ATE), caffeine (CAF), carbamazepine (CAR), doxycycline (DOX), epoxycarbamazepine (EPO), fluvoxamine (FLU), furosemide (FUR), hydrochlorothiazide (HYD), ifosfamide (IFO), losartan (LOS), pravastatin (PRA), progesterone (PROG), ramipril (RAM), trimetazidine (TRI)] have been evaluated during one hydrological cycle, from October 2011 to October 2012 and compared to PECs calculated by using an adaptation of the models proposed by Heberer and Feldmann (2005) and EMEA (2006). Comparison of PECs and MECS has been achieved for six molecules: ATE, CAR, DOX, FUR, HYD and PRA. DOX, FUR and HYD present differences between PECs and MECs on an annual basis but their temporal evolutions follow the same trends. PEC evaluation for these PhACs could then be possible but need some adjustments of consumption patterns, pharmacokinetic parameters and/or mechanisms of (bio)degradation. ATE, CAR and PRA are well modeled; PECs can then be used as reliable estimation of concentrations without any reserve. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. The PEC Network 1993. Directory of the Peace Education Commission. Peace Education Miniprints, No. 47.

    ERIC Educational Resources Information Center

    Bjerstedt, Ake, Ed.

    This extensive list of the council members of the Peace Education Commission (PEC) from 1992-1994 gives mailing addresses and some telephone and fax numbers to enable direct contact with network members. The Peace Education Commission (PEC) facilitates international cooperation among individuals interested in peace education and research related…

  8. Predicting progress in Picture Exchange Communication System (PECS) use by children with autism.

    PubMed

    Pasco, Greg; Tohill, Christina

    2011-01-01

    The Picture Exchange Communication System (PECS) is a widely used communication intervention for non-verbal children with autism spectrum disorder. Findings for the benefits of PECS have almost universally been positive, although there is very limited information about the characteristics of PECS users that determine the amount of progress that they are likely to make. To explore the utility of using children's developmental age to predict the subsequent degree of progress using PECS. In a retrospective study, 23 non-verbal 5- and 6-year-old children with autism spectrum disorder attending a special school were assessed to determine their highest level of PECS ability. They were then allocated to one of two groups depending on whether or not they had mastered PECS phase III. All participants had been assessed using the Psycho-Educational Profile-Revised (PEP-R) on entry to the school and before being introduced to PECS. Total developmental age scores were examined to determine whether they accurately predicted membership of the two PECS ability groups. All the 16 children who had mastered PECS phase III had total developmental age scores of 16 months or above, whilst six of the seven children who had not progressed beyond phase III scored below 16 months--the other child had a score of 16 months. The assessment of the developmental level of potential PECS users may provide valuable predictive information for speech-and-language therapists and other professionals in relation to the likely degree of progress and in setting realistic and achievable targets. © 2010 Royal College of Speech & Language Therapists.

  9. Biliprotein chromophore attachment: chaperone-like function of the PecE subunit of alpha-phycoerythrocyanin lyase.

    PubMed

    Böhm, Stephan; Endres, Stefanie; Scheer, Hugo; Zhao, Kai-Hong

    2007-08-31

    Biliproteins are post-translationally modified by chromophore addition. In phycoerythrocyanin, the heterodimeric lyase PecE/F covalently attaches phycocyanobilin (PCB) to cysteine-alpha84 of the apoprotein PecA, with concomitant isomerization to phycoviolobilin. We found that: (a) PecA adds autocatalytically PCB, yielding a low absorbance, low fluorescence PCB.PecA adduct, termed P645 according to its absorption maximum; (b) In the presence of PecE, a high absorbance, high fluorescence PCB.PecA adduct is formed, termed P641; (c) PecE is capable of transforming P645 to P641; (d) When in stop-flow experiments, PecA and PecE were preincubated before chromophore addition, a red-shifted intermediate (P650, tau=32 ms) was observed followed by a second, which was blue-shifted (P605, tau=0.5 s), and finally a third (P638, tau=14 s) that yielded the adduct (P641, tau=20 min); (e) The reaction was slower, and P605 was missing, if PecA and PecE were not preincubated; (f) Gel filtration gave no evidence of a stable complex between PecA and PecE; however, complex formation is induced by adding PCB; and (g) A red-shifted intermediate was also formed, but more slowly, with phycoerythrobilin, and denaturation showed that this is not yet covalently bound. We conclude, therefore, that PecA and PecE form a weak complex that is stabilized by PCB, that the first reaction step involves a conformational change and/or protonation of PCB, and that PecE has a chaperone-like function on the chromoprotein.

  10. Extra-intestinal pathogenic Escherichia coli (ExPEC): Disease, carriage and clones.

    PubMed

    Dale, Adam P; Woodford, Neil

    2015-12-01

    Extra-intestinal pathogenic Escherichia coli (ExPEC) have a complex phylogeny, broad virulence factor (VF) armament and significant genomic plasticity, and are associated with a spectrum of host infective syndromes ranging from simple urinary tract infection to life-threatening bacteraemia. Their importance as pathogens has come to the fore in recent years, particularly in the context of the global emergence of hyper-virulent and antibiotic resistant strains. Despite this, the mechanisms underlying ExPEC transmission dynamics and clonal selection remain poorly understood. Large-scale epidemiological and clinical studies are urgently required to ascertain the mechanisms underlying these processes to enable the development of novel evidence-based preventative and therapeutic strategies. In the current review, we provide a concise summary of the methods utilised for ExPEC phylogenetic delineation before exploring in detail the associations between ExPEC VFs and site-specific disease. We then consider the role of ExPEC as an intestinal colonist and outline known associations between ExPEC clonal variation, specific disease syndromes and antibiotic resistance.

  11. Social-communicative effects of the Picture Exchange Communication System (PECS) in autism spectrum disorders.

    PubMed

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Russo, Luigi; Massagli, Angelo

    2012-01-01

    The Picture Exchange Communication System (PECS) is a common treatment choice for non-verbal children with autism. However, little empirical evidence is available on the usefulness of PECS in treating social-communication impairments in autism. To test the effects of PECS on social-communicative skills in children with autism, concurrently taking into account standardized psychometric data, standardized functional assessment of adaptive behaviour, and information on social-communicative variables coded in an unstructured setting. Eighteen preschool children (mean age = 38.78 months) were assigned to two intervention approaches, i.e. PECS and Conventional Language Therapy (CLT). Both PECS (Phases I-IV) and CLT were delivered three times per week, in 30-min sessions, for 6 months. Outcome measures were the following: Autism Diagnostic Observation Schedule (ADOS) domain scores for Communication and Reciprocal Social Interaction; Language and Personal-Social subscales of the Griffiths' Mental Developmental Scales (GMDS); Communication and Social Abilities domains of the Vineland Adaptive Behavior Scales (VABS); and several social-communicative variables coded in an unstructured setting. Results demonstrated that the two groups did not differ at Time 1 (pre-treatment assessment), whereas at Time 2 (post-test) the PECS group showed a significant improvement with respect to the CLT group on the VABS social domain score and on almost all the social-communicative abilities coded in the unstructured setting (i.e. joint attention, request, initiation, cooperative play, but not eye contact). These findings showed that PECS intervention (Phases I-IV) can improve social-communicative skills in children with autism. This improvement is especially evident in standardized measures of adaptive behaviour and measures derived from the observation of children in an unstructured setting. © 2012 Royal College of Speech and Language Therapists.

  12. Optic flow neurons in area PEc integrate eye and head position signals.

    PubMed

    Raffi, Milena; Persiani, Michela; Piras, Alessandro; Squatrito, Salvatore

    2014-05-07

    Neurons in area PEc, a visual area located in the superior parietal lobule, are activated by optic flow stimuli. An important issue is whether PEc neurons are able to integrate multimodal signals, such as those related to optic flow selectivity with those about eye and head position. The aim of this study was to assess if angle of gaze and/or head rotation modify the spatial representation of the focus of expansion (FOE), varying FOE, fixation point and head position in space. We found that the rotation of head modulated the firing activity of PEc optic flow neurons. The head position also changed the angle of gaze effect on the PEc neuronal activity. All recorded neurons showed a main interaction effect between head and eye position upon the selectivity for optic flow stimuli. These results seem to suggest that PEc optic flow neurons use different reference frames depending on the position of the eye and/or the head in space emphasizing a possible contribution of this area in guiding locomotion by integrating multiple extraretinal inputs.

  13. Chasing the long tail of environmental data: PEcAn is nuts about Brown Dog

    NASA Astrophysics Data System (ADS)

    Dietze, M.; Cowdery, E.; Desai, A. R.; Gardella, A.; Kelly, R.; Kooper, R.; LeBauer, D.; Mantooth, J.; McHenry, K.; Serbin, S.; Shiklomanov, A. N.; Simkins, J.; Viskari, T.; Raiho, A.

    2015-12-01

    The Predictive Ecosystem Analyzer (PEcAn) is a ecological modeling informatics system that manages the flows of information in and out of terrestrial biosphere models, provenance tracking, visualization, analysis, and model-data fusion. We are in the process of scaling the PEcAn system from one that currently supports a handful of models and system nodes to one that aims to provide bottom-up connectivity across much of the model-data integration done by the terrestrial biogeochemistry community. This talk reports on the current state of PEcAn, it's data processing workflows, and the near- and long-term challenges faced. Particular emphasis will be given to the tools being developed by the Brown Dog project to make unstructured, un-curated data more accessible: the Data Access Proxy (DAP) and the Data Tilling Service (DTS). The use of the DAP to process meteorological data and the DTS to read vegetation data will be demonstrated and other Brown Dog environmental case studies will be briefly touched on. Beyond data processing, facilitating data discovery and import into PEcAn and distributing analyses across the PEcAn network (i.e. bringing models to data) are key challenges moving forward.

  14. Rare case of uterine PEC-oma (perivascular epithelioid cell tumor) recurrence. Case report and literature review.

    PubMed

    Issat, Tadeusz; Maciejewski, Tomasz; Beta, Jarosław; Jakimiuk, J Artur

    2012-07-01

    Perivascular epithelioid cell tumor (PEC-oma) is a rare mesenchymal neoplasm. Literature reports more than 100 cases of PEC-oma, a third of which is of uterine or uterine retroperitoneum origin. The case of a 59-year-old woman presented here is, to the best of our knowledge, the first described fast uterine PEC-oma recurrence of the tumor of the gastrointestinal tract origin. In this text the authors also present literature review concerning this rare female tumor

  15. Template-free synthesis of hematite photoanodes with nanostructured ATO conductive underlayer for PEC water splitting.

    PubMed

    Wang, Degao; Zhang, Yuying; Wang, Jianqiang; Peng, Cheng; Huang, Qing; Su, Shao; Wang, Lianhui; Huang, Wei; Fan, Chunhai

    2014-01-08

    Hematite is a promising semiconductor candidate for PEC water splitting. However, hematite is far well short of the theoretical value of solar-to-fuel conversion efficiency because of the fast recombination of photogenerated carriers. To address this limitation, a facile template-free preparation of hematite photoanode with nanostructured ATO (antimony-doped tin oxide) conductive underlayer served as a scaffold to transport photogenerated electron was developed to decrease the recombination opportunities of the carriers. Furthermore, the constructed ATO scaffold could also increase the light absorption of hematite and the number of the carriers, resulting in better PEC performance of hematite.

  16. Comparison of PECS and the Use of a VOCA: A Replication

    ERIC Educational Resources Information Center

    Beck, Ann R.; Stoner, Julia B.; Bock, Stacey J.; Parton, Tom

    2008-01-01

    This study compares use of the Picture Exchange Communication System (PECS) and a Voice Output Communication Aide (VOCA) with four preschool children who were either non-speaking or limited in their ability to speak and did not use an AAC system to communicate functionally. An alternating treatment single subject design was used to measure…

  17. Effects of PECS Phase III Application Training on Independent Mands in Young Children with Autism

    ERIC Educational Resources Information Center

    Love, Jessica June

    2013-01-01

    The purpose of this study was to examine the effects of PECS phase III application training on independent mands in young children with autism. Participants were five children with autism ranging from ages 2 to 4 years old. A multiple baseline across participants was used to evaluate acquisition of independent correct mands across baseline and…

  18. The Application of PECS in a Deaf Child with Autism: A Case Study

    ERIC Educational Resources Information Center

    Malandraki, Georgia A.; Okalidou, Areti

    2007-01-01

    A 10-year-old nonverbal Greek boy, C.Z., who had been diagnosed with both bilateral sensorineural profound hearing loss and autism, was taught to use the Picture Exchange Communication System (PECS), with some modifications and extensions, over a 4-month intensive intervention period. C.Z.'s original communication and behavioral status as well as…

  19. The PEcAn Project: Model-Data Ecoinformatics for the Observatory Era

    NASA Astrophysics Data System (ADS)

    Dietze, M. C.; LeBauer, D. S.; Davidson, C. D.; Desai, A. R.; Kooper, R.; McHenry, K.; Mulrooney, P.

    2011-12-01

    The fundamental questions about how terrestrial ecosystems will respond to climate change are straightforward and well known, yet a small number of important gaps separate the information we have gathered from the understanding required to inform policy and management. A critical gap is that no one data source provides a complete picture of the terrestrial biosphere, and therefore multiple data sources must be integrated in a sensible manner. Process-based models represent an ideal framework for this synthesis, but to date model-data synthesize has only made use of a subset of the available data types, and remains inaccessible to much of the scientific community, largely due to the daunting ecoinformatics challenges. The Predictive Ecosystem Analyzer (PEcAn) is an open-source scientific workflow system and ecoinformatics toolbox that manages the flow of information in and out of regional-scale terrestrial biosphere models, facilitates formal data assimilation, and enables more effective feedbacks between models and field research. PEcAn makes complex analyses transparent, repeatable, and accessible to a diverse array of researchers. PEcAn is not model specific, but rather encapsulates any ecosystem model within a set of standardized input and output modules. Herein we demonstrate PEcAn's ability to automate many of the tasks involved in modeling by gathering and processing a diverse arrays of data sets, initiating ensembles of model runs, visualizing output, and comparing models to observations. PEcAn employs a fully Bayesian approach to model parameterization and the estimation of ecosystem pools and fluxes that allows a straightforward propagation of uncertainties into analyses and forecasts. This approach also makes possible the synthesis of a diverse array of data types operating at different spatial and temporal scales and to easily update predictions as new information becomes available. We also demonstrate PEcAn's ability to iteratively synthesize

  20. The effects of PECS teaching to Phase III on the communicative interactions between children with autism and their teachers.

    PubMed

    Carr, Deborah; Felce, Janet

    2007-04-01

    The study investigated the impact of mastery of the Picture Exchange Communication System (PECS) to Phase III, on the communications of children with autism. Children aged between 3 and 7 years, formed a PECS intervention group and a non-intervention control group. The intervention group received 15 h of PECS teaching over 5 weeks. Three 2-h classroom observations recorded communications between the children and their teachers. These occurred: 6 weeks before teaching; during the week immediately prior to teaching; during the week immediately following teaching. For the control group, two 2-h observations were separated by a 5-week interval without PECS teaching. Communicative initiations and dyadic interactions increased significantly between the children and teachers in the PECS group but not for the control group.

  1. Claustral afferents of superior parietal areas PEc and PE in the macaque.

    PubMed

    Gamberini, Michela; Passarelli, Lauretta; Bakola, Sophia; Impieri, Daniele; Fattori, Patrizia; Rosa, Marcello G P; Galletti, Claudio

    2017-04-15

    The exposed surface of the primate superior parietal cortex includes two cytoarchitectonically defined areas, the PEc and PE. In the present study we describe the distribution of neurons projecting from the claustrum to these areas. Retrograde neuronal tracers were injected by direct visualization of regions of interest, and the location of injection sites was reconstructed relative to cytoarchitectural borders. For comparison, the patterns of claustral label that resulted from injections involving neighboring cytoarchitectonic areas were analyzed. We found that the claustral territories sending projections to areas PE and PEc partially overlapped zones previously shown to form projections to the posterior parietal, somatosensory, visual, and motor cortex. The projection zones to the PE and PEc overlapped extensively, and consisted of multiple patches separated by label-free zones. Most of the labeled neurons were located in the posterior-ventral part of the claustrum. Area PE received additional inputs from a posterior-dorsal part of the claustrum, which has been previously reported to project to the somatosensory cortex, while the PEc receives additional input from an anterior-ventral region of the claustrum, which has been reported to project to the visual association cortex. These observations reflect the known functional properties of the PE and PEc, with the former containing neurons that are predominantly involved in somatosensory processing, and the latter including both somatosensory and visual neurons. The present results suggest that the claustrum projections may help coordinate the activity of an extensive neural circuit involved in sensory and motor processing for movement execution. J. Comp. Neurol. 525:1475-1488, 2017. © 2016 Wiley Periodicals, Inc.

  2. The ABCG transporter PEC1/ABCG32 is required for the formation of the developing leaf cuticle in Arabidopsis.

    PubMed

    Fabre, Guillaume; Garroum, Imène; Mazurek, Sylwester; Daraspe, Jean; Mucciolo, Antonio; Sankar, Martial; Humbel, Bruno M; Nawrath, Christiane

    2016-01-01

    The cuticle is an essential diffusion barrier on aerial surfaces of land plants whose structural component is the polyester cutin. The PERMEABLE CUTICLE1/ABCG32 (PEC1) transporter is involved in plant cuticle formation in Arabidopsis. The gpat6 pec1 and gpat4 gapt8 pec1 double and triple mutants are characterized. Their PEC1-specific contributions to aliphatic cutin composition and cuticle formation during plant development are revealed by gas chromatography/mass spectrometry and Fourier-transform infrared spectroscopy. The composition of cutin changes during rosette leaf expansion in Arabidopsis. C16:0 monomers are in higher abundance in expanding than in fully expanded leaves. The atypical cutin monomer C18:2 dicarboxylic acid is more prominent in fully expanded leaves. Findings point to differences in the regulation of several pathways of cutin precursor synthesis. PEC1 plays an essential role during expansion of the rosette leaf cuticle. The reduction of C16 monomers in the pec1 mutant during leaf expansion is unlikely to cause permeability of the leaf cuticle because the gpat6 mutant with even fewer C16:0 monomers forms a functional rosette leaf cuticle at all stages of development. PEC1/ABCG32 transport activity affects cutin composition and cuticle structure in a specific and non-redundant fashion.

  3. Impacts of a PECS instructional coaching intervention on practitioners and children with autism.

    PubMed

    Ganz, Jennifer B; Goodwyn, Fara D; Boles, Margot M; Hong, Ee Rea; Rispoli, Mandy J; Lund, Emily M; Kite, Elizabeth

    2013-09-01

    There is a growing research literature on the potential benefits of augmentative and alternative communication (AAC) for individuals with autism; however few studies have investigated implementation of AAC within real-life contexts. Thus, the purpose of this study was to investigate the impact of training for practitioners in implementation of aided AAC, and to examine implementation of Picture Exchange Communication System (PECS) in real-life contexts. In particular, this study involved the implementation of instructional coaching to increase opportunities offered by behavioral therapists for their preschool-aged clients to use PECS to make requests. Results indicated increases in therapist implementation of AAC and client use of AAC in trained contexts, with limited generalization to untrained contexts.

  4. Discharge of pharmaceutical products (PPs) through a conventional biological sewage treatment plant: MECs vs PECs?

    PubMed

    Coetsier, C M; Spinelli, S; Lin, L; Roig, B; Touraud, E

    2009-07-01

    Pharmaceuticals for human use are consumed in significant quantities and their occurrence in aquatic systems has been reported by a number of authors. In the context of environmental risk assessment, there is an increasing interest in evaluating the discharge of pharmaceutical products to surface waters through sewage treatment plants (STP). This case study was carried out on a conventional biological treatment plant (Alès, France) and focused on a set of eleven drugs representing the main therapeutic classes. Measured environmental concentrations (MECs) range from the low ng L(-1) to 1.5 microg L(-1) in effluent and up to few hundred ng L(-1) in receiving surface waters. There is a good agreement between MEC and predicted environmental concentration (PEC) values for seven of the eleven investigated drugs in STP effluent. There is not such a good match between PEC and MEC values in surface waters, and this highlights the limits of this approach, at the local scale.

  5. The PEcAn Project: Accessible Tools for On-demand Ecosystem Modeling

    NASA Astrophysics Data System (ADS)

    Cowdery, E.; Kooper, R.; LeBauer, D.; Desai, A. R.; Mantooth, J.; Dietze, M.

    2014-12-01

    Ecosystem models play a critical role in understanding the terrestrial biosphere and forecasting changes in the carbon cycle, however current forecasts have considerable uncertainty. The amount of data being collected and produced is increasing on daily basis as we enter the "big data" era, but only a fraction of this data is being used to constrain models. Until we can improve the problems of model accessibility and model-data communication, none of these resources can be used to their full potential. The Predictive Ecosystem Analyzer (PEcAn) is an ecoinformatics toolbox and a set of workflows that wrap around an ecosystem model and manage the flow of information in and out of regional-scale TBMs. Here we present new modules developed in PEcAn to manage the processing of meteorological data, one of the primary driver dependencies for ecosystem models. The module downloads, reads, extracts, and converts meteorological observations to Unidata Climate Forecast (CF) NetCDF community standard, a convention used for most climate forecast and weather models. The module also automates the conversion from NetCDF to model specific formats, including basic merging, gap-filling, and downscaling procedures. PEcAn currently supports tower-based micrometeorological observations at Ameriflux and FluxNET sites, site-level CSV-formatted data, and regional and global reanalysis products such as the North American Regional Reanalysis and CRU-NCEP. The workflow is easily extensible to additional products and processing algorithms.These meteorological workflows have been coupled with the PEcAn web interface and now allow anyone to run multiple ecosystem models for any location on the Earth by simply clicking on an intuitive Google-map based interface. This will allow users to more readily compare models to observations at those sites, leading to better calibration and validation. Current work is extending these workflows to also process field, remotely-sensed, and historical

  6. UPDATE ON PEC ACTIVITIES INCLUDING NEW EVALUATION CRITERIA, THE APPLICATION COMPLETENESS CHECKLIST, AND STATUS OF THE WEBSITE DEVELOPMENT

    EPA Science Inventory

    US EPA's Pathogen Equivalency Committee (PEC) has updated the evaluation criteria it uses to make recommendations of equivalency (to processes acceptable under 40CFR503) on innovative or alternative sludge pathogen reduction processes. These criteria will be presented along with ...

  7. UPDATE ON PEC ACTIVITIES INCLUDING NEW EVALUATION CRITERIA, THE APPLICATION COMPLETENESS CHECKLIST, AND STATUS OF THE WEBSITE DEVELOPMENT

    EPA Science Inventory

    US EPA's Pathogen Equivalency Committee (PEC) has updated the evaluation criteria it uses to make recommendations of equivalency (to processes acceptable under 40CFR503) on innovative or alternative sludge pathogen reduction processes. These criteria will be presented along with ...

  8. Mechanical and Thermal Properties of Pulsed Electric Current Sintered (PECS) Cu-Diamond Compacts

    NASA Astrophysics Data System (ADS)

    Ritasalo, Riina; Kanerva, Ulla; Ge, Yanling; Hannula, Simo-Pekka

    2014-04-01

    In this work, dispersion strengthening of copper by diamonds is explored. In particular, the influence of 50- and 250-nm diamonds at contents of 3 and 6 vol. pct on the mechanical and thermal properties of pulsed electric current sintered (PECS) Cu composites is studied. The composite powders were prepared by mechanical alloying in argon atmosphere using a high-energy vibratory ball mill. The PECS compacts prepared had high density (>97 pct of T.D.) with quite evenly distributed diamonds. The effectiveness of dispersoids in increasing the microhardness was more pronounced at a smaller particle size and larger volume fraction, explained by Hall-Petch and Orowan strengthening models. The microhardness of Cu with 6 and 3 vol. pct nanodiamonds and pure sm-Cu (submicron-sized Cu) was 1.77, 1.46, and 1.02 GPa, respectively. In annealing experiments at 623 K to 873 K (350 °C to 600 °C), the composites with 6 vol. pct dispersoids retained their hardness better than those with less dispersoids or sm-Cu. The coefficient of thermal expansion was lowered when diamonds were added, being the lowest at about 14 × 10-6 K-1 between 473 K and 573 K (200 °C and 300 °C). Good bonding between the copper and diamond was qualitatively demonstrated by nanoindentation. In conclusion, high-quality Cu-diamond composites can be produced by PECS with improved strength and better thermal stability than for sm-Cu.

  9. Probability Density Function for Waves Propagating in a Straight PEC Rough Wall Tunnel

    SciTech Connect

    Pao, H

    2004-11-08

    The probability density function for wave propagating in a straight perfect electrical conductor (PEC) rough wall tunnel is deduced from the mathematical models of the random electromagnetic fields. The field propagating in caves or tunnels is a complex-valued Gaussian random processing by the Central Limit Theorem. The probability density function for single modal field amplitude in such structure is Ricean. Since both expected value and standard deviation of this field depend only on radial position, the probability density function, which gives what is the power distribution, is a radially dependent function. The radio channel places fundamental limitations on the performance of wireless communication systems in tunnels and caves. The transmission path between the transmitter and receiver can vary from a simple direct line of sight to one that is severely obstructed by rough walls and corners. Unlike wired channels that are stationary and predictable, radio channels can be extremely random and difficult to analyze. In fact, modeling the radio channel has historically been one of the more challenging parts of any radio system design; this is often done using statistical methods. In this contribution, we present the most important statistic property, the field probability density function, of wave propagating in a straight PEC rough wall tunnel. This work only studies the simplest case--PEC boundary which is not the real world but the methods and conclusions developed herein are applicable to real world problems which the boundary is dielectric. The mechanisms behind electromagnetic wave propagation in caves or tunnels are diverse, but can generally be attributed to reflection, diffraction, and scattering. Because of the multiple reflections from rough walls, the electromagnetic waves travel along different paths of varying lengths. The interactions between these waves cause multipath fading at any location, and the strengths of the waves decrease as the distance

  10. The effects of parent-implemented PECS training on improvisation of mands by children with autism.

    PubMed

    Ben Chaabane, Delia B; Alber-Morgan, Sheila R; DeBar, Ruth M

    2009-01-01

    The present study examined the extent to which mothers were able to train their children, 2 boys with autism, to exchange novel pictures to request items using the picture exchange communication system (PECS). Generalization probes assessing each child's ability to mand for untrained items were conducted throughout conditions. Using a multiple baseline design, results demonstrated that both children improvised by using alternative symbols when the corresponding symbol was unavailable across all symbol categories (colors, shapes, and functions) and that parents can teach their children to use novel pictorial response forms.

  11. Passive emission colorimetric sensor (PECS) for measuring emission rates of formaldehyde based on an enzymatic reaction and reflectance photometry.

    PubMed

    Shinohara, Naohide; Kajiwara, Tomohisa; Ohnishi, Masato; Kodama, Kenichi; Yanagisawa, Yukio

    2008-06-15

    A coin-sized passive emission colorimetric sensor (PECS) based on an enzymatic reaction and a portable reflectance photometry device were developed to determine the emission rates of formaldehyde from building materials and other materials found indoors in only 30 minutes on-site. The color change of the PECS linearly correlated to the concentration of formaldehyde aqueous solutions up to 28 microg/mL. The correlation between the emission rates measured by using the PECS and those measured by using a desiccator method or by using a chamber method was fitted with a linear function and a power function, and the determination coefficients were more than 0.98. The reproducible results indicate that the emission rates could be obtained with the correlation equations from the data measured by using the PECS and the portable reflectance photometry device. Limits of detection (LODs) were 0.051 mg/L for the desiccator method and 3.1 microg/m2/h for the chamber method. Thus, it was confirmed that the emission rates of formaldehyde from the building materials classified as F four-star (< 0.3 mg/L (desiccator method) or < 5.0 microg/m2/h (chamber method)), based on Japanese Industrial Standards (JIS), could be measured with the PECS. The measurement with PECS was confirmed to be precise (RSD < 10%). Other chemicals emitted from indoor materials, such as methanol, ethanol, acetone, toluene, and xylene, interfered little with the measurement of formaldehyde emission rates by using the PECS.

  12. Prospect: A Picture Exchange Communication System (PECS)-based Instant Messaging Application for Autism Spectrum Condition

    NASA Astrophysics Data System (ADS)

    Raja, Pravind; Zainuri Saringat, Mohd; Mustapha, Aida; Zainal, Abidah

    2017-08-01

    Autism Spectrum Disorder (ASC) has widely gained the common attention from the public especially autistic communities. Individuals with ASC are said to have poor verbal skills and this affects them in carrying out their daily basis which they are afraid to expose themselves to the world due to their problems. ASC is diagnosed among children ranging from ages 5-12 years old and they suffer from the abnormal functioning of the brain which in turn causes lack of development activities. Thus, studies have shown that diagrammatic approaches help children with ASC to overcome their issues and improvise their visual and verbal skills. Picture Exchange Communication System or PECS consists of a series of illustrated cards and each cards has its own illustration with a caption on it. These children will understand the cards and they can compile several other cards to form sentences. This paper presents a mobile application called the Prospect, which has been developed using the agile development model for digital representation of PECS. The application is hoped to enhance the learning process and a better yielding results.

  13. TolC promotes ExPEC biofilm formation and curli production in response to medium osmolarity.

    PubMed

    Hou, Bo; Meng, Xian-Rong; Zhang, Li-Yuan; Tan, Chen; Jin, Hui; Zhou, Rui; Gao, Jian-Feng; Wu, Bin; Li, Zi-Li; Liu, Mei; Chen, Huan-Chun; Bi, Ding-Ren; Li, Shao-Wen

    2014-01-01

    While a high osmolarity medium activates Cpx signaling and causes CpxR to repress csgD expression, and efflux protein TolC protein plays an important role in biofilm formation in Escherichia coli, whether TolC also responds to an osmolarity change to regulate biofilm formation in extraintestinal pathogenic E. coli (ExPEC) remains unknown. In this study, we constructed ΔtolC mutant and complement ExPEC strains to investigate the role of TolC in the retention of biofilm formation and curli production capability under different osmotic conditions. The ΔtolC mutant showed significantly decreased biofilm formation and lost the ability to produce curli fimbriae compared to its parent ExPEC strain PPECC42 when cultured in M9 medium or 1/2 M9 medium of increased osmolarity with NaCl or sucrose at 28°C. However, biofilm formation and curli production levels were restored to wild-type levels in the ΔtolC mutant in 1/2 M9 medium. We propose for the first time that TolC protein is able to form biofilm even under high osmotic stress. Our findings reveal an interplay between the role of TolC in ExPEC biofilm formation and the osmolarity of the surrounding environment, thus providing guidance for the development of a treatment for ExPEC biofilm formation.

  14. Minute perivascular epithelioid cell (PEC) nests in the abdominal lymph nodes--a putative precursor of PEComa.

    PubMed

    Nagasaka, Toru; Murakami, Yoshiko; Sasaki, Eiichi; Hosoda, Waki; Nakanishi, Toru; Yatabe, Yasushi

    2015-04-01

    A perivascular epithelioid cell tumor (PEComa) is a peculiar growth defined as a mesenchymal tumor composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Because neither normal counterparts nor precursor lesions of PEComa have been identified, we examined minute PEC nests, ranged from 0.8 mm to 10 mm, to investigate the possible origin of the PEComa. We examined a total of 80 677 para-aortic and pelvic lymph nodes that were systematically dissected from 1656 patients for gynecological malignancies. The identified lesions were confirmed immunohistochemically with multiple PEC markers, including smooth muscle actin, HMB45, melan-A, MiTF, ER and PgR. A total of 66 minute PEC nests were found in 21 patients (1.3% of the total population) with an average frequency of 3.1 lesions per patient. In cases of multiple involvement, 11 of 13 nests were located at the same level of multiple lymph node or on continuous levels. The lesions were preferentially distributed at the level of para-aortic and high pelvic lymph nodes. All nests were positive for actin and HMB45, whereas the other markers were positive with varying frequencies. The minute PEC nests may be associated with the possible normal counterpart of PEComas. © 2015 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.

  15. A Comparison of PECS and iPad to Teach Requesting to Pre-schoolers with Autistic Spectrum Disorders.

    PubMed

    Agius, May M; Vance, Margaret

    2016-01-01

    Few studies have compared the efficacy of the Picture Exchange Communication System (PECS) and iPads used as speech generating devices (SGDs), and none have targeted preschoolers. This study compares the relative efficacy of PECS and an iPad/SGD with three preschool-aged children with autism spectrum disorder and limited functional speech who lived in Malta. The study utilized an adapted alternating treatment design embedded in a multiple baseline design, with requesting of reinforcers as the dependent variable. Visual analysis of the results indicated that all participants required more prompted trials and sessions for the iPad/SGD condition. All participants learned a three step navigational sequence on the iPad. Participant preference probes were inconclusive and were not linked to speed of acquisition of requesting skills. Results suggest that both PECS and an iPad could be appropriate for teaching requesting skills to beginning communicators.

  16. Spondylodiscitis in a healthy 12-year-old girl with Extraintestinal pathogenic Escherichia coli (ExPEC) bacteraemia.

    PubMed

    Gaschignard, J; Geslain, G; Mallet, C; Lorrot, M; Blot, N; Alison, M; Bonacorsi, S

    2017-05-31

    Escherichia coli (E. coli) is rarely implicated in bone or joint infections in children. We discuss the case of a healthy 12-year-old girl with an E. coli bacteraemia and a T11-T12 spondylodiscitis revealed by magnetic resonance imaging. The strain harboured serogroup O1:K1 and virulence factors common to highly virulent extra intestinal pathogenic E. coli (ExPEC). Immunological work-up was normal. The identification of E. coli in a spondylodiscitis should lead to the search for immunosuppression of the host and virulence factors of the strain, particularly those of ExPEC.

  17. Ultra-wideband noise radar imaging of cylindrical PEC objects using diffraction tomography

    NASA Astrophysics Data System (ADS)

    Shin, Hee Jung; Narayanan, Ram M.; Rangaswamy, Muralidhar

    2014-05-01

    In this paper, we show that a single transmission of a random noise waveform may not sufficient to obtain a successful tomographic image of an object. In order to overcome this shortcoming, multiple independent and identically distributed (iid) random noise waveforms over a frequency range from 8 to 10 GHz are transmitted to reconstruct the final image of various objects. Diffraction tomography theorem is applied for each noise waveform transmission so that the image of the multiple objects is reconstructed based on the backward scattered field at the end of each noise waveform transmission realization. After all iid noise waveforms are transmitted, the final tomographic image of the target is reconstructed by averaging all obtained images from multiple transmissions. Several numerical simulations in the spatial frequency domain are performed, and the successful tomographic image of the multiple cylindrical PEC objects is achieved after transmission of multiple iid ultra-wideband (UWB) random noise waveforms.

  18. Thermoelectric properties of hot-pressed and PECS-sintered magnesium-doped copper aluminum oxide

    SciTech Connect

    Liu, Chang; Morelli, Donald T

    2011-02-03

    Copper aluminum oxide (CuAlO{sub 2}) is considered as a potential candidate for thermoelectric applications. Partially magnesium-doped CuAlO{sub 2} bulk pellets were fabricated using solid-state reactions, hot-pressing, and pulsed electric current sintering (PECS) techniques. X-ray diffraction and scanning electron microscopy were adopted for structural analysis. High-temperature transport property measurements were performed on hot-pressed samples. Electrical conductivity increased with Mg doping before secondary phases became significant, while the Seebeck coefficient displayed the opposite trend. Thermal conductivity was consistently reduced as the Mg concentration increased. Effects of Mg doping, preparation conditions, and future modification on this material’s properties are discussed.

  19. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance

    NASA Astrophysics Data System (ADS)

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-01

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current-voltage (I-V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I-V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

  20. Oxygen modulation of flexible PbS/Pb Schottky junction PEC cells with improved photoelectric performance.

    PubMed

    Wang, Peng; Fan, Libo; Guo, Qiuquan; Shi, Hongcai; Wang, Liwen; Liu, Yujian; Li, Ming; Zhang, Chunli; Yang, Jun; Zheng, Zhi

    2016-09-02

    Flexible photoelectric devices are emerging as a new class of photovoltaic cells. In this study, lead (Pb) foil was used as a flexible substrate to grow in situ lead sulfide (PbS) film with good uniformity and adhesion by a solvothermal elemental direct reaction, resulting in a PbS/Pb Schottky junction formed naturally between the PbS film and underlying Pb foil. We found that the photocurrent response of the photoelectrochemical (PEC) cell was greatly improved through a facile oxygen (O2)-modulation-based post-processing technique. O2 could decompose the organic residue and oxidize the Pb at the interface between the PbS film and Pb foils. Different characterization techniques, including thermogravimetric analysis, differential scanning calorimetry, x-ray diffraction, energy-dispersive x-ray spectroscopy, x-ray photoelectron spectroscopy, the change in transient photocurrent density (J p) with time (t), dark current-voltage (I-V) and absorption spectra were applied to get a full understanding of the O2 modulation effect. The oxidization treatment of the PbS film could regulate the flow of charge carriers to reduce their recombination, leading to photoresponse enhancement for the PEC cells. In particular, the process could modulate the tunneling current and interface states to optimize dark I-V characteristics. In addition, the magnitude of the barrier height can be tuned by O2 modulation, which was explained by theoretical analysis and calculation. We also demonstrated that the in situ formed PbS film has outstanding adhesion on the flexible Pb substrate. Our film synthesis method and post O2-modulation design as well as the corresponding device assembly may provide a novel perspective to the flexible PCE-cell-related research.

  1. Meta-Analysis of PECS with Individuals with ASD: Investigation of Targeted versus Non-Targeted Outcomes, Participant Characteristics, and Implementation Phase

    ERIC Educational Resources Information Center

    Ganz, Jennifer B.; Davis, John L.; Lund, Emily M.; Goodwyn, Fara D.; Simpson, Richard L.

    2012-01-01

    The Picture Exchange Communication System (PECS) is a widely used picture/icon aided augmentative communication system designed for learners with autism and other developmental disorders. This meta-analysis analyzes the extant empirical literature for PECS relative to targeted (functional communication) and non-targeted concomitant outcomes…

  2. Long-Term Effects of PECS on Social-Communicative Skills of Children with Autism Spectrum Disorders: A Follow-Up Study

    ERIC Educational Resources Information Center

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Massagli, Angelo

    2014-01-01

    Background: The Picture Exchange Communication System (PECS) is a popular augmentative communication system frequently used with "nonverbal" children with autism. Several studies suggested that PECS could represent an effective tool for promoting improvement of several social-communicative skills. Only sparse evidence is instead…

  3. Long-Term Effects of PECS on Social-Communicative Skills of Children with Autism Spectrum Disorders: A Follow-Up Study

    ERIC Educational Resources Information Center

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Massagli, Angelo

    2014-01-01

    Background: The Picture Exchange Communication System (PECS) is a popular augmentative communication system frequently used with "nonverbal" children with autism. Several studies suggested that PECS could represent an effective tool for promoting improvement of several social-communicative skills. Only sparse evidence is instead…

  4. Effectiveness of the Picture Exchange Communication System (PECS) on Communication and Speech for Children with Autism Spectrum Disorders: A Meta-Analysis

    ERIC Educational Resources Information Center

    Flippin, Michelle; Reszka, Stephanie; Watson, Linda R.

    2010-01-01

    Purpose: The Picture Exchange Communication System (PECS) is a popular communication-training program for young children with autism spectrum disorders (ASD). This meta-analysis reviews the current empirical evidence for PECS in affecting communication and speech outcomes for children with ASD. Method: A systematic review of the literature on PECS…

  5. "Brief Report: Increase in Production of Spoken Words in Some Children with Autism after PECS Teaching to Phase III"

    ERIC Educational Resources Information Center

    Carr, Deborah; Felce, Janet

    2007-01-01

    The context for this work was an evaluation study [Carr, D., & Felce, J. A. (in press)] of the early phases of the Picture Exchange Communication System (PECS) [Frost, L. A., & Bondy, A. S. (1994). "The picture exchange communication system training manual." Cherry Hill, NJ: Pyramid Educational Consultants, Inc.; Frost, L. A., & Bondy, A. S.…

  6. Comparative Efficacy of the Picture Exchange Communication System (PECS) versus a Speech-Generating Device: Effects on Requesting Skills

    ERIC Educational Resources Information Center

    Boesch, Miriam C.; Wendt, Oliver; Subramanian, Anu; Hsu, Ning

    2013-01-01

    An experimental, single-subject research study investigated the comparative efficacy of the Picture Exchange Communication System (PECS) versus a speech-generating device (SGD) in developing requesting skills for three elementary-age children with severe autism and little to no functional speech. Results demonstrated increases in requesting…

  7. Inhibition of cholinesterase activity by soil extracts and predicted environmental concentrations (PEC) to select relevant pesticides in polluted soils.

    PubMed

    Meza, Juan C Sanchez; Perez, Pedro Avila; Salin, Manuel Borja; Salazar, Victor F Pacheco; Lapoint, Tom

    2010-04-01

    The correlation of predicted environmental concentrations (PEC) with cholinesterase activity inhibition detected in soil extracts was determined. PEC was derived from organophosphate (OP) and carbamate (CA) compounds applied to a flower crop area. Samples of surface soil (0 - 30 cm in depth) and subsurface soil (30 to 60 cm in depth) were taken from a flower crop area in which OP pesticides such as acephate ((RS)-N-[methoxy(methylthio)phosphinoyl]acetamide), dimethoate (2-dimethoxyphosphinothioylthio-N-methylacetamide) and methyl parathion (O,O-dimethyl O-4-nitrophenyl phosphorothioate), and CA pesticides such as carbendazim (methyl benzimidazol-2-ylcarbamate), carbofuran (2,3-dihydro-2,2-dimethylbenzofuran-7-yl methylcarbamate) and methomyl (S-methyl (EZ)-N-(methylcarbamoyloxy) thioacetimidate) were applied for two years. Weekly loads of these pesticides were registered to estimate the annual load of each compound. Physicochemical analysis and relative inhibition of cholinesterasic activity were measured for each soil sample. PEC values were estimated with Pesticide Analytical Model (PESTAN), a leach model, for each pesticide using soil sample data obtained from physicochemical analysis. From all pesticides tested, only acephate and methomyl showed a significant correlation (p < 0.01) between PEC values and inhibition cholinesterase activity of soil extracts. These results suggest that inhibition of cholinesterase activity observed in soil extracts is produced mainly by these two pesticides. Further studies could be developed to measure acephate and methomyl concentrations to reduce their environmental impact.

  8. Mixed Body/Hand Reference Frame for Reaching in 3D Space in Macaque Parietal Area PEc.

    PubMed

    Piserchia, Valentina; Breveglieri, Rossella; Hadjidimitrakis, Kostas; Bertozzi, Federica; Galletti, Claudio; Fattori, Patrizia

    2017-03-01

    The neural correlates of coordinate transformations from vision to action are expressed in the activity of posterior parietal cortex (PPC). It has been demonstrated that among the medial-most areas of the PPC, reaching targets are represented mainly in hand-centered coordinates in area PE, and in eye-centered, body-centered, and mixed body/hand-centered coordinates in area V6A. Here, we assessed whether neurons of area PEc, located between V6A and PE in the medial PPC, encode targets in body-centered, hand-centered, or mixed frame of reference during planning and execution of reaching. We studied 104 PEc cells in 3 Macaca fascicularis. The animals performed a reaching task toward foveated targets located at different depths and directions in darkness, starting with the hand from 2 positions located at different depths, one next to the trunk and the other far from it. We show that most PEc neurons encoded targets in a mixed body/hand-centered frame of reference. Although the effect of hand position was often rather strong, it was not as strong as reported previously in area PE. Our results suggest that area PEc represents an intermediate node in the gradual transformation from vision to action that takes place in the reaching network of the dorsomedial PPC. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  9. "Brief Report: Increase in Production of Spoken Words in Some Children with Autism after PECS Teaching to Phase III"

    ERIC Educational Resources Information Center

    Carr, Deborah; Felce, Janet

    2007-01-01

    The context for this work was an evaluation study [Carr, D., & Felce, J. A. (in press)] of the early phases of the Picture Exchange Communication System (PECS) [Frost, L. A., & Bondy, A. S. (1994). "The picture exchange communication system training manual." Cherry Hill, NJ: Pyramid Educational Consultants, Inc.; Frost, L. A., & Bondy, A. S.…

  10. Partitionable-space enhanced coagulation (PEC) reactor and its working mechanism: a new prospective chemical technology for phosphorus pollution control.

    PubMed

    Zhang, Meng; Zheng, Ping; Abbas, Ghulam; Chen, Xiaoguang

    2014-02-01

    Phosphorus pollution control and phosphorus recycling, simultaneously, are focus of attention in the wastewater treatment. In this work, a novel reactor named partitionable-space enhanced coagulation (PEC) was invented for phosphorus control. The working performance and process mechanism of PEC reactor were investigated. The results showed that the PEC technology was highly efficient and cost-effective. The volumetric removal rate (VRR) reached up to 2.86 ± 0.04 kg P/(m(3) d) with a phosphorus removal rate of over 97%. The precipitant consumption was reduced to 2.60-2.76 kg Fe(II)/kg P with low operational cost of $ 0.632-0.673/kg P. The peak phosphorus content in precipitate was up to 30.44% by P2O5, which reveal the benefit of the recycling phosphorus resource. The excellent performance of PEC technology was mainly attributed to the partitionable-space and 'flocculation filter'. The partition limited the trans-regional back-mixing of reagents along the reactor, which promoted the precipitation reaction. The 'flocculation filter' retained the microflocs, enhancing the flocculation process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Novel Pathways Revealed in Bursa of Fabricius Transcriptome in Response to Extraintestinal Pathogenic Escherichia coli (ExPEC) Infection

    PubMed Central

    Sun, Hongyan; Liu, Peng; Nolan, Lisa K.; Lamont, Susan J.

    2015-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) has major negative impacts on human and animal health. Recent research suggests food-borne links between human and animal ExPEC diseases with particular concern for poultry contaminated with avian pathogenic E. coli (APEC), the avian ExPEC. APEC is also a very important animal pathogen, causing colibacillosis, one of the world’s most widespread bacterial diseases of poultry. Previous studies showed marked atrophy and lymphocytes depletion in the bursa during APEC infection. Thus, a more comprehensive understanding of the avian bursa response to APEC infection will facilitate genetic selection for disease resistance. Four-week-old commercial male broiler chickens were infected with APEC O1 or given saline as a control. Bursas were collected at 1 and 5 days post-infection (dpi). Based on lesion scores of liver, pericardium and air sacs, infected birds were classified as having mild or severe pathology, representing resistant and susceptible phenotypes, respectively. Twenty-two individual bursa RNA libraries were sequenced, each yielding an average of 27 million single-end, 100-bp reads. There were 2469 novel genes in the total of 16,603 detected. Large numbers of significantly differentially expressed (DE) genes were detected when comparing susceptible and resistant birds at 5 dpi, susceptible and non-infected birds at 5 dpi, and susceptible birds at 5 dpi and 1 dpi. The DE genes were associated with signal transduction, the immune response, cell growth and cell death pathways. These data provide considerable insight into potential mechanisms of resistance to ExPEC infection, thus paving the way to develop strategies for ExPEC prevention and treatment, as well as enhancing innate resistance by genetic selection in animals. PMID:26556806

  12. The enhanced PC and PEC oxidation of formic acid in aqueous solution using a Cu-TiO2/ITO film.

    PubMed

    He, Chun; Li, Xiangzhong; Xiong, Ya; Zhu, Xihai; Liu, Shaorong

    2005-01-01

    The photocatalytic (PC) and photoelectrocatalytic (PEC) activity of Cu-TiO2/ITO films for degrading formic acid in aqueous solution was investigated in this study. Compared with a TiO2/ITO film, the degradation efficiency of formic acid on the Cu-TiO2 films increased markedly in both the PC and PEC oxidation processes. However, it was found that the photodeposited Cu metal on the Cu-TiO2 films could electrochemically dissolute during the PEC reaction, while an electrical bias with the voltage higher than 1.48 V was applied. It is believed this is a common problem occurred for several metals deposition on the TiO2 films, which results in a poor stability of the metal-deposited TiO2 electrode in PEC processes. To improve the stability of the Cu-TiO2 electrode, an alternative process between PC and PEC reactions was investigated. It was found that the dissolute Cu metal during the PEC process was re-deposited on the Cu-TiO2 film again during the PC process. The experiments with repeated runs demonstrated that this alternative process could not only overcome the loss of Cu, but also enhance the PEC oxidation efficiency of the Cu-TiO2 films.

  13. RETRACTION: Surface impedance determination of an object located over a planar PEC surface and its use in shape reconstruction Surface impedance determination of an object located over a planar PEC surface and its use in shape reconstruction

    NASA Astrophysics Data System (ADS)

    Seda Ünal, Gül; Yapar, Ali; Akduman, Ibrahim

    2009-06-01

    This paper has substantial overlap with the paper 'Reconstruction of surface impedance of an object located over a planar PEC surface' by Gül Seda Ünal, Mehmet Çayören and Evrim Tetik (2008 Journal of Physics: Conference Series 135 012099). Therefore this article has been retracted by IOP Publishing and by the authors, Gül Seda Ünal, Ali Yapar and Ibrahim Akduman.

  14. Genetic analysis of maintenance of pEC156, a naturally occurring Escherichia coli plasmid that carries genes of the EcoVIII restriction-modification system.

    PubMed

    Werbowy, Olesia; Boratynski, Robert; Dekowska, Agnieszka; Kaczorowski, Tadeusz

    2015-01-01

    In the present study the role of the mechanisms responsible for maintenance of a natural plasmid pEC156, that carries genes of the EcoVIII restriction-modification system was investigated. Analysis of this plasmid's genetic content revealed the presence of genetic determinants suggesting two such mechanisms. The first of them relies on site specific recombination utilizing the Xer/cer molecular machinery, while the second involves a restriction-modification system as an addiction module. Our analysis indicated that three factors affect the maintenance of pEC156: (i) a cis-acting cer site involved in resolution of plasmid multimers, (ii) a gene coding for EcoVIII endonuclease, and (iii) plasmid copy number control. The lowest stability was observed with pEC156 derivatives deprived of the cer site. Decreased stability of pEC156 derivatives was also observed in E.coli strains deficient in genes coding for proteins involved in plasmid multimer resolution (XerC, XerD, ArgR and PepA). A similar effect, but to a much lesser extent was observed for the pEC156 derivative without a functional gene coding for EcoVIII endonuclease. Our results indicate that the presence of the cer site is more important for pEC156 stable maintenance than the presence of a functional gene coding for EcoVIII endonuclease. In our work we also tested maintenance of pEC156 possessing a ColE1-type replicon in bacteria belonging to Enterobacteriaceae family. We have found that pEC156 was most stably maintained in Enterobacter cloacae and Klebsiella oxytoca representing coli-type enterobacteria. We have found that in all enterobacteria tested pEC156 derivatives deficient in the cer site were significantly less stably maintained than cer(+) variants.

  15. The PECS II block as a major analgesic component for clavicle operations: A description of 7 case reports.

    PubMed

    Schuitemaker R, J B; Sala-Blanch, X; Rodriguez-Pérez, C L; Mayoral R, J T; López-Pantaleon, L A; Sánchez-Cohen, A P

    2017-05-26

    Clavicle fractures correspond to 35% of traumatic fractures of the shoulder girdle. Regional anaesthesia has shown better analgesic results than systemic treatment for perioperative management. Innervation of the clavicle is complex, at present its knowledge raises controversy. The lateral pectoral nerve through the innervating musculature predominantly participates in the lateral and anterior part of the clavicle. The following report of 7 cases describes the effective postoperative analgesia of modified PEC II block in patients with middle third clavicle fracture or acromioclavicular dislocation who underwent a modified PEC II block for postoperative pain management, in the context of a multimodal analgesia. The potential advantage of this management over other analgesic procedures should be evaluated in specific clinical trials. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  16. Understanding the brain-behaviour relationship in persons with ASD: implications for PECS as a treatment choice.

    PubMed

    Ogletree, Billy T; Morrow-Odom, K Leigh; Westling, David

    2015-04-01

    This article presents emerging neurological findings in Autism Spectrum Disorders (ASD) with particular attention to how this information might inform treatment practices addressing communication impairments. The article begins with a general discussion of the brain-behaviour relationship and moves to the presentation of recent research findings related to ASD. There is particular attention to individuals with autism who are either non-verbal or present emergent verbal abilities. A specific communication treatment, the Picture Exchange Communication System (PECS), is presented as an example of an intervention that addresses the learner needs of many individuals with ASD. The success of PECS is discussed within the context of its fit with brain-based learner characteristics.

  17. [Machinery and mechanical eroticism. A study on the phenomenology of schizophrenia in two painters' artworks in the Reuter Collection (Pecs)].

    PubMed

    Simon, Mária

    2010-01-01

    In this essay, I introduce two schizophrenic artists from the Reuter's Psychopathological Art Collection (Pecs, Hungary), who had been treated in the 1920es.One artist drew a number of sketches of machines; the other created a serial of mechanically erotic pictures. Pictures are analyzed from an intersubjective-phenomenological perspective. Schizophrenic patients' subjective experiences i.e. the experience of reification as well as the intrusivity and uncontrollability of sexuality are particularly emphasized.

  18. Selection of words for implementation of the Picture Exchange Communication System - PECS in non-verbal autistic children.

    PubMed

    Ferreira, Carine; Bevilacqua, Monica; Ishihara, Mariana; Fiori, Aline; Armonia, Aline; Perissinoto, Jacy; Tamanaha, Ana Carina

    2017-03-09

    It is known that some autistic individuals are considered non-verbal, since they are unable to use verbal language and barely use gestures to compensate for the absence of speech. Therefore, these individuals' ability to communicate may benefit from the use of the Picture Exchange Communication System - PECS. The objective of this study was to verify the most frequently used words in the implementation of PECS in autistic children, and on a complementary basis, to analyze the correlation between the frequency of these words and the rate of maladaptive behaviors. This is a cross-sectional study. The sample was composed of 31 autistic children, twenty-five boys and six girls, aged between 5 and 10 years old. To identify the most frequently used words in the initial period of implementation of PECS, the Vocabulary Selection Worksheet was used. And to measure the rate of maladaptive behaviors, we applied the Autism Behavior Checklist (ABC). There was a significant prevalence of items in the category "food", followed by "activities" and "beverages". There was no correlation between the total amount of items identified by the families and the rate of maladaptive behaviors. The categories of words most mentioned by the families could be identified, and it was confirmed that the level of maladaptive behaviors did not interfere directly in the preparation of the vocabulary selection worksheet for the children studied.

  19. Fast Numerical Algorithms for 3-D Scattering from PEC and Dielectric Random Rough Surfaces in Microwave Remote Sensing

    NASA Astrophysics Data System (ADS)

    Zhang, Lisha

    We present fast and robust numerical algorithms for 3-D scattering from perfectly electrical conducting (PEC) and dielectric random rough surfaces in microwave remote sensing. The Coifman wavelets or Coiflets are employed to implement Galerkin's procedure in the method of moments (MoM). Due to the high-precision one-point quadrature, the Coiflets yield fast evaluations of the most off-diagonal entries, reducing the matrix fill effort from O(N2) to O( N). The orthogonality and Riesz basis of the Coiflets generate well conditioned impedance matrix, with rapid convergence for the conjugate gradient solver. The resulting impedance matrix is further sparsified by the matrix-formed standard fast wavelet transform (SFWT). By properly selecting multiresolution levels of the total transformation matrix, the solution precision can be enhanced while matrix sparsity and memory consumption have not been noticeably sacrificed. The unified fast scattering algorithm for dielectric random rough surfaces can asymptotically reduce to the PEC case when the loss tangent grows extremely large. Numerical results demonstrate that the reduced PEC model does not suffer from ill-posed problems. Compared with previous publications and laboratory measurements, good agreement is observed.

  20. APPLYING TO THE PEC: A CASE HISTORY - A WALK THROUGH THE PROCEDURE FOR APPLYING FOR EQUIVALENCY USING A RECENT CANDIDATE AS A TRUE EXAMPLE.

    EPA Science Inventory

    The USEPA's Pathogen Equivalency Committee (PEC) is entrusted by its Office of Water to critically evaluate innovative and alternative sludge disinfection processes and make recommendations about their Process to Significantly Reduce Pathogens (PSRP) or Process to Further Reduce ...

  1. APPLYING TO THE PEC: A CASE HISTORY - A WALK THROUGH THE PROCEDURE FOR APPLYING FOR EQUIVALENCY USING A RECENT CANDIDATE AS A TRUE EXAMPLE.

    EPA Science Inventory

    The USEPA's Pathogen Equivalency Committee (PEC) is entrusted by its Office of Water to critically evaluate innovative and alternative sludge disinfection processes and make recommendations about their Process to Significantly Reduce Pathogens (PSRP) or Process to Further Reduce ...

  2. Meta-analysis of PECS with individuals with ASD: investigation of targeted versus non-targeted outcomes, participant characteristics, and implementation phase.

    PubMed

    Ganz, Jennifer B; Davis, John L; Lund, Emily M; Goodwyn, Fara D; Simpson, Richard L

    2012-01-01

    The Picture Exchange Communication System (PECS) is a widely used picture/icon aided augmentative communication system designed for learners with autism and other developmental disorders. This meta-analysis analyzes the extant empirical literature for PECS relative to targeted (functional communication) and non-targeted concomitant outcomes (behavior, social skills, and speech) for learners with autism, learners with autism and intellectual disabilities and those with autism and multiple disabilities. Effect size analyses were done using the Improvement Rate Difference method, an advanced metric. Effect sizes were independently analyzed for targeted and non-targeted outcomes, student age, learner disability, and number of phases in the PECS protocol acquired by learners. Results supported the judgment that PECS is a promising intervention method. Analysis also revealed that functional communication outcomes associated with the PECS protocol were most impacted, that preschool children and those with autism generally showed the strongest training effects, and that in general students who advanced through the most PECS protocol phases had the best outcomes.

  3. Long-term effects of PECS on social-communicative skills of children with autism spectrum disorders: a follow-up study.

    PubMed

    Lerna, Anna; Esposito, Dalila; Conson, Massimiliano; Massagli, Angelo

    2014-01-01

    The Picture Exchange Communication System (PECS) is a popular augmentative communication system frequently used with 'nonverbal' children with autism. Several studies suggested that PECS could represent an effective tool for promoting improvement of several social-communicative skills. Only sparse evidence is instead available on the long-term effectiveness of this treatment system. To test the long-term effects of PECS, for which a follow-up study was conducted by assessing social-communicative skills in nonverbal preschool children with autism after 12 months from treatment completion. Two groups of children (N = 14) were assessed; one group had completed the PECS training and the other conventional language therapy (CLT). At follow-up all children received the same pre- and post-treatment assessment. Outcome measures were the following: Communication and Social domains of Autism Diagnostic Observation Schedule (ADOS); Language and Personal-Social subscales of the Griffiths' Mental Developmental Scales (GMDS); Communication and Social Abilities domains of the Vineland Adaptive Behavior Scales (VABS); and several social-communicative variables coded in an unstructured setting. The PECS group showed significant improvements compared with the CLT group on ADOS severity scores (Communication, Social and Total), on GMDS Social domain and on VABS Communication and Social domains. PECS-related gains on the VABS Social domain and on specific social-communicative measures coded during free-play, i.e. frequency of joint attention and initiation, and duration of cooperative play, were stable after 1-year follow-up. Cooperative play continued to improve on follow-up with respect to both post- and pre-treatment assessment. These findings demonstrated that PECS training can promote long-term enhancement of specific socio-communicative skills in children with autism. © 2014 Royal College of Speech and Language Therapists.

  4. Pesticide volatilization from plants: improvement of the PEC model PELMO based on a boundary-layer concept.

    PubMed

    Wolters, André; Leistra, Minze; Linnemann, Volker; Klein, Michael; Schäffer, Andreas; Vereecken, Harry

    2004-05-15

    Calculation of pesticide volatilization from plants as an integral component of pesticide fate models is of utmost importance, especially as part of PEC (predicted environmental concentrations) models used in the registration procedures for pesticides. A mechanistic approach using a laminar air-boundary layer concept to predict volatilization from plant surfaces was compared to data obtained in a wind-tunnel study after simultaneous application of parathion-methyl, fenpropimorph, and quinoxyfen to winter wheat. Parathion-methyl was shown to have the highest volatilization during the wind-tunnel study of 10 days (29.2%). Volatilization of quinoxyfen was about 15.0%, revealing a higher volatilization tendency than fenpropimorph (6.0%), which is attributed to enhanced penetration of fenpropimorph counteracting volatilization. Predictions of the boundary-layer approach were markedly influenced by the selected values for the equivalent thickness of the boundary layer and rate coefficients, thus indicating that future improvements of the approach will require a deeper understanding of the kinetics of the underlying processes, e.g. phototransformation and penetration. The boundary-layer volatilization module was included in the European registration model PELMO, enabling simultaneous calculation of volatilization from plants and soil. Application of PELMO to experimental findings were the first comprehensive PEC model calculations to imply the relevant processes affecting the postapplication fate of pesticides.

  5. Ports of Mucuripe and Pecém, Ceará, Brazil: restructuring process and its impact on workers' health.

    PubMed

    Maciel, Regina Heloisa; Fontenelle, Marselle Fernandes; Gonçalves, Rosemary Cavalcante; Lopes, Taise Araújo; Moura, Tuany Maria Sousa; Monteiro, Felipe Mendes

    2012-01-01

    This paper presents a comparative study of working conditions and health hazards of two ports in the state of Ceará: Mucuripe and Pecém, focusing workers in the various categories involved in the operational activities of the two ports. The aim is to investigate changes implemented by the restructuring process of ports arising from the Port Modernization Act. In the case of Ceará, the organization and control of work at the mentioned ports occur differently: Mucuripe, the oldest port, had to adapt to the changes enforced by the Modernization Act and Pecém, called Port Terminal, inaugurated in 2001, "was born modern". To achieve our objective, we carried out field work, using Ergonomic Work Analysis. Systematic observations were made of the various activities carried out by workers, as well as interviews with managers, workers and trade unionists. Container operations and other activities of the two ports were recorded in film and presented to groups of workers (focus groups) in order to better understand work organization and the main differences in tasks carried out in the two ports. Each reality presents different characteristics regarding port operations, type of work and labor control. Results indicate that due to the technological innovations, the restructuring process reduced some risks, but brought new occupational hazards and intensification of work.

  6. Synergizing the multiple plasmon resonance coupling and quantum effects to obtain enhanced SERS and PEC performance simultaneously on a noble metal-semiconductor substrate.

    PubMed

    Yang, Tao; Liu, Wenna; Li, Lidong; Chen, Junhong; Hou, Xinmei; Chou, Kuo-Chih

    2017-02-09

    Aiming to achieve the synergistic enhancement of the surface-enhanced Raman scattering (SERS) and photoelectrocatalytic (PEC) performance on a noble metal-semiconductor, such as Au nanoparticles (NPs)-TiO2 nanotube arrays (TiO2 NTAs@hybrid Au NPs), theoretical calculation and experiments are performed. Theoretical calculation indicates that both the SERS and PEC performance can be enhanced by coupling different sized Au NPs on TiO2 NTAs based on synergizing the multiple plasmon resonance coupling and quantum effects. To further verify this mechanism, TiO2 NTAs@hybrid Au NPs are assembled via synthesis of TiO2 NTAs through the anodic oxidation process, followed by the deposition of different sized Au NPs onto the TiO2 surface simultaneously using physical vapor deposition (PVD) in this work. Such substrates exhibit excellent detection sensitivity towards organic dyes including Rhodamine B (RhB), the organic herbicide dichlorophenoxyacetic acid (2,4-D) and the organophosphate pesticide methyl-parathion (MP) with high reproducibility, stability and reusability. Meanwhile the PEC performance based on this substrate remains efficient compared with the reported results in the literature. The efficient PEC performance mainly originates from both the quantum effect of Au nanoparticles and the formation of a metal-semiconductor heterojunction. It is proposed that other noble metal-semiconductor complex nanomaterials can also obtain both enhanced SERS and PEC performance based on the above mechanism.

  7. A novel method developed for estimating mineralization efficiencies and its application in PC and PEC degradations of large molecule biological compounds with unknown chemical formula.

    PubMed

    Li, Guiying; Liu, Xiaolu; An, Taicheng; Wong, Po Keung; Zhao, Huijun

    2016-05-15

    A new method to estimate the photocatalytic (PC) and photoelectrocatalytic (PEC) mineralization efficiencies of large molecule biological compounds with unknown chemical formula in water was firstly developed and experimentally validated. The method employed chemical oxidation under the standard dichromate chemical oxygen demand (COD) conditions to obtain QCOD values of model compounds with unknown chemical formula. The measured QCOD values were used as the reference to replace QCOD values of model compounds for calculation of the mineralization efficiencies (in %) by assuming the obtained QCOD values are the measure of the theoretical charge required for the complete mineralization of organic pollutants. Total organic carbon (TOC) was also employed as a reference to confirm the mineralization capacity of dichromate chemical oxidation. The developed method was applied to determine the degradation extent of model compounds, such as bovine serum albumin (BSA), lecithin and bacterial DNA, by PC and PEC. Incomplete PC mineralization of all large molecule biological compounds was observed, especially for BSA. But the introduction of electrochemical technique into a PC oxidation process could profoundly improve the mineralization efficiencies of model compounds. PEC mineralization efficiencies of bacterial DNA was the highest, while that of lecithin was the lowest. Overall, PEC degradation method was found to be much effective than PC method for all large molecule biological compounds investigated, with PEC/PC mineralization ratios followed an order of BSA > lecithin > DNA.

  8. Plasmid pEC156, a Naturally Occurring Escherichia coli Genetic Element That Carries Genes of the EcoVIII Restriction-Modification System, Is Mobilizable among Enterobacteria

    PubMed Central

    Werbowy, Olesia; Kaczorowski, Tadeusz

    2016-01-01

    Type II restriction-modification systems are ubiquitous in prokaryotes. Some of them are present in naturally occurring plasmids, which may facilitate the spread of these systems in bacterial populations by horizontal gene transfer. However, little is known about the routes of their dissemination. As a model to study this, we have chosen an Escherichia coli natural plasmid pEC156 that carries the EcoVIII restriction modification system. The presence of this system as well as the cis-acting cer site involved in resolution of plasmid multimers determines the stable maintenance of pEC156 not only in Escherichia coli but also in other enterobacteria. We have shown that due to the presence of oriT-type F and oriT-type R64 loci it is possible to mobilize pEC156 by conjugative plasmids (F and R64, respectively). The highest mobilization frequency was observed when pEC156-derivatives were transferred between Escherichia coli strains, Enterobacter cloacae and Citrobacter freundii representing coliform bacteria. We found that a pEC156-derivative with a functional EcoVIII restriction-modification system was mobilized in enterobacteria at a frequency lower than a plasmid lacking this system. In addition, we found that bacteria that possess the EcoVIII restriction-modification system can efficiently release plasmid content to the environment. We have shown that E. coli cells can be naturally transformed with pEC156-derivatives, however, with low efficiency. The transformation protocol employed neither involved chemical agents (e.g. CaCl2) nor temperature shift which could induce plasmid DNA uptake. PMID:26848973

  9. Development of in vitro models to demonstrate the ability of PecSys®, an in situ nasal gelling technology, to reduce nasal run-off and drip.

    PubMed

    Castile, Jonathan; Cheng, Yu-Hui; Simmons, Ben; Perelman, Michael; Smith, Alan; Watts, Peter

    2013-05-01

    Many of the increasing number of intranasal products available for either local or systemic action can be considered sub-optimal, most notably where nasal drip or run-off give rise to discomfort/tolerability issues or reduced/variable efficacy. PecSys, an in situ gelling technology, contains low methoxy (LM) pectin which gels due to interaction with calcium ions present in nasal fluid. PecSys is designed to spray readily, only forming a gel on contact with the mucosal surface. The present study employed two in vitro models to confirm that gelling translates into a reduced potential for drip/run-off: (i) Using an inclined TLC plate treated with a simulated nasal electrolyte solution (SNES), mean drip length [±SD, n = 10] was consistently much shorter for PecSys (1.5 ± 0.4 cm) than non-gelling control (5.8 ± 1.6 cm); (ii) When PecSys was sprayed into a human nasal cavity cast model coated with a substrate containing a physiologically relevant concentration of calcium, PecSys solution was retained at the site of initial deposition with minimal redistribution, and no evidence of run-off/drip anteriorly or down the throat. In contrast, non-gelling control was significantly more mobile and consistently redistributed with run-off towards the throat. In both models PecSys significantly reduced the potential for run-off/drip ensuring that more solution remained at the deposition site. In vivo, this enhancement of retention will provide optimum patient acceptability, modulate drug absorption and maximize the ability of drugs to be absorbed across the nasal mucosa and thus reduce variability in drug delivery.

  10. Development of in vitro models to demonstrate the ability of PecSys®, an in situ nasal gelling technology, to reduce nasal run-off and drip

    PubMed Central

    2013-01-01

    Many of the increasing number of intranasal products available for either local or systemic action can be considered sub-optimal, most notably where nasal drip or run-off give rise to discomfort/tolerability issues or reduced/variable efficacy. PecSys, an in situ gelling technology, contains low methoxy (LM) pectin which gels due to interaction with calcium ions present in nasal fluid. PecSys is designed to spray readily, only forming a gel on contact with the mucosal surface. The present study employed two in vitro models to confirm that gelling translates into a reduced potential for drip/run-off: (i) Using an inclined TLC plate treated with a simulated nasal electrolyte solution (SNES), mean drip length [±SD, n = 10] was consistently much shorter for PecSys (1.5 ± 0.4 cm) than non-gelling control (5.8 ± 1.6 cm); (ii) When PecSys was sprayed into a human nasal cavity cast model coated with a substrate containing a physiologically relevant concentration of calcium, PecSys solution was retained at the site of initial deposition with minimal redistribution, and no evidence of run-off/drip anteriorly or down the throat. In contrast, non-gelling control was significantly more mobile and consistently redistributed with run-off towards the throat. Conclusion In both models PecSys significantly reduced the potential for run-off/drip ensuring that more solution remained at the deposition site. In vivo, this enhancement of retention will provide optimum patient acceptability, modulate drug absorption and maximize the ability of drugs to be absorbed across the nasal mucosa and thus reduce variability in drug delivery. PMID:22803832

  11. Numerical algorithms based on Galerkin methods for the modeling of reactive interfaces in photoelectrochemical (PEC) solar cells

    NASA Astrophysics Data System (ADS)

    Harmon, Michael; Gamba, Irene M.; Ren, Kui

    2016-12-01

    This work concerns the numerical solution of a coupled system of self-consistent reaction-drift-diffusion-Poisson equations that describes the macroscopic dynamics of charge transport in photoelectrochemical (PEC) solar cells with reactive semiconductor and electrolyte interfaces. We present three numerical algorithms, mainly based on a mixed finite element and a local discontinuous Galerkin method for spatial discretization, with carefully chosen numerical fluxes, and implicit-explicit time stepping techniques, for solving the time-dependent nonlinear systems of partial differential equations. We perform computational simulations under various model parameters to demonstrate the performance of the proposed numerical algorithms as well as the impact of these parameters on the solution to the model.

  12. Enhanced PEC performance of nanoporous Si photoelectrodes by covering HfO2 and TiO2 passivation layers

    NASA Astrophysics Data System (ADS)

    Xing, Zhuo; Ren, Feng; Wu, Hengyi; Wu, Liang; Wang, Xuening; Wang, Jingli; Wan, Da; Zhang, Guozhen; Jiang, Changzhong

    2017-03-01

    Nanostructured Si as the high efficiency photoelectrode material is hard to keep stable in aqueous for water splitting. Capping a passivation layer on the surface of Si is an effective way of protecting from oxidation. However, it is still not clear in the different mechanisms and effects between insulating oxide materials and oxide semiconductor materials as passivation layers. Here, we compare the passivation effects, the photoelectrochemical (PEC) properties, and the corresponding mechanisms between the HfO2/nanoporous-Si and the TiO2/nanoporous-Si by I-V curves, Motte-schottky (MS) curves, and electrochemical impedance spectroscopy (EIS). Although the saturated photocurrent densities of the TiO2/nanoporous Si are lower than that of the HfO2/nanoporous Si, the former is more stable than the later.

  13. Enhanced PEC performance of nanoporous Si photoelectrodes by covering HfO2 and TiO2 passivation layers.

    PubMed

    Xing, Zhuo; Ren, Feng; Wu, Hengyi; Wu, Liang; Wang, Xuening; Wang, Jingli; Wan, Da; Zhang, Guozhen; Jiang, Changzhong

    2017-03-02

    Nanostructured Si as the high efficiency photoelectrode material is hard to keep stable in aqueous for water splitting. Capping a passivation layer on the surface of Si is an effective way of protecting from oxidation. However, it is still not clear in the different mechanisms and effects between insulating oxide materials and oxide semiconductor materials as passivation layers. Here, we compare the passivation effects, the photoelectrochemical (PEC) properties, and the corresponding mechanisms between the HfO2/nanoporous-Si and the TiO2/nanoporous-Si by I-V curves, Motte-schottky (MS) curves, and electrochemical impedance spectroscopy (EIS). Although the saturated photocurrent densities of the TiO2/nanoporous Si are lower than that of the HfO2/nanoporous Si, the former is more stable than the later.

  14. Enhanced PEC performance of nanoporous Si photoelectrodes by covering HfO2 and TiO2 passivation layers

    PubMed Central

    Xing, Zhuo; Ren, Feng; Wu, Hengyi; Wu, Liang; Wang, Xuening; Wang, Jingli; Wan, Da; Zhang, Guozhen; Jiang, Changzhong

    2017-01-01

    Nanostructured Si as the high efficiency photoelectrode material is hard to keep stable in aqueous for water splitting. Capping a passivation layer on the surface of Si is an effective way of protecting from oxidation. However, it is still not clear in the different mechanisms and effects between insulating oxide materials and oxide semiconductor materials as passivation layers. Here, we compare the passivation effects, the photoelectrochemical (PEC) properties, and the corresponding mechanisms between the HfO2/nanoporous-Si and the TiO2/nanoporous-Si by I–V curves, Motte-schottky (MS) curves, and electrochemical impedance spectroscopy (EIS). Although the saturated photocurrent densities of the TiO2/nanoporous Si are lower than that of the HfO2/nanoporous Si, the former is more stable than the later. PMID:28252106

  15. Improved charge transportation at PbS QDs/TiO2 interface for efficient PEC hydrogen generation.

    PubMed

    Ikram, Ashi; Sahai, Sonal; Rai, Snigdha; Dass, Sahab; Shrivastav, Rohit; Satsangi, Vibha R

    2016-06-21

    The effect of lead sulfide (PbS) quantum dots (QDs) on the photoelectrochemical properties of TiO2 with a varied number of SILAR cycles has been investigated. The study has also highlighted physical processes including band alignment, charge recombination and transportation for a PbS QDs/TiO2 interface. The inclusion of PbS QDs underneath TiO2 thin film has significantly enhanced the PEC response due to a higher number of photogenerated charge carriers along with the efficient separation and facilitation of these carriers towards their respective electrodes. The uniqueness of the work lies in the high stability of the system as PbS QDs lie beneath the TiO2 thin film, compared to the commonly used QDs sensitization over metal oxide, along with a good photoresponse.

  16. ExPEC-typical virulence-associated genes correlate with successful colonization by intestinal E. coli in a small piglet group.

    PubMed

    Schierack, Peter; Walk, Nicole; Ewers, Christa; Wilking, Hendrik; Steinrück, Hartmut; Filter, Matthias; Wieler, Lothar H

    2008-07-01

    Upon studying the transmission of Escherichia coli from a sow to five of her piglets, we observed domination of the coliform flora in piglets by a single E. coli clone, especially after weaning. This haemolytic cloneH1 did not harbour any virulence determinants typical for intestinal pathogenic E. coli isolates from swine but had a virulence gene profile very similar to extraintestinal E. coli (ExPEC), including genes coding for P fimbriae and several iron acquisition systems, besides having an affiliation to the phylogenetic B2 group. Overall, we show that the presence of higher numbers of ExPEC-typical virulence-associated genes (VAGs) in clones correlate with their successful colonization ability in piglets. We conclude that VAGs typical for ExPEC also support intestinal colonization in healthy pigs. Faeces of healthy domestic pigs can harbour high numbers of ExPEC-similar E. coli and are suggested to be a potential risk for the transmission of such bacteria to other hosts.

  17. The Effectiveness of Picture Exchange Communication System (PECS) Training for Teachers of Children with Autism: A Pragmatic, Group Randomised Controlled Trial

    ERIC Educational Resources Information Center

    Howlin, Patricia; Gordon, R. Kate; Pasco, Greg; Wade, Angie; Charman, Tony

    2007-01-01

    Objective: To assess the effectiveness of expert training and consultancy for teachers of children with autism spectrum disorder in the use of the Picture Exchange Communication System (PECS). Method: Design: Group randomised, controlled trial (3 groups: immediate treatment, delayed treatment, no treatment). Participants: 84 elementary school…

  18. Effects of the Picture Exchange Communication System (PECS) on Maladaptive Behavior in Children with Autism Spectrum Disorders (ASD): A Review of the Literature

    ERIC Educational Resources Information Center

    Battaglia, Dana; McDonald, Mary E.

    2015-01-01

    This paper provides an overview of the literature investigating the functional relationship between the use of the Picture Exchange Communication System (PECS) and maladaptive behavior (i.e., aggression, tantrums) in individuals with autism spectrum disorders (ASD). Digital searches were conducted to identify single subject design studies…

  19. Development and Use of Error-Prone Models to Supplement Pre-Established Criteria (PEC) in Selecting Pell Grant Recipients for Validation.

    ERIC Educational Resources Information Center

    Advanced Technology, Inc., Reston, VA.

    The development of a number of error-prone models to select Pell Grant recipients for validation is discussed. The 1983-1984 Pell Grant validation strategy consists of a two-stage approach: selection using Pre-Established Criteria (PEC) followed by selection using Error Prone Modeling (EPM). The database used for model development consists of a…

  20. The Effectiveness of the Picture Exchange Communication System (PECS) for Children with Autism Spectrum Disorder (ASD): A South African Pilot Study

    ERIC Educational Resources Information Center

    Travis, Julia; Geiger, Martha

    2010-01-01

    This study investigated the effects of introducing the Picture Exchange Communication System (PECS) on the frequency of requesting and commenting and the length of verbal utterances of two children with autism spectrum disorder (ASD) who presented with some spoken language, but limited use of language in communicative exchanges. A mixed research…

  1. Genetic organization of a DNA-processing region required for mobilization of a non-self-transmissible plasmid, pEC3, isolated from Erwinia carotovora subsp. carotovora.

    PubMed

    Nomura, N; Yamashita, M; Murooka, Y

    1996-04-17

    A non-self-transmissible multiple-copy plasmid, pEC3, isolated from the phytopathogenic bacterium, Erwinia carotovora subsp. carotovora, can be mobilized by an IncP-type plasmid. The hybrid plasmid vector, pETC3, constructed from pEC3 by fusion to markers conferring TcR and CmR, was transferred by conjugation from Escherichia coli (Ec) to various genera of Enterobacteriaceae and to other genera of Gram(-) bacteria which included Xanthomonas, Agrobacterium and Rhizobium. Deletion analysis and successive subcloning of pEC3 revealed that a cis-acting locus, oriT and a trans-acting locus, mob, were involved in mobilization of pEC3. Five open reading frames (ORFs) were found in the mob region, of which four were identified as mobA, B, C and D. The mobA gene overlapped with mobC, B, D and ORF1 that were transcribed polycistronically from upstream from mobC. The nature of the four products of mob genes, MobA, B, C and D, was verified by use of the T7 promoter system in Ec.

  2. The pectate lyase encoded by the pecCl1 gene is an important determinant for the aggressiveness of Colletotrichum lindemuthianum.

    PubMed

    Cnossen-Fassoni, Andréia; Bazzolli, Denise Mara Soares; Brommonschenkel, Sérgio Hermínio; Fernandes de Araújo, Elza; de Queiroz, Marisa Vieira

    2013-08-01

    Colletotrichum lindemuthianum is the causal agent of anthracnose in the common bean, and the genes that encode its cell-wall-degrading enzymes are crucial for the development of the disease. Pectinases are the most important group of cell wall-degrading enzymes produced by phytopathogenic fungi. The pecC1l gene, which encodes a pectate lyase in C. lindemuthianum, was isolated and characterized. Possible cis-regulatory elements and transcription factor binding sites that may be involved in the regulation of genetic expression were detected in the promoter region of the gene. pecCl1 is represented by a single copy in the genome of C. lindemuthianum, though in silico analyses of the genomes of Colletotrichum graminicola and Colletotrichum higginsianum suggest that the genome of C. lindemuthianum includes other genes that encode pectate lyases. Phylogenetic analysis detected two groups that clustered based on different members of the pectate lyase family. Analysis of the differential expression of pecCl1 during different stages of infection showed a significant increase in pecCl1 expression five days after infection, at the onset of the necrotrophic phase. The split-maker technique proved to be an efficient method for inactivation of the pecCl1 gene, which allowed functional study of a mutant with a site-specific integration. Though gene inactivation did not result in complete loss of pectate lyase activity, the symptoms of anthracnose were reduced. Analysis of pectate lyases might not only contribute to the understanding of anthracnose in the common bean but might also lead to the discovery of an additional target for controlling anthracnose.

  3. Cobalt-Nickel Layered Double Hydroxides Modified on TiO2 Nanotube Arrays for Highly Efficient and Stable PEC Water Splitting.

    PubMed

    Chen, Weijian; Wang, Taotao; Xue, Jiawei; Li, Shikuo; Wang, Zidan; Sun, Song

    2017-03-01

    TiO2 -based photoanodes have attracted extensive attention worldwide for photoelectrochemical (PEC) water splitting, but these materials still suffer from poor electron-hole separation and low photoconversion efficiency. Here, the high PEC water splitting activity and long-term stability against photocorrosion of well-aligned hierarchical TiO2 @CoNi-layered double hydroxides nanotube arrays (TiO2 @CoNi-LDHs NTAs) are reported. The typical TiO2 @CoNi-LDHs NTAs exhibits enhancing photocurrent density of 4.4 mA cm(-2) at a potential of 1.23 V (vs reversible hydrogen electrode) under AM 1.5G simulated sunlight (100 mW cm(-2) ), 3.3 times higher than that of the pristine TiO2 sample. Moreover, this hierarchical electrode displays excellent stability against photocorrosion with initial activity loss no more than 1.0% even after 10 h irradiation in Na2 SO4 electrolyte solution (pH 6.8), much competitive to those reported TiO2 -based photoelectrodes. This work may offer a combinatorial synthesis strategy for the preparation of hierarchical architectures with high PEC performances.

  4. Preparation of Ag doped BiVO4 film and its enhanced photoelectrocatalytic (PEC) ability of phenol degradation under visible light.

    PubMed

    Zhang, Xiufang; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2009-08-15

    Ag particles were doped on BiVO(4) film by photoreduction technique. XRD analysis indicated that the chemical state of the Ag particles was metallic Ag. TEM observation confirmed that the sizes of the Ag particles were 10-20nm. The investigation of the phenol degradation demonstrated that the photocatalytic (PC) degradation rate of the phenol on the Ag doped BiVO(4) film was enhanced by 1.61 times in PC process and by 42.7 times in photoelectrocatalytic (PEC) process compared with that of the BiVO(4) film. The transportation of the electrons from the BiVO(4) to Ag driven by the schottky barrier formed between Ag and BiVO(4) can increase the charge carrier separation, and consequently enhance the PC performance. The enhancement of the PC ability in PEC process could be attributed to the simultaneous movements of the photogenerated electrons to external circuit and the photogenerated holes to the Ag particles deposited on the BiVO(4) film. In 4h, the elimination efficiency and the TOC removal efficiency of phenol on the Ag doped BiVO(4) film in PEC process were 94.1% and 61.0%, respectively.

  5. Coupled optical absorption, charge carrier separation, and surface electrochemistry in surface disordered/hydrogenated TiO2 for enhanced PEC water splitting reaction.

    PubMed

    Behara, Dilip Kumar; Ummireddi, Ashok Kumar; Aragonda, Vidyasagar; Gupta, Prashant Kumar; Pala, Raj Ganesh S; Sivakumar, Sri

    2016-03-28

    The central governing factors that influence the efficiency of photoelectrochemical (PEC) water splitting reaction are photon absorption, effective charge-carrier separation, and surface electrochemistry. Attempts to improve one of the three factors may debilitate other factors and we explore such issues in hydrogenated TiO2, wherein a significant increase in optical absorption has not resulted in a significant increase in PEC performance, which we attribute to the enhanced recombination rate due to the formation of amorphization/disorderness in the bulk during the hydrogenation process. To this end, we report a methodology to increase the charge-carrier separation with enhanced optical absorption of hydrogenated TiO2. Current methodology involves hydrogenation of non-metal (N and S) doped TiO2 which comprises (1) lowering of the band gap through shifting of the valence band via less electronegative non-metal N, S-doping, (2) lowering of the conduction band level and the band gap via formation of the Ti(3+) state and oxygen vacancies by hydrogenation, and (3) material processing to obtain a disordered surface structure which favors higher electrocatalytic (EC) activity. This design strategy yields enhanced PEC activity (%ABPE = 0.38) for the N-S co-doped TiO2 sample hydrogenated at 800 °C for 24 h over possible combinations of N-S co-doped TiO2 samples hydrogenated at 500 °C/24 h, 650 °C/24 h and 800 °C/72 h. This suggests that hydrogenation at lower temperatures does not result in much increase in optical absorption and prolonged hydrogenation results in an increase in optical absorption but a decrease in charge carrier separation by forming disorderness/oxygen vacancies in the bulk. Furthermore, the difference in double layer capacitance (C(dl)) calculated from electrochemical impedance spectroscopy (EIS) measurements of these samples reflects the change in the electrochemical surface area (ECSA) and facilitates assessing the key role of surface

  6. Broiler chickens, broiler chicken meat, pigs and pork as sources of ExPEC related virulence genes and resistance in Escherichia coli isolates from community-dwelling humans and UTI patients.

    PubMed

    Jakobsen, Lotte; Spangholm, Daniel J; Pedersen, Karl; Jensen, Lars B; Emborg, Hanne-Dorthe; Agersø, Yvonne; Aarestrup, Frank M; Hammerum, Anette M; Frimodt-Møller, Niels

    2010-08-15

    Urinary tract infection (UTI) is one of the most common bacterial infections. UTI is primarily caused by extraintestinal pathogenic Escherichia coli (ExPEC) from the patients' own fecal flora. The ExPEC often belong to phylogroups B2 and D, the groups which include potent human ExPEC isolates causing UTI, bacteremia, and meningitis. The external sources of these ExPEC in the human intestine are unknown. The food supply may transmit ExPEC to humans. However, evidence of this hypothesis is limited. To assess this hypothesis, the objective of our study was to investigate the presence of ExPEC related virulence genes in E. coli isolates from UTI patients, community-dwelling humans, meat, and production animals. Accordingly, we included 964 geographically and temporally matched E. coli isolates from UTI patients (n=102), community-dwelling humans (n=109), fresh Danish (n=197) and imported broiler chicken meat (n=86), broiler chickens (n=138), fresh Danish (n=177) and imported pork (n=10), and pigs (n=145) in the study. All isolates were investigated for the presence of eight ExPEC related genes (kpsM II, papA, papC, iutA, sfaS, focG, afa, hlyD) using PCR. To investigate any similarities between isolates from the different origins, we performed a cluster analysis including antimicrobial resistance data previously published. We detected seven of the eight ExPEC related genes in isolates from broiler chicken meat, broiler chickens, pork and pigs. Our findings suggest that broiler chicken meat, broiler chickens, pork and pigs could be the source of strains with these ExPEC related virulence genes in community-dwelling humans and UTI patients. Especially detection of ExPEC related virulence genes in isolates belonging to phylogroups B2 and D is very concerning and may have a significant medical impact. The cluster analysis of virulence gene and antimicrobial resistance profiles showed strong similarities between UTI patient, community-dwelling human isolates, meat, and

  7. Overlapped sequence types (STs) and serogroups of avian pathogenic (APEC) and human extra-intestinal pathogenic (ExPEC) Escherichia coli isolated in Brazil.

    PubMed

    Maluta, Renato Pariz; Logue, Catherine Mary; Casas, Monique Ribeiro Tiba; Meng, Ting; Guastalli, Elisabete Aparecida Lopes; Rojas, Thaís Cabrera Galvão; Montelli, Augusto Cezar; Sadatsune, Teruê; de Carvalho Ramos, Marcelo; Nolan, Lisa Kay; da Silveira, Wanderley Dias

    2014-01-01

    Avian pathogenic Escherichia coli (APEC) strains belong to a category that is associated with colibacillosis, a serious illness in the poultry industry worldwide. Additionally, some APEC groups have recently been described as potential zoonotic agents. In this work, we compared APEC strains with extraintestinal pathogenic E. coli (ExPEC) strains isolated from clinical cases of humans with extra-intestinal diseases such as urinary tract infections (UTI) and bacteremia. PCR results showed that genes usually found in the ColV plasmid (tsh, iucA, iss, and hlyF) were associated with APEC strains while fyuA, irp-2, fepC sitDchrom, fimH, crl, csgA, afa, iha, sat, hlyA, hra, cnf1, kpsMTII, clpVSakai and malX were associated with human ExPEC. Both categories shared nine serogroups (O2, O6, O7, O8, O11, O19, O25, O73 and O153) and seven sequence types (ST10, ST88, ST93, ST117, ST131, ST155, ST359, ST648 and ST1011). Interestingly, ST95, which is associated with the zoonotic potential of APEC and is spread in avian E. coli of North America and Europe, was not detected among 76 APEC strains. When the strains were clustered based on the presence of virulence genes, most ExPEC strains (71.7%) were contained in one cluster while most APEC strains (63.2%) segregated to another. In general, the strains showed distinct genetic and fingerprint patterns, but avian and human strains of ST359, or ST23 clonal complex (CC), presented more than 70% of similarity by PFGE. The results demonstrate that some "zoonotic-related" STs (ST117, ST131, ST10CC, ST23CC) are present in Brazil. Also, the presence of moderate fingerprint similarities between ST359 E. coli of avian and human origin indicates that strains of this ST are candidates for having zoonotic potential.

  8. Surgical excision of the breast giant fibroadenoma under regional anesthesia by Pecs II and internal intercostal plane block: a case report and brief technical description: a case report.

    PubMed

    Kim, Hyungtae; Shim, Junho; Kim, Ikthae

    2017-02-01

    A 22-years-old female patient at 171 cm and 67 kg visited the Department of Breast Surgery of the hospital with a mass accompanied with pain on the left side breast as chief complaints. Since physical examination revealed a suspected huge mass, breast surgeon decided to perform surgical excision and requested anesthesia to our department. Surgery of breast tumor is often under local anesthesia. However, in case of big size tumor, surgery is usually performed under general anesthesia. The patient feared general anesthesia. Unlike abdominal surgery, there is no need to control visceral pain for breast and anterior thoracic wall surgery. Therefore, we decided to perform resection under regional anesthesia. Herein, we report a successful anesthetic and pain management of the patient undergoing excision of a huge breast fibroadenoma under regional anesthesia using Pecs II and internal intercostal plane block.

  9. Surgical excision of the breast giant fibroadenoma under regional anesthesia by Pecs II and internal intercostal plane block: a case report and brief technical description: a case report

    PubMed Central

    Shim, Junho; Kim, Ikthae

    2017-01-01

    A 22-years-old female patient at 171 cm and 67 kg visited the Department of Breast Surgery of the hospital with a mass accompanied with pain on the left side breast as chief complaints. Since physical examination revealed a suspected huge mass, breast surgeon decided to perform surgical excision and requested anesthesia to our department. Surgery of breast tumor is often under local anesthesia. However, in case of big size tumor, surgery is usually performed under general anesthesia. The patient feared general anesthesia. Unlike abdominal surgery, there is no need to control visceral pain for breast and anterior thoracic wall surgery. Therefore, we decided to perform resection under regional anesthesia. Herein, we report a successful anesthetic and pain management of the patient undergoing excision of a huge breast fibroadenoma under regional anesthesia using Pecs II and internal intercostal plane block. PMID:28184271

  10. Correlation between the genomic o454-nlpD region polymorphisms, virulence gene equipment and phylogenetic group of extraintestinal Escherichia coli (ExPEC) enables pathotyping irrespective of host, disease and source of isolation.

    PubMed

    Ewers, Christa; Dematheis, Flavia; Singamaneni, Haritha Devi; Nandanwar, Nishant; Fruth, Angelika; Diehl, Ines; Semmler, Torsten; Wieler, Lothar H

    2014-01-01

    The mutS-rpoS intergenic region in E. coli displays a mosaic structure which revealed pathotype specific patterns. To assess the importance of this region as a surrogate marker for the identification of highly virulent extraintestinal pathogenic E. coli (ExPEC) strains we aimed to: (i) characterize the genetic diversity of the mutS gene and the o454-nlpD genomic region among 510 E. coli strains from animals and humans; (ii) delineate associations between the polymorphism of this region and features such as phylogenetic background of E. coli, pathotype, host species, clinical condition, serogroup and virulence associated genes (VAG)s; and (iii) identify the most important VAGs for classification of the o454-nlpD region. Size variation in the o454-nlpD region was investigated by PCR amplification and sequencing. Phylogenetic relationships were assessed by Ecor- and Multilocus sequence- typing (MLST), and a comparative analysis between mutS gene phylogenetic tree obtained with RAxML and the MLST grouping method was performed. Correlation between o454-nlpD patterns and the features described above were analysed. In addition, the importance of 47 PCR-amplified ExPEC-related VAGs for classification of o454-nlpD patterns was investigated by means of Random Forest algorithm. Four main structures (patterns I-IV) of the o454-nlpD region among ExPEC and commensal E. coli strains were identified. Statistical analysis showed a positive and exclusive association between pattern III and the ExPEC strains. A strong association between pattern III and either the Ecor group B2 or the sequence type complexes known to represent the phylogenetic background of highly virulent ExPEC strains (such as STC95, STC73 and STC131) was found as well. RF analyses determined five genes (csgA, malX, chuA, sit, and vat) to be suitable to predict pattern III strains. The significant association between pattern III and group B2 strains suggested the o454-nlpD region to be of great value in identifying

  11. Correlation between the genomic o454-nlpD region polymorphisms, virulence gene equipment and phylogenetic group of extraintestinal Escherichia coli (ExPEC) enables pathotyping irrespective of host, disease and source of isolation

    PubMed Central

    2014-01-01

    Background The mutS-rpoS intergenic region in E. coli displays a mosaic structure which revealed pathotype specific patterns. To assess the importance of this region as a surrogate marker for the identification of highly virulent extraintestinal pathogenic E. coli (ExPEC) strains we aimed to: (i) characterize the genetic diversity of the mutS gene and the o454-nlpD genomic region among 510 E. coli strains from animals and humans; (ii) delineate associations between the polymorphism of this region and features such as phylogenetic background of E. coli, pathotype, host species, clinical condition, serogroup and virulence associated genes (VAG)s; and (iii) identify the most important VAGs for classification of the o454-nlpD region. Methods Size variation in the o454-nlpD region was investigated by PCR amplification and sequencing. Phylogenetic relationships were assessed by Ecor- and Multilocus sequence- typing (MLST), and a comparative analysis between mutS gene phylogenetic tree obtained with RAxML and the MLST grouping method was performed. Correlation between o454-nlpD patterns and the features described above were analysed. In addition, the importance of 47 PCR-amplified ExPEC-related VAGs for classification of o454-nlpD patterns was investigated by means of Random Forest algorithm. Results Four main structures (patterns I-IV) of the o454-nlpD region among ExPEC and commensal E. coli strains were identified. Statistical analysis showed a positive and exclusive association between pattern III and the ExPEC strains. A strong association between pattern III and either the Ecor group B2 or the sequence type complexes known to represent the phylogenetic background of highly virulent ExPEC strains (such as STC95, STC73 and STC131) was found as well. RF analyses determined five genes (csgA, malX, chuA, sit, and vat) to be suitable to predict pattern III strains. Conclusion The significant association between pattern III and group B2 strains suggested the o454-nlp

  12. Uropathogenic Escherichia coli pathogenicity islands and other ExPEC virulence genes may contribute to the genome variability of enteroinvasive E. coli.

    PubMed

    da Silva, Laís Cristina; de Mello Santos, Ana Carolina; Silva, Rosa Maria

    2017-03-16

    Enteroinvasive Escherichia coli (EIEC) may be the causative agent of part of those million cases of diarrhea illness reported worldwide every year and attributable to Shigella. That is because both enteropathogens have many common characteristics that difficult their identification either by traditional microbiological methods or by molecular tools used in the clinical laboratory settings. While Shigella has been extensively studied, EIEC remains barely characterized at the molecular level. Recent EIEC important outbreaks, apparently generating more life-threatening cases, have prompted us to screen EIEC for virulence traits usually related to extraintestinal pathogenic E. coli (ExPEC). That could explain the appearance of EIEC strains presenting higher virulence potential. EIEC strains were distributed mainly in three phylogroups in a serogroup-dependent manner. Serogroups O124, O136, O144, and O152 were exclusively classified in phylogroup A; O143 in group E; and O28ac and O29 in group B1. Only two serogroups showed diverse phylogenetic origin as follows: O164 was assigned to groups A, B1, C, and B2 (one strain each), and O167 in groups E (five strains), and A (one strain) (Table 1). Eleven of 20 virulence genes (VGs) searched were detected, and the majority of the 19 different VGs combinations found were serogroup-specific. Uropathogenic E. coli (UPEC) PAI genetic markers were detected in all EIEC strains. PAIs IJ96 and IICFT073 were the most frequent (92.1 and 80.4%, respectively). PAI IV536 was restricted to some serogroups from phylogroups A, B1 and E. PAI ICFT073 was uniquely detected in phylogroups B2 and E. A total of 45 (88%) strains presented multiple PAI markers (two to four). PAIs IJ96 and IICFT073 were found together in 80% of strains. EIEC is a DEC pathovar that presents VGs and pathogenicity island genetic markers typically associated with ExPEC, especially UPEC. These features are distributed in a phylogenetic and serogroup-dependent manner

  13. Expanding our understanding of sequence-function relationships of type II polyketide biosynthetic gene clusters: bioinformatics-guided identification of Frankiamicin A from Frankia sp. EAN1pec.

    PubMed

    Ogasawara, Yasushi; Yackley, Benjamin J; Greenberg, Jacob A; Rogelj, Snezna; Melançon, Charles E

    2015-01-01

    A large and rapidly increasing number of unstudied "orphan" natural product biosynthetic gene clusters are being uncovered in sequenced microbial genomes. An important goal of modern natural products research is to be able to accurately predict natural product structures and biosynthetic pathways from these gene cluster sequences. This requires both development of bioinformatic methods for global analysis of these gene clusters and experimental characterization of select products produced by gene clusters with divergent sequence characteristics. Here, we conduct global bioinformatic analysis of all available type II polyketide gene cluster sequences and identify a conserved set of gene clusters with unique ketosynthase α/β sequence characteristics in the genomes of Frankia species, a group of Actinobacteria with underexploited natural product biosynthetic potential. Through LC-MS profiling of extracts from several Frankia species grown under various conditions, we identified Frankia sp. EAN1pec as producing a compound with spectral characteristics consistent with the type II polyketide produced by this gene cluster. We isolated the compound, a pentangular polyketide which we named frankiamicin A, and elucidated its structure by NMR and labeled precursor feeding. We also propose biosynthetic and regulatory pathways for frankiamicin A based on comparative genomic analysis and literature precedent, and conduct bioactivity assays of the compound. Our findings provide new information linking this set of Frankia gene clusters with the compound they produce, and our approach has implications for accurate functional prediction of the many other type II polyketide clusters present in bacterial genomes.

  14. Presence of pathogenicity islands and virulence genes of extraintestinal pathogenic Escherichia coli (ExPEC) in isolates from avian organic fertilizer.

    PubMed

    Gazal, Luís Eduardo S; Puño-Sarmiento, Juan J; Medeiros, Leonardo P; Cyoia, Paula S; da Silveira, Wanderlei D; Kobayashi, Renata K T; Nakazato, Gerson

    2015-12-01

    Poultry litter is commonly used as fertilizer in agriculture. However, this poultry litter must be processed prior to use, since poultry have a large number of pathogenic microorganisms. The aims of this study were to isolate and genotypically and phenotypically characterize Escherichia coli from avian organic fertilizer. Sixty-four E. coli isolates were identified from avian organic fertilizer and characterized for ExPEC virulence factors, pathogenicity islands, phylogenetic groups, antimicrobial resistance, biofilm formation, and adhesion to HEp-2 cells. Sixty-three isolates (98.4%) showed at least one virulence gene (fimH, ecpA, sitA, traT, iutA, iroN, hlyF, ompT and iss). The predominant phylogenetic groups were groups A (59.3%) and B1 (34.3%). The pathogenicity island CFT073II (51.5%) was the most prevalent among the isolates tested. Thirty-two isolates (50%) were resistant to at least one antimicrobial agent. Approximately 90% of isolates adhered to HEp-2 cells, and the predominant pattern was aggregative adherence (74.1%). In the biofilm assay, it was observed that 75% of isolates did not produce biofilm. These results lead us to conclude that some E. coli isolates from avian organic fertilizer could be pathogenic for humans.

  15. Comparative Analysis of Phylogenetic Assignment of Human and Avian ExPEC and Fecal Commensal Escherichia coli Using the (Previous and Revised) Clermont Phylogenetic Typing Methods and its Impact on Avian Pathogenic Escherichia coli (APEC) Classification.

    PubMed

    Logue, Catherine M; Wannemuehler, Yvonne; Nicholson, Bryon A; Doetkott, Curt; Barbieri, Nicolle L; Nolan, Lisa K

    2017-01-01

    The Clermont scheme has been used for subtyping of Escherichia coli since it was initially described in early 2000. Since then, researchers have used the scheme to type and sub-type commensal E. coli and pathogenic E. coli, such as extraintestinal pathogenic E. coli (ExPEC), and compare their phylogenetic assignment by pathogenicity, serogroup, distribution among ExPEC of different host species and complement of virulence and resistance traits. Here, we compare assignments of human and avian ExPEC and commensal E. coli using the old and revised Clermont schemes to determine if the new scheme provides a refined snapshot of isolate classification. 1,996 E. coli from human hosts and poultry, including 84 human neonatal meningitis E. coli isolates, 88 human vaginal E. coli, 696 human uropathogenic E. coli, 197 healthy human fecal E. coli, 452 avian pathogenic E. coli (APEC), 200 retail poultry E. coli, 80 crop and gizzard E. coli from healthy poultry at slaughter and 199 fecal E. coli from healthy birds at slaughter. All isolates were subject to phylogenetic analysis using the Clermont et al. (2000, 2013) schemes and compared to determine the effect of the new classification on strain designation. Most of the isolates' strain designation remained where they were originally assigned. Greatest designation change occurred in APEC where 53.8% of isolates were reclassified; while classification rates among human strains ranged from 8 to 14%. However, some significant changes were observed for UPEC associated strains with significant (P < 0.05) designation changes observed from A to C and D to E or F phylogenetic types; a similar designation change was noted among NMEC for D to F designation change. Among the APEC significant designation changes were observed from A to C and D to E and F. These studies suggest that the new scheme provides a tighter and more meaningful definition of some ExPEC; while the new typing scheme has a significant impact on APEC classification. A

  16. Comparative Analysis of Phylogenetic Assignment of Human and Avian ExPEC and Fecal Commensal Escherichia coli Using the (Previous and Revised) Clermont Phylogenetic Typing Methods and its Impact on Avian Pathogenic Escherichia coli (APEC) Classification

    PubMed Central

    Logue, Catherine M.; Wannemuehler, Yvonne; Nicholson, Bryon A.; Doetkott, Curt; Barbieri, Nicolle L.; Nolan, Lisa K.

    2017-01-01

    The Clermont scheme has been used for subtyping of Escherichia coli since it was initially described in early 2000. Since then, researchers have used the scheme to type and sub-type commensal E. coli and pathogenic E. coli, such as extraintestinal pathogenic E. coli (ExPEC), and compare their phylogenetic assignment by pathogenicity, serogroup, distribution among ExPEC of different host species and complement of virulence and resistance traits. Here, we compare assignments of human and avian ExPEC and commensal E. coli using the old and revised Clermont schemes to determine if the new scheme provides a refined snapshot of isolate classification. 1,996 E. coli from human hosts and poultry, including 84 human neonatal meningitis E. coli isolates, 88 human vaginal E. coli, 696 human uropathogenic E. coli, 197 healthy human fecal E. coli, 452 avian pathogenic E. coli (APEC), 200 retail poultry E. coli, 80 crop and gizzard E. coli from healthy poultry at slaughter and 199 fecal E. coli from healthy birds at slaughter. All isolates were subject to phylogenetic analysis using the Clermont et al. (2000, 2013) schemes and compared to determine the effect of the new classification on strain designation. Most of the isolates’ strain designation remained where they were originally assigned. Greatest designation change occurred in APEC where 53.8% of isolates were reclassified; while classification rates among human strains ranged from 8 to 14%. However, some significant changes were observed for UPEC associated strains with significant (P < 0.05) designation changes observed from A to C and D to E or F phylogenetic types; a similar designation change was noted among NMEC for D to F designation change. Among the APEC significant designation changes were observed from A to C and D to E and F. These studies suggest that the new scheme provides a tighter and more meaningful definition of some ExPEC; while the new typing scheme has a significant impact on APEC classification. A

  17. The Complete Sequence and Comparative Analysis of a Multidrug-Resistance and Virulence Multireplicon IncFII Plasmid pEC302/04 from an Extraintestinal Pathogenic Escherichia coli EC302/04 Indicate Extensive Diversity of IncFII Plasmids

    PubMed Central

    Ho, Wing Sze; Yap, Kien-Pong; Yeo, Chew Chieng; Rajasekaram, Ganeswrie; Thong, Kwai Lin

    2016-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) that causes extraintestinal infections often harbor plasmids encoding fitness traits such as resistance and virulence determinants that are of clinical importance. We determined the complete nucleotide sequence of plasmid pEC302/04 from a multidrug-resistant E. coli EC302/04 which was isolated from the tracheal aspirate of a patient in Malaysia. In addition, we also performed comparative sequence analyses of 18 related IncFIIA plasmids to determine the phylogenetic relationship and diversity of these plasmids. The 140,232 bp pEC302/04 is a multireplicon plasmid that bears three replication systems (FII, FIA, and FIB) with subtype of F2:A1:B1. The plasmid is self-transmissible with a complete transfer region. pEC302/04 also carries antibiotic resistance genes such as blaTEM−1 and a class I integron containing sul1, cml and aadA resistance genes, conferring multidrug resistance (MDR) to its host, E. coli EC302/04. Besides, two iron acquisition systems (SitABCD and IutA-IucABCD) which are the conserved virulence determinants of ExPEC-colicin V or B and M (ColV/ColBM)-producing plasmids were identified in pEC302/04. Multiple toxin-antitoxin (TA)-based addiction systems (i.e., PemI/PemK, VagC/VagD, CcdA/CcdB, and Hok/Sok) and a plasmid partitioning system, ParAB, and PsiAB, which are important for plasmid maintenance were also found. Comparative plasmid analysis revealed only one conserved gene, the repA1 as the core genome, showing that there is an extensive diversity among the IncFIIA plasmids. The phylogenetic relationship of 18 IncF plasmids based on the core regions revealed that ColV/ColBM-plasmids and non-ColV/ColBM plasmids were separated into two distinct groups. These plasmids, which carry highly diverse genetic contents, are also mosaic in nature. The atypical combination of genetic materials, i.e., the MDR- and ColV/ColBM-plasmid-virulence encoding regions in a single ExPEC plasmid is rare but of clinical

  18. Comparative Genomic Analysis Shows That Avian Pathogenic Escherichia coli Isolate IMT5155 (O2:K1:H5; ST Complex 95, ST140) Shares Close Relationship with ST95 APEC O1:K1 and Human ExPEC O18:K1 Strains

    PubMed Central

    Pan, Zihao; Hu, Lin; Wang, Shaohui; Wang, Haojin; Leung, Frederick C.; Dai, Jianjun; Fan, Hongjie

    2014-01-01

    Avian pathogenic E. coli and human extraintestinal pathogenic E. coli serotypes O1, O2 and O18 strains isolated from different hosts are generally located in phylogroup B2 and ST complex 95, and they share similar genetic characteristics and pathogenicity, with no or minimal host specificity. They are popular objects for the study of ExPEC genetic characteristics and pathogenesis in recent years. Here, we investigated the evolution and genetic blueprint of APEC pathotype by performing phylogenetic and comparative genome analysis of avian pathogenic E. coli strain IMT5155 (O2:K1:H5; ST complex 95, ST140) with other E. coli pathotypes. Phylogeny analyses indicated that IMT5155 has closest evolutionary relationship with APEC O1, IHE3034, and UTI89. Comparative genomic analysis showed that IMT5155 and APEC O1 shared significant genetic overlap/similarities with human ExPEC dominant O18:K1 strains (IHE3034 and UTI89). Furthermore, the unique PAI I5155 (GI-12) was identified and found to be conserved in APEC O2 serotype isolates. GI-7 and GI-16 encoding two typical T6SSs in IMT5155 might be useful markers for the identification of ExPEC dominant serotypes (O1, O2, and O18) strains. IMT5155 contained a ColV plasmid p1ColV5155, which defined the APEC pathotype. The distribution analysis of 10 sequenced ExPEC pan-genome virulence factors among 47 sequenced E. coli strains provided meaningful information for B2 APEC/ExPEC-specific virulence factors, including several adhesins, invasins, toxins, iron acquisition systems, and so on. The pathogenicity tests of IMT5155 and other APEC O1:K1 and O2:K1 serotypes strains (isolated in China) through four animal models showed that they were highly virulent for avian colisepticemia and able to cause septicemia and meningitis in neonatal rats, suggesting zoonotic potential of these APEC O1:K1 and O2:K1 isolates. PMID:25397580

  19. NEW TECHNOLOGY AND PEC PROCESS - COLUMBUS, GA

    EPA Science Inventory

    The presentation will discuss Columbus, Georgia’s Biosolids Flow-through Thermophilic Treatment (BFT3) Process. Site-specific equivalency requires proof. Laboratory-scale pathogen testing must exceed Class A performance criteria while simulating full scale as closely as pos...

  20. Complete Sequence of pEC012, a Multidrug-Resistant IncI1 ST71 Plasmid Carrying bla CTX-M-65, rmtB, fosA3, floR, and oqxAB in an Avian Escherichia coli ST117 Strain.

    PubMed

    Pan, Yu-Shan; Zong, Zhi-Yong; Yuan, Li; Du, Xiang-Dang; Huang, Hui; Zhong, Xing-Hao; Hu, Gong-Zheng

    2016-01-01

    A 139,622-bp IncI1 ST71 conjugative plasmid pEC012 from an avian Escherichia coli D-ST117 strain was sequenced, which carried five IS26-bracketed resistance modules: IS26-fosA3-orf1-orf2-Δorf3-IS26, IS26-fip-ΔISEcp1-bla CTX-M-65-IS903D-iroN-IS26, IS26-ΔtnpR-bla TEM-1-rmtB-IS26, IS26-oqxAB-IS26, and IS26-floR-aac(3)-IV-IS26. The backbone of pEC012 was similar to that of several other IncI1 ST71 plasmids: pV408, pM105, and pC271, but these plasmids had different arrangements of multidrug resistance region. In addition, the novel ISEc57 element was identified, which is in the IS21 family. The stepwise emergence of multi-resistance regions demonstrated the accumulation of different resistance determinants through homologous recombination. To the best of our knowledge, this is the first study to identify a multidrug-resistant IncI1 ST71 plasmid carrying bla CTX-M-65, rmtB, fosA3, floR, and oqxAB in an avian E. coli ST117 strain.

  1. Complete Sequence of pEC012, a Multidrug-Resistant IncI1 ST71 Plasmid Carrying blaCTX-M-65, rmtB, fosA3, floR, and oqxAB in an Avian Escherichia coli ST117 Strain

    PubMed Central

    Pan, Yu-Shan; Zong, Zhi-Yong; Yuan, Li; Du, Xiang-Dang; Huang, Hui; Zhong, Xing-Hao; Hu, Gong-Zheng

    2016-01-01

    A 139,622-bp IncI1 ST71 conjugative plasmid pEC012 from an avian Escherichia coli D-ST117 strain was sequenced, which carried five IS26-bracketed resistance modules: IS26-fosA3-orf1-orf2-Δorf3-IS26, IS26-fip-ΔISEcp1-blaCTX-M-65-IS903D-iroN-IS26, IS26-ΔtnpR-blaTEM-1-rmtB-IS26, IS26-oqxAB-IS26, and IS26-floR-aac(3)-IV-IS26. The backbone of pEC012 was similar to that of several other IncI1 ST71 plasmids: pV408, pM105, and pC271, but these plasmids had different arrangements of multidrug resistance region. In addition, the novel ISEc57 element was identified, which is in the IS21 family. The stepwise emergence of multi-resistance regions demonstrated the accumulation of different resistance determinants through homologous recombination. To the best of our knowledge, this is the first study to identify a multidrug-resistant IncI1 ST71 plasmid carrying blaCTX-M-65, rmtB, fosA3, floR, and oqxAB in an avian E. coli ST117 strain. PMID:27486449

  2. Electromagnetic propagation in PEC and absorbing curved S-ducts

    NASA Technical Reports Server (NTRS)

    Baumeister, Kenneth J.

    1988-01-01

    A finite-element Galerkin formulation has been developed to study transverse magnetic (TM) wave propagation in 2-D S-curved ducts with both perfectly conducting and absorbing walls. The reflection and transmission at the entrances and the exits of the curved ducts are determined by coupling the finite-element solutions in the curved ducts to the eigenfunctions of an infinite, uniform, perfectly conducting duct. Example solutions are presented for a double mitred and S-ducts of various lengths. The length of the S-duct is found to significantly effect the reflective characteristics of the duct. Also, the effect of curvature on an absorbing duct is illustrated.

  3. IUE observations of RW Hydrae /gM2 + pec/

    NASA Technical Reports Server (NTRS)

    Kafatos, M.; Michalitsianos, A. G.; Hobbs, R. W.

    1980-01-01

    Analysis of the intense UV continuum observed between 1100 and 2000 A suggested that observations of the late type star RW Hya is a binary system in which the secondary is the central star of a planetary nebula. The UV spectrum is characterized by semiforbidden and allowed transition lines, of which the C IV doublet is particularly strong. Tidal interaction from the M giant is proposed as a method of forming a nebula with the characteristic densities inferred from the UV line analysis. RW Hya is suggested as a possible source of soft X-ray emission if material is accreting onto the surface of the secondary.

  4. Four Papers of the Pecs Conference on Contrastive Linguistics (Pecs, 14-16 October 1971). The Hungarian-English Contrastive Linguistics Project, Working Papers No. 4.

    ERIC Educational Resources Information Center

    Dezso, Laszlo, Ed.; Nemser, William, Ed.

    The following conference papers are included here: (1) "Language Typology and Contrastive Linguistics," by Laszlo Dezso and William Nemser, summarizes the history of typology and discusses the application of typology to research on language acquisition. (2) "Contrastive Aspects of British and American English with Implications for…

  5. Flexing the PECs: Predicting environmental concentrations of veterinary drugs in Canadian agricultural soils.

    PubMed

    Kullik, Sigrun A; Belknap, Andrew M

    2017-03-01

    Veterinary drugs administered to food animals primarily enter ecosystems through the application of livestock waste to agricultural land. Although veterinary drugs are essential for protecting animal health, their entry into the environment may pose a risk for nontarget organisms. A means to predict environmental concentrations of new veterinary drug ingredients in soil is required to assess their environmental fate, distribution, and potential effects. The Canadian predicted environmental concentrations in soil (PECsoil) for new veterinary drug ingredients for use in intensively reared animals is based on the approach currently used by the European Medicines Agency for VICH Phase I environmental assessments. The calculation for the European Medicines Agency PECsoil can be adapted to account for regional animal husbandry and land use practices. Canadian agricultural practices for intensively reared cattle, pigs, and poultry differ substantially from those in the European Union. The development of PECsoil default values and livestock categories representative of typical Canadian animal production methods and nutrient management practices culminates several years of research and an extensive survey and analysis of the scientific literature, Canadian agricultural statistics, national and provincial management recommendations, veterinary product databases, and producers. A PECsoil can be used to rapidly identify new veterinary drugs intended for intensive livestock production that should undergo targeted ecotoxicity and fate testing. The Canadian PECsoil model is readily available, transparent, and requires minimal inputs to generate a screening level environmental assessment for veterinary drugs that can be refined if additional data are available. PECsoil values for a hypothetical veterinary drug dosage regimen are presented and discussed in an international context. Integr Environ Assess Manag 2017;13:331-341. © 2016 Her Majesty the Queen in Right of Canada. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of SETAC. Reproduced with the permission of the Minister of Health.

  6. Tuning the composition of Bi x W y O nanorods towards zero bias PEC water splitting

    NASA Astrophysics Data System (ADS)

    Larson, Steven; Zhao, Yiping

    2016-06-01

    A unique co-oblique angle deposition method was used to create nanorod arrays of mixed phase Bi2O3/WO3/Bi2WO6 with varying atomic ratios of Bi to W. The effect of the tuning on the resulting nanostructures was characterized by EDX, SEM, XRD, optical transmission, specular reflection, and diffuse reflection spectroscopy. Samples with different Bi:W atomic ratio had a wide range of morphology and composition due to the surface mobility of deposited bismuth and its volume expansion during oxidation. Their photocatalytic and photoelectrochemical properties were investigated by methylene blue degradation and photo-generated current respectively. The sample with 38 at.% Bi showed the highest photodecay rates as well as the maximum photocurrent density, 4.3 μA cm-2, at a bias potential of 600 mV versus Ag/AgCl (3M KCl); while the sample with 50 at.% Bi exhibited a high photocurrent density of 0.35 μA cm-2 at zero bias potential, which indicates that varying the composition and mixed crystal phases of different oxides with appropriate band gaps and locations could hold the key to a visible light driven, zero bias potential, photoelectrochemical cell.

  7. Impact of PECS tablet computer app on receptive identification of pictures given a verbal stimulus.

    PubMed

    Ganz, Jennifer B; Hong, Ee Rea; Goodwyn, Fara; Kite, Elizabeth; Gilliland, Whitney

    2015-04-01

    The purpose of this brief report was to determine the effect on receptive identification of photos of a tablet computer-based augmentative and alternative communication (AAC) system with voice output. A multiple baseline single-case experimental design across vocabulary words was implemented. One participant, a preschool-aged boy with autism and little intelligible verbal language, was included in the study. Although a functional relation between the intervention and the dependent variable was not established, the intervention did appear to result in mild improvement for two of the three vocabulary words selected. The authors recommend further investigations of the collateral impacts of AAC on skills other than expressive language.

  8. View of MISSE PEC taken during a session of Expedition 15 EVA

    NASA Image and Video Library

    2007-07-23

    ISS015-E-19036 (23 July 2007) --- The shadow of astronaut Clay Anderson, Expedition 15 flight engineer, who is anchored to the Canadarm2 foot restraint, is visible against solar array panels of a Soyuz spacecraft docked to the International Space Station during a session of extravehicular activity (EVA). This image was captured following the jettisoning of an Early Ammonia Servicer (EAS).

  9. Picture Exchange Communication System (PECS) or Sign Language: An Evidence-Based Decision-Making Example

    ERIC Educational Resources Information Center

    Spencer, Trina D.; Petersen, Douglas B.; Gillam, Sandra L.

    2008-01-01

    Evidence-based practice (EBP) refers to clinical decisions as a result of the careful integration of research evidence and student needs. Legal mandates such as No Child Left Behind require teachers to employ evidence-based practices in their classrooms, yet teachers receive little guidance regarding how to determine which practices are…

  10. Picture Exchange Communication System (PECS) or Sign Language: An Evidence-Based Decision-Making Example

    ERIC Educational Resources Information Center

    Spencer, Trina D.; Petersen, Douglas B.; Gillam, Sandra L.

    2008-01-01

    Evidence-based practice (EBP) refers to clinical decisions as a result of the careful integration of research evidence and student needs. Legal mandates such as No Child Left Behind require teachers to employ evidence-based practices in their classrooms, yet teachers receive little guidance regarding how to determine which practices are…

  11. A Picture's Worth: PECS and Other Visual Communication Strategies in Autism. Topics in Autism.

    ERIC Educational Resources Information Center

    Bondy, Andy; Frost, Lori

    This book is intended to help parents and professionals understand the communication difficulties of children and adults who do not speak, including those with autism spectrum disorders. The first four chapters describe typical characteristics of nonverbal individuals and offer examples of the authors' approach to communication and the…

  12. From Premack to PECS: 25 Years of Progress in Communication Intervention for Individuals with Developmental Disabilities

    ERIC Educational Resources Information Center

    Sigafoos, Jeff

    2005-01-01

    Educational and behavioural psychologists have made major contributions to the field of communication intervention for individuals with developmental and physical disabilities. A brief personal perspective is provided on some of the major works and contributors that have shaped the field over the past 25 years. Major contributions and personal…

  13. Update on PEC Activities and Introduction of Website and Improved Application Process

    EPA Science Inventory

    Over the last several years, there has been a growing interest in using alternative technologies for disinfection of municipal sludge destined for land application. The 503 regulations include provisions for permitting the use of alternative and innovative treatment technologies....

  14. From Premack to PECS: 25 Years of Progress in Communication Intervention for Individuals with Developmental Disabilities

    ERIC Educational Resources Information Center

    Sigafoos, Jeff

    2005-01-01

    Educational and behavioural psychologists have made major contributions to the field of communication intervention for individuals with developmental and physical disabilities. A brief personal perspective is provided on some of the major works and contributors that have shaped the field over the past 25 years. Major contributions and personal…

  15. Expectant management compared with physical examination-indicated cerclage (EM-PEC) in selected women with a dilated cervix at 14(0/7)-25(6/7) weeks: results from the EM-PEC international cohort study.

    PubMed

    Pereira, Leonardo; Cotter, Amanda; Gómez, Ricardo; Berghella, Vincenzo; Prasertcharoensuk, Witoon; Rasanen, Juha; Chaithongwongwatthana, Surasith; Mittal, Suneeta; Daly, Sean; Airoldi, Jim; Tolosa, Jorge E

    2007-11-01

    The objective of the study was to compare pregnancy outcomes in selected women with a dilated cervix who underwent expectant management or physical examination-indicated cerclage. This was a historical cohort study conducted by the Global Network for Perinatal and Reproductive Health. Women between 14(0/7) and 25(6/7) weeks' gestation with a dilated cervix were identified at 10 centers by ultrasound or digital examination. Primary outcome was time from presentation until delivery (weeks). Secondary outcomes were neonatal survival, birthweight greater than 1500 g and preterm birth less than 28 weeks. Multivariate regression was used to assess the likelihood of neonatal outcomes and control for confounders. Of 225 women, 152 received a physical examination-indicated cerclage, and 73 were managed expectantly without cerclage. Cervical dilation, gestational age at presentation, and antenatal steroid use differed between groups. In the adjusted analyses, cerclage was associated with longer interval from presentation until delivery, improved neonatal survival, birthweight greater than 1500 g and preterm birth less than 28 weeks, compared with expectant management. Similar results were obtained in the analyses limited to women dilated between 2 and 4 cm (n = 122). In this study, the largest cohort reported to date, physical examination-indicated cerclage appears to prolong gestation and improve neonatal survival, compared with expectant management in selected women with cervical dilation between 14(0/7) and 25(6/7) weeks. A randomized, controlled trial should be conducted to determine whether these potential benefits outweigh the risks of cerclage placement in this population.

  16. A practical, evidence-based, comprehensive (PEC) physical examination for diagnosing pathology of the long head of the biceps.

    PubMed

    Rosas, Samuel; Krill, Michael K; Amoo-Achampong, Kelms; Kwon, KiHyun; Nwachukwu, Benedict U; McCormick, Frank

    2017-08-01

    Clinical examination of the shoulder joint has gained attention as clinicians aim to use an evidence-based examination of the biceps tendon, with the desire for a proper diagnosis while minimizing costly imaging procedures. The purpose of this study is to create a decision tree analysis that enables the development of a clinical algorithm for diagnosing long head of biceps (LHB) pathology. A literature review of Level I and II diagnostic studies was conducted to extract characteristics of clinical tests for LHB pathology through a systematic review of PubMed, Medline, Ovid, and Cochrane Review databases. Tests were combined in series and parallel to determine sensitivities and specificities, and positive and negative likelihood ratios were determined for each combination using a subjective pretest probability. The "gold standard" for diagnosis in all included studies was arthroscopy or arthrotomy. The optimal testing modality was use of the uppercut test combined with the tenderness to palpation of the biceps tendon test. This combination achieved a sensitivity of 88.4% when performed in parallel and a specificity of 93.8% when performed in series. These tests used in combination optimize post-test probability accuracy greater than any single individual test. Performing the uppercut test and biceps groove tenderness to palpation test together has the highest sensitivity and specificity of known physical examinations maneuvers to aid in the diagnosis of LHB pathology compared with diagnostic arthroscopy (practical, evidence-based, comprehensive examination). A decision tree analysis aides in the practical, evidence-based, comprehensive examination diagnostic accuracy post-testing based on the ordinal scale pretest probability. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  17. The Picture Exchange Communication System (PECS): A Promising Method for Improving Communication Skills of Learners with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Ganz, Jennifer B.; Simpson, Richard L.; Lund, Emily M.

    2012-01-01

    Children and youth with autism spectrum disorders (ASD) and other developmental delays frequently experience deficits in functional communication. Identifying and using suitable communication enhancement and augmentative and alternative communication supports is essential to achievement of positive outcomes for these learners. This article…

  18. Scattering by a zero-thickness PEC disk: A new analytically regularizing procedure based on Helmholtz decomposition and Galerkin method

    NASA Astrophysics Data System (ADS)

    Lucido, Mario; Panariello, Gaetano; Schettino, Fulvio

    2017-01-01

    The aim of this paper is the introduction of a new analytically regularizing procedure, based on Helmholtz decomposition and Galerkin method, successfully employed to analyze the electromagnetic scattering by zero-thickness perfectly electrically conducting circular disk. After expanding the fields in cylindrical harmonics, the problem is formulated as an electric field integral equation in the vector Hankel transform domain. Assuming as unknowns the surface curl-free and divergence-free contributions of the surface current density, a second-kind Fredholm infinite matrix-operator equation is obtained by means of Galerkin method with expansion functions reconstructing the expected physical behavior of the surface current density and with closed-form spectral domain counterparts, which form a complete set of orthogonal eigenfunctions of the most singular part of the integral operator. The coefficients of the scattering matrix are single improper integrals which can be quickly computed by means of analytical asymptotic acceleration technique. Comparisons with the literature have been provided in order to show the accuracy and efficiency of the presented technique.

  19. The Picture Exchange Communication System (PECS): A Promising Method for Improving Communication Skills of Learners with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Ganz, Jennifer B.; Simpson, Richard L.; Lund, Emily M.

    2012-01-01

    Children and youth with autism spectrum disorders (ASD) and other developmental delays frequently experience deficits in functional communication. Identifying and using suitable communication enhancement and augmentative and alternative communication supports is essential to achievement of positive outcomes for these learners. This article…

  20. IUE observations of two late-type stars Bx Mon (M + pec) and TV Gem (M1 Iab)

    NASA Technical Reports Server (NTRS)

    Michalitsianos, A. G.; Hobbs, R. W.; Kafatos, M.

    1981-01-01

    The IUE observations of two late type stars BX Mon and TV Gem that reveal the emission properties in the ultraviolet of subluminous companions are discussed. Analysis of the continuum emission observed from BX Mon suggests the companion, is a middle A III star. High excitation emission lines observed between 1200 A and 2000 A that generally do not typify emission observed in either late M type variables or A type stars are also detected. It is suggested that these strong high excitation lines arise in a large volume of gas heated by nonradiation processes that could be the result of tidal interaction and mass exchange in the binary system. In contrast to stars such as BX Mon, the luminous M1 supergiant TV Gem shows unexpected intense UV continuum throughout the sensitivity range of IUE. The UV spectrum of TV Gem is characterized by intense continuum with broad absorption features detected in the short wavelength range. The analysis shows that the companion could be a B9 or A1 III-IV star. Alternate suggestions are presented for explaining the UV continuum in terms of an accretion disk in association with TV Gem.

  1. Study of Sommerfeld and Phase-Integral Approaches for Green’s Functions for PEC-terminated Inhomogeneous Media

    DTIC Science & Technology

    2010-01-08

    one-dimensional Green’s functions. These one-dimensional Green’s functions are the solutions to the one-dimensional Sturm- Liouville problems. In Ref...wavenumbers whose explicit relationship to the one-dimensional Green’s functions are defined via the one-dimensional Sturm- Liouville operator equation [35, p

  2. Effects of Zn amount on the properties of Zn-Zu2O composite films grown for PEC photoelectrodes by using electrochemical deposition

    NASA Astrophysics Data System (ADS)

    Kim, Tae Gyoum; Lee, Hu Joong; Ryu, Hyukhyun; Lee, Won-Jae

    2015-10-01

    In this study, Zn-Cu2O composite films were grown on fluorine-doped tin-oxide (FTO) substrates by using the electrochemical deposition method. Various amounts of Zinc (Zn) were added to grow the Zn-Cu2O composite films. We analyzed the morphological, structural, optical energy band gap and photocurrent density properties of the Zn-Cu2O composite films by using various measurements such as field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), UV-visible spectrophotometry and potentiostat/galvanostat measurements, respectively. As a result, the highest photocurrent density value of -4.04 mA/cm2 was obtained for the 30-wt% sample, which had the lowest Cu2O (111)/ ZnO (101) XRD peak intensity ratio. The highest photocurrent density value from the 30-wt% sample was approximately 2.35 times higher than that from the non-composite Cu2O film (0-wt% sample). From this study, we found that adding Zn could improve the photocurrent values of Zn-Cu2O composite films.

  3. The Profile of Emotional Competence (PEC): development and validation of a self-reported measure that fits dimensions of emotional competence theory.

    PubMed

    Brasseur, Sophie; Grégoire, Jacques; Bourdu, Romain; Mikolajczak, Moïra

    2013-01-01

    Emotional Competence (EC), which refers to individual differences in the identification, understanding, expression, regulation and use of one's own emotions and those of others, has been found to be an important predictor of individuals' adaptation to their environment. Higher EC is associated with greater happiness, better mental and physical health, more satisfying social and marital relationships and greater occupational success. While it is well-known that EC (as a whole) predicts a number of important outcomes, it is unclear so far which specific competency(ies) participate(s) in a given outcome. This is because no measure of EC distinctly measures each of the five core emotional competences, separately for one's own and others' emotions. This lack of information is problematic both theoretically (we do not understand the processes at stake) and practically (we cannot develop customized interventions). This paper aims to address this issue. We developed and validated in four steps a complete (albeit short: 50 items) self-reported measure of EC: the Profile of Emotional Competence. Analyses performed on a representative sample of 5676 subjects revealed promising psychometric properties. The internal consistency of scales and subscales alike was satisfying, factorial structure was as expected, and concurrent/discriminant validity was good.

  4. The Profile of Emotional Competence (PEC): Development and Validation of a Self-Reported Measure that Fits Dimensions of Emotional Competence Theory

    PubMed Central

    Brasseur, Sophie; Grégoire, Jacques; Bourdu, Romain; Mikolajczak, Moïra

    2013-01-01

    Emotional Competence (EC), which refers to individual differences in the identification, understanding, expression, regulation and use of one’s own emotions and those of others, has been found to be an important predictor of individuals’ adaptation to their environment. Higher EC is associated with greater happiness, better mental and physical health, more satisfying social and marital relationships and greater occupational success. While it is well-known that EC (as a whole) predicts a number of important outcomes, it is unclear so far which specific competency(ies) participate(s) in a given outcome. This is because no measure of EC distinctly measures each of the five core emotional competences, separately for one’s own and others’ emotions. This lack of information is problematic both theoretically (we do not understand the processes at stake) and practically (we cannot develop customized interventions). This paper aims to address this issue. We developed and validated in four steps a complete (albeit short: 50 items) self-reported measure of EC: the Profile of Emotional Competence. Analyses performed on a representative sample of 5676 subjects revealed promising psychometric properties. The internal consistency of scales and subscales alike was satisfying, factorial structure was as expected, and concurrent/discriminant validity was good. PMID:23671616

  5. Integrated photoelectrochemical cell and system having a liquid electrolyte

    DOEpatents

    Deng, Xunming; Xu, Liwei

    2010-07-06

    An integrated photoelectrochemical (PEC) cell generates hydrogen and oxygen from water while being illuminated with radiation. The PEC cell employs a liquid electrolyte, a multi-junction photovoltaic electrode, and a thin ion-exchange membrane. A PEC system and a method of making such PEC cell and PEC system are also disclosed.

  6. Synthesis and characterization of pectin derivative with antitumor property against Caco-2 colon cancer cells.

    PubMed

    Almeida, Elizângela A M S; Facchi, Suelen P; Martins, Alessandro F; Nocchi, Samara; Schuquel, Ivânia T A; Nakamura, Celso V; Rubira, Adley F; Muniz, Edvani C

    2015-01-22

    New pectin derivative (Pec-MA) was obtained in specific reaction conditions. The presence of maleoyl groups in Pec-MA structure was confirmed by (1)H NMR and FTIR spectroscopy. The substitution degree of Pec-MA (DS=24%) was determined by (1)H NMR. The properties of Pec-MA were investigated through WAXS, TGA/DTG, SEM and zeta potential techniques. The Pec-MA presented amorphous characteristics and higher-thermal stability compared to raw pectin (Pec). In addition, considerable morphological differences between Pec-MA and Pec were observed by SEM. The cytotoxic effect on the Caco-2 cells showed that the Pec-MA significantly inhibited the growth of colon cancer cells whereas the Pec-MA does not show any cytotoxic effect on the VERO healthy cells. This result opens new perspectives for the manufacture of biomaterials based on Pec with anti-tumor properties.

  7. [Haemorrhagic septicaemia in a pig caused by extraintestinal pathogenic Escherichia coli (ExPEC) as a differential diagnosis in classical swine fever--case report and review of the literature].

    PubMed

    Reiner, Gerald; von Berg, Stephan; Hillen, Sonja; Clemens, Nina; Huisinger, Maike; Burkhardt, Eberhard; Weiss, Reinhardt; Reinacher, Manfred

    2010-01-01

    Domestic pig herds in some regions of Germany are permanently threatened by Classical Swine Fever. In the case of suspicion, a series of infectious and non infectious causes has to be excluded. The present paper describes a case of Escherichia coli septicaemia, with clinical and pathological symptoms that could not be differentiated from European or African Swine Fever. The E. coli strain could not be classified by standard serotyping. Virulence factors common for ETEC (enterotoxic E. coli) or EDEC (edema-disease E. coli) were not detected. Instead, we found P-fimbriae and aerobactin, thus characterising this strain as an extraintestinal pathogenic strain. Such strains have sporadicly been reported as the cause of septicaemia in piglets or weaners, but the present case is the first report of an E. coli-associated septicaemia in an adult pig. This case shows that extraintestinal pathogenic E. coli can be the cause of severe septicaemia and haemorrhagia. They thus have to be considered as a further differential diagnosis in swine fever.

  8. Splitting water with semiconducting photoelectrodes Efficiency considerations

    NASA Astrophysics Data System (ADS)

    Weber, M. F.; Dignam, M. J.

    The efficiencies of three types of photoelectrochemical cells (PEC) are examined. A single bandgap photoelectrode with a dark auxiliary electrode (single-photon PEC), a separately illuminated single bandgap photocathode and photoanode (p-n PEC), and a two bandgap photoelectrode with a dark auxiliary electrode (tandem PEC) are studied. The procedures for calculating free energy losses in the cells are described. Upper limit estimates of efficiencies are calculated by analyzing the fill factors, and hydrogen and oxygen overpotentials. The estimated upper limit efficiency for the single-photon PEC is 7 percent, for the p-n PEC it is 10 percent, and for the tandem PEC it equals 18 percent. It is observed that the single-photon PEC is strongly affected by transport losses and yields the lowest efficiencies, and the tandem PEC is not influenced by transport losses and has the highest efficiencies. The impedance matching problem in the PECs is investigated.

  9. Imaging and Chemotherapeutic Comparisons of Iron Oxide Nanoparticles Chemically and Physically Coated with Poly(ethylene glycol)-b-Poly(ε-caprolactone)-g-Poly(acrylic acid).

    PubMed

    Chen, Guo-Jing; Hsu, Chin; Ke, Jyun-Han; Wang, Li-Fang

    2015-06-01

    We designed a new copolymer, poly(ethylene glycol)-block-poly(ε-caprolactone)-graft-poly(acrylic acid) (PAA-PEC), which could be chemically and physically coated onto iron oxide (Fe3O4) nanoparticles for theranostic applications. The chemically PAA-PEC-coated Fe3O4 nanoparticles (PAA-PEC-IO) were prepared using the carboxylic groups of PAA-PEC to bind the Fe3O4 nanoparticles during a co-precipitation reaction. Because of the amphiphilic properties of PAA-PEC, the compound self-assembled into a core-shell structure. The hydrophobic oleic acid-coated Fe3O4 nanoparticles could then be physically encapsulated inside the hydrophobic core of PAA-PEC (PAA-PEC-OA-IO) using an emulsion technique. A similar amount of iron content was controlled in both the PAA-PEC-IO and PAA-PEC-OA-IO (-23%). The particle diameters, morphologies, superparamagnetism, drug loading efficiency, and transversal relaxivity (r2) were studied and compared between the two magnetic nanoparticles. All results displayed the chemically-synthesized PAA-PEC-IO nanoparticles had higher potential than did the physically-synthesized PAA-PEC-OA-IO as an MRI contrast agent and a drug delivery carrier. Rodamine123-linked PAA-PEC-IO (PAA-PEC-IO-Rh123) was used as a molecular probe. Flow cytometric diagrams indicated that cellular internalization of PAA-PEC-IO occurred primarily through clathrin-mediated endocytosis.

  10. Transcriptional Landscape of Glomerular Parietal Epithelial Cells

    PubMed Central

    Gharib, Sina A.; Pippin, Jeffrey W.; Ohse, Takamoto; Pickering, Scott G.; Krofft, Ronald D.; Shankland, Stuart J.

    2014-01-01

    Very little is known about the function of glomerular parietal epithelial cells (PECs). In this study, we performed genome-wide expression analysis on PEC-enriched capsulated vs. PEC-deprived decapsulated rat glomeruli to determine the transcriptional state of PECs under normal conditions. We identified hundreds of differentially expressed genes that mapped to distinct biologic modules including development, tight junction, ion transport, and metabolic processes. Since developmental programs were highly enriched in PECs, we characterized several of their candidate members at the protein level. Collectively, our findings confirm that PECs are multifaceted cells and help define their diverse functional repertoire. PMID:25127402

  11. [Difference in the Spread of Injectate between Ultrasound Guided Pectoral Nerve Block I and II. A Cadaver Study].

    PubMed

    Kikuchi, Masaru; Takaki, Shunsuke; Nomura, Takeshi; Goto, Takahisa

    2016-03-01

    Pectoral nerve block (PECS block) is first reported by Blanco et al, and mainly used for analgesia for breast surgery in Japan. However, the spread of PECS block is unclear. Ultrasound guided PECS I and II blocks were performed in a cadaver, and the cadaver was dissected for evaluation of the spread of coloring matter. The coloring matter by PECS I block was spread to the axillary region between the major and minor pectoral muscles, while PECS II block remained over the fascia of the serratus muscle from mid-clavicular line to middle axillary line. Two possible routes to the axillary region by PECS I include: dorsal to the pectoral minor muscle through the clavipectoral fascia, and over the pectoral minor muscle to the axillary sheath. Our cadaveric evaluation suggests that PECS I block produces more analgesia of the axillary region than PECS II. Further evaluation is needed in more cadavers.

  12. Saloplastics: processing compact polyelectrolyte complexes.

    PubMed

    Schaaf, Pierre; Schlenoff, Joseph B

    2015-04-17

    Polyelectrolyte complexes (PECs) are prepared by mixing solutions of oppositely charged polyelectrolytes. These diffuse, amorphous precipitates may be compacted into dense materials, CoPECs, by ultracentrifugation (ucPECs) or extrusion (exPECs). The presence of salt water is essential in plasticizing PECs to allow them to be reformed and fused. When hydrated, CoPECs are versatile, rugged, biocompatible, elastic materials with applications including bioinspired materials, supports for enzymes and (nano)composites. In this review, various methods for making CoPECs are described, as well as fundamental responses of CoPEC mechanical properties to salt concentration. Possible applications as synthetic cartilage, enzymatically active biocomposites, self-healing materials, and magnetic nanocomposites are presented.

  13. Enumeration of coliforms and Escherichia coli in frozen black tiger shrimp Penaeus monodon by conventional and rapid methods.

    PubMed

    Suwansonthichai, Sasithorn; Rengpipat, Sirirat

    2003-03-15

    Conventional (most probable number, MPN) and rapid methods-including Chromocult coliform agar (CCA), Fluorocult(R) LMX broth (LMX), and Petrifilm Escherichia coli count plates (PEC) for enumeration of coliforms and E. coli in frozen black tiger shrimp from Thailand were compared in order to assess the possibility of using one of the rapid methods for routine analysis. Enumeration of coliforms and E. coli from 18 samples of regular frozen black tiger shrimp and 156 samples of frozen black tiger shrimp experimentally contaminated with coliforms or E. coli at concentrations of approximately 10, approximately 10(2), and approximately 10(3) CFU g(-1) revealed that at the level of approximately 10 CFU g(-1), coliform numbers ranked as LMX>CCA>MPN=PEC and E. coli as MPN=LMX=PEC=CCA. At the level of approximately 10(2) CFU g(-1), coliform numbers ranked as LMX>MPN=PEC=CCA and E. coli as MPN=LMX>PEC=CCA. At the level of 10(3) CFU g(-1), coliforms ranked as LMX>MPN=CCA>PEC and E. coli as MPN>LMX>CCA>PEC. Agreements with the conventional MPN method for coliforms were LMX 108%, PEC 87.2%, and CCA 91.2% and agreements for E. coli were LMX 101%, PEC 95.7%, and CCA 96.3%. Sensitivities (%) ranked LMX>MPN>CCA=PEC for coliforms and E. coli, whereas equal specificities (100%) of all methods for coliforms and E. coli were demonstrated. Rankings for the other parameters compared were: convenience, PEC>CCA=LMX>MPN; time to detection, MPN>LMX=PEC=CCA; expense, MPN=PEC>CCA>LMX; labor, MPN>LMX=CCA>PEC; accuracy for coliforms, PEC>CCA>MPN>LMX; and accuracy for E. coli, PEC=CCA>LMX>MPN.

  14. AN UPDATE ON TECHNOLOGIES SEEKING PFRP EQUIVALENCY

    EPA Science Inventory

    This presentation will: 1) Review the mandate of the Pathogen Equivalency Committee (PEC), 2) Review the PEC's current membership (of 10), 3) Discuss how a typical application is evaluated, 4) Note where information can be found by those interested in applying to the PEC, 5) List...

  15. Understanding the Picture Exchange Communication System and Its Application in Physical Education

    ERIC Educational Resources Information Center

    Green, Amanda; Sandt, Dawn

    2013-01-01

    This article presents the Picture Exchange Communication System (PECS) and its applications in physical education. The PECS is an appropriate communication intervention for students with autism who lack functional communication skills. It is often confused with other visual support strategies, so the authors delineate the six phases of PECS and…

  16. AN UPDATE ON TECHNOLOGIES SEEKING PFRP EQUIVALENCY

    EPA Science Inventory

    This presentation will: 1) Review the mandate of the Pathogen Equivalency Committee (PEC), 2) Review the PEC's current membership (of 10), 3) Discuss how a typical application is evaluated, 4) Note where information can be found by those interested in applying to the PEC, 5) List...

  17. Biosynthesis of the cyanobacterial light-harvesting polypeptide phycoerythrocyanin holo-alpha subunit in a heterologous host.

    PubMed

    Tooley, Aaron J; Glazer, Alexander N

    2002-09-01

    The entire pathway for the biosynthesis of the phycobiliviolin-bearing His-tagged holo-alpha subunit of the cyanobacterial photosynthetic accessory protein phycoerythrocyanin was reconstituted in Escherichia coli. Cyanobacterial genes encoding enzymes required for the conversion of heme to 3Z-phycocyanobilin, a precursor of phycobiliviolin (namely, heme oxygenase 1 and 3Z-phycocyanobilin:ferredoxin oxidoreductase), were expressed from a plasmid under the control of the hybrid trp-lac (trc) promoter. Genes for the apo-phycoerythrocyanin alpha subunit (pecA) and the heterodimeric lyase/isomerase (pecE and pecF), which catalyzes both the covalent attachment of phycocyanobilin and its concurrent isomerization to phycobiliviolin, were expressed from the trc promoter on a second plasmid. Upon induction, recombinant E. coli used endogenous heme to produce holo-PecA with absorbance and fluorescence properties similar to those of the same protein produced in cyanobacteria. About two-thirds of the apo-PecA was converted to holo-PecA. No significant bilin addition took place in a similarly engineered E. coli strain that lacks pecE and pecF. By using immobilized metal affinity chromatography, both apo-PecA and holo-PecA were isolated as ternary complexes with PecE and PecF. The identities of all three components in the ternary complexes were established unambiguously by protein and tryptic peptide analyses performed by matrix-assisted laser desorption ionization-time of flight mass spectrometry.

  18. Synthesis and properties of isomeric pyridyl-containing chitosan derivatives.

    PubMed

    Bratskaya, S Yu; Azarova, Yu A; Portnyagin, A S; Mechaev, A V; Voit, A V; Pestov, A V

    2013-11-01

    Here we report on the method of synthesis in gel of a new heterocyclic aminopolymer-N-2-(4-pyridyl)ethylchitosan (4-PEC) via direct addition of 4-vinylpyridine to chitosan that yields a derivative with the substitution degree (DS) up to 0.8. The comparison of reactivity, thermal, spectroscopic, and sorption properties of a new derivative and its isomer N-2-(2-pyridyl)ethylchitosan (2-PEC) is presented. 2-PEC has higher sorption capacity and forms more stable chelates with [PdCl4](2-) and [PtCl6](2-) ions than 4-PEC, but the latter shows higher selectivity to noble metals ions in the presence of Cl(-) ions. A gradual increase of the sorption capacities and the affinity coefficient for Cu(2+) and Ni(2+) in the row chitosan<4-PEC<2-PEC was related to the increase of electron donor nitrogen atoms content and chelating properties of 2-PEC. A nearly negligible increase of the 4-PEC sorption capacity for Ag(+), as compared to plain chitosan, was suggested to be dependent on the difference in complexation models for 2-PEC and 4-PEC derivatives. The density functional theory (DFT) calculations have shown that the "pendant" model of the complex with Ag(I) is energetically favorable only for 2-PEC derivative, while in cases of chitosan and 4-PEC only "bridge" complexes can be formed that results in lower sorption capacity.

  19. Understanding the Picture Exchange Communication System and Its Application in Physical Education

    ERIC Educational Resources Information Center

    Green, Amanda; Sandt, Dawn

    2013-01-01

    This article presents the Picture Exchange Communication System (PECS) and its applications in physical education. The PECS is an appropriate communication intervention for students with autism who lack functional communication skills. It is often confused with other visual support strategies, so the authors delineate the six phases of PECS and…

  20. Sulfadiazine—Chitosan Conjugates and Their Polyelectrolyte Complexes with Hyaluronate Destined to the Management of Burn Wounds

    PubMed Central

    Dumitriu, Raluca Petronela; Profire, Lenuta; Nita, Loredana Elena; Dragostin, Oana Maria; Ghetu, Nicolae; Pieptu, Dragoș; Vasile, Cornelia

    2015-01-01

    In the present study polyelectrolyte complexes (PECs) based on new sulfadiazine-chitosan conjugates with sodium hyaluronate have been developed with potential use in treatment of burn wounds. The PECs were chemically characterized using Fourier Transform—Infrared Spectroscopy, Scanning Electon Microscopy and Near Infrared Chemical Imaging Technique. The swelling behavior and in vitro sulfadiazine release were also investigated. The antimicrobial activity was evaluated towards three bacterial strains: Escherichia coli, Listeria monocytogenes and Salmonella thyphymurium. The developed PECs demonstrated their antimicrobial efficiency against tested bacterial strains, the PECs containing sulfadiazine-modified chitosan being more active than PECs containing unmodified chitosan. PMID:28787940

  1. Effects of organoclay to miscibility, mechanical and thermal properties of poly(lactic acid) and propylene-ethylene copolymer blends

    NASA Astrophysics Data System (ADS)

    Wacharawichanant, S.; Ounyai, C.; Rassamee, P.

    2017-07-01

    The effects of propylene-ethylene copolymer (PEC or PEC3300) and clay surface modified with 25-30 wt% of trimethylstearyl ammonium (Clay-TSA) on morphology, thermal and mechanical properties of poly(lactic acid) (PLA) were investigated. The morphology analysis showed PLA/PEC3300 blends clearly demonstrated a two-phase separation of dispersed phase and the matrix phase and the addition of Clay-TSA could improve the miscibility of PLA and PEC3300 blends due to the decreased of the domain sizes of dispersed PEC3300 phase in the polymer matrix. From X-ray diffraction analysis showed the intercalation of PLA chains inside the Clay-TSA and this result implied that Clay-TSA platelets acted as an effective compatibilizer. The tensile properties showed the strain at break of PLA was improved after adding PEC3300 while Young’s modulus, tensile strength and storage modulus decreased. The addition of Clay-TSA could improve Young’s modulus of PLA/PEC3300 blends. The addition of Clay-TSA 7 phr showed the maximum of Young’s modulus of PLA/PEC3300/Clay-TSA composites. The thermal properties found that the addition of PEC3300 and Clay-TSA did not change significantly on the glass transition temperature and melting point temperature of PLA. The percent of crystallinity of PLA decreased with increasing PEC content. The thermal stability of PLA improved after adding PEC3300.

  2. General Characterization Methods for Photoelectrochemical Cells for Solar Water Splitting.

    PubMed

    Shi, Xinjian; Cai, Lili; Ma, Ming; Zheng, Xiaolin; Park, Jong Hyeok

    2015-10-12

    Photoelectrochemical (PEC) water splitting is a very promising technology that converts water into clean hydrogen fuel and oxygen by using solar light. However, the characterization methods for PEC cells are diverse and a systematic introduction to characterization methods for PEC cells has rarely been attempted. Unlike most other review articles that focus mainly on the material used for the working electrodes of PEC cells, this review introduces general characterization methods for PEC cells, including their basic configurations and methods for characterizing their performance under various conditions, regardless of the materials used. Detailed experimental operation procedures with theoretical information are provided for each characterization method. The PEC research area is rapidly expanding and more researchers are beginning to devote themselves to related work. Therefore, the content of this Minireview can provide entry-level knowledge to beginners in the area of PEC, which might accelerate progress in this area. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Escherichia coli and urinary tract infections: the role of poultry-meat.

    PubMed

    Manges, A R

    2016-02-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) is the most common cause of community-acquired and hospital-acquired extraintestinal infections. The hypothesis that human ExPEC may have a food animal reservoir has been a topic of investigation by multiple groups around the world. Experimental studies showing the shared pathogenic potential of human ExPEC and avian pathogenic E. coli suggest that these extraintestinal E. coli may be derived from the same bacterial lineages or share common evolutionary roots. The consistent observation of specific human ExPEC lineages in poultry or poultry products, and rarely in other meat commodities, supports the hypothesis that there may be a poultry reservoir for human ExPEC. The time lag between human ExPEC acquisition (in the intestine) and infection is the fundamental challenge facing studies attempting to attribute ExPEC transmission to poultry or other environmental sources. Even whole genome sequencing efforts to address attribution will struggle with defining meaningful genetic relationships outside of a discrete food-borne outbreak setting. However, if even a fraction of all human ExPEC infections, especially antimicrobial-resistant ExPEC infections, is attributable to the introduction of multidrug-resistant ExPEC lineages through contaminated food product(s), the relevance to public health, food animal production and food safety will be significant. Copyright © 2016 European Society of Clinical Microbiology and Infectious Diseases. Published by Elsevier Ltd. All rights reserved.

  4. Zoonotic potential of Escherichia coli isolates from retail chicken meat products and eggs.

    PubMed

    Mitchell, Natalie M; Johnson, James R; Johnston, Brian; Curtiss, Roy; Mellata, Melha

    2015-02-01

    Chicken products are suspected as a source of extraintestinal pathogenic Escherichia coli (ExPEC), which causes diseases in humans. The zoonotic risk to humans from chicken-source E. coli is not fully elucidated. To clarify the zoonotic risk posed by ExPEC in chicken products and to fill existing knowledge gaps regarding ExPEC zoonosis, we evaluated the prevalence of ExPEC on shell eggs and compared virulence-associated phenotypes between ExPEC and non-ExPEC isolates from both chicken meat and eggs. The prevalence of ExPEC among egg-source isolates was low, i.e., 5/108 (4.7%). Based on combined genotypic and phenotypic screening results, multiple human and avian pathotypes were represented among the chicken-source ExPEC isolates, including avian-pathogenic E. coli (APEC), uropathogenic E. coli (UPEC), neonatal meningitis E. coli (NMEC), and sepsis-associated E. coli (SEPEC), as well as an undefined ExPEC group, which included isolates with fewer virulence factors than the APEC, UPEC, and NMEC isolates. These findings document a substantial prevalence of human-pathogenic ExPEC-associated genes and phenotypes among E. coli isolates from retail chicken products and identify key virulence traits that could be used for screening. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Zoonotic Potential of Escherichia coli Isolates from Retail Chicken Meat Products and Eggs

    PubMed Central

    Mitchell, Natalie M.; Johnson, James R.; Johnston, Brian; Curtiss, Roy

    2014-01-01

    Chicken products are suspected as a source of extraintestinal pathogenic Escherichia coli (ExPEC), which causes diseases in humans. The zoonotic risk to humans from chicken-source E. coli is not fully elucidated. To clarify the zoonotic risk posed by ExPEC in chicken products and to fill existing knowledge gaps regarding ExPEC zoonosis, we evaluated the prevalence of ExPEC on shell eggs and compared virulence-associated phenotypes between ExPEC and non-ExPEC isolates from both chicken meat and eggs. The prevalence of ExPEC among egg-source isolates was low, i.e., 5/108 (4.7%). Based on combined genotypic and phenotypic screening results, multiple human and avian pathotypes were represented among the chicken-source ExPEC isolates, including avian-pathogenic E. coli (APEC), uropathogenic E. coli (UPEC), neonatal meningitis E. coli (NMEC), and sepsis-associated E. coli (SEPEC), as well as an undefined ExPEC group, which included isolates with fewer virulence factors than the APEC, UPEC, and NMEC isolates. These findings document a substantial prevalence of human-pathogenic ExPEC-associated genes and phenotypes among E. coli isolates from retail chicken products and identify key virulence traits that could be used for screening. PMID:25480753

  6. Using jet mixing to prepare polyelectrolyte complexes: complex properties and their interaction with silicon oxide surfaces.

    PubMed

    Ankerfors, Caroline; Ondaral, Sedat; Wågberg, Lars; Odberg, Lars

    2010-11-01

    The influence of mixing procedure on the properties of polyelectrolyte complexes (PECs) was investigated using two complexation techniques, polyelectrolyte titration and jet mixing, the latter being a new method for PEC preparation. For the low-molecular-weight polyelectrolytes polyacrylic acid (PAA) and polyallyl amine hydrochloride (PAH), shorter mixing times produced smaller PECs, whereas for higher molecular weights of the same polyelectrolytes, PEC size first decreased with decreasing mixing time to a certain level, after which it started increasing again. This pattern was likely due to the diffusion-controlled formation of "pre-complexes", which, in the case of low-molecular-weight polymers, occurs sufficiently quickly to form stable complexes; when polyelectrolytes are larger, however, non-equilibrium pre-complexes, more prone to aggregation, are formed. Comparing the techniques revealed that jet mixing produced smaller complexes, allowing PEC size to be controlled by mixing time, which was not the case with polyelectrolyte titration. Higher polyelectrolyte concentration during jet mixing led to the formation of larger PECs. It was also demonstrated that PEC size could be changed after preparation: increasing the pH of the PEC dispersion led to an irreversible increase in PEC size, whereas lowering the pH did not influence PEC size. The adsorption behavior of PECs formed from weak polyelectrolytes on model substrates was studied using QCM-D, SPAR, and AFM imaging; the results indicated that increasing the pH increased the amount of PECs adsorbed to model surfaces. However, the amount of PECs adsorbed to the model surfaces was low compared with other systems in all studied cases. Copyright 2010 Elsevier Inc. All rights reserved.

  7. Linker polypeptides of the phycobilisome from the cyanobacterium Mastigocladus laminosus. I. Isolation and characterization of phycobiliprotein-linker-polypeptide complexes.

    PubMed

    Füglistaller, P; Suter, F; Zuber, H

    1986-07-01

    Phycobilisomes from the cyanobacterium Mastigocladus laminosus cultured in white and red light were isolated and compared with respect to the phycoerythrocyanin (PEC) and linker polypeptide contents. It was verified that the production of PEC is induced by low light intensities. A PEC complex, (alpha PEC beta PEC)6LR34.5,PEC, and a phycocyanin (PC) complex, (alpha PC beta PC)6LR34.5,PC, were isolated from phycobilisomes by Cellex-D anion exchange chromatography and sucrose density gradient centrifugation. The absorption and fluorescence emission maxima of the PEC complex are at 575 and 620 nm and those of the PC complex are at 631 and 647 nm, respectively. The extinction coefficients of the two complexes were determined. From different experiments it was concluded that PEC is present as a hexameric complex, (alpha PEC beta PEC)6LR34.5,PEC, in the phycobilisome. The two linker polypeptides LR34.5,PEC and LR34.5,PC were isolated from their phycobiliprotein complexes by gel filtration on Bio-Gel P-100 in 50% formic acid. A 5-kDa terminal segment of both linker polypeptides was found to influence the hexamer formation of the phycobiliproteins. The same segments have been described to be responsible for the hexamer-hexamer linkage (Yu, M.-H. & Glazer, A.N. (1982) J. Biol. Chem. 257, 3429-3433). A 8.9-kDa linker polypeptide, LR(C)8.9, was isolated from a PEC fraction of the Cellex-D column by Bio-Gel P-100 gel filtration in 50% formic acid. Localisation of this protein within the phycobilisome was attempted. Its most probable function is to terminate the phycobilisomal rods at the end distal to the allophycocyanin core.

  8. Cationic and anionic polyelectrolyte complexes of xylan and chitosan. Interaction with lignocellulosic surfaces.

    PubMed

    Mocchiutti, Paulina; Schnell, Carla N; Rossi, Gerardo D; Peresin, María S; Zanuttini, Miguel A; Galván, María V

    2016-10-05

    Cationic (CatPECs) and anionic (AnPECs) polyelectrolyte complexes from xylan and chitosan were formed, characterized and adsorbed onto unbleached fibers for improving the papermaking properties. They were prepared at a level of 30% of neutralization charge ratio by modifying the order of addition of polyelectrolytes and the ionic strength (0.01N and 0.1N NaCl). The charge density, colloidal stability and particle size of polyelectrolyte complexes (PECs) was measured using polyelectrolyte titration method, Turbiscan and Zetasizer Nano equipments, respectively. All the complexes were stable even after seven days from PEC formation. DRIFT spectra of complexes were also analyzed. The adsorption behavior of them onto cellulose nanofibrils model surfaces was studied using quartz crystal microbalance with dissipation monitoring, and surface plasmon resonance. It was found that the PEC layers were viscoelastic and highly hydrated. Finally, it is shown that the adsorbed PECs onto cellulosic fibers markedly improved the tensile and crushing strengths of paper.

  9. Some Activities of MISSE 6 Mission

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.

    2009-01-01

    The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. In this paper, a few laser and optical elements from NASA Langley Research Center (LaRC) that have been flown on MISSE 6 mission will be discussed. These items were characterized and packed inside a ruggedized Passive Experiment Container (PEC) that resembles a suitcase. The PEC was tested for survivability due to launch conditions. Subsequently, the MISSE 6 PEC was transported by the STS-123 mission to International Space Station (ISS) on March 11, 2008. The astronauts successfully attached the PEC to external handrails and opened the PEC for long term exposure to the space environment. The plan is to retrieve the MISSE 6 PEC by STS-128 mission in August 2009.

  10. Improvement in the photoelectrochemical responses of PCBM/TiO2 electrode by electron irradiation

    PubMed Central

    2012-01-01

    The photoelectrochemical (PEC) responses of electron-irradiated [6,6]-phenyl-C61-butyric acid methyl ester (PCBM)/TiO2 electrodes were evaluated in a PEC cell. By coating PCBM on TiO2 nanoparticle film, the light absorption of PCBM/TiO2 electrode has expanded to the visible light region and improved the PEC responses compared to bare TiO2 electrode. The PEC responses were further improved by irradiating an electron beam on PCBM/TiO2 electrodes. Compared to non-irradiated PCBM/TiO2 electrodes, electron irradiation increased the photocurrent density and the open-circuit potential of PEC cells by approximately 90% and approximately 36%, respectively at an optimum electron irradiation condition. The PEC responses are carefully evaluated correlating with the optical and electronic properties of electron-irradiated PCBM/TiO2 electrodes. PMID:22348621

  11. Triggered Release of Encapsulated Cargo from Photoresponsive Polyelectrolyte Nanocomplexes

    PubMed Central

    2016-01-01

    Combining the numerous advantages of using light as a stimulus, simple free radical random copolymerization, and the easy, all-aqueous preparation of polyelectrolyte complexes (PECs), we prepared photolabile PEC nanoparticles and demonstrated their rapid degradation under UV light. As a proof of concept demonstration, the dye Nile Red was encapsulated in the PECs and successfully released into the surrounding solution as the polyelectrolyte nanocomplex carriers dissolved upon light irradiation. PMID:27526052

  12. A Multiepitope Subunit Vaccine Conveys Protection against Extraintestinal Pathogenic Escherichia coli in Mice▿ †

    PubMed Central

    Wieser, Andreas; Romann, Eva; Magistro, Giuseppe; Hoffmann, Christiane; Nörenberg, Dominik; Weinert, Kirsten; Schubert, Sören

    2010-01-01

    Infections due to extraintestinal pathogenic Escherichia coli (ExPEC) are common in humans and animals and include urinary tract infections (from uropathogenic E. coli [UPEC]), septicemia, and wound infections. These infections result in significant morbidity and mortality and in high health care costs. In view of the increasing number of ExPEC infections and the ever-growing antibiotic resistance capability of ExPEC isolates, preventive measures such as an effective vaccine against ExPEC are desirable. An ExPEC vaccine may be cost-effective for select patient groups. Previous vaccine candidates consisted of single target proteins or whole ExPEC cells. Here we describe a subunit vaccine against ExPEC which is based on immunodominant epitopes of the virulence-associated ExPEC proteins FyuA, IroN, ChuA, IreA, Iha, and Usp. Using a novel approach of computer-aided design, two completely artificial genes were created, both encoding eight peptide domains derived from these ExPEC proteins. The recombinant expression of these two genes resulted in a protein vaccine directed against ExPEC but not against commensal E. coli of the gut flora. In mice, the vaccine was highly immunogenic, eliciting both strong humoral and cellular immune responses. Nasal application resulted in high secretory immunoglobulin A (sIgA) production, which was detectable on the mucosal surface of the urogenital tract. Finally, it conveyed protection, as shown by a significant reduction of bacterial load in a mouse model of ExPEC peritonitis. This study provides evidence that a novel vaccine design encompassing distinct epitopes of virulence-associated ExPEC proteins may represent a means for providing a protective and pathogen-specific vaccine. PMID:20498257

  13. Simultaneous glucose sensing and biohydrogen evolution from direct photoelectrocatalytic glucose oxidation on robust Cu₂O-TiO₂ electrodes.

    PubMed

    Devadoss, Anitha; Sudhagar, P; Ravidhas, C; Hishinuma, Ryota; Terashima, Chiaki; Nakata, Kazuya; Kondo, Takeshi; Shitanda, Isao; Yuasa, Makoto; Fujishima, Akira

    2014-10-21

    We report simultaneous photoelectrocatalytic (PEC) glucose sensing and biohydrogen generation for the first time from the direct PEC oxidation of glucose at multifunctional and robust Cu2O-TiO2 photocatalysts. Striking improvement of 30% in overall H2 gas evolution (∼122 μmol h(-1) cm(-2)) by photoholes assisted glucose oxidation opens a new platform in solar-driven PEC biohydrogen generation.

  14. Extraintestinal pathogenic Escherichia coli: "the other bad E coli".

    PubMed

    Johnson, James R; Russo, Thomas A

    2002-03-01

    Extraintestinal pathogenic Escherichia coli (ExPEC), the specialized strains of E coli that cause most extraintestinal E coli infections, represent a major but little-appreciated health threat. Although the reasons for their evolution remain mysterious, by virtue of their numerous virulence traits ExPEC clearly possess a unique ability to cause disease outside the host intestinal tract. Broader appreciation of the existence and importance of ExPEC and better understandings of their distinctive virulence mechanisms, reservoirs, and transmission pathways may lead to effective preventive interventions against the morbid and costly infections ExPEC cause.

  15. Eosinophil chemotactic lymphokine produced by spleen cells of Schistosoma japonicum-infected mice. III. Isolation and characterization of two distinctive eosinophil chemotactic lymphokines directed against different maturation stages of eosinophils.

    PubMed

    Owhashi, M; Nawa, Y

    1987-01-01

    Two distinctive types of eosinophil chemotactic lymphokines (ECF-L) directed against eosinophils obtained from bone marrow (BM-Eo) or from peritoneal cavity (PEC-Eo) were isolated from the media conditioned by spleen cells from mice infected with Schistosoma japonicum by a combination of anion-exchange chromatography on DE52, affinity chromatography on Procion Red agarose, and high-performance liquid chromatography. The molecular weight of ECF-L directed against BM-Eo was 10,000 and that against PEC-Eo was 46,000 by SDS-PAGE analysis. After isolation, selectivity of the two distinct ECF-L was examined using BM-Eo, PEC-Eo and circulating Eo. ECF-L directed against BM-Eo could attract only BM-Eo, whereas that directed against PEC-Eo could attract not only PEC-Eo but also circulating Eo. Synthetic ECF-A was chemotactic against both BM- and circulating-Eo but not against PEC-Eo. When BM-Eo were cultured with ECF-L selective to PEC-Eo, they became reactive to ECF-L selective to PEC-Eo, whereas ECF-L selective to BM-Eo did not have such effect. These results suggest that ECF-L selective to PEC-Eo is not simply a chemoattractant but also is important in eosinophil differentiation.

  16. Environmental risk assessment of antibiotics: an intensive care unit analysis.

    PubMed

    de Souza, Sandra Maria Lopes; Vasconcelos, Eliane Carvalho de; Dziedzic, Maurício; de Oliveira, Cíntia Mara Ribas

    2009-11-01

    Hospital effluents have been usually known by the microbiological pollution they cause, but only recently they have been considered a significant source of aquatic environmental pollution due to the presence of medicines in these effluents. In this context, an environmental risk assessment (ERA) is presented for the most used intravenous antibiotics in the Intensive Care Unit (ICU) of a hospital in Curitiba (Brazil). The amount of antibiotics used in the ICU was evaluated during 18months (June 2006 until November 2007), in order to calculate the Predicted Environmental Concentration (PEC1). Antibiotic excretion data (on its original form) and the removal of the selected drugs in the sewage treatment plants based on the activated sludge system were used to calculate, respectively, PEC2 and PEC2r. The Predicted No-Effect Concentration (PNEC) of pharmaceuticals was also considered to assess the environmental risk by calculating the PEC/PNEC ratios. All PECs were 1ngL(-1). The worst-case PEC estimations (PEC1 and PEC2) were observed for sodic ceftriaxone, sodic cefazolin, meropenem, ampicillin, cefepime and sodic piperacillin. PEC/PNEC ratios showed that, given the present pattern of usage, high aquatic environmental risk is expected for these antibiotics. Further studies should be carried out to elucidate their contribution to increasing antimicrobial multi-drug-resistant species.

  17. Characterization of Extraintestinal Pathogenic Escherichia coli isolated from retail poultry meats from Alberta, Canada.

    PubMed

    Aslam, Mueen; Toufeer, Mehdi; Narvaez Bravo, Claudia; Lai, Vita; Rempel, Heidi; Manges, Amee; Diarra, Moussa Sory

    2014-05-02

    Extraintestinal Pathogenic Escherichia coli (ExPEC) have the potential to spread through fecal waste resulting in the contamination of both farm workers and retail poultry meat in the processing plants or environment. The objective of this study was to characterize ExPEC from retail poultry meats purchased from Alberta, Canada and to compare them with 12 human ExPEC representatives from major ExPEC lineages. Fifty-four virulence genes were screened by a set of multiplex PCRs in 700 E. coli from retail poultry meat samples. ExPEC was defined as the detection of at least two of the following virulence genes: papA/papC, sfa, kpsMT II and iutA. Genetic relationships between isolates were determined using pulsed field gel electrophoresis (PFGE). Fifty-nine (8.4%) of the 700 poultry meat isolates were identified as ExPEC and were equally distributed among the phylogenetic groups A, B1, B2 and D. Isolates of phylogenetic group A possessed up to 12 virulence genes compared to 24 and 18 genes in phylogenetic groups B2 and D, respectively. E. coli identified as ExPEC and recovered from poultry harbored as many virulence genes as those of human isolates. In addition to the iutA gene, siderophore-related iroN and fyuA were detected in combination with other virulence genes including those genes encoding for adhesion, protectin and toxin while the fimH, ompT, traT, uidA and vat were commonly detected in poultry ExPEC. The hemF, iss and cvaC genes were found in 40% of poultry ExPEC. All human ExPEC isolates harbored concnf (cytotoxic necrotizing factor 1 altering cytoskeleton and causing necrosis) and hlyD (hemolysin transport) genes which were not found in poultry ExPEC. PFGE analysis showed that a few poultry ExPEC isolates clustered with human ExPEC isolates at 55-70% similarity level. Comparing ExPEC isolated from retail poultry meats provides insight into their virulence potential and suggests that poultry associated ExPEC may be important for retail meat safety

  18. Evaluation of Escherichia coli isolates from healthy chickens to determine their potential risk to poultry and human health.

    PubMed

    Stromberg, Zachary R; Johnson, James R; Fairbrother, John M; Kilbourne, Jacquelyn; Van Goor, Angelica; Curtiss, Roy; Mellata, Melha

    2017-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) strains are important pathogens that cause diverse diseases in humans and poultry. Some E. coli isolates from chicken feces contain ExPEC-associated virulence genes, so appear potentially pathogenic; they conceivably could be transmitted to humans through handling and/or consumption of contaminated meat. However, the actual extraintestinal virulence potential of chicken-source fecal E. coli is poorly understood. Here, we assessed whether fecal E. coli isolates from healthy production chickens could cause diseases in a chicken model of avian colibacillosis and three rodent models of ExPEC-associated human infections. From 304 E. coli isolates from chicken fecal samples, 175 E. coli isolates were screened by PCR for virulence genes associated with human-source ExPEC or avian pathogenic E. coli (APEC), an ExPEC subset that causes extraintestinal infections in poultry. Selected isolates genetically identified as ExPEC and non-ExPEC isolates were assessed in vitro for virulence-associated phenotypes, and in vivo for disease-causing ability in animal models of colibacillosis, sepsis, meningitis, and urinary tract infection. Among the study isolates, 13% (40/304) were identified as ExPEC; the majority of these were classified as APEC and uropathogenic E. coli, but none as neonatal meningitis E. coli. Multiple chicken-source fecal ExPEC isolates resembled avian and human clinical ExPEC isolates in causing one or more ExPEC-associated illnesses in experimental animal infection models. Additionally, some isolates that were classified as non-ExPEC were able to cause ExPEC-associated illnesses in animal models, and thus future studies are needed to elucidate their mechanisms of virulence. These findings show that E. coli isolates from chicken feces contain ExPEC-associated genes, exhibit ExPEC-associated in vitro phenotypes, and can cause ExPEC-associated infections in animal models, and thus may pose a health threat to

  19. Kinetic Analysis of Nanoparticulate Polyelectrolyte Complex Interactions with Endothelial Cells

    PubMed Central

    Hartig, Sean M.; Greene, Rachel; Carlesso, Gianluca; Higginbotham, James N.; Khan, Wasif N.; Prokop, Ales; Davidson, Jeffrey M.

    2007-01-01

    A non-toxic, nanoparticulate polyelectrolyte complex (PEC) drug delivery system was formulated to maintain suitable physicochemical properties at physiological pH. Toxicity, binding, and internalization were evaluated in relevant microvascular endothelial cells. PEC were non-toxic, as indicated by cell proliferation studies and propidium iodide staining. Inhibitor studies revealed that PEC were bound, in part, via heparan sulfate proteoglycans and internalized through macropinocytosis. A novel, flow cytometric, Scatchard protocol was established and showed that PEC, in the absence of surface modification, bind cells non-specifically with positive cooperativity, as seen by graphical transformations. PMID:17560645

  20. Evaluation of Escherichia coli isolates from healthy chickens to determine their potential risk to poultry and human health

    PubMed Central

    Johnson, James R.; Fairbrother, John M.; Kilbourne, Jacquelyn; Van Goor, Angelica; Curtiss, Roy; Mellata, Melha

    2017-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) strains are important pathogens that cause diverse diseases in humans and poultry. Some E. coli isolates from chicken feces contain ExPEC-associated virulence genes, so appear potentially pathogenic; they conceivably could be transmitted to humans through handling and/or consumption of contaminated meat. However, the actual extraintestinal virulence potential of chicken-source fecal E. coli is poorly understood. Here, we assessed whether fecal E. coli isolates from healthy production chickens could cause diseases in a chicken model of avian colibacillosis and three rodent models of ExPEC-associated human infections. From 304 E. coli isolates from chicken fecal samples, 175 E. coli isolates were screened by PCR for virulence genes associated with human-source ExPEC or avian pathogenic E. coli (APEC), an ExPEC subset that causes extraintestinal infections in poultry. Selected isolates genetically identified as ExPEC and non-ExPEC isolates were assessed in vitro for virulence-associated phenotypes, and in vivo for disease-causing ability in animal models of colibacillosis, sepsis, meningitis, and urinary tract infection. Among the study isolates, 13% (40/304) were identified as ExPEC; the majority of these were classified as APEC and uropathogenic E. coli, but none as neonatal meningitis E. coli. Multiple chicken-source fecal ExPEC isolates resembled avian and human clinical ExPEC isolates in causing one or more ExPEC-associated illnesses in experimental animal infection models. Additionally, some isolates that were classified as non-ExPEC were able to cause ExPEC-associated illnesses in animal models, and thus future studies are needed to elucidate their mechanisms of virulence. These findings show that E. coli isolates from chicken feces contain ExPEC-associated genes, exhibit ExPEC-associated in vitro phenotypes, and can cause ExPEC-associated infections in animal models, and thus may pose a health threat to

  1. The Picture Exchange Communication System: Effects on Manding and Speech Development for School-Aged Children with Autism

    ERIC Educational Resources Information Center

    Tincani, Matt; Crozier, Shannon; Alazett, Shannon

    2006-01-01

    We examined the effects of the Picture Exchange Communication System (PECS; Frost & Bondy, 2002) on the manding (requesting) and speech development of school-aged children with autism. In study 1, two participants, Damian and Bob, were taught PECS within a delayed multiple baseline design. Both participants demonstrated increased levels of manding…

  2. Principles and applications of photoelectrochemical sensing strategies based on biofunctionalized nanostructures.

    PubMed

    Zang, Yang; Lei, Jianping; Ju, Huangxian

    2017-10-15

    Photoelectrochemical (PEC) biosensing is a popular research hotspot that has attracted substantial attention from chemists and biologists due to its low cost and desirable sensitivity. The PEC biosensing mainly refers to the influence of the interaction between recognition element and analyte on photocurrent signal, which involves the charge and energy transfer of PEC reaction between electron donor/acceptor and photoactive material upon light irradiation. Understanding the fundamentals of PEC strategy benefits the development of next-generation PEC sensors. However, the research on detection mechanism of PEC sensors is in the initial stage and need to be further exploited. Thus, with a particular focus on the signal transduction formats, this review highlights the novel concept on PEC sensing strategies, and categorizes the recent illustrative examples into three signaling principles: reactant determinant, electron transfer and energy transfer, providing the comprehensive design guidelines for researchers to develop more advanced PEC sensors. The prospects and challenges for future work are also included. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. An Evaluation of Strategies for Training Staff to Implement the Picture Exchange Communication System

    ERIC Educational Resources Information Center

    Barnes, Clarissa S.; Dunning, Johnna L.; Rehfeldt, Ruth Anne

    2011-01-01

    The picture exchange communication system (PECS) is a functional communication system frequently used with individuals diagnosed with autism spectrum disorders who experience severe language delays (Frost & Bondy, 2002). Few empirical investigations have evaluated strategies for training direct care staff how to effectively implement PECS with…

  4. Visions of Peace Education: Interviews with the Five Former Executive Secretaries of the Peace Education Commission. Educational Information Debate 99.

    ERIC Educational Resources Information Center

    Bjerstedt, Ake, Ed.

    The Peace Education Commission (PEC), a subgroup of the IPRA (The International Peace Research Association), was established to facilitate international cooperation among individuals interested in peace education and research related to peace education. PEC is coordinated by a Council and an Executive Secretary (at present Ake Bjerstedt). The full…

  5. Effectiveness of Combining Tangible Symbols with the Picture Exchange Communication System to Teach Requesting Skills to Children with Multiple Disabilities Including Visual Impairment

    ERIC Educational Resources Information Center

    Ali, Emad; MacFarland, Stephanie Z.; Umbreit, John

    2011-01-01

    The Picture Exchange Communication System (PECS) is an augmentative and alternative communication (AAC) program used to teach functional requesting and commenting skills to people with disabilities (Bondy & Frost, 1993; Frost & Bondy, 2002). In this study, tangible symbols were added to PECS in teaching requesting to four students (ages 7-14) with…

  6. Parental Empowerment in Mexico: Randomized Experiment of the "Apoyos a La Gestion Escolar (Age)" Program in Rural Primary Schools in Mexico

    ERIC Educational Resources Information Center

    Gertler, Paul; Patrinos, Harry Anthony; Rodriguez-Oreggia, Eduardo

    2012-01-01

    Previous evaluations from Mexico are limited. The urban school-based management program, Programa Escuelas de Calidad (PEC), was analyzed using panel data regression analysis and propensity score matching. Participation in PEC is found to lead to decreases in dropout, failure and repetition rates. An evaluation of the rural parental empowerment…

  7. Analysis of Features for Synthetic Aperture Radar Target Classification

    DTIC Science & Technology

    2015-03-26

    gradients HPC high performance computing LDA linear discriminant analysis PEC perfect electric conductor RVM relevance vector machine SAR synthetic...the polarization of the re-radiated field. When a linearly polarized electric field is incident on a flat perfect electric conductor (PEC), the

  8. 3D WO3 /BiVO4 /Cobalt Phosphate Composites Inverse Opal Photoanode for Efficient Photoelectrochemical Water Splitting.

    PubMed

    Zhang, Haifeng; Zhou, Weiwei; Yang, Yaping; Cheng, Chuanwei

    2017-04-01

    A novel 3D WO3 /BiVO4 /cobalt phosphate composite inverse opal is designed for photoeletrochemical (PEC) water splitting, yielding a significantly improved PEC performance. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A Communication-Based Intervention for Nonverbal Children with Autism: What Changes? Who Benefits?

    ERIC Educational Resources Information Center

    Gordon, Kate; Pasco, Greg; McElduff, Fiona; Wade, Angie; Howlin, Pat; Charman, Tony

    2011-01-01

    Objective: This article examines the form and function of spontaneous communication and outcome predictors in nonverbal children with autism following classroom-based intervention (Picture Exchange Communication System [PECS] training). Method: 84 children from 15 schools participated in a randomized controlled trial (RCT) of PECS (P. Howlin, R.…

  10. Possible role of the Ec peptide of IGF-1Ec in cartilage repair

    PubMed Central

    Armakolas, Nikolaos; Dimakakos, Andreas; Armakolas, Athanasios; Antonopoulos, Athanasios; Koutsilieris, Michael

    2016-01-01

    The Ec peptide (PEc) of insulin-like growth factor 1 Ec (IGF-1Ec) induces human mesenchymal stem cell (hMSC) mobilization and activates extracellular signal-regulated kinase 1/2 (ERK 1/2) in various cells. The aim of the present study was to examine the effects of PEc on the mobilization and differentiation of hMSCs, as well as the possibility of its implementation in combination with transforming growth factor β1 (TGF-β1) for cartilage repair. The effects of the exogenous administration of PEc and TGF-β1, alone and in combination, on hMSCs were assessed using a trypan blue assay, reverse transcription-quantitative polymerase chain reaction, western blot analysis, Alcian blue staining, wound healing assays and migration/invasion assays. It was determined that PEc is involved in the differentiation process of hMSCs towards hyaline cartilage. Treatment of hMSCs with either PEc, TGF-β1 or both, demonstrated comparable cartilage matrix deposition. Furthermore, treatment with PEc in combination with TGF-β1 was associated with a significant increase in hMSC mobilization when compared with treatment with TGF-β1 or PEc alone (P<0.05). Thus, PEc appears to facilitate in vitro hMSC mobilization and differentiation towards chondrocytes, enhancing the role of TGF-β1. PMID:27571686

  11. Quantitative Synthesis and Component Analysis of Single-Participant Studies on the Picture Exchange Communication System

    ERIC Educational Resources Information Center

    Tincani, Matt; Devis, Kathryn

    2011-01-01

    The "Picture Exchange Communication System" (PECS) has emerged as the augmentative communication intervention of choice for individuals with autism spectrum disorder (ASD), with a supporting body of single-participant studies. This report describes a meta-analysis of 16 single-participant studies on PECS with percentage of nonoverlapping data…

  12. Modeling the inactivatin of Escherichia coli 0157:H7 and uropathogenic E. coli in ground beef by high pressure processing and citral

    USDA-ARS?s Scientific Manuscript database

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in ground beef using High Pressure Processing...

  13. Photoelectrochemical Solar Cells.

    ERIC Educational Resources Information Center

    McDevitt, John T.

    1984-01-01

    This introduction to photoelectrochemical (PEC) cells reviews topics pertaining to solar energy conversion and demonstrates the ease with which a working PEC cell can be prepared with n-type silicon as the photoanode and a platinum counter electrode (both immersed in ethanolic ferrocene/ferricenium solutions). Experiments using the cell are…

  14. 76 FR 76156 - Grand Coulee Project Hydroelectric Authority; Notice of Preliminary Permit Application Accepted...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-06

    ... Energy Regulatory Commission Grand Coulee Project Hydroelectric Authority; Notice of Preliminary Permit... the PEC 1973 Drop Hydroelectric Project (PEC 1973 Project or project) to be located on the Potholes.... Applicant Contact: Mr. Ronald Rodewald, Secretary-Manager, Grand Coulee Project Hydroelectric Authority, P.O...

  15. Using the Picture Exchange Communication System with Students with Visual Impairment

    ERIC Educational Resources Information Center

    Ivy, Sarah E.; Hatton, Deborah D.; Hooper, Jonathan D.

    2014-01-01

    Students with visual impairment (VI) were taught to request using the Picture Exchange Communication System (PECS) and tangible symbols. Participants were four males with additional disabilities, 5 to 11 years old, who had little to no functional vision. A functional relation between PECS Phase 1 and requesting was established using a multiple…

  16. A Review of the Efficacy of the Picture Exchange Communication System Intervention

    ERIC Educational Resources Information Center

    Preston, Deborah; Carter, Mark

    2009-01-01

    The Picture Exchange Communication System (PECS) is a communication program that has become widely used, especially with children with autism. This paper reports the results of a review of the empirical literature on PECS. A descriptive review is provided of the 27 studies identified, which included randomized controlled trials (RCTs), other group…

  17. Action pattern of Valencia orange PME de-esterification of high methoxyl pectin and characterization of modified pectins.

    PubMed

    Kim, Yookyung; Teng, Quincy; Wicker, Louise

    2005-12-12

    Valencia pectinmethylesterase (PME) fractions, B-PME, containing 36 and 13 kDa protein bands and U-PME, containing a 36 and 27 kDa protein bands, were used to de-esterify original pectin (O-Pec) from 73% degree of esterification (%DE) to 63% (B-Pec) and 61% DE (U-Pec), respectively. Most O-Pec eluted from ion exchange chromatography at low salt concentration and a smaller component eluted at higher ionic strength. B-Pec and U-Pec eluted as one broad peak at higher ionic strength. PME modification did not change molecular weight: O-pectin (134,000 g/mol), U-Pec (133,850 g/mol), and B-Pec (132,250 g/mol). The NMR signal of GG and GGG increased after modification, whereas the signal of EE and EEE decreased. The negative zeta-potential increased with pH for all pectins. U-PME and B-PME created differently modified pectins that vary in degree and length of multiple attacks and fraction of the pectin population that was modified.

  18. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE (PAPER)

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  19. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  20. Pesticide Environmental Fate Research for the 21st Century: Building Bridges Between Laboratory and Field Studies at Varying Scales

    USDA-ARS?s Scientific Manuscript database

    Accurate determination of predicted environmental concentrations (PECs) is a continuing and often elusive goal of pesticide risk assessment. PECs are typically derived using simulation models that depend on laboratory generated data for key input parameters (t1/2, Koc, etc.). Model flexibility in ...

  1. Annual Surveillance Summary: Escherichia coli (E. coli) Infections in the Military Health System (MHS), 2015

    DTIC Science & Technology

    2017-03-01

    healthcare- associated exposures, Defense Manpower Data Center (DMDC) rosters to determine burden among Department of Defense (DOD) active duty (AD...ExPEC and E. coli interchangeably. ExPEC are associated with a variety of diseases including gastroenteritis, urinary tract infections (UTIs...genome diversity and have a wide range of virulence- associated factors including adhesions, toxins, lipopolysaccharides, polysaccharide capsules

  2. Materials International Space Station Experiment (MISSE) 5 Developed to Test Advanced Solar Cell Technology Aboard the ISS

    NASA Technical Reports Server (NTRS)

    Wilt, David M.

    2004-01-01

    The testing of new technologies aboard the International Space Station (ISS) is facilitated through the use of a passive experiment container, or PEC, developed at the NASA Langley Research Center. The PEC is an aluminum suitcase approximately 2 ft square and 5 in. thick. Inside the PEC are mounted Materials International Space Station Experiment (MISSE) plates that contain the test articles. The PEC is carried to the ISS aboard the space shuttle or a Russian resupply vehicle, where astronauts attach it to a handrail on the outer surface of the ISS and deploy the PEC, which is to say the suitcase is opened 180 deg. Typically, the PEC is left in this position for approximately 1 year, at which point astronauts close the PEC and it is returned to Earth. In the past, the PECs have contained passive experiments, principally designed to characterize the durability of materials subjected to the ultraviolet radiation and atomic oxygen present at the ISS orbit. The MISSE5 experiment is intended to characterize state-of-art (SOA) and beyond photovoltaic technologies.

  3. A Communication-Based Intervention for Nonverbal Children with Autism: What Changes? Who Benefits?

    ERIC Educational Resources Information Center

    Gordon, Kate; Pasco, Greg; McElduff, Fiona; Wade, Angie; Howlin, Pat; Charman, Tony

    2011-01-01

    Objective: This article examines the form and function of spontaneous communication and outcome predictors in nonverbal children with autism following classroom-based intervention (Picture Exchange Communication System [PECS] training). Method: 84 children from 15 schools participated in a randomized controlled trial (RCT) of PECS (P. Howlin, R.…

  4. Photoelectrochemical Solar Cells.

    ERIC Educational Resources Information Center

    McDevitt, John T.

    1984-01-01

    This introduction to photoelectrochemical (PEC) cells reviews topics pertaining to solar energy conversion and demonstrates the ease with which a working PEC cell can be prepared with n-type silicon as the photoanode and a platinum counter electrode (both immersed in ethanolic ferrocene/ferricenium solutions). Experiments using the cell are…

  5. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  6. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE (PAPER)

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  7. Characterization of phycoviolobilin phycoerythrocyanin-alpha 84-cystein-lyase-(isomerizing) from Mastigocladus laminosus.

    PubMed

    Zhao, Kai-Hong; Wu, Dong; Wang, Lu; Zhou, Ming; Storf, Max; Bubenzer, Claudia; Strohmann, Brigitte; Scheer, Hugo

    2002-09-01

    Cofactor requirements and enzyme kinetics have been studied of the novel, dual-action enzyme, the isomerizing phycoviolobilin phycoerythrocyanin-alpha84-cystein-lyase(PVB-PEC-lyase) from Mastigocladus laminosus, which catalyses both the covalent attachment of phycocyanobilin to PecA, the apo-alpha-subunit of phycoerythrocyanin, and its isomerization to phycoviolobilin. Thiols and the divalent metals, Mg2+ or Mn2+, were required, and the reaction was aided by the detergent, Triton X-100. Phosphate buffer inhibits precipitation of the proteins present in the reconstitution mixture, but at the same time binds the required metal. Kinetic constants were obtained for both substrates, the chromophore (Km = 12-16 micro m, depending on [PecA], kcat approximately 1.2 x 10-4.s-1) and the apoprotein (Km = 2.4 micro m at 14 micro m PCB, kcat = 0.8 x 10-4.s-1). The kinetic analysis indicated that the reconstitution reaction proceeds by a sequential mechanism. By a combination of untagged and His-tagged subunits, evidence was obtained for a complex formation between PecE and PecF (subunits of PVB-PEC-lyase), and by experiments with single subunits for the prevalent function of PecE in binding and PecF in isomerizing the chromophore.

  8. The Picture Exchange Communication System: Effects on Manding and Speech Development for School-Aged Children with Autism

    ERIC Educational Resources Information Center

    Tincani, Matt; Crozier, Shannon; Alazett, Shannon

    2006-01-01

    We examined the effects of the Picture Exchange Communication System (PECS; Frost & Bondy, 2002) on the manding (requesting) and speech development of school-aged children with autism. In study 1, two participants, Damian and Bob, were taught PECS within a delayed multiple baseline design. Both participants demonstrated increased levels of manding…

  9. The Effectiveness of Combining Tangible Symbols with the Picture Exchange Communication System to Teach Requesting Skills to Children with Multiple Disabilities Including Visual Impairment

    ERIC Educational Resources Information Center

    Ali, Emad

    2009-01-01

    The Picture Exchange Communication System (PECS) is an augmentative and alternative communication program (Frost & Bondy, 2002). Although PECS has been effectively used to teach functional requesting skills for children with autism, mental retardation, visual impairment, and physical disabilities (e.g., Anderson, Moore, & Bourne, 2007; Chambers &…

  10. An Evaluation of Strategies for Training Staff to Implement the Picture Exchange Communication System

    ERIC Educational Resources Information Center

    Barnes, Clarissa S.; Dunning, Johnna L.; Rehfeldt, Ruth Anne

    2011-01-01

    The picture exchange communication system (PECS) is a functional communication system frequently used with individuals diagnosed with autism spectrum disorders who experience severe language delays (Frost & Bondy, 2002). Few empirical investigations have evaluated strategies for training direct care staff how to effectively implement PECS with…

  11. Black Leadership and Outside Allies in Virginia Freedom Schools

    ERIC Educational Resources Information Center

    Bonastia, Christopher

    2016-01-01

    In July 1963, students from Queens College (QC) and a group of New York City teachers traveled to Prince Edward County (PEC), Virginia, to teach local black youth in Freedom Schools. The county had eliminated public education four years earlier to avoid a desegregation order. PEC Freedom Schools represented the first major effort to recruit an…

  12. 77 FR 69591 - President's Export Council: Meeting of the President's Export Council

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-20

    ... Council Web site at http://trade.gov/pec . DATES: December 6, 2012 at 8:00 a.m. (ET). ADDRESSES: The President's Export Council meeting will be broadcast via live webcast on the Internet at http://whitehouse... electronically via the President's Export Council Web site at http://trade.gov/pec/peccomments.asp ; or...

  13. Black Leadership and Outside Allies in Virginia Freedom Schools

    ERIC Educational Resources Information Center

    Bonastia, Christopher

    2016-01-01

    In July 1963, students from Queens College (QC) and a group of New York City teachers traveled to Prince Edward County (PEC), Virginia, to teach local black youth in Freedom Schools. The county had eliminated public education four years earlier to avoid a desegregation order. PEC Freedom Schools represented the first major effort to recruit an…

  14. Modeling the inactivation of Escherichia coli 0157:H7 and uropathogenic E.coli in ground chicken by high pressure processing and thymol

    USDA-ARS?s Scientific Manuscript database

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compare the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing...

  15. Pesticide Environmental Fate Research for the 21st Century: Building Bridges Between Laboratory and Field Studies at Varying Scales

    USDA-ARS?s Scientific Manuscript database

    Accurate determination of predicted environmental concentrations (PECs) is a continuing and often elusive goal of pesticide risk assessment. PECs are typically derived using simulation models that depend on laboratory generated data for key input parameters (t1/2, Koc, etc.). Model flexibility in ev...

  16. Extraintestinal pathogenic Escherichia coli in poultry meat products on the Finnish retail market.

    PubMed

    Lyhs, Ulrike; Ikonen, Ilona; Pohjanvirta, Tarja; Raninen, Kaisa; Perko-Mäkelä, Päivikki; Pelkonen, Sinikka

    2012-11-16

    Extraintestinal pathogenic Escherichia coli bacteria (ExPEC) exist as commensals in the human intestines and can infect extraintestinal sites and cause septicemia. The transfer of ExPEC from poultry to humans and the role of poultry meat as a source of ExPEC in human disease have been discussed previously. The aim of the present study was to provide insight into the properties of ExPEC in poultry meat products on the Finnish retail market with special attention to their prevalence, virulence and phylogenetic profiles. Furthermore, the isolates were screened for possible ESBL producers and their resistance to nalidixic acid and ciprofloxacin was tested. The presence of ExPEC in 219 marinated and non-marinated raw poultry meat products from retail shops has been analyzed. One E. coli strain per product was analyzed further for phylogenetic groups and possession of ten virulence genes associated with ExPEC bacteria (kpsMT K1, ibeA, astA, iss, irp2, papC, iucD, tsh, vat and cva/cv) using PCR methods. The E. coli strains were also screened phenotypically for the production of extended-spectrum β-lactamase (ESBL) and the susceptibility of 48 potential ExPEC isolates for nalidixic acid and ciprofloxacin was tested. E. coli was isolated from 207 (94.5%) of 219 poultry meat products. The most common phylogenetic groups were D (50.7%), A (37.7%), and B2 (7.7%). Based on virulence factor gene PCR, 23.2% of the strains were classified as ExPEC. Two ExPEC strains (1%) belonged to [O1] B2 svg+ (specific for virulent subgroup) group, which has been implicated in multiple forms of ExPEC disease. None of the ExPEC strains was resistant to ciprofloxacin or cephalosporins. One isolate (2.1%) showed resistance to nalidixic acid. Potential ExPEC bacteria were found in 22% of marinated and non-marinated poultry meat products on the Finnish retail market and 0.9% were contaminated with E. coli [O1] B2 svg+ group. Marinades did not have an effect on the survival of ExPEC as strains from

  17. Extraintestinal pathogenic Escherichia coli in poultry meat products on the Finnish retail market

    PubMed Central

    2012-01-01

    Background Extraintestinal pathogenic Escherichia coli bacteria (ExPEC) exist as commensals in the human intestines and can infect extraintestinal sites and cause septicemia. The transfer of ExPEC from poultry to humans and the role of poultry meat as a source of ExPEC in human disease have been discussed previously. The aim of the present study was to provide insight into the properties of ExPEC in poultry meat products on the Finnish retail market with special attention to their prevalence, virulence and phylogenetic profiles. Furthermore, the isolates were screened for possible ESBL producers and their resistance to nalidixic acid and ciprofloxacin was tested. Methods The presence of ExPEC in 219 marinated and non-marinated raw poultry meat products from retail shops has been analyzed. One E. coli strain per product was analyzed further for phylogenetic groups and possession of ten virulence genes associated with ExPEC bacteria (kpsMT K1, ibeA, astA, iss, irp2, papC, iucD, tsh, vat and cva/cv) using PCR methods. The E. coli strains were also screened phenotypically for the production of extended-spectrum β-lactamase (ESBL) and the susceptibility of 48 potential ExPEC isolates for nalidixic acid and ciprofloxacin was tested. Results E. coli was isolated from 207 (94.5%) of 219 poultry meat products. The most common phylogenetic groups were D (50.7%), A (37.7%), and B2 (7.7%). Based on virulence factor gene PCR, 23.2% of the strains were classified as ExPEC. Two ExPEC strains (1%) belonged to [O1] B2 svg+ (specific for virulent subgroup) group, which has been implicated in multiple forms of ExPEC disease. None of the ExPEC strains was resistant to ciprofloxacin or cephalosporins. One isolate (2.1%) showed resistance to nalidixic acid. Conclusions Potential ExPEC bacteria were found in 22% of marinated and non-marinated poultry meat products on the Finnish retail market and 0.9% were contaminated with E. coli [O1] B2 svg+ group. Marinades did not have an effect on

  18. Review of recent progress in unassisted photoelectrochemical water splitting: from material modification to configuration design

    NASA Astrophysics Data System (ADS)

    Peerakiatkhajohn, Piangjai; Yun, Jung-Ho; Wang, Songcan; Wang, Lianzhou

    2017-01-01

    Photoelectrochemical (PEC) energy conversion systems have been considered as a highly potential strategy for clean solar fuel production, simultaneously addressing the energy and environment challenges we are facing. Tremendous research efforts have been made to design and develop feasible unassisted PEC systems that can efficiently split water into hydrogen (H2) and oxygen with only the energy input of sunlight. A fundamental understanding of the concepts involved in PEC water splitting and energy conversion efficiency enhancement for solar fuel production is important for better system design. This review gives a concise overview of the unassisted PEC devices with some state-of-the-art progress toward efficient PEC devices for future sustainable solar energy utilization.

  19. MISSE 6-Testing Materials in Space

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S; Kinard, William H.

    2008-01-01

    The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment by placing them in space environment for several months. In this paper, a few materials and components from NASA Langley Research Center (LaRC) that have been flown on MISSE 6 mission will be discussed. These include laser and optical elements for photonic devices. The pre-characterized MISSE 6 materials were packed inside a ruggedized Passive Experiment Container (PEC) that resembles a suitcase. The PEC was tested for survivability due to launch conditions. Subsequently, the MISSE 6 PEC was transported by the STS-123 mission to International Space Station (ISS) on March 11, 2008. The astronauts successfully attached the PEC to external handrails and opened the PEC for long term exposure to the space environment.

  20. Quantum-dots-based photoelectrochemical bioanalysis highlighted with recent examples.

    PubMed

    Zhang, Nan; Zhang, Ling; Ruan, Yi-Fan; Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

    2017-03-07

    Photoelectrochemical (PEC) bioanalysis is a newly developed methodology that provides an exquisite route for innovative biomolecular detection. Quantum dots (QDs) are semiconductor nanocrystals with unique photophysical properties that have attracted tremendous attentions among the analytical community. QDs-based PEC bioanalysis comprises an important research hotspot in the field of PEC bioanalysis due to its combined advantages and potentials. Currently, it has ignited increasing interests as demonstrated by increased research papers. This review aims to cover the most recent advances in this field. With the discussion of recent examples of QDs-PEC bioanalysis from the literatures, special emphasis will be placed on work reporting on fundamental advances in the signaling strategies of QDs-based PEC bioanalysis from 2013 to now. Future prospects in this field are also discussed.

  1. Modeling and Simulations in Photoelectrochemical Water Oxidation: From Single Level to Multiscale Modeling.

    PubMed

    Zhang, Xueqing; Bieberle-Hütter, Anja

    2016-06-08

    This review summarizes recent developments, challenges, and strategies in the field of modeling and simulations of photoelectrochemical (PEC) water oxidation. We focus on water splitting by metal-oxide semiconductors and discuss topics such as theoretical calculations of light absorption, band gap/band edge, charge transport, and electrochemical reactions at the electrode-electrolyte interface. In particular, we review the mechanisms of the oxygen evolution reaction, strategies to lower overpotential, and computational methods applied to PEC systems with particular focus on multiscale modeling. The current challenges in modeling PEC interfaces and their processes are summarized. At the end, we propose a new multiscale modeling approach to simulate the PEC interface under conditions most similar to those of experiments. This approach will contribute to identifying the limitations at PEC interfaces. Its generic nature allows its application to a number of electrochemical systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effect of charge balance and dosage of polyelectrolyte complexes on the shear resistance of mineral floc strength and reversibility.

    PubMed

    Korhonen, Markus H J; Rojas, Orlando J; Laine, Janne

    2015-06-15

    We evaluated the effect of polyelectrolyte complexes (PEC) with varying balance of charges on the flocculation of precipitated calcium carbonate (PCC) particles. PECs composed of polyacrylamides carrying opposite charges (A-PAM and C-PAM) were investigated in terms of PCC floc shear resistance and re-flocculation effects. Light transmission was used in real time to monitor the dynamics of flocculation under shear fields. Compared to the single polyelectrolytes, PECs greatly enhanced particle re-flocculation while minor differences in shear resistance were observed. Shear resistance and re-flocculation depended strongly on the molecular weight and charge ratio of the PEC components. In order to achieve floc stability and re-flocculation conditions a minimum concentration of charge-asymmetric PEC should be applied.

  3. Endosomal acidification and cathepsin L activity is required for calicivirus replication.

    PubMed

    Shivanna, Vinay; Kim, Yunjeong; Chang, Kyeong-Ok

    2014-09-01

    The role of cellular proteases and endosome maturation in the entry of caliciviruses including porcine enteric calicivirus (PEC), murine norovirus (MNV)-1 and feline calicivirus (FCV) were investigated. Treatment with chloroquine or cathepsin L inhibitors, but not cathepsin B inhibitors, significantly reduced the replication of PEC, MNV and FCV. When concentrated PEC, MNV or FCV were incubated with recombinant cathepsin L, the minor capsid protein VP2 of PEC and the major capsid protein VP1 of MNV and FCV were cleaved by the protease based on the Western blot analysis. Confocal microscopy analysis of PEC and MNV-1 showed that viral capsid proteins were retained in the endosomes in the presence of a cathepsin L inhibitor or chloroquine during virus entry. The results of this study suggest the important role of endosome maturation and cathepsin L in the entry of caliciviruses, and cathepsin L as a potential therapeutic target for calicivirus infection. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Endosomal acidification and cathepsin L activity is required for calicivirus replication

    PubMed Central

    Shivanna, Vinay; Kim, Yunjeong; Chang, Kyeong-Ok

    2014-01-01

    The role of cellular proteases and endosome maturation in the entry of caliciviruses including porcine enteric calicivirus (PEC), murine norovirus (MNV)-1 and feline calicivirus (FCV) were investigated. Treatment with chloroquine or cathepsin L inhibitors, but not cathepsin B inhibitors, significantly reduced the replication of PEC, MNV and FCV. When concentrated PEC, MNV or FCV were incubated with recombinant cathepsin L, the minor capsid protein VP2 of PEC or the major capsid protein VP1 of MNV and FCV were cleaved by the protease based on the Western blot analysis. Confocal microscopy analysis of PEC and MNV-1 showed that viral capsid proteins were retained in the endosomes in the presence of a cathepsin L inhibitor or chloroquine during virus entry. The results of this study suggest the important role of endosome maturation and cathepsin L in the entry of caliciviruses, and cathepsin L as a potential therapeutic target for calicivirus infection. PMID:25108379

  5. Investigation of photoelectrochemical-oxidized p-GaSb films

    SciTech Connect

    Lee, Hsin-Ying; Huang, Hung-Lin; Lee, Ching-Ting; Petrovich Pchelyakov, Oleg; Andreevich Pakhanov, Nikolay

    2012-12-17

    GaSb oxide films were directly formed on the p-GaSb films using the bias-assisted photoelectrochemical (PEC) oxidation method. X-ray photoelectron spectroscopy analysis indicated that the resulting GaSb oxide films consisted of Ga{sub 2}O{sub 3}, Sb{sub 2}O{sub 3}, and Sb{sub 2}O{sub 5}. Different from the non-PEC oxides, the PEC derived oxide contained much more Sb{sub 2}O{sub 5} than Sb{sub 2}O{sub 3}. Besides, the interface state density between the PEC oxide and p-GaSb was lower than that of the ordinary oxide/p-GaSb interface. The high quality of the PEC-oxidized GaSb films was attributed to the increase of the stable Sb{sub 2}O{sub 5} content and decrease of the elemental Sb content in the films.

  6. Molecular Characterization of a Porcine Enteric Calicivirus Genetically Related to Sapporo-Like Human Caliciviruses

    PubMed Central

    Guo, M.; Chang, K. O.; Hardy, M. E.; Zhang, Q.; Parwani, A. V.; Saif, L. J.

    1999-01-01

    Porcine enteric calicivirus (PEC) is associated with diarrhea in pigs, and to date it is the only cultivable enteric calicivirus (tissue culture-adapted [TC] PEC/Cowden). Based on sequence analysis of cDNA clones and reverse transcription-PCR products, TC PEC/Cowden has an RNA genome of 7,320 bp, excluding its 3′ poly(A)+ tail. The genome is organized in two open reading frames (ORFs), similar to the organizations of the human Sapporo-like viruses (SLVs) and the lagoviruses. ORF1 encodes the polyprotein that is fused to and contiguous with the capsid protein. ORF2 at the 3′ end encodes a small basic protein of 164 amino acids. Among caliciviruses, PEC has the highest amino acid sequence identities in the putative RNA polymerase (66%), 2C helicase (49.6%), 3C-like protease (43.7%), and capsid (39%) regions with the SLVs, indicating that PEC is genetically most closely related to the SLVs. The complete RNA genome of wild-type (WT) PEC/Cowden was also sequenced. Sequence comparisons revealed that the WT and TC PEC/Cowden have 100% nucleotide sequence identities in the 5′ terminus, 2C helicase, ORF2, and the 3′ nontranslated region. TC PEC/Cowden has one silent mutation in its protease, two amino acid changes and a silent mutation in its RNA polymerase, and five nucleotide substitutions in its capsid that result in one distant and three clustered amino acid changes and a silent mutation. These substitutions may be associated with adaptation of TC PEC/Cowden to cell culture. The cultivable PEC should be a useful model for studies of the pathogenesis, replication, and possible rescue of uncultivable human enteric caliciviruses. PMID:10516074

  7. Regulation of pelD and pelE, Encoding Major Alkaline Pectate Lyases in Erwinia chrysanthemi: Involvement of the Main Transcriptional Factors

    PubMed Central

    Rouanet, Carine; Nomura, Kinya; Tsuyumu, Shinji; Nasser, William

    1999-01-01

    The main virulence factors of the phytopathogenic bacterium Erwinia chrysanthemi are pectinases which attack pectin, the major constituent of the plant cell wall. Of these enzymes, the alkaline isoenzyme named PelD in strain 3937 and PelE in strain EC16 has been described as being particularly important, based on virulence studies of plants. Expression of the pelD and pelE genes is tightly modulated by various regulators, including the KdgR repressor and the cyclic AMP-cyclic AMP receptor protein (CRP) activator complex. The use of a lacZ reporter gene allowed us to quantify the repression of E. chrysanthemi 3937 pelD expression exerted by PecS, another repressor of pectinase synthesis. In vitro DNA-protein interaction experiments, centered on the pelD and pelE wild-type or pelE mutated promoter regions, allowed us to define precisely the sequences involved in the binding of these three regulators and of RNA polymerase (RNAP). These studies revealed an unusual binding of the KdgR repressor and suggested the presence of a UP (upstream) element in the pelD and pelE genes. Investigation of the simultaneous binding of CRP, KdgR, PecS, and the RNAP to the regulatory region of the pelD and pelE genes showed that (i) CRP and RNAP bind cooperatively, (ii) PecS partially inhibits binding of the CRP activator and of the CRP-RNAP complex, and (iii) KdgR stabilizes the binding of PecS and prevents transcriptional initiation by RNAP. Taken together, our data suggest that PecS attenuates pelD and pelE expression rather than acting as a true repressor like KdgR. Overall, control of the pelD and pelE genes of E. chrysanthemi appears to be both complex and novel. PMID:10498706

  8. Surface-induced rearrangement of polyelectrolyte complexes: influence of complex composition on adsorbed layer properties.

    PubMed

    Ondaral, Sedat; Ankerfors, Caroline; Odberg, Lars; Wågberg, Lars

    2010-09-21

    The adsorption characteristics of two different types of polyelectrolyte complexes (PECs), prepared by mixing poly(allylamine hydrochloride) and poly(acrylic acid) in a confined impinging jet (CIJ) mixer, have been investigated with the aid of stagnation point adsorption reflectometry (SPAR), a quartz crystal microbalance with dissipation (QCM-D), and atomic force microscopy (AFM) using SiO(2) surfaces. The two sets of PEC were prepared by combining high molecular mass PAH/PAA (PEC-A) and low molecular mass PAH/PAA (PEC-B). The PEC-A showed a higher adsorption to the SiO(2) surfaces than the PEC-B. The adsorption of the PEC-A also showed a larger change in the dissipation (ΔD), according to the QCM-D measurements, suggesting that the adsorbed layer of these complexes had a relatively lower viscosity and a lower shear modulus. Complementary investigations of the adsorbed layer using AFM imaging showed that the adsorbed layer of PEC-A was significantly different from that of PEC-B and that the changes in properties with adsorption time were very different for the two types of PECs. The PEC-A complexes showed a coalescence into larger block of complexes on the SiO(2) surface, but this was not detected with the PEC-B. The size determinations of the complexes in solution showed that they were very stable over time, and it was therefore concluded that the coalescence of the complexes was induced by the interaction between the complexes and the surface. The results also indicated that polyelectrolytes can migrate between the different complexes adsorbed to the surface. The results also give indications that the preparation of PEC-B leads to the formation of two different types of polyelectrolyte complexes differing in the amount of polymer in the complexes; i.e., two populations of complexes were formed with similar sizes but with totally different adsorption structures at the solid-liquid interface.

  9. Stable organic-inorganic hybrid multilayered photoelectrochemical cells

    NASA Astrophysics Data System (ADS)

    Park, Sun-Young; Kim, Min-gyeong; Jung, Jaehoon; Heo, Jinhee; Hong, Eun Mi; Choi, Sung Mook; Lee, Joo-Yul; Cho, Shinuk; Hong, Kihyon; Lim, Dong Chan

    2017-02-01

    The production of hydrogen from water via solar energy conversion has attracted immense attention as a potential solution for addressing energy supply issues. We demonstrated a stable and efficient organic-inorganic hybrid photoelectrochemical (H-PEC) cell. Modifying the surface energy and structure of the organic photoactive layer using multi-functional nanomaterials including -OH-modified NiO nanoparticles and reduced graphene oxide (RGO) led to a 2.8-fold enhancement of the water splitting performance in a single junction H-PEC cell. The enhanced performance was attributed to the i) improved water-wettability, ii) enhanced charge extraction property by band-edge alignment, and iii) the catalytic effect of the introduced NiO-OH nanoparticles. In addition, because of the effects of the RGO layer preventing water penetration and photo-corrosion during the oxidation of water, a distinguishable long-term stability was achieved from the H-PEC cell with an RGO capping layer. The best performance was obtained from the organic-inorganic hybrid multi-junction PEC cells consisting of the WO3 photo-anode (activated under UV irradiation) and the H-PEC cell (activated under visible light irradiation). The H-PEC cell with a WO3 photo-anode exhibited significantly enhanced stability and performance by a factor of 11.6 higher than photocurrent of the single H-PEC cell.

  10. Enhancement of sustained and controlled protein release using polyelectrolyte complex-loaded injectable and thermosensitive hydrogel.

    PubMed

    Park, Mi-Ran; Chun, Changju; Cho, Chong-Su; Song, Soo-Chang

    2010-10-01

    In this study, we aimed at developing controlled and sustained protein release formulations using a combination system of polyelectrolyte complexes (PECs) and thermosensitive poly(organophosphazene) hydrogels as an injectable gel-depot system. In the protein-loaded hydrogel system, the loaded proteins were released rapidly through diffusion regardless of viscosities and mass loss of the gels because of the small hydrodynamic size of the proteins. To suppress protein diffusion and increase protein size, we induced PECs between negatively charged proteins (BSA, gelatin-type B 75 bloom, α-amylase, and hGH) and polycations (protamine, polyethylenimine, poly-l-lysine, and poly-l-arginine (PLA)) via an electrostatic interaction and loaded the PECs into the hydrogels. The formations of PECs were affected by molecular weight, pI (or pK(a)), and types of amine group of the used polycations. Unlike other polycations, PLA formed a large uniform complex with BSA, and the PLA/protein complex-loaded hydrogel showed the slowest protein release behavior. In the PEC-loaded hydrogel system, the protein release could also be controlled by viscosities of the gel and weight ratios of polycations and proteins, although the activities of the proteins were decreased in proportion to the PLA amounts. These results suggest that the PEC-loaded injectable and thermosensitive poly(organophosphazene) hydrogel has considerable potential for creating a sustained protein delivery system by using the PEC via electrostatic interaction. Copyright © 2010 Elsevier B.V. All rights reserved.

  11. Primary Cultures of Glomerular Parietal Epithelial Cells or Podocytes with Proven Origin

    PubMed Central

    Schulte, Kevin; Sechi, Antonio; Sauer-Lehnen, Sibille; Tag, Carmen; Boor, Peter; Kuppe, Christoph; Warsow, Gregor; Schordan, Sandra; Mostertz, Jörg; Chilukoti, Ravi Kumar; Homuth, Georg; Endlich, Nicole; Tacke, Frank; Weiskirchen, Ralf; Fuellen, Georg; Endlich, Karlhans; Floege, Jürgen; Smeets, Bart; Moeller, Marcus J.

    2012-01-01

    Parietal epithelial cells (PECs) are crucially involved in the pathogenesis of rapidly progressive glomerulonephritis (RPGN) as well as in focal and segmental glomerulosclerosis (FSGS). In this study, transgenic mouse lines were used to isolate pure, genetically tagged primary cultures of PECs or podocytes using FACsorting. By this approach, the morphology of primary glomerular epithelial cells in culture could be resolved: Primary podocytes formed either large cells with intracytoplasmatic extensions or smaller spindle shaped cells, depending on specific culture conditions. Primary PECs were small and exhibited a spindle-shaped or polygonal morphology. In the very early phases of primary culture, rapid changes in gene expression (e.g. of WT-1 and Pax-2) were observed. However, after prolonged culture primary PECs and podocytes still segregated clearly in a transcriptome analysis - demonstrating that the origin of primary cell cultures is important. Of the classical markers, synaptopodin and podoplanin expression were differentially regulated the most in primary PEC and podocyte cultures. However, no expression of any endogenous gene allowed to differentiate between the two cell types in culture. Finally, we show that the transcription factor WT1 is also expressed by PECs. In summary, genetic tagging of PECs and podocytes is a novel and necessary tool to derive pure primary cultures with proven origin. These cultures will be a powerful tool for the emerging field of parietal epithelial cell biology. PMID:22529955

  12. Silicon/Organic Heterojunction for Photoelectrochemical Energy Conversion Photoanode with a Record Photovoltage.

    PubMed

    Cui, Wei; Wu, Shan; Chen, Fengjiao; Xia, Zhouhui; Li, Yanguang; Zhang, Xiao-Hong; Song, Tao; Lee, Shuit-Tong; Sun, Baoquan

    2016-09-20

    Silicon (Si) is a good photon absorption material for photoelectrochemical (PEC) conversion. Recently, the relatively low photovoltage of Si-based PEC anode is one of the most significant factors limiting its performance. To achieve a high photovoltage in PEC electrode, both a large barrier height and high-quality surface passivation of Si are indispensable. However, it is still challenging to induce a large band bending and passivate Si surface simultaneously in Si-based PEC photoanodes so far, which hinders their performance. Here, we develop a simple Si/poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) heterojunction with large band banding and excellent surface passiviation for efficient PEC conversion. A chemically modified PEDOT:PSS film acts as both a surface passiviation layer and an effective catalyst simultaneously without sacrificing band bending level. A record photovoltage for Si-based PEC photoanodes as high as 657 mV is achieved via optimizing the PEDOT:PSS film fabrication process. The density of electron state (DOS) measurement is utilized to probe the passivation quality of the organic/inorganic heterojunction, and a low DOS is found in the Si/PEDOT:PSS heterojunction, which is in accordance with the photovoltage results. The low-temperature solution-processed Si/organic heterojunction photoanode provides a high photovoltage, exhibiting the potential to be the next-generation economical photoanode in PEC applications.

  13. Escherichia coli virulence genes profile of surface waters as an indicator of water quality.

    PubMed

    Masters, N; Wiegand, A; Ahmed, W; Katouli, M

    2011-12-01

    We compared the presence of 58 known virulence genes (VGs) associated with Escherichia coli strains causing intestinal (InPEC) and extra-intestinal (ExPEC) infections in three estuarine, four brackish and 13 freshwater sites during the dry and wet seasons. The most common VGs observed in water samples during the dry season belonged to ExPEC (traT; 80% and ompA; 70%) whilst east1 (70%) gene was the most common among InPEC. More types of VGs were observed in water samples during wet season and included those found among InPEC (e.g. eaeA; 100%; fyuA, 90%; paa, 65%; cdt, 60%; and stx(2), 60%) and ExPEC (e.g. iroN(E.coli), 90%; iss, 90% and kpsMTII, 80%). Eight VGs were found exclusively in the wet season, of which four were found in all three water types indicating their association with storm-water run off. The number of VGs associated with ExPEC were significantly (P < 0.05) higher in only brackish and estuarine waters during the wet season compared to the dry season. There was no correlation between the number of E. coli and the presence of VGs in any of the water types in both seasons but we found similarities in VG profiles of sites with similar land uses.

  14. Photoelectrochemical Carbon Dioxide Reduction Using a Nanoporous Ag Cathode.

    PubMed

    Zhang, Yan; Luc, Wesley; Hutchings, Gregory S; Jiao, Feng

    2016-09-21

    Solar fuel production from abundant sources using photoelectrochemical (PEC) systems is an attractive approach to address the challenges associated with the intermittence of solar energy. In comparison to electrochemical systems, PEC cells directly utilize solar energy as the energy input, and if necessary, then an additional external bias can be applied to drive the desired reaction. In this work, a PEC cell composing of a Ni-coated Si photoanode and a nanoporous Ag cathode was developed for CO2 conversion to CO. The thin Ni layer not only protected the Si wafer from photocorrosion but also served as the oxygen evolution catalyst. At an external bias of 2.0 V, the PEC cell delivered a current density of 10 mA cm(-2) with a CO Faradaic efficiency of ∼70%. More importantly, a stable performance up to 3 h was achieved under photoelectrolysis conditions, which is among the best literature-reported performances for PEC CO2 reduction cells. The photovoltage of the PEC cell was estimated to be ∼0.4 V, which corresponded to a 17% energy saving by solar energy utilization. Postreaction structural analysis showed the corrosion of the Ni layer at the Si photoanode/catalyst interface, which caused performance degradation under prolonged operations. A stable oxygen evolution catalyst with a robust interface is crucial to the long-term stability of PEC CO2 reduction cells.

  15. The Ins and Outs of siderophore mediated iron uptake by extra-intestinal pathogenic Escherichia coli.

    PubMed

    Garénaux, Amélie; Caza, Mélissa; Dozois, Charles M

    2011-11-21

    Extraintestinal pathogenic E. coli (ExPEC) are responsible for many infectious diseases in livestock, such as airsacculitis in poultry, acute mastitis in dairy animals and neonatal septicaemia and urinary tract infections (UTI) in pigs and cattle. In their animal hosts, ExPEC have to cope with low iron availability. By using different strategies, ExPEC strains are able to retrieve iron sequestered by host proteins. One of these strategies is the use of siderophores, which are small secreted molecules with high affinity for iron. ExPEC are known to synthesize up to four different types of siderophores: enterobactin, salmochelins, yersiniabactin and aerobactin. Steps required for iron acquisition by siderophores include (1) siderophore synthesis in the cytoplasm, (2) siderophore secretion, (3) ferri-siderophore reception, (4) ferri-siderophore internalization and (5) iron release in the cytoplasm. Each siderophore has specific properties and may be differentially regulated to provide different advantages, potentially allowing ExPEC to adapt to different environmental conditions or to overcome host innate immunity. Iron acquisition by siderophores plays a significant role in ExPEC virulence and, as it requires outer membrane receptors, it constitutes an interesting target for the development of vaccines that could be used to limit the number of infectious diseases due to ExPEC in livestock.

  16. Structured performance assessment in three pediatric emergency scenarios: a validation study.

    PubMed

    Schmutz, Jan; Manser, Tanja; Keil, Julia; Heimberg, Ellen; Hoffmann, Florian

    2015-06-01

    To develop and validate 3 performance evaluation checklists (PECs) for systematic performance assessment in 3 clinical scenarios: cardiopulmonary arrest, dyspnea with oxygen desaturation after intubation, and respiratory syncytial virus (RSV). The 3 PECs were developed using an integrative approach and used to rate 50 training sessions in a simulator environment by different raters. Construct validity was tested by correlating the checklist scores with external constructs (ie, global rating, team experience level, and time to action). Further interrater reliability was tested for all 3 PECs. The PECs for the desaturation and cardiopulmonary arrest scenarios were valid and reliable, whereas the PEC for RSV had limited validity and reliability. For 2 pediatric emergencies, the PEC is a valid and reliable tool for systematic performance assessment. The unsatisfactory results for the PEC for RSV may be related to limitations of the simulation setting and require further investigation. Structured assessment of clinical performance can augment feedback on technical performance aspects and is essential for training purposes as well as for research. Only reliable and valid performance measures will allow medical educators to accurately evaluate the behavioral effects of training interventions and further enhance the quality of patient care. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Use of Zebrafish to Probe the Divergent Virulence Potentials and Toxin Requirements of Extraintestinal Pathogenic Escherichia coli

    PubMed Central

    Wiles, Travis J.; Bower, Jean M.; Redd, Michael J.; Mulvey, Matthew A.

    2009-01-01

    Extraintestinal pathogenic E. coli (ExPEC) cause an array of diseases, including sepsis, neonatal meningitis, and urinary tract infections. Many putative virulence factors that might modulate ExPEC pathogenesis have been identified through sequencing efforts, epidemiology, and gene expression profiling, but few of these genes have been assigned clearly defined functional roles during infection. Using zebrafish embryos as surrogate hosts, we have developed a model system with the ability to resolve diverse virulence phenotypes and niche-specific restrictions among closely related ExPEC isolates during either localized or systemic infections. In side-by-side comparisons of prototypic ExPEC isolates, we observed an unexpectedly high degree of phenotypic diversity that is not readily apparent using more traditional animal hosts. In particular, the capacity of different ExPEC isolates to persist and multiply within the zebrafish host and cause disease was shown to be variably dependent upon two secreted toxins, α-hemolysin and cytotoxic necrotizing factor. Both of these toxins appear to function primarily in the neutralization of phagocytes, which are recruited in high numbers to sites of infection where they act as an essential host defense against ExPEC as well as less virulent E. coli strains. These results establish zebrafish as a valuable tool for the elucidation and functional analysis of both ExPEC virulence factors and host defense mechanisms. PMID:20019794

  18. Evaluation of the MPN, Anderson-Baird-Parker, Petrifilm E. coli and Fluorocult ECD method for enumeration of Escherichia coli in foods of animal origin.

    PubMed

    Bredie, W L; de Boer, E

    1992-07-01

    Commercially available beta-D-glucuronidase (GUR) based methods, Petrifilm E. coli (PEC) and Fluorocult ECD (FECD), and ISO standard MPN and Anderson-Baird-Parker (ABP) procedures were evaluated for routine enumeration of E. coli in naturally contaminated foods of animal origin. The methods concerned were classifiable in a sequence of best qualities for: production, MPN > ABP = PEC = FECD; costs, FECD > ABP = PEC > MPN; time per measurement, ABP = PEC = FECD > MPN; practical use, PEC > FECD > ABP > MPN; detection at low contamination, MPN > ABP = PEC > FECD. The ABP and PEC method appeared useful for routine counting of E. coli in raw meat, poultry and meat products, whereas the MPN procedure turned out to be more sensitive, however, impractical and considerably more expensive. The FECD method was inexpensive although suitable for the enumeration of E. coli at higher contamination level (> 50 cfu/g). The indole and MUG indicators both applied to demonstrate E. coli with the ABP or FECD method proved to be equal in specificity.

  19. Dietary zinc and BCG injection influence macrophage function

    SciTech Connect

    Briske-Anderson, M.J.; Kramer, T.R.

    1986-03-05

    Weanling male Lewis rats were fed ad-libitum for 21-25 days a diet based on AIN standards containing 20% egg-white protein and deficient (2 ..mu..g/g) or adequate (20 ..mu..g/g) zinc. A pair-fed (PF) group was fed a Zn-adequate diet, equal to the amount consumed by Zn-deficient rats. Zn-deficient rats exhibited typical signs of Zn deficiency. Seven days prior to completion of dietary regimen rats from each group (N=10) were injected in the forelimb footpads with 250 ..mu..g of BCG (Cell wall skeleton of bacille Calmette Guerin) in Incomplete Freund's Adjuvant (IFA), or with IFA alone. Three days prior to completion of dietary regimen rats from each group were injected intraperitoneally with sterile paraffin oil. Upon completion of dietary regimen peritoneal exudate cells (PEC) were collected. Equivalent phagocytic activity (chemiluminescence) was exhibited by PEC from Zn-deficient and PF rats injected with BCG or IFA, and by PEC from Zn-adequate rats injected with IFA. Phagocytic activity by PEC of BCG injected Zn-adequate rats was significantly higher than in PEC of the other groups. PEC from BCG injected Zn-adequate, Zn-deficient and PF rats, however, equivalently suppressed the proliferation of Con-A stimulated SLC from control (noninjected, Zn-adequate) rats. The findings suggest that PEC of BCG injected Zn-adequate rats produce elevated hydrogen peroxide and hydroxyl radicals.

  20. Chitosan/pectin/gum Arabic polyelectrolyte complex: process-dependent appearance, microstructure analysis and its application.

    PubMed

    Tsai, Ruei-Yi; Chen, Pin-Wen; Kuo, Ting-Yun; Lin, Che-Min; Wang, Da-Ming; Hsien, Tzu-Yang; Hsieh, Hsyue-Jen

    2014-01-30

    Novel chitosan/pectin/gum Arabic polyelectrolyte complex (PEC) solutions and membranes with various compositions were prepared for biomedical applications. The appearance of the PEC solutions, either clear or turbid, was process-dependent and depended on how the three components were dissolved and mixed. The addition of gum Arabic to the chitosan and pectin significantly decreased the viscosities of the resultant PEC solutions due to the formation of globe-like microstructures that was accompanied by network-like microstructures and other molecular entanglements. The mechanical strength and hydrophilicity of the PEC membranes manufactured from the PEC solutions, especially for a weight ratio of 84/8/8 (chitosan/pectin/gum Arabic), were enhanced compared to pure chitosan membranes. Moreover, the use of the 84/8/8 PEC membranes as a drug carrier exhibited steady and fairly complete release of a drug (insulin) for 6h. Based on these promising results, the chitosan/pectin/gum Arabic PEC membranes have great potential in controlled drug release applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Local and systemic delivery of VEGF siRNA using polyelectrolyte complex micelles for effective treatment of cancer.

    PubMed

    Kim, Sun Hwa; Jeong, Ji Hoon; Lee, Soo Hyeon; Kim, Sung Wan; Park, Tae Gwan

    2008-07-14

    For efficient cancer therapy, small interfering RNA (siRNA) should be stably and efficiently delivered into the target tissue and readily taken up by cancer cells. To address these needs, a polyelectrolyte complex (PEC) micelle-based siRNA delivery system was developed for anti-angiogenic gene therapy. The interaction between poly(ethylene glycol) (PEG)-conjugated vascular endothelial growth factor siRNA (VEGF siRNA-PEG) and polyethylenimine (PEI) led to the spontaneous formation of nanoscale polyelectrolyte complex micelles (VEGF siRNA-PEG/PEI PEC micelles), having a characteristic siRNA/PEI PEC inner core with a surrounding PEG shell layer. Intravenous as well as intratumoral administration of the PEC micelles significantly inhibited VEGF expression at the tumor tissue and suppressed tumor growth in an animal tumor model without showing any detectable inflammatory responses in mice. Upon examination of the PEC micelle distribution and in vivo optical imaging following intravenously injection, enhanced accumulation of the PEC micelles was also observed in the tumor region. This study demonstrates the feasibility of using PEC micelles as a potential carrier for therapeutic siRNAs in local and systemic treatment of cancer.

  2. Tissue factor and tissue factor pathway inhibitor in women with a past history of preeclampsia: implication for a hypercoagulable state postpregnancy.

    PubMed

    Lwaleed, Bashir A; Breish, Mohamed O; Birch, Brian R; Chowdhary, Azeem P; Saad, Rasheed A; Perigo, Oliver; Kazmi, Rashid S; Dusse, Luci M; Cooper, Alan J

    2014-10-01

    Preeclampsia (P-EC) is a multisystem disorder of pregnancy whose cause and pathogenesis remain poorly understood. However, abnormal haemostasis and endothelial dysfunction are thought to be implicated. Women with a past medical history of P-EC have a baseline hypercoagulable state postpregnancy. The aim of this study is to examine the relationship between tissue factor (TF) and TF pathway inhibitor (TFPI) in women who have had P-EC within the last 3 years (more than 6 months postpartum) and their normal counterparts. Blood specimens were collected from women known to have had P-EC within the last 3 years (n = 26) and aged-matched healthy women without past history of P-EC in previous pregnancy (n = 26). Plasma TF and TFPI levels were measured using ELISAs. Women who have had P-EC showed increased TF levels compared with their normal counterparts, whereas TFPI levels were reduced. Neither parameter differed significantly when the groups were tested against each other. Interestingly, the TF/TFPI ratio was significantly increased (P = 0.024) when the two groups were compared. In summary, there was a trend towards increased TF and reduced TFPI levels in the P-EC group. Such a tendency was not statistically significant. However, the TF/TFPI ratio was significantly increased when the groups were compared. Our findings suggest an imbalance between TF/TFPI levels in women with past history of P-EC postpregnancy. This may contribute to the development of maternal hypercoagulable states and may predispose women with a history of P-EC to cardiovascular risks later in life.

  3. The Department of Defense pharmacy benefit management program.

    PubMed

    Ridderhoff, Kevin; Remund, Daniel

    2005-04-01

    Prescription drug prices are frequently both politically and personally salient issues. The Department of Defense (DoD) offers a robust prescription benefit to 8.8 million beneficiaries. This benefit has evolved to meet changes in technology and patient requirements. The PharmacoEconomic Center (PEC) was established as the first pharmacy benefit manager entity in 1992, primarily in response to rapidly rising DoD pharmacy program expenditures. In its short history, the PEC has dramatically improved patient safety and decreased costs. To accelerate the efficiency and effectiveness the enterprise-wide pharmacy benefit manager has already achieved, DoD should increase the funding, staff, and authority of the PEC.

  4. A study of potential energy curves from the model space quantum Monte Carlo method

    SciTech Connect

    Ohtsuka, Yuhki; Ten-no, Seiichiro

    2015-12-07

    We report on the first application of the model space quantum Monte Carlo (MSQMC) to potential energy curves (PECs) for the excited states of C{sub 2}, N{sub 2}, and O{sub 2} to validate the applicability of the method. A parallel MSQMC code is implemented with the initiator approximation to enable efficient sampling. The PECs of MSQMC for various excited and ionized states are compared with those from the Rydberg-Klein-Rees and full configuration interaction methods. The results indicate the usefulness of MSQMC for precise PECs in a wide range obviating problems concerning quasi-degeneracy.

  5. PULSED EDDY CURRENT THICKNESS MEASUREMENT OF SELECTIVE PHASE CORROSION ON NICKEL ALUMINUM BRONZE VALVES

    SciTech Connect

    Krause, T. W.; Harlley, D.; Babbar, V. K.; Wannamaker, K.

    2010-02-22

    Nickel Aluminum Bronze (NAB) is a material with marine environment applications that under certain conditions can undergo selective phase corrosion (SPC). SPC involves the removal of minority elements while leaving behind a copper matrix. Pulsed eddy current (PEC) was evaluated for determination of SPC thickness on a NAB valve section with access from the surface corroded side. A primarily linear response of PEC amplitude, up to the maximum available SPC thickness of 4 mm was observed. The combination of reduced conductivity and permeability in the SPC phase relative to the base NAB was used to explain the observed sensitivity of PEC to SPC thickness variations.

  6. Enhancement in hydrogen evolution using Au-TiO2 hollow spheres with microbial devices modified with conjugated oligoelectrolytes.

    PubMed

    Ngaw, Chee Keong; Wang, Victor Bochuan; Liu, Zhengyi; Zhou, Yi; Kjelleberg, Staffan; Zhang, Qichun; Tan, Timothy Thatt Yang; Loo, Say Chye Joachim

    2015-01-01

    Although photoelectrochemical (PEC) water splitting heralds the emergence of the hydrogen economy, the need for external bias and low efficiency stymies the widespread application of this technology. By coupling water splitting (in a PEC cell) to a microbial fuel cell (MFC) using Escherichia coli as the biocatalyst, this work aims to successfully demonstrate a sustainable hybrid PEC-MFC platform functioning solely by biocatalysis and solar energy, at zero bias. Through further chemical modification of the photo-anode (in the PEC cell) and biofilm (in the MFC), the performance of the hybrid system is expected to improve in terms of the photocurrent generated and hydrogen evolved. The hybrid system constitutes the interconnected PEC cell with the MFC. Both PEC cell and MFC are typical two-chambered systems housing the anode and cathode. Au-TiO2 hollow spheres and conjugated oligoelectrolytes were synthesised chemically and introduced to the PEC cell and MFC, respectively. Hydrogen evolution measurements were performed in triplicates. The hybrid PEC-MFC platform generated a photocurrent density of 0.35 mA/cm(2) (~70× enhancement) as compared with the stand-alone P25 standard PEC cell (0.005 mA/cm(2)) under one-sun illumination (100 mW/cm(2)) at zero bias (0 V vs. Pt). This increase in photocurrent density was accompanied by continuous H2 production. No H2 was observed in the P25 standard PEC cell whereas H2 evolution rate was ~3.4 μmol/h in the hybrid system. The remarkable performance is attributed to the chemical modification of E. coli through the incorporation of novel conjugated oligoelectrolytes in the MFC as well as the lower recombination rate and higher photoabsorption capabilities in the Au-TiO2 hollow spheres electrode. The combined strategy of photo-anode modification in PEC cells and chemically modified MFCs shows great promise for future exploitation of such synergistic effects between MFCs and semiconductor-based PEC water splitting.

  7. Brief report: increasing communication skills for an elementary-aged student with autism using the Picture Exchange Communication System.

    PubMed

    Kravits, Tamara R; Kamps, Debra M; Kemmerer, Katie; Potucek, Jessica

    2002-06-01

    The purpose of this study was to examine the effects of the Picture Exchange Communication System (PECS) on the spontaneous communication skills of a 6-year-old girl with autism across her home and school environments. The effects of the PECS were also examined for social interaction. Results indicated increases in spontaneous language (i.e., requests and comments) including use of the icons and verbalizations across those settings in which PECS was implemented. Intelligible verbalizations increased in two of three settings, and changes in peer social interaction were noted in one of the two school settings.

  8. Design and engineering of disulfide crosslinked nanocomplexes of polyamide polyelectrolytes: stability under biorelevant conditions and potent cellular internalization of entrapped model peptide.

    PubMed

    Sharma, Aashish; Kundu, Somanath; Reddy M, Amarendar; Bajaj, Avinash; Srivastava, Aasheesh

    2013-07-01

    Counter polyelectrolytes (PEs) having a degradable polyamide backbone and controlled thiolation are prepared. Their nanosized polyelectrolyte complexes (PECs) spontaneously crosslink under ambient conditions via bioreducible disulfide bonds. These PECs are regenerable after centrifugation, and resist degradation by proteases. They are stable to variations of pH and electrolyte concentration, similar to those encountered in biological milieu. However, they are unraveled in reductive conditions. These PECs act as efficient vectors for delivering entrapped cargo. They entrap with high efficiency, and controllably release, fluorescein isothiocyanate (FITC)-insulin (a model peptide) in vitro. Potent cellular internalization of FITC-insulin within human lung cancer cells with high cell viability is demonstrated.

  9. Characterization of extraintestinal pathogenic Escherichia coli isolated from captive wild felids with bacteremia.

    PubMed

    Carvalho, Vania M; Osugui, Lika; Setzer, Ariela P; Lopez, Rodrigo P G; Pestana de Castro, Antonio F; Irino, Kinue; Catão-Dias, José L

    2012-09-01

    Diseases caused by extraintestinal pathogenic Escherichia coli (ExPEC) in wild felids are rarely reported. Although urinary tract infections are infrequently reported in domestic cats, such infections when present are commonly caused by ExPEC. The present work characterized ExPEC strains isolated from 2 adult felines, a snow leopard (Panthera uncia) and a black leopard (Panthera pardus melas), that died from secondary bacteremia associated with urinary tract infections. Isolates from both animals were classified into the B2 phylogenetic group and expressed virulence genotypes that allowed them to cause severe disease. In addition, strains from the black leopard showed multidrug resistance.

  10. Hybrid heterojunction and photoelectrochemistry solar cell based on silicon nanowires and double-walled carbon nanotubes.

    PubMed

    Shu, Qinke; Wei, Jinquan; Wang, Kunlin; Zhu, Hongwei; Li, Zhen; Jia, Yi; Gui, Xuchun; Guo, Ning; Li, Xinming; Ma, Chaoran; Wu, Dehai

    2009-12-01

    A hybrid solar cell model composed of a heterojunction cell and a photoelectrochemical (PEC) cell has been proposed and characterized. In the hybrid cell, a thin film of double-walled carbon nanotubes forms a heterojunction with the silicon nanowire (SiNW) array and also functions as the transparent counter electrode of the PEC cell. The cell performance can be readily tuned by controlling the SiNW density. Under AM 1.5G illumination, a power conversion efficiency of 1.29%, higher than those reported for SiNW array-based PEC cells, has been obtained.

  11. Electricity generation and pollutant degradation using a novel biocathode coupled photoelectrochemical cell.

    PubMed

    Du, Yue; Feng, Yujie; Qu, Youpeng; Liu, Jia; Ren, Nanqi; Liu, Hong

    2014-07-01

    The photoelectrochemical cell (PEC) is a promising tool for the degradation of organic pollutants and simultaneous electricity recovery, however, current cathode catalysts suffer from high costs and short service lives. Herein, we present a novel biocathode coupled PEC (Bio-PEC) integrating the advantages of photocatalytic anode and biocathode. Electrochemical anodized TiO2 nanotube arrays fabricated on Ti substrate were used as Bio-PEC anodes. Field-emission scanning electron microscope images revealed that the well-aligned TiO2 nanotubes had inner diameters of 60-100 nm and wall-thicknesses of about 5 nm. Linear sweep voltammetry presented the pronounced photocurrent output (325 μA/cm(2)) under xenon illumination, compared with that under dark conditions. Comparing studies were carried out between the Bio-PEC and PECs with Pt/C cathodes. The results showed that the performance of Pt/C cathodes was closely related with the structure and Pt/C loading amounts of cathodes, while the Bio-PEC achieved similar methyl orange (MO) decoloration rate (0.0120 min(-1)) and maximum power density (211.32 mW/m(2)) to the brush cathode PEC with 50 mg Pt/C loading (Brush-PEC, 50 mg). The fill factors of Bio-PEC and Brush-PEC (50 mg) were 39.87% and 43.06%, respectively. The charge transfer resistance of biocathode was 13.10 Ω, larger than the brush cathode with 50 mg Pt/C (10.68 Ω), but smaller than the brush cathode with 35 mg Pt/C (18.35 Ω), indicating the comparable catalytic activity with Pt/C catalyst. The biocathode was more dependent on the nutrient diffusion, such as nitrogen and inorganic carbon, thus resulting in relatively higher diffusion resistance compared to the brush cathode with 50 mg Pt/C loading that yielded similar MO removal and power output. Considering the performance and cost of PEC system, the biocathode was a promising alternative for the Pt/C catalyst.

  12. High-performance photoelectrochemical cells based on a binuclear ruthenium catalyst for visible-light-driven water oxidation.

    PubMed

    Zhang, Linlin; Gao, Yan; Ding, Xin; Yu, Ze; Sun, Licheng

    2014-10-01

    Two photoanodes based on a binuclear (2) and a mononuclear ruthenium (3) water oxidation catalysts were assembled in combination with a molecular photosensitizer (1) by using a co-adsorption method. The anodes were used in dye-sensitized photoelectrochemical cells (DS-PECs) for visible-light-driven water splitting. A DS-PEC device using TiO2 (1+2) as working electrode (WE) exhibits better performance than TiO2 (1+3) as WE in light-driven water splitting. Detailed photoelectrochemical studies on these DS-PEC devices are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Lattice defect-enhanced hydrogen production in nanostructured hematite-based photoelectrochemical device.

    PubMed

    Wang, Peng; Wang, Degao; Lin, Jun; Li, Xiaolong; Peng, Cheng; Gao, Xingyu; Huang, Qing; Wang, Jianqiang; Xu, Hongjie; Fan, Chunhai

    2012-04-01

    Nanostructured hematite photoanodes have been intensively studied in photoelectrochemical (PEC) water splitting for sustainable hydrogen production. Whereas many previous efforts have been focused on doping elements in nanostructured hematite (α-Fe(2)O(3)), we herein demonstrated an alternative approach to enhance the PEC performance by exploiting intrinsic nanostructuring properties of hematite. We found that the introduction of lattice defects effectively decreased the flatband potential and increased the charge transport mobility of nanostructured hematite, hence enhance the light harvest for more efficient hydrogen production via PEC. The nanostructured hematite photoanodes with lattice defects yielded water-splitting photocurrent density of 1.2 mA/cm(2) at 1.6 V vs reversible hydrogen electrode (RHE), which excelled defect-free ones by approximately 1.5 folds. This study thus provides a new strategy for finely tuning properties of nanostructured hematite photoanodes and enhancing the water-splitting ability of PEC.

  14. Contrast enhanced exposure strategy in multi-beam mask writing

    NASA Astrophysics Data System (ADS)

    Belic, Nikola; Hofmann, Ulrich; Klikovits, Jan; Martens, Stephan

    2013-03-01

    Since multi electron beam exposure has become a serious contender for next generation mask making, proximity- and process effect corrections (PEC) need to be adapted to this technology. With feature sizes in the order of the short-range blurs (resist and tool), contrast enhancements need to be combined with standard linearity corrections. Different PEC strategies are reviewed and compared with respect to their suitability for multi-beam exposure. This analysis recommends a hybrid approach that combines the benefits of shape- and dose PEC and is optimally applicable for multibeam exposure. Exposure results on the proof-of-concept 50keV electron multi-beam mask exposure tool (eMET POC) and a standard 50 kV vector shaped beam tool (VSB) are shown to verify that the combined PEC with overdose contrast enhancement covers the whole pattern range from isolated to opaque.

  15. Pediatric training in emergency medicine residency programs.

    PubMed

    Ludwig, S; Fleisher, G; Henretig, F; Ruddy, R

    1982-04-01

    Endorsed emergency medicine (EM) residency programs were surveyed as to the nature and extent of training they provided in pediatric emergency care (PEC). In the surveys returned (82%) there were several important findings. The amount of time in PEC training was generally two months per year of training. This accounted for 16% of training time. However, the volume of pediatric patients was 25% of the overall patient population. There was wide variation in the sites of PEC training. Didactic sessions often did not cover even core topics. The training program directors were equally divided in their satisfaction with this aspect of their programs. Changes were recommended by 80% of the directors. Changes most often suggested were increasing pediatric patient exposure and obtaining PEC specialists as trainers.

  16. Enhanced Photoelectrochemical Performance from Rationally Designed Anatase/Rutile TiO2 Heterostructures.

    PubMed

    Cao, Fengren; Xiong, Jie; Wu, Fangli; Liu, Qiong; Shi, Zhiwei; Yu, Yanhao; Wang, Xudong; Li, Liang

    2016-05-18

    In a photoelectrochemical (PEC) cell for water splitting, the critical issue is charge separation and transport, which is usually completed by designing semiconductor heterojunctions. TiO2 anatase-rutile mixed junctions could largely improve photocatalytic properties, but impairs PEC water splitting performance. We designed and prepared two types of TiO2 heterostructures with the anatase thin film and rutile nanowire phases organized in different sequences. The two types of heterostructures were used as PEC photoanodes for water splitting and demonstrated completely opposite results. Rutile nanowires on anatase film demonstrated enhanced photocurrent density and onset potential, whereas strong negative performance was obtained from anatase film on rutile nanowire structures. The mechanism was investigated by photoresponse, light absorption and reflectance, and electrochemical impedance spectra. This work revealed the significant role of phase sequence in performance gain of anatase-rutile TiO2 heterostructured PEC photoanodes.

  17. Molecular characterization of ESBL-producing Escherichia coli isolates from hospital- and community-acquired infections in NW Mexico.

    PubMed

    Miranda-Romero, Ana Laura; Silva-Sanchez, Jesus; Garza-Ramos, Ulises; Barrios, Humberto; Sánchez-Pérez, Alejandro; Reyna-Flores, Fernando

    2017-01-01

    We investigated the molecular characteristics of ESBL-producing E. coli (ESBL-PEc) isolates from two hospitals and community settings in Ciudad Obregon, Sonora, Mexico. Between 2011 and 2014, thirty-seven ESBL-PEc isolates were collected. The major encoded ESBL was the blaCTX-M-15 gene (97%); followed by 13.5% of the blaSHV-12 gene, and 5.5% encoded the blaTLA-1 gene. The PMQR gene aac(6´)-Ib-cr was detected in 97% of the isolates and the qnrB gene, in one isolate. The ESBL-PEc isolates corresponded to phylogenetic group B2, ST131. Our results highlight the dissemination of ESBL-PEc isolates in northwest Mexico (Ciudad Obregon, Sonora).

  18. Effects on communicative requesting and speech development of the Picture Exchange Communication System in children with characteristics of autism.

    PubMed

    Ganz, Jennifer B; Simpson, Richard L

    2004-08-01

    Few studies on augmentative and alternative communication (AAC) systems have addressed the potential for such systems to impact word utterances in children with autism spectrum disorders (ASD). The Picture Exchange Communication System (PECS) is an AAC system designed specifically to minimize difficulties with communication skills experienced by individuals with ASD. The current study examined the role of PECS in improving the number of words spoken, increasing the complexity and length of phrases, and decreasing the non-word vocalizations of three young children with ASD and developmental delays (DD) with related characteristics. Participants were taught Phases 1-4 of PECS (i.e., picture exchange, increased distance, picture discrimination, and sentence construction). The results indicated that PECS was mastered rapidly by the participants and word utterances increased in number of words and complexity of grammar.

  19. Controlled synthesis of GaN-based nanowires for photoelectrochemical water splitting applications

    NASA Astrophysics Data System (ADS)

    Ebaid, Mohamed; Kang, Jin-Ho; Ryu, Sang-Wan

    2017-01-01

    Photoelectrochemical (PEC) water splitting using semiconductor materials as light absorbers have been extensively studied. Several semiconducting materials have been proposed, such as TiO2, ZnO, and GaN. Because the efficiency of PEC water splitting is dependent on visible light absorption, the ability to tune the bandgap of GaN by alloying with In makes it advantageous over other wide bandgap semiconductors. The fabrication of GaN-based materials with nanoscale geometry offers more merit for their use in PEC water splitting. In this review, we provide an overview of the recent progress made in the synthesis and application of GaN-based nanomaterials in PEC water splitting. The outstanding challenges and the future prospects of this field will also be addressed.

  20. Formation of polyelectrolyte complexes with diethylaminoethyl dextran: charge ratio and molar mass effect.

    PubMed

    Le Cerf, Didier; Pepin, Anne Sophie; Niang, Pape Momar; Cristea, Mariana; Karakasyan-Dia, Carole; Picton, Luc

    2014-11-26

    The formation of polyelectrolyte complexes (PECs) between carboxymethyl pullulan and DEAE Dextran, was investigated, in dilute solution, with emphasis on the effect of charge density (molar ratio or pH) and molar masses. Electrophoretic mobility measurements have evidenced that insoluble PECs (neutral electrophoretic mobility) occurs for charge ratio between 0.6 (excess of polycation) and 1 (stoichiometry usual value) according to the pH. This atypical result is explained by the inaccessibility of some permanent cationic charge when screened by pH dependant cationic ones (due to the Hoffman alkylation). Isothermal titration calorimetry (ITC) indicates an endothermic formation of PEC with a binding constant around 10(5) L mol(-1). Finally asymmetrical flow field flow fractionation coupled on line with static multi angle light scattering (AF4/MALS) evidences soluble PECs with very large average molar masses and size around 100 nm, in agreement with scrambled eggs multi-association between various polyelectrolyte chains.

  1. Photoelectrocatalytic hydrogen generation and simultaneous degradation of organic pollutant via CdSe/TiO2 nanotube arrays

    NASA Astrophysics Data System (ADS)

    Wang, Wenchao; Li, Fang; Zhang, Dieqing; Leung, Dennis Y. C.; Li, Guisheng

    2016-01-01

    CdSe nanoparticles enhanced TiO2 nanotube arrays electrodes (CdSe/TNTAs) were explored as the photoanode for driving the photoelectrocatalytic (PEC) generation of hydrogen and simultaneous degradation of organic pollutants in a PEC system. The evolution hydrogen and the simultaneous degradation of organic pollutants were performed in an electrolytic cell (three electrodes system) under visible-light (λ > 400 nm). Such CdSe/TiO2 based PEC system exhibited both high efficiency of hydrogen generation and effective oxidation of methyl orange (MO). Such high PEC performance of CdSe/TNTAs was attributed to the high dispersity of CdSe nanoparticles on both outside and inside of the pore walls of TiO2 nanotube arrays, the strong combination and heterojunctions between CdSe and TiO2 through Cdsbnd O bonds via electrodeposition with ion-exchange method.

  2. Photoelectrochemical hydrogen production from biomass derivatives and water.

    PubMed

    Lu, Xihong; Xie, Shilei; Yang, Hao; Tong, Yexiang; Ji, Hongbing

    2014-11-21

    Hydrogen, a clean energy carrier with high energy capacity, is a very promising candidate as a primary energy source for the future. Photoelectrochemical (PEC) hydrogen production from renewable biomass derivatives and water is one of the most promising approaches to producing green chemical fuel. Compared to water splitting, hydrogen production from renewable biomass derivatives and water through a PEC process is more efficient from the viewpoint of thermodynamics. Additionally, the carbon dioxide formed can be re-transformed into carbohydrates via photosynthesis in plants. In this review, we focus on the development of photoanodes and systems for PEC hydrogen production from water and renewable biomass derivatives, such as methanol, ethanol, glycerol and sugars. We also discuss the future challenges and opportunities for the design of the state-of-the-art photoanodes and PEC systems for hydrogen production from biomass derivatives and water.

  3. Preparation and biocompatibility of nanohybrid scaffolds by in situ homogeneous formation of nano hydroxyapatite from biopolymer polyelectrolyte complex for bone repair applications.

    PubMed

    Chen, Jingdi; Yu, Qifeng; Zhang, Guodong; Yang, Shen; Wu, Jiulin; Zhang, Qiqing

    2012-05-01

    The achievement of nano distribution for inorganic reinforced filler is a big challenge to three-dimensional porous composite scaffolds. In this paper, a homogeneous nano hydroxyapatite/polyelectrolyte complex (HAP/PEC) hybrid scaffold was developed and investigated. Based on the enhancing properties of the formation of PEC between chitosan and hyaluronic acid, the introduction of nano HAP via in situ crystallization from the PEC achieved nano distribution in the PEC matrix and supplied nano topographies of extracellular environments for the nanohybrid scaffold. The biocompatibility and bioactivity were evaluated by Human bone mesenchymal stem cells (hBMSCs) proliferation (MTT assay), maturation (alkaline phosphatase (ALP) activity) and histological analysis. The in vitro tests show the scaffold is excellent for cell penetration, growth, and proliferation and it is promising for bone repair application.

  4. ZnFe2O4 Nanotapers: Slag Assistant-Growth and Enhanced Photoelectrochemical Efficiency.

    PubMed

    She, Xuefeng; Zhang, Zhuo

    2017-12-01

    In this study, ZnFe2O4 (ZFO) nanotapers are fabricated on the ZnO nanorods (NRs) by recycling rare-earth oxide (REO) slag as the iron source, which thereby exhibits dramatically enhanced photoelectrochemical (PEC) efficiency. Our studies demonstrate that the electron-hole separation and charge migration can be facilitated by the cascade band alignment of ZFO and ZnO and the branched nanotaper structures. Not only the iron source, the slag particles can also act as the passivation layers, leading to improved electron lifetime and significant PEC enhancement. The current study presents a novel REO-slag-modified PEC anode for high-efficiency PEC devices and offers a possibility of recycling industrial waste for renewable energy generation.

  5. Optical materials technology for energy efficiency and solar energy conversion XI: Photovoltaics, photochemistry, and photoelectrochemistry; Proceedings of the Meeting, Toulouse, France, May 19, 21, 1992

    NASA Astrophysics Data System (ADS)

    Hugot-Le Goff, Anne; Granqvist, Claes-Goran; Lampert, Carl M.

    1992-12-01

    The present conference on solar photovoltaic (PV) and photoelectrochemical (PEC) devices discusses charge-carrier photogeneration in organic solar cells, the kinetics of charge-transfer reactions in PEC solar cells, PV devices from II-VI films, the defect pool-gap state distribution in amorphous-Si:H in equilibrium and under photoexcitation, and the second phases in CdS/CuInSe2 solar cells. Also treated are MOCVD of FeS for solar energy conversion, nanostructured TiO2 films, the optical properties of pyrite thin films annealed at different temperatures, the surface modification of CuGaSe2 thin films via PEC methods, organic and inorganic materials for PV and PEC devices, and the synthesis and testing of organic semiconductor solar cells. (No individual items are abstracted in this volume)

  6. Comparative virulence of urinary and bloodstream isolates of extra-intestinal pathogenic Escherichia coli in a Galleria mellonella model.

    PubMed

    Ciesielczuk, Holly; Betts, Jonathon; Phee, Lynnette; Doumith, Michel; Hope, Russell; Woodford, Neil; Wareham, David W

    2015-01-01

    Extra-intestinal pathogenic Escherichia coli (ExPEC) are a significant cause of urinary tract infections and bacteraemia worldwide. Currently no single virulence factor or ExPEC lineage has been identified as the sole contributor to severe extra-intestinal infection and/or urosepsis. Galleria mellonella has recently been established as a simple model for studying the comparative virulence of ExPEC. In this study we investigated the virulence of 40 well-characterized ExPEC strains, in G. mellonella, by measuring mortality (larvae survival), immune recognition/response (melanin production) and cell damage (lactate dehydrogenase production). Although mortality was similar between urinary and bloodstream isolates, it was heightened for community-associated infections, complicated UTIs and urinary-source bacteraemia. Isolates of ST131 and those possessing afa/dra, ompT and serogroup O6 were also associated with heightened virulence.

  7. Control of extraintestinal foodborne pathogens using intervention technologies

    USDA-ARS?s Scientific Manuscript database

    In recent years it has become apparent that emerging foodborne pathogens including Extraintestinal Pathogenic Escherichia coli (ExPEC), Staphylococcus saprophyticus, and Klebsiella pneumoniae are associated with human health conditions such as inflammatory bowel disease (IBD), ulcerative colitis (UC...

  8. Electrochemiluminescence induced photoelectrochemistry for sensing of the DNA based on DNA-linked CdS NPs superstructure with intercalator molecules.

    PubMed

    Guo, Yingshu; Sun, Yuanshun; Zhang, Shusheng

    2011-02-07

    A novel detection protocol of DNA was developed using electrochemiluminescence (ECL) induced photoelectrochemistry (PEC) synthesis based on DNA-linked CdS NPs superstructure with methylene blue as the intercalator molecule.

  9. Probe exchange catheter used for angioplasty of total coronary artery occlusions.

    PubMed

    Kiemeneij, F; Suwarganda, J S; van der Wieken, L R

    1990-04-01

    Percutaneous transluminal coronary angioplasty (PTCA) for total occlusions frequently fails, because the guidewire fails to pass the occlusion. With the use of the Probe exchange catheter (PEC), however, stiffness of the guidewire is increased and a higher pushability is obtained in order to manipulate the guidewire beyond the lesion. Once the guidewire has passed, the PEC is advanced and a non-over-the-wire dilatation catheter can be introduced through the PEC. This paper describes the technique in a representative case. The results of this technique in 19 consecutive patients with class III-IV/IV(NYHA) angina due to an occluded coronary artery are presented. In 16 patients the PEC reached the lesion (84%) and in all these patients the guidewire could pass the occlusion. A successful PTCA was performed in 14 patients (74%).

  10. Dual role of TiO2 buffer layer in Pt catalyzed BiFeO3 photocathodes: Efficiency enhancement and surface protection

    NASA Astrophysics Data System (ADS)

    Shen, Huanyu; Zhou, Xiaoxue; Dong, Wen; Su, Xiaodong; Fang, Liang; Wu, Xi; Shen, Mingrong

    2017-09-01

    Polycrystalline ferroelectric BiFeO3 (BFO) films deposited on transparent indium tin oxide (ITO) electrodes have shown to be an interesting photocathode for photoelectrochemical (PEC) water splitting; however, its PEC performance and stability are far from perfection. Herein, we reported an amorphous TiO2 buffer layer, inserted between BFO and Pt catalyst, improves significantly both its PEC activity and stability. A photocathodic current density of -460 μA/cm2 at 0 V vs. reversible hydrogen electrode (RHE) and an onset potential of 1.25 V vs. RHE were obtained in ITO/BFO/TiO2/Pt photocathode under 100 mW/cm2 Xe-lamp illumination. TiO2 functions as a buffer layer to remove the upward barrier between BFO and Pt, and makes the photogenerated carriers separate efficiently. The photocathode also shows high stability in acid solution after a 10-h PEC continuous testing.

  11. Phosphorus Cation Doping: A New Strategy for Boosting Photoelectrochemical Performance on TiO2 Nanotube Photonic Crystals.

    PubMed

    Li, Zhenzhen; Xin, Yanmei; Wu, Wenlong; Fu, Baihe; Zhang, Zhonghai

    2016-11-16

    Photoelectrochemical (PEC) water splitting is a promising technique for sustainable hydrogen generation. However, PEC performance on current semiconductors needs further improvement. Herein, a phosphorus cation doping strategy is proposed to fundamentally boost PEC performance on TiO2 nanotube photonic crystal (TiO2 NTPC) photoelectrodes in both the visible-light region and full solar-light illumination. The self-supported P-TiO2 NTPC photoelectrodes are fabricated by a facile two-step electrochemical anodization method and subsequent phosphidation treatment. The Ti(4+) is partially replaced by P cations (P(5+)) from the crystal lattice, which narrows the band gap of TiO2 and induces charge imbalance by the formation of Ti-O-P bonds. We believe the combination of unique photonic nanostructures of TiO2 NTPCs and P cation doping strategy will open up a new opportunity for enhancing PEC performance of TiO2-based photoelectrodes.

  12. Supercritical fluid extraction (SFE) of cranberries does not extract oligomeric proanthocyanidins (PAC) but does alter the chromatography and bioactivity of PAC fractions extracted from SFE residues.

    PubMed

    Feliciano, Rodrigo P; Meudt, Jennifer J; Shanmuganayagam, Dhanansayan; Metzger, Brandon T; Krueger, Christian G; Reed, Jess D

    2014-08-06

    Supercritical fluid extraction (SFE) removed lipophilic compounds and low molecular weight flavonoids from cranberries. However, SFE did not extract proanthocyanidins (PAC). The SFE PAC-enriched residue was submitted to fractionation on Sephadex LH-20 using ethanol, ethanol/methanol, and 80% acetone. PAC degree of polymerization (DP) and ratios of "A-type" to "B-type" interflavan bonds were compared with those of PAC fractions without SFE. Mass spectrometry showed that when SFE was used, PAC distribution was shifted toward higher DP and contained higher amounts of two and three "A-type" bonds compared to PAC fractions without SFE. The 80% acetone fraction with SFE had significantly greater extraintestinal pathogenic Escherichia coli (ExPEC) agglutination and significantly lower ExPEC invasion of enterocytes than the fraction without SFE. Cranberry PAC with higher numbers of "A-type" interflavan bonds are more bioactive in agglutinating ExPEC and inhibiting ExPEC enterocyte invasion.

  13. Chicken as reservoir for extraintestinal pathogenic Escherichia coli in humans, Canada.

    PubMed

    Bergeron, Catherine Racicot; Prussing, Catharine; Boerlin, Patrick; Daignault, Danielle; Dutil, Lucie; Reid-Smith, Richard J; Zhanel, George G; Manges, Amee R

    2012-03-01

    We previously described how retail meat, particularly chicken, might be a reservoir for extraintestinal pathogenic Escherichia coli (ExPEC) causing urinary tract infections (UTIs) in humans. To rule out retail beef and pork as potential reservoirs, we tested 320 additional E. coli isolates from these meats. Isolates from beef and pork were significantly less likely than those from chicken to be genetically related to isolates from humans with UTIs. We then tested whether the reservoir for ExPEC in humans could be food animals themselves by comparing geographically and temporally matched E. coli isolates from 475 humans with UTIs and from cecal contents of 349 slaughtered animals. We found genetic similarities between E. coli from animals in abattoirs, principally chickens, and ExPEC causing UTIs in humans. ExPEC transmission from food animals could be responsible for human infections, and chickens are the most probable reservoir.

  14. Chicken as Reservoir for Extraintestinal Pathogenic Escherichia coli in Humans, Canada

    PubMed Central

    Bergeron, Catherine Racicot; Prussing, Catharine; Boerlin, Patrick; Daignault, Danielle; Dutil, Lucie; Reid-Smith, Richard J.; Zhanel, George G.

    2012-01-01

    We previously described how retail meat, particularly chicken, might be a reservoir for extraintestinal pathogenic Escherichia coli (ExPEC) causing urinary tract infections (UTIs) in humans. To rule out retail beef and pork as potential reservoirs, we tested 320 additional E. coli isolates from these meats. Isolates from beef and pork were significantly less likely than those from chicken to be genetically related to isolates from humans with UTIs. We then tested whether the reservoir for ExPEC in humans could be food animals themselves by comparing geographically and temporally matched E. coli isolates from 475 humans with UTIs and from cecal contents of 349 slaughtered animals. We found genetic similarities between E. coli from animals in abattoirs, principally chickens, and ExPEC causing UTIs in humans. ExPEC transmission from food animals could be responsible for human infections, and chickens are the most probable reservoir. PMID:22377351

  15. Preeclampsia as a risk factor for diabetes: a population-based cohort study.

    PubMed

    Feig, Denice S; Shah, Baiju R; Lipscombe, Lorraine L; Wu, C Fangyun; Ray, Joel G; Lowe, Julia; Hwee, Jeremiah; Booth, Gillian L

    2013-01-01

    Women with preeclampsia (PEC) and gestational hypertension (GH) exhibit insulin resistance during pregnancy, independent of obesity and glucose intolerance. Our aim was to determine whether women with PEC or GH during pregnancy have an increased risk of developing diabetes after pregnancy, and whether the presence of PEC/GH in addition to gestational diabetes (GDM) increases the risk of future (postpartum) diabetes. We performed a population-based, retrospective cohort study for 1,010,068 pregnant women who delivered in Ontario, Canada between April 1994 and March 2008. Women were categorized as having PEC alone (n=22,933), GH alone (n=27,605), GDM alone (n=30,852), GDM+PEC (n=1,476), GDM+GH (n=2,100), or none of these conditions (n=925,102). Our main outcome was a new diagnosis of diabetes postpartum in the following years, up until March 2011, based on new records in the Ontario Diabetes Database. The incidence rate of diabetes per 1,000 person-years was 6.47 for women with PEC and 5.26 for GH compared with 2.81 in women with neither of these conditions. In the multivariable analysis, both PEC alone (hazard ratio [HR]=2.08; 95% CI 1.97-2.19) and GH alone (HR=1.95; 95% CI 1.83-2.07) were risk factors for subsequent diabetes. Women with GDM alone were at elevated risk of developing diabetes postpartum (HR=12.77; 95% CI 12.44-13.10); however, the co-presence of PEC or GH in addition to GDM further elevated this risk (HR=15.75; 95% CI 14.52-17.07, and HR=18.49; 95% CI 17.12-19.96, respectively). Data on obesity were not available. Women with PEC/GH have a 2-fold increased risk of developing diabetes when followed up to 16.5 years after pregnancy, even in the absence of GDM. The presence of PEC/GH in the setting of GDM also raised the risk of diabetes significantly beyond that seen with GDM alone. A history of PEC/GH during pregnancy should alert clinicians to the need for preventative counseling and more vigilant screening for diabetes. Please see later in the

  16. Cloned human 5-HT1A receptor pharmacology determined using agonist binding and measurement of cAMP accumulation.

    PubMed

    Sharif, Najam A; Drace, Colene D; Williams, Gary W; Crider, Julie Y

    2004-10-01

    Twenty agonists and nine antagonists were evaluated for their ability to compete for [3H]-8-hydroxy-2-(di-n-propylamino)tetralin ([3H]-8-OH-DPAT) binding to the cloned human serotonin-1A (ch-5-HT1A) receptor expressed in Chinese hamster ovary cells and for their ability to alter adenylyl cyclase activity in the same cells. The most potent full agonists of high affinity included N,N-dipropyl-5-carboxamidotryptamine (pEC50=9.6 +/- 0.1), MDL 73005EF (pEC50=9.3 +/- 0.2), 5-methyl-urapidil (pEC50=9.2 +/- 0.1), 5-carboxamidotryptamine (pEC50=9.1 +/- 0.2), R(+)-8-OH-DPAT (pEC50=8.6 +/- 0.1) and BMY-7378 (pEC50=8.6 +/- 0.1). WB-4101 (pEC50=8.3 +/- 0.2; IA=79%), clozapine (pEC50=8.1 +/- 0.3; IA=29%), (buspirone (pEC50=7.6 +/- 0.2; IA=79%), quipazine (pEC50 <5; IA=45%) and R-DOI (pEC50 < 5; IA=31%) were weaker agonists with partial agonist properties. The most potent antagonists were WAY-100,635 (pKi=10.2 +/- 0.1), methiothepin (pKi=8.8 +/- 0.2), spiperone (pKi=8.7 +/- 0.2) and NAN-190 (pKi=8.5 +/- 0.2). The receptor affinities and functional potencies were well correlated (r=0.88; P <0.0001). Our binding data correlated well with the pharmacology of endogenous 5-HT1A receptors in the rabbit iris-ciliary body (r=0.91; P <0.001) and rat hippocampus (r=0.93, P <0.0001). Our functional cAMP data correlated well with other cAMP accumulation data (r=0.8, P <0.01 vs calf hippocampus) but less so with [35S]-GTPgammaS binding to the ch-5-HT(1A) receptor as a functional activity read-out (r=0.58, P <0.05). The present study provides a detailed pharmacological characterization of the ch-5-HT1A receptor using binding and functional assays.

  17. Genome Sequence of Avian Escherichia coli Strain IHIT25637, an Extraintestinal Pathogenic E. coli Strain of ST131 Encoding Colistin Resistance Determinant MCR-1

    PubMed Central

    Göttig, Stephan; Bülte, Maria; Fiedler, Sophie; Tietgen, Manuela; Leidner, Ursula; Heydel, Carsten; Bauerfeind, Rolf; Semmler, Torsten

    2016-01-01

    Sequence type 131 (ST131) is one of the predominant Escherichia coli lineages among extraintestinal pathogenic E. coli (ExPEC) that causes a variety of diseases in humans and animals and frequently shows multidrug resistance. Here, we report the first genome sequence of an ST131-ExPEC strain from poultry carrying the plasmid-encoded colistin resistance gene mcr-1. PMID:27587807

  18. Biological components and bioelectronic interfaces of water splitting photoelectrodes for solar hydrogen production.

    PubMed

    Braun, Artur; Boudoire, Florent; Bora, Debajeet K; Faccio, Greta; Hu, Yelin; Kroll, Alexandra; Mun, Bongjin S; Wilson, Samuel T

    2015-03-09

    Artificial photosynthesis (AP) is inspired by photosynthesis in nature. In AP, solar hydrogen can be produced by water splitting in photoelectrochemical cells (PEC). The necessary photoelectrodes are inorganic semiconductors. Light-harvesting proteins and biocatalysts can be coupled with these photoelectrodes and thus form bioelectronic interfaces. We expand this concept toward PEC devices with vital bio-organic components and interfaces, and their integration into the built environment. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Fabrication Development for Nanowire GHz-Counting-Rate Single-Photon Detectors

    DTIC Science & Technology

    2005-06-01

    without PEC had a higher variation in linewidths: the largest variation between any two measurements was 15 nm. Fig. 2(d) shows a plot of the linewidth...portion of the meander pattern written with PEC showing uniform 90 nm wide lines with smooth line edges formed in HSQ. (d) Plot of measured widths at...Kelvin-resistor test structure used to evaluate superconductivity of nanowires. (c) Normalized resistance vs. temperature plots showing the

  20. Iodine-doped-poly(3,4-ethylenedioxythiophene)-modified Si nanowire 1D core-shell arrays as an efficient photocatalyst for solar hydrogen generation.

    PubMed

    Yang, Tian; Wang, Hui; Ou, Xue-Mei; Lee, Chun-Sing; Zhang, Xiao-Hong

    2012-12-04

    A new 1D core-shell strategy is demonstrated for a hydrogen-generation photo-electrochemical cell (PEC). This Si/iodine-doped poly(3,4-ethylenedioxythiophene) (PEDOT) 1D nanocable array shows an encouraging solar-to-chemical energy-conversion efficiency. Coating with iodine-doped PEDOT can effectively enhance the photocatalytic efficiency and stability of SiNW arrays. The PEC model proposed shows a potentially promising structure for H(2) production using solar energy.

  1. Antibiotic resistance and virulence genes of extraintestinal pathogenic Escherichia coli from tropical estuary, South India.

    PubMed

    Sukumaran, Divya; Mohamed Hatha, Abdulla A

    2015-05-18

    Escherichia coli strains can cause a variety of intestinal and extraintestinal diseases. Extraintestinal pathogenic E. coli (ExPEC) strains have the ability to cause severe extraintestinal infections. Multidrug resistance among ExPEC could complicate human infections. Escherichia coli strains were isolated during the period of January 2010 to December 2012 from five different stations set at Cochin estuary. Susceptibility testing was determined by the disk-diffusion method using nine different antimicrobial agents. A total of 155 strains of Escherichia coli were screened for the presence of virulence factor genes including papAH, papC, sfa/focDE, iutA,and kpsMT II associated with ExPEC. Among the 155 E. coli isolates, 26 (16.77%), carried two or more virulence genes typical of ExPEC. Furthermore, 19.23% of the ExPEC isolates with multidrug resistance were identified to belong to phylogenetic groups B2 and D. Statistically significant association of iutA gene in ExPEC was found with papC (p < 0.001) and kpsMT II (p < 0.001) genes. ExPEC isolates were mainly resistant to ampicillin (23.07%), tetracycline (19.23%), co-trimoxazole (15.38%), and cefotaxime (15.38%). The adhesion genes papAH and sfa/focDE were positively associated with resistance to gentamicin, chloramphenicol, and cefotaxime (p < 0.05). Co-occurrence of virulence factor genes with antibiotic resistance among ExPEC poses considerable threat to those who use this aquatic system for a living and for recreation.

  2. Pectin and high-amylose maize starch increase caecal hydrogen production and relieve hepatic ischaemia-reperfusion injury in rats.

    PubMed

    Nishimura, Naomichi; Tanabe, Hiroki; Sasaki, Yumi; Makita, Yui; Ohata, Misako; Yokoyama, Saori; Asano, Mami; Yamamoto, Tatsuro; Kiriyama, Shuhachi

    2012-02-01

    We investigated whether the feeding of high H2-generating dietary fibre and resistant starch (RS) could suppress hepatic ischaemia-reperfusion (IR) injury, which results from oxidative stress, in rats fed a pectin (Pec) or high-amylose maize starch (HAS) diet. Male Sprague-Dawley rats were fed a control (C) diet, with or without Pec (0-5 % Pec) or HAS (0-30 % HAS) supplementation for 7 d. Portal H2 concentration showed a significant dose-dependent increase with the amount of Pec or HAS supplementation. Plasma alanine and aspartate aminotransferase activities remarkably increased in the C rats (5 % cellulose) due to IR treatment, while it decreased significantly or showed tendencies to decrease in 5 % Pec and 20 % HAS diet-fed rats. The hepatic oxidised glutathione (GSSG):total glutathione ratio increased significantly in IR rats maintained on the C diet compared with sham-operated rats. On the other hand, reduced glutathione (GSH):total glutathione and GSH:GSSG ratios decreased significantly. The GSSG:total glutathione ratio that increased due to IR treatment decreased significantly on HAS and Pec intake, while GSH:total glutathione and GSH:GSSG ratios increased significantly. Hepatic sinusoids of IR rats fed the C diet were occluded, but those of IR rats fed the Pec diet were similar to those in the sham-operated rats. In conclusion, we found that Pec or HAS, which enhance H2 generation in the large intestine, alleviated hepatic IR injury. The present study demonstrates another physiological significance of dietary fibre and RS.

  3. Sources, distribution and export coefficient of phosphorus in lowland polders of Lake Taihu Basin, China.

    PubMed

    Huang, Jiacong; Gao, Junfeng; Jiang, Yong; Yin, Hongbin; Amiri, Bahman Jabbarian

    2017-09-21

    Identifying phosphorus (P) sources, distribution and export from lowland polders is important for P pollution management, however, is challenging due to the high complexity of hydrological and P transport processes in lowland areas. In this study, the spatial pattern and temporal dynamics of P export coefficient (PEC) from all the 2539 polders in Lake Taihu Basin, China were estimated using a coupled P model for describing P dynamics in a polder system. The estimated amount of P export from polders in Lake Taihu Basin during 2013 was 1916.2 t/yr, with a spatially-averaged PEC of 1.8 kg/ha/yr. PEC had peak values (more than 4.0 kg/ha/yr) in the polders near/within the large cities, and was high during the rice-cropping season. Sensitivity analysis based on the coupled P model revealed that the sensitive factors controlling the PEC varied spatially and changed through time. Precipitation and air temperature were the most sensitive factors controlling PEC. Culvert controlling and fertilization were sensitive factors controlling PEC during some periods. This study demonstrated an estimation of PEC from 2539 polders in Lake Taihu Basin, and an identification of sensitive environmental factors affecting PEC. The investigation of polder P export in a watershed scale is helpful for water managers to learn the distribution of P sources, to identify key P sources, and thus to achieve best management practice in controlling P export from lowland areas. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Quantum-size-controlled photoelectrochemical etching of semiconductor nanostructures

    DOEpatents

    Fischer, Arthur J.; Tsao, Jeffrey Y.; Wierer, Jr., Jonathan J.; Xiao, Xiaoyin; Wang, George T.

    2016-03-01

    Quantum-size-controlled photoelectrochemical (QSC-PEC) etching provides a new route to the precision fabrication of epitaxial semiconductor nanostructures in the sub-10-nm size regime. For example, quantum dots (QDs) can be QSC-PEC-etched from epitaxial InGaN thin films using narrowband laser photoexcitation, and the QD sizes (and hence bandgaps and photoluminescence wavelengths) are determined by the photoexcitation wavelength.

  5. Variational principles for the static electric and magnetic polarizabilities of anisotropic media with perfect electric conductor inclusions

    NASA Astrophysics Data System (ADS)

    Sjöberg, Daniel

    2009-08-01

    We present four variational principles for the electric and magnetic polarizabilities for a structure consisting of anisotropic media with perfect electric conductor (PEC) inclusions. From these principles, we derive monotonicity results and upper and lower bounds on the electric and magnetic polarizabilities. When computing the polarizabilities numerically, the bounds can be used as error bounds. The variational principles demonstrate important differences between electrostatics and magnetostatics when PEC bodies are present.

  6. Human and avian extraintestinal pathogenic Escherichia coli: infections, zoonotic risks, and antibiotic resistance trends.

    PubMed

    Mellata, Melha

    2013-11-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) constitutes ongoing health concerns for women, newborns, elderly, and immunocompromised individuals due to increased numbers of urinary tract infections (UTIs), newborn meningitis, abdominal sepsis, and septicemia. E. coli remains the leading cause of UTIs, with recent investigations reporting the emergence of E. coli as the predominant cause of nosocomial and neonatal sepsis infections. This shift from the traditional Gram-positive bacterial causes of nosocomial and neonatal sepsis infections could be attributed to the use of intrapartum chemoprophylaxis against Gram-positive bacteria and the appearance of antibiotic (ATB) resistance in E. coli. While ExPEC strains cause significant healthcare concerns, these bacteria also infect chickens and cause the poultry industry economic losses due to costs of containment, mortality, and disposal of carcasses. To circumvent ExPEC-related costs, ATBs are commonly used in the poultry industry to prevent/treat microbial infections and promote growth and performance. In an unfortunate linkage, chicken products are suspected to be a source of foodborne ExPEC infections and ATB resistance in humans. Therefore, the emergence of multidrug resistance (MDR) (resistance to three or more classes of antimicrobial agents) among avian E. coli has created major economic and health concerns, affecting both human healthcare and poultry industries. Increased numbers of immunocompromised individuals, including the elderly, coupled with MDR among ExPEC strains, will continue to challenge the treatment of ExPEC infections and likely lead to increased treatment costs. With ongoing complications due to emerging ATB resistance, novel treatment strategies are necessary to control ExPEC infections. Recognizing and treating the zoonotic risk posed by ExPEC would greatly enhance food safety and positively impact human health.

  7. Natural occurring 2-(2-phenylethyl) chromones, structure elucidation and biological activities.

    PubMed

    Ibrahim, Sabrin R M; Mohamed, Gamal A

    2015-01-01

    2-(2-Phenylethyl) chromone (PEC), an uncommon class of chromones, possesses a phenylethyl substituent at the C2 position. They have been isolated from a few plant species. They have promising biological activities such as neuro-protective, cytotoxic, acetylcholinesterase inhibitory, antibacterial and anti-inflammatory. This review focuses on the naturally occurring PEC derivatives, their sources, physical and spectral data, as well as biological activities.

  8. Human and Avian Extraintestinal Pathogenic Escherichia coli: Infections, Zoonotic Risks, and Antibiotic Resistance Trends

    PubMed Central

    2013-01-01

    Abstract Extraintestinal pathogenic Escherichia coli (ExPEC) constitutes ongoing health concerns for women, newborns, elderly, and immunocompromised individuals due to increased numbers of urinary tract infections (UTIs), newborn meningitis, abdominal sepsis, and septicemia. E. coli remains the leading cause of UTIs, with recent investigations reporting the emergence of E. coli as the predominant cause of nosocomial and neonatal sepsis infections. This shift from the traditional Gram-positive bacterial causes of nosocomial and neonatal sepsis infections could be attributed to the use of intrapartum chemoprophylaxis against Gram-positive bacteria and the appearance of antibiotic (ATB) resistance in E. coli. While ExPEC strains cause significant healthcare concerns, these bacteria also infect chickens and cause the poultry industry economic losses due to costs of containment, mortality, and disposal of carcasses. To circumvent ExPEC-related costs, ATBs are commonly used in the poultry industry to prevent/treat microbial infections and promote growth and performance. In an unfortunate linkage, chicken products are suspected to be a source of foodborne ExPEC infections and ATB resistance in humans. Therefore, the emergence of multidrug resistance (MDR) (resistance to three or more classes of antimicrobial agents) among avian E. coli has created major economic and health concerns, affecting both human healthcare and poultry industries. Increased numbers of immunocompromised individuals, including the elderly, coupled with MDR among ExPEC strains, will continue to challenge the treatment of ExPEC infections and likely lead to increased treatment costs. With ongoing complications due to emerging ATB resistance, novel treatment strategies are necessary to control ExPEC infections. Recognizing and treating the zoonotic risk posed by ExPEC would greatly enhance food safety and positively impact human health. PMID:23962019

  9. Enhanced Photoelectrocatalytic Decomplexation of Cu-EDTA and Cu Recovery by Persulfate Activated by UV and Cathodic Reduction.

    PubMed

    Zeng, Huabin; Liu, Shanshan; Chai, Buyu; Cao, Di; Wang, Yan; Zhao, Xu

    2016-06-21

    In order to enhance Cu-EDTA decomplexation and copper cathodic recovery via the photoelectrocatalytic (PEC) process, S2O8(2-) was introduced into the PEC system with a TiO2/Ti photoanode. At a current density of 0.2 mA/cm(2) and initial solution pH of 3.0, the decomplexation ratio of Cu complexes was increased from 47.5% in the PEC process to 98.4% with 5 mM S2O8(2-) addition into the PEC process (PEC/S2O8(2-)). Correspondently, recovery percentage of Cu was increased to 98.3% from 47.4% within 60 min. It was observed that nearly no copper recovery occurred within the initial reaction period of 10 min. Combined with the analysis of ESR and electrochemical LSV curves, it was concluded that activation of S2O8(2-) into SO4(·-) radicals by cathodic reduction occurred, which was prior to the reduction of liberated Cu(2+) ions. UV irradiation of S2O8(2-) also led to the production of SO4(·-). The generated SO4(·-) radicals enhanced the oxidation of Cu-EDTA. After the consumption of S2O8(2-), the Cu recovery via cathodic reduction proceeded quickly. Acidification induced by the transformation of SO4(·-) to OH· favored the copper cathodic recovery. The combined PEC/S2O8(2-) process was also efficient for the TOC removal from a real electroplating wastewater with the Cu recovery efficiency higher than 80%.

  10. Photoelectrochemical etching of InxGa1-xN

    NASA Astrophysics Data System (ADS)

    Hwang, J. M.; Hsieh, J. T.; Ko, C. Y.; Hwang, H. L.; Hung, W. H.

    2000-06-01

    Photoelectrochemical (PEC) etching of InxGa1-xN in the KOH solution under illumination of a Hg-arc lamp is studied. An indium oxide surface layer is formed during PEC etching, which slows down the etching rate. The PEC etch rate of InxGa1-xN is determined by dissolution of indium oxides into the solution. Increase of the solution temperature results in an increase of solubility of indium oxides and thus enhances the PEC etch rate. It is found that stirring the solution can accelerate indium oxides to dissolve into the solution and increase the etch rate. The thick indium oxide layer on the PEC-etched InxGa1-xN surface can be effectively removed by the treatment of using a hot 6N HCl solution. A post-treatment by using a 3.2 M KOH solution can provide a smooth sidewall on the PEC-etched surface for the potential application to laser cavity.

  11. Photoelectrochemical solar water splitting using electrospun TiO2 nanofibers

    NASA Astrophysics Data System (ADS)

    Mali, Mukund G.; An, Seongpil; Liou, Minho; Al-Deyab, Salem S.; Yoon, Sam S.

    2015-02-01

    TiO2 nano-fibrous films of thicknesses ranging from 0.17 to 3.24 μm were prepared on an indium-doped tin oxide substrate using an electrospinning technique for which the spinning time was varied from 5 to 60 min. The structural and morphological aspects were studied by means of XRD, Raman, and SEM analyses. The photoelectrochemical (PEC) properties of the films were tested by performing current-potential measurements. The optimal PEC performance was explored by varying the experimental conditions, specifically, the spinning time (5-60 min) and the annealing temperature (300, 500, and 700 °C). A comparison of the PEC performance of all the NF film thicknesses (0.17, 0.31, 1.53, 2.16, 4.67, and 7.53 μm) revealed that a thickness of 4.67 μm, that is, a film formed by electrospinning over a duration of 45 min, exhibited the optimum level of PEC performance. This film generated a photocurrent of around 150 μA/cm2, which was larger than the PEC values produced by the other films. The PEC performance of the 7.53-μm TiO2 NF film (produced by coating for 60 min) was found to be inferior to that of all the other thicknesses.

  12. Dual ionic interaction system based on polyelectrolyte complex and ionic, injectable, and thermosensitive hydrogel for sustained release of human growth hormone.

    PubMed

    Park, Mi-Ran; Seo, Bo-Bae; Song, Soo-Chang

    2013-01-01

    A dual ionic interaction system composed of a positively charged polyelectrolyte complex (PEC) containing human growth hormone (hGH) and anionic thermosensitive hydrogel has been suggested for sustained delivery of bioactive hGH. The PEC was prepared by ionic interaction between negatively charged hGH and positively charged protamine sulfate (PS) to suppress diffusion of hGH. Moreover, we loaded the positively charged PEC into an anionic, injectable, and thermosensitive poly(organophosphazene) hydrogel to enhance sustained release of hGH by dual ionic interactions. PS formed a spherical complex with hGH, and their ionic interaction grew stronger with increasing amounts of PS. From a weight ratio of 0.5, the PS/hGH complex had a size and zeta-potential that were constantly maintained around 500 nm and +8 mV, respectively, in 0.9% NaCl. The PEC-loaded hydrogels suppressed the initial burst release of hGH and extended the release period in vitro and in vivo. In a pharmacokinetic study in rats, the PEC-loaded anionic hydrogel extended half-life 13-fold with similar area under the curve (AUC) compared to hGH solution. Furthermore, single injection of PEC-loaded anionic hydrogel showed a more increased growth rate than daily injection of hGH solution for 7 days in hypophysectomized rats, demonstrating its potential as an injectable, sustained delivery system that can release bioactive hGH.

  13. In-situ generated H₂O₂ induced efficient visible light photo-electrochemical catalytic oxidation of PCP-Na with TiO₂.

    PubMed

    Liu, Wei; Liu, Huichao; Ai, Zhihui

    2015-05-15

    In this study, we developed a novel photo-electrochemical catalytic oxidation wastewater treatment system by interacting the cathodic in-situ generated H₂O₂ with TiO₂ suspension to form interfacial ≡ Ti(IV)OOH species, which endowed the PEC system with superior efficiency for degrading sodium pentachlorophenate (PCP-Na) under visible light irradiation at neutral pH. The apparent PCP-Na degradation rate constant of the PEC system was more than 10 times that of the electrochemical oxidation counterpart. In the PEC system, the interfacial ≡ Ti(IV)OOH species injected electrons to the conduction band of TiO₂ to initiate the activation of O₂ and the in-situ generated H₂O₂ adsorbed on the surface of TiO₂, lead to producing reactive oxygen species of superoxide anions and hydroxyl radicals, which were responsible for the dechlorination and mineralization of PCP-Na during the PEC process, respectively. The dosage of TiO₂ catalyst and the current intensity applied on PCP-Na degradation were optimized. This study develops a high efficient PEC oxidation system for wastewater treatment and provides new insight into the role of cathodic in-situ generated H₂O₂ on PEC oxidation of PCP-Na with TiO₂ under visible light irradiation. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Label-free photoelectrochemical immunoassay for CEA detection based on CdS sensitized WO3@BiOI heterostructure nanocomposite.

    PubMed

    Han, Qingzhi; Wang, Rongyu; Xing, Bin; Zhang, Tong; Khan, Malik Saddam; Wu, Dan; Wei, Qin

    2018-01-15

    In this work, a label-free photoelectrochemical (PEC) immunosensor for the detection of carcino embryonic antigen (CEA) was developed based on CdS nanowires (NWs) sensitized WO3@BiOI heterostructure. The construction procedure of ITO/WO3@BiOI@CdS electrode was done by dipping the WO3@BiOI modified indium-tin oxide (ITO) electrode interchangeably into [Cd(NH3)4](2+) and S(2-) solution for several times. Then the ITO/WO3@BiOI@CdS electrode was used as a matrix for the subsequent immobilization of CEA antibody (Ab). The obtained label-free PEC immunosensor showed an excellent PEC performance toward CEA detection. Under optimal conditions, the PEC immunosensor have a sensitive response to CEA in a liner range of 0.01ng/mL to 50ng/mL with a detection limit of 3.2pg/mL. The proposed PEC immunosensor exhibited good stability, high sensitivity as well as reproducibility and storage stability. Moreover, the obtained PEC immunosensor also showed a satisfied result in human serum sample analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Reduced graphene oxide modified highly ordered TiO2 nanotube arrays photoelectrode with enhanced photoelectrocatalytic performance under visible-light irradiation.

    PubMed

    Zhai, Chunyang; Zhu, Mingshan; Lu, Yongtao; Ren, Fangfang; Wang, Caiqin; Du, Yukou; Yang, Ping

    2014-07-28

    In this paper, reduced graphene oxide modified highly ordered TiO2 nanotube arrays (RGO-TNTs) have been fabricated and used for photoelectrocatalytic (PEC) degradation of organic pollutants under visible light irradiation. Firstly, the RGO-TNT electrode was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman, FT-IR, X-ray photoelectron spectroscopy (XPS) and UV-vis diffuse reflectance spectroscopy. The responsive photocurrent and electrochemical impedance spectroscopy (EIS) results indicated that our present RGO-TNTs displayed superior photoresponsive and electron transfer performances compared with bare TNTs. Moreover, by comparison with bare TNT electrode, the RGO-TNT arrays showed stable and evidently improved PEC activity for degradation of methyl orange (MO) under visible light illumination. This might be attributed to the introduction of RGO, which extended the absorption edge and promoted electron-hole separation in the PEC process. Furthermore, owing to the synergetic effect of photocatalysis and electrocatalysis in the PEC process, the efficiency of PEC process (3.0 × 10(-3) min(-1)) is ca. 7.9 and 2.5 times faster than that of the electrochemical process (3.8 × 10(-4) min(-1)) and photocatalytic process (1.2 × 10(-3) min(-1)), respectively. Our investigation likely provides new opportunities for developing stable and efficient one-dimensional graphene modified TNT-based catalysts for PEC degradation of organic pollutants under visible light illumination.

  16. Highly Versatile Polyelectrolyte Complexes for Improving the Enzyme Replacement Therapy of Lysosomal Storage Disorders.

    PubMed

    Giannotti, Marina I; Abasolo, Ibane; Oliva, Mireia; Andrade, Fernanda; García-Aranda, Natalia; Melgarejo, Marta; Pulido, Daniel; Corchero, José L; Fernández, Yolanda; Villaverde, Antonio; Royo, Miriam; García-Parajo, María F; Sanz, Fausto; Schwartz, Simó

    2016-10-05

    Lysosomal storage disorders are currently treated by enzyme replacement therapy (ERT) through the direct administration of the unprotected recombinant protein to the patients. Herein we present an ionically cross-linked polyelectrolyte complex (PEC) composed of trimethyl chitosan (TMC) and α-galactosidase A (GLA), the defective enzyme in Fabry disease, with the capability of directly targeting endothelial cells by incorporating peptide ligands containing the RGD sequence. We assessed the physicochemical properties, cytotoxicity, and hemocompatibility of RGD-targeted and untargeted PECs, the uptake by endothelial cells and the intracellular activity of PECs in cell culture models of Fabry disease. Moreover, we also explored the effect of different freeze-drying procedures in the overall activity of the PECs. Our results indicate that the use of integrin-binding RGD moiety within the PEC increases their uptake and the efficacy of the GLA enzyme, while the freeze-drying allows the activity of the therapeutic protein to remain intact. Overall, these results highlight the potential of TMC-based PECs as a highly versatile and feasible drug delivery system for improving the ERT of lysosomal storage disorders.

  17. Microscopic endometrial perivascular epithelioid cell nodules: a case report with the earliest presentation of a uterine perivascular epithelioid cell tumor.

    PubMed

    Fang, Chia-Lang; Lin, Yun-Ho; Chen, Wei-Yu

    2012-09-03

    Perivascular epithelioid cell (PEC) tumors (PEComas) are a family of related mesenchymal tumors composed of PECs which co-express melanocytic and smooth muscle markers. Although their distinctive histologic, immunohistochemical, ultrastructural, and genetic features have been clearly demonstrated, their histogenesis and normal counterpart remain largely unknown. Precursor lesions of PEComas have rarely been reported. We herein describe a tuberous sclerosis patient with microscopic PEC nodules in the endometrium of adenomyosis, pelvic endometriosis, an ovarian endometriotic cyst, and the endometrium of the uterine cavity. The nodules showed a mixture of spindle-shaped and epithelioid cells concentrically arranged around small arteries. The cells exhibited uniform nuclei, light eosinophilic cytoplasm, and immunoreactivity with HMB-45 and CD10. Some nodules revealed continuity with a PEComa in the myometrium. These findings support microscopic endometrial PEC nodules possibly being precursor lesions of uterine PEComas. The wide distribution of the nodules in the pelvis may be related to the multicentricity of PEComas in tuberous sclerosis patients. Owing to the immunoreactivity with CD10, microscopic endometrial PEC nodules may be misinterpreted as endothelial stromal cells unless melanocytic markers are stained. To the best of our knowledge, this is a case with the earliest manifestation of PEC lesions occurring in the endometrium. Virtual slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/9658280017862643.

  18. Engineering MoSx/Ti/InP Hybrid Photocathode for Improved Solar Hydrogen Production

    PubMed Central

    Li, Qiang; Zheng, Maojun; Zhong, Miao; Ma, Liguo; Wang, Faze; Ma, Li; Shen, Wenzhong

    2016-01-01

    Due to its direct band gap of ~1.35 eV, appropriate energy band-edge positions, and low surface-recombination velocity, p-type InP has attracted considerable attention as a promising photocathode material for solar hydrogen generation. However, challenges remain with p-type InP for achieving high and stable photoelectrochemical (PEC) performances. Here, we demonstrate that surface modifications of InP photocathodes with Ti thin layers and amorphous MoSx nanoparticles can remarkably improve their PEC performances. A high photocurrent density with an improved PEC onset potential is obtained. Electrochemical impedance analyses reveal that the largely improved PEC performance of MoSx/Ti/InP is attributed to the reduced charge-transfer resistance and the increased band bending at the MoSx/Ti/InP/electrolyte interface. In addition, the MoSx/Ti/InP photocathodes function stably for PEC water reduction under continuous light illumination over 2 h. Our study demonstrates an effective approach to develop high-PEC-performance InP photocathodes towards stable solar hydrogen production. PMID:27431993

  19. Confined Flocculation of Ionic Pollutants by Poly(L-dopa)-Based Polyelectrolyte Complexes in Hydrogel Beads for Three-Dimensional, Quantitative, Efficient Water Decontamination.

    PubMed

    Yu, Li; Liu, Xiaokong; Yuan, Weichang; Brown, Lauren Joan; Wang, Dayang

    2015-06-16

    The development of simple and recyclable adsorbents with high adsorption capacity is a technical imperative for water treatment. In this work, we have successfully developed new adsorbents for the removal of ionic pollutants from water via encapsulation of polyelectrolyte complexes (PECs) made from positively charged poly(allylamine hydrochloride) (PAH) and negatively charged poly(l-3,4-dihydroxyphenylalanine) (PDopa), obtained via the self-polymerization of l-3,4-dihydroxyphenylalanine (l-Dopa). Given the outstanding mass transport through the hydrogel host matrixes, the PDopa-PAH PEC guests loaded inside can effectively and efficiently remove various ionic pollutants, including heavy metal ions and ionic organic dyes, from water. The adsorption efficiency of the PDopa-PAH PECs can be quantitatively correlated to and tailored by the PDopa-to-PAH molar ratio. Because PDopa embodies one catechol group, one carboxyl group, and one amino group in each repeating unit, the resulting PDopa-PAH PECs exhibit the largest capacity of adsorption of heavy metal ions compared to available adsorbents. Because both PDopa and PAH are pH-sensitive, the PDopa-PAH PEC-loaded agarose hydrogel beads can be easily and completely recovered after the adsorption of ionic pollutants by adjusting the pH of the surrounding media. The present strategy is similar to the conventional process of using PECs to flocculate ionic pollutants from water, while in our system flocculation is confined to the agarose hydrogel beads, thus allowing easy separation of the resulting adsorbents from water.

  20. Patterned Microstructure Fabrication: Polyelectrolyte Complexes vs Polyelectrolyte Multilayers

    PubMed Central

    Gai, Meiyu; Frueh, Johannes; Kudryavtseva, Valeriya L.; Mao, Rui; Kiryukhin, Maxim V.; Sukhorukov, Gleb B.

    2016-01-01

    Polyelectrolyte complexes (PEC) are formed by mixing the solutions of oppositely charged polyelectrolytes, which were hitherto deemed “impossible” to process, since they are infusible and brittle when dry. Here, we describe the process of fabricating free-standing micro-patterned PEC films containing array of hollow or filled microchambers by one-step casting with small applied pressure and a PDMS mould. These structures are compared with polyelectrolyte multilayers (PEM) thin films having array of hollow microchambers produced from a layer-by-layer self-assembly of the same polyelectrolytes on the same PDMS moulds. PEM microchambers “cap” and “wall” thickness depend on the number of PEM bilayers, while the “cap” and “wall” of the PEC microchambers can be tuned by varying the applied pressure and the type of patterned mould. The proposed PEC production process omits layering approaches currently employed for PEMs, reducing the production time from ~2 days down to 2 hours. The error-free structured PEC area was found to be significantly larger compared to the currently-employed microcontact printing for PEMs. The sensitivity of PEC chambers towards aqueous environments was found to be higher compared to those composed of PEM. PMID:27830831

  1. Structure and flow properties of block copolyelectrolyte hydrogels

    NASA Astrophysics Data System (ADS)

    Srivastava, Samanvaya; Tirrell, Matthew

    2015-03-01

    Polyelectrolyte complexes (PEC) are dense, polymer-rich phases that form when oppositely charged polyelectrolyte chains spontaneously associate and phase separate in aqueous mediums. Bulk phase separation of the PECs can be evaded by combining one or both of the polyelectrolytes with a neutral polymer, thus engineering pathways for self-assembly of PEC based micelles and hydrogels with large-scale ordering of the nanoscale PEC domains. The PEC domains in these assemblies can encapsulate both hydrophobic and hydrophilic therapeutics and thus have tremendous potential in drug delivery, diagnostic and tissue engineering applications. This study will present insights on the equilibrium structure and self-assembly kinetics of PEC hybrid hydrogels through detailed rheology studies of self-assembled materials comprising of functionalized polyallyl glycidyl ethers (PAGE) connected to either single poly(ethylene glycol) (PEG) chain to form diblock copolymers or as functionalized end-groups on a triblock copolymer with a PEG midblock. The effect of key parameters such as polymer concentration, polymer block lengths, salt, ionic strength, and degree of charge mismatch on the equilibrium materials properties will be discussed, with a special emphasis on the temporal evolution of flow properties, and will lead to comparisons with the rheology models for associating polymers. Complementary studies with extensive static and dynamic light, X-ray and neutron scattering investigations will also be presented, thus providing a comprehensive structural description of these materials.

  2. Design of a Dual Channel Self-Reference Photoelectrochemical Biosensor.

    PubMed

    Hao, Nan; Zhang, Ying; Zhong, Hui; Zhou, Zhou; Hua, Rong; Qian, Jing; Liu, Qian; Li, Henan; Wang, Kun

    2017-10-03

    Photoelectrochemical (PEC) biosensors are usually based on the single photocurrent change caused by biorecognition events between analytes and probes. However, the photocurrent may be influenced by other factors besides target analytes and bring a false result. To improve the accuracy and reliability of PEC detection, here we proposed the design of a dual channel self-reference PEC biosensors. CdTe and CdTe-graphene oxide (GO) were chosen as the two PEC active material and modified onto two adjacent areas on the ITO electrode. Then they were functionalized with Aflatoxin B1 (AFB1) aptamer through covalent binding or physical adsorption, respectively. The cathodic current from CdTe-GO and anodic current from CdTe can be well distinguished by adjusting the bias voltage. With the simultaneous application of "signal on" and "signal off" model, dual concentration information may be obtained in one detection and serve as a reference for each other. By comparing these two results, this sensor can clearly distinguish whether the signal change was caused by AFB1 or other interference factors. Compared to traditional PEC biosensors, this design can provide a better accuracy and reliability, which is promising in the future development of PEC detection.

  3. Engineering MoSx/Ti/InP Hybrid Photocathode for Improved Solar Hydrogen Production.

    PubMed

    Li, Qiang; Zheng, Maojun; Zhong, Miao; Ma, Liguo; Wang, Faze; Ma, Li; Shen, Wenzhong

    2016-07-19

    Due to its direct band gap of ~1.35 eV, appropriate energy band-edge positions, and low surface-recombination velocity, p-type InP has attracted considerable attention as a promising photocathode material for solar hydrogen generation. However, challenges remain with p-type InP for achieving high and stable photoelectrochemical (PEC) performances. Here, we demonstrate that surface modifications of InP photocathodes with Ti thin layers and amorphous MoSx nanoparticles can remarkably improve their PEC performances. A high photocurrent density with an improved PEC onset potential is obtained. Electrochemical impedance analyses reveal that the largely improved PEC performance of MoSx/Ti/InP is attributed to the reduced charge-transfer resistance and the increased band bending at the MoSx/Ti/InP/electrolyte interface. In addition, the MoSx/Ti/InP photocathodes function stably for PEC water reduction under continuous light illumination over 2 h. Our study demonstrates an effective approach to develop high-PEC-performance InP photocathodes towards stable solar hydrogen production.

  4. Engineering MoSx/Ti/InP Hybrid Photocathode for Improved Solar Hydrogen Production

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Zheng, Maojun; Zhong, Miao; Ma, Liguo; Wang, Faze; Ma, Li; Shen, Wenzhong

    2016-07-01

    Due to its direct band gap of ~1.35 eV, appropriate energy band-edge positions, and low surface-recombination velocity, p-type InP has attracted considerable attention as a promising photocathode material for solar hydrogen generation. However, challenges remain with p-type InP for achieving high and stable photoelectrochemical (PEC) performances. Here, we demonstrate that surface modifications of InP photocathodes with Ti thin layers and amorphous MoSx nanoparticles can remarkably improve their PEC performances. A high photocurrent density with an improved PEC onset potential is obtained. Electrochemical impedance analyses reveal that the largely improved PEC performance of MoSx/Ti/InP is attributed to the reduced charge-transfer resistance and the increased band bending at the MoSx/Ti/InP/electrolyte interface. In addition, the MoSx/Ti/InP photocathodes function stably for PEC water reduction under continuous light illumination over 2 h. Our study demonstrates an effective approach to develop high-PEC-performance InP photocathodes towards stable solar hydrogen production.

  5. Reverse Genetics System for Porcine Enteric Calicivirus, a Prototype Sapovirus in the Caliciviridae

    PubMed Central

    Chang, Kyeong-Ok; Sosnovtsev, Stanislav S.; Belliot, Gaël; Wang, Qiuhong; Saif, Linda J.; Green, Kim Y.

    2005-01-01

    A porcine enteric calicivirus (PEC), strain Cowden in the genus Sapovirus of the Caliciviridae family, can be propagated in a porcine kidney continuous cell line (LLC-PK) in the presence of bile acids in the cell culture medium. A full-length cDNA copy of the Cowden PEC genome was cloned into a plasmid vector directly downstream from the T7 RNA polymerase promoter, and capped RNA transcripts derived from this clone were infectious when transfected into LLC-PK cells. The recovery of PEC after transfection of RNA transcripts was dependent on the presence of bile acids, consistent with our recent identification of a bile acid-mediated signaling pathway required for PEC replication (Chang et al., Proc. Natl. Acad. Sci. USA 101:8733-8788, 2004). Recovery of virus was verified by detection of PEC antigen in transfected cells by immunofluorescence and enzyme-linked immunosorbent assays, direct observation of recovered viral particles by electron microscopy, and partial sequence analysis of their genomes (first 1,070 nucleotides) to differentiate them from tissue culture-adapted parental virus. The recovered virus retained its ability to infect piglets when administered by the oral route and showed an attenuated phenotype similar to that of the tissue culture-adapted parental virus. This reverse genetics system for PEC provides a new tool to study the molecular basis of replication and pathogenesis for caliciviruses associated with diarrheal disease. PMID:15650167

  6. Wavelength-resolved simultaneous photoelectrochemical bifunctional sensor on single interface: A newly in vitro approach for multiplexed DNA monitoring in cancer cells.

    PubMed

    Zheng, Yingning; Liang, Wenbin; Yuan, Yali; Xiong, Chengyi; Xie, Shunbi; Wang, Haijun; Chai, Yaqin; Yuan, Ruo

    2016-07-15

    Currently, the photoelectrochemical (PEC) strategies can just achieve single analyte detection on a single interface with limited detection efficiency. It is highly valuable but full of challenge to develop a PEC biosensor for multiple analytes evaluation on a single interface. For this point, the wavelength-selective photoactive materials, which could generate separated photocurrents under excitation lights with certain wavelengths, were mainly important to overcome this challenge. Herein, these wavelength-selective photoactive materials were successfully synthesized and served as signal indicators to construct a novel PEC biosensor for multiple analytes evaluation on a single interface for the first time. Moreover, an enzyme-assisted target recycling amplification strategy was introduced for ultrasensitive monitoring. As a result, the proposed PEC biosensor showed excellent analytical performance for both oral cancer (ORVOA 1) gene and p53 gene down to attomolar level. In addition, the fabricated PEC biosensor was employed to evaluate ORVOA 1 gene and p53 gene in Hela cells. This assay has laid the foundation for fabrication of simple, ultrasensitive and economical PEC diagnostic devices to detect multiple analytes in cells, which paved a new avenue for early diagnosis of cancer with higher efficiency and accuracy.

  7. Polyelectrolyte Complex Hydrogels: Self-assembly and the Influence of Charged and Neutral Blocks

    NASA Astrophysics Data System (ADS)

    Srivastava, Samanvaya; Goldfeld, David; Levi, Adam; Mao, Jun; Chen, Wei; Tirrell, Matthew

    Polyelectrolyte complexes (PEC) form when oppositely charged polyelectrolyte chains spontaneously associate and phase separate in aqueous mediums. Bulk phase separation of the PECs can be evaded by combining one or both of the polyelectrolytes with a neutral polymer, thus engineering pathways for self-assembled PEC micelles and hydrogels. The PEC domains in these assemblies can encapsulate therapeutics as well as genetic materials and thus have tremendous potential in drug delivery and tissue engineering applications. We will present insights on the equilibrium structure and self-assembly kinetics of PEC hydrogels with large-scale ordering of the nanoscale PEC domains through detailed structure characterization and rheology studies of self-assembled materials comprising of functionalized polyallyl glycidyl ethers (PAGE) connected to either single poly(ethylene glycol) (PEG) chain to form diblock copolymers or as functionalized end-groups on a triblock copolymer with a PEG midblock. The effect of key parameters such as polymer concentration, polymer block lengths, salt, ionic strength, and degree of charge mismatch on the equilibrium materials properties will be discussed, with a special emphasis on the structure-defining role of the charged blocks and the structure-directing role of neutral blocks. Additionally, interesting similarities, and differences between structures and dynamics of hydrogels comprising diblock and corresponding triblock polyelectrolytes, respectively, will be discussed.

  8. Photoelectrochemical enzymatic biosensors.

    PubMed

    Zhao, Wei-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

    2017-06-15

    Enzymatic biosensors have been valuable bioanalytical devices for analysis of diverse targets in disease diagnosis, biological and biomedical research, etc. Photoelectrochemical (PEC) bioanalysis is a recently emerged method that promptly becoming a subject of new research interests due to its attractive potential for future bioanalysis with high sensitivity and specificity. PEC enzymatic biosensors integrate the inherent sensitivities of PEC bioanalysis and the selectivity of enzymes and thus share their both advantages. Currently, PEC enzymatic biosensors have become a hot topic of significant research and the recent impetus has grown rapidly as demonstrated by increased research papers. Given the pace of advances in this area, this review will make a thorough discussion and survey on the fundamentals, sensing strategies, applications and the state of the art in PEC enzymatic biosensors, followed by future prospects based on our own opinions. We hope this work could provide an accessible introduction to PEC enzymatic biosensors for any scientist. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. A previously unrecognized role of C3a in proteinuric progressive nephropathy

    PubMed Central

    Morigi, Marina; Locatelli, Monica; Rota, Cinzia; Buelli, Simona; Corna, Daniela; Rizzo, Paola; Abbate, Mauro; Conti, Debora; Perico, Luca; Longaretti, Lorena; Benigni, Ariela; Zoja, Carlamaria; Remuzzi, Giuseppe

    2016-01-01

    Podocyte loss is the initial event in the development of glomerulosclerosis, the structural hallmark of progressive proteinuric nephropathies. Understanding mechanisms underlying glomerular injury is the key challenge for identifying novel therapeutic targets. In mice with protein-overload induced by bovine serum albumin (BSA), we evaluated whether the alternative pathway (AP) of complement mediated podocyte depletion and podocyte-dependent parietal epithelial cell (PEC) activation causing glomerulosclerosis. Factor H (Cfh−/−) or factor B-deficient mice were studied in comparison with wild-type (WT) littermates. WT+BSA mice showed podocyte depletion accompanied by glomerular complement C3 and C3a deposits, PEC migration to capillary tuft, proliferation, and glomerulosclerosis. These changes were more prominent in Cfh−/− +BSA mice. The pathogenic role of AP was documented by data that factor B deficiency preserved glomerular integrity. In protein-overload mice, PEC dysregulation was associated with upregulation of CXCR4 and GDNF/c-Ret axis. In vitro studies provided additional evidence of a direct action of C3a on proliferation and CXCR4-related migration of PECs. These effects were enhanced by podocyte-derived GDNF. In patients with proteinuric nephropathy, glomerular C3/C3a paralleled PEC activation, CXCR4 and GDNF upregulation. These results indicate that mechanistically uncontrolled AP complement activation is not dispensable for podocyte-dependent PEC activation resulting in glomerulosclerosis. PMID:27345360

  10. Bifunctional polydopamine thin film coated zinc oxide nanorods for label-free photoelectrochemical immunoassay.

    PubMed

    Yang, Yan; Hu, Weihua

    2017-05-01

    Photoelectrochemical (PEC) detection is a promising method for label-free immunoassay by reporting the specific biological recognition events with electrical signals. However, it is challenging to rationally incorporate immunosensing components with a photocurrent conversion interface, which generally necessitates multistep fabrication and careful tailoring of various components such as photoactive material and biological probe. For high detection reliability and reproducibility, it is highly desirable to rationally construct an efficient PEC interface with architecture as simple as possible. In this work, a novel yet simple PEC immunosensor based on bio-inspired polydopamine (PDA) thin film-coated zinc oxide (ZnO) nanorods was reported. In this PEC immunosensor, the PDA thin film serves simultaneously as a unique sensitizer for charge separation as well as a functional layer for probe antibody attachment. The photocurrent on this electrode under illumination decreases upon the immunoreaction on the surface, possibly due to the blocking effect of formed immunocomplexes on the access of reducing reagent to the photoelectrode, thus offering a simple and reliable platform for PEC label-free immunoassay. By using an antibody-antigen pair as a model, successful label-free immunoassay was achieved with a detection limit of 10pgmL(-1) and a dynamic range from 100pgmL(-1) to 500ngmL(-1). This work demonstrates intriguing electro-optical property and bioconjugation activity of PDA film and may pave the way toward advanced PEC immunoassays. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Poly(ethylene carbonate): a thermoelastic and biodegradable biomaterial for drug eluting stent coatings?

    PubMed

    Unger, F; Westedt, U; Hanefeld, P; Wombacher, R; Zimmermann, S; Greiner, A; Ausborn, M; Kissel, T

    2007-02-26

    A first feasibility study exploring the utility of poly(ethylene carbonate) (PEC) as coating material for drug eluting stents under in vitro conditions is reported. PEC (Mw 242 kDa, Mw/Mn=1.90) was found to be an amorphous polymer with thermoelastic properties. Tensile testing revealed a stress to strain failure of more than 600%. These properties are thought to be advantageous for expanding coated stents. In vitro cytotoxicity tests showed excellent cytocompatibility of PEC. Based on these findings, a new stenting concept was suggested, pre-coating a bare-metal stent with PPX-N as non-biodegradable basis and applying a secondary PEC coating using an airbrush method. After manual expansion, no delamination or destruction of the coating could be observed using scanning electron microscopy. The surface degradation-controlled release mechanism of PEC may provide the basis for "on demand" drug eluting stent coatings, releasing an incorporated drug predominantly at an inflamed implantation site upon direct contact with superoxide-releasing macrophages. As a release model, metal plates of a defined size and area were coated under the same conditions as the stents with PEC containing radiolabelled paclitaxel. An alkaline KO(2-) solution served as a superoxide source. Within 12 h, 100% of the incorporated paclitaxel was released, while only 20% of the drug was released in non-superoxide releasing control buffer within 3 weeks.

  12. Enhancement in hydrogen evolution using Au-TiO2 hollow spheres with microbial devices modified with conjugated oligoelectrolytes

    PubMed Central

    Ngaw, Chee Keong; Wang, Victor Bochuan; Liu, Zhengyi; Zhou, Yi; Kjelleberg, Staffan; Zhang, Qichun; Tan, Timothy Thatt Yang; Loo, Say Chye Joachim

    2015-01-01

    Objective: Although photoelectrochemical (PEC) water splitting heralds the emergence of the hydrogen economy, the need for external bias and low efficiency stymies the widespread application of this technology. By coupling water splitting (in a PEC cell) to a microbial fuel cell (MFC) using Escherichia coli as the biocatalyst, this work aims to successfully demonstrate a sustainable hybrid PEC–MFC platform functioning solely by biocatalysis and solar energy, at zero bias. Through further chemical modification of the photo-anode (in the PEC cell) and biofilm (in the MFC), the performance of the hybrid system is expected to improve in terms of the photocurrent generated and hydrogen evolved. Methods: The hybrid system constitutes the interconnected PEC cell with the MFC. Both PEC cell and MFC are typical two-chambered systems housing the anode and cathode. Au-TiO2 hollow spheres and conjugated oligoelectrolytes were synthesised chemically and introduced to the PEC cell and MFC, respectively. Hydrogen evolution measurements were performed in triplicates. Results: The hybrid PEC–MFC platform generated a photocurrent density of 0.35 mA/cm2 (~70× enhancement) as compared with the stand-alone P25 standard PEC cell (0.005 mA/cm2) under one-sun illumination (100 mW/cm2) at zero bias (0 V vs. Pt). This increase in photocurrent density was accompanied by continuous H2 production. No H2 was observed in the P25 standard PEC cell whereas H2 evolution rate was ~3.4 μmol/h in the hybrid system. The remarkable performance is attributed to the chemical modification of E. coli through the incorporation of novel conjugated oligoelectrolytes in the MFC as well as the lower recombination rate and higher photoabsorption capabilities in the Au-TiO2 hollow spheres electrode. Conclusions: The combined strategy of photo-anode modification in PEC cells and chemically modified MFCs shows great promise for future exploitation of such synergistic effects between MFCs and

  13. Occupational leg oedema is more reduced by antigraduated than by graduated stockings.

    PubMed

    Mosti, G; Partsch, H

    2013-05-01

    Elastic compression stockings exerting a progressive pressure, higher at the calf than at the ankle (progressive elastic compression stockings, PECS), have already proved to be more comfortable, easier to put on and more effective in improving venous pumping function compared to graduated compression elastic stockings (GECS). Nevertheless, PECS could have a negative effect on the prevention and treatment of oedema or even favour oedema formation. The aim of the present study was to investigate if, in normal volunteers, PECS are able to prevent leg swelling during their working shift. A total of 30 normal volunteers (14 males, 16 females aged 36.4 ± 6.6 years) staying standing or sitting during their shift were enrolled into the study. Their leg volume was measured at the beginning and at the end of their working shift on 2 consecutive days. On one day, the volunteers did not put on any stockings; on the other day, they wore GECS on one leg and PECS on the other. The difference between the leg volume measured at the end of the shift and the basal volume in the morning was called 'occupational oedema'. Interface pressure at points B1 and C was measured immediately after stockings' application and before removal. The volunteers were asked to report about difficulty of putting on the stockings and comfort during wearing time. The results were submitted to statistical analysis. The GECS and PECS groups had similar baseline leg volumes (3143 vs. 3154 ml) and occupational oedema (134 vs. 137.5 ml); after putting on the stockings, occupational oedema was reduced in both legs but the reduction was significantly greater with PECS (20 vs. 40 ml with GECS) (P < 0.05). Interface pressure at ankle level is higher with GECS both in supine and in standing position while at calf level it is higher with PECS both in supine and standing position. PECS are easier to put on and slightly more comfortable. PECS are easier to put on and more comfortable and produce a significantly higher

  14. Sediment contamination of residential streams in the metropolitan Kansas City area, USA: Part II. Whole-sediment toxicity to the amphipod Hyalella azteca.

    PubMed

    Tao, J; Ingersoll, C G; Kemble, N E; Dias, J R; Murowchick, J B; Welker, G; Huggins, D

    2010-10-01

    This is the second part of a study that evaluates the influence of nonpoint sources on the sediment quality of five adjacent streams within the metropolitan Kansas City area, central United States. Physical, chemical, and toxicity data (Hyalella azteca 28-day whole-sediment toxicity test) for 29 samples collected in 2003 were used for this evaluation, and the potential causes for the toxic effects were explored. The sediments exhibited a low to moderate toxicity, with five samples identified as toxic to H. azteca. Metals did not likely cause the toxicity based on low concentrations of metals in the pore water and elevated concentrations of acid volatile sulfide in the sediments. Although individual polycyclic aromatic hydrocarbons (PAHs) frequently exceeded effect-based sediment quality guidelines [probable effect concentrations (PECs)], only four of the samples had a PEC quotient (PEC-Q) for total PAHs over 1.0 and only one of these four samples was identified as toxic. For the mean PEC-Q for organochlorine compounds (chlordane, dieldrin, sum DDEs), 4 of the 12 samples with a mean PEC-Q above 1.0 were toxic and 4 of the 8 samples with a mean PEC-Q above 3.0 were toxic. Additionally, four of eight samples were toxic, with a mean PEC-Q above 1.0 based on metals, PAHs, polychlorinated biphenyls (PCBs), and organochlorine pesticides. The increase in the incidence of toxicity with the increase in the mean PEC-Q based on organochlorine pesticides or based on metals, PAHs, PCBs, and organochlorine pesticides suggests that organochlorine pesticides might have contributed to the observed toxicity and that the use of a mean PEC-Q, rather than PEC-Qs for individual compounds, might be more informative in predicting toxic effects. Our study shows that stream sediments subject to predominant nonpoint sources contamination can be toxic and that many factors, including analysis of a full suite of PAHs and pesticides of both past and present urban applications and the origins of

  15. Sediment contamination of residential streams in the metropolitan kansas city area, USA: Part II. whole-sediment toxicity to the amphipod hyalella azteca

    USGS Publications Warehouse

    Tao, J.; Ingersoll, C.G.; Kemble, N.E.; Dias, J.R.; Murowchick, J.B.; Welker, G.; Huggins, D.

    2010-01-01

    This is the second part of a study that evaluates the influence of nonpoint sources on the sediment quality of five adjacent streams within the metropolitan Kansas City area, central United States. Physical, chemical, and toxicity data (Hyalella azteca 28-day whole-sediment toxicity test) for 29 samples collected in 2003 were used for this evaluation, and the potential causes for the toxic effects were explored. The sediments exhibited a low to moderate toxicity, with five samples identified as toxic to H. azteca. Metals did not likely cause the toxicity based on low concentrations of metals in the pore water and elevated concentrations of acid volatile sulfide in the sediments. Although individual polycyclic aromatic hydrocarbons (PAHs) frequently exceeded effect-based sediment quality guidelines [probable effect concentrations (PECs)], only four of the samples had a PEC quotient (PEC-Q) for total PAHs over 1.0 and only one of these four samples was identified as toxic. For the mean PEC-Q for organochlorine compounds (chlordane, dieldrin, sum DDEs), 4 of the 12 samples with a mean PEC-Q above 1.0 were toxic and 4 of the 8 samples with a mean PEC-Q above 3.0 were toxic. Additionally, four of eight samples were toxic, with a mean PEC-Q above 1.0 based on metals, PAHs, polychlorinated biphenyls (PCBs), and organochlorine pesticides. The increase in the incidence of toxicity with the increase in the mean PEC-Q based on organochlorine pesticides or based on metals, PAHs, PCBs, and organochlorine pesticides suggests that organochlorine pesticides might have contributed to the observed toxicity and that the use of a mean PEC-Q, rather than PEC-Qs for individual compounds, might be more informative in predicting toxic effects. Our study shows that stream sediments subject to predominant nonpoint sources contamination can be toxic and that many factors, including analysis of a full suite of PAHs and pesticides of both past and present urban applications and the origins of

  16. Metagenomic analysis of sediments under seaports influence in the Equatorial Atlantic Ocean.

    PubMed

    Tavares, Tallita Cruz Lopes; Normando, Leonardo Ribeiro Oliveira; de Vasconcelos, Ana Tereza Ribeiro; Gerber, Alexandra Lehmkuhl; Agnez-Lima, Lucymara Fassarella; Melo, Vânia Maria Maciel

    2016-07-01

    Maritime ports are anthropogenic interventions capable of causing serious alterations in coastal ecosystems. In this study, we examined the benthic microbial diversity and community structure under the influence of two maritime ports, Mucuripe (MUC) and Pecém (PEC), at Equatorial Atlantic Ocean in Northeast Brazil. Those seaports differ in architecture, time of functioning, cargo handling and contamination. The microbiomes from MUC and PEC were also compared in silico to 11 other globally distributed marine microbiomes. The comparative analysis of operational taxonomic units (OTUs) retrieved by PCR-DGGE showed that MUC presents greater richness and β diversity of Bacteria and Archaea than PEC. In line with these results, metagenomic analysis showed that MUC and PEC benthic microbial communities share the main common bacterial phyla found in coastal environments, although can be distinguish by greater abundance of Cyanobacteria in MUC and Deltaproteobacteria in PEC. Both ports differed in Archaea composition, being PEC port sediments dominated by Thaumarchaeota. The microbiomes showed little divergence in their potential metabolic pathways, although shifts on the microbial taxonomic signatures involved in nitrogen and sulphur metabolic pathways were observed. The comparative analysis of different benthic marine metagenomes from Brazil, Australia and Mexico grouped them by the geographic location rather than by the type of ecosystem, although at phylum level seaport sediments share a core microbiome constituted by Proteobacteria, Cyanobacteria, Actinobacteria, Tenericuteres, Firmicutes, Bacteriodetes and Euryarchaeota. Our results suggest that multiple physical and chemical factors acting on sediments as a result of at least 60years of port operation play a role in shaping the benthic microbial communities at taxonomic level, but not at functional level.

  17. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol

    PubMed Central

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H.; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300–400 MPa), thymol concentration (100–200 ppm), and pressure-holding time (10–20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R2 = 0.94) and UPEC (R2 = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken. PMID:27379050

  18. Modeling the Inactivation of Intestinal Pathogenic Escherichia coli O157:H7 and Uropathogenic E. coli in Ground Chicken by High Pressure Processing and Thymol.

    PubMed

    Chien, Shih-Yung; Sheen, Shiowshuh; Sommers, Christopher H; Sheen, Lee-Yan

    2016-01-01

    Disease causing Escherichia coli commonly found in meat and poultry include intestinal pathogenic E. coli (iPEC) as well as extraintestinal types such as the Uropathogenic E. coli (UPEC). In this study we compared the resistance of iPEC (O157:H7) to UPEC in chicken meat using High Pressure Processing (HPP) in with (the hurdle concept) and without thymol essential oil as a sensitizer. UPEC was found slightly more resistant than E. coli O157:H7 (iPEC O157:H7) at 450 and 500 MPa. A central composite experimental design was used to evaluate the effect of pressure (300-400 MPa), thymol concentration (100-200 ppm), and pressure-holding time (10-20 min) on the inactivation of iPEC O157:H7 and UPEC in ground chicken. The hurdle approach reduced the high pressure levels and thymol doses imposed on the food matrices and potentially decreased food quality damaged after treatment. The quadratic equations were developed to predict the impact (lethality) on iPEC O157:H7 (R (2) = 0.94) and UPEC (R (2) = 0.98), as well as dimensionless non-linear models [Pr > F (<0.0001)]. Both linear and non-linear models were validated with data obtained from separated experiment points. All models may predict the inactivation/lethality within the same order of accuracy. However, the dimensionless non-linear models showed potential applications with parameters outside the central composite design ranges. The results provide useful information of both iPEC O157:H7 and UPEC in regard to how they may survive HPP in the presence or absence of thymol. The models may further assist regulatory agencies and food industry to assess the potential risk of iPEC O157:H7 and UPEC in ground chicken.

  19. Directing the phase behavior of polyelectrolyte complexes using chiral patterned peptides

    NASA Astrophysics Data System (ADS)

    Pacalin, Naomi M.; Leon, Lorraine; Tirrell, Matthew

    2016-10-01

    Polyelectrolyte complexes (PECs) have a broad range of promising applications as soft materials due to their self-assembly and diversity of structure and chemical composition. Peptide polymer PECs are highly biocompatible and biodegradable, making them particularly useful for encapsulation of food additives and flavors, micellar drug delivery, medical and underwater adhesives, fetal membrane patches, and scaffolds for cell growth in tissue engineering. While parameters affecting PEC formation and stability in regards to charge effects are well researched, little is known about the effects of van der Waals interactions, hydrogen bonding, and secondary structure in these materials. Peptide chirality provides a unique opportunity to manipulate PEC phase to modulate the amount of solid-like (precipitate) or liquid-like (coacervate) character by influencing hydrogen bonding interactions among peptide chains. In previous work, we showed that chiral peptides form solid complexes, while complexes with even one racemic peptide were fluid. This raised the interesting question of how long a homochiral sequence must be to result in solid phase formation. In this work, we designed chiral patterned peptides of polyglutamic acid and polylysine ranging from 50 to 90% L-chiral residues with increasing numbers of sequential L-chiral residues before a chirality change. These polymers were mixed together to form PECs. We observed that 8 or more sequential L-chiral residues are necessary to achieve both the appearance of a precipitate phase and sustained β-sheets in the complex, as determined by optical imaging and FTIR Spectroscopy. Less homochiral content results in formation of a coacervate phase. Thus, we show that chiral sequence can be used to control the phase transition of PECs. Understanding how to manipulate PEC phase using chiral sequence as presented here may enable tuning of the material properties to achieve the desired mechanical strength for coatings and polymer

  20. Molecular weight-dependent degradation and drug release of surface-eroding poly(ethylene carbonate).

    PubMed

    Bohr, Adam; Wang, Yingya; Harmankaya, Necati; Water, Jorrit J; Baldursdottír, Stefania; Almdal, Kristoffer; Beck-Broichsitter, Moritz

    2017-06-01

    Poly(ethylene carbonate) (PEC) is a unique biomaterial showing significant potential for controlled drug delivery applications. The current study investigated the impact of the molecular weight on the biological performance of drug-loaded PEC films. Following the preparation and thorough physicochemical characterization of diverse PEC (molecular weights: 85, 110, 133, 174 and 196kDa), the degradation and drug release behavior of rifampicin- and bovine serum albumin-loaded PEC films was investigated in vitro (in the presence and absence of cholesterol esterase), in cell culture (RAW264.7 macrophages) and in vivo (subcutaneous implantation in rats). All investigated samples degraded by means of surface erosion (mass loss, but constant molecular weight), which was accompanied by a predictable, erosion-controlled drug release pattern. Accordingly, the obtained in vitro degradation half-lives correlated well with the observed in vitro half-times of drug delivery (R(2)=0.96). Here, the PEC of the highest molecular weight resulted in the fastest degradation/drug release. When incubated with macrophages or implanted in animals, the degradation rate of PEC films superimposed the results of in vitro incubations with cholesterol esterase. Interestingly, SEM analysis indicated a distinct surface erosion process for enzyme-, macrophage- and in vivo-treated polymer films in a molecular weight-dependent manner. Overall, the molecular weight of surface-eroding PEC was identified as an essential parameter to control the spatial and temporal on-demand degradation and drug release from the employed delivery system. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Combined environmental risk assessment for 5-fluorouracil and capecitabine in Europe.

    PubMed

    Straub, Jürg Oliver

    2010-07-01

    An environmental risk assessment (ERA) was made for the old cytostatic active pharmaceutical ingredient 5-fluorouracil (5-FU) and for capecitabine (CAP), which is a prodrug of 5-FU. This ERA is based on published and company internal data as well as new test results for physicochemical, human metabolism, biodegradability, environmental partitioning and fate, and acute and chronic ecotoxicity properties of the active substance 5-FU as well as on use sales data for 5-FU and CAP in Europe. Predicted environmental concentrations (PECs) were extrapolated following the EMEA 2006 Guideline on ERA for human pharmaceuticals and the European Union 2003 Technical Guidance Document (TGD) for risk assessment as well as the TGD-based application EUSES v2.0. Actual amounts sold were taken from IMS Health Databases, in order to refine the default use and EMEA penetration factor as well as the PECs. Moreover, available measured environmental concentrations (MECs) were used to supplement PECs. A predicted no-effect concentration (PNEC) for 5-FU was derived from chronic ecotoxicity data. Except for the simplistic EMEA Phase I default PEC, the risk characterization by PEC:PNEC and MEC:PNEC ratios for various environmental compartments resulted in no significant risk. As the EMEA Phase I PEC does not integrate documented human metabolism and environmental degradation, in contrast to refined PEC derivations, it is inferred that the current use of CAP and 5-FU does not present any evident risk to the environment. An additional evaluation of persistence, bioaccumulation, and toxicity (PBT) properties supports the conclusion of no significant environmental risk for 5-FU and CAP.

  2. In-vitro evaluation of the effect of polymer structure on uptake of novel polymer-insulin polyelectrolyte complexes by human epithelial cells.

    PubMed

    Ibie, C; Knott, R; Thompson, C J

    2015-02-01

    The biocompatibility and cellular uptake of polymer, insulin polyelectrolyte complexes (PECs) prepared using polyallylamine-based polymers was evaluated in-vitro using Caco-2 cell monolayers as a predictive model for human small intestinal epithelial cells. Poly(allyl amine) (PAA) and Quaternised PAA (QPAA) were thiolated using either carbodiimide mediated conjugation to N-acetylcysteine (NAC) or reaction with 2-iminothiolane hydrochloride yielding their NAC and 4-thiobutylamidine (TBA) conjugates, respectively. The effect of polymer quaternisation and/or thiolation on the IC50 of PAA was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay carried out on Caco-2 cells (with and without a 24 h recovery period after samples were removed). Uptake of PECs by Caco-2 cells was monitored by microscopy using fluorescein isothiocyanate (FITC) labelled insulin and rhodamine-labelled polymers at polymer:insulin ratios (4:5) after 0.5, 1, 2 and 4 h incubation in growth media (±calcium) and following pre-incubation with insulin. MTT results indicated that quaternisation of PAA was associated with an improvement in IC50 values; cells treated with QPAA (0.001-4 mg mL(-1)) showed no signs of toxicity following a 24 h cell recovery period, while thiolation of QPAA resulted in a decrease in the IC50. Cellular uptake studies showed that within 2-4 h, QPAA and QPAA-TBA insulin PECs were taken up intracellularly, with PECs being localised within the perinuclear area of cells. Further investigation showed that uptake of PECs was unaffected when calcium-free media was used, while presaturating insulin receptors affected the uptake of QPAA, insulin PECs, but not QPAA-TBA PECs. The biocompatibility of PAA and uptake of insulin was improved by both thiol and quaternary substitution.

  3. Longitudinal dependence of the seasonal variations of the topside ionospheric and plasmaspheric electron content: observations and model results

    NASA Astrophysics Data System (ADS)

    Zhang, Man-Lian; Liu, Libo; Ning, Baiqi; Wan, Weixing

    2016-07-01

    Radio signals transmitted from GPS satellite going through the ionization zone above the Earth will be refracted by the ionized components in the ionosphere and the plasmasphere, which would produce additional transfer delay and generate extra errors in satellite navigation and positioning, etc. These errors have strong relation with the total electron content (TEC) along the signal's travelling path. Therefore TEC is one of the most important parameters required by many users for different modern usage purposes. The topside ionospheric and plasmaspheric electron content makes a large contribution to TEC. In the present study, data for the year 2008 of the topside ionospheric and plasmaspheric electron content (PEC) between the height of 800-20200km above the Earth derived from the upward-looking TEC measurements of the precise orbit determination antenna on board the COSMIC low Earth orbit (LEO) satellites to the GPS signals are used to study the longitudinal dependence of the seasonal variations of PEC. A comparison study of the observed PEC with the IZMIRAN_Plas model results is also made. Our study showed that PEC shows different seasonal variations at different longitudinal sectors: for the 240°E-60°E longitudinal sector, PEC shows a strong annual variation with lowest value in the June solstice and highest value in the December solstice months; In contrast, very weak seasonal variations are observed for PEC at 60°E-240°E longitudinal sector; Comparison study showed that this longitudinal dependence feature of the observed PEC's seasonal variation is not well captured by the IZMIRAN_Plas model result. Acknowledgments This research was supported by the National Natural Science Foundation of China (NSFC No. 41274163)

  4. Heme oxygenase-1-mediated autophagy protects against pulmonary endothelial cell death and development of emphysema in cadmium-treated mice

    PubMed Central

    Surolia, Ranu; Karki, Suman; Kim, Hyunki; Yu, Zhihong; Kulkarni, Tejaswini; Mirov, Sergey B.; Carter, A. Brent; Rowe, Steven M.; Matalon, Sadis; Thannickal, Victor J.; Agarwal, Anupam

    2015-01-01

    Pulmonary exposure to cadmium, a major component of cigarette smoke, has a dramatic impact on lung function and the development of emphysema. Cigarette smoke exposure induces heme oxygenase-1 (HO-1), a cytoprotective enzyme. In this study, we employed a truncated mouse model of emphysema by intratracheal instillation of cadmium (CdCl2) solution (0.025% per 1 mg/kg body wt) in HO-1+/+, HO-1−/−, and overexpressing humanized HO-1 bacterial artificial chromosome (hHO-1BAC) mice. We evaluated the role of HO-1 in cadmium-induced emphysema in mice by analyzing histopathology, micro-computed tomography scans, and lung function tests. CdCl2-exposed HO-1−/− mice exhibited more severe emphysema compared with HO-1+/+ or hHO-1BAC mice. Loss of pulmonary endothelial cells (PECs) from the alveolar capillary membrane is recognized to be a target in emphysema. PECs from HO-1+/+, HO-1−/−, and hHO-1BAC were employed to define the underlying molecular mechanism for the protection from emphysema by HO-1. Electron microscopy, expression of autophagic markers (microtubule-associated protein 1B-light chain 3 II, autophagy protein 5, and Beclin1) and apoptotic marker (cleaved caspase 3) suggested induction of autophagy and apoptosis in PECs after CdCl2 treatment. CdCl2-treated HO-1−/− PECs exhibited downregulation of autophagic markers and significantly increased cleaved caspase 3 expression and activity (∼4-fold higher). Moreover, hHO-1BAC PECs demonstrated upregulated autophagy and absence of cleaved caspase 3 expression or activity. Pretreatment of HO-1+/+ PECs with rapamycin induced autophagy and resulted in reduced cell death upon cadmium treatment. Induction of autophagy following CdCl2 treatment was found to be protective from apoptotic cell death. HO-1 induced protective autophagy in PECs and mitigated cadmium-induced emphysema. PMID:26071551

  5. Assessment of hazard metrics for predicting field benthic invertebrate toxicity in the Detroit River, Ontario, Canada.

    PubMed

    McPhedran, Kerry N; Grgicak-Mannion, Alice; Paterson, Gord; Briggs, Ted; Ciborowski, Jan Jh; Haffner, G Douglas; Drouillard, Ken G

    2017-03-01

    Numerical sediment quality guidelines (SQGs) are frequently used to interpret site-specific sediment chemistry and predict potential toxicity to benthic communities. These SQGs are useful for a screening line of evidence (LOE) that can be combined with other LOEs in a full weight of evidence (WOE) assessment of impacted sites. Three common multichemical hazard quotient methods (probable effect concentration [PEC]-Qavg , PEC-Qmet , and PEC-Qsum ) and a novel (hazard score [HZD]) approach were used in conjunction with a consensus-based set of SQGs to evaluate the ability of different scoring metrics to predict the biological effects of sediment contamination under field conditions. Multivariate analyses were first used to categorize river sediments into distinct habitats based on a set of physicochemical parameters to include gravel, low and high flow sand, and silt. For high flow sand and gravel, no significant dose-response relationships between numerically dominant species and various toxicity metric scores were observed. Significant dose-response relationships were observed for chironomid abundances and toxicity scores in low flow sand and silt habitats. For silt habitats, the HZD scoring metric provided the best predictor of chironomid abundances compared to various PEC-Q methods according to goodness-of-fit tests. For low flow sand habitats, PEC-Qsum followed by HZD, provided the best predictors of chironomid abundance. Differences in apparent chironomid toxicity between the 2 habitats suggest habitat-specific differences in chemical bioavailability and indicator taxa sensitivity. Using an IBI method, the HZD, PEC-Qavg , and PEC-Qmet approaches provided reasonable correlations with calculated IBI values in both silt and low flow sand habitats but not for gravel or high flow sands. Computation differences between the various multi-chemical toxicity scoring metrics and how this contributes to bias in different estimates of chemical mixture toxicity scores are

  6. A Killed, Genetically Engineered Derivative of a Wild-Type Extraintestinal Pathogenic E. coli strain is a Vaccine Candidate

    PubMed Central

    Russo, Thomas A.; Beanan, Janet M.; Olson, Ruth; Genagon, Stacy A.; MacDonald, Ulrike; Cope, John J.; Davidson, Bruce A.; Johnston, Brian; Johnson, James R.

    2007-01-01

    Infections due to extraintestinal pathogenic E. coli (ExPEC) result in significant morbidity, mortality and increased healthcare costs. An efficacious vaccine against ExPEC would be desirable. In this report we explore the use of killed-whole E. coli as a vaccine immunogen. Given the diversity of capsule and O-antigens in ExPEC we have hypothesized that alternative targets are viable vaccine candidates. We have also hypothesized that immunization with a genetically engineered strain that is deficient in the capsule and O-antigen will generate a greater immune response against antigens other than the capsular and O-antigen epitopes than a wild-type strain. Lastly, we hypothesize that mucosal immunization with killed E. coli has the potential to generate a significant immune response. In this study we demonstrated that nasal immunization with a formalin-killed ExPEC derivative deficient in capsule and O-antigen results in a significantly greater overall humoral response compared to its wild-type derivative (which demonstrates that capsule and/or the O-antigen impede the development of an optimal humoral immune response) and a significantly greater immune response against non-capsular and O-antigen epitopes. These antibodies also bound to a subset of heterologous ExPEC strains and enhanced neutrophil-mediated bactericidal activity against the homologous and a heterologous strain. Taken together these studies support the concept that formalin-killed genetically engineered ExPEC derivatives are whole cell vaccine candidates to prevent infections due to ExPEC. PMID:17306426

  7. Ab initio MRSDCI study on the low-lying electronic states of the lithium chloride molecule (LiCl)

    NASA Astrophysics Data System (ADS)

    Kurosaki, Yuzuru; Yokoyama, Keiichi

    2012-08-01

    Potential energy curves (PECs) for the low-lying states of the lithium chloride molecule (LiCl) have been calculated using the internally contracted multireference single- and double-excitation configuration interaction (MRSDCI) method with the aug-cc-PVnZ (AVnZ) and aug-cc-PCVnZ (ACVnZ) basis sets, where n = T, Q, and 5. First, we calculate PECs for 7 spin-orbit (SO)-free Λ-S states, X1Σ+, A1Σ+, 3Σ+, 1Π, and 3Π, and then obtain PECs for 13 SO Ω states, X0+, A0+, B0+, 0-(I), 0-(II), 1(I), 1(II), 1(III), and 2, by diagonalizing the matrix of the electronic Hamiltonian plus the Breit-Pauli SO Hamiltonian. The MRSDCI calculations not including core orbital correlation through the single and double excitations are also performed with the AV5Z and ACV5Z basis sets. The Davidson corrections (Q0) are added to both the Λ-S and Ω state energies. Vibrational eigenstates for the obtained X1Σ+ and X0+ PECs are calculated by solving the time-independent Schrödinger equation with the grid method. Thus, the effects of basis set, core orbital correlation, and the Davidson correction on the X1Σ+ and X0+ PECs of LiCl are investigated by comparing the spectroscopic constants calculated from the PECs with one another and with experiment. It is confirmed that to accurately predict the spectroscopic constants we need to include core-electron correlation in the CI expansion and use the basis sets designed to describe core-valence correlation, i.e., ACVnZ. The SO PECs presented in this paper will be of help in the future study of diatomic alkali halide dynamics.

  8. In vivo bioactivity of rhBMP-2 delivered with novel polyelectrolyte complexation shells assembled on an alginate microbead core template.

    PubMed

    Abbah, Sunny-Akogwu; Liu, Jing; Lam, Raymond W M; Goh, James C H; Wong, Hee-Kit

    2012-09-10

    Electrostatic interactions between polycations and polyanions are being explored to fabricate polyelectrolyte complexes (PEC) that could entrap and regulate the release of a wide range of biomolecules. Here, we report the in vivo application of PEC shells fabricated from three different polycations: poly-l-ornithine (PLO), poly-l-arginine (PLA) and DEAE-dextran (DEAE-D) to condense heparin on the surface of alginate microbeads and further control the delivery of recombinant human bone morphogenetic protein 2 (rhBMP-2) in spinal fusion application. We observed large differences in the behavior of PEC shells fabricated from the cationic polyamino acids (PLO and PLA) when compared to the cationic polysaccharide, DEAE-D. Whereas DEAE-D-based PEC shells eroded and released rhBMP-2 over 2 days in vitro, PLO- and PLA-based shells retained at least 60% of loaded rhBMP-2 after 3 weeks of incubation in phosphate-buffered saline. In vivo implantation in a rat model of posterolateral spinal fusion revealed robust bone formation in the PLO- and PLA-based PEC shell groups. This resulted in a significantly enhanced mechanical stability of the fused segments. However, bone induction and biomechanical stability of spine segments implanted with DEAE-D-based carriers were significantly inferior to both PLO- and PLA-based PEC shell groups (p<0.01). From these results, we conclude that PEC shells incorporating native heparin could be used for growth factor delivery in functional bone tissue engineering application and that PLA- and PLO-based complexes could represent superior options to DEAE-D for loading and in vivo delivery of bioactive BMP-2 in this approach.

  9. Heme oxygenase-1-mediated autophagy protects against pulmonary endothelial cell death and development of emphysema in cadmium-treated mice.

    PubMed

    Surolia, Ranu; Karki, Suman; Kim, Hyunki; Yu, Zhihong; Kulkarni, Tejaswini; Mirov, Sergey B; Carter, A Brent; Rowe, Steven M; Matalon, Sadis; Thannickal, Victor J; Agarwal, Anupam; Antony, Veena B

    2015-08-01

    Pulmonary exposure to cadmium, a major component of cigarette smoke, has a dramatic impact on lung function and the development of emphysema. Cigarette smoke exposure induces heme oxygenase-1 (HO-1), a cytoprotective enzyme. In this study, we employed a truncated mouse model of emphysema by intratracheal instillation of cadmium (CdCl2) solution (0.025% per 1 mg/kg body wt) in HO-1(+/+), HO-1(-/-), and overexpressing humanized HO-1 bacterial artificial chromosome (hHO-1BAC) mice. We evaluated the role of HO-1 in cadmium-induced emphysema in mice by analyzing histopathology, micro-computed tomography scans, and lung function tests. CdCl2-exposed HO-1(-/-) mice exhibited more severe emphysema compared with HO-1(+/+) or hHO-1BAC mice. Loss of pulmonary endothelial cells (PECs) from the alveolar capillary membrane is recognized to be a target in emphysema. PECs from HO-1(+/+), HO-1(-/-), and hHO-1BAC were employed to define the underlying molecular mechanism for the protection from emphysema by HO-1. Electron microscopy, expression of autophagic markers (microtubule-associated protein 1B-light chain 3 II, autophagy protein 5, and Beclin1) and apoptotic marker (cleaved caspase 3) suggested induction of autophagy and apoptosis in PECs after CdCl2 treatment. CdCl2-treated HO-1(-/-) PECs exhibited downregulation of autophagic markers and significantly increased cleaved caspase 3 expression and activity (∼4-fold higher). Moreover, hHO-1BAC PECs demonstrated upregulated autophagy and absence of cleaved caspase 3 expression or activity. Pretreatment of HO-1(+/+) PECs with rapamycin induced autophagy and resulted in reduced cell death upon cadmium treatment. Induction of autophagy following CdCl2 treatment was found to be protective from apoptotic cell death. HO-1 induced protective autophagy in PECs and mitigated cadmium-induced emphysema.

  10. Frequency of hepatitis E virus, rotavirus and porcine enteric calicivirus at various stages of pork carcass processing in two pork processing plants.

    PubMed

    Jones, Tineke H; Muehlhauser, Victoria

    2017-10-16

    Hepatitis E virus (HEV), rotavirus (RV), and porcine enteric calicivirus (PEC) infections are common in swine and raises concerns about the potential for zoonotic transmission through undercooked meat products. Enteric viruses can potentially contaminate carcasses during meat processing operations. There is a lack of information on the prevalence and control of enteric viruses in the pork processing chain. This study compared the incidence and levels of contamination of hog carcasses with HEV, RV and PEC at different stages of the dressing process. A total of 1000 swabs were collected from 2 pork processing plants on 10 separate occasions over the span of a year. The samples were obtained from random sites on hog carcasses at 4 dressing stages (plant A: bleeding, dehairing, pasteurization, and evisceration; plant B: bleeding, skinning, evisceration, and washing) and from meat cuts. Numbers of genome copies (gc) of HEV, RV and PEC were determined by RT-qPCR. RV and PEC were detected in 100%, and 18% of samples, respectively, after bleeding for plant A and in 98%, and 36% of samples, respectively, after bleeding for plant B. After evisceration, RV and PEC were detected in 21% and 3% of samples, respectively, for plant A and in 1%, and 0% of samples, respectively for plant B. RV and PEC were detected on 1%, and 5% of pork cuts, respectively, for plant A and on 0%, and 0% of pork cuts, respectively, for plant B. HEV was not detected in any pork carcass or retail pork samples from plants A or B. The frequency of PEC and RV on pork is progressively reduced along the pork processing chain but the viruses were not completely eliminated. The findings suggest that consumers could be at risk when consuming undercooked meat contaminated with pathogenic enteric viruses. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

  11. A New Water-Soluble Nanomicelle Formed through Self-Assembly of Pectin-Curcumin Conjugates: Preparation, Characterization, and Anticancer Activity Evaluation.

    PubMed

    Bai, Feng; Diao, Jiajing; Wang, Ying; Sun, Shixin; Zhang, Hongmei; Liu, Yunyun; Wang, Yanqing; Cao, Jian

    2017-08-16

    Curcumin is a dominating active component of Curcuma longa and has been studied widely because of its prominent biological activities. The extremely low aqueous solubility, stability, and bioavailability of curcumin limit its application in the field of medicine. In this study, we developed pectin-curcumin (PEC-CCM) conjugates that could self-assemble water-soluble nanomicelles in aqueous solution. The structure of PEC-CCM conjugates was characterized by ultraviolet-visible spectra, fluorescence spectra, Fourier transform infrared spectroscopy, and (1)H nuclear magnetic resonance spectroscopy. The thermal property of PEC-CCM conjugates was investigated by thermogravimetric analysis. It was found that PEC-CCM conjugates had formed nanomicelles in aqueous medium via self-assembly. These nanomicelles were observed as small spheres or ellipsoids and aggregated with a size range of 70-190 nm by transmission electron microscopy analysis. In a solution of nanomicelles, the stability of curcumin was improved, and its antioxidant property was preserved. The anticancer activity of PEC-CCM conjugates was quantified by the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay using a hepatic cancer cell line (HepG2), a breast cancer cell line (MCF-7), a cervical cancer cell line (HeLa), and a human normal kidney cell line (293A). It was found that the curcumin of PEC-CCM conjugates had a more significant inhibitory effect on cancer cells and was less cytotoxic to normal cells than free curcumin was. PEC-CCM conjugates have great potential for some food and pharmaceutical applications.

  12. Extraintestinal Pathogenic and Antimicrobial-Resistant Escherichia coli Contamination of 56 Public Restrooms in the Greater Minneapolis-St. Paul Metropolitan Area

    PubMed Central

    Owens, Kris; Gajewski, Abby; Clabots, Connie; Johnston, Brian; Thuras, Paul; Kuskowski, Michael A.; Johnson, James R.

    2015-01-01

    How extraintestinal pathogenic Escherichia coli (ExPEC) and antimicrobial-resistant E. coli disseminate through the population is undefined. We studied public restrooms for contamination with E. coli and ExPEC in relation to source and extensively characterized the E. coli isolates. For this, we cultured 1,120 environmental samples from 56 public restrooms in 33 establishments (obtained from 10 cities in the greater Minneapolis-St. Paul, MN, metropolitan area in 2003) for E. coli and compared ecological data with culture results. Isolates underwent virulence genotyping, phylotyping, clonal typing, pulsed-field gel electrophoresis (PFGE), and disk diffusion antimicrobial susceptibility testing. Overall, 168 samples (15% from 89% of restrooms) fluoresced, indicating presumptive E. coli: 25 samples (2.2% from 32% of restrooms) yielded E. coli isolates, and 10 samples (0.9% from 16% of restrooms) contained ExPEC. Restroom category and cleanliness level significantly predicted only fluorescence, gender predicted fluorescence and E. coli, and feces-like material and toilet-associated sites predicted all three endpoints. Of the 25 E. coli isolates, 7 (28%) were from phylogenetic group B2(virulence-associated), and 8 (32%) were ExPEC. ExPEC isolates more commonly represented group B2 (50% versus 18%) and had significantly higher virulence gene scores than non-ExPEC isolates. Six isolates (24%) exhibited ≥3-class antibiotic resistance, 10 (40%) represented classic human-associated sequence types, and one closely resembled reference human clinical isolates by pulsed-field gel electrophoresis. Thus, E. coli, ExPEC, and antimicrobial-resistant E. coli sporadically contaminate public restrooms, in ways corresponding with restroom characteristics and within-restroom sites. Such restroom-source E. coli strains likely reflect human fecal contamination, may pose a health threat, and may contribute to population-wide dissemination of such strains. PMID:25911488

  13. Combining Quantitative Genetic Footprinting and Trait Enrichment Analysis to Identify Fitness Determinants of a Bacterial Pathogen

    PubMed Central

    Wiles, Travis J.; Norton, J. Paul; Russell, Colin W.; Dalley, Brian K.; Fischer, Kael F.; Mulvey, Matthew A.

    2013-01-01

    Strains of Extraintestinal Pathogenic Escherichia c oli (ExPEC) exhibit an array of virulence strategies and are a major cause of urinary tract infections, sepsis and meningitis. Efforts to understand ExPEC pathogenesis are challenged by the high degree of genetic and phenotypic variation that exists among isolates. Determining which virulence traits are widespread and which are strain-specific will greatly benefit the design of more effective therapies. Towards this goal, we utilized a quantitative genetic footprinting technique known as transposon insertion sequencing (Tn-seq) in conjunction with comparative pathogenomics to functionally dissect the genetic repertoire of a reference ExPEC isolate. Using Tn-seq and high-throughput zebrafish infection models, we tracked changes in the abundance of ExPEC variants within saturated transposon mutant libraries following selection within distinct host niches. Nine hundred and seventy bacterial genes (18% of the genome) were found to promote pathogen fitness in either a niche-dependent or independent manner. To identify genes with the highest therapeutic and diagnostic potential, a novel Trait Enrichment Analysis (TEA) algorithm was developed to ascertain the phylogenetic distribution of candidate genes. TEA revealed that a significant portion of the 970 genes identified by Tn-seq have homologues more often contained within the genomes of ExPEC and other known pathogens, which, as suggested by the first axiom of molecular Koch's postulates, is considered to be a key feature of true virulence determinants. Three of these Tn-seq-derived pathogen-associated genes—a transcriptional repressor, a putative metalloendopeptidase toxin and a hypothetical DNA binding protein—were deleted and shown to independently affect ExPEC fitness in zebrafish and mouse models of infection. Together, the approaches and observations reported herein provide a resource for future pathogenomics-based research and highlight the diversity of

  14. Escherichia coli isolates from commercial chicken meat and eggs cause sepsis, meningitis and urinary tract infection in rodent models of human infections.

    PubMed

    Mellata, M; Johnson, J R; Curtiss, R

    2017-07-13

    The zoonotic potential of Escherichia coli from chicken-source food products is important to define for public health purposes. Previously, genotypic and phenotypic screening of E. coli isolates from commercial chicken meat and shell eggs identified some E. coli strains that by molecular criteria resembled human-source extraintestinal pathogenic E. coli (ExPEC). Here, to clarify the zoonotic risk of such chicken-source E. coli, we compared selected E. coli isolates from chicken meat and eggs, stratified by molecularly defined ExPEC status, to human-source ExPEC and to laboratory E. coli for virulence in rodent models of sepsis, meningitis and UTI, and evaluated whether specific bacterial characteristics predict experimental virulence. Multiple chicken-source E. coli resembled human-source ExPEC in their ability to cause one or multiple different ExPEC-associated infections. Swimming ability corresponded with urovirulence, K1 capsule corresponded with ability to cause neonatal meningitis, and biofilm formation in urine corresponded with ability to cause sepsis. In contrast, molecularly defined ExPEC status and individual genotypic traits were uncorrelated with ability to cause sepsis, and neither complement sensitivity nor growth in human urine corresponded with virulence in any infection model. These findings establish that chicken-derived food products contain E. coli strains that, in rodent models of multiple human-associated ExPEC infections, are able to cause disease comparably to human-source E. coli clinical isolates, which suggests that they may pose a significant food safety threat. Further study is needed to define the level of risk they pose to human health, which if appreciable would justify efforts to monitor for and reduce or eliminate them. © 2017 Blackwell Verlag GmbH.

  15. Changes in glomerular parietal epithelial cells in mouse kidneys with advanced age

    PubMed Central

    Roeder, Sebastian S.; Stefanska, Ania; Eng, Diana G.; Kaverina, Natalya; Sunseri, Maria W.; McNicholas, Bairbre A.; Rabinovitch, Peter; Engel, Felix B.; Daniel, Christoph; Amann, Kerstin; Lichtnekert, Julia; Pippin, Jeffrey W.

    2015-01-01

    Kidney aging is accompanied by characteristic changes in the glomerulus, but little is known about the effect of aging on glomerular parietal epithelial cells (PECs), nor if the characteristic glomerular changes in humans and rats also occur in very old mice. Accordingly, a descriptive analysis was undertaken in 27-mo-old C57B6 mice, considered advanced age. PEC density was significantly lower in older mice compared with young mice (aged 3 mo), and the decrease was more pronounced in juxtamedullary glomeruli compared with outer cortical glomeruli. In addition to segmental and global glomerulosclerosis in older mice, staining for matrix proteins collagen type IV and heparan sulfate proteoglycan were markedly increased in Bowman's capsules of older mouse glomeruli, consistent with increased extracellular matrix production by PECs. De novo staining for CD44, a marker of activated and profibrotic PECs, was significantly increased in aged glomeruli. CD44 staining was more pronounced in the juxtamedullary region and colocalized with phosphorylated ERK. Additionally, a subset of aged PECs de novo expressed the epithelial-to-mesenchymal transition markers α-smooth muscle and vimentin, with no changes in epithelial-to-mesenchymal transition markers E-cadherin and β-catenin. The mural cell markers neural/glial antigen 2, PDGF receptor-β, and CD146 as well as Notch 3 were also substantially increased in aged PECs. These data show that mice can be used to better understand the aging kidney and that PECs undergo substantial changes, especially in juxtamedullary glomeruli, that may participate in the overall decline in glomerular structure and function with advancing age. PMID:26017974

  16. Cast adhesive polyelectrolyte complex particle films of unmodified or maltose-modified poly(ethyleneimine) and cellulose sulphate: fabrication, film stability and retarded release of zoledronate.

    PubMed

    Torger, Bernhard; Vehlow, David; Urban, Birgit; Salem, Samaa; Appelhans, Dietmar; Müller, Martin

    2013-12-01

    The bone therapeutic drug zoledronate (ZOL) was loaded at and released by polyelectrolyte complex (PEC) particle films composed of either pure poly(ethyleneimine) (PEI) or maltose-modified poly(ethyleneimine) (PEI-M) and oppositely charged cellulose sulfate attached to model germanium (Ge) substrates by solution casting. Dispersions of colloidally stable polyelectrolyte complex (PEC) particles in the size range 11-141 nm were obtained by mixing PEI or PEI-M, CS and ZOL in defined stoichiometric ratios. TRANS-FTIR spectroscopy was used to determine the stability of the PEC films against detachment, in-situ-ATR-FTIR spectroscopy for the ZOL loss in the PEC film and UV-VIS spectroscopy for the ZOL enrichment of the release medium. Films of casted ZOL/CS/PEI-M or ZOL/CS/PEI particles were stable in contact to water, while films of the pure drug (ZOL) and of the binary systems ZOL/PEI-M or ZOL/PEI were not stable against detachment. Retarded releases of ZOL from various PEC films compared to the pure drug film were observed. The molecular weight of PEI showed a considerable effect on the initial burst (IB) of ZOL. No significant effect of the maltose modification of PEI-25 K on IB could be found. Generally, after one day the ZOL release process was finished for all measured ZOL/PEC samples and residual amounts of 0-30% were obtained. Surface adhesive drug loaded PEC particles are promising drug delivery systems to supply and release a defined amount of bone therapeutics and to functionalize bone substitution materials.

  17. Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

    NASA Astrophysics Data System (ADS)

    Barati Ghahfarokhi, Reza

    Guar-based polymer gels are used in the oil and gas industry to viscosify fluids used in hydraulic fracturing of production wells, in order to reduce leak-off of fluids and pressure, and improve the transport of proppants. After fracturing, the gel and associated filter cake must be degraded to very low viscosities using breakers to recover the hydraulic conductivity of the well. Enzymes are widely used to achieve this but injecting high concentrations of enzyme may result in premature degradation, or failure to gel; denaturation of enzymes at alkaline pH and high temperature conditions can also limit their applicability. In this study, application of polyelectrolyte nanoparticles for entrapping, carrying, releasing and protecting enzymes for fracturing fluids was examined. The objective of this research is to develop nano-sized carriers capable of carrying the enzymes to the filter cake, delaying the release of enzyme and protecting the enzyme against pH and temperature conditions inhospitable to native enzyme. Polyethylenimine-dextran sulfate (PEI-DS) polyelectrolyte complexes (PECs) were used to entrap two enzymes commonly used in the oil industry in order to obtain delayed release and to protect the enzyme from conditions inhospitable to native enzyme. Stability and reproducibility of PEC nanoparticles was assured over time. An activity measurement method was used to measure the entrapment efficiency of enzyme using PEC nanoparticles. This method was confirmed using a concentration measurement method (SDS-PAGE). Entrapment efficiencies of pectinase and a commercial high-temperature enzyme mixture in polyelectrolyte complex nanoparticles were maximized. Degradation, as revealed by reduction in viscoelastic moduli of borate-crosslinked hydroxypropyl guar (HPG) gel by commercial enzyme loaded in polyelectrolyte nanoparticles, was delayed, compared to equivalent systems where the enzyme mixture was not entrapped. This indicates that PEC nanoparticles delay the

  18. Unveiling the photoelectrocatalytic inactivation mechanism of Escherichia coli: Convincing evidence from responses of parent and anti-oxidation single gene knockout mutants.

    PubMed

    Sun, Hongwei; Li, Guiying; An, Taicheng; Zhao, Huijun; Wong, Po Keung

    2016-01-01

    This study investigated photoelectrocatalytic (PEC) inactivation mechanism of bacteria using parental Escherichia coli (E. coli) BW25113 and its isogenic mutants deficient in catalase HPI (katG(-), JW3914-1) and Mn-SOD (sodA(-), JW3879-1). BW25113 in the mid-log phase was less susceptible to PEC inactivation than those in early-log and stationary phases, consistent with the peak activities of catalase and superoxide dismutase (SOD) at mid-log phase (30.6 and 13.0 Unit/ml/OD600). For different strains all in mid-log phase, PEC inactivation efficiency followed the order katG(-) > sodA(-) > BW25113, with the duration of 60, 60 and 90 min for complete inactivation of ∼2 × 10(7) CFU mL(-1) bacteria, respectively. Correspondingly, catalase and SOD levels of BW25113 were also higher than the mutants by 5.9 and 11.7 Unit/mL/OD600, respectively. Reactive oxygen species (ROSs) concentrations in PEC systems revealed that the inactivation performance coincided with H2O2 levels, rather than OH. Moreover, pre-incubation with H2O2 elevated catalase activities and PEC inactivation resistance of BW25113 were positively correlated. The above results indicated that H2O2 was the dominant PEC generated bactericide, and anti-oxidative enzymes especially catalase contributed greatly to the bacterial PEC resistance capacity. Further tests revealed that PEC treatment raised the intracellular ROSs concentration by more than 3 times, due to the permeated H2O2 and its intracellular derivative, OH. However, oxidative stress response of E. coli, such as increased catalase or SOD were not observed, perhaps because the ROSs overwhelmed the bacterial protective capacity. The accumulated ROSs subsequently caused oxidative damages to E. coli cells, including membrane damage, K(+) leakage, and protein oxidation. Compared with BW25113, the mutants experienced damages earlier and at higher levels, confirming the essential roles of catalase and SOD in the bacterial PEC resistance.

  19. The role of the domain size and titanium dopant in nanocrystalline hematite thin films for water photolysis

    NASA Astrophysics Data System (ADS)

    Yan, Danhua; Tao, Jing; Kisslinger, Kim; Cen, Jiajie; Wu, Qiyuan; Orlov, Alexander; Liu, Mingzhao

    2015-11-01

    Here we develop a novel technique for preparing high quality Ti-doped hematite thin films for photoelectrochemical (PEC) water splitting, through sputtering deposition of metallic iron films from an iron target embedded with titanium (dopants) pellets, followed by a thermal oxidation step that turns the metal films into doped hematite. It is found that the hematite domain size can be tuned from ~10 nm to over 100 nm by adjusting the sputtering atmosphere from more oxidative to mostly inert. The better crystallinity at a larger domain size ensures excellent PEC water splitting performance, leading to record high photocurrent from pure planar hematite thin films on FTO substrates. Titanium doping further enhances the PEC performance of hematite photoanodes. The photocurrent is improved by 50%, with a titanium dopant concentration as low as 0.5 atom%. It is also found that the role of the titanium dopant in improving the PEC performance is not apparently related to the films' electrical conductivity which had been widely believed, but is more likely due to the passivation of surface defects by the titanium dopants.Here we develop a novel technique for preparing high quality Ti-doped hematite thin films for photoelectrochemical (PEC) water splitting, through sputtering deposition of metallic iron films from an iron target embedded with titanium (dopants) pellets, followed by a thermal oxidation step that turns the metal films into doped hematite. It is found that the hematite domain size can be tuned from ~10 nm to over 100 nm by adjusting the sputtering atmosphere from more oxidative to mostly inert. The better crystallinity at a larger domain size ensures excellent PEC water splitting performance, leading to record high photocurrent from pure planar hematite thin films on FTO substrates. Titanium doping further enhances the PEC performance of hematite photoanodes. The photocurrent is improved by 50%, with a titanium dopant concentration as low as 0.5 atom%. It is

  20. Comparative Genomics of Escherichia coli Isolated from Skin and Soft Tissue and Other Extraintestinal Infections.

    PubMed

    Ranjan, Amit; Shaik, Sabiha; Nandanwar, Nishant; Hussain, Arif; Tiwari, Sumeet K; Semmler, Torsten; Jadhav, Savita; Wieler, Lothar H; Alam, Munirul; Colwell, Rita R; Ahmed, Niyaz

    2017-08-15

    Escherichia coli, an intestinal Gram-negative bacterium, has been shown to be associated with a variety of diseases in addition to intestinal infections, such as urinary tract infections (UTIs), meningitis in neonates, septicemia, skin and soft tissue infections (SSTIs), and colisepticemia. Thus, for nonintestinal infections, it is categorized as extraintestinal pathogenic E. coli (ExPEC). It is also an opportunistic pathogen, causing cross infections, notably as an agent of zoonotic diseases. However, comparative genomic data providing functional and genetic coordinates for ExPEC strains associated with these different types of infections have not proven conclusive. In the study reported here, ExPEC E. coli isolated from SSTIs was characterized, including virulence and drug resistance profiles, and compared with isolates from patients suffering either pyelonephritis or septicemia. Results revealed that the majority of the isolates belonged to two pathogenic phylogroups, B2 and D. Approximately 67% of the isolates were multidrug resistant (MDR), with 85% producing extended-spectrum beta-lactamase (ESBL) and 6% producing metallo-beta-lactamase (MBL). The blaCTX-M-15 genotype was observed in at least 70% of the E. coli isolates in each category, conferring resistance to an extended range of beta-lactam antibiotics. Whole-genome sequencing and comparative genomics of the ExPEC isolates revealed that two of the four isolates from SSTIs, NA633 and NA643, belong to pandemic sequence type ST131, whereas functional characteristics of three of the ExPEC pathotypes revealed that they had equal capabilities to form biofilm and were resistant to human serum. Overall, the isolates from a variety of ExPEC infections demonstrated similar resistomes and virulomes and did not display any disease-specific functional or genetic coordinates.IMPORTANCE Infections caused by extraintestinal pathogenic E. coli (ExPEC) are of global concern as they result in significant costs to health

  1. Similarly Lethal Strains of Extraintestinal Pathogenic Escherichia coli Trigger Markedly Diverse Host Responses in a Zebrafish Model of Sepsis

    PubMed Central

    Barber, Amelia E.; Fleming, Brittany A.

    2016-01-01

    ABSTRACT In individuals with sepsis, the infecting microbes are commonly viewed as generic inducers of inflammation while the host background is considered the primary variable affecting disease progression and outcome. To study the effects of bacterial strain differences on the maladaptive immune responses that are induced during sepsis, we employed a novel zebrafish embryo infection model using extraintestinal pathogenic Escherichia coli (ExPEC) isolates. These genetically diverse pathogens are a leading cause of sepsis and are becoming increasingly dangerous because of the rise of multidrug-resistant strains. Zebrafish infected with ExPEC isolates exhibit many of the pathophysiological features seen in septic human patients, including dysregulated inflammatory responses (cytokine storms), tachycardia, endothelial leakage, and progressive edema. However, only a limited subset of ExPEC isolates can trigger a sepsis-like state and death of the host when introduced into the bloodstream. Mirroring the situation in human patients, antibiotic therapy reduced ExPEC titers and improved host survival rates but was only effective within limited time frames that varied, depending on the infecting pathogen. Intriguingly, we find that phylogenetically distant but similarly lethal ExPEC isolates can stimulate markedly different host transcriptional responses, including disparate levels of inflammatory mediators. These differences correlate with the amounts of bacterial flagellin expression during infection, as well as differential activation of Toll-like receptor 5 by discrete flagellar serotypes. Altogether, this work establishes zebrafish as a relevant model of key aspects of human sepsis and highlights the ability of genetically distinct ExPEC isolates to induce divergent host responses independently of baseline host attributes. IMPORTANCE Sepsis is a life-threatening systemic inflammatory condition that is initiated by the presence of microorganisms in the bloodstream. In

  2. Plasmon-induced photoelectrochemical biosensor for in situ real-time measurement of biotin-streptavidin binding kinetics under visible light irradiation.

    PubMed

    Guo, Jingchun; Oshikiri, Tomoya; Ueno, Kosei; Shi, Xu; Misawa, Hiroaki

    2017-03-08

    We developed a localized surface plasmon-induced visible light-responsive photoelectrochemical (PEC) biosensor using a titanium dioxide (TiO2) photoelectrode loaded with gold nanoislands (AuNIs) for in situ real-time measurement of biotin-streptavidin association. As a proof of concept, self-assembled thiol-terminated biotin molecules bound on a AuNIs/TiO2 photoelectrode were successfully utilized to explore the photocurrent response to streptavidin-modified gold nanoparticle (STA-AuNP) solutions. This plasmon-induced PEC biosensor is simple and easy to miniaturize. Additionally, the PEC biosensor achieves highly sensitive measurements under only visible light irradiation and prevents the UV-induced damage of samples. Furthermore, a novel approach has been proposed to realize the real-time monitoring of biotin-STA binding affinities and kinetics by analyzing the PEC sensing characteristics. This PEC biosensor and novel analysis method could provide a new approach for the specific electrical detection and real-time kinetic measurements for clinical diagnostics and drug development.

  3. Limiting photocurrent analysis of a wide channel photoelectrochemical flow reactor

    NASA Astrophysics Data System (ADS)

    Davis, Jonathan T.; Esposito, Daniel V.

    2017-03-01

    The development of efficient and scalable photoelectrochemical (PEC) reactors is of great importance for the eventual commercialization of solar fuels technology. In this study, we systematically explore the influence of convective mass transport and light intensity on the performance of a 3D-printed PEC flow cell reactor based on a wide channel, parallel plate geometry. Using this design, the limiting current density generated from the hydrogen evolution reaction at a p-Si metal-insulator-semiconductor (MIS) photocathode was investigated under varied reactant concentration, fluid velocity, and light intensity. Additionally, a simple model is introduced to predict the range of operating conditions (reactant concentration, light intensity, fluid velocity) for which the photocurrent generated in a parallel plate PEC flow cell is limited by light absorption or mass transport. This model can serve as a useful guide for the design and operation of wide-channel PEC flow reactors. The results of this study have important implications for PEC reactors operating in electrolytes with dilute reactant concentrations and/or under high light intensities where high fluid velocities are required in order to avoid operation in the mass transport-limited regime.

  4. Achieving Highly Efficient Photoelectrochemical Water Oxidation with a TiCl4 Treated 3D Antimony-Doped SnO2 Macropore/Branched α-Fe2O3 Nanorod Heterojunction Photoanode.

    PubMed

    Xu, Yang-Fan; Rao, Hua-Shang; Chen, Bai-Xue; Lin, Ying; Chen, Hong-Yan; Kuang, Dai-Bin; Su, Cheng-Yong

    2015-07-01

    Utilizing photoelectrochemical (PEC) cells to directly collecting solar energy into chemical fuels (e.g., H2 via water splitting) is a promising way to tackle the energy challenge. α-Fe2O3 has emerged as a desirable photoanode material in a PEC cell due to its wide spectrum absorption range, chemical stability, and earth abundant component. However, the short excited state lifetime, poor minority charge carrier mobility, and long light penetration depth hamper its application. Recently, the elegantly designed hierarchical macroporous composite nanomaterial has emerged as a strong candidate for photoelectrical applications. Here, a novel 3D antimony-doped SnO2 (ATO) macroporous structure is demonstrated as a transparent conducting scaffold to load 1D hematite nanorod to form a composite material for efficient PEC water splitting. An enormous enhancement in PEC performance is found in the 3D electrode compared to the controlled planar one, due to the outstanding light harvesting and charge transport. A facile and simple TiCl4 treatment further introduces the Ti doping into the hematite while simultaneously forming a passivation layer to eliminate adverse reactions. The results indicate that the structural design and nanoengineering are an effective strategy to boost the PEC performance in order to bring more potential devices into practical use.

  5. Light Harvesting Proteins for Solar Fuel Generation in Bioengineered Photoelectrochemical Cells

    PubMed Central

    Ihssen, Julian; Braun, Artur; Faccio, Greta; Gajda-Schrantz, Krisztina; Thöny-Meyer, Linda

    2014-01-01

    The sun is the primary energy source of our planet and potentially can supply all societies with more than just their basic energy needs. Demand of electric energy can be satisfied with photovoltaics, however the global demand for fuels is even higher. The direct way to produce the solar fuel hydrogen is by water splitting in photoelectrochemical (PEC) cells, an artificial mimic of photosynthesis. There is currently strong resurging interest for solar fuels produced by PEC cells, but some fundamental technological problems need to be solved to make PEC water splitting an economic, competitive alternative. One of the problems is to provide a low cost, high performing water oxidizing and oxygen evolving photoanode in an environmentally benign setting. Hematite, α-Fe2O3, satisfies many requirements for a good PEC photoanode, but its efficiency is insufficient in its pristine form. A promising strategy for enhancing photocurrent density takes advantage of photosynthetic proteins. In this paper we give an overview of how electrode surfaces in general and hematite photoanodes in particular can be functionalized with light harvesting proteins. Specifically, we demonstrate how low-cost biomaterials such as cyanobacterial phycocyanin and enzymatically produced melanin increase the overall performance of virtually no-cost metal oxide photoanodes in a PEC system. The implementation of biomaterials changes the overall nature of the photoanode assembly in a way that aggressive alkaline electrolytes such as concentrated KOH are not required anymore. Rather, a more environmentally benign and pH neutral electrolyte can be used. PMID:24678669

  6. Photoelectrochemical hydrogen production on α-Fe2O3 (0001): insights from theory and experiments.

    PubMed

    Baltrusaitis, Jonas; Hu, Yong-Sheng; McFarland, Eric W; Hellman, Anders

    2014-01-01

    The photoelectrochemical (PEC) decomposition of organic compounds in wastewater is investigated by using quantum chemical (DFT) methods to evaluate alternatives to water splitting for the production of renewable and sustainable hydrogen. Methanol is used as a model organic species for the theoretical evaluations of electrolysis on the surface of the widely available semiconductor hematite, α-Fe2 O3 , a widely studied photocatalyst. Three different α-Fe2 O3 surface terminations were investigated, including the predominant surface found in aqueous electrolytes, (OH)3 R. The PEC oxidation of methanol is energetically downhill, producing CO2 and protons. The protons are reduced to hydrogen on the cathode. Experimental PEC measurements were also performed for several polyalcoholic compounds, glycerol, erythritol, and xylitol, on α-Fe2 O3 as the photocatalyst and showed high incident-photon-to-current-efficiencies (IPCE) that were much greater than those of water splitting. Interestingly, high IPCEs were observed for hydrogen production from polyalcohols in the absence of any applied bias, which was not thought to be possible on hematite. These results support the potential application of PEC for hydrogen production by using widely available hematite for the PEC oxidation of selected components of organic wastewater present in large quantities from anthropogenic and industrial sources. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Efficient photoelectrochemical water splitting with ultrathin films of hematite on three-dimensional nanophotonic structures.

    PubMed

    Qiu, Yongcai; Leung, Siu-Fung; Zhang, Qianpeng; Hua, Bo; Lin, Qingfeng; Wei, Zhanhua; Tsui, Kwong-Hoi; Zhang, Yuegang; Yang, Shihe; Fan, Zhiyong

    2014-01-01

    Photoelectrochemical (PEC) solar water splitting represents a clean and sustainable approach for hydrogen (H2) production and substantial research are being performed to improve the conversion efficiency. Hematite (α-Fe2O3) is considered as a promising candidate for PEC water splitting due to its chemical stability, appropriate band structure, and abundance. However, PEC performance based on hematite is hindered by the short hole diffusion length that put a constraint on the active layer thickness and its light absorption capability. In this work, we have designed and fabricated novel PEC device structure with ultrathin hematite film deposited on three-dimensional nanophotonic structure. In this fashion, the nanophotonic structures can largely improve the light absorption in the ultrathin active materials. In addition, they also provide large surface area to accommodate the slow surface water oxidation process. As the result, high current density of 3.05 mA cm(-2) at 1.23 V with respect to the reversible hydrogen electrode (RHE) has been achieved on such nanophotonic structure, which is about three times of that for a planar photoelectrode. More importantly, our systematic analysis with experiments and modeling revealed that the design of high performance PEC devices needs to consider not only total optical absorption, but also the absorption profile in the active material, in addition to electrode surface area and carrier collection.

  8. Achieving Highly Efficient Photoelectrochemical Water Oxidation with a TiCl4 Treated 3D Antimony‐Doped SnO2 Macropore/Branched α‐Fe2O3 Nanorod Heterojunction Photoanode

    PubMed Central

    Xu, Yang‐Fan; Rao, Hua‐Shang; Chen, Bai‐Xue; Lin, Ying; Chen, Hong‐Yan; Su, Cheng‐Yong

    2015-01-01

    Utilizing photoelectrochemical (PEC) cells to directly collecting solar energy into chemical fuels (e.g., H2 via water splitting) is a promising way to tackle the energy challenge. α‐Fe2O3 has emerged as a desirable photoanode material in a PEC cell due to its wide spectrum absorption range, chemical stability, and earth abundant component. However, the short excited state lifetime, poor minority charge carrier mobility, and long light penetration depth hamper its application. Recently, the elegantly designed hierarchical macroporous composite nanomaterial has emerged as a strong candidate for photoelectrical applications. Here, a novel 3D antimony‐doped SnO2 (ATO) macroporous structure is demonstrated as a transparent conducting scaffold to load 1D hematite nanorod to form a composite material for efficient PEC water splitting. An enormous enhancement in PEC performance is found in the 3D electrode compared to the controlled planar one, due to the outstanding light harvesting and charge transport. A facile and simple TiCl4 treatment further introduces the Ti doping into the hematite while simultaneously forming a passivation layer to eliminate adverse reactions. The results indicate that the structural design and nanoengineering are an effective strategy to boost the PEC performance in order to bring more potential devices into practical use. PMID:27980959

  9. An Overview of Two-Component Signal Transduction Systems Implicated in Extra-Intestinal Pathogenic E. coli Infections.

    PubMed

    Breland, Erin J; Eberly, Allison R; Hadjifrangiskou, Maria

    2017-01-01

    Extra-intestinal pathogenic E. coli (ExPEC) infections are common in mammals and birds. The predominant ExPEC types are avian pathogenic E. coli (APEC), neonatal meningitis causing E. coli/meningitis associated E. coli (NMEC/MAEC), and uropathogenic E. coli (UPEC). Many reviews have described current knowledge on ExPEC infection strategies and virulence factors, especially for UPEC. However, surprisingly little has been reported on the regulatory modules that have been identified as critical in ExPEC pathogenesis. Two-component systems (TCSs) comprise the predominant method by which bacteria respond to changing environments and play significant roles in modulating bacterial fitness in diverse niches. Recent studies have highlighted the potential of manipulating signal transduction systems as a means to chemically re-wire bacterial pathogens, thereby reducing selective pressure and avoiding the emergence of antibiotic resistance. This review begins by providing a brief introduction to characterized infection strategies and common virulence factors among APEC, NMEC, and UPEC and continues with a comprehensive overview of two-component signal transduction networks that have been shown to influence ExPEC pathogenesis.

  10. Efficient and stable photoelctrochemical water oxidation by ZnO photoanode coupled with Eu2O3 as novel oxygen evolution catalyst

    NASA Astrophysics Data System (ADS)

    Xie, Shilei; Wei, Wenjie; Huang, Senchuan; Li, Mingyang; Fang, Pingping; Lu, Xihong; Tong, Yexiang

    2015-11-01

    With the increasingly energy and environmental problems, photoelectrochemical (PEC) water splitting has recently attracted a great deal of attention. The slow oxygen evolution reaction (OER) involved in O-H bond breaking and attendant Odbnd O bond formation has restricted the efficiency of PEC water splitting. Herein, we demonstrate for the first time that the Eu2O3 can work as OER catalyst to significantly promote the performance of PEC water splitting. Because of its surface valance transition, the Eu2O3/ZnO shows an obvious water oxidation peak at 1.90 V vs. RHE, with a cathodic shift of around 200 mV to that of ZnO. The Eu2O3/ZnO can also yield a current density of 3.5 times larger than that of ZnO. Furthermore, similar enhancements can be also observed for the TiO2 and BiVO4, confirming the Eu2O3 is a general and efficient OER catalyst for improving the PEC performance. Such OER catalyst of Eu2O3 may bring new opportunities for the development of PEC cells with superior performance.

  11. Highly selective transformation of ammonia nitrogen to N2 based on a novel solar-driven photoelectrocatalytic-chlorine radical reactions system.

    PubMed

    Ji, Youzhi; Bai, Jing; Li, Jinhua; Luo, Tao; Qiao, Li; Zeng, Qingyi; Zhou, Baoxue

    2017-08-24

    A highly selective method for transforming ammonia nitrogen to N2 was proposed, based on a novel solar-driven photoelectrocatalytic-chlorine radical reactions (PEC-chlorine) system. The PEC-chlorine system was facilitated by a visible light response WO3 nanoplate array (NPA) electrode in an ammonia solution containing chloride ions (Cl(-)). Under illumination, photoholes from WO3 promote the oxidation of Cl(-) to chlorine radical (Cl). This radical can selectively transform ammonia nitrogen to N2 (79.9%) and NO3(-) (19.2%), similar to the breakpoint chlorination reaction. The ammonia nitrogen removal efficiency increased from 10.6% (PEC without Cl(-)) to 99.9% with the PEC-chlorine system within 90 min operation, which can be attributed to the cyclic reactions between Cl(-)/Cl and the reaction intermediates (NH2, NHCl, etc.) that expand the degradation reactions from the surface of the electrodes to the whole solution system. Moreover, Cl is the main radical species contributing to the transformation of ammonia nitrogen to N2, which is confirmed by the tBuOH capture experiment. Compared to conventional breakpoint chlorination, the PEC-chlorine system is a more economical and efficient means for ammonia nitrogen degradation because of the fast removal rate, no additional chlorine cost, and its use of clean energy (since it is solar-driven). Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. PERIOD ERROR ESTIMATION FOR THE KEPLER ECLIPSING BINARY CATALOG

    SciTech Connect

    Mighell, Kenneth J.; Plavchan, Peter

    2013-06-15

    The Kepler Eclipsing Binary Catalog (KEBC) describes 2165 eclipsing binaries identified in the 115 deg{sup 2} Kepler Field based on observations from Kepler quarters Q0, Q1, and Q2. The periods in the KEBC are given in units of days out to six decimal places but no period errors are provided. We present the PEC (Period Error Calculator) algorithm, which can be used to estimate the period errors of strictly periodic variables observed by the Kepler Mission. The PEC algorithm is based on propagation of error theory and assumes that observation of every light curve peak/minimum in a long time-series observation can be unambiguously identified. The PEC algorithm can be efficiently programmed using just a few lines of C computer language code. The PEC algorithm was used to develop a simple model that provides period error estimates for eclipsing binaries in the KEBC with periods less than 62.5 days: log {sigma}{sub P} Almost-Equal-To - 5.8908 + 1.4425(1 + log P), where P is the period of an eclipsing binary in the KEBC in units of days. KEBC systems with periods {>=}62.5 days have KEBC period errors of {approx}0.0144 days. Periods and period errors of seven eclipsing binary systems in the KEBC were measured using the NASA Exoplanet Archive Periodogram Service and compared to period errors estimated using the PEC algorithm.

  13. The association between antiphospholipid antibodies and pregnancy morbidity, stroke, myocardial infarction, and deep vein thrombosis: a critical review of the literature.

    PubMed

    Chighizola, C B; Andreoli, L; de Jesus, G Ramires; Banzato, A; Pons-Estel, G J; Erkan, D

    2015-08-01

    In a previous systematic literature search, we demonstrated that the frequencies of antiphospholipid antibodies (aPL) in general-population patients with pregnancy morbidity (PM), deep vein thrombosis (DVT), myocardial infarction (MI), and stroke (ST) are 6%, 10%, 11%, and 14%. To determine the association between aPL and clinical outcomes, we conducted a follow-up analysis of the 120 studies included in the original paper. Based on the analysis of 81 studies, a significant difference in the frequency of aPL criteria tests between patients and controls emerged considering all the outcomes together (10% versus 3%). In particular, a significant difference was reported for overall PM, pregnancy loss (PrL), late PrL, severe preeclampsia (PEC), ST, MI, and DVT. No difference emerged for early PrL, intrauterine growth restriction (IUGR), PEC, eclampsia (EC), and HELLP. A positive association was found in more than half of the studies for overall PrL, severe PEC, HELLP, ST, MI, and DVT and in less than half for early and late PrL, PEC, EC, and IUGR. The positive association between aPL and clinical outcomes included in the antiphospholipid syndrome classification criteria is not supported by every study, being particularly inconsistent for early PL, IUGR, PEC, EC, and HELLP.

  14. Final Project Report

    SciTech Connect

    Zhang, Jin; Zhao, Yiping

    2014-12-05

    In this entire project period from 2005-2014, we have made significant progress in developing novel nanostructures of metal oxides (MOs) for solar hydrogen generation based on photoelectrochemical (PEC). Materials investigated are focused on 1D and 0D MO nanostructures of TiO2, WO3, ZnO, and Fe2O3 in conjunction with quantum dot (QD) sensitization and chemical doping (N or H) to alter their electronic band structures for both visible light absorption and for facilitating interfacial charge transport. In addition, we have used plasmonic metal nanostructures to enhance the PEC performance by improving light absorption of QDs via enhanced scattering of the plamonic metal. Most importantly, we have discovered a multipronged strategy for improving PEC performance: using plasmonic metal nanostructure to enhance light absorption, QDs to improve charge transfer, and chemical doping to increase charge transport in metal oxides for PEC. The combination is critical for overall high efficiency of PEC. This strategy is developed and demonstrated for the first time to our best knowledge.

  15. A novel multi-amplification photoelectrochemical immunoassay based on copper(II) enhanced polythiophene sensitized graphitic carbon nitride nanosheet.

    PubMed

    Li, Rongxia; Liu, Yixin; Li, Xiaojian; Zhang, Sen; Wu, Dan; Zhang, Yong; Wei, Qin; Du, Bin

    2014-12-15

    A new sandwich photoelectrochemical (PEC) sensing strategy was proposed for the first time based on the increasing photocurrent of water-soluble polythiophene sensitized g-C3N4 nanosheet (PT-Cl/g-C3N4) in the presence of copper(II) (Cu(2+)), which was doped on the surface of titanium dioxide as labels for multi-amplification. Herein, the photoactive films of PT-Cl/g-C3N4 is employed as the photoactive antibody (Ab1) immobilization matrix for the subsequent sandwich-type antibody-antigen affinity interactions. Upon the presence of antigen (Ag), greatly enhanced photocurrent could be triggered in the PEC platform by the labels of second antibody (Ab2) of Cu(2+) doped titanium dioxide (Cu(2+)-TiO2). As a result of the multi-amplification in this Cu(2+)-TiO2 enhanced PT-Cl/g-C3N4-based PEC immunoassay, it possesses excellent analytical performance. The antigen could be detected from 0.01 pg mL(-1) to 100.0 ng mL(-1) with a detection limit of 5 fg mL(-1). This work opens up g-C3N4 nanosheet applied in PEC sensing. More importantly, the strategy of specific positive effect of Cu(2+) on the photocurrent of g-C3N4 opens an alternative horizon for PEC sensing.

  16. Environmental risk assessment of human pharmaceuticals in Denmark after normal therapeutic use.

    PubMed

    Stuer-Lauridsen, F; Birkved, M; Hansen, L P; Lützhøft, H C; Halling-Sørensen, B

    2000-04-01

    An environmental risk assessment is presented for the 25 most used pharmaceuticals in the primary health sector in Denmark. Predicted environmental concentrations (PECs) for the aquatic environment were calculated using conservative assumptions and all PECs exceeded 1 ng/l. Measured concentrations were in general within a factor of 2-5 of PECs and ranged from approximately 0.5 ng/l to 3 micrograms/l for nine of the pharmaceuticals reported in literature. The calculation of predicted no-effect concentration (PNEC) based on aquatic ecotoxicity data was possible for six of the pharmaceuticals. PEC/PNEC ratio exceeded one for ibuprofen, acetylsalicylic acid, and paracetamol. For estrogens the PEC/PNEC ratio approached one when non-standard test was used. The ratio was below one for estrogens (standard test), diazepam and digoxin. For the terrestrial compartment, toxicity data were not available, and no assessment was carried out. Comparisons of predicted concentrations of furosemide, ibuprofen, oxytetracycline and ciprofloxacin in sludge based on either preliminary experimental sludge-water partition coefficients (Kd), octanol-water coefficients (Kow) or acid-base constants (pKa) revealed large variations.

  17. Photoelectrochemical aptasensing of kanamycin using visible light-activated carbon nitride and graphene oxide nanocomposites.

    PubMed

    Li, Ruizhen; Liu, Yong; Cheng, Ling; Yang, Changzhu; Zhang, Jingdong

    2014-10-07

    Photoactive material and recognition element are two crucial factors which determine the sensitivity and selectivity of the photoelectrochemical (PEC) sensor. Herein we developed a novel PEC aptamer sensor for the specific detection of kanamycin using water-dispersible graphite-like carbon nitride (w-g-C3N4) as visible light-active material and aptamer as the biorecognition element. While a suitable amount of graphene oxide (GO) was doped in w-g-C3N4, the visible light photocurrent response was enhanced, which was beneficial to the construction of PEC sensor. On the other hand, the large specific surface area and π-conjugated structure of GO/w-g-C3N4 provided an excellent platform for immobilizing the kanamycin-binding DNA aptamer on the surface of the sensor via π-π stacking interaction. On such a sensor, the capture of kanamycin molecules by aptamer resulted in increased photocurrent. The PEC response of the sensor was found to be linearly proportional to the concentration of kanamycin in the range from 1 nM to 230 nM with a detection limit (3S/N) of 0.2 nM. Moreover, the proposed sensor displayed high selectivity, good reproducibility, and high stability, demonstrating the successful combination of GO/w-g-C3N4 with aptamer in fabricating high performance PEC sensors.

  18. Au@CdS Core–Shell Nanoparticles‐Modified ZnO Nanowires Photoanode for Efficient Photoelectrochemical Water Splitting

    PubMed Central

    Guo, Chun Xian; Xie, Jiale; Yang, Hongbin

    2015-01-01

    Hydrogen production from water splitting using solar energy based on photoelectrochemical (PEC) cells has attracted increasing attention because it leaves less of a carbon footprint and has economic superiority of solar and hydrogen energy. Oxide semiconductors such as ZnO possessing high stability against photocorrosion in hole scavenger systems have been widely used to build photoanodes of PEC cells but under visible light their conversion efficiencies with respect to incident‐photon‐to‐current conversion efficiency (IPCE) measured without external bias are still not satisfied. An innovative way is presented here to significantly improve the conversion efficiency of PEC cells by constructing a core–shell structure‐based photoanode comprising Au@CdS core–shell nanoparticles on ZnO nanowires (Au@CdS‐ZnO). The Au core offers strong electronic interactions with both CdS and ZnO resulting in a unique nanojunction to facilitate charge transfer. The Au@CdS‐ZnO PEC cell under 400 nm light irradiation without any applied bias provides an IPCE of 14.8%. Under AM1.5 light illumination with a bias of 0.4 V, the Au@CdS‐ZnO PEC cell produces H2 at a constant rate of 11.5 μmol h−1 as long as 10 h. This work provides a fundamental insight to improve the conversion efficiency for visible light in water splitting. PMID:27980921

  19. Oxygen-Free Condition Inhibited Biofilm Formation in Extraintestinal Pathogenic Escherichia coli Strain PPECC42 Through Preventing Curli Production.

    PubMed

    Meng, Xianrong; Zhang, Liyuan; Hou, Bo; Liu, Xueling; Li, Shaowen

    2016-08-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) is an important zoonotic and foodborne pathogen. Biofilms are specially structured communities for bacteria to survive in different hostile environments and can protect the bacteria from eradication by the host and external factors. In this study, we found that oxygen is definitely required for biofilm formation in ExPEC strain PPECC42. Aerobically growing ExPEC showed a bdar (brown, dry, and rough) morphotype, whereas anaerobically growing ExPEC showed a saw (smooth and white) morphotype. Under anaerobic condition, curli fimbriae did not accumulate and the expression levels of curli biosynthesis-related genes including csgB, csgD, and rpoS decreased significantly; in contrast, the expression level of h-ns, of which the encoding protein is a repressor for csgD transcription, increased significantly. Taken together, the results suggested that oxygen-free condition limited ExPEC strain PPECC42 biofilm formation mainly through preventing curli accumulation by affecting the transcriptional levels of curli biosynthesis-related genes.

  20. Effects of passing electric current on the elastic property of amorphous Cu{sub 50}Zr{sub 50} and Cu{sub 50}Ti{sub 50}

    SciTech Connect

    Takemoto, R.; Nagata, M.; Mizubayashi, H.

    1996-07-01

    For both amorphous Cu{sub 50}Zr{sub 50} and Cu{sub 50}Ti{sub 50}, the dynamic Young`s modulus M was found to increase under passing electric d.c.-current (PEC) with the current density i{sub d} below 5 {times} 10{sup 3} A/cm{sup 2}, suggesting that PEC induces internal stress. The i{sub d} dependence of M observed at low strain amplitude {epsilon}{sub t} was found to be identical to the {epsilon}{sub t} dependence of M without PEC after scaling between i{sub d} and {epsilon}{sub t}, giving Z* in the order of 10{sup 5}, where Z* is the apparent charge number measuring the electromigration force (EM-force) under PEC. The authors surmise that such a large Z* reflects the concentration of EM-force through the collective motion of many atoms, Z* = z*{xi}, for {xi} atoms with the charge number z* per atom. Application of this view to the observed effect of annealing on Z* gives {xi} as several hundreds in the as-quenched state. Based on the present results, the effects of PEC on the structural relaxation and crystallization processes reported are also discussed.

  1. Graphitic carbon nitride/BiOCl composites for sensitive photoelectrochemical detection of ciprofloxacin.

    PubMed

    Xu, Li; Li, Henan; Yan, Pengcheng; Xia, Jiexiang; Qiu, Jingxia; Xu, Qian; Zhang, Shanqing; Li, Huaming; Yuan, Shouqi

    2016-12-01

    Ciprofloxacin, as a second generation of fluoroquinolone antibiotics, has been proved to cause environmental harm and exhibits toxic effects on the wastewater and surface water even at low concentrations due to their continuous input and persistence. Despite tremendous efforts, developing ciprofloxacin detection method with accuracy and sensitivity at low-cost remains a great challenge. Herein, graphitic carbon nitride/BiOCl composite (g-CN/BiOCl) has been designed for a facile and sensitive photoelectrochemical (PEC) monitoring platform of ciprofloxacin at first time. BiOCl can be modified with the g-CN nanosheets which are obtained via solvothermal process at low-temperature conditions. The use of g-CN is shown to strongly enhance the PEC response of BiOCl due to the formation of heterojunctions. The photocurrent generated at the g-CN/BiOCl-modified ITO (with 13wt%g-CN content) is much higher and more stable than that of a BiOCl-modified ITO. Based on these findings, the g-CN/BiOCl-modified ITO was used to design a PEC assay for the antibiotic ciprofloxacin. Furthermore, the limit of detection of the ciprofloxacin PEC sensor has been significantly lowered to 0.2ngmL(-1). In addition, the PEC sensor can detect ciprofloxacin in the wide range of 0.5-1840ngmL(-1).

  2. Simplified human model and pedestrian simulation in the millimeter-wave region

    NASA Astrophysics Data System (ADS)

    Han, Junghwan; Kim, Seok; Lee, Tae-Yun; Ka, Min-Ho

    2016-02-01

    The 24 GHz and 77 GHz radar sensors have been studied as a strong candidate for advanced driver assistance systems(ADAS) because of their all-weather capability and accurate range and radial velocity measuring scheme. However, developing a reliable pedestrian recognition system hasmany obstacles due to the inaccurate and non-trivial radar responses at these high frequencies and the many combinations of clothes and accessories. To overcome these obstacles, many researchers used electromagnetic (EM) simulation to characterize the radar scattering response of a human. However, human simulation takes so long time because of the electrically huge size of a human in the millimeter-wave region. To reduce simulation time, some researchers assumed the skin of a human is the perfect electric conductor (PEC) and have simulated the PEC human model using physical optics (PO) algorithm without a specific explanation about how the human body could be modeled with PEC. In this study, the validity of the assumption that the surface of the human body is considered PEC in the EM simulation is verified, and the simulation result of the dry skin human model is compared with that of the PEC human model.

  3. Robust identification of metabolic control for microbial l-methionine production following an easy-to-use puristic approach.

    PubMed

    Teleki, A; Rahnert, M; Bungart, O; Gann, B; Ochrombel, I; Takors, R

    2017-05-01

    The identification of promising metabolic engineering targets is a key issue in metabolic control analysis (MCA). Conventional approaches make intensive use of model-based studies, such as exploiting post-pulse metabolic dynamics after proper perturbation of the microbial system. Here, we present an easy-to-use, purely data-driven approach, defining pool efflux capacities (PEC) for identifying reactions that exert the highest flux control in linear pathways. Comparisons with linlog-based MCA and data-driven substrate elasticities (DDSE) showed that similar key control steps were identified using PEC. Using the example of l-methionine production with recombinant Escherichia coli, PEC consistently and robustly identified main flux controls using perturbation data after a non-labeled (12)C-l-serine stimulus. Furthermore, the application of full-labeled (13)C-l-serine stimuli yielded additional insights into stimulus propagation to l-methionine. PEC analysis performed on the (13)C data set revealed the same targets as the (12)C data set. Notably, the typical drawback of metabolome analysis, namely, the omnipresent leakage of metabolites, was excluded using the (13)C PEC approach. Copyright © 2017 International Metabolic Engineering Society. Published by Elsevier Inc. All rights reserved.

  4. Antibiotics and iron-limiting conditions and their effect on the production and composition of outer membrane vesicles secreted from clinical isolates of extraintestinal pathogenic E. coli.

    PubMed

    Chan, Kin W; Shone, Clifford; Hesp, J Richard

    2017-01-01

    The focus of this study was to characterize the effect of clinically relevant stress-inducing conditions on the production and composition of proinflammatory outer membrane vesicles (OMVs) produced from ST131 extraintestinal pathogenic Escherichia coli (ExPEC) clinical isolates. A label-free method (relative normalized spectral index quantification, SINQ) was used to identify changes in the respective OMV proteomes following exposure of the ExPEC strains to antibiotics and low iron. Nanoparticle tracking analysis was used to quantify changes in abundance and size of OMVs produced by the gentamicin-resistant (GenR) and gentamicin-sensitive (GenS) ExPEC strains. Up to a 13.1-fold increase in abundance of particles were detected when the gentamicin-sensitive strain was exposed to a range of gentamicin concentrations. In contrast, no increase was observed for the gentamicin-resistant strain. Iron-limiting conditions had minimal effect on OMV production for either strain. Marked changes in the OMV proteome were observed for both strains including increases in Hsp100/Clp proteins, ATP-dependent ClpP protease, and regulatory proteins. These data provide information on changes in the composition of OMV particles derived from ExPEC strains generated in response to clinically relevant conditions. We show that the levels of the proinflammatory OMVs increase for gentamicin-sensitive ExPEC exposed to the antibiotic. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Coordinated Hospital-Home Fecal Microbiota Transplantation via Percutaneous Endoscopic Cecostomy for Recurrent Steroid-Dependent Ulcerative Colitis

    PubMed Central

    Ni, Xiaodong; Fan, Shengxian; Zhang, Yongliang; Wang, Zhiming; Ding, Lan; Li, Yousheng; Li, Jieshou

    2016-01-01

    Since its introduction as an alternative intestinal microbiota alteration approach, fecal microbiota transplantation (FMT) has been increasingly used as a treatment of choice for patients with ulcerative colitis (UC), but no reports exist regarding FMT via percutaneous endoscopic cecostomy (PEC). This report describes the case of a 24-year-old man with a 7-year history of recurrent, steroid-dependent UC. He received FMT via PEC once per day for 1 month in the hospital. After the remission of gastrointestinal symptoms, he was discharged from the hospital and continued FMT via PEC twice per week for 3 months at home. The frequency of stools decreased, and the characteristics of stools improved soon thereafter. Enteral nutrition was regained after 1 week, and an oral diet was begun 1 month later. Two months after the FMT end point, the patient resumed a normal diet, with formed soft stools once per day. The follow-up colonoscopy showed normal mucus membranes; then, the PEC set was removed. On the subsequent 12 months follow-up, the patient resumed orthobiosis without any gastrointestinal discomfort and returned to work. This case emphasizes that FMT via PEC can not only induce remission but also shorten the duration of hospitalization and reduce the medical costs; therefore, this approach should be considered an alternative option for patients with UC. PMID:27282271

  6. Fracture mode, microstructure and temperature-dependent elastic moduli for thermoelectric composites of PbTe-PbS with SiC nanoparticle additions

    NASA Astrophysics Data System (ADS)

    Ni, Jennifer E.; Case, Eldon D.; Schmidt, Robert D.; Wu, Chun-I.; Hogan, Timothy P.; Trejo, Rosa M.; Lara-Curzio, Edgar; Kanatzidis, Mercouri G.

    2013-12-01

    Twenty-six (Pb0.95Sn0.05Te)0.92(PbS)0.08-0.055% PbI2-SiC nanoparticle (SiCnp) composite thermoelectric specimens were either hot pressed or pulsed electric current sintered (PECS). Bloating (a thermally induced increase in porosity, P, for as-densified specimens) was observed during annealing at temperatures >603 K for hot-pressed specimens and PECS-processed specimens from wet milled powders, but in contrast seven out of seven specimens densified by PECS from dry milled powders showed no observable bloating following annealing at temperatures up to 936 K. In this study, bloating in the specimens was accessed via thermal annealing induced changes in (i) porosity measured by scanning electron microscopy on fractured specimen surfaces, (ii) specimen volume and (iii) elastic moduli. The moduli were measured by resonant ultrasound spectroscopy. SiCnp additions (1-3.5 vol.%) changed the fracture mode from intergranular to transgranular, inhibited grain growth, and limited bloating in the wet milled PECS specimens. Inhibition of bloating likely occurs due to cleaning of contamination from powder particle surfaces via PECS processing which has been reported previously in the literature.

  7. Identification of protective and broadly conserved vaccine antigens from the genome of extraintestinal pathogenic Escherichia coli.

    PubMed

    Moriel, Danilo Gomes; Bertoldi, Isabella; Spagnuolo, Angela; Marchi, Sara; Rosini, Roberto; Nesta, Barbara; Pastorello, Ilaria; Corea, Vanja A Mariani; Torricelli, Giulia; Cartocci, Elena; Savino, Silvana; Scarselli, Maria; Dobrindt, Ulrich; Hacker, Jörg; Tettelin, Hervé; Tallon, Luke J; Sullivan, Steven; Wieler, Lothar H; Ewers, Christa; Pickard, Derek; Dougan, Gordon; Fontana, Maria Rita; Rappuoli, Rino; Pizza, Mariagrazia; Serino, Laura

    2010-05-18

    Extraintestinal pathogenic Escherichia coli (ExPEC) are a common cause of disease in both mammals and birds. A vaccine to prevent such infections would be desirable given the increasing antibiotic resistance of these bacteria. We have determined the genome sequence of ExPEC IHE3034 (ST95) isolated from a case of neonatal meningitis and compared this to available genome sequences of other ExPEC strains and a few nonpathogenic E. coli. We found 19 genomic islands present in the genome of IHE3034, which are absent in the nonpathogenic E. coli isolates. By using subtractive reverse vaccinology we identified 230 antigens present in ExPEC but absent (or present with low similarity) in nonpathogenic strains. Nine antigens were protective in a mouse challenge model. Some of them were also present in other pathogenic non-ExPEC strains, suggesting that a broadly protective E. coli vaccine may be possible. The gene encoding the most protective antigen was detected in most of the E. coli isolates, highly conserved in sequence and found to be exported by a type II secretion system which seems to be nonfunctional in nonpathogenic strains.

  8. Towards efficient solar-to-hydrogen conversion: Fundamentals and recent progress in copper-based chalcogenide photocathodes

    NASA Astrophysics Data System (ADS)

    Chen, Yubin; Feng, Xiaoyang; Liu, Maochang; Su, Jinzhan; Shen, Shaohua

    2016-09-01

    Photoelectrochemical (PEC) water splitting for hydrogen generation has been considered as a promising route to convert and store solar energy into chemical fuels. In terms of its large-scale application, seeking semiconductor photoelectrodes with high efficiency and good stability should be essential. Although an enormous number of materials have been explored for solar water splitting in the last several decades, challenges still remain for the practical application. P-type copper-based chalcogenides, such as Cu(In, Ga)Se2 and Cu2ZnSnS4, have shown impressive performance in photovoltaics due to narrow bandgaps, high absorption coefficients, and good carrier transport properties. The obtained high efficiencies in photovoltaics have promoted the utilization of these materials into the field of PEC water splitting. A comprehensive review on copper-based chalcogenides for solar-to-hydrogen conversion would help advance the research in this expanding area. This review will cover the physicochemical properties of copper-based chalco-genides, developments of various photocathodes, strategies to enhance the PEC activity and stability, introductions of tandem PEC cells, and finally, prospects on their potential for the practical solar-to-hydrogen conversion. We believe this review article can provide some insights of fundamentals and applications of copper-based chalco-genide thin films for PEC water splitting.

  9. An Overview of Two-Component Signal Transduction Systems Implicated in Extra-Intestinal Pathogenic E. coli Infections

    PubMed Central

    Breland, Erin J.; Eberly, Allison R.; Hadjifrangiskou, Maria

    2017-01-01

    Extra-intestinal pathogenic E. coli (ExPEC) infections are common in mammals and birds. The predominant ExPEC types are avian pathogenic E. coli (APEC), neonatal meningitis causing E. coli/meningitis associated E. coli (NMEC/MAEC), and uropathogenic E. coli (UPEC). Many reviews have described current knowledge on ExPEC infection strategies and virulence factors, especially for UPEC. However, surprisingly little has been reported on the regulatory modules that have been identified as critical in ExPEC pathogenesis. Two-component systems (TCSs) comprise the predominant method by which bacteria respond to changing environments and play significant roles in modulating bacterial fitness in diverse niches. Recent studies have highlighted the potential of manipulating signal transduction systems as a means to chemically re-wire bacterial pathogens, thereby reducing selective pressure and avoiding the emergence of antibiotic resistance. This review begins by providing a brief introduction to characterized infection strategies and common virulence factors among APEC, NMEC, and UPEC and continues with a comprehensive overview of two-component signal transduction networks that have been shown to influence ExPEC pathogenesis. PMID:28536675

  10. Recent Advances in Photoelectrochemical Applications of Silicon Materials for Solar-to-Chemicals Conversion.

    PubMed

    Shi, Jingying; Zhang, Dou Dou; Zi, Wei; Wang, Peng Peng; Liu, Sheng Zhong

    2017-10-04

    Photoelectrochemical (PEC) technology for the conversion of solar energy to chemicals requires cost-effective photoelectrodes to efficiently and stably drive anodic and/or cathodic half-reactions to complete the overall reactions for storing solar energy in chemical bonds. The shared properties among semiconducting photoelectrodes and photovoltaic (PV) materials are light absorption and charge separation and charge transfer. Earth-abundant silicon materials have been widely applied in the PV industry, demonstrating their efficiency as alternative photoabsorbers for photoelectrodes. Many efforts have been made to fabricate silicon photoelectrodes with enhanced performance, and significant progress has been achieved in recent years. In this review, we summarize the recent developments of crystalline and thin-film silicon-based photoelectrodes (including amorphous, microcrystalline and nanocrystalline silicon) immersed in aqueous solution for PEC hydrogen production from water splitting, as well as applications in PEC CO2 reduction and PEC regeneration of discharged species in redox flow batteries. We believe that silicon is an ideal material for the cost-effective production of solar chemicals through PEC methods. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effects of exposure to dietary chromium on tissue mineral contents in rats fed diets with fiber.

    PubMed

    Prescha, Anna; Krzysik, Monika; Zabłocka-Słowińska, Katarzyna; Grajeta, Halina

    2014-06-01

    This study evaluated the effects of diets with fiber (cellulose and/or pectin) supplemented with chromium(III) on homeostasis of selected minerals in femurs, thigh muscles, livers, and kidneys of rats. For 6 weeks, male rats were fed experimental diets: a fiber-free diet (FF), a diet containing 5% cellulose (CEL), 5% pectin (PEC), or 2.5% cellulose and 2.5% pectin (CEL+PEC). These diets had 2.53 or 0.164 mg Cr/kg diet. The tissue levels of Ca, Mg, Zn, Fe, and Cr were determined by using atomic absorption spectrometry. Supplementing diets with Cr resulted in significantly higher Cr levels in the femurs of rats fed the CEL diet and significantly higher Cr and Fe levels in the rats fed the CEL+PEC diet compared to the rats fed FF diet. Muscle Ca content was significantly lower in the rats fed the CEL+PEC+Cr diet compared to the rats fed FF+Cr diet. The rats consuming the PEC+Cr diet had the highest liver Cr content. The highest kidney Zn content was observed in the rats fed diets containing Cr and one type of fiber. These results indicate that diets containing chromium at elevated dose and fiber have a significant effect on the mineral balance in rat tissues.

  12. Production of staphylococcal enterotoxin F and pyrogenic exotoxin C by Staphylococcus aureus isolates from toxic shock syndrome-associated sources.

    PubMed Central

    Bonventre, P F; Weckbach, L; Staneck, J; Schlievert, P M; Thompson, M

    1983-01-01

    A total of 136 isolates of Staphylococcus aureus were tested for production of staphylococcal enterotoxin F (SEF) and pyrogenic exotoxin C (PEC), both of which have been identified as reliable indicators of toxic shock syndrome (TSS)-associated strains. SEF and PEC production by isolates from TSS-associated and other sources was tested independently in two laboratories, after which the two sets of data were compared. A 100% concordance between SEF and PEC production was obtained. The TSS toxin candidates were produced by 30 of 136 isolates, and in all instances SEF and PEC were made concurrently by the same strains; in no case was one toxin made and not the other. In the five groups of S. aureus tested, toxins were detected as follows: 23 of 25 (92%) acute TSS isolates, 2 of 48 (4.2%) genital non-TSS isolates, 2 of 16 (12.5%) recovered TSS isolates, 1 of 23 (4.3%) clinical nongenital isolates, and 2 of 24 (8.3%) enterotoxigenic food outbreak isolates. Comparison of purified SEF and purified PEC by immunological and biochemical criteria by immunodiffusion, isoelectric focusing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blot analysis show that the toxins are immunologically identical and strongly suggest that the two nominal TSS toxins are in fact a single protein. Images PMID:6189784

  13. Growth of β-Ga2O3 and GaN nanowires on GaN for photoelectrochemical hydrogen generation.

    PubMed

    Hwang, Jih-Shang; Liu, Tai-Yan; Chattopadhyay, Surjit; Hsu, Geng-Ming; Basilio, Antonio M; Chen, Han-Wei; Hsu, Yu-Kuei; Tu, Wen-Hsun; Lin, Yan-Gu; Chen, Kuei-Hsien; Li, Chien-Cheng; Wang, Sheng-Bo; Chen, Hsin-Yi; Chen, Li-Chyong

    2013-02-08

    Enhanced photoelectrochemical (PEC) performances of Ga(2)O(3) and GaN nanowires (NWs) grown in situ from GaN were demonstrated. The PEC conversion efficiencies of Ga(2)O(3) and GaN NWs have been shown to be 0.906% and 1.09% respectively, in contrast to their 0.581% GaN thin film counterpart under similar experimental conditions. A low crystallinity buffer layer between the grown NWs and the substrate was found to be detrimental to the PEC performance, but the layer can be avoided at suitable growth conditions. A band bending at the surface of the GaN NWs generates an electric field that drives the photogenerated electrons and holes away from each other, preventing recombination, and was found to be responsible for the enhanced PEC performance. The enhanced PEC efficiency of the Ga(2)O(3) NWs is aided by the optical absorption through a defect band centered 3.3 eV above the valence band of Ga(2)O(3). These findings are believed to have opened up possibilities for enabling visible absorption, either by tailoring ion doping into wide bandgap Ga(2)O(3) NWs, or by incorporation of indium to form InGaN NWs.

  14. Electrochemical synthesis of nanoporous tungsten carbide and its application as electrocatalysts for photoelectrochemical cells.

    PubMed

    Kang, Jin Soo; Kim, Jin; Lee, Myeong Jae; Son, Yoon Jun; Jeong, Juwon; Chung, Dong Young; Lim, Ahyoun; Choe, Heeman; Park, Hyun S; Sung, Yung-Eun

    2017-03-16

    Photoelectrochemical (PEC) cells are promising tools for renewable and sustainable solar energy conversion. Currently, their inadequate performance and high cost of the noble metals used in the electrocatalytic counter electrode have postponed the practical use of PEC cells. In this study, we report the electrochemical synthesis of nanoporous tungsten carbide and its application as a reduction catalyst in PEC cells, namely, dye-sensitized solar cells (DSCs) and PEC water splitting cells, for the first time. The method employed in this study involves the anodization of tungsten foil followed by post heat treatment in a CO atmosphere to produce highly crystalline tungsten carbide film with an interconnected nanostructure. This exhibited high catalytic activity for the reduction of cobalt bipyridine species, which represent state-of-the-art redox couples for DSCs. The performance of tungsten carbide even surpassed that of Pt, and a substantial increase (∼25%) in energy conversion efficiency was achieved when Pt was substituted by tungsten carbide film as the counter electrode. In addition, tungsten carbide displayed decent activity as a catalyst for the hydrogen evolution reaction, suggesting the high feasibility for its utilization as a cathode material for PEC water splitting cells, which was also verified in a two-electrode water photoelectrolyzer.

  15. Construction of Er(3+) :YAlO3 /RGO/TiO2 Hybrid Electrode with Enhanced Photoelectrocatalytic Performance in Methylene Blue Degradation Under Visible Light.

    PubMed

    Zhou, Xian; Zhang, Jun; Ma, Yue; Cheng, Hanqing; Fu, Shaozhu; Zhou, Dandan; Dong, Shuangshi

    2017-04-09

    Much attention has been paid on doping TiO2 to narrow its band gap to promote the absorption of visible light and restrain the recombination of electron-hole pairs to improve its efficiency in photoelectrocatalysis (PEC) under visible-light irradiation. However, the oxidation potential energy of photo-induced holes for the modified catalysts by visible-light excitation is lower than that without modification by UV excitation. In this work, we synthesized a co-coupled TiO2 electrode (denoted ERT) with the Er(3+) :YAlO3 and reduced graphene oxide (RGO), achieving the synergetic effect of visible-light-to-UV up-conversion and response and great electron transfer ability. The effects of external bias voltage, electrolyte concentration and pH on the PEC activity were studied with the methylene blue (MB) as the target pollutant. The results indicated that PEC by the ERT electrode showed the highest MB removal compared with those by the electrodes coupled with RGO or Er(3+) :YAlO3 alone. In addition, the kinetic rate constant of the PEC process using the ERT electrode was higher than the sum of those of the photocatalytic and electrocatalytic processes. The optimal conditions for PEC by the ERT electrode were an external bias voltage of 1.0 V, 0.1 mol L(-1) Na2 SO4 and pH = 10. © 2017 The American Society of Photobiology.

  16. Magnetic loading of TiO2/SiO2/Fe3O4 nanoparticles on electrode surface for photoelectrocatalytic degradation of diclofenac.

    PubMed

    Hu, Xinyue; Yang, Juan; Zhang, Jingdong

    2011-11-30

    A novel magnetic nanomaterials-loaded electrode developed for photoelectrocatalytic (PEC) treatment of pollutants was described. Prior to electrode fabrication, magnetic TiO(2)/SiO(2)/Fe(3)O(4) (TSF) nanoparticles were synthesized and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and FT-IR measurements. The nanoparticles were dispersed in ethanol and then immobilized on a graphite electrode surface with aid of magnet to obtain a TSF-loaded electrode with high photoelectrochemical activity. The performance of the TSF-loaded electrode was tested by comparing the PEC degradation of methylene blue in the presence and absence of magnet. The magnetically attached TSF electrode showed higher PEC degradation efficiency with desirable stability. Such a TSF-loaded electrode was applied to PEC degradation of diclofenac. After 45 min PEC treatment, 95.3% of diclofenac was degraded on the magnetically attached TSF electrode. Copyright © 2011 Elsevier B.V. All rights reserved.

  17. The crucial role of bile acids in the entry of porcine enteric calicivirus.

    PubMed

    Shivanna, Vinay; Kim, Yunjeong; Chang, Kyeong-Ok

    2014-05-01

    Replication of porcine enteric calicivirus (PEC) in LLC-PK cells is dependent on the presence of bile acids in the medium. However, the mechanism of bile acid-dependent PEC replication is unknown. Understanding of bile acid-mediated PEC replication may provide insight into cultivating related human noroviruses, currently uncultivable, which are the major cause of viral gastroenteritis outbreaks in humans. Our results demonstrated that while uptake of PEC into the endosomes does not require bile acids, the presence of bile acids is critical for viral escape from the endosomes into cell cytoplasm to initiate viral replication. We also demonstrated that bile acid transporters including the sodium-taurocholate co-transporting polypeptide and the apical sodium-dependent bile acid transporter are important in exerting the effects of bile acids in PEC replication in cells. In summary, our results suggest that bile acids play a critical role in virus entry for successful replication. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Compound effects of aging and experimental FSGS on glomerular epithelial cells

    PubMed Central

    Kutz, J. Nathan; Sweetwyne, Mariya T.; Pippin, Jeffrey W.; Shankland, Stuart J.

    2017-01-01

    Advanced age portends a poorer prognosis in FSGS. To understand the impact of age on glomerular podocytes and parietal epithelial cells (PECs), experimental FSGS was induced in 3m-old mice (20-year old human age) and 27m-old mice (78-year old human age) by abruptly depleting podocytes with a cytopathic anti-podocyte antibody. Despite similar binding of the disease-inducing antibody, podocyte density was lower in aged FSGS mice compared to young FSGS mice. Activated PEC density was higher in aged versus young FSGS mice, as was the percentage of total activated PECs. Additionally, the percentage of glomeruli containing PECs with evidence of phosphorylated ERK and EMT was higher in aged FSGS mice. Extracellular matrix, measured by collagen IV and silver staining, was higher in aged FSGS mice along Bowman's capsule. However, collagen IV accumulation in the glomerular tufts alone and in glomeruli with both tuft and Bowman's capsule accumulation were similar in young FSGS and aged FSGS mice. Thus, the major difference in collagen IV staining in FSGS was along Bowman's capsule in aged mice. The significant differences in podocytes, PECs and extracellular matrixaccumulation between young mice and old mice with FSGS might explain the differences in outcomes in FSGS based on age. PMID:28222042

  19. Genome-wide Screen of Pseudomonas aeruginosa in Saccharomyces cerevisiae Identifies New Virulence Factors.

    PubMed

    Zrieq, Rafat; Sana, Thibault G; Vergin, Sandra; Garvis, Steve; Volfson, Irina; Bleves, Sophie; Voulhoux, Romé; Hegemann, Johannes H

    2015-01-01

    Pseudomonas aeruginosa is a human opportunistic pathogen that causes mortality in cystic fibrosis and immunocompromised patients. While many virulence factors of this pathogen have already been identified, several remain to be discovered. In this respect we set an unprecedented genome-wide screen of a P. aeruginosa expression library based on a yeast growth phenotype. Fifty-one candidates were selected in athree-round screening process. The robustness of the screen was validated by the selection of three well known secreted proteins including one demonstrated virulence factor, the protease LepA. Further in silico sorting of the 51 candidates highlighted three potential new Pseudomonas effector candidates (Pec). By testing the cytotoxicity of wild type P. aeruginosa vs. pec mutants toward macrophages and the virulence in the Caenorhabditis elegans model, we demonstrated that the three selected Pecs are novel virulence factors of P. aeruginosa. Additional cellular localization experiments in the host revealed specific localization for Pec1 and Pec2 that could inform about their respective functions.

  20. Carbon-shell-decorated p-semiconductor PbMoO4 nanocrystals for efficient and stable photocathode of photoelectrochemical water reduction

    NASA Astrophysics Data System (ADS)

    Wang, Ligang; Tang, Hanqin; Tian, Yang

    2016-07-01

    Photoelectrochemical (PEC) water splitting using semiconductors is a promising method for the future scalable production of renewable hydrogen fuels. The critical issues in PEC water splitting include the development of the photoelectrode materials with high efficiency and long-term stability, especially for p-type semiconductor photocathodes. Herein, we report the use of citric acid (CA) pyrolysis to prepare carbon-shell-decorated PbMoO4 (C@PbMoO4) nanocrystals via a simple solvothermal method. Different carbon shell thicknesses below 10 nm were generated by varying the amount of CA in the precursor solution. In contrast, without using CA, bare PbMoO4 nanocrystals were obtained. The PEC experiments showed that 2-nm carbon shell could preferably improve the water splitting performance of PbMoO4: the photocurrent density of 2-nm C@PbMoO4 is nearly 2-fold high as that of bare PbMoO4 at 0 V versus reversible hydrogen electrode (RHE). The surface charge transfer efficiency of 2-nm C@PbMoO4 in the PEC process was tested to increase from 83% to 90.4%, the charge separation efficiency enhanced 56%, and the PEC stability also greatly increased compared to those of the bare PbMoO4 nanocrystals. This strategy could be applied to other p-type semiconducting photocathodes for low-cost solar-fuel-generation devices.

  1. Testing of NASA LaRC Materials under MISSE 6 and MISSE 7 Missions

    NASA Technical Reports Server (NTRS)

    Prasad, Narasimha S.

    2009-01-01

    The objective of the Materials International Space Station Experiment (MISSE) is to study the performance of novel materials when subjected to the synergistic effects of the harsh space environment for several months. MISSE missions provide an opportunity for developing space qualifiable materials. Two lasers and a few optical components from NASA Langley Research Center (LaRC) were included in the MISSE 6 mission for long term exposure. MISSE 6 items were characterized and packed inside a ruggedized Passive Experiment Container (PEC) that resembles a suitcase. The PEC was tested for survivability due to launch conditions. MISSE 6 was transported to the international Space Station (ISS) via STS 123 on March 11. 2008. The astronauts successfully attached the PEC to external handrails of the ISS and opened the PEC for long term exposure to the space environment. The current plan is to bring the MISSE 6 PEC back to the Earth via STS 128 mission scheduled for launch in August 2009. Currently, preparations for launching the MISSE 7 mission are progressing. Laser and lidar components assembled on a flight-worthy platform are included from NASA LaRC. MISSE 7 launch is scheduled to be launched on STS 129 mission. This paper will briefly review recent efforts on MISSE 6 and MISSE 7 missions at NASA Langley Research Center (LaRC).

  2. A novel, biodegradable and reversible polyelectrolyte platform for topical-colonic delivery of pentosan polysulphate.

    PubMed

    Shah, Hardik K; Conkie, Jim A; Tait, Robert C; Johnson, James R; Wilson, Clive G

    2011-02-14

    The goal of the present work was to develop a swellable hydrogel colonic delivery system, which would maximise the availability of the therapeutic agent at a site of inflammation, especially where the water is scarce. A novel method was developed to manufacture a biodegradable and reversible polyelectrolyte complex (PEC) containing chitosan and poly acrylic-acid (PAA). The PEC was analysed using FTIR and DSC, which confirmed the formation of non-permanent swollen gel-network at an alkaline pH. Pentosan polysulphate (PPS) was incorporated in a PEC and an activated partial thromboplastin time assay was developed to measure the release of PPS from PEC. In vitro studies suggested that the release of PPS was dependent on the initial drug loading and the composition of the PEC. The gel strength of the swollen network, determined using a texture analyser, was dependent on polymer composition and the amount of PPS incorporated. Bacterial enzymes were collected from the rat caecum and colon for the digestion studies and characterised for glucosidase activity, glucuronidase activity and protein content. The digestion of the reversible polyelectrolyte complexes was measured using a dinitro salicylic acid assay and an increased release of drug was also confirmed in the presence of bacterial enzymes.

  3. Femtomole level photoelectrochemical aptasensing for mercury ions using quercetin-copper(II) complex as the DNA intercalator.

    PubMed

    Li, Hongbo; Xue, Yan; Wang, Wei

    2014-04-15

    An ultrasensitive and selective photoelectrochemical (PEC) aptasensor for mercury ions was first fabricated based on perylene-3, 4, 9, 10-tetracarboxylic acid/graphene oxide (PTCA/GO) heterojunction using quercetin-copper(II) complex intercalated into the poly(dT)-poly(dA) duplexes. Both the PTCA/GO heterojunction and the quercetin-copper(II) complex are in favor of the sensitivity for the fabricated PEC aptasensor due to band alignment and strong reduction capability, respectively. And they efficiently promote the separation of photoexcited carriers and enhance the photocurrent. The formation of thymine-Hg(2+)-thymine coordination chemistry resulted in the dehybridization of poly(dT)-poly(dA) duplexes and then the intercalator quercetin-copper(II) complex broke away from the surface of the PEC aptasensor. As the concentration of mercury ions increased, the photocurrent gradually decreased. The electrode response for mercury ions detection was in the linear range from 0.01 pmol L(-1) to 1.00 pmol L(-1) with the detection limit of 3.33 fmol L(-1). The label-free PEC aptasensor has excellent performances with ultrasensitivity and good selectivity besides the advantage of economic and facile fabrication. The strategy of quercetin-copper(II) complex as a novel DNA intercalator paves a new way to improve the performances for PEC sensors. © 2013 Published by Elsevier B.V.

  4. Microfabricated photocrosslinkable polyelectrolyte-complex of chitosan and methacrylated gellan gum

    PubMed Central

    Coutinho, Daniela F.; Sant, Shilpa; Shakiba, Mojdeh; Wang, Ben; Gomes, Manuela E.; Neves, Nuno M.; Reis, Rui L.

    2012-01-01

    Chitosan (CHT) based polyelectrolyte complexes (PECs) have been receiving great attention for tissue engineering approaches. These hydrogels are held together by ionic forces and can be disrupted by changes in physiological conditions. In this study, we present a new class of CHT-based PEC hydrogels amenable to stabilization by chemical crosslinking. The photocrosslinkable anionic methacrylated gellan gum (MeGG) was complexed with cationic CHT and exposed to light, forming a PEC hydrogel. The chemical characterization of the photocrosslinkable PEC hydrogel by Fourier transform infrared spectroscopy (FTIR) revealed absorption peaks specific to the raw polymers. A significantly higher swelling ratio was observed for the PEC hydrogel with higher CHT content. The molecular interactions between both polysaccharides were evaluated chemically and microscopically, indicating the diffusion of CHT to the interior of the hydrogel. We hypothesized that the addition of MeGG to CHT solution first leads to a membrane formation around MeGG. Then, migration of CHT inside the MeGG hydrogel occurs to balance the electrostatic charges. The photocrosslinkable feature of MeGG further allowed the formation of cell-laden microscale hydrogel units with different shapes and sizes. Overall, this system is potentially useful for a variety of applications including the replication of microscale features of tissues for modular tissue engineering. PMID:23293429

  5. Genome-wide Screen of Pseudomonas aeruginosa in Saccharomyces cerevisiae Identifies New Virulence Factors

    PubMed Central

    Zrieq, Rafat; Sana, Thibault G.; Vergin, Sandra; Garvis, Steve; Volfson, Irina; Bleves, Sophie; Voulhoux, Romé; Hegemann, Johannes H.

    2015-01-01

    Pseudomonas aeruginosa is a human opportunistic pathogen that causes mortality in cystic fibrosis and immunocompromised patients. While many virulence factors of this pathogen have already been identified, several remain to be discovered. In this respect we set an unprecedented genome-wide screen of a P. aeruginosa expression library based on a yeast growth phenotype. Fifty-one candidates were selected in athree-round screening process. The robustness of the screen was validated by the selection of three well known secreted proteins including one demonstrated virulence factor, the protease LepA. Further in silico sorting of the 51 candidates highlighted three potential new Pseudomonas effector candidates (Pec). By testing the cytotoxicity of wild type P. aeruginosa vs. pec mutants toward macrophages and the virulence in the Caenorhabditis elegans model, we demonstrated that the three selected Pecs are novel virulence factors of P. aeruginosa. Additional cellular localization experiments in the host revealed specific localization for Pec1 and Pec2 that could inform about their respective functions. PMID:26636043

  6. Evolution of the iss gene in Escherichia coli.

    PubMed

    Johnson, Timothy J; Wannemuehler, Yvonne M; Nolan, Lisa K

    2008-04-01

    The increased serum survival gene iss has long been recognized for its role in extraintestinal pathogenic Escherichia coli (ExPEC) virulence. iss has been identified as a distinguishing trait of avian ExPEC but not of human ExPEC. This gene has been localized to large virulence plasmids and shares strong similarities with the bor gene from bacteriophage lambda. Here, we demonstrate that three alleles of iss occur among E. coli isolates that appear to have evolved from a common lambda bor precursor. In addition to the occurrence of iss on the ColV/BM virulence plasmids, at least two iss alleles occur within the E. coli chromosome. One of these alleles (designated type 3) was found to occur in the genomes of all currently sequenced ExPEC strains on a similar prophage element that also harbors the Sit iron and manganese transport system. When the prevalence of the three iss types was examined among 487 E. coli isolates, the iss type 3 gene was found to occur at a high frequency among ExPEC isolates, irrespective of the host source. The plasmid-borne iss allele (designated type 1) was highly prevalent among avian pathogenic E. coli and neonatal meningitis-associated E. coli isolates but not among uropathogenic E. coli isolates. This study demonstrates the evolution of iss in E. coli and provides an additional tool for discriminating among E. coli pathotypes through the differentiation of the three iss allele types and bor.

  7. Polyelectrolyte complexes of poly[(2-dimethylamino) ethyl methacrylate]/chondroitin sulfate obtained at different pHs: I. Preparation, characterization, cytotoxicity and controlled release of chondroitin sulfate.

    PubMed

    Bonkovoski, Letícia C; Martins, Alessandro F; Bellettini, Ismael C; Garcia, Francielle P; Nakamura, Celso V; Rubira, Adley F; Muniz, Edvani C

    2014-12-30

    For the first time, polyelectrolyte complex based on poly[(2-dimethylamino) ethyl methacrylate] (PDMAEMA) and chondroitin sulfate (CS) was prepared. The properties of novel material and precursors were investigated by WAXS, FTIR, TGA, SEM and DLS analysis. The PDMAEMA/CS PECs presented hydrophilic-hydrophobic transition at pHs 6.0, 7.0 and 8.0 whereas the non-complexed PDMAEMA showed such a transition at pH 8.0 and not at pHs 6.0 and 7.0. Studies of CS release from PECs at pHs 6 and 8 confirmed that the samples possess the potential to release the CS in alkaline and not in acidic conditions. Since PECs are thermo-responsive due to the reduction of LCST caused by the increase in pH, the release of CS was dependent on temperature and pH factors. Cytotoxicity assays using healthy VERO cells showed that the complexation between CS and PDMAEMA increased the PECs' biocompatibility related to PDMAEMA. However, the biocompatibility depends on the amount of CS present in the PECs.

  8. TiO2-BiVO4 Heterostructure to Enhance Photoelectrochemical Efficiency for Sensitive Aptasensing.

    PubMed

    Liu, Pei Pei; Liu, Xiaoqiang; Huo, Xiao He; Tang, Yunfei; Xu, Jun; Ju, Huangxian

    2017-08-16

    This work designed a nanocomposite to enhance the photoelectrochemical (PEC) efficiency by depositing BiVO4 nanoparticles on TiO2 nanospheres with a solvothermal method. The TiO2-BiVO4 heterostructure was characterized with various spectroscopic and microscopic techniques and was employed as a nanostructured support to cross-link DNA aptamer for constructing a visible-light driven PEC aptasensor. The TiO2 nanospheres provided a biocompatible microenvironment, and the high surface area of the heterostructure enhanced the loading of aptamer molecules. The small energy gap of BiVO4 improved the PEC property of the nanocomposite compared with the pure TiO2 under visible-light irradiation. The advantages of the nanocomposite along with the high loading of recognition molecules greatly improved the sensitivity of the aptasensor. Using 17β-estradiol as an analyst model, the proposed PEC biosensor showed excellent analytical performance with high sensitivity, low detection limit of 0.022 pM, and high selectivity in a detectable concentration range of 0.1-250 pM, indicating the promising application of the designed TiO2-BiVO4 heterostructure in PEC biosensing.

  9. A Member of the PLEIOTROPIC DRUG RESISTANCE Family of ATP Binding Cassette Transporters Is Required for the Formation of a Functional Cuticle in Arabidopsis[W

    PubMed Central

    Bessire, Michael; Borel, Sandra; Fabre, Guillaume; Carraça, Luis; Efremova, Nadia; Yephremov, Alexander; Cao, Yan; Jetter, Reinhard; Jacquat, Anne-Claude; Métraux, Jean-Pierre; Nawrath, Christiane

    2011-01-01

    Although the multilayered structure of the plant cuticle was discovered many years ago, the molecular basis of its formation and the functional relevance of the layers are not understood. Here, we present the permeable cuticle1 (pec1) mutant of Arabidopsis thaliana, which displays features associated with a highly permeable cuticle in several organs. In pec1 flowers, typical cutin monomers, such as ω-hydroxylated fatty acids and 10,16-dihydroxypalmitate, are reduced to 40% of wild-type levels and are accompanied by the appearance of lipidic inclusions within the epidermal cell. The cuticular layer of the cell wall, rather than the cuticle proper, is structurally altered in pec1 petals. Therefore, a significant role for the formation of the diffusion barrier in petals can be attributed to this layer. Thus, pec1 defines a new class of mutants. The phenotypes of the pec1 mutant are caused by the knockout of ATP BINDING CASSETTEG32 (ABCG32), an ABC transporter from the PLEIOTROPIC DRUG RESISTANCE family that is localized at the plasma membrane of epidermal cells in a polar manner toward the surface of the organs. Our results suggest that ABCG32 is involved in the formation of the cuticular layer of the cell wall, most likely by exporting particular cutin precursors from the epidermal cell. PMID:21628525

  10. Recognition unit-free and self-cleaning photoelectrochemical sensing platform on TiO2 nanotube photonic crystals for sensitive and selective detection of dopamine release from mouse brain.

    PubMed

    Xin, Yanmei; Li, Zhenzhen; Wu, Wenlong; Fu, Baihe; Wu, Hongjun; Zhang, Zhonghai

    2017-01-15

    For implementing sensitive and selective detection of biological molecules, the biosensors are been designed more and more complicated. The exploration of detection platform in a simple way without loss their sensitivity and selectivity is always a big challenge. Herein, a prototype of recognition biomolecule unit-free photoelectrochemical (PEC) sensing platform with self-cleaning activity is proposed with TiO2 nanotube photonic crystal (TiO2 NTPCs) materials as photoelectrode, and dopamine (DA) molecule as both sensitizer and target analyte. The unique adsorption between DA and TiO2 NTPCs induces the formation of charge transfer complex, which not only expends the optical absorption of TiO2 into visible light region, thus significantly boosts the PEC performance under illumination of visible light, but also implements the selective detection of DA on TiO2 photoelectrode. This simple but efficient PEC analysis platform presents a low detection limit of 0.15nm for detection of DA, which allows to realize the sensitive and selective determination of DA release from the mouse brain for its practical application after coupled with a microdialysis probe. The DA functionalized TiO2 NTPCs PEC sensing platform opens up a new PEC detection model, without using extra-biomolecule auxiliary, just with target molecule naturally adsorbed on the electrode for sensitive and selective detection, and paves a new avenue for biosensors design with minimalism idea.

  11. Light harvesting proteins for solar fuel generation in bioengineered photoelectrochemical cells.

    PubMed

    Ihssen, Julian; Braun, Artur; Faccio, Greta; Gajda-Schrantz, Krisztina; Thöny-Meyer, Linda

    2014-01-01

    The sun is the primary energy source of our planet and potentially can supply all societies with more than just their basic energy needs. Demand of electric energy can be satisfied with photovoltaics, however the global demand for fuels is even higher. The direct way to produce the solar fuel hydrogen is by water splitting in photoelectrochemical (PEC) cells, an artificial mimic of photosynthesis. There is currently strong resurging interest for solar fuels produced by PEC cells, but some fundamental technological problems need to be solved to make PEC water splitting an economic, competitive alternative. One of the problems is to provide a low cost, high performing water oxidizing and oxygen evolving photoanode in an environmentally benign setting. Hematite, α-Fe2O3, satisfies many requirements for a good PEC photoanode, but its efficiency is insufficient in its pristine form. A promising strategy for enhancing photocurrent density takes advantage of photosynthetic proteins. In this paper we give an overview of how electrode surfaces in general and hematite photoanodes in particular can be functionalized with light harvesting proteins. Specifically, we demonstrate how low-cost biomaterials such as cyanobacterial phycocyanin and enzymatically produced melanin increase the overall performance of virtually no-cost metal oxide photoanodes in a PEC system. The implementation of biomaterials changes the overall nature of the photoanode assembly in a way that aggressive alkaline electrolytes such as concentrated KOH are not required anymore. Rather, a more environmentally benign and pH neutral electrolyte can be used.

  12. Fabricating photoelectrochemical aptasensor for selectively monitoring microcystin-LR residues in fish based on visible light-responsive BiOBr nanoflakes/N-doped graphene photoelectrode.

    PubMed

    Du, Xiaojiao; Jiang, Ding; Dai, Liming; Zhou, Lei; Hao, Nan; Qian, Jing; Qiu, Baijing; Wang, Kun

    2016-07-15

    The presence of microcystins in fish has been augmenting the risk of toxicity to animal and human health. Herein, a selective and sensitive method for detecting microcystin-LR (MC-LR) in fish samples by integrating the photoelectrochemical (PEC) technique and the specific recognition ability of aptamer was developed. Specifically, as an efficient PEC transducer, the BiOBr nanoflakes/N-doped graphene p-n heterojunction electrode was utilized as the aptamer immobilization platform via the π-π stacking interaction, which would be a biosensor enabling the convenient and exquisite PEC analysis. Subsequently, the PEC response of constructed aptasensor was specific binding to MC-LR. Other isoforms did not interfere with the detection process, and thus, it could be applied for the highly selective determination of MC-LR level. Under the optimized condition, the PEC signal versus the logarithm of the MC-LR concentration was in good linear relationship ranging from 0.1pM to 100nM with detection limit about 0.03pM. The constructed method was employed to analyze fish samples collected from the local supermarket. The overall analytical recovery of MC-LR in the fish matrices ranged from 97.8 to 101.6%, with relative standard deviation (RSD) of 2.52-5.14%, implying it would have great potential in farm product analysis.

  13. A member of the PLEIOTROPIC DRUG RESISTANCE family of ATP binding cassette transporters is required for the formation of a functional cuticle in Arabidopsis.

    PubMed

    Bessire, Michael; Borel, Sandra; Fabre, Guillaume; Carraça, Luis; Efremova, Nadia; Yephremov, Alexander; Cao, Yan; Jetter, Reinhard; Jacquat, Anne-Claude; Métraux, Jean-Pierre; Nawrath, Christiane

    2011-05-01

    Although the multilayered structure of the plant cuticle was discovered many years ago, the molecular basis of its formation and the functional relevance of the layers are not understood. Here, we present the permeable cuticle1 (pec1) mutant of Arabidopsis thaliana, which displays features associated with a highly permeable cuticle in several organs. In pec1 flowers, typical cutin monomers, such as ω-hydroxylated fatty acids and 10,16-dihydroxypalmitate, are reduced to 40% of wild-type levels and are accompanied by the appearance of lipidic inclusions within the epidermal cell. The cuticular layer of the cell wall, rather than the cuticle proper, is structurally altered in pec1 petals. Therefore, a significant role for the formation of the diffusion barrier in petals can be attributed to this layer. Thus, pec1 defines a new class of mutants. The phenotypes of the pec1 mutant are caused by the knockout of ATP BINDING CASSETTEG32 (ABCG32), an ABC transporter from the PLEIOTROPIC DRUG RESISTANCE family that is localized at the plasma membrane of epidermal cells in a polar manner toward the surface of the organs. Our results suggest that ABCG32 is involved in the formation of the cuticular layer of the cell wall, most likely by exporting particular cutin precursors from the epidermal cell.

  14. Engineering Polyelectrolyte Capsules with Independently Controlled Size and Shape.

    PubMed

    Zan, Xingjie; Garapaty, Anusha; Champion, Julie A

    2015-07-14

    Polyelectrolyte capsules (PECs) are a promising delivery system that has the ability to carry a large payload of a variety of cargoes. Controlling PEC properties is critical to understanding and tuning their cellular uptake efficiency, kinetics, and mechanism as well as their biodistribution in the body. The lack of a method to independently engineer PEC size, shape, and chemistry impedes both basic understanding of how physicochemical parameters affect PEC behavior in drug delivery and other applications, and the ability to optimize parameters for best function. Here, we report the successful fabrication of PECs having constant surface chemistry with independently controlled size and shape by combining soft organic templates created by the particle stretching method and a modified layer-by-layer (LBL) deposition process. Changing the template dispersion solution during LBL deposition from water to ethanol allowed us to overcome previous issues with organic templates, such as aggregation and template removal. These results will contribute not only to the basic study of the role of capsule shape and size on its function but also to the optimization of capsule properties for drug or imaging carriers, sensors, reactors, and other applications.

  15. Genomic Microbial Epidemiology Is Needed to Comprehend the Global Problem of Antibiotic Resistance and to Improve Pathogen Diagnosis

    PubMed Central

    Wyrsch, Ethan R.; Roy Chowdhury, Piklu; Chapman, Toni A.; Charles, Ian G.; Hammond, Jeffrey M.; Djordjevic, Steven P.

    2016-01-01

    Contamination of waste effluent from hospitals and intensive food animal production with antimicrobial residues is an immense global problem. Antimicrobial residues exert selection pressures that influence the acquisition of antimicrobial resistance and virulence genes in diverse microbial populations. Despite these concerns there is only a limited understanding of how antimicrobial residues contribute to the global problem of antimicrobial resistance. Furthermore, rapid detection of emerging bacterial pathogens and strains with resistance to more than one antibiotic class remains a challenge. A comprehensive, sequence-based genomic epidemiological surveillance model that captures essential microbial metadata is needed, both to improve surveillance for antimicrobial resistance and to monitor pathogen evolution. Escherichia coli is an important pathogen causing both intestinal [intestinal pathogenic E. coli (IPEC)] and extraintestinal [extraintestinal pathogenic E. coli (ExPEC)] disease in humans and food animals. ExPEC are the most frequently isolated Gram negative pathogen affecting human health, linked to food production practices and are often resistant to multiple antibiotics. Cattle are a known reservoir of IPEC but they are not recognized as a source of ExPEC that impact human or animal health. In contrast, poultry are a recognized source of multiple antibiotic resistant ExPEC, while swine have received comparatively less attention in this regard. Here, we review what is known about ExPEC in swine and how pig production contributes to the problem of antibiotic resistance. PMID:27379026

  16. Role of Au(III) coordination by polymer in "green" synthesis of gold nanoparticles using chitosan derivatives.

    PubMed

    Pestov, Alexander; Nazirov, Alexander; Privar, Yuliya; Modin, Evgeny; Bratskaya, Svetlana

    2016-10-01

    Here we report "green" synthesis of gold nanoparticles in solutions of heterocyclic chitosan derivatives (N-(4-imidazolyl)methylchitosan (IMC), N-2-(2-pyridyl)ethylchitosan (2-PEC), and N-2-(4-pyridyl)ethylchitosan (4-PEC)) and show how efficiency of Au(III) binding to polymer influences the Au(III) reduction rate and the size of the gold nanoparticles formed using only the reducing power of these chitosan derivatives. Rheology measurements and (1)H NMR spectroscopy data have confirmed that cleavage of glycosidic bond is a common mechanism of reducing species generation in solutions of chitosan and its N-heterocyclic derivatives. However, the emerging additional reducing species in 2-PEC and 4-PEC solutions due to vinylpyridine elimination promotes Au(III) reduction and gold nanoparticles growth despite lower efficiency of glycosidic bond cleavage in pyridyl derivatives. The decrease of the average size of gold nanoparticles in the row chitosan>2-PEC>IMC supported assumption that the increase of ligand nucleophilicity and stability of Au(III)-polymer complex results in formation of smaller nanoparticles.

  17. Identification of protective and broadly conserved vaccine antigens from the genome of extraintestinal pathogenic Escherichia coli

    PubMed Central

    Rappuoli, Rino; Serino, Laura

    2010-01-01

    Extraintestinal pathogenic Escherichia coli (ExPEC) are a common cause of disease in both mammals and birds. A vaccine to prevent such infections would be desirable given the increasing antibiotic resistance of these bacteria. We have determined the genome sequence of ExPEC IHE3034 (ST95) isolated from a case of neonatal meningitis and compared this to available genome sequences of other ExPEC strains and a few nonpathogenic E. coli. We found 19 genomic islands present in the genome of IHE3034, which are absent in the nonpathogenic E. coli isolates. By using subtractive reverse vaccinology we identified 230 antigens present in ExPEC but absent (or present with low similarity) in nonpathogenic strains. Nine antigens were protective in a mouse challenge model. Some of them were also present in other pathogenic non-ExPEC strains, suggesting that a broadly protective E. coli vaccine may be possible. The gene encoding the most protective antigen was detected in most of the E. coli isolates, highly conserved in sequence and found to be exported by a type II secretion system which seems to be nonfunctional in nonpathogenic strains. PMID:20439758

  18. Fracture mode, microstructure and temperature-dependent elastic moduli for thermoelectric composites of PbTe PbS with SiC nanoparticle additions

    SciTech Connect

    Ni, Jennifer E; Case, Eldon D; Hogan, Timophy P.; Trejo, Rosa M; Lara-Curzio, Edgar; Kanatzidis, Mercouri G.

    2013-01-01

    Twenty-six (Pb0.95Sn0.05Te)0.92(PbS)0.08 0.055% PbI2 SiC nanoparticle (SiCnp) composite thermoelectric specimens were either hot pressed or pulsed electric current sintered (PECS). Bloating (a thermally induced increase in porosity, P, for as-densified specimens) was observed during annealing at temperatures >603 K for hot-pressed specimens and PECS-processed specimens from wet milled powders, but in contrast seven out of seven specimens densified by PECS from dry milled powders showed no observable bloating following annealing at temperatures up to 936 K. In this study, bloating in the specimens was accessed via thermal annealing induced changes in (i) porosity measured by scanning electron microscopy on fractured specimen surfaces, (ii) specimen volume and (iii) elastic moduli. The moduli were measured by resonant ultrasound spectroscopy. SiCnp additions (1 3.5 vol.%) changed the fracture mode from intergranular to transgranular, inhibited grain growth, and limited bloating in the wet milled PECS specimens. Inhibition of bloating likely occurs due to cleaning of contamination from powder particle surfaces via PECS processing which has been reported previously in the literature.

  19. Pathogenesis of Focal Segmental Glomerulosclerosis

    PubMed Central

    Lim, Beom Jin; Yang, Jae Won; Do, Woo Sung; Fogo, Agnes B.

    2016-01-01

    Focal segmental glomerulosclerosis (FSGS) is characterized by focal and segmental obliteration of glomerular capillary tufts with increased matrix. FSGS is classified as collapsing, tip, cellular, perihilar and not otherwise specified variants according to the location and character of the sclerotic lesion. Primary or idiopathic FSGS is considered to be related to podocyte injury, and the pathogenesis of podocyte injury has been actively investigated. Several circulating factors affecting podocyte permeability barrier have been proposed, but not proven to cause FSGS. FSGS may also be caused by genetic alterations. These genes are mainly those regulating slit diaphragm structure, actin cytoskeleton of podocytes, and foot process structure. The mode of inheritance and age of onset are different according to the gene involved. Recently, the role of parietal epithelial cells (PECs) has been highlighted. Podocytes and PECs have common mesenchymal progenitors, therefore, PECs could be a source of podocyte repopulation after podocyte injury. Activated PECs migrate along adhesion to the glomerular tuft and may also contribute to the progression of sclerosis. Markers of activated PECs, including CD44, could be used to distinguish FSGS from minimal change disease. The pathogenesis of FSGS is very complex; however, understanding basic mechanisms of podocyte injury is important not only for basic research, but also for daily diagnostic pathology practice. PMID:27744657

  20. Application of Model Based Parameter Estimation for RCS Frequency Response Calculations Using Method of Moments

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.

    1998-01-01

    An implementation of the Model Based Parameter Estimation (MBPE) technique is presented for obtaining the frequency response of the Radar Cross Section (RCS) of arbitrarily shaped, three-dimensional perfect electric conductor (PEC) bodies. An Electric Field Integral Equation (EFTE) is solved using the Method of Moments (MoM) to compute the RCS. The electric current is expanded in a rational function and the coefficients of the rational function are obtained using the frequency derivatives of the EFIE. Using the rational function, the electric current on the PEC body is obtained over a frequency band. Using the electric current at different frequencies, RCS of the PEC body is obtained over a wide frequency band. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth. Good agreement between MBPE and the exact solution over the bandwidth is observed.

  1. Zero photoelastic and water durable ZnO–SnO–P{sub 2}O{sub 5}–B{sub 2}O{sub 3} glasses

    SciTech Connect

    Saitoh, Akira; Nakata, Kohei; Yamamoto, Naoki; Takebe, Hiromichi; Tricot, Grégory; Chen, Yuanyuan

    2015-04-01

    We report properties of zero birefringent xZnO–(67–x)SnO–(33–y)P{sub 2}O{sub 5}–y B{sub 2}O{sub 3} glasses, within 18.5 ≤ x ≤ 22 and y = 0, 3, and 10 mol. %. These compositions of boro-phosphate glasses provide both zero photoelastic constant (PEC) and improved water durability. x = 19 and y = 3 compositions show minimum PEC of −0.002 × 10{sup −12} Pa{sup −1}, which can contribute to candidate material for fiber current sensor devise without lead. The structures of zero photoelastic glasses were investigated by Raman scattering and nuclear magnetic resonance spectroscopies. Compositions of zero PEC glasses are explained by the empirical model proposed by Zwanziger et al. [Chem. Mater. 19, 286-290 (2007)].

  2. Isolation and characterization of nicotiflorin obtained by enzymatic hydrolysis of two precursors in tea seed extract.

    PubMed

    Lee, Hyang-Bok; Kim, Eun-Ki; Park, Sang-Jae; Bang, Sang-Gu; Kim, Tae Gil; Chung, Dae-Won

    2010-04-28

    Two flavonol triglycosides, camelliaside A (CamA) and camelliaside B (CamB), of tea seed extract (TSE) were subjected to enzymatic hydrolysis. Among five kinds of glycosidases investigated, beta-galactosidase (Gal) induced selective hydrolysis of CamA. On the other hand, pectinase (Pec) and cellulase (Cel) induced hydrolysis of CamB. For Gal and Pec, only kaempferol diglycoside (nicotiflorin, NF) was produced; on the other hand, significant amounts of kaempferol monoglycoside (astragalin, AS) and kaempferol (KR) were also detected for Cel. The combination of the use of Gal and Pec in the enzymatic hydrolysis of TSE afforded NF with high specificity. Crude NF with 22% purity was recovered from the enzymatic reaction mixture by extraction with organic solvent, and pure NF with >95% purity was obtained by crystallized in water. The chemical structure of NF was confirmed by (1)H and (13)C NMR analyses.

  3. Hematite/Si nanowire dual-absorber system for photoelectrochemical water splitting at low applied potentials.

    PubMed

    Mayer, Matthew T; Du, Chun; Wang, Dunwei

    2012-08-01

    Hematite (α-Fe(2)O(3)) was grown on vertically aligned Si nanowires (NWs) using atomic layer deposition to form a dual-absorber system. Si NWs absorb photons that are transparent to hematite (600 nm < λ < 1100 nm) and convert the energy into additional photovoltage to assist photoelectrochemical (PEC) water splitting by hematite. Compared with hematite-only photoelectrodes, those with Si NWs exhibited a photocurrent turn-on potential as low as 0.6 V vs RHE. This result represents one of the lowest turn-on potentials observed for hematite-based PEC water splitting systems. It addresses a critical challenge of using hematite for PEC water splitting, namely, the fact that the band-edge positions are too positive for high-efficiency water splitting.

  4. Structural basis of transcriptional pausing in bacteria.

    PubMed

    Weixlbaumer, Albert; Leon, Katherine; Landick, Robert; Darst, Seth A

    2013-01-31

    Transcriptional pausing by multisubunit RNA polymerases (RNAPs) is a key mechanism for regulating gene expression in both prokaryotes and eukaryotes and is a prerequisite for transcription termination. Pausing and termination states are thought to arise through a common, elemental pause state that is inhibitory for nucleotide addition. We report three crystal structures of Thermus RNAP elemental paused elongation complexes (ePECs). The structures reveal the same relaxed, open-clamp RNAP conformation in the ePEC that may arise by failure to re-establish DNA contacts during translocation. A kinked bridge-helix sterically blocks the RNAP active site, explaining how this conformation inhibits RNAP catalytic activity. Our results provide a framework for understanding how RNA hairpin formation stabilizes the paused state and how the ePEC intermediate facilitates termination. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Mapping Photoelectrochemical Current Distribution at Nanoscale Dimensions on Morphologically Controlled BiVO4.

    PubMed

    Chakthranont, Pongkarn; Seitz, Linsey C; Jaramillo, Thomas F

    2015-09-17

    We develop a method that can be used to qualitatively map photocurrent on photoelectrode surfaces, and show its utility for morphologically controlled W-doped BiVO4. The method is based on the deliberate photoinduced sintering of Au NPs, a photon-driven process that indicates oxidation with nanoscale-resolution. This strategy allows us to identify the active regions on W-doped BiVO4 photoelectrodes, and we observe a strong dependence of photoactivity on the electrode morphology, controlled by varying the relative humidity during the sol-gel fabrication process. We find that photoelectrode morphologies that exhibit the most evenly distributed Au sintering are those that yield the highest photoelectrochemical (PEC) activity. Understanding the correlation between electrode morphology and PEC activity is essential for designing structured semiconductors for PEC water splitting.

  6. The global morphology of the plasmaspheric electron content during Northern winter 2009 based on GPS/COSMIC observation and GSM TIP model results

    NASA Astrophysics Data System (ADS)

    Klimenko, M. V.; Klimenko, V. V.; Zakharenkova, I. E.; Cherniak, Iu. V.

    2015-04-01

    We studied the contribution of the global plasmaspheric and ionospheric electron content (PEC and IEC) into total electron content (TEC). The experimental PEC was estimated by comparison of GPS TEC observations and FORMOSAT-3/COSMIC radio occultation IEC measurements. Results are retrieved for the winter solstice (January and December 2009) conditions. Global maps of COSMIC-derived IEC, PEC and GPS TEC were compared with Global Self-consistent Model of the Thermosphere, Ionosphere and Protonosphere (GSM TIP) results. In addition, we used GSM TIP model results in order to estimate the contribution of plasmaspheric electron content into TEC value at the different altitudinal regions. The advantages and problems of the outer ionospheric/plasmaspheric parameters (O+/H+ transition height, TEC and electron density at height above F2 layer peak) representation by the IRI (International Reference Ionosphere) model are discussed.

  7. Influence of pH on the quantum-size-controlled photoelectrochemical etching of epitaxial InGaN quantum dots

    DOE PAGES

    Xiao, Xiaoyin; Lu, Ping; Fischer, Arthur J.; ...

    2015-11-18

    Illumination by a narrow-band laser has been shown to enable photoelectrochemical (PEC) etching of InGaN thin films into quantum dots with sizes controlled by the laser wavelength. Here, we investigate and elucidate the influence of solution pH on such quantum-size-controlled PEC etch process. We find that although a pH above 5 is often used for PEC etching of GaN-based materials, oxides (In2O3 and/or Ga2O3) form which interfere with quantum dot formation. Furthermore, at pH below 3, however, oxide-free QDs with self-terminated sizes can be successfully realized.

  8. Influence of pH on the quantum-size-controlled photoelectrochemical etching of epitaxial InGaN quantum dots

    SciTech Connect

    Xiao, Xiaoyin; Lu, Ping; Fischer, Arthur J.; Coltrin, Michael E.; Wang, George T.; Koleske, Daniel D.; Tsao, Jeffrey Y.

    2015-11-18

    Illumination by a narrow-band laser has been shown to enable photoelectrochemical (PEC) etching of InGaN thin films into quantum dots with sizes controlled by the laser wavelength. Here, we investigate and elucidate the influence of solution pH on such quantum-size-controlled PEC etch process. We find that although a pH above 5 is often used for PEC etching of GaN-based materials, oxides (In2O3 and/or Ga2O3) form which interfere with quantum dot formation. Furthermore, at pH below 3, however, oxide-free QDs with self-terminated sizes can be successfully realized.

  9. Design and specification of a centralized manufacturing data management and scheduling system

    NASA Technical Reports Server (NTRS)

    Farrington, Phillip A.

    1993-01-01

    As was revealed in a previous study, the Materials and Processes Laboratory's Productivity Enhancement Complex (PEC) has a number of automated production areas/cells that are not effectively integrated, limiting the ability of users to readily share data. The recent decision to utilize the PEC for the fabrication of flight hardware has focused new attention on the problem and brought to light the need for an integrated data management and scheduling system. This report addresses this need by developing preliminary designs specifications for a centralized manufacturing data management and scheduling system for managing flight hardware fabrication in the PEC. This prototype system will be developed under the auspices of the Integrated Engineering Environment (IEE) Oversight team and the IEE Committee. At their recommendation the system specifications were based on the fabrication requirements of the AXAF-S Optical Bench.

  10. Plasmon enhanced photoelectrochemical sensing of mercury (II) ions in human serum based on Au@Ag nanorods modified TiO₂ nanosheets film.

    PubMed

    Zhang, Yong; Shoaib, Anwer; Li, Jiaojiao; Ji, Muwei; Liu, Jiajia; Xu, Meng; Tong, Bin; Zhang, Jiatao; Wei, Qin

    2016-05-15

    Taking advantages of the monodisperse TiO2 nanosheets (NSs) with high active crystal face exposure and the tunable localized surface plasmon resonance (LSPR) properties of Au@Ag nanorods (NRs), this study demonstrated that TiO2 NSs film with trace amount of Au@Ag NRs modification possess a strong enhancement of photocurrent response, which was remarkably inhibited with the addition of mercury (II) ions (Hg(2+)). Based on the selective decrease of photocurrent with the addition of Hg(2+), a simple photoelectrochemical (PEC) sensor has been assembled. The PEC sensor exhibits wide linear range (0.01-10nM), low detection limit (2.5 pM), satisfying selectivity, reproducibility and acceptable stability for Hg(2+) detection. The feasibility of this method for practical application in human serum has been evaluated and the result was satisfactory. This PEC sensing method would provide a potential application for Hg(2+) detection in clinical diagnosis.

  11. Photoelectrocatalytic degradation of triclosan on TiO2 nanotube arrays and toxicity change.

    PubMed

    Liu, Haijin; Cao, Xianglin; Liu, Guoguang; Wang, Yingling; Zhang, Nan; Li, Tong; Tough, Robert

    2013-09-01

    Triclosan, one of the most widely used disinfectants, has been found to be toxic to animals and human beings. In this paper, triclosan was degraded on TiO2 nanotube arrays, using a photoelectrocatalytic (PEC) process under UV illumination, with Na2SO4 as the supporting electrolyte. The effect of bias potential was investigated and the results showed that 0V was the most appropriate potential for the degradation of triclosan. In 30min, 78.7% of triclosan had degraded during the PEC process. Intermediate analysis showed that 2,7-dichlorodibenzodioxin (DCDD) had formed during the degradation. The toxicity change during the PEC process was investigated using a luminescent bacteria test, with the results demonstrating that the toxicity of the reaction liquid decreased at the beginning and subsequently increased to a stable level. The indications were that some intermediates such as 2,7-dichlorodibenzodioxin was more toxic and stable than triclosan in the solution.

  12. Ceramide Formation Mediated by Acid Sphingomyelinase Facilitates Endosomal Escape of Caliciviruses

    PubMed Central

    Shivanna, Vinay; Kim, Yunjeong; Chang, Kyeong-Ok

    2015-01-01

    Our recent results demonstrated that bile acids facilitate virus escape from the endosomes into the cytoplasm for successful replication of porcine enteric calicivirus (PEC). We report a novel finding that bile acids can be substituted by cold treatment for endosomal escape and virus replication. This endosomal escape by cold treatment or bile acids is associated with ceramide formation by acid sphingomyelinase (ASM). ASM catalyzes hydrolysis of sphingomyelin into ceramide, which is known to destabilize lipid bilayer. Treatment of LLC-PK cells with bile acids or cold led to ceramide formation, and small molecule antagonists or siRNA of ASM blocked ceramide formation in the endosomes and significantly reduced PEC replication. Inhibition of ASM resulted in the retention of PEC, feline calicivirus or murine norovirus in the endosomes in correlation with reduced viral replication. These results suggest the importance of viral escape from the endosomes for the replication of various caliciviruses. PMID:25985440

  13. Enteroaggregative Escherichia coli with uropathogenic characteristics are present in feces of diarrheic and healthy children.

    PubMed

    Nunes, Kamila O; Santos, Adriana C P; Bando, Silvia Y; Silva, Rosa M; Gomes, Tânia A T; Elias, Waldir P

    2017-11-30

    Enteroaggregative Escherichia coli (EAEC) has been recently associated with urinary tract infections (UTI). Since EAEC are found in feces of both diarrheic and asymptomatic individuals, their presence in the intestine may be a source of UTI. In this study, we detected in feces of diarrheic and healthy children a subset of EAEC strains with genetic markers of extraintestinal pathogenic E. coli (ExPEC). MLST grouped these EAEC with ExPEC markers in three main clusters along with prototypes strains of EAEC, uropathogenic E. coli and UTI-causing EAEC. Interestingly, the latter cluster was composed by EAEC with ExPEC markers belonging to phylogroup A and closely related to the uropathogenic EAEC O78:H10 strain. Such attributes suggest that these strains have uropathogenic abilities. Therefore, intestinal carriers of these strains are potentially in risk to develop UTIs. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. Enhanced Photovoltaic Properties of Potassium-Adsorbed Titania Nanotubes

    SciTech Connect

    Richter, C.; Jaye, C; Fischer, D; Lewis, L; Willey, R; Menon, L

    2009-01-01

    It is demonstrated that vertically-aligned titania nanotube planar arrays fabricated by electrochemical anodization using standard potassium-containing electrolytes invariably contain a significant amount of surface-adsorbed potassium ions, hitherto undetected, that affect the titania photoelectrochemical or PEC performance. Synchrotron-based near edge X-ray absorption fine structure (NEXAFS) spectroscopy reveals the strong ionic nature of surface potassium-titania bonds that alters the PEC performance over that of pure titania nanotubes through reduction of the external electrical bias needed to produce hydrogen at maximum efficiency. This result implies that the external electrical energy input required per liter of solar hydrogen produced with potassium-adsorbed titania nanotubes may be reduced. Tailoring the potassium content may thus be an alternative means to fine-tune the photoelectrochemical response of TiO2 nanotube-based PEC electrodes.

  15. Phenotypic microarrays suggest Escherichia coli ST131 is not a metabolically distinct lineage of extra-intestinal pathogenic E. coli.

    PubMed

    Alqasim, Abdulaziz; Emes, Richard; Clark, Gemma; Newcombe, Jane; La Ragione, Roberto; McNally, Alan

    2014-01-01

    Extraintestinal pathogenic E. coli (ExPEC) are the major aetiological agent of urinary tract infections (UTIs) in humans. The emergence of the CTX-M producing clone E. coli ST131 represents a major challenge to public health worldwide. A recent study on the metabolic potential of E. coli isolates demonstrated an association between the E. coli ST131 clone and enhanced utilisation of a panel of metabolic substrates. The studies presented here investigated the metabolic potential of ST131 and other major ExPEC ST isolates using 120 API test reagents and found that ST131 isolates demonstrated a lower metabolic activity for 5 of 120 biochemical tests in comparison to non-ST131 ExPEC isolates. Furthermore, comparative phenotypic microarray analysis showed a lack of specific metabolic profile for ST131 isolates countering the suggestion that these bacteria are metabolically fitter and therefore more successful human pathogens.

  16. Aquatic environmental assessment of the top 25 English prescription pharmaceuticals.

    PubMed

    Jones, O A H; Voulvoulis, N; Lester, J N

    2002-12-01

    An environmental assessment is presented for the 25 most used pharmaceuticals in the National Health Service (NHS) in England in 2000. Predicted environmental concentrations (PECs) for the aquatic environment were calculated using conservative assumptions and all PECs exceeded 1 ng 1 (-1). The calculation of predicted no-effect concentration (PNEC) based on aquatic toxicity data from the literature was possible for eleven of the pharmaceuticals. PNECs were predicted with ECOSAR for 12 of the remaining 14 but no data was available for two of the compounds. The PEC/ PNEC ratio exceeded one for Paracetamol, Amoxycillin, Oxytetracycline and Mefenamic acid. Comparisons of the predicted concentrations of the compounds in sewage sludge based on either calculated sludge-water coefficients (Kd), octanol water coefficients (K(ow)), acid base constants (pKa) or environmental modelling revealed large variations. No toxicity data was available for the terrestrial environment and no assessment was made.

  17. Assembling Supramolecular Dye-Sensitized Photoelectrochemical Cells for Water Splitting.

    PubMed

    Ding, Xin; Gao, Yan; Ye, Lu; Zhang, Linlin; Sun, Licheng

    2015-12-07

    The method used to assemble dye-sensitized photoelectrochemical (DS-PEC) devices plays a vital role in determining its photoactivity and stability. We report a simple and effective method to assemble supramolecular DS-PECs introducing PMMA as support material and a catalyst modified with long carbon chains as photoanodes. The long carbon chains in combination with PMMA allow to better immobilize the catalyst. DS-PECs obtained by this simple method have display excellent photoactivities and stabilities. A photocurrent density of 1.1 mA cm(-2) and a maximum IPCE of 9.5 % have been obtained with a 0.2 V vs NHE external bias. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Induced dipole in vanadium-doped zinc oxide nanosheets and its effects on photoelectrochemical water splitting.

    PubMed

    Lee, Song Mi; Shin, Sung-Ho; Nah, Junghyo; Lee, Min Hyung

    2017-09-27

    Appropriate control of energy band bending at the interface between semiconductors and electrolytes are closely related to performance of photoelectrochemical (PEC) water splitting. Dipoles formed near the surface of semiconductors induces energy band bending at the interface. Energy band bending control has been demonstrated by employing charged molecules and piezoelectric materials. However, chemical and piezoelectric approaches have demerit of chemical instability and inducement of instantaneous dipole, respectively. To overcome these problems, we adopted the ferroelectric material for PEC water splitting, where spontaneous dipoles in the material can be oriented by applying external electric field. In this work, we hydrothermally synthesized vanadium (V)-doped ferroelectric ZnO nanosheets and employed to systematically investigate the dipole effect on performance of V-doped ZnO PEC for water oxidation. Consequently, positively polarized V-doped ZnO photoanode exhibits 125% enhanced water splitting efficiency compared to negatively polarized ones due to favorable band bending for carrier transport from semiconductor to water.

  19. SUPRAMOLECULAR SYSTEMS BEHAVIOR AT THE AIR-WATER INTERFACE. MOLECULAR DYNAMIC SIMULATION STUDY

    SciTech Connect

    Sandoval, C.; Saavedra, M.; Gargallo, L.; Radic, D.

    2008-08-28

    Atomistic molecular dynamics simulation (MDS) was development to investigate the structural and dynamic properties of a monolayer of supramolecular systems. The simulations were performed at room temperature, on inclusion complexes (ICs) of {alpha}-cyclodextrin (CD) with poly(ethylene-oxide)(PEO), poly({epsilon}-caprolactone)(PEC) and poly(tetrahydrofuran)(PTHF). The simulations were carried out for a surface area of 30A ring . The trajectories of the MDS show that the system more stable was IC-PEC, being the less stable IC-PEO. The disordered monolayer for the systems was proved by the orientation correlation function and the radial distribution function between the polar groups of ICs and the water molecules. We found that the system IC-PEC was more stable that the systems IC-PTHF and IC-PEO.

  20. Low-toxic Ag2S quantum dots for photoelectrochemical detection glucose and cancer cells.

    PubMed

    Zhang, Xiaoru; Liu, Mingshuai; Liu, Hongxia; Zhang, Shusheng

    2014-06-15

    A new photoelectrochemical (PEC) biosensor was developed using low-toxic Ag2S QDs as photoelectrochemically active species. Energy levels of Ag2S and Ag2Se QD were compared to explain their differences in the PEC performance. The preparation condition of Ag2S QD was optimized and its structure characterization was measured. Then the developed photoelectric active interface was used to detect glucose and MCF-7 cancer cell and showed the good sensitivity and specificity. Under optimal condition, detection limits of 3.2 × 10(-5)M for glucose and 98 cells/mL for MCF-7 cell were achieved. Thus, the prepared Ag2S QD could serve as an excellent and promising photoelectric active material in the PEC biosensor.

  1. Characteristics of Planar Monopole Antenna on High Impedance Electromagnetic Surface

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Jastram, Nathan; Ponchak, George E.; Franklin, Rhonda R.

    2011-01-01

    This paper presents for the first time measured characteristics of a planar monopole antenna placed directly on a high impedance electromagnetic surface or artificial magnetic conductor (AMC). The return loss and radiation patterns are compared between the antenna in free space, and when placed directly on a perfect electrical conductor (PEC), and on the AMC. The antenna measured in free space has a wide pass band from 3 to 10 GHz. The return loss for the antenna on the PEC is nearly all reflected back and the return loss for the antenna on the AMC has a 10 dB bandwidth from 7.5 to 9.5 GHz. The gain of the antenna in free space, on PEC and on AMC is 1, -12 and 10 dBi, respectively. This indicates that the AMC is working properly, sending all the radiation outward with little loss.

  2. Molecularly chemisorbed intermediate state to oxygen adsorption on Pd{110} [rapid communication

    NASA Astrophysics Data System (ADS)

    Junell, P.; Honkala, K.; Hirsimäki, M.; Valden, M.; Laasonen, K.

    2003-12-01

    Translational energy ( ET) dependence of oxygen (O 2) adsorption on Pd{1 1 0} has been investigated with molecular beam surface scattering (MBSS) experiments. The initial sticking probability ( S0) and adsorption kinetics of oxygen are shown to depend strongly on ET of the incident molecule. An inverse surface temperature dependence of S0 is also observed at low translational energies. Using density-functional theory calculations several O 2 adsorption potential energy curves (PECs) on Pd{1 1 0} were determined. Direct adsorption PECs with an activation barrier and two PECs with a molecular chemisorption state were found. Both experimental and theoretical results indicate a twofold adsorption mechanism. At low ET molecules end up in a very attractive molecularly chemisorbed precursor state from which they eventually dissociate. At higher ET more molecules begin to dissociate via a direct activated adsorption channel.

  3. Application of AWE for RCS Frequency Response Calculations Using Method of Moments

    NASA Technical Reports Server (NTRS)

    Reddy, C. J.; Deshpande, M. D.

    1996-01-01

    An implementation of the Asymptotic Waveform Evaluation (AWE) technique is presented for obtaining the frequency response of the Radar Cross Section (RCS) of arbitrarily shaped, three-dimensional perfect electric conductor (PEC) bodies. An Electric Field Integral Equation (EFIE) is solved using the Method of Moments (MoM) to compute the RCS. The electric current, thus obtained, is expanded in a Taylor series around the frequency of interest. The coefficients of the Taylor series (called 'moments') are obtained using the frequency derivatives of the EFIE. Using the moments, the electric current on the PEC body is obtained over a frequency band. Using the electric current at different frequencies, RCS of the PEC body is obtained over a wide frequency band. Numerical results for a square plate, a cube, and a sphere are presented over a bandwidth. A good agreement between AWE and the exact solution over the bandwidth is observed.

  4. Interaction of participant characteristics and type of AAC with individuals with ASD: a meta-analysis.

    PubMed

    Ganz, Jennifer B; Mason, Rose A; Goodwyn, Fara D; Boles, Margot B; Heath, Amy K; Davis, John L

    2014-11-01

    Individuals with autism spectrum disorders (ASD) and complex communication needs often rely on augmentative and alternative communication (AAC) as a means of functional communication. This meta-analysis investigated how individual characteristics moderate effectiveness of three types of aided AAC: the Picture Exchange Communication System (PECS), speech-generating devices (SGDs), and other picture-based AAC. Effectiveness was measured via the Improvement Rate Difference. Results indicated that AAC has small to moderate effects on speech outcomes, and that SGDs appear to be most effective when considering any outcome measure with individuals with ASD without comorbid intellectual/developmental disorders (IDD). PECS appears to be most effective when considering any outcome measure with individuals with ASD and IDD. SGDs and PECS were the most effective type of AAC for preschoolers, when aggregating across outcome measures. No difference was found between systems for elementary-aged and older individuals.

  5. Brief Report: Randomized test of the efficacy of picture exchange communication system on highly generalized picture exchanges in children with ASD.

    PubMed

    Yoder, Paul J; Lieberman, Rebecca G

    2010-05-01

    A randomized control trial comparing two social-communication interventions in young children with autism examined far-transfer of the use of picture exchange to communicate. Thirty-six children were randomly assigned to one of two treatment conditions, one of which was the Picture Exchange Communication System (PECS). All children had access to picture symbols during assessments. Post-treatment measurement of the number of picture exchanges in a far-transfer, assessment context favored the PECS intervention. These findings were interpreted as support for the hypothesis that the PECS curriculum can successfully teach a generalized means of showing coordinated attention to object and person without requiring eye contact to children with ASD.

  6. Improved photoelectrochemical performance of GaN nanopillar photoanodes.

    PubMed

    Narangari, Parvathala Reddy; Karuturi, Siva Krishna; Lysevych, Mykhaylo; Hoe Tan, Hark; Jagadish, Chennupati

    2017-04-18

    In this work, we report on the photoelectrochemical (PEC) investigation of n-GaN nanopillar (NP) photoanodes fabricated using metal organic chemical vapour deposition and the top-down approach. Substantial improvement in photocurrents is observed for GaN NP photoanodes compared to their planar counterparts. The role of carrier concentration and NP dimensions on the PEC performance of NP photoanodes is further elucidated. Photocurrent density is almost doubled for doped NP photoanodes whereas no improvement is noticed for undoped NP photoanodes. While the diameter of GaN NP is found to influence the onset potential, carrier concentration is found to affect both the onset and overpotential of the electrodes. Optical and electrochemical impedance spectroscopy characterisations are utilised to further explain the PEC results of NP photoanodes. Finally, improvement in the photostability of NP photoanodes with the addition of NiO as a co-catalyst is investigated.

  7. Gate-Tunable Electron Injection Based Organic Light-Emitting Diodes for Low-Cost and Low-Voltage Active Matrix Displays.

    PubMed

    Luan, Xinning; Liu, Jiang; Pei, Qibing; Bazan, Guillermo C; Li, Huaping

    2017-05-24

    Low-cost and low-voltage active matrix displays were fabricated by simply patterning gate electrode arrays on a polymer electrolyte (PE)-coated polymer light-emitting diode (PLED). Structurally, a PE capacitor seamlessly stacked on a PLED by sharing a common Al:LiF composite electrode (PEC|PLED). This monolithic integrated organic optoelectronic device was characterized and interpreted as the tunable work function (surface potential) because of the perturbation of accumulated ions on Al:LiF composite electrode by PEC charging and discharging. The modulation of electron injection by the PEC resulted in increases in the electroluminescent brightness, from <100 cd m(-2) to >8000 cd m(-2), and the external quantum efficiency from <0.025% to 2.4%.

  8. Twofold diabatization of the KRb (1 -2 )1Π complex in the framework of ab initio and deperturbation approaches

    NASA Astrophysics Data System (ADS)

    Kozlov, S. V.; Pazyuk, E. A.; Stolyarov, A. V.

    2016-10-01

    We performed a diabatization of the mutually perturbed 1 1Π and 2 1Π states of KRb based on both electronic structure calculation and direct coupled-channel deperturbation analysis of experimental energies. The potential energy curves (PECs) of the diabatic states and their scalar coupling were constructed from the ab initio adiabatic PECs by analytically integrating the radial <ψ1a d|∂ /∂ R |ψ2a d> matrix element obtained by a finite-difference method. The diabatic potentials and electronic coupling function were refined by the least squares fitting of the rovibronic term values of the 1 1Π ˜2 1Π complex. The empirical PECs combined with the coupling function as well as the diabatized spin-orbit coupling and transition dipole matrix elements are crucial to discovering efficient photoassociation pathways for production of ultracold ground-state KRb molecules.

  9. Photoelectrochemical, impedance and optical data for self Sn-diffusion doped Fe2O3 photoanodes fabricated at high temperature by one and two-step annealing methods

    PubMed Central

    Shinde, Pravin S.; Annamalai, Alagappan; Kim, Ju Hun; Choi, Sun Hee; Lee, Jae Sung; Jang, Jum Suk

    2015-01-01

    The optical, morphological and photoelectrochemical (PEC) properties of transition metal oxide semiconductors are important to understand their influence on water oxidation performance. Herein, we provide experimental evidences for a better understanding of the factors that dictate the interactions of Sn-diffusion doping on the PEC properties of Fe2O3 photoanodes fabricated at high temperature by one- and two-step annealing methods. The synthesis, characterization methods and other experimental details are provided. Limited previous information on the PEC and electrochemical impedance spectroscopic studies has been published. This data article contains Supplementary data, figures and methods related to the research article by Shinde et al. (2015) [1]. Here, we provide a further set of the obtained experimental data results. PMID:26693514

  10. Plasmon enhanced electrocatalytic oxidation of ethanol and organic contaminants on gold/copper iodide composites under visible light irradiation.

    PubMed

    Sun, Mingjuan; Zhai, Chunyang; Hu, Jiayue; Zhu, Mingshan; Pan, Jianguo

    2017-09-28

    In this paper, plasmonic photoelectroncatalyst of gold/copper iodide (Au/CuI) was synthesized and fully characterized. Compared to traditional electrocatalytic procedure under dark condition, the photoelectrocatalytic (PEC) activities of Au/CuI towards ethanol oxidation and organic pollutant degradation were distinctly enhanced under visible light irradiation. The advantages of the PEC process were investigated by photocurrent responses, linear sweep voltammetry, chronoamperometric and chronopotentiometry curves, and electrochemical impedance spectroscopy spectra. Finally, the mechanism of plasmon enhanced PEC performance in ethanol oxidation and organic contaminant degradation under visible light irradiation was proposed. The current studies open a new possibility in the application of ethanol oxidation and organic contaminant degradation by using plasmonic photoelectrocatalysts under visible light irradiation. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Anti-corrosion layer prepared by plasma electrolytic carbonitriding on pure aluminum

    NASA Astrophysics Data System (ADS)

    Wu, Jie; Zhang, Yifan; Liu, Run; Wang, Bin; Hua, Ming; Xue, Wenbin

    2015-08-01

    In this paper, plasma electrolytic carbonitriding (PEC/N) method was applied to pure aluminum for the first time. The spectroscopic characterization of plasma discharge during PEC/N process was analyzed and the electron temperature was calculated in terms of optical emission spectroscopy. The results showed the discharge plasma was in local thermal equilibrium (LTE) state. Electron concentration and electron temperature were about 6 × 1021 m-3 and 4000 K, respectively. The carbonitrided layer contained Al4C3, AlN and Al7C3N3 phases. After PEC/N treatment, the corrosion resistance of pure aluminum was significantly improved, which was related to the formation of nitride phases. This work expands the application of plasma electrolysis technology on the surface modification of low melting point metal.

  12. An auxiliary-field quantum Monte Carlo study of the chromium dimer

    SciTech Connect

    Purwanto, Wirawan Zhang, Shiwei; Krakauer, Henry

    2015-02-14

    The chromium dimer (Cr{sub 2}) presents an outstanding challenge for many-body electronic structure methods. Its complicated nature of binding, with a formal sextuple bond and an unusual potential energy curve (PEC), is emblematic of the competing tendencies and delicate balance found in many strongly correlated materials. We present an accurate calculation of the PEC and ground state properties of Cr{sub 2}, using the auxiliary-field quantum Monte Carlo (AFQMC) method. Unconstrained, exact AFQMC calculations are first carried out for a medium-sized but realistic basis set. Elimination of the remaining finite-basis errors and extrapolation to the complete basis set limit are then achieved with a combination of phaseless and exact AFQMC calculations. Final results for the PEC and spectroscopic constants are in excellent agreement with experiment.

  13. Improved photoelectrochemical performance of GaN nanopillar photoanodes

    NASA Astrophysics Data System (ADS)

    Reddy Narangari, Parvathala; Krishna Karuturi, Siva; Lysevych, Mykhaylo; Tan, Hark Hoe; Jagadish, Chennupati

    2017-04-01

    In this work, we report on the photoelectrochemical (PEC) investigation of n-GaN nanopillar (NP) photoanodes fabricated using metal organic chemical vapour deposition and the top-down approach. Substantial improvement in photocurrents is observed for GaN NP photoanodes compared to their planar counterparts. The role of carrier concentration and NP dimensions on the PEC performance of NP photoanodes is further elucidated. Photocurrent density is almost doubled for doped NP photoanodes whereas no improvement is noticed for undoped NP photoanodes. While the diameter of GaN NP is found to influence the onset potential, carrier concentration is found to affect both the onset and overpotential of the electrodes. Optical and electrochemical impedance spectroscopy characterisations are utilised to further explain the PEC results of NP photoanodes. Finally, improvement in the photostability of NP photoanodes with the addition of NiO as a co-catalyst is investigated.

  14. Occurrence and effects of tire wear particles in the environment--a critical review and an initial risk assessment.

    PubMed

    Wik, Anna; Dave, Göran

    2009-01-01

    This review summarizes the existing knowledge on the occurrence of tire wear particles in the environment, and their ecotoxicological effects. A meta-analysis on tire components in the environment revealed that tire wear particles are present in all environmental compartments, including air, water, soils/sediments, and biota. The maximum Predicted Environmental Concentrations (PECs) of tire wear particles in surface waters range from 0.03 to 56 mg l(-1) and the maximum PECs in sediments range from 0.3 to 155 g kg(-1) d.w. The results from our previous long-term studies with Ceriodaphnia dubia and Pseudokirchneriella subcapitata were used to derive Predicted No Effect Concentrations (PNECs). The upper ranges for PEC/PNEC ratios in water and sediment were >1, meaning that tire wear particles present potential risks for aquatic organisms. We suggest that management should be directed towards development and production of more environmentally friendly tires and improved road runoff treatment.

  15. Photoanode current of large-area MoS₂ ultrathin nanosheets with vertically mesh-shaped structure on indium tin oxide.

    PubMed

    Xu, Xiaoyong; Hu, Jingguo; Yin, Zongyou; Xu, Chunxiang

    2014-04-23

    A large area of hydrothermally grown MoS2 ultrathin nanosheets (NSs) with a vertically mesh-shaped structure on indium tin oxide (ITO) substrate was directly used as the photoanode of a potoelectrochemical (PEC) cell. The photoelectrocatalytic capacity of ultrathin MoS2 NSs was demonstrated, which was attributed not only to the excellent electrocatalytic activity originating from the exposed preferentially active edge sites but also to the superior photoelectric response resulting from the large light absorption of ultrathin MoS2 NSs and from the efficient separation of electron-hole pairs at the ITO/MoS2 interfaces. The significantly enhanced photocurrent indicates that the MoS2 ultrathin NSs can be a promising photoelectrocatalyst for PEC cells, unveiling the potential of MoS2-based PEC cells for solar energy absorption and conversion.

  16. Enhanced photoelectrochemical property of ZnO nanorods array synthesized on reduced graphene oxide for self-powered biosensing application.

    PubMed

    Kang, Zhuo; Gu, Yousong; Yan, Xiaoqin; Bai, Zhiming; Liu, Yichong; Liu, Shuo; Zhang, Xiaohui; Zhang, Zheng; Zhang, Xueji; Zhang, Yue

    2015-02-15

    We have realized the direct synthesis of ZnO nanorods (ZnO NRs) array on reduced graphene layer (rGO), and demonstrated the enhanced photoelectrochemical (PEC) property of the rGO/ZnO based photoanode under UV irradiation compared with the pristine ZnO NRs array. The introduction of the rGO layer resulted in a favorable energy band structure for electron migration, which finally led to the efficient photoinduced charge separation. Such nanostructure was subsequently employed for self-powered PEC biosensing of glutathione in the condition of 0 V bias, with a linear range from 10 to 200 µM, a detection limit of 2.17 µM, as well as excellent selectivity, reproducibility and stability. The results indicated the rGO/ZnO nanostructure is a competitive candidate in the PEC biosensing field.

  17. Induced dipole in vanadium-doped zinc oxide nanosheets and its effects on photoelectrochemical water splitting

    NASA Astrophysics Data System (ADS)

    Lee, Song Mi; Shin, Sung-Ho; Nah, Junghyo; Lee, Min Hyung

    2017-09-01

    Appropriate control of energy band bending at the interface between semiconductors and electrolytes are closely related to performance of photoelectrochemical (PEC) water splitting. Dipoles formed near the surface of semiconductors induces energy band bending at the interface. Energy band bending control has been demonstrated by employing charged molecules and piezoelectric materials. However, chemical and piezoelectric approaches have demerit of chemical instability and inducement of instantaneous dipole, respectively. To overcome these problems, we adopted the ferroelectric material for PEC water splitting, where spontaneous dipoles in the material can be oriented by applying external electric field. In this work, we hydrothermally synthesized vanadium (V)-doped ferroelectric ZnO nanosheets and employed to systematically investigate the dipole effect on performance of V-doped ZnO PEC for water oxidation. Consequently, positively polarized V-doped ZnO photoanode exhibits 125% enhanced water splitting efficiency compared to negatively polarized ones due to favorable band bending for carrier transport from semiconductor to water.

  18. Characterizations and photoelectrochemical properties of Fe2O3 and ZrO2 nanotubes formed by anodic oxidation process

    NASA Astrophysics Data System (ADS)

    Rozana, Monna; Tan, Wai Kian; Matsuda, Atsunori; Lockman, Zainovia

    2017-07-01

    Anodization of Zr and Fe foils in fluoride ethylene glycol produced surface oxide with nanotubular structure. After heat treatment, surface oxide on Fe foil crystalized to predominantly α-Fe2O3 (hematite) and on Zr foil tetragonal/monoclinic ZrO2 was produced. Anodization of both Zr and Fe for anodic nanotubes formation were done in ethylene glycol/NH4F/KOH electrolyte at 50 - 60 V. The anodized foils were used as photoanode in a photoelectrochemical (PEC) cell. At 0.5 V vs Ag/AgCl, photocurrent of a PEC cell comprising of α-Fe2O3 photoanode was 0.22 mA cm-2. PEC with ZrO2 photoanode displayed smaller photocurrent of 0.02 mA cm-2 at 0.5 V in 1M NaOH electrolyte.

  19. Electronic Structure Engineering of Cu2O Film/ZnO Nanorods Array All-Oxide p-n Heterostructure for Enhanced Photoelectrochemical Property and Self-powered Biosensing Application

    NASA Astrophysics Data System (ADS)

    Kang, Zhuo; Yan, Xiaoqin; Wang, Yunfei; Bai, Zhiming; Liu, Yichong; Zhang, Zheng; Lin, Pei; Zhang, Xiaohui; Yuan, Haoge; Zhang, Xueji; Zhang, Yue

    2015-01-01

    We have engineered the electronic structure at the interface between Cu2O and ZnO nanorods (NRs) array, through adjusting the carrier concentration of Cu2O. The electrodeposition of Cu2O at pH 11 acquired the highest carrier concentration, resulting in the largest interfacial electric field between Cu2O and ZnO, which finally led to the highest separation efficiency of photogenerated charge carriers. The optimized Cu2O/ZnO NRs array p-n heterostructures exhibited enhanced PEC performance, such as elevated photocurrent and photoconversion efficiency, as well as excellent sensing performance for the sensitive detection of glutathione (GSH) in PBS buffer even at applied bias of 0 V which made the device self-powered. Besides, the favorable selectivity, high reproducibility and extremely wide detection range, make such heterostructure a promising candidate for PEC biosensing applications, probably for the extended field of PEC water splitting or other solar photovoltaic beacons.

  20. W ion implantation boosting visible-light photoelectrochemical water splitting over ZnO nanorod arrays

    NASA Astrophysics Data System (ADS)

    Cai, Li; Zhou, Wu; Ren, Feng; Chen, Jie; Cai, Guangxu; Liu, Yichao; Guan, Xiangjiu; Shen, Shaohua

    2017-01-01

    W ions were doped into ZnO nanorod arrays hydrothermally grown on the F-doped tin-oxide-coated glass substrates via an advanced ion implantation technique for photoelectrochemical (PEC) water splitting under visible light. It was found that W incorporation could narrow the bandgap of ZnO and shift the optical absorption into visible light regions obviously, with the one-dimensional nanorod structure maintained for superior charge transfer. As a result, the W-doped ZnO nanorod arrays exhibit considerable PEC performance relative to ZnO nanorod arrays under visible light illumination (λ>420 nm), with photocurrent density achieved up to 15.2 μA/cm2 at 1.0 V (versus Ag/AgCl). The obtained PEC properties indicate that ion implantation can be an alternative approach to develop unique materials for efficient solar energy conversion.

  1. Conservative management of migrated percutaneous endoscopic colostomy tube

    PubMed Central

    Chase, Thomas J.G.; Luck, Joshua; Harris, Lauren S.; Bashir, Gareth

    2017-01-01

    A 68-year-old male nursing home resident presented following dislodgement of a percutaneous endoscopic colostomy (PEC) tube originally sited to prevent recurrent sigmoid volvulus. Computed tomography demonstrated tube migration into the lumen of the recto-sigmoid junction, where it remained for 12 days before passing spontaneously. During this period, the patient remained asymptomatic; the residual colocutaneous fistula functioned as a decompressive valve. Originally, the patient was due to be discharged with early flexible sigmoidoscopy follow-up. However, complex social issues delayed discharge. During his admission, a second PEC tube was successfully inserted next to the previous colostomy site without complication. This is an unusual case and no similar episodes of asymptomatic PEC migration have been reported. We demonstrate that such cases may be offered an appropriate trial of conservative management. Here, we describe our experience and critically appraise the literature. PMID:28064245

  2. Spin-Coated Polyelectrolyte Coacervate Films.

    PubMed

    Kelly, Kristopher D; Schlenoff, Joseph B

    2015-07-01

    Thin films of complexes made from oppositely charged polyelectrolytes have applications as supported membranes for separations, cell growth substrates, anticorrosion coatings, biocompatible coatings, and drug release media, among others. The relatively recent technique of layer-by-layer assembly reliably yields conformal coatings on substrates but is impractically slow for films with thickness greater than about 1 μm, even when accelerated many fold by spraying and/or spin assembly. In the present work, thin, uniform, smooth films of a polyelectrolyte complex (PEC) are rapidly made by spin-coating a polyelectrolyte coacervate, a strongly hydrated viscoelastic liquidlike form of PEC, on a substrate. While the apparatus used to deposit the PEC film is conventional, the behavior of the coacervate, especially the response to salt concentration, is highly nontraditional. After glassification by immersion in water, spun-on films may be released from their substrates to yield free-standing membranes of thickness in the micrometer range.

  3. Interplay of light transmission and catalytic exchange current in photoelectrochemical systems

    SciTech Connect

    Fountaine, Katherine T.; Lewerenz, Hans J.; Atwater, Harry A.

    2014-10-27

    We develop an analytic current-voltage expression for a variable junction photoelectrochemical (PEC) cell and use it to investigate and illustrate the influence of the optical and electrical properties of catalysts on the optoelectronic performance of PEC devices. Specifically, the model enables a simple, yet accurate accounting of nanostructured catalyst optical and electrical properties through incorporation of an optical transmission factor and active catalytic area factor. We demonstrate the utility of this model via the output power characteristics of an exemplary dual tandem solar cell with indium gallium phosphide and indium gallium arsenide absorbers with varying rhodium catalyst nanoparticle loading. The approach highlights the importance of considering interactions between independently optimized components for optimal PEC device design.

  4. Photoelectrochemical sensor for pentachlorophenol on microfluidic paper-based analytical device based on the molecular imprinting technique.

    PubMed

    Sun, Guoqiang; Wang, Panpan; Ge, Shenguang; Ge, Lei; Yu, Jinghua; Yan, Mei

    2014-06-15

    Combining microfluidic paper-based analytical device (μ-PAD) and the molecular imprinting technique, a visible light photoelectrochemical (PEC) sensing platform for the detection of pentachlorophenol (PCP) was established on gold nanoparticles (AuNPs) decorated paper working electrode using polypyrrole-functionalized ZnO nanoparticles. Ascorbic acid (AA) was exploited as an efficient and nontoxic electron donor for scavenging photogenerated holes under mild solution medium and facilitating the generation of stable photocurrent. The microfluidic molecular imprinted polymer-based PEC analytical origami device is developed for the detection of PCP in the linear range from 0.01 ng mL(-1) to 100 ng mL(-1) with a low detection limit of 4 pg mL(-1). This disposable microfluidic PEC origami device would provide a new platform for sensitive, specific, and multiplex assay in public health, environmental monitoring, and the developing world.

  5. Pulsed Eddy Current Non-destructive Testing and Evaluation: A Review

    NASA Astrophysics Data System (ADS)

    Sophian, Ali; Tian, Guiyun; Fan, Mengbao

    2017-05-01

    Pulsed eddy current (PEC) non-destructive testing and evaluation (NDT&E) has been around for some time and it is still attracting extensive attention from researchers around the globe, which can be witnessed through the reports reviewed in this paper. Thanks to its richness of spectral components, various applications of this technique have been proposed and reported in the literature covering both structural integrity inspection and material characterization in various industrial sectors. To support its development and for better understanding of the phenomena around the transient induced eddy currents, attempts for its modelling both analytically and numerically have been made by researchers around the world. This review is an attempt to capture the state-of-the-art development and applications of PEC, especially in the last 15 years and it is not intended to be exhaustive. Future challenges and opportunities for PEC NDT&E are also presented.

  6. Enhanced ferroelectric photoelectrochemical properties of polycrystalline BiFeO{sub 3} film by decorating with Ag nanoparticles

    SciTech Connect

    Liu, Qing; Shen, Mingrong; Fang, Liang; Zhou, Yang; You, Lu; Wang, Junling

    2016-01-11

    Polycrystalline BiFeO{sub 3} (BFO) films are fabricated on Pt/Ti/SiO{sub 2}/Si(100) substrate as photoelectrode using sol-gel method. The microstructure, optical, and photoelectrochemical (PEC) properties of the films are characterized and optimized by controlling the film thickness. Moreover, the PEC properties of the BFO films are dependent on ferroelectric polarization, which is mainly ascribed to the modulation of band structure at the BFO/electrolyte interface by the polarization. Further enhancement of PEC properties is obtained by decorating the samples with appropriate amounts of Ag nanoparticles, which is attributed to the reduced electron-hole recombination, and localized surface plasmon resonance effect of Ag nanoparticles.

  7. Classical and Mexican hat-type potential energy curve for the hydrogen molecule from a confined Kratzer oscillator

    NASA Astrophysics Data System (ADS)

    van Hooydonk, G.

    2016-03-01

    We review harmonic oscillator theory for closed, stable quantum systems. The H2 potential energy curve (PEC) of Mexican hat-type, calculated with a confined Kratzer oscillator, is better than the Rydberg-Klein-Rees (RKR) H2 PEC. Compared with QM, the theory of chemical bonding is simplified, since a confined Kratzer oscillator can also lead to the long sought for universal function, once called the Holy Grail of Molecular Spectroscopy. This is validated by reducing PECs for different bonds H2, HF, I2, N2 and O2 to a single one. The equal probability for H2, originating either from HA + HB or HB + HA, is quantified with a Gauss probability density function. At the Bohr scale, a confined harmonic oscillator behaves properly at the extremes of bound two-nucleon quantum systems.

  8. Heterostructured ZnFe2O4/TiO2 nanotube arrays with remarkable visible-light photoelectrocatalytic performance and stability.

    PubMed

    Xie, Shan; Ouyang, Ke; Lao, Yueming; He, Peihao; Wang, Qun

    2017-05-01

    A series of heterostructured ZnFe2O4/TiO2-nanotube arrays (NTAs) with remarkable visible-light photoelectrocatalytic (PEC) activity were successfully prepared via a two-step process of anodization and impregnation, followed by annealing. The structure and morphology of the as-prepared ZnFe2O4/TiO2-NTAs samples, PEC degradation abilities and photoelectrochemical performances, as well as long-term stabilities toward degradation of methyl orange (MO) solution under visible-light irradiation were deeply investigated. Results showed that forming a heterojunction by combination of TiO2-NTAs with ZnFe2O4 successfully extended the absorption edge of TiO2-NTAs to visible-light region. Among all the ZnFe2O4/TiO2-NTAs samples, the 2-ZnFe2O4/TiO2-NTAs sample, named ZT(2), obtained the best PEC activity and the highest photocurrent density under visible-light irradiation. Moreover, the ZT(2) sample retained a good reproducibility and high stability after 20days of PEC degradation. The outstanding visible-light PEC activity and photocurrent response of the ZT(2) sample were attributed to the proper amount of ZnFe2O4 nanoparticles loaded onto the TiO2-NTAs, which not only dramatically improved the visible-light absorption of TiO2-NTAs, but also assisted the separation of photo-induced electron-hole pairs and reduced their recombination by forming a ZnFe2O4/TiO2-NTAs heterojunction. The reaction mechanism responsible for the enhanced visible-light PEC performance of the ZnFe2O4/TiO2-NTAs heterostructure was also discussed.

  9. Peri/Epicellular Protein Disulfide Isomerase Sustains Vascular Lumen Caliber Through an Anticonstrictive Remodeling Effect.

    PubMed

    Tanaka, Leonardo Y; Araújo, Haniel A; Hironaka, Gustavo K; Araujo, Thaís L S; Takimura, Celso K; Rodriguez, Andres I; Casagrande, Annelise S; Gutierrez, Paulo S; Lemos-Neto, Pedro Alves; Laurindo, Francisco R M

    2016-03-01

    Whole-vessel remodeling critically determines lumen caliber in vascular (patho)physiology, and it is reportedly redox-dependent. We hypothesized that the cell-surface pool of the endoplasmic reticulum redox chaperone protein disulfide isomerase-A1 (peri/epicellular=pecPDI), which is known to support thrombosis, also regulates disease-associated vascular architecture. In human coronary atheromas, PDI expression inversely correlated with constrictive remodeling and plaque stability. In a rabbit iliac artery overdistension model, there was unusually high PDI upregulation (≈25-fold versus basal, 14 days postinjury), involving both intracellular and pecPDI. PecPDI neutralization with distinct anti-PDI antibodies did not enhance endoplasmic reticulum stress or apoptosis. In vivo pecPDI neutralization with PDI antibody-containing perivascular gel from days 12 to 14 post injury promoted 25% decrease in the maximally dilated arteriographic vascular caliber. There was corresponding whole-vessel circumference loss using optical coherence tomography without change in neointima, which indicates constrictive remodeling. This was accompanied by decreased hydrogen peroxide generation. Constrictive remodeling was corroborated by marked changes in collagen organization, that is, switching from circumferential to radial fiber orientation and to a more rigid fiber type. The cytoskeleton architecture was also disrupted; there was a loss of stress fiber coherent organization and a switch from thin to medium thickness actin fibers, all leading to impaired viscoelastic ductility. Total and PDI-associated expressions of β1-integrin, and levels of reduced cell-surface β1-integrin, were diminished after PDI antibody treatment, implicating β1-integrin as a likely pecPDI target during vessel repair. Indeed, focal adhesion kinase phosphorylation, a downstream β1-integrin effector, was decreased by PDI antibody. Thus, the upregulated pecPDI pool tunes matrix/cytoskeleton reshaping to

  10. Graphitic Carbon Nitride Sensitized with CdS Quantum Dots for Visible-Light-Driven Photoelectrochemical Aptasensing of Tetracycline.

    PubMed

    Liu, Yong; Yan, Kai; Zhang, Jingdong

    2015-11-17

    Graphitic carbon nitride (g-C3N4) is a new type of metal-free semiconducting material with promising applications in photocatalytic and photoelectrochemical (PEC) devices. In the present work, g-C3N4 coupled with CdS quantum dots (QDs) was synthesized and served as highly efficient photoactive species in a PEC sensor. The surface morphological analysis showed that CdS QDs with a size of ca. 4 nm were grafted on the surface of g-C3N4 with closely contacted interfaces. The UV-visible diffuse reflection spectra (DRS) indicated that the absorption of g-C3N4 in the visible region was enhanced by CdS QDs. As a result, g-C3N4-CdS nanocomposites demonstrated higher PEC activity as compared with either pristine g-C3N4 or CdS QDs. When g-C3N4-CdS nanocomposites were utilized as transducer and tetracycline (TET)-binding aptamer was immobilized as biorecognition element, a visible light-driven PEC aptasensing platform for TET determination was readily fabricated. The sensor showed a linear PEC response to TET in the concentration range from 10 to 250 nM with a detection limit (3S/N) of 5.3 nM. Thus, g-C3N4 sensitized with CdS QDs was successfully demonstrated as useful photoactive nanomaterials for developing a highly sensitive and selective PEC aptasensor.

  11. Effect of caffeic acid esters on carcinogen-induced mutagenicity and human colon adenocarcinoma cell growth.

    PubMed

    Rao, C V; Desai, D; Kaul, B; Amin, S; Reddy, B S

    1992-11-16

    Propolis, a honey bee hive product, is thought to exhibit a broad spectrum of activities including antibiotic, antiviral, anti-inflammatory and tumor growth inhibition; some of the observed biological activities may be due to caffeic acid (cinnamic acid) esters that are present in propolis. In the present study we synthesized three caffeic acid esters, namely methyl caffeate (MC), phenylethyl caffeate (PEC) and phenylethyl dimethylcaffeate (PEDMC) and tested them against the 3,2'-dimethyl-4-aminobiphenyl, (DMAB, a colon and mammary carcinogen)-induced mutagenicity in Salmonella typhimurium strains TA 98 and TA 100. Also, the effect of these agents on the growth of human colon adenocarcinoma, HT-29 cells and activities of ornithine decarboxylase (ODC) and protein tyrosine kinase (PTK) was studied. Mutagenicity was induced in Salmonella typhimurium strains TA 98 and TA 100 plus S9 activation using 5 and 10 micrograms DMAB and antimutagenic activities of 0-150 microM MC, 0-60 microM PEC and 0-80 microM PEDMC were determined. The results indicate that MC, PEC and PEDMC were not mutagenic in the Salmonella tester system. DMAB-induced mutagenicity was significantly inhibited with 150 microM MC, 40-60 microM PEC and 40-80 microM PEDMC in both tester systems. Treatment of HT-29 colon adenocarcinoma cells with > 150 microM MC, 30 microM PEC and 20 microM PEDMC significantly inhibited the cell growth and syntheses of RNA, DNA and protein. ODC and PTK activities were also inhibited in HT-29 cells treated with different concentrations of MC, PEC and PEDMC. These results demonstrate that caffeic acid esters which are present in Propolis possess chemopreventive properties when tested in short-term assay systems.

  12. Self-ordering titania nanotube arrays: Electrochemical anodization, functionalization, and application

    NASA Astrophysics Data System (ADS)

    Smith, York Reed

    Hydrogen is envisioned as a viable fuel of the future. Photoelectrochemical (PEC) hydrogen generation by water splitting reaction is the most promising method to obtain renewable hydrogen. The U.S. Department of Energy has determined that for PEC hydrogen to be economically feasible, and competitive with steam reforming hydrogen production, a solar-to-hydrogen efficiency of 10% maintained for 1,000 hours of operation is required. Selection of durable photo-electrodes capable of withstanding the harsh aqueous environment in PEC hydrogen generation is an important factor. Semiconductor nanostructured metal oxides, such as titanium dioxide, are generally more stable in such environments, making them suitable candidate materials. In the present investigation, self-organizing nanotubular titanium dioxide synthesized by electrochemical anodization and heterostructures thereof were examined for PEC hydrogen generation. In the first part, new synthesis methods were explored such as light-assisted anodization, surface treatment prior to anodization to achieve hierarchical nanotubular titanium dioxide, and binary acid anodization for in situ metal doping. A mechanism for pore nucleation and nanotube wall separation has also been proposed. In the second part, titania nanotubes were sensitized with nanocrystalline CdO, CdS, and Mn2+ or Co2+ doped CdS as visible light absorber layers. The material properties were examined using different characterization techniques such as scanning electron microscopy (SEM), x-ray diffraction (XRD), ultra violet-visible (UV-vis) photospectroscopy, x-ray photon spectroscopy (XPS), and Raman spectroscopy. The PEC activity of the photoanodes was examined under simulated air mass (AM) 1.5 irradiation. Electrochemical impedance spectroscopy and Mott-Schotty analysis were also used to ascertain the PEC results and correlate with material properties.

  13. The interleukin-2 receptor α chain (CD25) plays an important role in regulating monocyte-derived CD40 expression during anti-porcine cellular responses.

    PubMed

    Sun, Z-G; Wang, Z; Zhu, L-M; Fang, Y-S; Yu, L-Z; Xu, H

    2012-05-01

    Long-term xenograft survival is limited by delayed xenograft rejection, and monocytes are thought to play an important role in this process. Although typically considered a T cell surface marker, interleukin 2 the receptor chain CD25 is also functional on monocytes. We hypothesized that CD25 expression on monocytes functions to augment monocyte activation in xeno-specific cellular responses. Xenogeneic mixed lymphocyte-endothelial cell reactions were used to study the role of CD25 in facilitating xenogeneic cell-mediated immune responses an in vitro. We also tested the effect of the anti-CD25 antibody daclizumab on monocyte-mediated T cell activation during xeno-specific cellular responses. Co-culture with porcine endothelial cells (PEC) elicited a pronounced proliferative response by human peripheral blood mononuclear cells (PBMC) that was accompanied by upregulation of CD25 and CD40 on CD14(+) monocytes. CD4(+) cells proliferated in response to PEC-conditioned monocytes, while blockade of CD25 with daclizumab reduced CD4(+) cell proliferation in the presence of PEC-conditioned monocytes. In addition, daclizumab inhibited proliferation of PBMC in responses to PEC. Analysis of monocytes from PBMC-PEC cocultures by flow cytometry indicated that daclizumab inhibited CD40 upregulation on PEC-activated monocytes. These data demonstrate that CD25 blockade prevents xenogeneic cellular responses by directly blocking CD25 expression on both activated T cells and monocytes. CD25 blockade on T cells or monocytes may indirectly affect upregulation of CD40 on xenoreactive monocytes. Our data strengthen the rationale for incorporating CD25 directed therapy in discordant xenotransplantation.

  14. Mechanisms Involved in Acquisition of blaNDM Genes by IncA/C2 and IncFIIY Plasmids.

    PubMed

    Wailan, Alexander M; Sidjabat, Hanna E; Yam, Wan Keat; Alikhan, Nabil-Fareed; Petty, Nicola K; Sartor, Anna L; Williamson, Deborah A; Forde, Brian M; Schembri, Mark A; Beatson, Scott A; Paterson, David L; Walsh, Timothy R; Partridge, Sally R

    2016-07-01

    blaNDM genes confer carbapenem resistance and have been identified on transferable plasmids belonging to different incompatibility (Inc) groups. Here we present the complete sequences of four plasmids carrying a blaNDM gene, pKP1-NDM-1, pEC2-NDM-3, pECL3-NDM-1, and pEC4-NDM-6, from four clinical samples originating from four different patients. Different plasmids carry segments that align to different parts of the blaNDM region found on Acinetobacter plasmids. pKP1-NDM-1 and pEC2-NDM-3, from Klebsiella pneumoniae and Escherichia coli, respectively, were identified as type 1 IncA/C2 plasmids with almost identical backbones. Different regions carrying blaNDM are inserted in different locations in the antibiotic resistance island known as ARI-A, and ISCR1 may have been involved in the acquisition of blaNDM-3 by pEC2-NDM-3. pECL3-NDM-1 and pEC4-NDM-6, from Enterobacter cloacae and E. coli, respectively, have similar IncFIIY backbones, but different regions carrying blaNDM are found in different locations. Tn3-derived inverted-repeat transposable elements (TIME) appear to have been involved in the acquisition of blaNDM-6 by pEC4-NDM-6 and the rmtC 16S rRNA methylase gene by IncFIIY plasmids. Characterization of these plasmids further demonstrates that even very closely related plasmids may have acquired blaNDM genes by different mechanisms. These findings also illustrate the complex relationships between antimicrobial resistance genes, transposable elements, and plasmids and provide insights into the possible routes for transmission of blaNDM genes among species of the Enterobacteriaceae family.

  15. Numerical investigation on the performance of fin and tube heat exchangers using rectangular vortex generators

    NASA Astrophysics Data System (ADS)

    Zeeshan, Mohd; Hazarika, Saheera Azmi; Nath, Sujit; Bhanja, Dipankar

    2017-07-01

    In the present work, a 3-D numerical investigation has been performed to explore the effect of attack angles on the thermal-hydraulic performance of fin and tube heat exchanger (FTHE) using rectangular winglet pairs (RWPs). RWPs are placed adjacent to the tubes and three attack angels are considered for the study i.e. 5°, 15° and 25°. The effect of attack angles are examined on the heat transfer characteristics as well as in pressure drop penalty with airside Reynolds number Rea ranges from 500 to 900. Two performance evaluation criteria namely PEC1 i.e. area goodness factor (j/f) and PEC2 i.e. heat transfer rate per unit fan power consumption (Q/Pf) are considered for the performance evaluation. Furthermore, MOORA method is applied to obtain the performance order of FTHE configurations by taking PEC1 and PEC2 as beneficial attributes and fan power Pf as a non-beneficial attribute, keeping equal importance to each attribute. The results show that 5° attack angle provides the better performance in terms of PEC1 as heat transfer coefficient is increased by 27.70% at Rea=500 and 32.73% at Rea=900 respectively with 13.01% increased pressure drop penalty at Rea=500 and 14.26% at Rea=900 respectively. In terms of PEC2, though the 5° attack angle provides the high values of Q/Pf factor among the 15° and 25° attack angles, but it is found insignificant to replace the baseline configuration i.e. plain fin and tube heat exchanger configuration without vortex generators. Moreover, in MOORA optimization analysis also, it is found that 5° attack angle provides the better thermal-hydraulic performance.

  16. Matrix metalloproteinase-9 expression is enhanced in renal parietal epithelial cells of zucker diabetic Fatty rats and is induced by albumin in in vitro primary parietal cell culture.

    PubMed

    Zhang, Yuanyuan; George, Jasmine; Li, Yun; Olufade, Rebecca; Zhao, Xueying

    2015-01-01

    As a subfamily of matrix metalloproteinases (MMPs), gelatinases including MMP-2 and MMP-9 play an important role in remodeling and homeostasis of the extracellular matrix. However, conflicting results have been reported regarding their expression level and activity in the diabetic kidney. This study investigated whether and how MMP-9 expression and activity were changed in glomerular epithelial cells upon albumin overload. In situ zymography, immunostaining and Western blot for renal MMP gelatinolytic activity and MMP-9 protein expression were performed in Zucker lean and Zucker diabetic rats. Confocal microscopy revealed a focal increase in gelatinase activity and MMP-9 protein in the glomeruli of diabetic rats. Increased glomerular MMP-9 staining was mainly observed in hyperplastic parietal epithelial cells (PECs) expressing claudin-1 in the diabetic kidneys. Interestingly, increased parietal MMP-9 was often accompanied by decreased staining for podocyte markers (nephrin and podocalyxin) in the sclerotic area of affected glomeruli in diabetic rats. Additionally, urinary excretion of podocyte marker proteins was significantly increased in association with the levels of MMP-9 and albumin in the urine of diabetic animals. To evaluate the direct effect of albumin on expression and activity of MMP-9, primary cultured rat glomerular PECs were incubated with rat serum albumin (0.25 - 1 mg/ml) for 24 - 48 hrs. MMP-9 mRNA levels were significantly increased following albumin treatment. Meanwhile, albumin administration resulted in a dose-dependent increase in MMP-9 protein and activity in culture supernatants of PECs. Moreover, albumin activated p44/42 mitogen-activated protein kinase (MAPK) in PECs. Inhibition of p44/42 MAPK suppressed albumin-induced MMP-9 secretion from glomerular PECs. Taken together, we have demonstrated that an up-regulation of MMP-9 in activated parietal epithelium is associated with a loss of adjacent podocytes in progressive diabetic nephropathy

  17. Photoelectrochemical water reduction over wide gap (Ag,Cu)(In,Ga)S2 thin film photocathodes.

    PubMed

    Septina, Wilman; Sugimoto, Minori; Chao, Ding; Shen, Qing; Nakatsuka, Shigeru; Nose, Yoshitaro; Harada, Takashi; Ikeda, Shigeru

    2017-05-17

    The effects of partial replacement of Cu with Ag in a Cu(In,Ga)S2 (CIGS) thin film on its structural, optical, electrostructural, and photoelectrochemical (PEC) properties were investigated, in order to improve its performance for PEC water reduction under sunlight illumination. Results from X-ray diffraction (XRD) analyses revealed the successful partial replacement of Cu with Ag to form solid-solutions with different Ag/(Ag + Cu) ratios (A(x)CIGS, x = Ag/(Ag + Cu) = 0.1, 0.2, 0.3 and 0.4), as confirmed by a gradual change in the (112) reflections to smaller 2θ angles with increasing Ag/(Ag + Cu) ratio. Analyses of the photoabsorption properties of the materials using photoacoustic spectroscopy indicated changes in the band gap energies associated with increasing the Ag/(Ag + Cu) ratio. In addition, valence band maximum potentials of A(x)CIGS were deepened gradually with increasing Ag/(Ag + Cu) ratio. After modifying these A(x)CIGS films with a CdS ultrathin (ca. 70 nm) layer and a Pt catalyst, the PEC water reduction properties were evaluated in an electrolyte solution with the pH adjusted to 6.5, under simulated sunlight (AM 1.5G) radiation. Compared to the CdS- and Pt-modified Ag-free A(x)CIGS (A(0)CIGS) films, appreciable enhancements in the PEC properties were observed for electrodes based on A(x)CIGS (x > 0) films, and the best PEC performance was obtained for the electrode based on the A(0.2)CIGS film. However, the electrode derived from the A(x)CIGS film with Ag/(Ag + Cu) ratios higher than 0.3 showed diminished PEC properties due to the partial conversion of its semiconducting properties from p-type to n-type.

  18. Magnetofluorescent probe of superparamagnetic iron oxide nanoparticles modified with poly(TMSMA-r-PEGMA-r-Eu(NTA)3(MMA)(TOPO)3).

    PubMed

    Kim, Min Cheol; Kang, Bo-Sun; Sohn, Youngjoo; Tae, Ki-Sik; Lee, Hyun-Ju; Kim, Do Kyung; Chang, Yun Seung

    2014-11-01

    In this study, hybrid magnetofluorescent structures composed of organic moiety of poly(TMSMA-r-PEGMA) for biomolecules-resistant surfaces and methyl methacrylate for conjugation of europium complex inorganic moiety of magnetic nanoparticles are reported. Lanthanide complex of europium ion with 4,4,4-Trifluoro-1-(2-naphthyl)-1,3-butanedione (NTA) and trioctylphosphine oxide (TOPO)[Eu(NTA)3(TOPO)3] were incorporated into poly(TMSMA-r-PEGMA-r-MMA) matrix. Afterward, superparamagnetic iron oxide nanoparticles (SPIONs) were coated with as prepared polymeric europium complex (PEC) to construct hierarchical structure of magnetofluorescent probe. The PL spectra of the PEC@SPIONs excited by UV light showed characteristic emission behavior with a hypersensitive transition 5D0 --> 7F2 at 621 nm. About a 20% quenching in the intensity of the emission peak at 621 nm was found after the addition of SPIONs. Interestingly, when the concentration of PEC against SPIONs is increased, the hypersensitive transition 5D0 --> 7F2 at 621 nm is linearly increased, while 5D1 --> 7F6 at 700 nm is linearly decreased. The cytotoxic effect of PEC@SPIONs was evaluated with U373MG cell by the MTT assay of PEC@SPIONs in cell proliferation. The cell viability in the range of 10-200 ug/ml was more than 80%. No significant difference in cell proliferation until the concentration of 300 ug/ml (77.61 ± 3.33%). The cellular uptake of PEC@SPIONs evaluated by confocal microscopy showed that the magnetofluorescent nanoparticles were internalized extensively in the cytoplasmic region.

  19. Mechanisms Involved in Acquisition of blaNDM Genes by IncA/C2 and IncFIIY Plasmids

    PubMed Central

    Sidjabat, Hanna E.; Yam, Wan Keat; Alikhan, Nabil-Fareed; Petty, Nicola K.; Sartor, Anna L.; Williamson, Deborah A.; Forde, Brian M.; Beatson, Scott A.; Paterson, David L.; Walsh, Timothy R.

    2016-01-01

    blaNDM genes confer carbapenem resistance and have been identified on transferable plasmids belonging to different incompatibility (Inc) groups. Here we present the complete sequences of four plasmids carrying a blaNDM gene, pKP1-NDM-1, pEC2-NDM-3, pECL3-NDM-1, and pEC4-NDM-6, from four clinical samples originating from four different patients. Different plasmids carry segments that align to different parts of the blaNDM region found on Acinetobacter plasmids. pKP1-NDM-1 and pEC2-NDM-3, from Klebsiella pneumoniae and Escherichia coli, respectively, were identified as type 1 IncA/C2 plasmids with almost identical backbones. Different regions carrying blaNDM are inserted in different locations in the antibiotic resistance island known as ARI-A, and ISCR1 may have been involved in the acquisition of blaNDM-3 by pEC2-NDM-3. pECL3-NDM-1 and pEC4-NDM-6, from Enterobacter cloacae and E. coli, respectively, have similar IncFIIY backbones, but different regions carrying blaNDM are found in different locations. Tn3-derived inverted-repeat transposable elements (TIME) appear to have been involved in the acquisition of blaNDM-6 by pEC4-NDM-6 and the rmtC 16S rRNA methylase gene by IncFIIY plasmids. Characterization of these plasmids further demonstrates that even very closely related plasmids may have acquired blaNDM genes by different mechanisms. These findings also illustrate the complex relationships between antimicrobial resistance genes, transposable elements, and plasmids and provide insights into the possible routes for transmission of blaNDM genes among species of the Enterobacteriaceae family. PMID:27114281

  20. Examination of the Source and Extended Virulence Genotypes of Escherichia coli Contaminating Retail Poultry Meat

    PubMed Central

    Johnson, Timothy J.; Logue, Catherine M.; Wannemuehler, Yvonne; Kariyawasam, Subhashinie; Doetkott, Curt; DebRoy, Chitrita; White, David G.

    2009-01-01

    Abstract Extraintestinal pathogenic Escherichia coli (ExPEC) are major players in human urinary tract infections, neonatal bacterial meningitis, and sepsis. Recently, it has been suggested that there might be a zoonotic component to these infections. To determine whether the E. coli contaminating retail poultry are possible extraintestinal pathogens, and to ascertain the source of these contaminants, they were assessed for their genetic similarities to E. coli incriminated in colibacillosis (avian pathogenic E. coli [APEC]), E. coli isolated from multiple locations of apparently healthy birds at slaughter, and human ExPEC. It was anticipated that the retail poultry isolates would most closely resemble avian fecal E. coli since only apparently healthy birds are slaughtered, and fecal contamination of carcasses is the presumed source of meat contamination. Surprisingly, this supposition proved incorrect, as the retail poultry isolates exhibited gene profiles more similar to APEC than to fecal isolates. These isolates contained a number of ExPEC-associated genes, including those associated with ColV virulence plasmids, and many belonged to the B2 phylogenetic group, known to be virulent in human hosts. Additionally, E. coli isolated from the crops and gizzards of apparently healthy birds at slaughter also contained a higher proportion of ExPEC-associated genes than did the avian fecal isolates examined. Such similarities suggest that the widely held beliefs about the sources of poultry contamination may need to be reassessed. Also, the presence of ExPEC-like clones on retail poultry meat means that we cannot yet rule out poultry as a source of ExPEC human disease. PMID:19580453

  1. Cross-validation of a portable, six-degree-of-freedom load cell for use in lower-limb prosthetics research.

    PubMed

    Koehler, Sara R; Dhaher, Yasin Y; Hansen, Andrew H

    2014-04-11

    The iPecs load cell is a lightweight, six-degree-of-freedom force transducer designed to fit easily into an endoskeletal prosthesis via a universal mounting interface. Unlike earlier tethered systems, it is capable of wireless data transmission and on-board memory storage, which facilitate its use in both clinical and real-world settings. To date, however, the validity of the iPecs load cell has not been rigorously established, particularly for loading conditions that represent typical prosthesis use. The aim of this study was to assess the accuracy of an iPecs load cell during in situ human subject testing by cross-validating its force and moment measurements with those of a typical gait analysis laboratory. Specifically, the gait mechanics of a single person with transtibial amputation were simultaneously measured using an iPecs load cell, multiple floor-mounted force platforms, and a three-dimensional motion capture system. Overall, the forces and moments measured by the iPecs were highly correlated with those measured by the gait analysis laboratory (r>0.86) and RMSEs were less than 3.4% and 5.2% full scale output across all force and moment channels, respectively. Despite this favorable comparison, however, the results of a sensitivity analysis suggest that care should be taken to accurately identify the axes and instrumentation center of the load cell in situations where iPecs data will be interpreted in a coordinate system other than its own (e.g., inverse dynamics analysis).

  2. Outcomes of rapid corticosteroid tapering in acute eosinophilic pneumonia patients with initial eosinophilia.

    PubMed

    Jhun, Byung Woo; Kim, Se Jin; Kim, Kang; Lee, Ji Eun

    2015-11-01

    Studies have shown that patients with acute eosinophilic pneumonia (AEP) and with initial eosinophilia have a milder disease than those with an initial normal peripheral eosinophil count (PEC). We investigated the effect of a rapid corticosteroid tapering strategy in AEP patients with initial eosinophilia. We performed a prospective cohort study in patients with AEP with initial eosinophilia (n = 14) who stopped corticosteroid treatment after achieving clinical stabilization compared with AEP patients with an initial normal PEC (n = 45) who received 2-week treatment with corticosteroid. In total, 59 AEP patients were identified. The median duration of corticosteroid treatment was 4 days (interquartile ranges (IQR), 3-4) in patients with initial eosinophilia and 14 (IQR, 14-14) days in patients with initial normal PEC. No treatment failure occurred in the group with initial eosinophilia; one treatment failure case occurred in the group with an initially normal PEC. The median time to overall clinical stabilization was 3 days, and time to complete resolution of all symptoms and clinical instabilities from diagnosis was 4 days in AEP patients with initial eosinophilia. Both were significantly shorter than those) in the initially normal PEC group, which were 5 and 7 days respectively (both P < 0.001). Adverse effects were lower in AEP patients with initial eosinophilia, and additional medications to relieve adverse effects were only needed in AEP patients with initially normal PEC. Rapid corticosteroid tapering may be an acceptable treatment strategy for managing AEP patients with initial eosinophilia. © 2015 Asian Pacific Society of Respirology.

  3. Silicon nanostructures-induced photoelectrochemical solar water splitting for energy applications

    SciTech Connect

    Dadwal, U.; Singh, R.; Ranjan, Neha

    2016-05-23

    We study the photoelectrochemical (PEC) solar water splitting assisted with synthesized nanostructures. Si nanowires decorated with silver dendrite nanostructures have been synthesized using metal assisted wet chemical etching of (100) Si wafer. Etching has been carried out in an aqueous solution consisting of 5M HF and 0.02M AgNO{sub 3}. Investigations showed that such type of semiconductor nanostructures act as efficient working electrodes for the splitting of normal water in PEC method. An enhancement in the photon-to-current conversion efficiency and solar-to-hydrogen evolution was observed for obtaining a practical source of clean and renewable fuel.

  4. Novel application of the CORAL software to model cytotoxicity of metal oxide nanoparticles to bacteria Escherichia coli.

    PubMed

    Toropov, Andrey A; Toropova, Alla P; Benfenati, Emilio; Gini, Giuseppina; Puzyn, Tomasz; Leszczynska, Danuta; Leszczynski, Jerzy

    2012-11-01

    Convenient to apply and available on the Internet software CORAL (http://www.insilico.eu/CORAL) has been used to build up quantitative structure-activity relationships (QSAR) for prediction of cytotoxicity of metal oxide nanoparticles to bacteria Escherichia coli (minus logarithm of concentration for 50% effect pEC50). In this study six random splits of the data into the training and test set were examined. It has been shown that the CORAL provides a reliable tool that could be used to build up a QSAR of the pEC50. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Exposure of WO3 Photoanodes to Ultraviolet Light Enhances Photoelectrochemical Water Oxidation.

    PubMed

    Li, Tengfei; He, Jingfu; Peña, Bruno; Berlinguette, Curtis P

    2016-09-28

    Exposure of WO3 photoanodes to sustained irradiation by ultraviolet (UV) light induces a morphology change that enhances the photoelectrochemical (PEC) activity towards the oxygen evolution reaction (OER). A 30% enhancement in photocurrent density at 1.23 V vs RHE was measured despite a nominal change in onset potential. A structural and electrochemical analysis of the films before and after exposure to UV irradiation indicates that a higher film porosity and correspondingly higher specific surface area is responsible for the enhancement in PEC activity. The effect of prolonged UV irradiation on the WO3 films is fundamentally different to that which was previously observed for BiVO4 films.

  6. Estimation of the Ionosphere and Plasmasphere Contribution to the GPS TEC under Solar Minimum Conditions

    NASA Astrophysics Data System (ADS)

    Zakharenkova, Irina; Cherniak, Iurii; Krankowski, Andrzej; Shagimuratov, Irk; Sieradzki, Rafal

    2012-07-01

    The plasmaspheric electron content (PEC) was estimated by comparison GPS observations and FORMOSAT-3/COSMIC radio occultation (RO) measurements at the extended solar minimum of cycle 23/24. GPS observations provide information about values of vertical total electron content (TEC) up to the metricconverterProductID20,200 km20,200 km. FORMOSAT-3/COSMIC now provides unprecedented global coverage of GPS RO measurements. Depending on the state of the constellation, COSMIC has been producing 1,500 -- 2,500 good soundings of the ionosphere and atmosphere per day, uniformly distributed around the globe. This number of RO is much higher than even before. In this study, COSMIC RO data for different seasons corresponded to equinoxes and solstices of 2007-2009 (March, June, September and December) were analyzed. All selected COSMIC RO electron density profiles were integrated up to the height of metricconverterProductID700 km700 km (altitude of COSMIC satellites), in that way the estimates of ionospheric electron content (IEC) were retrieved on a global scale. The final IGS combined global ionospheric maps (GIMs) were used to calculate the global maps of monthly medians of TEC values. As a result there were analyzed global distributions of GPS TEC and IEC estimates corresponded to the monthly median values for different seasons of 2007-2009. We consider the quantitative differences PEC = TEC -- IEC as a measure of the contribution of the PEC to GPS TEC. In order to analyze seasonal behaviour of PEC contribution to GPS TEC at the different regions we selected several specific points with coordinates, corresponded to the approximate positions of different, mid-latitude and low-latitude, ionospheric sounding stations. Such points were selected at Northern America, European and Asian regions, Southern America, Southern Africa and country-regionplaceAustralia. For each specific points GPS TEC, COSMIC IEC and PEC estimates were analyzed. Results of our comparative study revealed

  7. Use of ground-based and LEO GPS measurements to study the system of the ionosphere/plasmasphere

    NASA Astrophysics Data System (ADS)

    Krankowski, A.; Zakharenkova, I.; Cherniak, I.

    2012-12-01

    The plasmaspheric electron content (PEC) was estimated by comparison GPS observations and FORMOSAT-3/COSMIC radio occultation (RO) measurements at the extended solar minimum of cycle 23/24. GPS observations provide information about values of vertical total electron content (TEC) up to the metricconverterProductID20,200 km20,200 km. FORMOSAT-3/COSMIC now provides unprecedented global coverage of GPS RO measurements. Depending on the state of the constellation, COSMIC has been producing 1,500 - 2,500 good soundings of the ionosphere and atmosphere per day, uniformly distributed around the globe. This number of RO is much higher than even before. In this study, COSMIC RO data for different seasons corresponded to equinoxes and solstices of 2007-2009 (March, June, September and December) were analyzed. All selected COSMIC RO electron density profiles were integrated up to the height of metricconverterProductID700 km700 km (altitude of COSMIC satellites), in thatway the estimates of ionospheric electron content (IEC) were retrieved on a global scale. The final IGS combined global ionospheric maps (GIMs) were used to calculate the global maps of monthly medians of TEC values. As a result there were analyzed global distributions of GPS TEC and IEC estimates corresponded to the monthly median values for different seasons of 2007-2009. We consider the quantitative differences PEC = TEC - IEC as a measure of the contribution of the PEC to GPS TEC. In order to analyze seasonal behaviour of PEC contributionto GPS TEC at the different regions we selected several specific points with coordinates, corresponded to the approximate positions of different, mid-latitude and low-latitude, ionospheric sounding stations. Such points were selected at Northern America, European and Asian regions, Southern America, Southern Africa and country-region place Australia. For each specific points GPS TEC, COSMIC IEC and PEC estimates were analyzed. Results of our comparative study revealed that

  8. Design and Characterization of Photoelectrodes from First Principles

    SciTech Connect

    Ogitsu, T; Wood, B; Choi, W; Huda, M; Wei, S

    2012-05-11

    Although significant performance improvements have been realized since the first demonstration of sunlight-driven water splitting in 1972, mainstream adoption of photoelectrochemical (PEC) cells remains limited by an absence of cost-effective electrodes that show simultaneously high conversion efficiency and good durability. Here we outline current and future efforts to use advanced theoretical techniques to guide the development of a durable, high-performance PEC electrode material. Working in close collaboration with experimental synthesis and characterization teams, we use a twofold approach focusing on: (1) rational design of novel high-performance electrode materials; and (2) characterization and optimization of the electrode-electrolyte interface.

  9. Thoracic interfascial nerve block for breast surgery in a pregnant woman: a case report

    PubMed Central

    Yoon, Seok-Hwa; Kim, Bum June; Song, Seunghyun; Yoon, Yeomyung

    2017-01-01

    Regional anesthesia for non-obstetric surgery in parturients is a method to decrease patient and fetal risk during general anesthesia. Thoracic interfascial nerve block can be used as an analgesic technique for surgical procedures of the thorax. The Pecs II block is an interfascial block that targets not only the medial and lateral pectoral nerves, but also the lateral cutaneous branch of the intercostal nerve. Pecto-intercostal fascial block (PIFB) targets the anterior cutaneous branch of the intercostal nerve. The authors successfully performed a modified Pecs II block and PIFB without complications in a parturient who refused general anesthesia for breast surgery. PMID:28367293

  10. Research Update: Strategies for efficient photoelectrochemical water splitting using metal oxide photoanodes

    SciTech Connect

    Cho, Seungho; Jang, Ji-Wook; Lee, Kun-Hong E-mail: ce20047@postech.ac.kr; Lee, Jae Sung E-mail: ce20047@postech.ac.kr

    2014-01-01

    Photoelectrochemical (PEC) water splitting to hydrogen is an attractive method for capturing and storing the solar energy in the form of chemical energy. Metal oxides are promising photoanode materials due to their low-cost synthetic routes and higher stability than other semiconductors. In this paper, we provide an overview of recent efforts to improve PEC efficiencies via applying a variety of fabrication strategies to metal oxide photoanodes including (i) size and morphology-control, (ii) metal oxide heterostructuring, (iii) dopant incorporation, (iv) attachments of quantum dots as sensitizer, (v) attachments of plasmonic metal nanoparticles, and (vi) co-catalyst coupling. Each strategy highlights the underlying principles and mechanisms for the performance enhancements.

  11. An evaluation of multiple-schedule variations to reduce high-rate requests in the picture exchange communication system.

    PubMed

    Landa, Robin; Hanley, Gregory P

    2016-06-01

    Using procedures similar to those of Tiger, Hanley, and Heal (2006), we compared two multiple-schedule variations (S+/S- and S+ only) to treat high-rate requests for edible items in the Picture Exchange Communication System (PECS). Two individuals with autism participated, after they showed persistent requests for edible items after PECS training. Stimulus control was achieved only with the multiple schedule that involved presentation of a discriminative stimulus during reinforcement components and its removal during extinction components (S+ only). Discriminated requests were maintained for the 1 participant who experienced schedule thinning. © 2016 Society for the Experimental Analysis of Behavior.

  12. Magnetically controllable circulator based on photonic crystal unidirectional waveguide consisting of metamaterials

    NASA Astrophysics Data System (ADS)

    Liang, Wenyao

    2016-09-01

    Unidirectional edge modes are achieved in gyromagnetic photonic crystals. The physical reason is attributed to magnetic resonance and broken time-reversal symmetry under external magnetic fields. These edge modes propagate only along a single direction, while the backward modes are completely suppressed. The unidirectional transmittance is nearly 100% and hardly affected by perfect electric conductor (PEC) defect. However, a PEC defect has sensitive influence on both the phase delay and pattern distribution of unidirectional edge modes. These properties hold promise in designing various unidirectional devices. Here we design a three port circulator with high transmission contrast and magnetic controllability simultaneously.

  13. ZnO Nanocoral Structures for Photoelectrochemical Cells

    SciTech Connect

    Ahn, K. S.; Yan, Y.; Shet, S.; Jones, K.; Deutsch, T.; Turner, J.; Al-Jassim, M.

    2008-01-01

    We report on synthesis of a uniform and large area of a new form of ZnO nanocorals. These nanostructures can provide suitable electrical pathways for efficient carrier collection as well as large surface areas for the photoelectrochemical (PEC) cells. PEC devices made from these ZnO nanocoral structures demonstrate significantly enhanced photoresponse as compared to ZnO compact and nanorod films. Our results suggest that the nanocoral structures could be an excellent choice for nanomaterial-based applications such as dye-sensitized solar cells, electrochromic windows, and batteries.

  14. A series of BCN nanosheets with enhanced photoelectrochemical performances

    NASA Astrophysics Data System (ADS)

    Li, Junqi; Lei, Nan; Hao, Hongjuan; Zhou, Jian

    2017-03-01

    A series of flake-like BCN compounds were produced by calcination at different reaction temperatures via thermal substitution of C atoms with B atoms of boric acid substructures in graphitic carbon nitrides (g-C3N4). The structural and optical properties of the samples were characterized by XRD, TEM, HRTEM, XPS and UV-vis absorption. The photoelectrochemical (PEC) performance of all samples were characterized through photocurrent and electrochemical impedance spectroscopy (EIS) measurement. The test results demonstrated that BCN nanosheets exhibited higher PEC performance with increasing substituted amount of boron.

  15. Ultrasound-Guided Serratus Anterior Plane Block in Breast Reconstruction Surgery.

    PubMed

    Khemka, Rakhi; Chakraborty, Arunangshu; Ahmed, Rosina; Datta, Taniya; Agarwal, Sanjit

    2016-05-01

    Pecs block and its variations have been used for various breast surgeries. We describe 2 cases of mastectomy and breast reconstruction by latissimus dorsi (LD) flap where regional analgesia was provided by a combination of ultrasound-guided Pecs-I block and serratus anterior plane block, a recently described technique in which local anesthetic is deposited in the plane between the LD and serratus anterior muscle. This resulted in excellent intraoperative and postoperative analgesia and a minimum of systemic analgesics. The described technique is safe to administer and provides good analgesia for breast reconstruction surgery by LD flap.

  16. Photoelectrochemical etching of n-InP producing antireflecting structures for solar cells

    NASA Astrophysics Data System (ADS)

    Soltz, David; Cescato, Lucila H. D.; Decker, Franco

    1991-12-01

    Photoelectrochemical (PEC) etching of n-InP is studied as a method to engrave relief microstructures. Experiments of PEC were performed with holographic exposures ((lambda) equals 0.4579 micrometers ) and homogeneous white light on n-InP. The triangular profile characteristic of holographic patterns recorded parallel to the <011> direction appeared even when the sample was etched using homogeneous white light. In this case deep random microstructures were obtained that present interesting anti-reflecting properties that may be useful in solar cells applications.

  17. Polyelectrolyte complexes based on (quaternized) poly[(2-dimethylamino)ethyl methacrylate]: behavior in contact with blood.

    PubMed

    Yancheva, Elena; Paneva, Dilyana; Danchev, Dobri; Mespouille, Laetitia; Dubois, Philippe; Manolova, Nevena; Rashkov, Iliya

    2007-07-09

    Polyelectrolyte complexes (PECs) between (quaternized) poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA) and (crosslinked) N-carboxyethylchitosan (CECh) or poly(2-acrylamido-2-methylpropane sodium sulfonate) (PAMPSNa) were prepared and characterized in terms of their stability, equilibrium water content, and surface morphology. The evaluation of the behavior of the studied PECs in contact with blood revealed that the (crosslinked) CECh/(quaternized) PDMAEMA complexes had lost the inherent PDMAEMA cytotoxicity but still preserved haemostatic activity. In contrast, the complex formation between (quaternized) PDMAEMA and PAMPSNa allowed the preparation of materials with improved blood compatibility.

  18. A Simple Photoelectrochemical Cell Using Fe+++/Fe++(aq) As Redox Couple

    NASA Astrophysics Data System (ADS)

    Saxena, Vibha; Koiry, S. P.; Veerender, P.; Vasundhara, Aswal, D. K.; Gupta, S. K.; Shivran, Neelam; Mula, S.; Chattopadhyay, S.; Yakhmi, J. V.

    2010-12-01

    We report a simple photoelectrochemical cell (PEC) using a derivative of borondipyrromethane (BODIPY), that is, (4,4-difluoro-1,3,5,7,8-pentamethyl-2,6-diethyl-4-bora-3a,4a-diaza-s-indecene) as dye sensitizer and an aqueous electrolyte containing Ferric/ferrous redox couple (F+++/Fe++). Under white light illumination of intensity ˜1 mW/cm2, the open circuit voltage and short-circuit current of the PEC was found to be respectively, 180 mV and 1.3 μA/cm2.

  19. Transgastric long tube placement following percutaneous endoscopic gastrostomy for severe chronic intestinal pseudo-obstruction related to systemic sclerosis.

    PubMed

    Nunokawa, Takahiro; Yokogawa, Naoto; Ohtsuka, Hideo; Shimada, Kota; Sugii, Shoji

    2015-01-01

    Medical management of systemic sclerosis (SSc)-associated chronic intestinal pseudo- obstruction (CIPO) has often proved inadequate. Percutaneous endoscopic colostomy (PEC) has been proposed as a method of treatment, but it is associated with a relatively high incidence of serious complications. We report herein a very severe case of SSc-associated CIPO in which complications were successfully controlled by long tube placement via a gastrostomy. Transgastric long tube placement may offer a relatively safe alternative to PEC in treating severe SSc-associated CIPO.

  20. A THEORETICAL STUDY OF BISTABILITY OF POLYDIACETYLENE:. TCDU(poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)

    NASA Astrophysics Data System (ADS)

    Katagiri, Hideki; Shimoi, Yukihiro; Abe, Shuji

    2001-08-01

    We performed a first-principles calculation of typical polydiacetylene (PDA), TCDU (poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)). Potential energy curves (PEC's) as a function of two bond lengths of the backbone chain are presented. The present PEC's show that TCDU has only an acetylene-type stable structure and a butatriene-type structure is unstable, consistent with our previous calculations with a geometry optimization procedure. This result is in contrast to the case of a hypothetical hydrogen-substituted PDA where a butatriene-type structure is obtained as a meta-stable structure.

  1. A THEORETICAL STUDY OF BISTABILITY OF POLYDIACETYLENE:. TCDU(poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)

    NASA Astrophysics Data System (ADS)

    Katagiri, Hideki; Shimoi, Yukihiro; Abe, Shuji

    We performed a first-principles calculation of typical polydiacetylene (PDA), TCDU (poly(5,7-dodecadiyne-1,12-diyl-bis-phenylurethane)). Potential energy curves (PEC's) as a function of two bond lengths of the backbone chain are presented. The present PEC's show that TCDU has only an acetylene-type stable structure and a butatriene-type structure is unstable, consistent with our previous calculations with a geometry optimization procedure. This result is in contrast to the case of a hypothetical hydrogen-substituted PDA where a butatriene-type structure is obtained as a meta-stable structure.

  2. Examination of biogenic selenium-containing nanosystems based on polyelectrolyte complexes by atomic force, Kelvin probe force and electron microscopy methods

    SciTech Connect

    Sukhanova, T. E. Vylegzhanina, M. E.; Valueva, S. V.; Volkov, A. Ya.; Kutin, A. A.; Temiryazeva, M. P.; Temiryazev, A. G.

    2016-06-17

    The morphology and electrical properties of biogenic selenium-containing nanosystems based on polyelectrolyte complexes (PECs) were examined using AFM, Kelvin Probe Force and electron microscopy methods. It has been found, that prepared nanostructures significantly differed in their morphological types and parameters. In particular, multilayers capsules can be produced via varying synthesis conditions, especially, the selenium–PEC mass ratio ν. At the “special point” (ν = 0.1), filled and hollow nano- and microcapsules are formed in the system. The multilayer character of the capsules walls is visible in the phase images. Kelvin Probe Force images showed the inhomogeneity of potential distribution in capsules and outside them.

  3. Exciton-plasmon interactions between CdS quantum dots and Ag nanoparticles in photoelectrochemical system and its biosensing application.

    PubMed

    Zhao, Wei-Wei; Yu, Pei-Pei; Shan, Yun; Wang, Jing; Xu, Jing-Juan; Chen, Hong-Yuan

    2012-07-17

    With DNA as a rigid spacer, Ag nanoparticles (NPs) were bridged to CdS quantum dots (QDs) for the stimulation of exciton-plasmon interactions (EPI) in a photoelectrochemical (PEC) system. Due to their natural absorption overlap, the exciton of the QDs and the plasmon of Ag NPs could be induced simultaneously. The EPI resonant nature enabled manipulating photoresponse of the QDs via tuning interparticle distances. Specifically, the photocurrent of the QDs could be greatly attenuated and even be completely damped by the generated EPI. The work opens a different horizon for EPI investigation through an engineered PEC nanosystem, and provides a viable mechanism for new DNA sensing protocol.

  4. Silicon nanostructures-induced photoelectrochemical solar water splitting for energy applications

    NASA Astrophysics Data System (ADS)

    Dadwal, U.; Ranjan, Neha; Singh, R.

    2016-05-01

    We study the photoelectrochemical (PEC) solar water splitting assisted with synthesized nanostructures. Si nanowires decorated with silver dendrite nanostructures have been synthesized using metal assisted wet chemical etching of (100) Si wafer. Etching has been carried out in an aqueous solution consisting of 5M HF and 0.02M AgNO3. Investigations showed that such type of semiconductor nanostructures act as efficient working electrodes for the splitting of normal water in PEC method. An enhancement in the photon-to-current conversion efficiency and solar-to-hydrogen evolution was observed for obtaining a practical source of clean and renewable fuel.

  5. PehN, a polygalacturonase homologue with a low hydrolase activity, is coregulated with the other Erwinia chrysanthemi polygalacturonases.

    PubMed

    Hugouvieux-Cotte-Pattat, Nicole; Shevchik, Vladimir E; Nasser, William

    2002-05-01

    Erwinia chrysanthemi 3937 secretes an arsenal of pectinolytic enzymes, including at least eight endo-pectate lyases encoded by pel genes, which play a major role in the soft-rot disease caused by this bacterium on various plants. E. chrysanthemi also produces some hydrolases that cleave pectin. Three adjacent hydrolase genes, pehV, pehW, and pehX, encoding exo-poly-alpha-D-galacturonosidases, have been characterized. These enzymes liberate digalacturonides from the nonreducing end of pectin. We report the identification of a novel gene, named pehN, encoding a protein homologous to the glycosyl hydrolases of family 28, which includes mainly polygalacturonases. PehN has a low hydrolase activity on polygalacturonate and on various pectins. PehN action favors the activity of the secreted endo-pectate lyases, mainly PelB and PelC, and that of the periplasmic exo-pectate lyase PelX. However, removal of the pehN gene does not significantly alter the virulence of E. chrysanthemi. Regulation of pehN transcription was analyzed by using gene fusions. Like other pectinase genes, pehN transcription is dependent on several environmental conditions. It is induced by pectic catabolic products and is affected by growth phase, catabolite repression, osmolarity, anaerobiosis, nitrogen starvation, and the presence of calcium ions. The transcription of pehN is modulated by the repressor KdgR, which controls almost all the steps of pectin catabolism, and by cyclic AMP receptor protein (CRP), the global activator of sugar catabolism. The regulator PecS, which represses the transcription of the pel genes but activates that of pehV, pehW, and pehX, also activates transcription of pehN. The three regulators KdgR, PecS, and CRP act by direct interaction with the pehN promoter region. The sequences involved in the binding of these three regulators and of RNA polymerase have been precisely defined. Analysis of the simultaneous binding of these proteins indicates that CRP and RNA polymerase

  6. Constructing Fe2O3/TiO2 core-shell photoelectrodes for efficient photoelectrochemical water splitting

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Pyeon, Myeongwhun; Gönüllü, Yakup; Kaouk, Ali; Shen, Shaohua; Guo, Liejin; Mathur, Sanjay

    2015-05-01

    In this study, plasma enhanced chemical vapor deposition (PECVD) was utilized to co-axially modify hydrothermally grown Fe2O3 nanorod arrays by depositing a TiO2 overlayer to create Fe2O3/TiO2 core-shell photoelectrodes. Comprehensive structural (XRD, SEM, TEM) and compositional (XPS) analyses were performed to understand the effects of the TiO2 shell on the PEC activities of the Fe2O3 core. It was revealed that the heterojunction structure formed between TiO2 and Fe2O3, significantly improved the separation efficiency of photo-induced charge carriers and the oxygen evolution kinetics. A maximum photocurrent density of ~900 μA cm-2 at 0.6 V vs. saturated calomel electrode (SCE) was obtained for the Fe2O3/TiO2 photoelectrodes, which was 5 and 18 times higher when compared to that of hydrothermally synthesized Fe2O3 and PECVD synthesized TiO2 electrodes, respectively. Moreover, the Fe2O3/TiO2 core-shell nanorod arrays displayed superior stability for PEC water splitting. During 5000 s PEC measurements, a steady decrease of the photocurrent was observed, mainly attributed to the evolution of oxygen bubbles adsorbed on the working electrodes. This observation was verified by the complete recovery of the PEC performance demonstrated for a second 5000 s PEC measurement carried out after a brief time interval (10 min) that allowed the electrode surface to regenerate.In this study, plasma enhanced chemical vapor deposition (PECVD) was utilized to co-axially modify hydrothermally grown Fe2O3 nanorod arrays by depositing a TiO2 overlayer to create Fe2O3/TiO2 core-shell photoelectrodes. Comprehensive structural (XRD, SEM, TEM) and compositional (XPS) analyses were performed to understand the effects of the TiO2 shell on the PEC activities of the Fe2O3 core. It was revealed that the heterojunction structure formed between TiO2 and Fe2O3, significantly improved the separation efficiency of photo-induced charge carriers and the oxygen evolution kinetics. A maximum photocurrent

  7. Consolidation of materials by pulse-discharge processes

    NASA Astrophysics Data System (ADS)

    Strizhakov, E. L.; Nescoromniy, S. V.

    2017-07-01

    The article presents the research and the analysis of the pulse-discharge processes of capacitor discharge sintering: CD Stud Welding, capacitor discharge percussion welding (CDPW), high-voltage capacitor welding with an inductive-dynamic drive (HVCW with IDD), pulse electric current sintering (PECS) of powders. The comparative analysis of the impact parameter is presented.

  8. The phenotypes of podocytes and parietal epithelial cells may overlap in diabetic nephropathy

    PubMed Central

    Andeen, Nicole K.; Nguyen, Tri Q.; Steegh, Floor; Hudkins, Kelly L.; Najafian, Behzad; Alpers, Charles E.

    2015-01-01

    Reversal of diabetic nephropathy (DN) has been achieved in humans and mice, but only rarely and under special circumstances. Since progression of DN is related to podocyte loss, reversal of DN requires restoration of podocytes. Here we identified and quantified potential glomerular progenitor cells that could be a source for restored podocytes. DN was identified in 31 human renal biopsy cases and separated into morphologically early or advanced lesions. Markers of podocytes (WT-1, p57), parietal epithelial cells (claudin-1) and cell proliferation (Ki-67) were identified by immunohistochemistry. Podocyte density was progressively reduced with DN. Cells marking as podocytes (p57) were present infrequently on Bowman's capsule in controls, but significantly increased in histologically early DN. Ki-67 expressing cells were identified on the glomerular tuft and Bowman's capsule in DN, but rarely in controls. Cells marking as PECs were present on the glomerular tuft, particularly in morphologically advanced DN. These findings show evidence of phenotypic plasticity in podocyte and PEC populations and are consistent with studies in the BTBR ob/ob murine model in which reversibility of DN occurs with podocytes potentially regenerating from PEC precursors. Thus, our findings support, but do not prove, that podocytes may regenerate from PEC progenitors in human DN. If so, progression of DN may represent a modifiable net balance between podocyte loss and regeneration. PMID:26376129

  9. New nasal nanocomplex self-assembled from charged biomacromolecules: N,N,N-Trimethyl chitosan and dextran sulfate.

    PubMed

    Kulkarni, Abhijeet D; Vanjari, Yogesh H; Sancheti, Karan H; Patel, Harun M; Belgamwar, Veena S; Surana, Sanjay J; Pardeshi, Chandrakantsing V

    2016-07-01

    Although chitosan (CHT, a linear cationic polysaccharide) is biodegradable, biocompatible, non-toxic, and mucoadhesive in nature, the low solubility of CHT in aqueous and alkaline media limits its applicability in pharmaceutical and biomedical field. This necessitate the introduction of new chemically-modified derivatives of CHT those can surmount the solubility barrier. Herein, N,N,N-trimethyl chitosan (TMC), a quaternized hydrophilic derivative of CHT, was synthesized by two-step reductive methylation of CHT and characterized for (1)H NMR and zeta potential measurements. Polyelectrolyte complexes (PECs) based on TMC and dextran sulfate (DS) were prepared via ionic interactions between charged functional groups of former polysaccharides at different pH conditions (pH 5, 8, 10, and 12) and characterized for physicochemical (particle size and zeta potential) and solid- state characterizations (HR-TEM, SEM, FTIR, TGA and XRD). At alkaline pH conditions, the participant polymer chains (TMC and DS) are sufficiently close to form more stable PECs. The release efficiency was assessed after loading a model drug into optimized PEC formulation. Data indicated that the PECs fabricated at alkaline pH presents a reliable formulation for pharmaceutical and biomedical applications.

  10. Thin-film photovoltaic cells: long-term metal(loid) leaching at their end-of-life.

    PubMed

    Zimmermann, Yannick-Serge; Schäffer, Andreas; Corvini, Philippe F-X; Lenz, Markus

    2013-11-19

    The photovoltaic effect of thin-film copper indium gallium selenide cells (CIGS) is conferred by the latter elements. Organic photovoltaic cells (OPV), relying on organic light-absorbing molecules, also contain a variety of metals (e.g., Zn, Al, In, Sn, Ag). The environmental impact of such technologies is largely unknown, in particular when the physical integrity deteriorates upon end-of-life, possibly facilitating cell constituent leaching. This study analyzed long-term inorganic leaching from damaged OPV and CIGS into different model waters. Leachate concentrations were put into perspective by calculating the predicted environmental concentrations (PEC) for several scenarios. Roof-top acidic rain runoff from CIGS was found to be the predominant emission source for metals and metalloids, with Cd released to such extents that PEC (173.4 μg Cd L(-1)) would considerably exceed acute toxicity concentrations for Daphnia magna . Other PEC for CIGS (9.9 mg Mo L(-1) and 9.4 μg Se L(-1)) were in the range of teratogenic effects. In contrast, OPV released little metals with calculated PEC being below even conservative drinking water guidelines. Time-resolved single-particle ICP-MS indicated that some metals (Zn, Mo, Ag) were in nanoparticulate form, raising nanotoxicity concerns. Leaching kinetics called for revision of existing standardized (accelerated) leaching protocols because long-term release was most relevant.

  11. A Further Evaluation of Behavioral Skills Training for Implementation of the Picture Exchange Communication System

    ERIC Educational Resources Information Center

    Homlitas, Christa; Rosales, Rocío; Candel, Lindsay

    2014-01-01

    We evaluated the effectiveness of a behavioral skills training package to teach implementation of Phases 1, 2, and 3A of the picture exchange communication system (PECS) to teachers employed at a therapeutic center for children with autism. Probes in the natural environment and follow-up were conducted with children who were assigned to work with…

  12. Metagenomics and the poultry gut: using the next generation of nucleic acid sequencing to identify enteric viruses

    USDA-ARS?s Scientific Manuscript database

    Enteric disease syndromes such as Poult Enteritis Complex (PEC) in young turkeys and Runting-Stunting Syndrome (RSS) in chickens are a continual economic burden for poultry producers. The only reliable method to reproduce these syndromes in experimental birds is oral inoculation with crude preparat...

  13. Hydrogen plasma reduced black TiO2sbnd B nanowires for enhanced photoelectrochemical water-splitting

    NASA Astrophysics Data System (ADS)

    Tian, Zhangliu; Cui, Huolei; Zhu, Guilian; Zhao, Wenli; Xu, JiJian; Shao, Feng; He, Jianqiao; Huang, Fuqiang

    2016-09-01

    Black TiO2 with various nanostructures and phase constitutions have been reported to exhibit excellent photocatalytic and photoelectrochemical (PEC) performance. Here, we report the fabrication of black nanostructured TiO2sbnd B through hydrogen plasma assisted reduction and its enhanced PEC properties for the first time. Both the obtained TiO2sbnd B and black TiO2sbnd B are single crystalline nanowires, while the black TiO2sbnd B samples exhibit much stronger visible and infrared light absorption. The optimal black TiO2sbnd B sample obtained by hydrogen plasma treatment at 425 °C yields a photocurrent density of 0.85 mA cm-2, a rather low onset potential of -0.937 VAg/AgCl and a high applied bias photon-to-current efficiency (ABPE) of 0.363%, which is far superior to the TiO2sbnd B (0.15 mA cm-2 photocurrent, -0.917 VAg/AgCl onset potential and 0.138% ABPE). The significantly enhanced PEC performance of the black TiO2sbnd B is ascribed to the introduction of moderate surface oxygen vacancies. These results indicate that the black TiO2sbnd B is a promising material for PEC application and solar energy utilization.

  14. Ultrasensitive photoelectrochemical determination of chromium(VI) in water samples by ion-imprinted/formate anion-incorporated graphitic carbon nitride nanostructured hybrid.

    PubMed

    Fang, Tian; Yang, Xiaomin; Zhang, Lizhi; Gong, Jingming

    2016-07-15

    A rapid and highly sensitive photoelectrochemical (PEC) method has been proposed for the determination of trace amounts of chromium in water samples under visible-light irradiation. Here, a unique nanostructured hybrid of formate anion incorporated graphitic carbon nitride (F-g-C3N4) is smartly integrated with a Cr(VI) ion-imprinted polymer (IIP) as a photoactive electrode (denoted as IIP@F-g-C3N4). The nanohybrid of F-g-C3N4 exhibits an enhanced charge separation with substantially improved PEC responses versus g-C3N4. The newly designed IIP@F-g-C3N4 PEC sensor exhibits high sensitivity and selectivity for the determination of Cr(VI) because it offers efficient photogenerated electron reduction toward Cr(VI). The PEC analysis is highly linear over Cr(VI) concentrations ranging from 0.01 to 100.00ppb with a detection limit of 0.006ppb (S/N=3). Our approach can be used to detect Cr(VI), Cr(III) and the total chromium level in aqueous solution through oxidation of Cr(III) to Cr(VI) and the determination of the total chromium as Cr(VI). In practical applications, this low-cost and sensitive assay has been successfully applied for speciation determination of chromium in environmental water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Comparative metagenomic analyses of the poultry enteric virome: implications for diagnostics

    USDA-ARS?s Scientific Manuscript database

    Previous comparative metagenomic analyses of the viral communities present in the poultry gut have revealed novel enteric viruses that may affect the overall performance of birds or that may play roles in disease syndromes such as Runting-Stunting Syndrome (RSS) or Poult Enteritis Complex (PEC). Ou...

  16. A generalization of CAPE into potential-energy convertibility

    NASA Astrophysics Data System (ADS)

    Yano, Jun-Ichi; Chaboureau, Jean-Pierre; Guichard, Françoise

    2005-04-01

    The concept of the potential-energy convertibility (PEC) is proposed as a generalization of convective available potential energy (CAPE). It is defined as a vertical integral of buoyancy weighted by a non-dimensional normalized vertical momentum. This is a measure of convertibility of potential energy into kinetic energy in the sense that the actual conversion rate is recovered when PEC evaluated by the convective-scale local buoyancy and vertical momentum, as available from cloud-resolving model (CRM) simulations, is multiplied by the normalization factor for the vertical momentum. It reduces to CAPE, when the standard parcel-lifted buoyancy and a unit value for the normalized vertical momentum are used. It is equivalent to Arakawas-Schubert's cloud work function, when the buoyancy and the vertical momentum profile for an entraining plume are used. PEC evaluated from locally defined buoyancy and vertical momentum in CRM simulations correlates better with the convective precipitation than CAPE. The evaluation of PEC within a convective parametrization may be possible with an appropriate definition of the effective entrainment rate, for example, which is expected to improve CAPE-based convective parametrizations.

  17. Model to Test Electric Field Comparisons in a Composite Fairing Cavity

    NASA Technical Reports Server (NTRS)

    Trout, Dawn H.; Burford, Janessa

    2013-01-01

    Evaluating the impact of radio frequency transmission in vehicle fairings is important to sensitive spacecraft. This study shows cumulative distribution function (CDF) comparisons of composite a fairing electromagnetic field data obtained by computational electromagnetic 3D full wave modeling and laboratory testing. This work is an extension of the bare aluminum fairing perfect electric conductor (PEC) model. Test and model data correlation is shown.

  18. Model to Test Electric Field Comparisons in a Composite Fairing Cavity

    NASA Technical Reports Server (NTRS)

    Trout, Dawn; Burford, Janessa

    2012-01-01

    Evaluating the impact of radio frequency transmission in vehicle fairings is important to sensitive spacecraft. This study shows cumulative distribution function (CDF) comparisons of composite . a fairing electromagnetic field data obtained by computational electromagnetic 3D full wave modeling and laboratory testing. This work is an extension of the bare aluminum fairing perfect electric conductor (PEC) model. Test and model data correlation is shown.

  19. Uniform Doping of Titanium in Hematite Nanorods for Efficient Photoelectrochemical Water Splitting.

    PubMed

    Wang, Degao; Chen, Huaican; Chang, Guoliang; Lin, Xiao; Zhang, Yuying; Aldalbahi, Ali; Peng, Cheng; Wang, Jianqiang; Fan, Chunhai

    2015-07-01

    Doping elements in hematite nanostructures is a promising approach to improve the photoelectrochemical (PEC) water-splitting performance of hematite photoanodes. However, uniform doping with precise control on doping amount and morphology is the major challenge for quantitatively investigating the PEC water-splitting enhancement. Here, we report on the design and synthesis of uniform titanium (Ti)-doped hematite nanorods with precise control of the Ti amount and morphology for highly effective PEC water splitting using an atomic layer deposition assisted solid-state diffusion method. We found that Ti doping promoted band bending and increased the carrier density as well as the surface state. Remarkably, these uniformly doped hematite nanorods exhibited high PEC performance with a pronounced photocurrent density of 2.28 mA/cm(2) at 1.23 V vs reversible hydrogen electrode (RHE) and 4.18 mA/cm(2) at 1.70 V vs RHE, respectively. Furthermore, as-prepared Ti-doping hematite nanorods performed excellent repeatability and durability; over 80% of the as-fabricated photoanodes reproduced the steady photocurrent density of 1.9-2.2 mA/cm(2) at 1.23 V vs RHE at least 3 h in a strong alkaline electrolyte solution.

  20. Photoanodes based on TiO2 and α-Fe2O3 for solar water splitting - superior role of 1D nanoarchitectures and of combined heterostructures.

    PubMed

    Kment, Stepan; Riboni, Francesca; Pausova, Sarka; Wang, Lei; Wang, Lingyun; Han, Hyungkyu; Hubicka, Zdenek; Krysa, Josef; Schmuki, Patrik; Zboril, Radek

    2017-06-19

    Solar driven photoelectrochemical water splitting (PEC-WS) using semiconductor photoelectrodes represents a promising approach for a sustainable and environmentally friendly production of renewable energy vectors and fuel sources, such as dihydrogen (H2). In this context, titanium dioxide (TiO2) and iron oxide (hematite, α-Fe2O3) are among the most investigated candidates as photoanode materials, mainly owing to their resistance to photocorrosion, non-toxicity, natural abundance, and low production cost. Major drawbacks are, however, an inherently low electrical conductivity and a limited hole diffusion length that significantly affect the performance of TiO2 and α-Fe2O3 in PEC devices. To this regard, one-dimensional (1D) nanostructuring is typically applied as it provides several superior features such as a significant enlargement of the material surface area, extended contact between the semiconductor and the electrolyte and, most remarkably, preferential electrical transport that overall suppress charge carrier recombination and improve TiO2 and α-Fe2O3 photoelectrocatalytic properties. The present review describes various synthetic methods and modifying concepts of 1D-photoanodes (nanotubes, nanorods, nanofibers, nanowires) based on titania, hematite, and on α-Fe2O3/TiO2 heterostructures, for PEC applications. Various routes towards modification and enhancement of PEC activity of 1D photoanodes are discussed including doping, decoration with co-catalysts and heterojunction engineering. Finally, the challenges related to the optimization of charge transfer kinetics in both oxides are highlighted.