WorldWideScience

Sample records for factors controlling microbial

  1. Microbial control of pollution

    Energy Technology Data Exchange (ETDEWEB)

    Fry, J C; Gadd, G M; Herbert, R A; Jones, C W; Watson-Craik, I A [eds.

    1992-01-01

    12 papers are presented on the microbial control of pollution. Topics covered include: bioremediation of oil spills; microbial control of heavy metal pollution; pollution control using microorganisms and magnetic separation; degradation of cyanide and nitriles; nitrogen removal from water and waste; and land reclamation and restoration.

  2. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Badawi, N.; Aamand, Jens

    2014-01-01

    across pesticide classes: they include some soil characteristics (pH) and some agricultural management practices (pesticide application, tillage), while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance......Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we...... critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates...

  3. Fine scale spatial variability of microbial pesticide degradation in soil: scales, controlling factors, and implications

    Directory of Open Access Journals (Sweden)

    Arnaud eDechesne

    2014-12-01

    Full Text Available Pesticide biodegradation is a soil microbial function of critical importance for modern agriculture and its environmental impact. While it was once assumed that this activity was homogeneously distributed at the field scale, mounting evidence indicates that this is rarely the case. Here, we critically examine the literature on spatial variability of pesticide biodegradation in agricultural soil. We discuss the motivations, methods, and main findings of the primary literature. We found significant diversity in the approaches used to describe and quantify spatial heterogeneity, which complicates inter-studies comparisons. However, it is clear that the presence and activity of pesticide degraders is often highly spatially variable with coefficients of variation often exceeding 50% and frequently displays nonrandom spatial patterns. A few controlling factors have tentatively been identified across pesticide classes: they include some soil characteristics (pH and some agricultural management practices (pesticide application, tillage, while other potential controlling factors have more conflicting effects depending on the site or the pesticide. Evidence demonstrating the importance of spatial heterogeneity on the fate of pesticides in soil has been difficult to obtain but modelling and experimental systems that do not include soil’s full complexity reveal that this heterogeneity must be considered to improve prediction of pesticide biodegradation rates or of leaching risks. Overall, studying the spatial heterogeneity of pesticide biodegradation is a relatively new field at the interface of agronomy, microbial ecology, and geosciences and a wealth of novel data is being collected from these different disciplinary perspectives. We make suggestions on possible avenues to take full advantage of these investigations for a better understanding and prediction of the fate of pesticides in soil.

  4. New microbial growth factor

    Science.gov (United States)

    Bok, S. H.; Casida, L. E., Jr.

    1977-01-01

    A screening procedure was used to isolate from soil a Penicillium sp., two bacterial isolates, and a Streptomyces sp. that produced a previously unknown microbial growth factor. This factor was an absolute growth requirement for three soil bacteria. The Penicillium sp. and one of the bacteria requiring the factor, an Arthrobacter sp., were selected for more extensive study concerning the production and characteristics of the growth factor. It did not seem to be related to the siderochromes. It was not present in soil extract, rumen fluid, or any other medium component tested. It appears to be a glycoprotein of high molecular weight and has high specific activity. When added to the diets for a meadow-vole mammalian test system, it caused an increased consumption of diet without a concurrent increase in rate of weight gain.

  5. Microbial translocation and cardiometabolic risk factors in HIV infection

    DEFF Research Database (Denmark)

    Trøseid, Marius; Manner, Ingjerd W; Pedersen, Karin K

    2014-01-01

    of microbial translocation are closely associated with several cardiovascular risk factors such as dyslipidemia, insulin resistance, hypertension, coagulation abnormalities, endothelial dysfunction, and carotid atherosclerosis. Future studies should investigate whether associations between microbial...

  6. Control of Pecan Weevil With Microbial Biopesticides.

    Science.gov (United States)

    Shapiro-Ilan, David I; Cottrell, Ted E; Bock, Clive; Mai, Kim; Boykin, Debbie; Wells, Lenny; Hudson, William G; Mizell, Russell F

    2017-12-08

    The pecan weevil, Curculio caryae (Horn) (Coleoptera: Curculionidae), is a key pest of pecans Carya illinoinensis ([Wangenh.] K. Koch) (Fagales: Juglandaceae). Control recommendations rely on broad spectrum chemical insecticides. Due to regulatory and environmental concerns, effective alternatives for C. caryae control must be sought for pecan production in conventional and organic systems. We explored the use of microbial biopesticides for control of C. caryae in Georgia pecan orchards. Three experiments were conducted. The first investigated an integrated microbial control approach in an organic system at two locations. Three microbial agents, Grandevo (based on byproducts of the bacterium Chromobacterium subtsugae Martin, Gundersen-Rindal, Blackburn & Buyer), the entomopathogenic nematode Steinernema carpocapsae (Weiser), and entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin, were applied to each treatment plot (0.6 ha) at different times during the season. A second experiment compared the effects of S. carpocapsae and B. bassiana applied as single treatments relative to application of both agents (at different times); survival of C. caryae was assessed approximately 11 mo after larvae were added to pots sunk in an organic pecan orchard. In a conventional orchard (with 1.0 ha plots), the third experiment compared Grandevo applications to a commonly used regime of chemical insecticides (carbaryl alternated with a pyrethroid). All experiments were repeated in consecutive years. The combined pest management tactic (experiment 1) reduced C. caryae infestation relative to non-treated control plots in both locations in 2014 and one of the two locations in 2015 (the other location had less than 1% infestation). In experiment 2, no differences among combined microbial treatments, single-applied microbial treatments or different numbers of application were observed, yet all microbial treatments reduced C. caryae survival relative to the control. In the third

  7. Engineering microbial consortia for controllable outputs

    Energy Technology Data Exchange (ETDEWEB)

    Lindemann, Stephen R.; Bernstein, Hans C.; Song, Hyun-Seob; Fredrickson, Jim K.; Fields, Matthew W.; Shou, Wenying; Johnson, David R.; Beliaev, Alexander S.

    2016-03-11

    Much research has been invested into engineering microorganisms to perform desired biotransformations; nonetheless, these efforts frequently fall short of expected results due to the unforeseen effects of biofeedback regulation and functional incompatibility. In nature, metabolic function is compartmentalized into diverse organisms assembled into resilient consortia, in which the division of labor is thought to lead to increased community efficiency and productivity. Here, we consider whether and how consortia can be designed to perform bioprocesses of interest beyond the metabolic flexibility limitations of a single organism. Advances in post-genomic analysis of microbial consortia and application of high-resolution global measurements now offer the promise of systems-level understanding of how microbial consortia adapt to changes in environmental variables and inputs of carbon and energy. We argue that when combined with appropriate modeling framework that predictive knowledge generates testable hypotheses and orthogonal synthetic biology tools, such understanding can dramatically improve our ability to control the fate and functioning of consortia. In this article, we articulate our collective perspective on the current and future state of microbial community engineering and control while placing specific emphasis on ecological principles that promote control over community function and emergent properties.

  8. Opportunities for microbial control of pulse crop pests

    Science.gov (United States)

    The insect pest complex in U.S. pulse crops is almost an “orphan” in terms of developed microbial control agents that the grower can use. There are almost no registered microbial pest control agents (MPCA) for the different pulse pests. In some cases a microbial is registered for use against specifi...

  9. Disposable contact lens use as a risk factor for microbial keratitis

    OpenAIRE

    Radford, C.; Minassian, D.; Dart, J.

    1998-01-01

    AIMS—A case-control study was performed to evaluate soft contact lens (SCL) wear modality as a risk factor for microbial keratitis.
METHODS—Contact lens wearers presenting as new patients to Moorfields Eye Hospital accident and emergency department during a 12 month period completed a self administered questionnaire detailing demographic data and contact lens use habits. Cases were patients with a clinical diagnosis of SCL related microbial keratitis. Controls were SCL users attending with di...

  10. Irradiation of microbial controlling on package tofu

    International Nuclear Information System (INIS)

    Gao Meixu; Li Shurong; Wang Li; Wang Shuo; Wang Ning

    2009-01-01

    The effects of irradiation on microbiological controlling, nutrient and sensory qualities of packaged tofu (bean curd) stored at commercial condition. Results showed that D 10 values of Listeria innocua and Samonella enteritidis inoculated in packaged tofu were 0.225 and 0.240kGy, respectively. Irradiation dose lower than 2.0kGy had no significant effects on content of crude protein and amino acid (p>0.05). γ-irradiation could decrease microbial in packaged tofu and 2.0kGy should be applied to ensure the hygienic quality of the products. (authors)

  11. Microbial control of seawater by microfiltration

    Directory of Open Access Journals (Sweden)

    Wilmer Soler T

    2010-08-01

    Full Text Available Recent scientific literature presents seawater as a potential aid to solve a variety of health diseases in animals and human beings because by means of its mineral and trace elements content. In Colombia, Nicaragua and Spain it is collected in a natural way from de shore and drunk; however, this can represent a health risk because of the problems related to chemical and microbiological contamination. Microbial control of seawater allows the improvement of its microbiological quality. Objective: to compare the efficiency of three microbial control methods: microfiltration, solar exposition and quarantine. Methodology: 30 samples were collected in 20-liter high density polyethylene containers in three different places in the Colombian Atlantic coast. Results: 15 samples out of 30 showed the presence of bacteria such as E. coli and halophiles bacteria like Vibrio and Aeromonas. Microfiltration through ceramic filters of 0.5 µm produces disinfection in 100% of the samples but the quarantine for five months and solar disinfection are effective in 66 and 21% respectively. The latter requires certain weather conditions to achieve disinfection and it only allows managing small quantities of water. Dicussion: Considering chemical contamination in some places which cannot be controlled through disinfection methods, the collection of water offshore in clean places is suggested and then microfiltration treatment should be performed.

  12. Factors Affecting Microbial Contamination of Market Eggs: A Review

    Directory of Open Access Journals (Sweden)

    Svobodová J.

    2015-01-01

    Full Text Available The aim of the review was to analyze the ways of microbial contamination, the protective mechanism of egg, and factors that affect the quantity of contamination and microbial penetration. Eggs can be contaminated during their formation in the infected reproductive organs of hens or after laying, when eggs are exposed to contaminated environment. The eggs are equipped against microbial contamination by several protective mechanisms comprising the presence of cuticle, eggshell, eggshell membranes, occurrence of some antibacterial proteins, and high pH value of albumen. There are several factors that affect the quantity of microbial contamination and penetration such as species of bacteria, the amount of microorganisms, storage conditions, quality of eggshell or number of pores.

  13. Augmenting Plant Immune Responses and Biological Control by Microbial Determinants

    Directory of Open Access Journals (Sweden)

    Sang Moo Lee

    2015-09-01

    Full Text Available Plant have developed sophisticated defence mechanisms against microbial pathogens. The recent accumulated information allow us to understand the nature of plant immune responses followed by recognition of microbial factors/determinants through cutting-edge genomics and multi-omics techniques. However, the practical approaches to sustain plant health using enhancement of plant immunity is yet to be fully appreciated. Here, we overviewed the general concept and representative examples on the plant immunity. The fungal, bacterial, and viral determinants that was previously reported as the triggers of plant immune responses are introduced and described as the potential protocol of biological control. Specifically, the role of chitin, glucan, lipopolysaccharides/extracellular polysaccharides, microbe/pathogen-associated molecular pattern, antibiotics, mimic-phytohormones, N-acyl homoserine lactone, harpin, vitamins, and volatile organic compounds are considered. We hope that this review stimulates scientific community and farmers to broaden their knowledge on the microbial determinant-based biological control and to apply the technology on the integrated pest management program.

  14. Do microbial exudates control EH electrode measurements?

    Science.gov (United States)

    Markelova, E.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2017-12-01

    Redox electrodes are widely used as simple, inexpensive monitoring devices to rapidly measure redox potentials (EH) of waterlogged soils, sediments, and aquifers. While a variety of physicochemical and biogeochemical factors have been involved to explain measured EH values, the role of microorganisms remains comparatively understudied and uncertain. Besides catalyzing many inorganic redox reactions (e.g., nitrate reduction), microorganisms produce a variety of redox-active organic compounds (e.g., NAD+/NADH, GSSG/2GSH, FAD/FADH2), which can be released into the surrounding environment via active secretion, passive diffusion, or cell lysis. To isolate different microbial effects on EH measurements, we performed batch experiments using S. oneidensis MR-I as a model heterotrophic microorganism and flavins as example microbial exudates [1]. We monitored EH and pH along with flavin production (fluorescence measurements) during dissimilatory nitrate reduction to ammonium (DNRA). Dissolved flavins increased to 0.2 mM (riboflavin equivalent) under anoxic conditions during complete consumption of 1 mM nitrate by DNRA at pH 7.4 and 30 °C over 80 hours. The observed redox cascade from +255 to -250 mV did not follow the EH predicted for the reduction of NO3- to NO2- and NO2- to NH4+ by the Nernst equation. However, a set of separate abiotic experiments on the photoreduction of synthetic flavins (LMC, RF, FMN, and FAD, Sigma Aldrich) under the same conditions indicated that measured EH values are buffered at +270 ± 20 mV and -230 ± 50 mV when oxidized and reduced flavin species dominate, respectively. Moreover, based on the temporal changes in EH, we speculate that NO3- reduction by S. oneidensis consumes reduced flavins (i.e., NO3- accepts electrons from reduced flavins) and generates oxidized flavins, thus buffering EH at +255 mV. By contrast, NO2- reduction to NH4+ is independent of flavin speciation, which leads to the accumulation of reduced flavins in the solution and

  15. Antimicrobial Materials for Advanced Microbial Control in Spacecraft Water Systems

    Science.gov (United States)

    Birmele, Michele; Caro, Janicce; Newsham, Gerard; Roberts, Michael; Morford, Megan; Wheeler, Ray

    2012-01-01

    Microbial detection, identification, and control are essential for the maintenance and preservation of spacecraft water systems. Requirements set by NASA put limitations on the energy, mass, materials, noise, cost, and crew time that can be devoted to microbial control. Efforts are being made to attain real-time detection and identification of microbial contamination in microgravity environments. Research for evaluating technologies for capability enhancement on-orbit is currently focused on the use of adenosine triphosphate (ATP) analysis for detection purposes and polymerase chain reaction (peR) for microbial identification. Additional research is being conducted on how to control for microbial contamination on a continual basis. Existing microbial control methods in spacecraft utilize iodine or ionic silver biocides, physical disinfection, and point-of-use sterilization filters. Although these methods are effective, they require re-dosing due to loss of efficacy, have low human toxicity thresholds, produce poor taste, and consume valuable mass and crew time. Thus, alternative methods for microbial control are needed. This project also explores ultraviolet light-emitting diodes (UV-LEDs), surface passivation methods for maintaining residual biocide levels, and several antimicrobial materials aimed at improving current microbial control techniques, as well as addressing other materials presently under analysis and future directions to be pursued.

  16. Microbial profile and critical control points during processing of 'robo ...

    African Journals Online (AJOL)

    Microbial profile and critical control points during processing of 'robo' snack from ... the relevant critical control points especially in relation to raw materials and ... to the quality of the various raw ingredients used were the roasting using earthen

  17. Identification of External Critical Success Factors in Microbial Biotechnology Firms

    Directory of Open Access Journals (Sweden)

    Alireza AZIMI

    2013-03-01

    Full Text Available Microbial biotechnology is expected to change production methods, the products themselves and the structure of the industries in the new economies. Hopefully, countries in the Middle-East, Latin America, Asia and Africa have already recognized the importance of microbial biotechnology's promise. In this sense, the importance of externalities which might affect the success or failure of these companies becomes an issue of paramount importance. In the present study, we will try to identify the main external factors which could lead in the success of microbial biotechnology firms in Iran. To do so, the research follows a qualitative research design to answer this main question. Based on our findings, critical success factors are categorized in the following categories: General Environment (GE, Political Position (PP, Economic Position (EP, and Market Position (MP.

  18. Controlling microbial PHB synthesis via CRISPRi.

    Science.gov (United States)

    Li, Dan; Lv, Li; Chen, Jin-Chun; Chen, Guo-Qiang

    2017-07-01

    Microbial polyhydroxyalkanoates (PHA) are a family of biopolyesters with properties similar to petroleum plastics such as polyethylene (PE) or polypropylene (PP). Polyhydroxybutyrate (PHB) is the most common PHA known so far. Clustered regularly interspaced short palindromic repeats interference (CRISPRi), a technology recently developed to control gene expression levels in eukaryotic and prokaryotic genomes, was employed to regulate PHB synthase activity influencing PHB synthesis. Recombinant Escherichia coli harboring an operon of three PHB synthesis genes phaCAB cloned from Ralstonia eutropha, was transformed with various single guided RNA (sgRNA with its guide sequence of 20-23 bases) able to bind to various locations of the PHB synthase PhaC, respectively. Depending on the binding location and the number of sgRNA on phaC, CRISPRi was able to control the phaC transcription and thus PhaC activity. It was found that PHB content, molecular weight, and polydispersity were approximately in direct and reverse proportion to the PhaC activity, respectively. The higher the PhaC activity, the more the intracellular PHB accumulation, yet the less the PHB molecular weights and the wider the polydispersity. This study allowed the PHB contents to be controlled in the ranges of 1.47-75.21% cell dry weights, molecular weights from 2 to 6 millions Dalton and polydispersity of 1.2 to 1.43 in 48 h shake flask studies. This result will be very important for future development of ultrahigh molecular weight PHA useful to meet high strength application requirements.

  19. Potential microbial risk factors related to soil amendments and irrigation water of potato crops.

    Science.gov (United States)

    Selma, M V; Allende, A; López-Gálvez, F; Elizaquível, P; Aznar, R; Gil, M I

    2007-12-01

    This study assesses the potential microbial risk factors related to the use of soil amendments and irrigation water on potato crops, cultivated in one traditional and two intensive farms during two harvest seasons. The natural microbiota and potentially pathogenic micro-organisms were evaluated in the soil amendment, irrigation water, soil and produce. Uncomposted amendments and residual and creek water samples showed the highest microbial counts. The microbial load of potatoes harvested in spring was similar among the tested farms despite the diverse microbial levels of Listeria spp. and faecal coliforms in the potential risk sources. However, differences in total coliform load of potato were found between farms cultivated in the autumn. Immunochromatographic rapid tests and the BAM's reference method (Bacteriological Analytical Manual; AOAC International) were used to detect Escherichia coli O157:H7 from the potential risk sources and produce. Confirmation of the positive results by polymerase chain reaction procedures showed that the immunochromatographic assay was not reliable as it led to false-positive results. The potentially pathogenic micro-organisms of soil amendment, irrigation water and soil samples changed with the harvest seasons and the use of different agricultural practices. However, the microbial load of the produce was not always influenced by these risk sources. Improvements in environmental sample preparation are needed to avoid interferences in the use of immunochromatographic rapid tests. The potential microbial risk sources of fresh produce should be regularly controlled using reliable detection methods to guarantee their microbial safety.

  20. Microbial control of arthropod pests of tropical tree fruits.

    Science.gov (United States)

    Dolinski, Claudia; Lacey, Lawrence A

    2007-01-01

    A multitude of insects and mites attack fruit crops throughout the tropics. The traditional method for controlling most of these pests is the application of chemical pesticides. Growing concern on the negative environmental effects has encouraged the development of alternatives. Inundatively and inoculatively applied microbial control agents (virus, bacteria, fungi, and entomopathogenic nematodes) have been developed as alternative control methods of a wide variety of arthropods including tropical fruit pests. The majority of the research and applications in tropical fruit agroecosystems has been conducted in citrus, banana, coconut, and mango. Successful microbial control initiatives of citrus pests and mites have been reported. Microbial control of arthropod pests of banana includes banana weevil, Cosmopolites sordidus Germar (Coleoptera: Curculionidae) (with EPNs and fungi) among others Oryctes rhinoceros (L.) is one of the most important pests of coconut and one of the most successful uses of non-occluded virus for classical biological control. Key pests of mango that have been controlled with microbial control agents include fruit flies (Diptera: Tephritidae) (with EPNs and fungi), and other pests. Also successful is the microbial control of arthropod pests of guava, papaya and pineapple. The challenge towards a broader application of entomopathogens is the development of successful combinations of entomopathogens, predators, and parasitoids along with other interventions to produce effective and sustainable pest management.

  1. Microbial Character Related Sulfur Cycle under Dynamic Environmental Factors Based on the Microbial Population Analysis in Sewerage System.

    Science.gov (United States)

    Dong, Qian; Shi, Hanchang; Liu, Yanchen

    2017-01-01

    The undesired sulfur cycle derived by microbial population can ultimately causes the serious problems of sewerage systems. However, the microbial community characters under dynamic environment factors in actual sewerage system is still not enough. This current study aimed to character the distributions and compositions of microbial communities that participate in the sulfur cycle under the dynamic environmental conditions in a local sewerage system. To accomplish this, microbial community compositions were assessed using 454 high-throughput sequencing (16S rDNA) combined with dsrB gene-based denaturing gradient gel electrophoresis. The results indicated that a higher diversity of microbial species was present at locations in sewers with high concentrations of H 2 S. Actinobacteria and Proteobacteria were dominant in the sewerage system, while Actinobacteria alone were dominant in regions with high concentrations of H 2 S. Specifically, the unique operational taxonomic units could aid to characterize the distinct microbial communities within a sewerage manhole. The proportion of sulfate-reducing bacteria, each sulfur-oxidizing bacteria (SOB) were strongly correlated with the liquid parameters (DO, ORP, COD, Sulfide, NH 3 -N), while the Mycobacterium and Acidophilic SOB (M&A) was strongly correlated with gaseous factors within the sewer, such as H 2 S, CH 4 , and CO. Identifying the distributions and proportions of critical microbial communities within sewerage systems could provide insights into how the microbial sulfur cycle is affected by the dynamic environmental conditions that exist in sewers and might be useful for explaining the potential sewerage problems.

  2. Microbial control of caged population of Zonocerus variegatus using ...

    African Journals Online (AJOL)

    Microbial control of caged populations of Zonocerus variegatus was carried out using indigenous fungal entomopathogens isolated from the grasshopper's cadaver. Bioassay response indicated a dose-dependent mortality coupled with drastic reduction in food consumption among spores infected grasshoppers. Lethal time ...

  3. Factors influencing the microbial safety of fresh produce: a review.

    Science.gov (United States)

    Olaimat, Amin N; Holley, Richard A

    2012-10-01

    Increased consumption, larger scale production and more efficient distribution of fresh produce over the past two decades have contributed to an increase in the number of illness outbreaks caused by this commodity. Pathogen contamination of fresh produce may originate before or after harvest, but once contaminated produce is difficult to sanitize. The prospect that some pathogens invade the vascular system of plants and establish "sub-clinical" infection needs to be better understood to enable estimation of its influence upon risk of human illness. Conventional surface sanitation methods can reduce the microbial load, but cannot eliminate pathogens if present. Chlorine dioxide, electrolyzed water, UV light, cold atmospheric plasma, hydrogen peroxide, organic acids and acidified sodium chlorite show promise, but irradiation at 1 kGy in high oxygen atmospheres may prove to be the most effective means to assure elimination of both surface and internal contamination of produce by pathogens. Pathogens of greatest current concern are Salmonella (tomatoes, seed sprouts and spices) and Escherichia coli O157:H7 on leafy greens (spinach and lettuce). This review considers new information on illness outbreaks caused by produce, identifies factors which influence their frequency and size and examines intervention effectiveness. Research needed to increase our understanding of the factors influencing microbial safety of fresh produce is addressed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Nutrient Enrichment Mediates the Relationships of Soil Microbial Respiration with Climatic Factors in an Alpine Meadow

    Directory of Open Access Journals (Sweden)

    Ning Zong

    2015-01-01

    Full Text Available Quantifying the effects of nutrient additions on soil microbial respiration (Rm and its contribution to soil respiration (Rs are of great importance for accurate assessment ecosystem carbon (C flux. Nitrogen (N addition either alone (coded as LN and HN or in combination with phosphorus (P (coded as LN + P and HN + P were manipulated in a semiarid alpine meadow on the Tibetan Plateau since 2008. Either LN or HN did not affect Rm, while LN + P enhanced Rm during peak growing periods, but HN + P did not affect Rm. Nutrient addition also significantly affected Rm/Rs, and the correlations of Rm/Rs with climatic factors varied with years. Soil water content (Sw was the main factor controlling the variations of Rm/Rs. During the years with large rainfall variations, Rm/Rs was negatively correlated with Sw, while, in years with even rainfall, Rm/Rs was positively correlated with Sw. Meanwhile, in N + P treatments the controlling effects of climatic factors on Rm/Rs were more significant than those in CK. Our results indicate that the sensitivity of soil microbes to climatic factors is regulated by nutrient enrichment. The divergent effects of Sw on Rm/Rs suggest that precipitation distribution patterns are key factors controlling soil microbial activities and ecosystem C fluxes in semiarid alpine meadow ecosystems.

  5. Microbial control of hydrogen sulfide production

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, A.D.; Bhupathiraju, V.K.; Wofford, N.; McInerney, M.J. [Univ. of Oklahoma, Tulsa, OK (United States)] [and others

    1995-12-31

    A sulfide-resistant strain of Thiobacillus denitrificans, strain F, prevented the accumulation of sulfide by Desulfovibrio desulfuricans when both organisms were grown in liquid medium. The wild-type strain of T. denitrificans did not prevent the accumulation of sulfide produced by D. desulfuricans. Strain F also prevented the accumulation of sulfide by a mixed population of sulfate-reducing bacteria enriched from an oil field brine. Fermentation balances showed that strain F stoichiometrically oxidized the sulfide produced by D. desulfuricans and the oil field brine enrichment to sulfate. The ability of a strain F to control sulfide production in an experimental system of cores and formation water from the Redfield, Iowa, natural gas storage facility was also investigated. A stable, sulfide-producing biofilm was established in two separate core systems, one of which was inoculated with strain F while the other core system (control) was treated in an identical manner, but was not inoculated with strain F. When formation water with 10 mM acetate and 5 mM nitrate was injected into both core systems, the effluent sulfide concentrations in the control core system ranged from 200 to 460 {mu}M. In the test core system inoculated with strain F, the effluent sulfide concentrations were lower, ranging from 70 to 110 {mu}M. In order to determine whether strain F could control sulfide production under optimal conditions for sulfate-reducing bacteria, the electron donor was changed to lactate and inorganic nutrients (nitrogen and phosphate sources) were added to the formation water. When nutrient-supplemented formation water with 3.1 mM lactate and 10 mM nitrate was used, the effluent sulfide concentrations of the control core system initially increased to about 3,800 {mu}M, and then decreased to about 1,100 {mu}M after 5 weeks. However, in the test core system inoculated with strain F, the effluent sulfide concentrations were much lower, 160 to 330 {mu}M.

  6. Trends in microbial control techniques for poultry products.

    Science.gov (United States)

    Silva, Filomena; Domingues, Fernanda C; Nerín, Cristina

    2018-03-04

    Fresh poultry meat and poultry products are highly perishable foods and high potential sources of human infection due to the presence of several foodborne pathogens. Focusing on the microbial control of poultry products, the food industry generally implements numerous preventive measures based on the Hazard Analysis and Critical Control Points (HACCP) food safety management system certification together with technological steps, such as refrigeration coupled to modified atmosphere packaging that are able to control identified potential microbial hazards during food processing. However, in recent years, to meet the demand of consumers for minimally processed, high-quality, and additive-free foods, technologies are emerging associated with nonthermal microbial inactivation, such as high hydrostatic pressure, irradiation, and natural alternatives, such as biopreservation or the incorporation of natural preservatives in packaging materials. These technologies are discussed throughout this article, emphasizing their pros and cons regarding the control of poultry microbiota and their effects on poultry sensory properties. The discussion for each of the preservation techniques mentioned will be provided with as much detail as the data and studies provided in the literature for poultry meat and products allow. These new approaches, on their own, have proved to be effective against a wide range of microorganisms in poultry meat. However, since some of these emergent technologies still do not have full consumer's acceptability and, taking into consideration the hurdle technology concept for poultry processing, it is suggested that they will be used as combined treatments or, more frequently, in combination with modified atmosphere packaging.

  7. Microbial fouling control in heat exchangers

    International Nuclear Information System (INIS)

    McCoy, W.F.

    1991-01-01

    Biofilm formation in turbulent flow has been studied a great deal during the last 15 years. Such studies have provided the basis for further experiments designed to test the efficacy of industrial antimicrobials against biofilms in laboratory models and in actual real-world industrial water-treatment programs. Biofilm microbiology is relevant from the industrial perspective because adherent populations of microorganisms often cause an economic impact on industrial processes. For example, it is the adherent population of microorganisms in cooling-water systems that can eventually contribute to significant heat transfer and fluid frictional resistances. The microbiology of biofilms in heat exchangers can be related to the performance of industrial antimicrobials. The development of fouling biofilms and methods to quantitatively observe the effect of biofouling control agents are discussed in this paper

  8. Environmental controls on microbial communities in continental serpentinite fluids

    Directory of Open Access Journals (Sweden)

    Melitza eCrespo-Medina

    2014-11-01

    Full Text Available Geochemical reactions associated with serpentinization alter the composition of dissolved organic compounds in circulating fluids and potentially liberate mantle-derived carbon and reducing power to support subsurface microbial communities. Previous studies have identified Betaproteobacteria from the order Burkholderiales and bacteria from the order Clostridiales as key components of the serpentinite–hosted microbiome, however there is limited knowledge of their metabolic capabilities or growth characteristics. In an effort to better characterize microbial communities, their metabolism, and factors limiting their activities, microcosm experiments were designed with fluids collected from several monitoring wells at the Coast Range Ophiolite Microbial Observatory (CROMO in northern California during expeditions in March and August 2013. The incubations were initiated with a hydrogen atmosphere and a variety of carbon sources (carbon dioxide, methane, acetate and formate, with and without the addition of nutrients and electron acceptors. Growth was monitored by direct microscopic counts; DNA yield and community composition was assessed at the end of the three month incubation. For the most part, results indicate that bacterial growth was favored by the addition of acetate and methane, and that the addition of nutrients and electron acceptors had no significant effect on microbial growth, suggesting no nutrient- or oxidant-limitation. However the addition of sulfur amendments led to different community compositions. The dominant organisms at the end of the incubations were closely related to Dethiobacter sp. and to the family Comamonadaceae, which are also prominent in culture-independent gene sequencing surveys. These experiments provide one of first insights into the biogeochemical dynamics of the serpentinite subsurface environment and will facilitate experiments to trace microbial activities in serpentinizing ecosystems.

  9. Representing Microbial Dormancy in Soil Decomposition Models Improves Model Performance and Reveals Key Ecosystem Controls on Microbial Activity

    Science.gov (United States)

    He, Y.; Yang, J.; Zhuang, Q.; Wang, G.; Liu, Y.

    2014-12-01

    Climate feedbacks from soils can result from environmental change and subsequent responses of plant and microbial communities and nutrient cycling. Explicit consideration of microbial life history traits and strategy may be necessary to predict climate feedbacks due to microbial physiology and community changes and their associated effect on carbon cycling. In this study, we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of dormancy at six temperate forest sites with observed soil efflux ranged from 4 to 10 years across different forest types. We then extrapolated the model to all temperate forests in the Northern Hemisphere (25-50°N) to investigate spatial controls on microbial and soil C dynamics. Both models captured the observed soil heterotrophic respiration (RH), yet no-dormancy model consistently exhibited large seasonal amplitude and overestimation in microbial biomass. Spatially, the total RH from temperate forests based on dormancy model amounts to 6.88PgC/yr, and 7.99PgC/yr based on no-dormancy model. However, no-dormancy model notably overestimated the ratio of microbial biomass to SOC. Spatial correlation analysis revealed key controls of soil C:N ratio on the active proportion of microbial biomass, whereas local dormancy is primarily controlled by soil moisture and temperature, indicating scale-dependent environmental and biotic controls on microbial and SOC dynamics. These developments should provide essential support to modeling future soil carbon dynamics and enhance the avenue for collaboration between empirical soil experiment and modeling in the sense that more microbial physiological measurements are needed to better constrain and evaluate the models.

  10. Mineralogical Control on Microbial Diversity in a Weathered Granite?

    Science.gov (United States)

    Gleeson, D.; Clipson, N.; McDermott, F.

    2003-12-01

    Mineral transformation reactions and the behaviour of metals in rock and soils are affected not only by physicochemical parameters but also by biological factors, particularly by microbial activity. Microbes inhabit a wide range of niches in surface and subsurface environments, with mineral-microbe interactions being generally poorly understood. The focus of this study is to elucidate the role of microbial activity in the weathering of common silicate minerals in granitic rocks. A site in the Wicklow Mountains (Ireland) has been identified that consists of an outcrop surface of Caledonian (ca. 400 million years old) pegmatitic granite from which large intact crystals of variably weathered muscovite, plagioclase, K-feldspar and quartz were sampled, together with whole-rock granite. Culture-based microbial approaches have been widely used to profile microbial communities, particularly from copiotrophic environments, but it is now well established that for oligotrophic environments such as those that would be expected on weathering faces, perhaps less than 1% of microbial diversity can be profiled by cultural means. A number of culture-independent molecular based approaches have been developed to profile microbial diversity and community structure. These rely on successfully isolating environmental DNA from a given environment, followed by the use of the polymerase chain reaction (PCR) to amplify the typically small quantities of extracted DNA. Amplified DNA can then be analysed using cloning based approaches as well as community fingerprinting systems such as denaturing gradient gel electrophoresis (DGGE), terminal restriction fragment length polymorphism (TRFLP) and ribosomal intergenic spacer analysis (RISA). Community DNA was extracted and the intergenic spacer region (ITS) between small (16S) and large (23S) bacterial subunit rRNA genes was amplified. RISA fragments were then electrophoresed on a non-denaturing polyacrylamide gel. Banding patterns suggest that

  11. Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories

    DEFF Research Database (Denmark)

    Wigneswaran, Vinoth; Amador Hierro, Cristina Isabel; Jelsbak, Lotte

    2016-01-01

    Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial co...

  12. Control of malodorous hydrogen sulfide compounds using microbial fuel cell.

    Science.gov (United States)

    Eaktasang, Numfon; Min, Hyeong-Sik; Kang, Christina; Kim, Han S

    2013-10-01

    In this study, a microbial fuel cell (MFC) was used to control malodorous hydrogen sulfide compounds generated from domestic wastewaters. The electricity production demonstrated a distinct pattern of a two-step increase during 170 h of system run: the first maximum current density was 118.6 ± 7.2 mA m⁻² followed by a rebound of current density increase, reaching the second maximum of 176.8 ± 9.4 mA m⁻². The behaviors of the redox potential and the sulfate level in the anode compartment indicated that the microbial production of hydrogen sulfide compounds was suppressed in the first stage, and the hydrogen sulfide compounds generated from the system were removed effectively as a result of their electrochemical oxidation, which contributed to the additional electricity production in the second stage. This was also directly supported by sulfur deposits formed on the anode surface, which was confirmed by analyses on those solids using a scanning electron microscope equipped with energy dispersive X-ray spectroscopy as well as an elemental analyzer. To this end, the overall reduction efficiencies for HS⁻ and H₂S(g) were as high as 67.5 and 96.4 %, respectively. The correlations among current density, redox potential, and sulfate level supported the idea that the electricity signal generated in the MFC can be utilized as a potential indicator of malodor control for the domestic wastewater system.

  13. Cost of microbial larviciding for malaria control in rural Tanzania.

    Science.gov (United States)

    Rahman, Rifat; Lesser, Adriane; Mboera, Leonard; Kramer, Randall

    2016-11-01

    Microbial larviciding may be a potential supplement to conventional malaria vector control measures, but scant information on its relative implementation costs and effectiveness, especially in rural areas, is an impediment to expanding its uptake. We perform a costing analysis of a seasonal microbial larviciding programme in rural Tanzania. We evaluated the financial and economic costs from the perspective of the public provider of a 3-month, community-based larviciding intervention implemented in twelve villages in the Mvomero District of Tanzania in 2012-2013. Cost data were collected from financial reports and invoices and through discussion with programme administrators. Sensitivity analysis explored the robustness of our results to varying key parameters. Over the 2-year study period, approximately 6873 breeding sites were treated with larvicide. The average annual economic costs of the larviciding intervention in rural Tanzania are estimated at 2014 US$ 1.44 per person protected per year (pppy), US$ 6.18 per household and US$ 4481.88 per village, with the larvicide and staffing accounting for 14% and 58% of total costs, respectively. We found the costs pppy of implementing a seasonal larviciding programme in rural Tanzania to be comparable to the costs of other larviciding programmes in urban Tanzania and rural Kenya. Further research should evaluate the cost-effectiveness of larviciding relative to, and in combination with, other vector control strategies in rural settings. © 2016 John Wiley & Sons Ltd.

  14. The role of microbial low-molecular-weight autoregulatory factors (alkylhydroxybenzenes) in resistance of microorganisms to radiation and heat shock

    Science.gov (United States)

    El-Registan, Galina I.; Mulyukin, Andrey L.; Nikolaev, Yuri A.; Stepanenko, Irina Yu.; Kozlova, Alla N.; Martirosova, Elena I.; Shanenko, Elena F.; Strakhovskaya, Marina G.; Revina, Aleksandra A.

    Low-molecular-weight cell-to-cell communication factors are produced by various pro- and eukaryotes and involved in autoregulation of the growth and development of microbial cultures. As for some bacterial and yeast species, these factors were identified as isomers and homologues of alkylhydroxybenzenes (AHB). Depending on the concentration, they participate in controlling the transition to stationary phase, entering the resting state, and stress resistance of vegetative cells to gamma-irradiation, photooxidation (singlet oxygen), and heat shock. Chemical analogues of microbial AHB protected microbial cultures from stressful situations and exerted (1) the stabilizing activity toward macromolecules and (2) the ability to scavenge active oxygen species. The stabilizing effect of AHBs resulted from their complex formation with protected macromolecules due to intermolecular hydrogen bonds, hydrophobic and electrostatic interactions and was demonstrated on models of individual enzymes (trypsin). Particularly, AHBs protected the yeast from the action of (a) active oxygen species formed during gamma-irradiation (500 Gy, 1.96 Gy/s) or (b) singlet oxygen generated in cells photosensitized by chlorin e 6 (10 μg/L). It is important that microbial AHBs were not species-specific and defended cultured microbial and animal cells from the action of organic toxicants. The use of AHBs as protectants and adaptogens is discussed as well as perspectives of further investigations.

  15. Spatial variation in microbial processes controlling carbon mineralization within soils and sediments

    Energy Technology Data Exchange (ETDEWEB)

    Fendorf, Scott [Stanford Univ., CA (United States); Kleber, Markus [Oregon State Univ., Corvallis, OR (United States); Nico, Peter [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2017-10-19

    Soils have a defining role in global carbon cycling, having one of the largest dynamic stocks of C on earth—3300 Pg of C are stored in soils, which is three-times the amount stored in the atmosphere and more than the terrestrial land plants. An important control on soil organic matter (SOM) quantities is the mineralization rate. It is well recognized that the rate and extent of SOM mineralization is affected by climatic factors and mineral-organic matter associations. What remained elusive is to what extent constraints on microbial metabolism induced by the respiratory pathway, and specifically the electron acceptor in respiration, control overall rates of carbon mineralization in soils. Therefore, physical factors limiting oxygen diffusion such as soil texture and aggregate size (soil structure) may therefore be central controls on C mineralization rates. The goal of our research was therefore to determine if variations in microbial metabolic rates induced by anaerobic microsites in soils are a major control on SOM mineralization rates and thus storage. We performed a combination of laboratory experiments and field investigations will be performed to fulfill our research objectives. We used laboratory studies to examine fundamental factors of respiratory constraints (i.e., electron acceptor) on organic matter mineralization rates. We ground our laboratory studies with both manipulation of field samples and in-field measurements. Selection of the field sites is guided by variation in soil texture and structure while having (other environmental/soil factors constant. Our laboratory studies defined redox gradients and variations in microbial metabolism operating at the aggregate-scale (cm-scale) within soils using a novel constructed diffusion reactor. We further examined micro-scale variation in terminal electron accepting processes and resulting C mineralization rates within re-packed soils. A major outcome of our research is the ability to quantitatively place

  16. Learning Microbial Community Structures with Supervised and Unsupervised Non-negative Matrix Factorization.

    Science.gov (United States)

    Cai, Yun; Gu, Hong; Kenney, Toby

    2017-08-31

    Learning the structure of microbial communities is critical in understanding the different community structures and functions of microbes in distinct individuals. We view microbial communities as consisting of many subcommunities which are formed by certain groups of microbes functionally dependent on each other. The focus of this paper is on methods for extracting the subcommunities from the data, in particular Non-Negative Matrix Factorization (NMF). Our methods can be applied to both OTU data and functional metagenomic data. We apply the existing unsupervised NMF method and also develop a new supervised NMF method for extracting interpretable information from classification problems. The relevance of the subcommunities identified by NMF is demonstrated by their excellent performance for classification. Through three data examples, we demonstrate how to interpret the features identified by NMF to draw meaningful biological conclusions and discover hitherto unidentified patterns in the data. Comparing whole metagenomes of various mammals, (Muegge et al., Science 332:970-974, 2011), the biosynthesis of macrolides pathway is found in hindgut-fermenting herbivores, but not carnivores. This is consistent with results in veterinary science that macrolides should not be given to non-ruminant herbivores. For time series microbiome data from various body sites (Caporaso et al., Genome Biol 12:50, 2011), a shift in the microbial communities is identified for one individual. The shift occurs at around the same time in the tongue and gut microbiomes, indicating that the shift is a genuine biological trait, rather than an artefact of the method. For whole metagenome data from IBD patients and healthy controls (Qin et al., Nature 464:59-65, 2010), we identify differences in a number of pathways (some known, others new). NMF is a powerful tool for identifying the key features of microbial communities. These identified features can not only be used to perform difficult

  17. Microbial Populations of Stony Meteorites: Substrate Controls on First Colonizers

    Directory of Open Access Journals (Sweden)

    Alastair W. Tait

    2017-06-01

    Full Text Available Finding fresh, sterilized rocks provides ecologists with a clean slate to test ideas about first colonization and the evolution of soils de novo. Lava has been used previously in first colonizer studies due to the sterilizing heat required for its formation. However, fresh lava typically falls upon older volcanic successions of similar chemistry and modal mineral abundance. Given enough time, this results in the development of similar microbial communities in the newly erupted lava due to a lack of contrast between the new and old substrates. Meteorites, which are sterile when they fall to Earth, provide such contrast because their reduced and mafic chemistry commonly differs to the surfaces on which they land; thus allowing investigation of how community membership and structure respond to this new substrate over time. We conducted 16S rRNA gene analysis on meteorites and soil from the Nullarbor Plain, Australia. We found that the meteorites have low species richness and evenness compared to soil sampled from directly beneath each meteorite. Despite the meteorites being found kilometers apart, the community structure of each meteorite bore more similarity to those of other meteorites (of similar composition than to the community structure of the soil on which it resided. Meteorites were dominated by sequences that affiliated with the Actinobacteria with the major Operational Taxonomic Unit (OTU classified as Rubrobacter radiotolerans. Proteobacteria and Bacteroidetes were the next most abundant phyla. The soils were also dominated by Actinobacteria but to a lesser extent than the meteorites. We also found OTUs affiliated with iron/sulfur cycling organisms Geobacter spp. and Desulfovibrio spp. This is an important finding as meteorites contain abundant metal and sulfur for use as energy sources. These ecological findings demonstrate that the structure of the microbial community in these meteorites is controlled by the substrate, and will not

  18. Large-scale environmental controls on microbial biofilms in high-alpine streams

    Directory of Open Access Journals (Sweden)

    T. J. Battin

    2004-01-01

    Full Text Available Glaciers are highly responsive to global warming and important agents of landscape heterogeneity. While it is well established that glacial ablation and snowmelt regulate stream discharge, linkage among streams and streamwater geochemistry, the controls of these factors on stream microbial biofilms remain insufficiently understood. We investigated glacial (metakryal, hypokryal, groundwater-fed (krenal and snow-fed (rhithral streams - all of them representative for alpine stream networks - and present evidence that these hydrologic and hydrogeochemical factors differentially affect sediment microbial biofilms. Average microbial biomass and bacterial carbon production were low in the glacial streams, whereas bacterial cell size, biomass, and carbon production were higher in the tributaries, most notably in the krenal stream. Whole-cell in situ fluorescence hybridization revealed reduced detection rates of the Eubacteria and higher abundance of α-Proteobacteria in the glacial stream, a pattern that most probably reflects the trophic status of this ecosystem. Our data suggest low flow during the onset of snowmelt and autumn as a short period (hot moment of favorable environmental conditions with pulsed inputs of allochthonous nitrate and dissolved organic carbon, and with disproportionately high microbial growth. Tributaries are relatively more constant and favorable environments than kryal streams, and serve as possible sources of microbes and organic matter to the main glacial channel during periods (e.g., snowmelt of elevated hydrologic linkage among streams. Ice and snow dynamics - and their impact on the amount and composition of dissolved organic matter - have a crucial impact on stream biofilms, and we thus need to consider microbes and critical hydrological episodes in future models of alpine stream communities.

  19. Microbial control of the dark end of the biological pump

    NARCIS (Netherlands)

    Herndl, G.J.; Reinthaler, T.

    2013-01-01

    A fraction of the carbon captured by phytoplankton in the sunlit surface ocean sinks to depth as dead organic matter and faecal material. The microbial breakdown of this material in the subsurface ocean generates carbon dioxide. Collectively, this microbially mediated flux of carbon from the

  20. The role of microbial low-molecular-weight autoregulatory factors (alkylhydroxybenzenes) in resistance of microorganisms to radiation

    Science.gov (United States)

    El-Registan, G. I.; Mulyukin, A. L.; Nikolaev, Yu. A.; Stepanenko, I. Yu.; Shanenko, E. A.; Strakhovskaya, M. G.; Revina, A. A.

    Low-molecular-weight cell-to-cell communication factors are produced by various pro- and eukaryotes and involved in autoregulation of the growth and development of microbial cultures. As for some bacterial and yeast species, these factors were identified as isomers and homologs of alkylhydroxybenzenes (AHBs). Depending on the concentration, they participate in controlling the transition to stationary phase, entering the resting state, and stress resistance of vegetative cells to gamma-irradiation, photooxidation (singlet oxygen), heat shock. Chemical analogs of microbial AHBs protected microbial cultures from stressful situations and prolonged starvation and exerted (1) the stabilizing activity toward biomacromolecules and supermolecular structures (cell membranes) and (2) the ability to scavenge active oxygen species. The stabilizing effect of AHBs as chemical chaperones resulted from their complex formation with protected macromolecules due to intermolecular hydrogen bonds, hydrophobic and electrostatic interactions and was demonstrated on models of individual enzymes (trypsin, amylase, etc.). The action of AHBs as active oxygen species scavengers was related to their oxidative conversion to water-insoluble polymeric products. Particularly, AHBs protected the yeast from the action of (a) active oxygen species formed during gamma-irradiation (50 krad, 196 rad/sec) or (b) singlet oxygen generated in cells photosensitized by chlorin e6 (10 mkg/L). It is important that microbial AHBs were not species-specific and defended cultured animal cells (ras-transformed fibroblasts) from the action of organic toxicants. The use of AHBs as protectants and adaptogens will be discussed as well as perspectives of further investigations.

  1. Available nitrogen is the key factor influencing soil microbial functional gene diversity in tropical rainforest.

    Science.gov (United States)

    Cong, Jing; Liu, Xueduan; Lu, Hui; Xu, Han; Li, Yide; Deng, Ye; Li, Diqiang; Zhang, Yuguang

    2015-08-20

    Tropical rainforests cover over 50% of all known plant and animal species and provide a variety of key resources and ecosystem services to humans, largely mediated by metabolic activities of soil microbial communities. A deep analysis of soil microbial communities and their roles in ecological processes would improve our understanding on biogeochemical elemental cycles. However, soil microbial functional gene diversity in tropical rainforests and causative factors remain unclear. GeoChip, contained almost all of the key functional genes related to biogeochemical cycles, could be used as a specific and sensitive tool for studying microbial gene diversity and metabolic potential. In this study, soil microbial functional gene diversity in tropical rainforest was analyzed by using GeoChip technology. Gene categories detected in the tropical rainforest soils were related to different biogeochemical processes, such as carbon (C), nitrogen (N) and phosphorus (P) cycling. The relative abundance of genes related to C and P cycling detected mostly derived from the cultured bacteria. C degradation gene categories for substrates ranging from labile C to recalcitrant C were all detected, and gene abundances involved in many recalcitrant C degradation gene categories were significantly (P rainforest. Soil available N could be the key factor in shaping the soil microbial functional gene structure and metabolic potential.

  2. Control of Clostridium difficile infection by defined microbial communities

    Science.gov (United States)

    Collins, James

    2017-01-01

    Summary Each year in the United States, billions of dollars are spent combating almost half a million Clostridium difficile infections (CDI) and trying to reduce the ~29,000 patient deaths where C. difficile has an attributed role (1). In Europe, disease prevalence varies by country and level of surveillance, though yearly costs are estimated at €3 billion (2). One factor contributing to the significant healthcare burden of C. difficile is the relatively high frequency of recurrent C. difficile infections(3). Recurrent C. difficile infection (rCDI), i.e., a second episode of symptomatic CDI occurring within eight weeks of successful initial CDI treatment, occurs in ~25% of patients with 35-65% of these patients experiencing multiple episodes of recurrent disease(4, 5). Using microbial communities to treat rCDI, either as whole fecal transplants or as defined consortia of bacterial isolates have shown great success (in the case of fecal transplants) or potential promise (in the case of defined consortia of isolates). This review will briefly summarize the epidemiology and physiology of C. difficile infection, describe our current understanding of how fecal microbiota transplants treat recurrent CDI, and outline potential ways through which that knowledge can be used to rationally-design and test alternative microbe-based therapeutics. PMID:28936948

  3. Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories.

    Science.gov (United States)

    Wigneswaran, Vinoth; Amador, Cristina Isabel; Jelsbak, Lotte; Sternberg, Claus; Jelsbak, Lars

    2016-01-01

    Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial communities depends, to a large extent, on our knowledge of these interactions. This review highlights the recent advances regarding molecular characterization of microbe-microbe interactions that modulate community structure, activity, and stability, and aims to illustrate how these findings have helped us reach an engineering-level understanding of microbial communities in relation to both human health and industrial biotechnology.

  4. Divergence of dominant factors in soil microbial communities and functions in forest ecosystems along a climatic gradient

    Science.gov (United States)

    Xu, Zhiwei; Yu, Guirui; Zhang, Xinyu; He, Nianpeng; Wang, Qiufeng; Wang, Shengzhong; Xu, Xiaofeng; Wang, Ruili; Zhao, Ning

    2018-03-01

    Soil microorganisms play an important role in regulating nutrient cycling in terrestrial ecosystems. Most of the studies conducted thus far have been confined to a single forest biome or have focused on one or two controlling factors, and few have dealt with the integrated effects of climate, vegetation, and soil substrate availability on soil microbial communities and functions among different forests. In this study, we used phospholipid-derived fatty acid (PLFA) analysis to investigate soil microbial community structure and extracellular enzymatic activities to evaluate the functional potential of soil microbes of different types of forests in three different climatic zones along the north-south transect in eastern China (NSTEC). Both climate and forest type had significant effects on soil enzyme activities and microbial communities with considerable interactive effects. Except for soil acid phosphatase (AP), the other three enzyme activities were much higher in the warm temperate zone than in the temperate and the subtropical climate zones. The soil total PLFAs and bacteria were much higher in the temperate zone than in the warm temperate and the subtropical zones. The soil β-glucosidase (BG) and N-acetylglucosaminidase (NAG) activities were highest in the coniferous forest. Except for the soil fungi and fungi-bacteria (F/B), the different groups of microbial PLFAs were much higher in the conifer broad-leaved mixed forests than in the coniferous forests and the broad-leaved forests. In general, soil enzyme activities and microbial PLFAs were higher in primary forests than in secondary forests in temperate and warm temperate regions. In the subtropical region, soil enzyme activities were lower in the primary forests than in the secondary forests and microbial PLFAs did not differ significantly between primary and secondary forests. Different compositions of the tree species may cause variations in soil microbial communities and enzyme activities. Our results

  5. Critical control points for the management of microbial growth in HVAC systems

    NARCIS (Netherlands)

    Gommers, S; Franchimon, F.; Bronswijk, van J.E.M.H.; Strøm-Tejsen, P; Olesen, BW; Wargocki, P; Zukowska, D; Toftum, J

    2008-01-01

    Office buildings with HVAC systems consistently report Sick Building Symptoms that are derived from microbial growth. We used the HACCP methodology to find the main critical control points (CCPs) for microbial management of HVAC systems in temperate climates. Desk research revealed relative humidity

  6. Control of microbially generated hydrogen sulfide in produced waters

    Energy Technology Data Exchange (ETDEWEB)

    Burger, E.D.; Vance, I.; Gammack, G.F.; Duncan, S.E.

    1995-12-31

    Production of hydrogen sulfide in produced waters due to the activity of sulfate-reducing bacteria (SRB) is a potentially serious problem. The hydrogen sulfide is not only a safety and environmental concern, it also contributes to corrosion, solids formation, a reduction in produced oil and gas values, and limitations on water discharge. Waters produced from seawater-flooded reservoirs typically contain all of the nutrients required to support SRB metabolism. Surface processing facilities provide a favorable environment in which SRB flourish, converting water-borne nutrients into biomass and H{sub 2}S. This paper will present results from a field trial in which a new technology for the biochemical control of SRB metabolism was successfully applied. A slip stream of water downstream of separators on a produced water handling facility was routed through a bioreactor in a side-steam device where microbial growth was allowed to develop fully. This slip stream was then treated with slug doses of two forms of a proprietary, nonbiocidal metabolic modifier. Results indicated that H{sub 2}S production was halted almost immediately and that the residual effect of the treatment lasted for well over one week.

  7. Evaluation of the Adequacy of GMP to Control Microbial Hazards in Dairy Factories in Fars Province

    Directory of Open Access Journals (Sweden)

    Sajjad Abdi no

    2016-07-01

    Full Text Available Background and Objectives: Pre-requisite programs (PRPs are “primary conditions and requirements essential for HACCP operations, which are crucial in food safety programs”. The present study was conducted to evaluate the impact of implementation of PRPs on the microbial parameters of pasteurized milk (according to the National Standard of Iran. Effectiveness of HACCP operation requirements and efficiency of Good Laboratory Practice (GLP were also evaluated in control of the above-mentioned microbial parameters. Materials and Methods: According to the approved checklist of the Vice-chancellor in Food and Drug affairs, PRPs of 26 factories were evaluated from March 2014 to March 2015 in two-month intervals, and their total and component scores were obtained along with the microbial parameters of pasteurized milk. Generalized Estimating Equations (GEEs were used to determine the significance of total score and the impact of its components on controlling microbial hazards. Results: There was a reverse significant relation between the total scores of the PRPs and microbial hygiene indices (total and coliform count which approves the effectiveness of operating the programs in controlling the mentioned microorganisms. Efficiency of each pre-requisite program was different in controlling the microbial parameters. Good Laboratory Practice (GLP had a prominent effect on controlling of the index microorganisms of hygienic operations. Overall, the results showed a little probability of contamination with E. coli in the pasteurized milk samples of Fars Province for which the statistical analysis was ignored. Conclusions: The exact operation of PRPs resulted in reduction of microbial parameters in a way that increasing the total score of PRPs led to decrease in microbial parameters of total count (TC, coliforms, molds and yeasts. The findings further suggest the application of this checklist in evaluation and prediction of microbial parameters. Keywords

  8. Flavin as an Indicator of the Rate-Limiting Factor for Microbial Current Production in Shewanella oneidensis MR-1

    International Nuclear Information System (INIS)

    Saito, Junki; Hashimoto, Kazuhito; Okamoto, Akihiro

    2016-01-01

    Microbial electrode catalysis such as microbial fuel cells or electrosynthesis involves electron exchange with the electrodes located at the cell exterior; i.e., extracellular electron transport (EET). Despite the vast amount of research on the kinetics of EET to optimize the catalysis rate, the relevance of other factors, including upstream metabolic reactions, has scarcely been investigated. Herein, we report an in vivo electrochemical assay to confirm whether EET limits anodic current production (j) for the lactate oxidation of Shewanella oneidensis MR-1. Addition of riboflavin, which specifically enhances the EET rate, increased j only in the early phase before j saturation. In contrast, when we removed a trace metal ion necessary for upstream reactions from the electrolyte, a significant decrease in j and the lactate consumption rate was observed only after j saturation. These data suggest that the limiting factor for j shifted from EET to upstream reactions, highlighting the general importance of enhancing, for example, microbial metabolism, especially for long-standing practical applications. Our concept to specifically control the rate of EET could be applicable to other bioelectrode catalysis systems as a strategy to monitor their rate-limiting factors.

  9. Factors affecting microbial activity in compacted clay-based sealing materials proposed for use in a deep geologic repository for used nuclear fuel

    International Nuclear Information System (INIS)

    Stroes-Gascoyne, S.; Hamon, C.J.; Dixon, D.A.; Kjartanson, B.K.

    2006-01-01

    Microbial activity in clay-based barriers immediately adjacent to metal used-fuel containers in a repository could affect the longevity of such containers. The current emphasis is, therefore, on reducing or minimizing microbial activity in such clay-based barriers through material composition design. Factors affecting microbial activity in clay-based materials were studied in large-scale and smaller-scale experiments. Results suggested that keeping water activity (a w ) values below ∼0.95 may minimize microbial activity in clay-based barrier materials. A considerably higher effective montmorillonite dry density (EMDD), which partially controls a w , is achievable for 100% bentonite than for previously proposed reference buffer materials, which contain only 50% bentonite. (author)

  10. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    International Nuclear Information System (INIS)

    Baldwin, Brett R.; Peacock, Aaron D.; Resch, Charles T.; Arntzen, Evan; Smithgall, Amanda N.; Pfiffner, Susan; Gan, M.; McKinley, James P.; Long, Philip E.; White, David C.

    2008-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  11. In Situ Microbial Community Control of the Stability of Bio-reduced Uranium

    Energy Technology Data Exchange (ETDEWEB)

    Baldwin, Brett, R.; Peacock, Aaron, D.; Resch, Charles, T.; Arntzen, Evan; Smithgall, Amanda, N.; Pfiffner, Susan; Gan, M.; McKinley, James, P.; Long, Philip, E.; White, David, C.

    2008-03-28

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is more soluble and thus more mobile. Field experiments at the Old Rifle UMTRA site have demonstrated that biostimulation by electron donor addition (acetate) promotes biological U(VI) reduction (2). However, U(VI) reduction is reversible and oxidative dissolution of precipitated U(IV) after the cessation of electron donor addition remains a critical issue for the application of biostimulation as a treatment technology. Despite the potential for oxidative dissolution, field experiments at the Old Rifle site have shown that rapid reoxidation of bio-reduced uranium does not occur and U(VI) concentrations can remain at approximately 20% of background levels for more than one year. The extent of post-amendment U(VI) removal and the maintenance of bioreduced uranium may result from many factors including U(VI) sorption to iron-containing mineral phases, generation of H2S or FeS0.9, or the preferential sorption of U(VI) by microbial cells or biopolymers, but the processes controlling the reduction and in situ reoxidation rates are not known. To investigate the role of microbial community composition in the maintenance of bioreduced uranium, in-well sediment incubators (ISIs) were developed allowing field deployment of amended and native sediments during on-going experiments at the site. Field deployment of the ISIs allows expedient interrogation of microbial community response to field environmental perturbations and varying geochemical conditions.

  12. Apple replant disease: role of microbial ecology in cause and control.

    Science.gov (United States)

    Mazzola, Mark; Manici, Luisa M

    2012-01-01

    Replant disease of apple is common to all major apple growing regions of the world. Difficulties in defining disease etiology, which can be exacerbated by abiotic factors, have limited progress toward developing alternatives to soil fumigation for disease control. However, the preponderance of data derived from studies of orchard soil biology employing multidisciplinary approaches has defined a complex of pathogens/parasites as causal agents of the disease. Approaches to manipulate microbial resources endemic to the orchard soil system have been proposed to induce a state of general soil suppressiveness to replant disease. Such a long-term strategy may benefit the existing orchard through extending the period of economic viability and reduce overall disease pressure to which young trees are exposed during establishment of successive plantings on the site. Alternatively, more near-term methods have been devised to achieve specific quantitative and qualitative changes in soil biology during the period of orchard renovation that may lead to effective disease suppression.

  13. Environmental and Geographical Factors Structure Soil Microbial Diversity in New Caledonian Ultramafic Substrates: A Metagenomic Approach.

    Directory of Open Access Journals (Sweden)

    Véronique Gourmelon

    Full Text Available Soil microorganisms play key roles in ecosystem functioning and are known to be influenced by biotic and abiotic factors, such as plant cover or edaphic parameters. New Caledonia, a biodiversity hotspot located in the southwest Pacific, is one-third covered by ultramafic substrates. These types of soils are notably characterised by low nutrient content and high heavy metal concentrations. Ultramafic outcrops harbour diverse vegetation types and remarkable plant diversity. In this study, we aimed to assess soil bacterial and fungal diversity in New Caledonian ultramafic substrates and to determine whether floristic composition, edaphic parameters and geographical factors affect this microbial diversity. Therefore, four plant formation types at two distinct sites were studied. These formations represent different stages in a potential chronosequence. Soil cores, according to a given sampling procedure, were collected to assess microbial diversity using a metagenomic approach, and to characterise the physico-chemical parameters. A botanical inventory was also performed. Our results indicated that microbial richness, composition and abundance were linked to the plant cover type and the dominant plant species. Furthermore, a large proportion of Ascomycota phylum (fungi, mostly in non-rainforest formations, and Planctomycetes phylum (bacteria in all formations were observed. Interestingly, such patterns could be indicators of past disturbances that occurred on different time scales. Furthermore, the bacteria and fungi were influenced by diverse edaphic parameters as well as by the interplay between these two soil communities. Another striking finding was the existence of a site effect. Differences in microbial communities between geographical locations may be explained by dispersal limitation in the context of the biogeographical island theory. In conclusion, each plant formation at each site possesses is own microbial community resulting from

  14. Mineralogical controls on surface colonization by sulfur-metabolizing microbial communities

    Science.gov (United States)

    Jones, A. A.; Bennett, P.

    2012-12-01

    When characterizing microbial diversity and the microbial ecosystem of the shallow subsurface the mineral matrix is generally assumed to be homogenous and unreactive. We report here experimental evidence that microorganisms colonize rock surfaces according to the rock's chemistry and the organism's metabolic requirements and tolerances. We investigated this phenomenon using laboratory biofilm reactors with both a pure culture of sulfur-oxidizing Thiothrix unzii and a mixed environmental sulfur-metabolizing community from Lower Kane, Cave, WY, USA. Reactors contained rock and mineral chips (calcite, albite, microcline, quartz, chert, Madison Limestone (ML), Madison Dolostone (MD), and basalt) amended with one of the two inoculants. Biomass of attached microorganisms on each mineral surface was quantified. The 16S rRNA of attached microbial communities were compared using Roche FLX and Titanium 454 next generation pyrosequencing. A primary controlling factor on taxonomy of attached microorganisms in both pure and mixed culture experiments was mineral buffering capacity. In mixed culture experiments acid-buffering carbonates were preferentially colonized by neutrophilic sulfur-oxidizing microorganisms (~18% to ~27% of microorganisms), while acidophilic sulfur-oxidizing microorganisms colonized non-buffering quartz exclusively (~46% of microorganisms). The nutrient content of the rock was a controlling factor on biomass accumulation, with neutrophilic organisms selecting between carbonate surfaces of equivalent buffer capacities according to the availability of phosphate. Dry biomass on ML was 17.8 ± 2.3 mg/cm2 and MD was 20.6 ± 6.8 mg/cm2; while nutrient poor calcite accumulated 2.4 ± 0.3 mg/cm2. Biomass accumulation was minimal on non-buffering nutrient-limited surfaces. These factors are countered by the competitive exclusion of some populations. A pure culture of T. unzii preferentially colonizes carbonates while a very closely related Thiothrix spp is excluded

  15. Farm management, not soil microbial diversity, controls nutrient loss from smallholder tropical agriculture

    Directory of Open Access Journals (Sweden)

    Stephen A Wood

    2015-03-01

    Full Text Available Tropical smallholder agriculture supports the livelihoods of over 900 million of the world’s poorest people. This form of agriculture is undergoing rapid transformation in nutrient cycling pathways as international development efforts strongly promote greater use of mineral fertilizers to increase crop yields. These changes in nutrient availability may alter the composition of microbial communities with consequences for rates of biogeochemical processes that control nutrient losses to the environment. Ecological theory suggests that altered microbial diversity will strongly influence processes performed by relatively few microbial taxa, such as denitrification and hence nitrogen losses as nitrous oxide, a powerful greenhouse gas. Whether this theory helps predict nutrient losses from agriculture depends on the relative effects of microbial community change and increased nutrient availability on ecosystem processes. We find that mineral and organic nutrient addition to smallholder farms in Kenya alters the taxonomic and functional diversity of soil microbes. However, we find that the direct effects of farm management on both denitrification and carbon mineralization are greater than indirect effects through changes in the taxonomic and functional diversity of microbial communities. Changes in functional diversity are strongly coupled to changes in specific functional genes involved in denitrification, suggesting that it is the expression, rather than abundance, of key functional genes that can serve as an indicator of ecosystem process rates. Our results thus suggest that widely used broad summary statistics of microbial diversity based on DNA may be inappropriate for linking microbial communities to ecosystem processes in certain applied settings. Our results also raise doubts about the relative control of microbial composition compared to direct effects of management on nutrient losses in applied settings such as tropical agriculture.

  16. pH and Organic Carbon Dose Rates Control Microbially Driven Bioremediation Efficacy in Alkaline Bauxite Residue.

    Science.gov (United States)

    Santini, Talitha C; Malcolm, Laura I; Tyson, Gene W; Warren, Lesley A

    2016-10-18

    Bioremediation of alkaline tailings, based on fermentative microbial metabolisms, is a novel strategy for achieving rapid pH neutralization and thus improving environmental outcomes associated with mining and refining activities. Laboratory-scale bioreactors containing bauxite residue (an alkaline, saline tailings material generated as a byproduct of alumina refining), to which a diverse microbial inoculum was added, were used in this study to identify key factors (pH, salinity, organic carbon supply) controlling the rates and extent of microbially driven pH neutralization (bioremediation) in alkaline tailings. Initial tailings pH and organic carbon dose rates both significantly affected bioremediation extent and efficiency with lower minimum pHs and higher extents of pH neutralization occurring under low initial pH or high organic carbon conditions. Rates of pH neutralization (up to 0.13 mM H + produced per day with pH decreasing from 9.5 to ≤6.5 in three days) were significantly higher in low initial pH treatments. Representatives of the Bacillaceae and Enterobacteriaceae, which contain many known facultative anaerobes and fermenters, were identified as key contributors to 2,3-butanediol and/or mixed acid fermentation as the major mechanism(s) of pH neutralization. Initial pH and salinity significantly influenced microbial community successional trajectories, and microbial community structure was significantly related to markers of fermentation activity. This study provides the first experimental demonstration of bioremediation in bauxite residue, identifying pH and organic carbon dose rates as key controls on bioremediation efficacy, and will enable future development of bioreactor technologies at full field scale.

  17. Control of GHG emission at the microbial community level.

    Science.gov (United States)

    Insam, H; Wett, B

    2008-01-01

    All organic material eventually is decomposed by microorganisms, and considerable amounts of C and N end up as gaseous metabolites. The emissions of greenhouse relevant gases like carbon dioxide, methane and nitrous oxides largely depend on physico-chemical conditions like substrate quality or the redox potential of the habitat. Manipulating these conditions has a great potential for reducing greenhouse gas emissions. Such options are known from farm and waste management, as well as from wastewater treatment. In this paper examples are given how greenhouse gas production might be reduced by regulating microbial processes. Biogas production from manure, organic wastes, and landfills are given as examples how methanisation may be used to save fossil fuel. Methane oxidation, on the other hand, might alleviate the problem of methane already produced, or the conversion of aerobic wastewater treatment to anaerobic nitrogen elimination through the anaerobic ammonium oxidation process might reduce N2O release to the atmosphere. Changing the diet of ruminants, altering soil water potentials or a change of waste collection systems are other measures that affect microbial activities and that might contribute to a reduction of carbon dioxide equivalents being emitted to the atmosphere.

  18. Mineralogical controls on microbial biomass accumulation on two tropical soils

    Science.gov (United States)

    Block, K. A.; Pena, S. A.; Katz, A.; Gottlieb, P.; Volta, A.

    2017-12-01

    The characteristics of soil organic matter (SOM) generated by microbes and associated with minerals are not well defined. This information is critical to reducing uncertainty in climate models related to C cycling and ecosystem feedbacks. The resistance to degradation of mineral-associated SOM is influenced by aggregate structure, mineral chemistry and microbial community. In this work we examine the influence of mineral composition, including amorphous coatings on the biomass yield and aggregate structure through thermogravimetric analysis, X-ray diffraction and electron microscopy. Two soil organisms, Pseudomonas phaseolicola, and Streptomyces griseosporus, were each incubated over a 72-hour period in minimal media with the cultured under the same conditions. In all samples, approximately half of the sample mass loss occurred between 175 ºC - 375 ºC, which we attribute to biomolecules accumulated on the mineral surfaces. We observed a slightly larger mass loss in the Inceptisol than in the Oxisol, most of which corresponded to compounds that underwent pyrolysis at 300 ºC. HRTEM micrographs and TEM-EDS image maps showing the spatial relationship of microbial necromass to soil minerals will be reported.

  19. Exploitation of microbial antagonists for the control of postharvest diseases of fruits: a review.

    Science.gov (United States)

    Dukare, Ajinath Shridhar; Paul, Sangeeta; Nambi, V Eyarkai; Gupta, Ram Kishore; Singh, Rajbir; Sharma, Kalyani; Vishwakarma, Rajesh Kumar

    2018-01-16

    Fungal diseases result in significant losses of fruits and vegetables during handling, transportation and storage. At present, post-production fungal spoilage is predominantly controlled by using synthetic fungicides. Under the global climate change scenario and with the need for sustainable agriculture, biological control methods of fungal diseases, using antagonistic microorganisms, are emerging as ecofriendly alternatives to the use of fungicides. The potential of microbial antagonists, isolated from a diversity of natural habitats, for postharvest disease suppression has been investigated. Postharvest biocontrol systems involve tripartite interaction between microbial antagonists, the pathogen and the host, affected by environmental conditions. Several modes for fungistatic activities of microbial antagonists have been suggested, including competition for nutrients and space, mycoparasitism, secretion of antifungal antibiotics and volatile metabolites and induction of host resistance. Postharvest application of microbial antagonists is more successful for efficient disease control in comparison to pre-harvest application. Attempts have also been made to improve the overall efficacy of antagonists by combining them with different physical and chemical substances and methods. Globally, many microbe-based biocontrol products have been developed and registered for commercial use. The present review provides a brief overview on the use of microbial antagonists as postharvest biocontrol agents and summarises information on their isolation, mechanisms of action, application methods, efficacy enhancement, product formulation and commercialisation.

  20. Functional characteristics and influence factors of microbial community in sewage sludge composting with inorganic bulking agent.

    Science.gov (United States)

    Wang, Ke; Mao, Hailong; Li, Xiangkun

    2018-02-01

    The metabolic function of microbial community dominated organics and nutrients transformation in aerobic composting process. In this study, the metabolic characteristics of bacterial and fungal communities were evaluated in 60 days composting of sludge and pumice by using FUNGuild and PICRUSt, respectively. The results showed that microbial community structure and metabolic characteristics were distinctively different at four composting periods. Bacterial genes related to carbohydrate metabolisms decreased during the first 30 days, but bacterial sequences associated with oxidative phosphorylation and fatty acids synthesis were enhanced in curing phase. Most of fungal animal pathogen and plant pathogen disappeared after treatment, and the abundance of saprotroph fungi increased from 44.3% to 97.8%. Oxidation reduction potential (ORP) significantly increased from -28 to 175 mV through incubation. RDA analysis showed that ORP was a crucial factor on the succession of both bacterial and fungal communities in sludge composting system. Copyright © 2017. Published by Elsevier Ltd.

  1. Microbial biopesticides for control of invertebrates: Progress from New Zealand.

    Science.gov (United States)

    Glare, Travis R; O'Callaghan, Maureen

    2017-11-28

    Biopesticides are needed for control of endemic and invasive pests impacting New Zealand's primary sectors including pests that are emerging as a result of climate change and farming intensification. Products developed in New Zealand are usually based on endemic strains of microorganisms, including new species/strains with novel modes of action. For example, Invade and BioShield were developed using endemic strains of the bacterium Serratia entomophila, for use in New Zealand only. To date, most of these home-grown products have either struggled for market share or have remained in small niche markets. However, the number of products registered for use has been steadily increasing in response to consumer demand. Factors limiting past use of biopesticides in New Zealand include market size, registration costs and limited efficacy over a range of climatic zones. Many promising new agents are currently under development as biopesticides with international applications and the launch of several new start-up companies suggests a brighter future for biopesticide use in New Zealand. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Strategies to diagnose and control microbial souring in natural gas storage reservoirs and produced water systems

    Energy Technology Data Exchange (ETDEWEB)

    Morris, E.A.; Derr, R.M.; Pope, D.H.

    1995-12-31

    Hydrogen sulfide production (souring) in natural gas storage reservoirs and produced water systems is a safety and environmental problem that can lead to operational shutdown when local hydrogen sulfide standards are exceeded. Systems affected by microbial souring have historically been treated using biocides that target the general microbial community. However, requirements for more environmentally friendly solutions have led to treatment strategies in which sulfide production can be controlled with minimal impact to the system and environment. Some of these strategies are based on microbial and/or nutritional augmentation of the sour environment. Through research sponsored by the Gas Research Institute (GRI) in Chicago, Illinois, methods have been developed for early detection of microbial souring in natural gas storage reservoirs, and a variety of mitigation strategies have been evaluated. The effectiveness of traditional biocide treatment in gas storage reservoirs was shown to depend heavily on the methods by which the chemical is applied. An innovative strategy using nitrate was tested and proved ideal for produced water and wastewater systems. Another strategy using elemental iodine was effective for sulfide control in evaporation ponds and is currently being tested in microbially sour natural gas storage wells.

  3. Biogeochemical Processes Controlling Microbial Reductive Precipitation of Radionuclides

    International Nuclear Information System (INIS)

    Fredrickson, James K.; Brooks, Scott C.

    2004-01-01

    This project is focused on elucidating the principal biogeochemical reactions that govern the concentrations, chemical speciation, and distribution of the redox sensitive contaminants uranium (U) and technetium (Tc) between the aqueous and solid phases. The research is designed to provide new insights into the under-explored areas of competing geochemical and microbiological oxidation-reduction reactions that govern the fate and transport of redox sensitive contaminants and to generate fundamental scientific understanding of the identity and stoichiometry of competing microbial reduction and geochemical oxidation reactions. These goals and objectives are met through a series of hypothesis-driven tasks that focus on (1) the use of well-characterized microorganisms and synthetic and natural mineral oxidants, (2) advanced spectroscopic and microscopic techniques to monitor redox transformations of U and Tc, and (3) the use of flow-through experiments to more closely approximate groundwater environments. The results are providing an improved understanding and predictive capability of the mechanisms that govern the redox dynamics of radionuclides in subsurface environments. For purposes of this poster, the results are divided into three sections: (1) influence of Ca on U(VI) bioreduction; (2) localization of biogenic UO 2 and TcO 2 ; and (3) reactivity of Mn(III/IV) oxides.

  4. Aschersonia aleyrodis as a microbial control agent of greenhouse whitefly

    NARCIS (Netherlands)

    Fransen, J.J.

    1987-01-01

    Various aspects of the development of the entomopathogenic fungus Aschersoniaaleyrodis as a control agent of greenhouse whitefly, Trialeurodesvaporariorum , were investigated. For control of greenhouse whitefly in tomato

  5. Environmental factors influencing the structural dynamics of soil microbial communities during assisted phytostabilization of acid-generating mine tailings: a mesocosm experiment.

    Science.gov (United States)

    Valentín-Vargas, Alexis; Root, Robert A; Neilson, Julia W; Chorover, Jon; Maier, Raina M

    2014-12-01

    Compost-assisted phytostabilization has recently emerged as a robust alternative for reclamation of metalliferous mine tailings. Previous studies suggest that root-associated microbes may be important for facilitating plant establishment on the tailings, yet little is known about the long-term dynamics of microbial communities during reclamation. A mechanistic understanding of microbial community dynamics in tailings ecosystems undergoing remediation is critical because these dynamics profoundly influence both the biogeochemical weathering of tailings and the sustainability of a plant cover. Here we monitor the dynamics of soil microbial communities (i.e. bacteria, fungi, archaea) during a 12-month mesocosm study that included 4 treatments: 2 unplanted controls (unamended and compost-amended tailings) and 2 compost-amended seeded tailings treatments. Bacterial, fungal and archaeal communities responded distinctively to the revegetation process and concurrent changes in environmental conditions and pore water chemistry. Compost addition significantly increased microbial diversity and had an immediate and relatively long-lasting buffering-effect on pH, allowing plants to germinate and thrive during the early stages of the experiment. However, the compost buffering capacity diminished after six months and acidification took over as the major factor affecting plant survival and microbial community structure. Immediate changes in bacterial communities were observed following plant establishment, whereas fungal communities showed a delayed response that apparently correlated with the pH decline. Fluctuations in cobalt pore water concentrations, in particular, had a significant effect on the structure of all three microbial groups, which may be linked to the role of cobalt in metal detoxification pathways. The present study represents, to our knowledge, the first documentation of the dynamics of the three major microbial groups during revegetation of compost

  6. Leveraging culture collections for the discovery and development of microbial biological control agents

    Science.gov (United States)

    The incorporation of living microbial biological control agents into integrated pest management programs is highly desirable because it reduces the use of chemical insecticides harmful to livestock, humans and the environment. In addition, it provides an alternative means to combat resistance to che...

  7. Effect of fixed orthodontic appliances on salivary microbial parameters at 6 months : a controlled observational study

    NARCIS (Netherlands)

    Maret, Delphine; Marchal-Sixou, Christine; Vergnes, Jean-Noel; Hamel, Olivier; Georgelin-Gurgel, Marie; Van Der Sluis, Lucas; Sixou, Michel

    2014-01-01

    Objective: The aim of this study was to assess the microbial changes in children with fixed orthodontic appliances compared with a control group of children without orthodontic treatment. Material and Methods: Ninety-five children, aged between 12 and 16 years, participated in this study.

  8. Effect of Nisin's Controlled Release on Microbial Growth as Modeled for Micrococcus luteus.

    Science.gov (United States)

    Balasubramanian, Aishwarya; Lee, Dong Sun; Chikindas, Michael L; Yam, Kit L

    2011-06-01

    The need for safe food products has motivated food scientists and industry to find novel technologies for antimicrobial delivery for improving food safety and quality. Controlled release packaging is a novel technology that uses the package to deliver antimicrobials in a controlled manner and sustain antimicrobial stress on the targeted microorganism over the required shelf life. This work studied the effect of controlled release of nisin to inhibit growth of Micrococcus luteus (a model microorganism) using a computerized syringe pump system to mimic the release of nisin from packaging films which was characterized by an initially fast rate and a slower rate as time progressed. The results show that controlled release of nisin was strikingly more effective than instantly added ("formulated") nisin. While instant addition experiments achieved microbial inhibition only at the beginning, controlled release experiments achieved complete microbial inhibition for a longer time, even when as little as 15% of the amount of nisin was used as compared to instant addition.

  9. MICROBIAL DIVERSITY AS A CONTROLLING FACTOR OF AEROBIC METHANE CONSUMPTION

    NARCIS (Netherlands)

    Bodelier, P.L.E.; Meima-Franke, M.; Hordijk, C.A.; Steenbergh, A.K.

    2010-01-01

    Background. Aerobic methane oxidizing bacteria (MOB) play a vital role in the global climate by degrading the greenhouse gas CH4. The process of CH4 consumption is sensitive to disturbance leading to strong variability in CH4 emission from ecosystems. Mechanistic explanations for variability in CH4

  10. Biomimicry of volatile-based microbial control for managing emerging fungal pathogens.

    Science.gov (United States)

    Gabriel, K T; Joseph Sexton, D; Cornelison, C T

    2018-05-01

    Volatile organic compounds (VOCs) are known to be produced by a wide range of micro-organisms and for a number of purposes. Volatile-based microbial inhibition in environments such as soil is well-founded, with numerous antimicrobial VOCs having been identified. Inhibitory VOCs are of interest as microbial control agents, as low concentrations of gaseous VOCs can elicit significant antimicrobial effects. Volatile organic compounds are organic chemicals typically characterized as having low molecular weight, low solubility in water, and high vapour pressure. Consequently, VOCs readily evaporate to the gaseous phase at standard temperature and pressure. This contact-independent antagonism presents unique advantages over traditional, contact-dependent microbial control methods, including increased surface exposure and reduced environmental persistence. This approach has been the focus of our recent research, with positive results suggesting it may be particularly promising for the management of emerging fungal pathogens, such as the causative agents of white-nose syndrome of bats and snake fungal disease, which are difficult or impossible to treat using traditional approaches. Here, we review the history of volatile-based microbial control, discuss recent progress in formulations that mimic naturally antagonistic VOCs, outline the development of a novel treatment device, and highlight areas where further work is needed to successfully deploy VOCs against existing and emerging fungal pathogens. © 2017 The Society for Applied Microbiology.

  11. Microbial contamination control in fuels and fuel systems since 1980 - a review

    Energy Technology Data Exchange (ETDEWEB)

    Passman, Frederick J. [Biodeterioration Control Associates, Inc (United States)], email: fredp@biodeterioration-control.com

    2011-07-01

    This paper presents a review of microbial contamination control in fuel and fuel systems. Some examples of the biodeterioration of components of fuel systems are given. Root cause analysis (RCA) and modeling can help in condition monitoring of fuel systems. RCA is a systematic process that starts after symptoms become apparent and facilitates improvement. Modeling, by contrast, starts before the problem occurs and the objective is to improve understanding of the process. Some of the different areas creating risk due to the process are climate, microbiology, chemistry, maintenance, and engineering. Condition monitoring is explained in detail, using representative samples. Contamination control plays a very important role. Various aspects of microbial contamination control are design, inventory control, house keeping and remediation. These aspects are explained in detail, using various examples. Since the deterioration cost involved is very high, its is important to avoid this problem by reducing the quantity of water used and using better risk assessment models.

  12. The influence of the microbial factor on the death of animals by intestinal radiation syndrome

    International Nuclear Information System (INIS)

    Kudryavtsev, V.D.; Kartasheva, A.L.; Tsyran, N.I.

    1979-01-01

    Data obtained in rats and mice irradiated with 900 - 1600 rad 60 Co gamma radiation point to an important role of the microbial factor in the 'intestinal death'. At the climax of the intestinal syndrome dysbacterial conditions developed violently in the intestinal content under predominance of putrefactive bacteria (Proteus). The application of kanamycin according to an elaborated pattern completely suppressed the proteus growth in the intestine and decreased considerably the content of obligatory representatives of the intestinal flora by which most of the animals could survive the time of 'intestinal death' (3rd to 5th day) after irradiation with relatively low doses (900 - 1200 rad). With increasing radiation doses (up to 1400 rad and more) the antibacterial therapy became uneffective because of the increasing importance of other lethal factors. The analysis of these results as well as literature data allow the conclusion that microbial intoxication plays a leading role in the death of the animals at the initial period and at the climax of the intestinal syndrome (3rd to 4th day). At the final stage of the development of the intestinal syndrome (5th day) septicaemia supervened. (author)

  13. Microbial profile and critical control points during processing of 'robo ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-05-18

    May 18, 2009 ... frying, surface fat draining, open-air cooling, and holding/packaging in polyethylene films during sales and distribution. The product was, however, classified under category III with respect to risk and the significance of monitoring and evaluation of quality using the hazard analysis critical control point.

  14. Microbial control of Asian longhorned beetles - what are fungal bands?

    Science.gov (United States)

    Ann E. Hajek; Thomas Dubois; Jennifer Lund; Ryan Shanley; Leah Bauer; Michael Smith; Peng Fan; Huang Bo; Hu Jiafu; Zengzhi Li

    2007-01-01

    In Japan, the entomopathogenic fungus Beauveria brongniartii is grown in nonwoven fiber bands that are placed around trunks of orchard trees for control of numerous cerambycid pests, including Anoplophora chinensis (= A. malasiaca). The Japanese company producing bands, Nitto Denko in Osaka, markets bands...

  15. THE ROLE OF BACTERIAL FACTOR AND IMMUNOLOGICAL СHANGES IN NONINFECTIOUS DISEASES OF MICROBIAL ORIGIN

    Directory of Open Access Journals (Sweden)

    Korniychuk O.P.

    2015-05-01

    lipopolysaccharide of own and intact E. coli and isolates from control persons. Results and discussion. LPS isolated from E. coli strains isolated from patients with different clinical groups showed varying effects on the immune response. It was established that cytokines are produced to stimulation by antigens of own microflora more active than by the intact lipopolysaccharide. Moreover, it is typical for both proinflammatory and problastomic cytokines. The highest activity was found in lipopolysaccharide bacteria isolated in patients with Crohn's disease, for the pathogenesis of which immunopathological component was proved and which can accordingly cause certain features of the disease. Trigger factors for developing reactive arthritis (ReA microorganisms with obligate (Chlamydia, some viruses or optional (Yersinia, Shigella, mycoplasma, Campylobacteria, salmonella parasitism are considered to be. Research of subpopulation spectrum of blood lymphocytes of 20 persons with ReA was conducted. Slight decrease in absolute quantity of natural killers was registered. Thus, the relative index CD16 + 56 + in patients with ReA was 11,8 ± 1,21% to 14,92 ± 1,13 in almost healthy individuals. However, some activation of suppressor affects the immune-regulatory index (IRI. Its amount is 1.74, which generally remains within normal limits, but is 21.8% lower than IRI of control group. Conclusion. Research of subpopulation composition of Tand B-chains of immunity at ReA to some extent confirm the theory of arthritogenic peptide of the disease development, according to which in the background of Tsuppressors activation, induced by microbial triggers, a weakening of cellular immunity occurs, inflammatory reactions with the emergence of autoimmune background develops, that in case of involving muscle and bone system leads to ReA development. In the acute stage of the disease with signs of inflammation it is appropriate to conduct antimicrobial therapy as with ReA and with diseases of the colon

  16. Automatic control of load increases power and efficiency in a microbial fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Premier, Giuliano C.; Kim, Jung Rae; Michie, Iain [Sustainable Environment Research Centre (SERC), Faculty of Advanced Technology, University of Glamorgan, Pontypridd, Mid-Glamorgan CF37 1DL (United Kingdom); Dinsdale, Richard M.; Guwy, Alan J. [Sustainable Environment Research Centre (SERC), Faculty of Health, Sport and Science, University of Glamorgan, Pontypridd, Mid-Glamorgan CF37 1DL (United Kingdom)

    2011-02-15

    Increasing power production and coulombic efficiency (CE) of microbial fuel cells (MFCs) is a common research ambition as the viability of the technology depends to some extent on these measures of performance. As MFCs are typically time varying systems, comparative studies of controlled and un-controlled external load impedance are needed to show if control affects the biocatalyst development and hence MFC performance. The application of logic based control of external load resistance is shown to increase the power generated by the MFC, when compared to an equivalent system which has a static resistive load. The controlled MFC generated 1600 {+-} 400 C, compared to 300 {+-} 10 C with an otherwise replicate fixed load MFC system. The use of a parsimonious gradient based control was able to increase the CE to within the range of 15.1-22.7%, while the CE for a 200 {omega} statically loaded MFC lay in the range 3.3-3.7%. The controlled MFC improves the electrogenic anodic biofilm selection for power production, indicating that greater power and substrate conversion can be achieved by controlling load impedance. Load control ensured sustainable current demand, applied microbial selection pressures and provided near-optimal impedance for power transference, compared to the un-controlled system. (author)

  17. Review of microbial responses to abiotic environmental factors in the context of the proposed Yucca Mountain repository

    Energy Technology Data Exchange (ETDEWEB)

    Meike, A [Lawrence Livermore National Lab., Livermore, CA (United States); Stroes-Gascoyne, S

    2000-10-01

    A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behaviour into performance assessment models. One effort was to expand an existing modelling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories, 1) abiotic factors, 2) community dynamics and in-situ considerations, 3) nutrient considerations and 4) transport of radionuclides. The complete bibliography (included in Appendix A) represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain. The first part of the report (Chapters 1-3) is a review of general microbial states, phases and requirements for growth, conditions for 'normal growth' and other types of growth, survival strategies and cell death. It contains primarily well-established ideas in microbiology. Microbial capabilities for survival and adaptation to environmental changes are examined because a repository placed at Yucca Mountain would have two effects. First, the natural environment would be perturbed by the excavation and construction of the repository and

  18. Review of microbial responses to abiotic environmental factors in the context of the proposed Yucca Mountain repository

    Energy Technology Data Exchange (ETDEWEB)

    Meike, A. [Lawrence Livermore National Lab., Livermore, CA (United States); Stroes-Gascoyne, S

    2000-10-01

    A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behaviour into performance assessment models. One effort was to expand an existing modelling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories, 1) abiotic factors, 2) community dynamics and in-situ considerations, 3) nutrient considerations and 4) transport of radionuclides. The complete bibliography (included in Appendix A) represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain. The first part of the report (Chapters 1-3) is a review of general microbial states, phases and requirements for growth, conditions for 'normal growth' and other types of growth, survival strategies and cell death. It contains primarily well-established ideas in microbiology. Microbial capabilities for survival and adaptation to environmental changes are examined because a repository placed at Yucca Mountain would have two effects. First, the natural environment would be perturbed by the excavation and construction of the

  19. Factors controlling metal fuel lifetime

    International Nuclear Information System (INIS)

    Porter, D.L.; Hofman, G.L.; Seidel, B.R.; Walters, L.C.

    1986-01-01

    The reliability of metal fuel elements is determined by a fuel burnup at which a statistically predicted number of fuel breaches would occur, the number of breaches determined by the amount of free fission gas which a particular reactor design can tolerate. The reliability is therefore measured using experimentally determined breach statistics, or by modelling fuel element behavior and those factors which contribute to cladding breach. The factors are fuel/cladding mechanical and chemical interactions, fission gas pressure, fuel phase transformations involving volume changes, and fission product effects on cladding integrity. Experimental data for EBR-II fuel elements has shown that the primary, and perhaps the only significant factor affecting metal fuel reliability, is the pressure-induced stresses caused by fission gas release. Other metal fuel/cladding systems may perform similarly

  20. Factors limiting microbial growth and activity at a proposed high-level nuclear repository, Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Kieft, T.L.; Kovacik, W.P. Jr.; Ringelberg, D.B.; White, D.C.; Haldeman, D.L.; Amy, P.S.; Hersman, L.E.

    1997-01-01

    As part of the characterization of Yucca Mountain, Nev., as a potential repository for high-level nuclear waste, volcanic tuff was analyzed for microbial abundance and activity. Tuff was collected aseptically from nine sites along a tunnel in Yucca Mountain. Microbial abundance was generally low: direct microscopic cell counts were near detection limits at all sites (3.2 X 10(1) to 2.0 X 10(5) cells g-1 [dry weight]); plate counts of aerobic heterotrophs ranged from 1.0 X 10(1) to 3.2 X 10(3) CFU g-1 (dry weight). Phospholipid fatty acid concentrations (0.1 to 3.7 pmol g-1) also indicated low microbial biomasses: diglyceride fatty acid concentrations, indicative of dead cells, were in a similar range (0.2 to 2.3 pmol g-1). Potential microbial activity was quantified as 14CO2 production in microcosms containing radiolabeled substrates (glucose, acetate, and glutamic acid); amendments with water and nutrient solutions (N and P) were used to test factors potentially limiting this activity. Similarly, the potential for microbial growth and the factors limiting growth were determined by performing plate counts before and after incubating volcanic tuff samples for 24 h under various conditions: ambient moisture, water-amended, and amended with various nutrient solutions (N, P, and organic C). A high potential for microbial activity was demonstrated by high rates of substrate mineralization (as much as 70% of added organic C in 3 weeks). Water was the major limiting factor to growth and microbial activity, while amendments with N and P resulted in little further stimulation. Organic C amendments stimulated growth more than water alone

  1. Current knowledge on groundwater microbial pathogens and their control

    Science.gov (United States)

    Macler, Bruce A.; Merkle, Jon C.

    Those who drink groundwater that has not been disinfected are at increased risk of infection and disease from pathogenic microorganisms. Recent studies have shown that up to half of all US drinking-water wells tested had evidence of fecal contamination. A significant fraction of all waterborne disease outbreaks is associated with groundwater. An estimated 750,000 to 5.9million illnesses per year result from contaminated groundwaters in the US. Mortality from these illnesses may be 1400-9400 deaths per year. Control of these pathogens starts with source-water protection activities to prevent fecal contamination of aquifers and wells. These include assessment of wellhead vulnerability to fecal contamination and correction of identified deficiencies. Correction may include control of sources or rehabilitation of the well itself. Disinfection can serve as a useful barrier and is recommended as a prudent public-health policy for all groundwater systems. Ceux qui boivent une eau souterraine non désinfectée présentent un risque accru d'infection et de maladie par des germes pathogènes. De récentes études ont montré que près de la moitié de tous les puits américains testés, captés pour l'eau potable, sont soumis à une contamination fécale. Une fraction significative de l'ensemble des premières manifestations de maladies liées à l'eau est associée aux eaux souterraines. On estime qu'entre 750 000 et 5,9millions de personnes sont malades chaque année aux États-Unis à cause d'eaux souterraines polluées. La mortalité parmi ces malades doit ètre de l'ordre de 1400 à 9400 décès par an. La protection contre ces germes pathogènes commence avec des mesures prises au niveau du captage pour empècher la pollution des aquifères et des puits. Celles-ci comprennent une évaluation de la vulnérabilité des tètes de puits à la pollution fécale et une correction des insuffisances mises en évidence. Cette correction peut comprendre une maîtrise des sources

  2. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

    International Nuclear Information System (INIS)

    Joel E. Kostka; Lainie Petrie; Nadia North; David L. Balkwill; Joseph W. Stucki; Lee Kerkhof

    2004-01-01

    The overall objective of our project is to understand the microbial and geochemical mechanisms controlling the reduction and immobilization of U(VI) during biostimulation in subsurface sediments of the Field Research Center (FRC) which are cocontaminated with uranium and nitrate. The focus will be on activity of microbial populations (metal- and nitrate-reducing bacteria) and iron minerals which are likely to make strong contributions to the fate of uranium during in situ bioremediation. The project will: (1) quantify the relationships between active members of the microbial communities, iron mineralogy, and nitrogen transformations in the field and in laboratory incubations under a variety of biostimulation conditions, (2) purify and physiologically characterize new model metal-reducing bacteria isolated from moderately acidophilic FRC subsurface sediments, and (3) elucidate the biotic and abiotic mechanisms by which FRC aluminosilicate clay minerals are reduced and dissolved under environmental conditions resembling those during biostimulation. Active microbial communities will be assessed using quantitative molecular techniques along with geochemical measurements to determine the different terminal-electron-accepting pathways. Iron minerals will be characterized using a suite of physical, spectroscopic, and wet chemical methods. Monitoring the activity and composition of the denitrifier community in parallel with denitrification intermediates during nitrate removal will provide a better understanding of the indirect effects of nitrate reduction on uranium speciation. Through quantification of the activity of specific microbial populations and an in-depth characterization of Fe minerals likely to catalyze U sorption/precipitation, we will provide important inputs for reaction-based biogeochemical models which will provide the basis for development of in situ U bioremediation strategies. In collaboration with Jack Istok and Lee Krumholz, we have begun to study the

  3. Biological stability of drinking water: controlling factors, methods and challenges

    Directory of Open Access Journals (Sweden)

    Emmanuelle ePrest

    2016-02-01

    Full Text Available Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g. development of opportunistic pathogens, aesthetic (e.g. deterioration of taste, odour, colour or operational (e.g. fouling or biocorrosion of pipes problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors such as (i type and concentration of available organic and inorganic nutrients, (ii type and concentration of residual disinfectant, (iii presence of predators such as protozoa and invertebrates, (iv environmental conditions such as water temperature, and (v spatial location of microorganisms (bulk water, sediment or biofilm. Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i existing knowledge on biological stability controlling factors and (ii how these factors are affected by drinking water production and distribution conditions. In addition, (iii the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discuss how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to

  4. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    Science.gov (United States)

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  5. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    KAUST Repository

    Prest, Emmanuelle I.

    2016-02-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and can lead to hygienic (e.g., development of opportunistic pathogens), aesthetic (e.g., deterioration of taste, odor, color) or operational (e.g., fouling or biocorrosion of pipes) problems. Drinking water contains diverse microorganisms competing for limited available nutrients for growth. Bacterial growth and interactions are regulated by factors, such as (i) type and concentration of available organic and inorganic nutrients, (ii) type and concentration of residual disinfectant, (iii) presence of predators, such as protozoa and invertebrates, (iv) environmental conditions, such as water temperature, and (v) spatial location of microorganisms (bulk water, sediment, or biofilm). Water treatment and distribution conditions in water mains and premise plumbing affect each of these factors and shape bacterial community characteristics (abundance, composition, viability) in distribution systems. Improved understanding of bacterial interactions in distribution systems and of environmental conditions impact is needed for better control of bacterial communities during drinking water production and distribution. This article reviews (i) existing knowledge on biological stability controlling factors and (ii) how these factors are affected by drinking water production and distribution conditions. In addition, (iii) the concept of biological stability is discussed in light of experience with well-established and new analytical methods, enabling high throughput analysis and in-depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order

  6. Microbial control on decomposition of radionuclides-containing oily waste in soil

    Science.gov (United States)

    Selivanovskaya, Svetlana; Galitskaya, Polina

    2014-05-01

    The oily wastes are formed annually during extraction, refinement, and transportation of the oil and may cause pollution of the environment. These wastes contain different concentrations of waste oil (40-60%), waste water (30-90%), and mineral particles (5-40%). Some oily wastes also contain naturally occurring radionuclides which were incorporated by water that was pumped up with the oil. For assessment of the hazard level of waste treated soil, not only measurements of contaminants content are needed, because bioavailability of oily components varies with hydrocarbon type, and soil properties. As far as namely microbial communities control the decomposition of organic contaminants, biological indicators have become increasingly important in hazard assessment and the efficiency of remediation process. In this study the decomposition of radionuclides-containing oily waste by soil microbial communities were estimated. Waste samples collected at the Tikchonovskii petroleum production yard (Tatarstan, Russia) were mixed with Haplic greyzem soil at ratio 1:4 and incubated for 120 days. During incubation period, the total hydrocarbon content of the soil mixed with the waste reduced from 156 ± 48 g kg-1 to 54 ± 8 g kg-1 of soil. The concentrations of 226Ra and 232Th were found to be 643 ± 127, 254 ± 56 Bq kg-1 and not changed significantly during incubation. Waste application led to a soil microbial biomass carbon decrease in comparison to control (1.9 times after 1 day and 1.3 times after 120 days of incubation). Microbial respiration increased in the first month of incubation (up to 120% and 160% of control after 1 and 30 days, correspondingly) and decreased to the end of incubation period (74% of control after 120 days). Structure of bacterial community in soil and soil/waste mixture was estimated after 120 days of incubation using SSCP method. The band number decreased in contaminated soil in comparison to untreated soil. Besides, several new dominant DNA

  7. A finely tuned symphony of factors modulates the microbial food web of a freshwater reservoir in spring

    Czech Academy of Sciences Publication Activity Database

    Šimek, Karel; Nedoma, Jiří; Znachor, Petr; Kasalický, Vojtěch; Jezbera, Jan; Horňák, Karel; Seďa, Jaromír

    2014-01-01

    Roč. 59, č. 5 (2014), s. 1477-1492 ISSN 0024-3590 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : microbial food web * freshwater reservoir * limnology Subject RIV: EE - Microbiology, Virology Impact factor: 3.794, year: 2014

  8. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2004-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report is performed jointly by, Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures and the work done on recovery experiments on core rocks. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results do not show a

  9. Physical Factors Correlate to Microbial Community Structure and Nitrogen Cycling Gene Abundance in a Nitrate Fed Eutrophic Lagoon.

    Science.gov (United States)

    Highton, Matthew P; Roosa, Stéphanie; Crawshaw, Josie; Schallenberg, Marc; Morales, Sergio E

    2016-01-01

    Nitrogenous run-off from farmed pastures contributes to the eutrophication of Lake Ellesmere, a large shallow lagoon/lake on the east coast of New Zealand. Tributaries periodically deliver high loads of nitrate to the lake which likely affect microbial communities therein. We hypothesized that a nutrient gradient would form from the potential sources (tributaries) creating a disturbance resulting in changes in microbial community structure. To test this we first determined the existence of such a gradient but found only a weak nitrogen (TN) and phosphorous gradient (DRP). Changes in microbial communities were determined by measuring functional potential (quantification of nitrogen cycling genes via nifH , nirS , nosZI , and nosZII using qPCR), potential activity (via denitrification enzyme activity), as well as using changes in total community (via 16S rRNA gene amplicon sequencing). Our results demonstrated that changes in microbial communities at a phylogenetic (relative abundance) and functional level (proportion of the microbial community carrying nifH and nosZI genes) were most strongly associated with physical gradients (e.g., lake depth, sediment grain size, sediment porosity) and not nutrient concentrations. Low nitrate influx at the time of sampling is proposed as a factor contributing to the observed patterns.

  10. Physical factors correlate to microbial community structure and nitrogen cycling gene abundance in a nitrate fed eutrophic lagoon

    Directory of Open Access Journals (Sweden)

    Matthew Paul Highton

    2016-10-01

    Full Text Available Nitrogenous run-off from farmed pastures contributes to the eutrophication of Lake Ellesmere, a large shallow lagoon/lake on the east coast of New Zealand. Tributaries periodically deliver high loads of nitrate to the lake which likely affect microbial communities therein. We hypothesized that a nutrient gradient would form from the potential sources (tributaries creating a disturbance resulting in changes in microbial community structure. To test this we first determined the existence of such a gradient but found only a weak nitrogen (TN and phosphorous gradient (DRP. Changes in microbial communities were determined by measuring functional potential (quantification of nitrogen cycling genes via nifH, nirS, nosZI and nosZII using qPCR, potential activity (via denitrification enzyme activity, as well as using changes in total community (via 16S rRNA gene amplicon sequencing. Our results demonstrated that changes in microbial communities at a phylogenetic (relative abundance and functional level (proportion of the microbial community carrying nifH and nosZI genes were most strongly associated with physical gradients (e.g. lake depth, sediment grain size, sediment porosity and not nutrient concentrations. Low nitrate influx at the time of sampling is proposed as a factor contributing to the observed patterns.

  11. Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

    International Nuclear Information System (INIS)

    Meike, A.; Stroes-Gascoyne, S.

    2000-01-01

    A workshop on Microbial Activities at Yucca Mountain (May 1995, Lafayette, CA) was held with the intention to compile information on all pertinent aspects of microbial activity for application to a potential repository at Yucca Mountain. The findings of this workshop set off a number of efforts intended to eventually incorporate the impacts of microbial behavior into performance assessment models. One effort was to expand an existing modeling approach to include the distinctive characteristics of a repository at Yucca Mountain (e.g., unsaturated conditions and a significant thermal load). At the same time, a number of experimental studies were initiated as well as a compilation of relevant literature to more thoroughly study the physical, chemical and biological parameters that would affect microbial activity under Yucca Mountain-like conditions. This literature search (completed in 1996) is the subject of the present document. The collected literature can be divided into four categories: (1) abiotic factors, (2) community dynamics and in-situ considerations, (3) nutrient considerations and (4) transport of radionuclides. The complete bibliography represents a considerable resource, but is too large to be discussed in one document. Therefore, the present report focuses on the first category, abiotic factors, and a discussion of these factors in order to facilitate the development of a model for Yucca Mountain

  12. Effect of a temperature gradient on Sphagnum fallax and its associated living microbial communities: a study under controlled conditions.

    Science.gov (United States)

    Jassey, Vincent E J; Gilbert, Daniel; Binet, Philippe; Toussaint, Marie-Laure; Chiapusio, Geneviève

    2011-03-01

    Microbial communities living in Sphagnum are known to constitute early indicators of ecosystem disturbances, but little is known about their response (including their trophic relationships) to climate change. A microcosm experiment was designed to test the effects of a temperature gradient (15, 20, and 25°C) on microbial communities including different trophic groups (primary producers, decomposers, and unicellular predators) in Sphagnum segments (0-3 cm and 3-6 cm of the capitulum). Relationships between microbial communities and abiotic factors (pH, conductivity, temperature, and polyphenols) were also studied. The density and the biomass of testate amoebae in Sphagnum upper segments increased and their community structure changed in heated treatments. The biomass of testate amoebae was linked to the biomass of bacteria and to the total biomass of other groups added and, thus, suggests that indirect effects on the food web structure occurred. Redundancy analysis revealed that microbial assemblages differed strongly in Sphagnum upper segments along a temperature gradient in relation to abiotic factors. The sensitivity of these assemblages made them interesting indicators of climate change. Phenolic compounds represented an important explicative factor in microbial assemblages and outlined the potential direct and (or) indirect effects of phenolics on microbial communities.

  13. Graphite anode surface modification with controlled reduction of specific aryl diazonium salts for improved microbial fuel cells power output.

    Science.gov (United States)

    Picot, Matthieu; Lapinsonnière, Laure; Rothballer, Michael; Barrière, Frédéric

    2011-10-15

    Graphite electrodes were modified with reduction of aryl diazonium salts and implemented as anodes in microbial fuel cells. First, reduction of 4-aminophenyl diazonium is considered using increased coulombic charge density from 16.5 to 200 mC/cm(2). This procedure introduced aryl amine functionalities at the surface which are neutral at neutral pH. These electrodes were implemented as anodes in "H" type microbial fuel cells inoculated with waste water, acetate as the substrate and using ferricyanide reduction at the cathode and a 1000 Ω external resistance. When the microbial anode had developed, the performances of the microbial fuel cells were measured under acetate saturation conditions and compared with those of control microbial fuel cells having an unmodified graphite anode. We found that the maximum power density of microbial fuel cell first increased as a function of the extent of modification, reaching an optimum after which it decreased for higher degree of surface modification, becoming even less performing than the control microbial fuel cell. Then, the effect of the introduction of charged groups at the surface was investigated at a low degree of surface modification. It was found that negatively charged groups at the surface (carboxylate) decreased microbial fuel cell power output while the introduction of positively charged groups doubled the power output. Scanning electron microscopy revealed that the microbial anode modified with positively charged groups was covered by a dense and homogeneous biofilm. Fluorescence in situ hybridization analyses showed that this biofilm consisted to a large extent of bacteria from the known electroactive Geobacter genus. In summary, the extent of modification of the anode was found to be critical for the microbial fuel cell performance. The nature of the chemical group introduced at the electrode surface was also found to significantly affect the performance of the microbial fuel cells. The method used for

  14. Human factors challenges for advanced process control

    International Nuclear Information System (INIS)

    Stubler, W.F.; O'Hara, J..M.

    1996-01-01

    New human-system interface technologies provide opportunities for improving operator and plant performance. However, if these technologies are not properly implemented, they may introduce new challenges to performance and safety. This paper reports the results from a survey of human factors considerations that arise in the implementation of advanced human-system interface technologies in process control and other complex systems. General trends were identified for several areas based on a review of technical literature and a combination of interviews and site visits with process control organizations. Human factors considerations are discussed for two of these areas, automation and controls

  15. Is the mineralisation response to root exudation controlled by the microbial stoichiometric demand in subarctic soils?

    Science.gov (United States)

    Rousk, Johannes; Hicks, Lettice; Leizeaga, Ainara; Michelsen, Anders; Rousk, Kathrin

    2017-04-01

    Climate change will expose arctic and subarctic systems to warming and a shift towards plant communities with more rhizosphere labile C input. Labile C can also increase the rate of loss of native soil organic matter (SOM); a phenomenon termed 'priming'. We investigated how warming (+1.1˚ C over ambient using open top chambers) and the addition of plant litter (90 g m-2 y-1) or organic nitrogen (N) (fungal fruit bodies; 90 g m-2 y-1) in the Subarctic influenced the susceptibility of SOM mineralisation to priming, and its microbial underpinnings. Root exudation were simulated with the addition of labile organic matter both in the form of only labile C (13C-glucose) or in the form of labile C and N (13C-alanine). We hypothesized that labile C would induce a higher mineralization of N than C sourced from SOM ("N mining"); a response unrelated to microbial growth responses. We also hypothesized that the N mining effect would be more pronounced in climate change simulation treatments of higher C/N (plant litter) than treatments with lower C/N (fungal fruitbodies and warming), with the control treatments intermediate. We also hypothesized that the addition of labile C and N would not result in selective N mining, but instead coupled responses of C and N mineralisation sourced from SOM; a response that would coincide with stimulated microbial growth responses. Labile C appeared to inhibit the mineralisation of C from SOM by up to 60% within hours. In contrast, the mineralisation of N from SOM was stimulated by up to 300%. These responses occurred rapidly and were unrelated to microbial successional dynamics, suggesting catabolic responses. Considered separately, the labile-C inhibited C mineralisation is compatible with previously reported findings termed 'preferential substrate utilisation' or 'negative apparent priming', while the stimulated N mineralisation responses echo recent reports of 'real priming' of SOM mineralisation. However, C and N mineralisation responses

  16. Hype or opportunity? Using microbial symbionts in novel strategies for insect pest control.

    Science.gov (United States)

    Arora, Arinder K; Douglas, Angela E

    2017-11-01

    All insects, including pest species, are colonized by microorganisms, variously located in the gut and within insect tissues. Manipulation of these microbial partners can reduce the pest status of insects, either by modifying insect traits (e.g. altering the host range or tolerance of abiotic conditions, reducing insect competence to vector disease agents) or by reducing fitness. Strategies utilizing heterologous microorganisms (i.e. derived from different insect species) and genetically-modified microbial symbionts are under development, particularly in relation to insect vectors of human disease agents. There is also the potential to target microorganisms absolutely required by the insect, resulting in insect mortality or suppression of insect growth or fecundity. This latter approach is particularly valuable for insect pests that depend on nutrients from symbiotic microorganisms to supplement their nutritionally-inadequate diet, e.g. insects feeding through the life cycle on vertebrate blood (cimicid bugs, anopluran lice, tsetse flies), plant sap (whiteflies, aphids, psyllids, planthoppers, leafhoppers/sharpshooters) and sound wood (various xylophagous beetles and some termites). Further research will facilitate implementation of these novel insect pest control strategies, particularly to ensure specificity of control agents to the pest insect without dissemination of bio-active compounds, novel microorganisms or their genes into the wider environment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. COMBINED MICROBIAL SURFACTANT-POLYMER SYSTEM FOR IMPROVED OIL MOBILITY AND CONFORMANCE CONTROL

    Energy Technology Data Exchange (ETDEWEB)

    Jorge Gabitto; Maria Barrufet

    2005-08-01

    Many domestic oil fields are facing abandonment even though they still contain two-thirds of their original oil. A significant number of these fields can yield additional oil using advanced oil recovery (AOR) technologies. To maintain domestic oil production at current levels, AOR technologies are needed that are affordable and can be implemented by the independent oil producers of the future. Microbial enhanced oil recovery (MEOR) technologies have become established as cost-effective solutions for declining oil production. MEOR technologies are affordable for independent producers operating stripper wells and can be used to extend the life of marginal fields. The demonstrated versatility of microorganisms can be used to design advanced microbial systems to treat multiple production problems in complex, heterogeneous reservoirs. The proposed research presents the concept of a combined microbial surfactant-polymer system for advanced oil recovery. The surfactant-polymer system utilizes bacteria that are capable of both biosurfactant production and metabolically-controlled biopolymer production. This novel technology combines complementary mechanisms to extend the life of marginal fields and is applicable to a large number of domestic reservoirs. The research project described in this report was performed by Bio-Engineering Inc., a woman owned small business, Texas A&M University and Prairie View A&M University, a Historically Black College and University. This report describes the results of our laboratory work to grow microbial cultures, the work done on recovery experiments on core rocks, and computer simulations. We have selected two bacterial strains capable of producing both surfactant and polymers. We have conducted laboratory experiments to determine under what conditions surfactants and polymers can be produced from one single strain. We have conduct recovery experiments to determine the performance of these strains under different conditions. Our results

  18. Analyses of the influencing factors of soil microbial functional gene diversity in tropical rainforest based on GeoChip 5.0.

    Science.gov (United States)

    Cong, Jing; Liu, Xueduan; Lu, Hui; Xu, Han; Li, Yide; Deng, Ye; Li, Diqiang; Zhang, Yuguang

    2015-09-01

    To examine soil microbial functional gene diversity and causative factors in tropical rainforests, we used a microarray-based metagenomic tool named GeoChip 5.0 to profile it. We found that high microbial functional gene diversity and different soil microbial metabolic potential for biogeochemical processes were considered to exist in tropical rainforest. Soil available nitrogen was the most associated with soil microbial functional gene structure. Here, we mainly describe the experiment design, the data processing, and soil biogeochemical analyses attached to the study in details, which could be published on BMC microbiology Journal in 2015, whose raw data have been deposited in NCBI's Gene Expression Omnibus (accession number GSE69171).

  19. COMPOSITION AND METHOD FOR CONTROLLING MICROBIAL ADHESION AND BIOFILM FORMATION OF SURFACES

    DEFF Research Database (Denmark)

    2003-01-01

    The present invention describes how coating of surfaces with an extract, particularly a fish extract, can significantly reduce microbial adhesion, attachment, colonization and biofilm formation on surfaces. Such reduction of microbial adherence, attachment and colonization will be applicable...

  20. Direct evidence for microbial-derived soil organic matter formation and its ecophysiological controls

    Science.gov (United States)

    Kallenbach, Cynthia M.; Frey, Serita D.; Grandy, A. Stuart

    2016-11-01

    Soil organic matter (SOM) and the carbon and nutrients therein drive fundamental submicron- to global-scale biogeochemical processes and influence carbon-climate feedbacks. Consensus is emerging that microbial materials are an important constituent of stable SOM, and new conceptual and quantitative SOM models are rapidly incorporating this view. However, direct evidence demonstrating that microbial residues account for the chemistry, stability and abundance of SOM is still lacking. Further, emerging models emphasize the stabilization of microbial-derived SOM by abiotic mechanisms, while the effects of microbial physiology on microbial residue production remain unclear. Here we provide the first direct evidence that soil microbes produce chemically diverse, stable SOM. We show that SOM accumulation is driven by distinct microbial communities more so than clay mineralogy, where microbial-derived SOM accumulation is greatest in soils with higher fungal abundances and more efficient microbial biomass production.

  1. Humboldt's spa: microbial diversity is controlled by temperature in geothermal environments.

    Science.gov (United States)

    Sharp, Christine E; Brady, Allyson L; Sharp, Glen H; Grasby, Stephen E; Stott, Matthew B; Dunfield, Peter F

    2014-06-01

    Over 200 years ago Alexander von Humboldt (1808) observed that plant and animal diversity peaks at tropical latitudes and decreases toward the poles, a trend he attributed to more favorable temperatures in the tropics. Studies to date suggest that this temperature-diversity gradient is weak or nonexistent for Bacteria and Archaea. To test the impacts of temperature as well as pH on bacterial and archaeal diversity, we performed pyrotag sequencing of 16S rRNA genes retrieved from 165 soil, sediment and biomat samples of 36 geothermal areas in Canada and New Zealand, covering a temperature range of 7.5-99 °C and a pH range of 1.8-9.0. This represents the widest ranges of temperature and pH yet examined in a single microbial diversity study. Species richness and diversity indices were strongly correlated to temperature, with R(2) values up to 0.62 for neutral-alkaline springs. The distributions were unimodal, with peak diversity at 24 °C and decreasing diversity at higher and lower temperature extremes. There was also a significant pH effect on diversity; however, in contrast to previous studies of soil microbial diversity, pH explained less of the variability (13-20%) than temperature in the geothermal samples. No correlation was observed between diversity values and latitude from the equator, and we therefore infer a direct temperature effect in our data set. These results demonstrate that temperature exerts a strong control on microbial diversity when considered over most of the temperature range within which life is possible.

  2. Controls upon microbial accessibility to soil organic matter following woody plant encroachment into grasslands

    Science.gov (United States)

    Creamer, C. A.; Boutton, T. W.; Filley, T. R.

    2009-12-01

    Woody plant encroachment (WPE) into savannas and grasslands is a global phenomenon that alters soil organic matter (SOM) dynamics through changes in litter quality and quantity, soil structure, microbial ecology, and soil hydrology. To elucidate the controls upon microbial accessibility to SOM, bulk soils from a chronosequence of progressive WPE into native grasslands at the Texas A&M Agricultural Experimental Station La Copita Research Area were incubated for one year. The quantity and stable carbon isotope composition of respired CO2, plant biopolymer chemistry in SOM, and microbial community structure were tracked. Respiration rates declined steadily over the course of the experiment with 15-25% of the total CO2 respired released in the first month of incubation. Between 8 and 18% of the total carbon was mineralized to CO2 throughout the incubation. After day 84 a significantly (p evidence of enhanced carbon stabilization in these respiration experiments. In fact, a greater proportion of total carbon was lost from the soil of mature woody stands than from young stands, suggesting carbon accumulation observed with WPE may be due to greater input rates or microbial dynamics not captured in the laboratory incubation. A cluster approximately 34 years in age represents a transition point in WPE where respiration dynamics become distinct between grassland and wooded elements. By day 84 of the incubation CO2 respired from all soils was depleted with respect to bulk SOM (1.5 to 5‰) and this pattern remained for the rest of the incubation. As the depletion of CO2 relative to bulk SOM was observed in grassland and cluster soils, we hypothesized the depleted signature resulted from the utilization of depleted biopolymers, specifically lignin, cutin and suberin, as hypothesized by others. Quantitative and isotopic comparisons of these monomers prior to and following the incubation will determine if selective compound utilization is a reason for this depletion. The results

  3. Effect of fixed orthodontic appliances on salivary microbial parameters at 6 months: a controlled observational study

    Directory of Open Access Journals (Sweden)

    Delphine MARET

    2014-01-01

    Full Text Available Objective: The aim of this study was to assess the microbial changes in children with fixed orthodontic appliances compared with a control group of children without orthodontic treatment. Material and Methods: Ninety-five children, aged between 12 and 16 years, participated in this study. Forty-eight subjects were fitted with fixed orthodontic appliances and forty-seven were free of any such appliances. The follow-up was 6 months for all children. The association between orthodontic appliances and high levels of Streptococcus mutans and Lactobacillus spp was assessed with logistic regression models, taking age, sex, pH and buffer capacity into account. Results: Differences at baseline between the two groups were not statistically significant. We found that wearing a fixed orthodontic appliance was associated with high levels of Streptococcus mutans and Lactobacillus spp (adjusted OR: 6.65, 95% CI [1.98-22.37]; 9.49, 95% CI [2.57-35.07], respectively, independently of other variables. Conclusion: The originality of the present epidemiological study was to evaluate the evolution of salivary microbial parameters in a population of children with fixed orthodontic appliances. Our results show an increase of Streptococcus mutans and Lactobacillus spp values during the follow-up. The whole dental workforce should be aware that preventive measures are of paramount importance during orthodontic treatment.

  4. Nanotechnology-based drug delivery systems for control of microbial biofilms: a review.

    Science.gov (United States)

    Dos Santos Ramos, Matheus Aparecido; Da Silva, Patrícia Bento; Spósito, Larissa; De Toledo, Luciani Gaspar; Bonifácio, Bruna Vidal; Rodero, Camila Fernanda; Dos Santos, Karen Cristina; Chorilli, Marlus; Bauab, Taís Maria

    2018-01-01

    Since the dawn of civilization, it has been understood that pathogenic microorganisms cause infectious conditions in humans, which at times, may prove fatal. Among the different virulent properties of microorganisms is their ability to form biofilms, which has been directly related to the development of chronic infections with increased disease severity. A problem in the elimination of such complex structures (biofilms) is resistance to the drugs that are currently used in clinical practice, and therefore, it becomes imperative to search for new compounds that have anti-biofilm activity. In this context, nanotechnology provides secure platforms for targeted delivery of drugs to treat numerous microbial infections that are caused by biofilms. Among the many applications of such nanotechnology-based drug delivery systems is their ability to enhance the bioactive potential of therapeutic agents. The present study reports the use of important nanoparticles, such as liposomes, microemulsions, cyclodextrins, solid lipid nanoparticles, polymeric nanoparticles, and metallic nanoparticles, in controlling microbial biofilms by targeted drug delivery. Such utilization of these nanosystems has led to a better understanding of their applications and their role in combating biofilms.

  5. EVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Bill W. Bogan; Wendy R. Sullivan; Kristine M. H. Cruz; Kristine L. Lowe; John J. Kilbane II

    2004-04-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing of pepper extracts resulted in preliminary data indicating that some pepper extracts inhibit the growth of some corrosion-associated microorganisms. This quarter additional tests were performed to more specifically investigate the ability of three pepper extracts to inhibit the growth, and to influence the metal corrosion caused by two microbial species: Desulfovibrio vulgaris, and Comomonas denitrificans. All three pepper extracts rapidly killed Desulfovibrio vulgaris, but did not appear to inhibit Comomonas denitrificans. While corrosion rates were at control levels in experiments with Desulfovibrio vulgaris that received pepper extract, corrosion rates were increased in the presence of Comomonas denitrificans plus pepper extract. Further testing with a wider range of pure bacterial cultures, and more importantly, with mixed bacterial cultures should be performed to determine the potential effectiveness of pepper extracts to inhibit MIC.

  6. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Bill W. Bogan; Brigid M. Lamb; John J. Kilbane II

    2004-10-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed to determine if chemical compounds other than pepper extracts could inhibit the growth of corrosion-associated microbes and to determine if pepper extracts and other compounds can inhibit corrosion when mature biofilms are present. Several chemical compounds were shown to be capable of inhibiting the growth of corrosion-associated microorganisms, and all of these compounds limited the amount of corrosion caused by mature biofilms to a similar extent. It is difficult to control corrosion caused by mature biofilms, but any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion.

  7. Biostimulation of Iron Reduction and Uranium Immobilization: Microbial and Mineralogical Controls

    International Nuclear Information System (INIS)

    Joel E. Kostka

    2008-01-01

    This project represented a joint effort between Florida State University (FSU), Rutgers University (RU), and the University of Illinois (U of I). FSU served as the lead institution and Dr. J.E. Kostka was responsible for project coordination, integration, and deliverables. This project was designed to elucidate the microbial ecology and geochemistry of metal reduction in subsurface environments at the U.S. DOE-NABIR Field Research Center at Oak Ridge, Tennessee (ORFRC). Our objectives were to: (1) characterize the dominant iron minerals and related geochemical parameters likely to limit U(VI) speciation, (2) directly quantify reaction rates and pathways of microbial respiration (terminal-electron-accepting) processes which control subsurface sediment chemistry, and (3) identify and enumerate the organisms mediating U(VI) transformation. A total of 31 publications and 47 seminars or meeting presentations were completed under this project. One M.S. thesis (by Nadia North) and a Ph.D. dissertation (by Lainie Petrie-Edwards) were completed at FSU during fall of 2003 and spring of 2005, respectively. Ph.D. students, Denise Akob and Thomas Gihring have continued the student involvement in this research since fall of 2004. All of the above FSU graduate students were heavily involved in the research, as evidenced by their regular attendance at PI meetings and ORFRC workshops

  8. An Overview on Novel Microbial Determination Methods in Pharmaceutical and Food Quality Control

    Directory of Open Access Journals (Sweden)

    Mahboob Nemati

    2016-09-01

    Full Text Available Traditional microbiological methods tend to be labor-intensive and time-consuming. Rapid and novel methods in microbiological tests provide more sensitive, precise and reproducible results compared with conventional methods. In microbiology, the most rapid testing methods belong to the field of biotechnology such as PCR, ELISA, ATP bioluminescence and etc. Nevertheless impedance microbiology, biosensors and analytical procedures to determine microbial constituents are of significance. The present review article was conducted using internet databases and related scientific literatures and articles that provide information on developments in the rapid methods in microbiology. The main focus is on the application of rapid methods in microbial quality control of pharmaceutical products. Reviewed literature showed that rapid methods and automation in microbiology is an advanced area for studying and applying of improved methods in the early detection, and characterization of microorganisms and their products in food, pharmaceutical and cosmetic industrials as well as environmental monitoring and clinical applications. It can be concluded that rapid methods and automation in microbiology should continue as potent and efficient technologies to develop the novel tests to be performed in the future because of the ever-increasing concerns about the safety of food and pharmaceutical products. However the main issues to be considered are the scale up of developed methods and the regulatory requirements.

  9. Limiting Factors for Microbial Fe(III)-Reduction In a Landfill Leachate Polluted Aquifer (Vejen, Denmark)

    DEFF Research Database (Denmark)

    Albrechtsen, Hans-Jørgen; Heron, Gorm; Christensen, Thomas Højlund

    1995-01-01

    Aquifer sediment samples from two locations within the anaerobic leachate plume of a municipal landfill were compared with respect to microbiology (especially Fe(III)-reduction) and geochemistry. The samples close to the landfill were characterized by low contents of Fe(III), whereas samples from...... the more distant cluster were rich in Fe(III)-oxides. The active microbial population seemed to be less dense in samples more distant from the landfill (measured by ATP and phospholipid fatty acids (PLFA)), but the microbial communities were very similar in the two sample clusters according...... to the composition of PLFA. Very little, if any, Fe(III)-reduction was observed close to the landfill, but all the more distant samples showed evident microbially mediated Fe(III)-reduction. After amendment with both acetate and Fe(III), all the samples showed a potential for Fe(III)-reduction, and the in situ Fe...

  10. Importance of microbial pest control agents and their metabolites In relation to the natural microbiota on strawberry

    DEFF Research Database (Denmark)

    Jensen, Birgit; Knudsen, Inge M. B.; Jensen, Dan Funck

    control. A series of laboratory, growth chamber, semi-field and field experiments using strawberry as a model plant focusing on commercial microbial pest control products (MPCPs) or laboratory MPCAs expected to be on the market within 10 years served as our experimental platform. Initially the background...... level of indigenous microbial communities and their mycotoxins/metabolites on strawberries was examined in a field survey with 4 conventional and 4 organic growers with different production practise and geographic distribution. Culturable bacteria, yeasts and filamentous fungi were isolated...... and identified using both chemotaxonomy (fatty acids and metabolite profiling) and morphological characteristics. Microbial communities on strawberries were complex including potential plant pathogens, opportunistic human pathogens, plant disease biocontrol agents and mycotoxin producers. Bacteria were the most...

  11. Factors for Microbial Carbon Sources in Organic and Mineral Soils from Eastern United States Deciduous Forests

    Energy Technology Data Exchange (ETDEWEB)

    Stitt, Caroline R. [Mills College, Oakland, CA (United States)

    2013-09-16

    Forest soils represent a large portion of global terrestrial carbon; however, which soil carbon sources are used by soil microbes and respired as carbon dioxide (CO2) is not well known. This study will focus on characterizing microbial carbon sources from organic and mineral soils from four eastern United States deciduous forests using a unique radiocarbon (14C) tracer. Results from the dark incubation of organic and mineral soils are heavily influenced by site characteristics when incubated at optimal microbial activity temperature. Sites with considerable differences in temperature, texture, and location differ in carbon source attribution, indicating that site characteristics play a role in soil respiration.

  12. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Bill W. Bogan; Brigid M. Lamb; Gemma Husmillo; Kristine Lowe; J. Robert Paterek; John J. Kilbane II

    2004-12-01

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Various chemicals that inhibit the growth and/or the metabolism of corrosion-associated microbes such as sulfate reducing bacteria, denitrifying bacteria, and methanogenic bacteria were evaluated to determine their ability to inhibit corrosion in experiments utilizing pure and mixed bacterial cultures, and planktonic cultures as well as mature biofilms. Planktonic cultures are easier to inhibit than mature biofilms but several compounds were shown to be effective in decreasing the amount of metal corrosion. Of the compounds tested hexane extracts of Capsicum pepper plants and molybdate were the most effective inhibitors of sulfate reducing bacteria, bismuth nitrate was the most effective inhibitor of nitrate reducing bacteria, and 4-((pyridine-2-yl)methylamino)benzoic acid (PMBA) was the most effective inhibitor of methanogenic bacteria. All of these compounds were demonstrated to minimize corrosion due to MIC, at least in some circumstances. The results obtained in this project are consistent with the hypothesis that any compound that disrupts the metabolism of any of the major microbial groups present in corrosion-associated biofilms shows promise in limiting the amount/rate of corrosion. This approach of controlling MIC by controlling the metabolism of biofilms is more environmentally benign than the current approach involving the use of potent biocides, and warrants further investigation.

  13. High arsenic (As concentrations in the shallow groundwaters of southern Louisiana: Evidence of microbial controls on As mobilization from sediments

    Directory of Open Access Journals (Sweden)

    Ningfang Yang

    2016-03-01

    Full Text Available Study region: The Mississippi Delta in southern Louisiana, United States. Study focus: The probable role that microbial respiration plays in As release from the shallow aquifer sediments. New hydrological insights for the region: Shallow groundwaters in southern Louisiana have been reported to contain elevated As concentrations, whereas mechanisms responsible for As release from sediments have rarely been studied in this region. Microbial respiration is generally considered the main mechanism controlling As release in reducing anoxic aquifers such as the shallow aquifers in southern Louisiana and those of the Bengal basin. This study investigates the role microbial respiration plays in As release from shallow aquifer sediments in southern Louisiana through sediment incubation experiments and porewater analysis. Arsenic concentrations were the lowest in the sterilized control experiments, slightly higher in the un-amended experiments, and the highest in the experiments amended with acetate, and especially those amended with both acetate and AQDS (9,10-anthraquinone-2,6-disulfonic acid. Although Fe and Mn generally decreased at the beginning of all the experiments, they did follow a similar trend to As after the decrease. Porewater analysis showed that As and Fe concentrations were generally positively correlated and were higher in the coarse-grained sediments than in the fine-grained sediments. Results of the investigation are consistent with microbial respiration playing a key role in As release from the shallow aquifers sediments in southern Louisiana. Keywords: Groundwater, Arsenic, Microbial respiration

  14. A novel process for synthesis of spherical nanocellulose by controlled hydrolysis of microcrystalline cellulose using anaerobic microbial consortium.

    Science.gov (United States)

    Satyamurthy, P; Vigneshwaran, N

    2013-01-10

    Degradation of cellulose by anaerobic microbial consortium is brought about either by an exocellular process or by secretion of extracellular enzymes. In this work, a novel route for synthesis of nanocellulose is described where in an anaerobic microbial consortium enriched for cellulase producers is used for hydrolysis. Microcrystalline cellulose derived from cotton fibers was subjected to controlled hydrolysis by the anaerobic microbial consortium and the resultant nanocellulose was purified by differential centrifugation technique. The nanocellulose had a bimodal size distribution (43±13 and 119±9 nm) as revealed by atomic force microscopy. A maximum nanocellulose yield of 12.3% was achieved in a span of 7 days. While the conventional process of nanocellulose preparation using 63.5% (w/w) sulfuric acid resulted in the formation of whisker shaped nanocellulose with surface modified by sulfation, controlled hydrolysis by anaerobic microbial consortium yielded spherical nanocellulose also referred to as nano crystalline cellulose (NCC) without any surface modification as evidenced from Fourier transform infrared spectroscopy. Also, it scores over chemo-mechanical production of nanofibrillated cellulose by consuming less energy due to enzyme (cellulase) assisted catalysis. This implies the scope for use of microbial prepared nanocellulose in drug delivery and bio-medical applications requiring bio-compatibility. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Deep subsurface microbial processes

    Science.gov (United States)

    Lovley, D.R.; Chapelle, F.H.

    1995-01-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed redox reactions that influence the geophysical properties of these environments. Furthermore, there is an increasing threat that deep aquifers, an important drinking water resource, may be contaminated by man's activities, and there is a need to predict the extent to which microbial activity may remediate such contamination. Metabolically active microorganisms can be recovered from a diversity of deep subsurface environments. The available evidence suggests that these microorganisms are responsible for catalyzing the oxidation of organic matter coupled to a variety of electron acceptors just as microorganisms do in surface sediments, but at much slower rates. The technical difficulties in aseptically sampling deep subsurface sediments and the fact that microbial processes in laboratory incubations of deep subsurface material often do not mimic in situ processes frequently necessitate that microbial activity in the deep subsurface be inferred through nonmicrobiological analyses of ground water. These approaches include measurements of dissolved H2, which can predict the predominant microbially catalyzed redox reactions in aquifers, as well as geochemical and groundwater flow modeling, which can be used to estimate the rates of microbial processes. Microorganisms recovered from the deep subsurface have the potential to affect the fate of toxic organics and inorganic contaminants in groundwater. Microbial activity also greatly influences 1 the chemistry of many pristine groundwaters and contributes to such phenomena as porosity development in carbonate aquifers, accumulation of undesirably high concentrations of dissolved iron, and production of methane and hydrogen sulfide. Although the last decade has seen a dramatic increase in interest in deep subsurface microbiology, in comparison with the study of

  16. Advanced Experimental Analysis of Controls on Microbial Fe(III) Oxide Reduction - Final Report - 09/16/1996 - 03/16/2001; FINAL

    International Nuclear Information System (INIS)

    Roden, Eric E.

    2001-01-01

    Considering the broad influence that microbial Fe(III) oxide reduction can have on subsurface metal/organic contaminant biogeochemistry, understanding the mechanisms that control this process is critical for predicting the behavior and fate of these contaminants in anaerobic subsurface environments. Knowledge of the factors that influence the rates of growth and activity of Fe(III) oxide-reducing bacteria is critical for predicting (i.e., modeling) the long-term influence of these organisms on the fate of contaminants in the subsurface, and for effectively utilizing Fe(III) oxide reduction and associated geochemical affects for the purpose of subsurface metal/organic contamination bioremediation. This research project will refine existing models for microbiological and geochemical controls on Fe(III) oxide reduction, using laboratory reactor systems that mimic, to varying degrees, the physical and chemical conditions of the subsurface. Novel experimental methods for studying the kinetics of microbial Fe(III) oxide reduction and measuring growth rates of Fe(III) oxide-reducing bacteria will be developed. These new methodologies will be directly applicable to studies on subsurface contaminant transformations directly coupled to or influenced by microbial Fe(III) oxide reduction

  17. In situ Microbial Community Control of the Stability of Bio-Reduced Uranium

    International Nuclear Information System (INIS)

    Long, Phillip E.; McKinley, James P.; White, David C.

    2006-01-01

    In aerobic aquifers typical of many Department of Energy (DOE) legacy waste sites, uranium is present in the oxidized U(VI) form which is soluble and thus mobile compared to U(IV). Previous work at the Old Rifle Uranium Mill Tailings Remedial Action (UMTRA) site demonstrated that biostimulation by acetate injection promoted growth of Geobacteraceae and stimulated the microbial reduction of U(VI) to less soluble U(IV) (1, 4). Despite the potential for oxidative dissolution of bio-reduced U(IV), field experiments at the Old Rifle site show that although the rate of U(VI) reduction decreases following the on-set of sulfate reduction, U(VI) reduction continues even following the cessation of acetate injection (1, 4). However, U(VI) reduction is reversible and the basis for the observed maintenance of U(VI) reduction post-stimulation is a critical but as yet unresolved issue for the application of biostimulation as a treatment technology. The continued U(VI) reduction and the maintenance of reduced U(IV) may result from many factors including U(VI) reduction by sulfate reducing bacteria (SRB), generation of H2S or FeS0.9 which serves as an oxygen sink, or the preferential sorption of U(VI) by microbial cells or biopolymers. The overall goal of the project is to develop an understanding of the mechanisms for the maintenance of bio-reduced uranium in an aerobic aquifer under field conditions following the cessation of electron donor addition

  18. Microbial biomass and bacterial functional diversity in forest soils: effects of organic matter removal, compaction, and vegetation control

    Science.gov (United States)

    Qingchao Li; H. Lee Allen; Arthur G. Wollum

    2004-01-01

    The effects of organic matter removal, soil compaction, and vegetation control on soil microbial biomass carbon, nitrogen, C-to-N ratio, and functional diversity were examined in a 6-year loblolly pine plantation on a Coastal Plain site in eastern North Carolina, USA. This experimental plantation was established as part of the US Forest Service's Long Term Soil...

  19. The use of controlled microbial cenoses in producers' link to increase steady functioning of artificial ecosystems

    Science.gov (United States)

    Somova, Lydia; Mikheeva, Galina; Somova, Lydia

    The life support systems (LSS) for long-term missions are to use cycling-recycling systems, including biological recycling. Simple ecosystems include 3 links: producers (plants), consumers (man, animals) and reducers (microorganisms). Microorganisms are substantial component of every link of LSS. Higher plants are the traditional regenerator of air and producer of food. They should be used in many successive generations of their reproduction in LSS. Controlled microbiocenoses can increase productivity of producer's link and protect plants from infections. The goal of this work was development of methodological bases of formation of stable, controlled microbiocenoses, intended for increase of productivity of plants and for obtaining ecologically pure production of plants. Main results of our investigations: 1. Experimental microbiocenoses, has been produced in view of the developed methodology on the basis of natural association of microorganisms by long cultivation on specially developed medium. Dominating groups are bacteria of genera: Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Rhodopseudomonas and yeast of genera: Kluyveromyces, Saccharomyces, Torulopsis. 2. Optimal parameters of microbiocenosis cultivation (t, pH, light exposure, biogenic elements concentrations) were experimentally established. Conditions of cultivation on which domination of different groups of microbiocenosis have been found. 3. It was shown, that processing of seeds of wheat, oats, bulbs and plants Allium cepa L. (an onions) with microbial association raised energy of germination of seeds and bulbs and promoted the increase (on 20-30 %) of growth green biomass and root system of plants in comparison with the control. This work is supported by grant, Yenissey , 07-04-96806

  20. Microbial antagonism as a potential solution for controlling selected root pathogens of crops

    Science.gov (United States)

    Cooper, Sarah; Agnew, Linda; Pereg, Lily

    2016-04-01

    Root pathogens of crops can cause large reduction in yield, however, there is a limited range of effective methods to control such pathogens. Soilborne pathogens that infect roots often need to survive in the rhizosphere, where there is high competition from other organisms. In such hot spots of microbial activity and growth, supported by root exudates, microbes have evolved antagonistic mechanisms that give them competitive advantages in winning the limited resources. Among these mechanisms is antibiosis, with production of some significant antifungal compounds including, antibiotics, volatile organic compounds, hydrogen cyanide and lytic enzymes. Some of these mechanisms may suppress disease through controlling the growth of root pathogens. In this project we isolated various fungi and bacteria that suppress the growth of cotton pathogens in vitro. The pathogen-suppressive microbes were isolated from cotton production soils that are under different management strategies, with and without the use of organic amendments. The potential of pathogen-suppressing microbes for controlling the black root rot disease, caused by the soilborne pathogen Thielaviopsis basicola, was confirmed using soil assays. We identified isolates with potential use as inoculant for cotton production in Australia. Having isolated a diverse group of antagonistic microbes enhances the probability that some would survive well in the soil and provide an alternative approach to address the problem of root disease affecting agricultural crops.

  1. Control of Microbial Sulfide Production with Biocides and Nitrate in Oil Reservoir Simulating Bioreactors.

    Directory of Open Access Journals (Sweden)

    Yuan eXue

    2015-12-01

    Full Text Available Oil reservoir souring by the microbial reduction of sulfate to sulfide is unwanted, because it enhances corrosion of metal infrastructure used for oil production and processing. Reservoir souring can be prevented or remediated by the injection of nitrate or biocides, although injection of biocides into reservoirs is not commonly done. Whether combined application of these agents may give synergistic reservoir souring control is unknown. In order to address this we have used up-flow sand-packed bioreactors injected with 2 mM sulfate and volatile fatty acids (VFA, 3 mM each of acetate, propionate and butyrate at a flow rate of 3 or 6 pore volumes per day. Pulsed injection of the biocides glutaraldehyde (Glut, benzalkonium chloride (BAC and cocodiamine was used to control souring. Souring control was determined as the recovery time (RT needed to re-establish an aqueous sulfide concentration of 0.8-1 mM (of the 1.7-2 mM before the pulse. Pulses were either for a long time (120 h at low concentration (long-low or for a short time (1 h at high concentration (short-high. The short-high strategy gave better souring control with Glut, whereas the long-low strategy was better with cocodiamine. Continuous injection of 2 mM nitrate alone was not effective, because 3 mM VFA can fully reduce both 2 mM nitrate to nitrite and N2 and, subsequently, 2 mM sulfate to sulfide. No synergy was observed for short-high pulsed biocides and continuously injected nitrate. However, use of continuous nitrate and long-low pulsed biocide gave synergistic souring control with BAC and Glut, as indicated by increased RTs in the presence, as compared to the absence of nitrate. Increased production of nitrite, which increases the effectiveness of souring control by biocides, is the most likely cause for this synergy.

  2. Disturbance Alters the Relative Importance of Topographic and Biogeochemical Controls on Microbial Activity in Temperate Montane Forests

    Directory of Open Access Journals (Sweden)

    Rebecca A. Lybrand

    2018-02-01

    Full Text Available Fire and pathogen-induced tree mortality are the two dominant forms of disturbance in Western U.S. montane forests. We investigated the consequences of both disturbance types on the controls of microbial activity in soils from 56 plots across a topographic gradient one year after the 2012 High Park wildfire in Colorado. Topsoil biogeochemistry, soil CO2 efflux, potential exoenzyme activities, and microbial biomass were quantified in plots that experienced fire disturbance, beetle disturbance, or both fire and beetle disturbance, and in plots where there was no recent evidence of disturbance. Soil CO2 efflux, N-, and P-degrading exoenzyme activities in undisturbed plots were positively correlated with soil moisture, estimated from a topographic wetness index; coefficient of determinations ranged from 0.5 to 0.65. Conversely, the same estimates of microbial activities from fire-disturbed and beetle-disturbed soils showed little correspondence to topographically inferred wetness, but demonstrated mostly negative relationships with soil pH (fire only and mostly positive relationships with DOC/TDN (dissolved organic carbon/total dissolved nitrogen ratios for both disturbance types. The coefficient of determination for regressions of microbial activity with soil pH and DOC/TDN reached 0.8 and 0.63 in fire- and beetle-disturbed forests, respectively. Drivers of soil microbial activity change as a function of disturbance type, suggesting simple mathematical models are insufficient in capturing the impact of disturbance in forests.

  3. Childhood microbial keratitis

    Directory of Open Access Journals (Sweden)

    Abdullah G Al Otaibi

    2012-01-01

    Conclusion: Children with suspected microbial keratitis require comprehensive evaluation and management. Early recognition, identifying the predisposing factors and etiological microbial organisms, and instituting appropriate treatment measures have a crucial role in outcome. Ocular trauma was the leading cause of childhood microbial keratitis in our study.

  4. Protease inhibitors as a possible new factor in agricultural plant protection against microbial and fungal attack

    Czech Academy of Sciences Publication Activity Database

    Navrátil, Oldřich; Kodrík, Dalibor; Kludkiewicz, Barbara; Vinokurov, Konstantin; Sehnal, František; Horáčková, V.

    2012-01-01

    Roč. 73, Jan 2012 (2012), s. 61-67 ISSN 1027-3115 R&D Projects: GA MŠk 1M06030; GA MZe QI91A229 Institutional research plan: CEZ:AV0Z50380511; CEZ:AV0Z50070508 Keywords : potato * transgenosis * microbial and fungal pathogens Subject RIV: EB - Genetics ; Molecular Biology http://home.ueb.cas.cz/publikace/2012_Navratil_IOBC_61-67.pdf

  5. Microbial community responses in forest mineral soil to compaction, organic matter removal, and vegetation control

    Science.gov (United States)

    Matt D. Busse; Samual E. Beattie; Robert F. Powers; Filpe G. Sanchez; Allan E. Tiarks

    2006-01-01

    We tested three disturbance hypotheses in young conifer plantations: H1: soil compaction and removal of surface organic matter produces sustained changes in microbial community size, activity, and structure in mineral soil; H2: microbial community characteristics in mineral soil are linked to the recovery of plant diversity...

  6. The Role of Microbial Community Composition in Controlling Soil Respiration Responses to Temperature.

    Science.gov (United States)

    Auffret, Marc D; Karhu, Kristiina; Khachane, Amit; Dungait, Jennifer A J; Fraser, Fiona; Hopkins, David W; Wookey, Philip A; Singh, Brajesh K; Freitag, Thomas E; Hartley, Iain P; Prosser, James I

    2016-01-01

    Rising global temperatures may increase the rates of soil organic matter decomposition by heterotrophic microorganisms, potentially accelerating climate change further by releasing additional carbon dioxide (CO2) to the atmosphere. However, the possibility that microbial community responses to prolonged warming may modify the temperature sensitivity of soil respiration creates large uncertainty in the strength of this positive feedback. Both compensatory responses (decreasing temperature sensitivity of soil respiration in the long-term) and enhancing responses (increasing temperature sensitivity) have been reported, but the mechanisms underlying these responses are poorly understood. In this study, microbial biomass, community structure and the activities of dehydrogenase and β-glucosidase enzymes were determined for 18 soils that had previously demonstrated either no response or varying magnitude of enhancing or compensatory responses of temperature sensitivity of heterotrophic microbial respiration to prolonged cooling. The soil cooling approach, in contrast to warming experiments, discriminates between microbial community responses and the consequences of substrate depletion, by minimising changes in substrate availability. The initial microbial community composition, determined by molecular analysis of soils showing contrasting respiration responses to cooling, provided evidence that the magnitude of enhancing responses was partly related to microbial community composition. There was also evidence that higher relative abundance of saprophytic Basidiomycota may explain the compensatory response observed in one soil, but neither microbial biomass nor enzymatic capacity were significantly affected by cooling. Our findings emphasise the key importance of soil microbial community responses for feedbacks to global change, but also highlight important areas where our understanding remains limited.

  7. Glyphosate toxicity and the effects of long-term vegetation control on soil microbial communities

    Science.gov (United States)

    Matt D. Busse; Alice W. Ratcliff; Carol J. Stestak; Robert F. Powers

    2001-01-01

    We assessed the direct and indirect effect of the herbicide glyphosate on soil microbial communities from soil bioassays at glyphosate concentrations up to 100-fold greater than expected following a single field application. Indirect effects on microbial biomass, respiration, and metabolic diversity (Biolog and catabolic response profile) were compared seasonally after...

  8. Evaluation of some microbial agents, natural and chemical compounds for controlling tomato leaf miner, Tuta absoluta (Meyrick (Lepidoptera: Gelechiidae

    Directory of Open Access Journals (Sweden)

    Abd El-Ghany Nesreen M.

    2016-12-01

    Full Text Available Solanaceous plants have a great economic impact in Egypt. These groups of plants include potatoes, tomatoes and eggplants. The new invasive pest of tomatoes, Tuta absoluta (Meyrick causes the greatest crop losses which can range from 60 to 100%. After its detection in Egypt during the last half of 2009, it spread quickly to all provinces in the country. We aiming to propose a sustainable control program for this devastating pest. In this research we tested three groups of control agents. The first was microbial and natural, the second - plant extracts and the third - chemical insecticides. Our results showed that the impact of T. absoluta can be greatly reduced by the use of sustainable control measures represented by different insecticide groups. Bioassay experiments showed that this devastating pest can be controlled with some compounds that give high mortality rates. Of these compounds, spinosad and Beauveria bassiana, microbial control agents, followed by azadirachtin, gave the best results in controlling T. absoluta. Of the chemical insecticides, lambda-cyhalotrin was the most effective, followed by lufenuron and profenofos. In conclusion we encourage farmers to use microbial and natural control measures in combating the tomato leafminer, T. absoluta, in Integrated Pest Mangement (IPM programs.

  9. Phytoalexins as Possible Controlling Agents of Microbial Spoilage of Irradiated Fresh Fruit and Vegetables During Storage

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed, S. A. [Radiobiology Department, Nuclear Research Center, Atomic Energy Commission, Cairo (Egypt)

    1978-04-15

    The decline in bio generating capacity to form natural antibiotic compounds (phytoalexins), rishitin and lubimin in potato tubers and rishitin in tomatoes, after gamma irradiation seems to be the essence of the suppression of natural immunity exhibited by an increase in per cent of rotted tubers and fruits during storage. In vitro studies postulated that the rot-causing fungi Phytophthora infestons (Mond) De Bary, Alternaria solani (Ellis and Martin) James and Grout, Botrytis cinerea Persson., Fusarium oxysporum Syder and Hansen and Rhizopus stolonifer Ehrenberg were significantly controlled by the application of phytoalexins that had been initially formed by potato tubers (rishitin), tomato fruits (rishitin) and pepper fruits (capsidiol). In vivo studies revealed that post-irradiation treatment of potato tubers and tomato fruits with phytoalexins that had been produced by the same plant organ or by another of the same family seems to be experimentally feasible to reduce the radiation dose or increase the efficiency of irradiation in controlling microbial spoilage during storage of irradiated potatoes and tomatoes. (author)

  10. Phytoalexins as possible controlling agents of microbial spoilage of irradiated fresh fruit and vegetables during storage

    International Nuclear Information System (INIS)

    El-Sayed, S.A.

    1978-01-01

    The decline in biogenerating capacity to form natural antibiotic compounds (phytoalexins), rishitin and lubimin in potato tubers and rishitin in tomatoes, after gamma irradiation seems to be the essence of the suppression of natural immunity exhibited by an increase in per cent of rotted tubers and fruits during storage. In vitro studies postulated that the rot-causing fungi Phytophthora infestans (Mond) De Bary, Alternaria solani (Ellis and Martin) James and Grout, Botrytis cinerea Persson., Fusarium oxysporum Syder and Hansen and Rhizopus stolonifer Ehrenberg were significantly controlled by the application of phytoalexins that had been initially formed by potato tubers (rishitin), tomato fruits (rishitin) and pepper fruits (capsidiol). In vivo studies revealed that post-irradiation treatment of potato tubers and tomato fruits with phytoalexins that had been produced by the same plant organ or by another of the same family seems to be experimentally feasible to reduce the radiation dose or increase the efficiency of irradiation in controlling microbial spoilage during storage of irradiated potatoes and tomatoes. (author)

  11. By passing microbial resistance: xylitol controls microorganisms growth by means of its anti-adherence property.

    Science.gov (United States)

    Ferreira, Aline S; Silva-Paes-Leme, Annelisa F; Raposo, Nádia R B; da Silva, Sílvio S

    2015-01-01

    Xylitol is an important polyalcohol suitable for use in odontological, medical and pharmaceutical products and as an additive in food. The first studies on the efficacy of xylitol in the control and treatment of infections started in the late 1970s and it is still applied for this purpose, with safety and very little contribution to resistance. Xylitol seems to act against microorganisms exerting an anti-adherence effect. Some research studies have demonstrated its action against Gram-positive and Gram-negative bacteria and yeasts. However, a clear explanation of how xylitol is effective has not been completely established yet. Some evidence shows that xylitol acts on gene expression, down-regulating the ones which are involved in the microorganisms' virulence, such as capsule formation. Another possible clarification is that xylitol blocks lectin-like receptors. The most important aspect is that, over time, xylitol bypasses microbial resistance and succeeds in controlling infection, either alone or combined with another compound. In this review, the effect of xylitol in inhibiting the growth of a different microorganism is described, focusing on studies in which such an anti-adherent property was highlighted. This is the first mini-review to describe xylitol as an anti-adherent compound and take into consideration how it exerts such action.

  12. Comparing a microbial biocide and chlorine as zebra mussel control strategies in an Irish drinking water treatment plant

    OpenAIRE

    Sara Meehan; Frances E. Lucy; Bridget Gruber; Sarahann Rackl

    2013-01-01

    A need exists for an environmentally friendly mussel control method to replace chlorine and other traditional control methods currentlyutilised in drinking water plants and other infested facilities. Zequanox® is a newly commercialised microbial biocide for zebra and quaggamussels comprised of killed Pseudomonas fluorescens CL145A cells. The objective of this study was to compare the efficacy of adevelopmental formulation of Zequanox (referred to as MBI 401 FDP) and chlorine treatments on adu...

  13. Key Factors Controlling the Applicability and Efficiency of Bioremediation of Chlorinated Ethenes In Situ

    Science.gov (United States)

    Zhang, M.; Yoshikawa, M.; Takeuchi, M.; Komai, T.

    2012-12-01

    Bioremediation has been considered as one of environmentally friendly and cost effective approaches for cleaning up the sites polluted by organic contaminants, such as chlorinated ethenes. Although bioremediation, in its widest sense, is not new, and many researches have been performed on bioremediation of different kinds of pollutants, an effective design and implication of in situ bioremediation still remains a challenging problem because of the complexity. Many factors may affect the applicability and efficiency of bioremediation of chlorinated ethenes in situ, which include the type and concentration of contaminants, biological, geological and hydro-geological conditions of the site, physical and chemical characteristics of groundwater and soils to be treated, as well as the constraints in engineering. In this presentation, an overview together with a detailed discussion on each factor will be provided. The influences of individual factors are discussed using the data obtained or cited from different sites and experiments, and thus under different environmental conditions. The results of this study illustrated that 1) the establishment of microbial consortium is of crucial importance for a complete degradation of chlorinated ethenes, 2) in situ control of favorable conditions for increasing microbial activities for bio-degradation through a designed pathway is the key to success, 3) the focus of a successful remediation system is to design an effective delivery process that is capable of producing adequate amendment mixing of contaminant-degrading bacteria, appropriate concentrations of electron acceptors, electron donors, and microbial nutrients in the subsurface treatment area.

  14. Safety factor profile control in a tokamak

    CERN Document Server

    Bribiesca Argomedo, Federico; Prieur, Christophe

    2014-01-01

    Control of the Safety Factor Profile in a Tokamak uses Lyapunov techniques to address a challenging problem for which even the simplest physically relevant models are represented by nonlinear, time-dependent, partial differential equations (PDEs). This is because of the  spatiotemporal dynamics of transport phenomena (magnetic flux, heat, densities, etc.) in the anisotropic plasma medium. Robustness considerations are ubiquitous in the analysis and control design since direct measurements on the magnetic flux are impossible (its estimation relies on virtual sensors) and large uncertainties remain in the coupling between the plasma particles and the radio-frequency waves (distributed inputs). The Brief begins with a presentation of the reference dynamical model and continues by developing a Lyapunov function for the discretized system (in a polytopic linear-parameter-varying formulation). The limitations of this finite-dimensional approach motivate new developments in the infinite-dimensional framework. The t...

  15. The importance of anabolism in microbial control over soil carbon storage

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Chao; Schimel, Joshua P.; Jastrow, Julie D.

    2017-07-25

    Studies of the decomposition, transformation and stabilization of soil organic matter (SOM) have dramatically increased in recent years owing to growing interest in studying the global carbon (C) cycle as it pertains to climate change. While it is readily accepted that the magnitude of the organic C reservoir in soils depends upon microbial involvement, as soil C dynamics are ultimately the consequence of microbial growth and activity, it remains largely unknown how these microorganism-mediated processes lead to soil C stabilization. Here, we define two pathways—ex vivo modification and in vivo turnover—which jointly explain soil C dynamics driven by microbial catabolism and/or anabolism. Accordingly, we use the conceptual framework of the soil ‘microbial carbon pump’ (MCP) to demonstrate how microorganisms are an active player in soil C storage. The MCP couples microbial production of a set of organic compounds to their further stabilization, which we define as the entombing effect. This integration captures the cumulative long-term legacy of microbial assimilation on SOM formation, with mechanisms (whether via physical protection or a lack of activation energy due to chemical composition) that ultimately enable the entombment of microbial-derived C in soils. We propose a need for increased efforts and seek to inspire new studies that utilize the soil MCP as a conceptual guideline for improving mechanistic understandings of the contributions of soil C dynamics to the responses of the terrestrial C cycle under global change.

  16. Controlling the occurrence of power overshoot by adapting microbial fuel cells to high anode potentials

    KAUST Repository

    Zhu, Xiuping

    2013-04-01

    Power density curves for microbial fuel cells (MFCs) often show power overshoot, resulting in inaccurate estimation of MFC performance at high current densities. The reasons for power overshoot are not well understood, but biofilm acclimation and development are known factors. In order to better explore the reasons for power overshoot, exoelectrogenic biofilms were developed at four different anode potentials (-0.46 V, -0.24 V, 0 V, and 0.50 V vs. Ag/AgCl), and then the properties of the biofilms were examined using polarization tests and cyclic voltammetry (CV). The maximum power density of the MFCs was 1200±100 mW/m2. Power overshoot was observed in MFCs incubated at -0.46 V, but not those acclimated atmore positive potentials, indicating that bacterial activitywas significantly influenced by the anode acclimation potential. CV results further indicated that power overshoot of MFCs incubated at the lowest anode potential was associatedwith a decreasing electroactivity of the anodic biofilm in the high potential region,which resulted from a lack of sufficient electron transfer components to shuttle electrons at rates needed for these more positive potentials. © 2012 Elsevier B.V.

  17. Utilization and control of ecological interactions in polymicrobial infections and community-based microbial cell factories [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Vinoth Wigneswaran

    2016-03-01

    Full Text Available Microbial activities are most often shaped by interactions between co-existing microbes within mixed-species communities. Dissection of the molecular mechanisms of species interactions within communities is a central issue in microbial ecology, and our ability to engineer and control microbial communities depends, to a large extent, on our knowledge of these interactions. This review highlights the recent advances regarding molecular characterization of microbe-microbe interactions that modulate community structure, activity, and stability, and aims to illustrate how these findings have helped us reach an engineering-level understanding of microbial communities in relation to both human health and industrial biotechnology.

  18. Effect of probiotics (Saccharomyces boulardii) on microbial translocation and inflammation in HIV-treated patients: a double-blind, randomized, placebo-controlled trial.

    Science.gov (United States)

    Villar-García, Judit; Hernández, Juan J; Güerri-Fernández, Robert; González, Alicia; Lerma, Elisabet; Guelar, Ana; Saenz, David; Sorlí, Lluisa; Montero, Milagro; Horcajada, Juan P; Knobel Freud, Hernando

    2015-03-01

    Microbial translocation has been associated with an increase in immune activation and inflammation in HIV infection despite effective highly active antiretroviral therapy. It has been shown that some probiotics have a beneficial effect by reducing intestinal permeability and, consequently, microbial translocation. To assess changes in microbial translocation and inflammation after treatment with probiotics (Saccharomyces boulardii) in HIV-1-infected patients with virologic suppression. A double-blind, randomized, placebo-controlled trial was conducted in 44 nonconsecutive HIV-1-infected patients with viral load of boulardii decreases microbial translocation (LBP) and inflammation parameters (IL-6) in HIV-1-infected patients with long-term virologic suppression.

  19. Comparison of fluid geochemistry and microbiology of multiple organic-rich reservoirs in the Illinois Basin, USA: Evidence for controls on methanogenesis and microbial transport

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, M.E.; McIntosh, J.C.; Bates, B.L.; Kirk, M.F.; Martini, A.M. [University of Arizona, Tucson, AZ (United States)

    2011-04-01

    The Illinois Basin, USA, is an ideal location to investigate hydrogeochemical factors controlling methanogenesis as microbial methane accumulations occur: (1) in three organic-rich reservoirs of different geologic ages and organic matter types - Upper Devonian New Albany Shale (up to 900 m depth), Pennsylvanian coals (up to 600 m depth), and Quaternary glacial sediments (shallow aquifers); (2) across steep salinity gradients; and (3) with variable concentrations of SO{sub 4}{sup 2-}. For all three organic-rich reservoirs aqueous geochemical conditions are favorable for microbial methanogenesis, with near neutral pH, SO{sub 4}{sup 2-} concentrations {gt}2 mM, and Cl{sup -} concentrations {lt}3 M. Also, carbon isotopic fractionation of CH{sub 4}, CO{sub 2}, and DIC is consistent with microbial methanogenesis, and increased carbon isotopic fractionation with average reservoir depth corresponds to a decrease of groundwater flushing rates with average depth of reservoir. Plots of stable isotopes of water and Cl{sup -} show mixing between a brine endmember and freshwater, suggesting that meteoric groundwater recharge has affected all microbial methanogenic systems. Additionally, similar methanogenic communities are present in all three reservoirs with comparable cell counts (8.69E3-2.58E6 cells/mL). TRFLP results show low numbers of archaea species with only two dominant groups of base pairs in coals, shale, and limestone aquifers. These results compare favorably with other methanogen-containing deep subsurface environments. The matching of variations between methanogenic TRFLP data and conservative tracers suggests that deep circulation of meteoric waters influenced archaeal communities in the Illinois Basin.

  20. Microbial control of phytophagous invertebrate pests in South Africa: Current status and future prospects.

    Science.gov (United States)

    Hatting, Justin L; Moore, Sean D; Malan, Antoinette P

    2018-02-07

    Invertebrate pests pose a significant threat to food security on the African continent. In response, South Africa has become one of the largest importers of chemical pesticides in sub-Saharan Africa, with several hundred active ingredients registered. To address the over-reliance on such chemicals, the South African Department of Agriculture, Forestry and Fisheries (DAFF) has eliminated or restricted several pesticides since the late 1970s. The recent launch of the South African National Bio-Economy Strategy and establishment of the South African Bioproducts Organisation (SABO), together with new guidelines for registration of biopesticides in 2015, also support this endeavour. Concurrently, entomopathogen-related research and bioproduct development has increased over the past decade. Currently, 31 products (seven manufactured locally) are registered under the Fertilizers, Farm Feeds, Agricultural Remedies and Stock Remedies Act 36 of 1947. Commercially important microbes include Beauveria bassiana (Cordycipitaceae), Metarhizium anisopliae (Clavicipitaceae), Cydia pomonella granulovirus, Cryptophlebia leucotreta granulovirus, Helicoverpa armigera nucleopolyhedrovirus (Baculoviridae) and Bacillus thuringiensis subsp. kurstaki and B. thuringiensis subsp. aizawai (Bacillaceae). Both parasitic and entomopathogenic nematodes (EPNs) show potential for development as bioinsecticides with one commercial EPN product, based on Heterorhabditis bacteriophora (Heterorhabditidae), registered under the Act. Rapid scientific progression, supported by a favourable legislative environment, should facilitate further advances in microbial control of phytophagous invertebrate pests in South Africa. Copyright © 2018 Elsevier Inc. All rights reserved.

  1. Microbial Performance of Food Safety Control and Assurance Activities in a Fresh Produce Processing Sector Measured Using a Microbial Assessment Scheme and Statistical Modeling

    DEFF Research Database (Denmark)

    Njage, Patrick Murigu Kamau; Sawe, Chemutai Tonui; Onyango, Cecilia Moraa

    2017-01-01

    assessment scheme and statistical modeling were used to systematically assess the microbial performance of core control and assurance activities in five Kenyan fresh produce processing and export companies. Generalized linear mixed models and correlated random-effects joint models for multivariate clustered...... the maximum safety level for environmental samples. Escherichia coli was detected in five of the six CSLs, including the final product. Among the processing-environment samples, the hand or glove swabs of personnel revealed a higher level of predicted contamination with E. coli, and 80% of the factories were...... of contamination with coliforms in water at the inlet than in the final rinse water. Four (80%) of the five assessed processors had poor to unacceptable counts of Enterobacteriaceae on processing surfaces. Personnel-, equipment-, and product-related hygiene measures to improve the performance of preventive...

  2. Controlling the occurrence of power overshoot by adapting microbial fuel cells to high anode potentials

    KAUST Repository

    Zhu, Xiuping; Tokash, Justin C.; Hong, Yiying; Logan, Bruce E.

    2013-01-01

    Power density curves for microbial fuel cells (MFCs) often show power overshoot, resulting in inaccurate estimation of MFC performance at high current densities. The reasons for power overshoot are not well understood, but biofilm acclimation

  3. Biodegradation: Updating the Concepts of Control for Microbial Cleanup in Contaminated Aquifers

    DEFF Research Database (Denmark)

    Meckenstock, Rainer U.; Elsner, Martin; Griebler, Christian

    2015-01-01

    Biodegradation is one of the most favored and sustainable means of removing organic pollutants from contaminated aquifers but the major steering factors are still surprisingly poorly understood. Growing evidence questions some of the established concepts for control of biodegradation. Here, we...... on the controls of biodegradation in contaminant plumes. These include the plume fringe concept, transport limitations, and transient conditions as currently underestimated processes affecting biodegradation....

  4. Mineralogic control on abundance and diversity of surface-adherent microbial communities

    Science.gov (United States)

    Mauck, Brena S.; Roberts, Jennifer A.

    2007-01-01

    In this study, we investigated the role of mineral-bound P and Fe in defining microbial abundance and diversity in a carbon-rich groundwater. Field colonization experiments of initially sterile mineral surfaces were combined with community structure characterization of the attached microbial population. Silicate minerals containing varying concentrations of P (∼1000 ppm P) and Fe (∼4 wt % Fe 2 O3), goethite (FeOOH), and apatite [Ca5(PO4)3(OH)] were incubated for 14 months in three biogeochemically distinct zones within a petroleum-contaminated aquifer. Phospholipid fatty acid analysis of incubated mineral surfaces and groundwater was used as a measure of microbial community structure and biomass. Microbial biomass on minerals exhibited distinct trends as a function of mineralogy depending on the environment of incubation. In the carbon-rich, aerobic groundwater attached biomass did not correlate to the P- or Fe- content of the mineral. In the methanogenic groundwater, however, biomass was most abundant on P-containing minerals. Similarly, in the Fe-reducing groundwater a correlation between Fe-content and biomass was observed. The community structure of the mineral-adherent microbial population was compared to the native groundwater community. These two populations were significantly different regardless of mineralogy, suggesting differentiation of the planktonic community through attachment, growth, and death of colonizing cells. Biomarkers specific for dissimilatory Fe-reducing bacteria native to the aquifer were identified only on Fe-containing minerals in the Fe-reducing groundwater. These results demonstrate that the trace nutrient content of minerals affects both the abundance and diversity of surface-adherent microbial communities. This behavior may be a means to access limiting nutrients from the mineral, creating a niche for a particular microbial population. These results suggest that heterogeneity of microbial populations and their associated

  5. Microbial Pest Control Agents: Are they a Specific And Safe Tool for Insect Pest Management?

    Science.gov (United States)

    Deshayes, Caroline; Siegwart, Myriam; Pauron, David; Froger, Josy-Anne; Lapied, Bruno; Apaire-Marchais, Véronique

    2017-01-01

    Microorganisms (viruses, bacteria and fungi) or their bioactive agents can be used as active substances and therefore are referred as Microbial Pest Control Agents (MPCA). They are used as alternative strategies to chemical insecticides to counteract the development of resistances and to reduce adverse effects on both environment and human health. These natural entomopathogenic agents, which have specific modes of action, are generally considered safer as compared to conventional chemical insecticides. Baculoviruses are the only viruses being used as the safest biological control agents. They infect insects and have narrow host ranges. Bacillus thuringiensis (Bt) is the most widely and successfully used bioinsecticide in the integrated pest management programs in the world. Bt mainly produces crystal delta-endotoxins and secreted toxins. However, the Bt toxins are not stable for a very long time and are highly sensitive to solar UV. So genetically modified plants that express toxins have been developed and represent a large part of the phytosanitary biological products. Finally, entomopathogenic fungi and particularly, Beauveria bassiana and Metarhizium anisopliae, are also used for their insecticidal properties. Most studies on various aspects of the safety of MPCA to human, non-target organisms and environment have only reported acute but not chronic toxicity. This paper reviews the modes of action of MPCA, their toxicological risks to human health and ecotoxicological profiles together with their environmental persistence. This review is part of the special issue "Insecticide Mode of Action: From Insect to Mammalian Toxicity". Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  6. Analyses of the influencing factors of soil microbial functional gene diversity in tropical rainforest based on GeoChip 5.0

    Directory of Open Access Journals (Sweden)

    Jing Cong

    2015-09-01

    Full Text Available To examine soil microbial functional gene diversity and causative factors in tropical rainforests, we used a microarray-based metagenomic tool named GeoChip 5.0 to profile it. We found that high microbial functional gene diversity and different soil microbial metabolic potential for biogeochemical processes were considered to exist in tropical rainforest. Soil available nitrogen was the most associated with soil microbial functional gene structure. Here, we mainly describe the experiment design, the data processing, and soil biogeochemical analyses attached to the study in details, which could be published on BMC microbiology Journal in 2015, whose raw data have been deposited in NCBI's Gene Expression Omnibus (accession number GSE69171.

  7. Microbial Characteristics of Peri-Implantitis : A Case-Control Study

    NARCIS (Netherlands)

    de Waal, Y C M; Eijsbouts, H V L C; Winkel, E G; van Winkelhoff, A J

    BACKGROUND: Aim of this case-control study was to compare oral microbiological characteristics of subjects with healthy peri-implant conditions and subjects with peri-implantitis and to explore the influence of various patient-related and implant-related factors on the microbiological

  8. Insights into environmental controls on microbial communities in a continental serpentinite aquifer using a microcosm-based approach.

    Science.gov (United States)

    Crespo-Medina, Melitza; Twing, Katrina I; Kubo, Michael D Y; Hoehler, Tori M; Cardace, Dawn; McCollom, Tom; Schrenk, Matthew O

    2014-01-01

    Geochemical reactions associated with serpentinization alter the composition of dissolved organic compounds in circulating fluids and potentially liberate mantle-derived carbon and reducing power to support subsurface microbial communities. Previous studies have identified Betaproteobacteria from the order Burkholderiales and bacteria from the order Clostridiales as key components of the serpentinite-hosted microbiome, however there is limited knowledge of their metabolic capabilities or growth characteristics. In an effort to better characterize microbial communities, their metabolism, and factors limiting their activities, microcosm experiments were designed with fluids collected from several monitoring wells at the Coast Range Ophiolite Microbial Observatory (CROMO) in northern California during expeditions in March and August 2013. The incubations were initiated with a hydrogen atmosphere and a variety of carbon sources (carbon dioxide, methane, acetate, and formate), with and without the addition of nutrients and electron acceptors. Growth was monitored by direct microscopic counts; DNA yield and community composition was assessed at the end of the 3 month incubation. For the most part, results indicate that bacterial growth was favored by the addition of acetate and methane, and that the addition of nutrients and electron acceptors had no significant effect on microbial growth, suggesting no nutrient- or oxidant-limitation. However, the addition of sulfur amendments led to different community compositions. The dominant organisms at the end of the incubations were closely related to Dethiobacter sp. and to the family Comamonadaceae, which are also prominent in culture-independent gene sequencing surveys. These experiments provide one of first insights into the biogeochemical dynamics of the serpentinite subsurface environment and will facilitate experiments to trace microbial activities in serpentinizing ecosystems.

  9. Factors controlling contrail cirrus optical depth

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2009-08-01

    Full Text Available Aircraft contrails develop into contrail cirrus by depositional growth and sedimentation of ice particles and horizontal spreading due to wind shear. Factors controlling this development include temperature, ice supersaturation, thickness of ice-supersaturated layers, and vertical gradients in the horizontal wind field. An analytical microphysical cloud model is presented and validated that captures these processes. Many individual contrail cirrus are simulated that develop differently owing to the variability in the controlling factors, resulting in large samples of cloud properties that are statistically analyzed. Contrail cirrus development is studied over the first four hours past formation, similar to the ages of line-shaped contrails that were tracked in satellite imagery on regional scales. On these time scales, contrail cirrus optical depth and microphysical variables exhibit a marked variability, expressed in terms of broad and skewed probability distribution functions. Simulated mean optical depths at a wavelength of 0.55 μm range from 0.05-0.5 and a substantial fraction 20-50% of contrail cirrus stay subvisible (optical depth <0.02, depending on meteorological conditions.

    A detailed analysis based on an observational case study over the continental USA suggests that previous satellite measurements of line-shaped persistent contrails have missed about 89%, 50%, and 11% of contrails with optical depths 0-0.05, 0.05-0.1, and 0.1-0.2, respectively, amounting to 65% of contrail coverage of all optical depths. When comparing observations with simulations and when estimating the contrail cirrus climate impact, not only mean values but also the variability in optical depth and microphysical properties need to be considered.

  10. Microbial Immobilization of Si, Mn, Fe, and Sr Ions in the Nacreous Layer of Sinohyliopsis schlegeli and Environmental Factors

    Science.gov (United States)

    Tazaki, Kazue; Morii, Issei

    Environmental changes recorded in the shell nacre of Sinohyliopsis schlegeli were observed with elemental factors of characteristic water and nutrition for eight months in a cultivated drainage pond at Kanazawa University, Ishikawa Prefecture, Japan. Tetracycline as an indicator was injected into the shell nacre once every month from May to November in 2007. Water qualities such as the pH, redox potential, electrical conductivity, dissolved oxygen concentration, and water temperature were measured periodically, and the suspended solids in the water were removed by filtration for optical microscopy, X-ray fluorescence analysis, and scanning electron microscopy-energy dispersive X-ray (SEM-EDX) observations. X-ray fluorescence chemical analysis of shell nacre indicated layers with strong tetracycline accumulation corresponding to high concentrations of Si, Mn, Fe, and Sr ions. The redox potential and dissolved oxygen concentration measurements supported the existence of layers in the nacre. The suspended materials in the drainage pond water comprised mainly of Si, Mn, and Fe elements, which were the same elements involved in microbial immobilization in the shell nacre during the summer of 2007. SEM-EDX analyses confirmed that the ions originated from diatoms, Siderocapsa sp. and Gallionella ferruginea in the stomach. There was little microbial immobilization of the ions in winter. The results suggested elemental immobilization in the layered shell nacre and indicated that Sinohyliopsis schlegeli fed on the ions, to grow the nacre during summer. Sinohyliopsis schlegeli with these biogenic oxides might contribute to the scavenging of heavy metals in natural water.

  11. Microbial Fluid-Rock Interactions in Chalk Samples and Salinity Factor in Divalent Ca2+ ions Release for Microbial Enhanced Oil Recovery Purposes

    DEFF Research Database (Denmark)

    Jimoh, Ismaila Adetunji; Rudyk, Svetlana Nikolayevna; Søgaard, Erik Gydesen

    2011-01-01

    In this study, laboratory experiments were performed on chalk samples from Danish sector of the North Sea to study microbial fluid-rock interactions with carbonate rock and to evaluate the dissolution of rock matrix (CaCO3). Result showed that the average concentration of Ca2+ ions after microbia...

  12. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold. Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  13. Factors controlling upper tropospheric relative humidity

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2004-03-01

    Full Text Available Factors controlling the distribution of relative humidity in the absence of clouds are examined, with special emphasis on relative humidity over ice (RHI under upper tropospheric and lower stratospheric conditions. Variations of temperature are the key determinant for the distribution of RHI, followed by variations of the water vapor mixing ratio. Multiple humidity modes, generated by mixing of different air masses, may contribute to the overall distribution of RHI, in particular below ice saturation. The fraction of air that is supersaturated with respect to ice is mainly determined by the distribution of temperature. The nucleation of ice in cirrus clouds determines the highest relative humdity that can be measured outside of cirrus clouds. While vertical air motion and ice microphysics determine the slope of the distributions of RHI, as shown in a separate study companion (Haag et al., 2003, clouds are not required to explain the main features of the distributions of RHI below the ice nucleation threshold.

    Key words. Atmospheric composition and structure (pressure, density and temperature; troposphere – composition and chemistry; general or miscellaneous

  14. Artificial soil microcosms: a tool for studying microbial autecology under controlled conditions.

    Science.gov (United States)

    Ellis, Richard J

    2004-02-01

    A novel artificial microcosm containing all the essential chemical components of soil, but with reduced heterogeneity and biological complexity, has been developed. Its utility for supporting realistic microbial populations was demonstrated and an example of how competing bacteria can be studied is illustrated.

  15. A study of microbial population dynamics associated with corrosion rates influenced by corrosion control materials

    NARCIS (Netherlands)

    Chang, Yu Jie; Hung, Chun Hsiung; Lee, Jyh Wei; Chang, Yi Tang; Lin, Fen Yu; Chuang, Chun Jie

    2015-01-01

    This research aims to analyze the variations of microbial community structure under anaerobic corrosive conditions, using molecular fingerprinting method. The effect of adding various materials to the environment on the corrosion mechanism has been discussed. In the initial experiment,

  16. Seasonal and episodic moisture controls on plant and microbial contributions to soil respiration.

    Science.gov (United States)

    Carbone, Mariah S; Still, Christopher J; Ambrose, Anthony R; Dawson, Todd E; Williams, A Park; Boot, Claudia M; Schaeffer, Sean M; Schimel, Joshua P

    2011-09-01

    Moisture inputs drive soil respiration (SR) dynamics in semi-arid and arid ecosystems. However, determining the contributions of root and microbial respiration to SR, and their separate temporal responses to periodic drought and water pulses, remains poorly understood. This study was conducted in a pine forest ecosystem with a Mediterranean-type climate that receives seasonally varying precipitation inputs from both rainfall (in the winter) and fog-drip (primarily in the summer). We used automated SR measurements, radiocarbon SR source partitioning, and a water addition experiment to understand how SR, and its separate root and microbial sources, respond to seasonal and episodic changes in moisture. Seasonal changes in SR were driven by surface soil water content and large changes in root respiration contributions. Superimposed on these seasonal patterns were episodic pulses of precipitation that determined the short-term SR patterns. Warm season precipitation pulses derived from fog-drip, and rainfall following extended dry periods, stimulated the largest SR responses. Microbial respiration dominated these SR responses, increasing within hours, whereas root respiration responded more slowly over days. We conclude that root and microbial respiration sources respond differently in timing and magnitude to both seasonal and episodic moisture inputs. These findings have important implications for the mechanistic representation of SR in models and the response of dry ecosystems to changes in precipitation patterns.

  17. Microbial controls on metal mobility under the low nutrient fluxes found throughout the subsurface

    International Nuclear Information System (INIS)

    Boult, Stephen; Hand, Victoria L.; Vaughan, David J.

    2006-01-01

    Laboratory simulations and field studies of the shallow subsurface have shown that microbes and their extracellular products can influence the mobility of toxic metals from waste disposal sites. Modelling the transport of contaminants in groundwater may, therefore, require the input of microbial ecology data in addition to geochemical data, thus increasing the costs and the uncertainty of predictions. However, whether microbial effects on contaminant mobility occur extensively in the natural subsurface is unknown because the conditions under which they have been observed hitherto are generally unrepresentative of the average subsurface environment. Here, we show that microbial activity affects the mobility of a toxic trace metal (Cu) under the relatively low nutrient fluxes that dominate subsurface systems. More particularly, we show that under these low nutrient conditions, microbes and microbial products can immobilize metal but may themselves be subject to subsequent mobilization, thus complicating the pattern of metal storage and release. Our results show that the capability of microbes in the subsurface to change both the capacity of porous media to store metal, and the behaviour of metal that is released, is not restricted to the well researched environments close to sites of waste disposal. We anticipate our simulations will be a starting point for generating input data for transport models, and specifying the mechanism of metal remobilisation in environments more representative of the subsurface generally

  18. Colon cancer controls versus population controls in case-control studies of occupational risk factors

    DEFF Research Database (Denmark)

    Kaerlev, Linda; Lynge, Elsebeth; Sabroe, Svend

    2004-01-01

    are interchangeable with the experience for population controls. Patient controls may even be preferable from population controls under certain conditions. In this study we examine if colon cancer patients can serve as surrogates for proper population controls in case-control studies of occupational risk factors...... about occupational, medical and life style conditions. RESULTS: No statistical significant difference for educational level, medical history or smoking status was seen between the two control groups. There was evidence of a higher alcohol intake, less frequent work as a farmer and less exposure...... to pesticides among colon cancer controls. CONCLUSIONS: Use of colon cancer controls may provide valid exposure estimates in studies of many occupational risk factors for cancer, but not for studies on exposure related to farming....

  19. Soil biochemical properties and microbial resilience in agroforestry systems: effects on wheat growth under controlled drought and flooding conditions.

    Science.gov (United States)

    Rivest, David; Lorente, Miren; Olivier, Alain; Messier, Christian

    2013-10-01

    Agroforestry is increasingly viewed as an effective means of maintaining or even increasing crop and tree productivity under climate change while promoting other ecosystem functions and services. This study focused on soil biochemical properties and resilience following disturbance within agroforestry and conventional agricultural systems and aimed to determine whether soil differences in terms of these biochemical properties and resilience would subsequently affect crop productivity under extreme soil water conditions. Two research sites that had been established on agricultural land were selected for this study. The first site included an 18-year-old windbreak, while the second site consisted in an 8-year-old tree-based intercropping system. In each site, soil samples were used for the determination of soil nutrient availability, microbial dynamics and microbial resilience to different wetting-drying perturbations and for a greenhouse pot experiment with wheat. Drying and flooding were selected as water stress treatments and compared to a control. These treatments were initiated at the beginning of the wheat anthesis period and maintained over 10 days. Trees contributed to increase soil nutrient pools, as evidenced by the higher extractable-P (both sites), and the higher total N and mineralizable N (tree-based intercropping site) found in the agroforestry compared to the conventional agricultural system. Metabolic quotient (qCO2) was lower in the agroforestry than in the conventional agricultural system, suggesting higher microbial substrate use efficiency in agroforestry systems. Microbial resilience was higher in the agroforestry soils compared to soils from the conventional agricultural system (windbreak site only). At the windbreak site, wheat growing in soils from agroforestry system exhibited higher aboveground biomass and number of grains per spike than in conventional agricultural system soils in the three water stress treatments. At the tree

  20. Microbial control of soil organic matter mineralization responses to labile carbon in subarctic climate change treatments.

    Science.gov (United States)

    Rousk, Kathrin; Michelsen, Anders; Rousk, Johannes

    2016-12-01

    Half the global soil carbon (C) is held in high-latitude systems. Climate change will expose these to warming and a shift towards plant communities with more labile C input. Labile C can also increase the rate of loss of native soil organic matter (SOM); a phenomenon termed 'priming'. We investigated how warming (+1.1 °C over ambient using open top chambers) and litter addition (90 g m -2  yr -1 ) treatments in the subarctic influenced the susceptibility of SOM mineralization to priming, and its microbial underpinnings. Labile C appeared to inhibit the mineralization of C from SOM by up to 60% within hours. In contrast, the mineralization of N from SOM was stimulated by up to 300%. These responses occurred rapidly and were unrelated to microbial successional dynamics, suggesting catabolic responses. Considered separately, the labile C inhibited C mineralization is compatible with previously reported findings termed 'preferential substrate utilization' or 'negative apparent priming', while the stimulated N mineralization responses echo recent reports of 'real priming' of SOM mineralization. However, C and N mineralization responses derived from the same SOM source must be interpreted together: This suggested that the microbial SOM-use decreased in magnitude and shifted to components richer in N. This finding highlights that only considering SOM in terms of C may be simplistic, and will not capture all changes in SOM decomposition. The selective mining for N increased in climate change treatments with higher fungal dominance. In conclusion, labile C appeared to trigger catabolic responses of the resident microbial community that shifted the SOM mining to N-rich components; an effect that increased with higher fungal dominance. Extrapolating from these findings, the predicted shrub expansion in the subarctic could result in an altered microbial use of SOM, selectively mining it for N-rich components, and leading to a reduced total SOM-use. © 2016 John Wiley

  1. Microbial Community Assessment in Wetlands for Water Pollution Control: Past, Present, and Future Outlook

    Directory of Open Access Journals (Sweden)

    Kela P. Weber

    2016-11-01

    Full Text Available The field of treatment wetlands (TWs is rapidly expanding and, arguably, is tasked with studying and understanding one of the most complex water treatment systems available. Microbial communities are generally considered to be responsible for the majority of wastewater constituent degradation in TWs. However, they are also known to be spatially heterogeneous, temporally dynamic, as well as structurally and functionally diverse. Presented here is a meta-analysis of all peer reviewed TW journal articles which utilized a microbial community assessment methodology over the period of 1988 to July 2016. A total of 1101 papers were reviewed, 512 from 1988 to 2012, 215 of which included a microbial community assessment aspect and were subsequently classified as representing past research, and 589 from 2013 to July 2016, 196 of which were classified as representing current TW microbial community research. In general, TW microbial community research has increased over time, with a marked surge in the past four years. Microbial community structure is currently the most commonly used methodological type followed by activity, enumeration and function, respectively. Areas of research focus included nitrogen transformations (156, organic degradation (33, and emerging contaminants (32, with general characterization studies also accounting for a significant proportion (243. Microbial communities from a range of TW systems have been investigated over the last four years with meso-scale (10–1000 L being the most commonly studied system size followed by large-scale (>100,000 L, micro-scale (<10 L, and pilot-scale (1000–100,000 L. Free water surface flow (SF, horizontal subsurface flow (HF, and vertical flow (VF systems are being studied in approximately equal proportions with the majority of studies focused on gaining fixed media/biofilm samples for analysis (rather than from the rhizosphere or interstitial water. Looking at efforts from a regional perspective

  2. Thermodynamic controls on the kinetics of microbial low-pH Fe(II) oxidation.

    Science.gov (United States)

    Larson, Lance N; Sánchez-España, Javier; Kaley, Bradley; Sheng, Yizhi; Bibby, Kyle; Burgos, William D

    2014-08-19

    Acid mine drainage (AMD) is a major worldwide environmental threat to surface and groundwater quality. Microbial low-pH Fe(II) oxidation could be exploited for cost-effective AMD treatment; however, its use is limited because of uncertainties associated with its rate and ability to remove Fe from solution. We developed a thermodynamic-based framework to evaluate the kinetics of low-pH Fe(II) oxidation. We measured the kinetics of low-pH Fe(II) oxidation at five sites in the Appalachian Coal Basin in the US and three sites in the Iberian Pyrite Belt in Spain and found that the fastest rates of Fe(II) oxidation occurred at the sites with the lowest pH values. Thermodynamic calculations showed that the Gibbs free energy of Fe(II) oxidation (ΔG(oxidation)) was also most negative at the sites with the lowest pH values. We then conducted two series of microbial Fe(II) oxidation experiments in laboratory-scale chemostatic bioreactors operated through a series of pH values (2.1-4.2) and found the same relationships between Fe(II) oxidation kinetics, ΔG(oxidation), and pH. Conditions that favored the fastest rates of Fe(II) oxidation coincided with higher Fe(III) solubility. The solubility of Fe(III) minerals, thus plays an important role on Fe(II) oxidation kinetics. Methods to incorporate microbial low-pH Fe(II) oxidation into active and passive AMD treatment systems are discussed in the context of these findings. This study presents a simplified model that describes the relationship between free energy and microbial kinetics and should be broadly applicable to many biogeochemical systems.

  3. Controlling accumulation of fermentation inhibitors in biorefinery recycle water using microbial fuel cells

    Directory of Open Access Journals (Sweden)

    Vishnivetskaya Tatiana A

    2009-04-01

    Full Text Available Abstract Background Microbial fuel cells (MFC and microbial electrolysis cells are electrical devices that treat water using microorganisms and convert soluble organic matter into electricity and hydrogen, respectively. Emerging cellulosic biorefineries are expected to use large amounts of water during production of ethanol. Pretreatment of cellulosic biomass results in production of fermentation inhibitors which accumulate in process water and make the water recycle process difficult. Use of MFCs to remove the inhibitory sugar and lignin degradation products from recycle water is investigated in this study. Results Use of an MFC to reduce the levels of furfural, 5-hydroxymethylfurfural, vanillic acid, 4-hydroxybenzaldehyde and 4-hydroxyacetophenone while simultaneously producing electricity is demonstrated here. An integrated MFC design approach was used which resulted in high power densities for the MFC, reaching up to 3700 mW/m2 (356 W/m3 net anode volume and a coulombic efficiency of 69%. The exoelectrogenic microbial consortium enriched in the anode was characterized using a 16S rRNA clone library method. A unique exoelectrogenic microbial consortium dominated by δ-Proteobacteria (50%, along with β-Proteobacteria (28%, α-Proteobacteria (14%, γ-Proteobacteria (6% and others was identified. The consortium demonstrated broad substrate specificity, ability to handle high inhibitor concentrations (5 to 20 mM with near complete removal, while maintaining long-term stability with respect to power production. Conclusion Use of MFCs for removing fermentation inhibitors has implications for: 1 enabling higher ethanol yields at high biomass loading in cellulosic ethanol biorefineries, 2 improved water recycle and 3 electricity production up to 25% of total biorefinery power needs.

  4. Efficacy of Moss as a Bioindicator of Heavy Metals When Controlling for Microbial Variables

    Science.gov (United States)

    Hall, K. M.; Atkinson, D. B.

    2017-12-01

    Interest in pollution has lead to the use of plants as indicators of particulate levels, acting as a cheaper, more widely dispersed resource than human manufactured alternatives. These biomonitors could provide accurate, current data across cities and in localized regions once the mechanism of accumulation is fully understood. One possible variable that could affect the efficacy of mosses as bioindicators of heavy metal absorption is the microbial colonies that thrive on the surface of these non vascular plants. Each micro organism has shown variance in absorption of heavy metals, leading to the question how much do the colonies contribute to measured variation? For this experiment samples of living mosses were collected from different trees in a region, each showing a different set of organisms growing on them. Measurements of cadmium were taken from a portion of the first samples, and second samples will be taken after dosing the rest of the living samples in a lab environment over time. Two of the mosses are being treated to limit microbial growth to compare to samples from the same tree. We hypothesize that there will be a significant difference either from one tree's absorption to the next, or between mosses from the same tree with limited growth due to the variation of microbial influence.

  5. Hydrogeological controls of variable microbial water quality in a complex subtropical karst system in Northern Vietnam

    Science.gov (United States)

    Ender, Anna; Goeppert, Nadine; Goldscheider, Nico

    2018-05-01

    Karst aquifers are particularly vulnerable to bacterial contamination. Especially in developing countries, poor microbial water quality poses a threat to human health. In order to develop effective groundwater protection strategies, a profound understanding of the hydrogeological setting is crucial. The goal of this study was to elucidate the relationships between high spatio-temporal variability in microbial contamination and the hydrogeological conditions. Based on extensive field studies, including mapping, tracer tests and hydrochemical analyses, a conceptual hydrogeological model was developed for a remote and geologically complex karst area in Northern Vietnam called Dong Van. Four different physicochemical water types were identified; the most important ones correspond to the karstified Bac Son and the fractured Na Quan aquifer. Alongside comprehensive investigation of the local hydrogeology, water quality was evaluated by analysis for three types of fecal indicator bacteria (FIB): Escherichia coli, enterococci and thermotolerant coliforms. The major findings are: (1) Springs from the Bac Son formation displayed the highest microbial contamination, while (2) springs that are involved in a polje series with connections to sinking streams were distinctly more contaminated than springs with a catchment area characterized by a more diffuse infiltration. (3) FIB concentrations are dependent on the season, with higher values under wet season conditions. Furthermore, (4) the type of spring capture also affects the water quality. Nevertheless, all studied springs were faecally impacted, along with several shallow wells within the confined karst aquifer. Based on these findings, effective protection strategies can be developed to improve groundwater quality.

  6. Risk factors, microbiological findings, and clinical outcomes in cases of microbial keratitis admitted to a tertiary referral center in ireland.

    LENUS (Irish Health Repository)

    Saeed, Ayman

    2012-02-01

    AIM: To identify the risk factors for, and to report the microbiological findings and clinical outcomes of, severe microbial keratitis (MK). METHODS: This was a retrospective study of all cases of presumed MK admitted to a tertiary referral center over a 2-year period (September 2001 to August 2003). Data recorded included demographic data, details relating to possible risk factors, results of microbiological studies, clinical findings at presentation, and clinical and visual outcomes. RESULTS: Ninety patients were admitted with a diagnosis of presumed MK during the study period. The mean age of patients was 45 +\\/- 32 years, and the male to female ratio was 47:43 (52.2%:47.7%). Predisposing risk factors for MK included contact lens wear (37; 41.1%), anterior segment disease (19; 21.1%), ocular trauma (13; 14.4%), systemic disease (5; 5.6%), and previous ocular surgery (1; 1.1%). Cultured organisms included gram-negative bacteria (17; 51.5%), gram-positive bacteria (11, 33.3%), acanthamoeba (2; 6.1%), and fungi (1; 3%). Visual acuity improved significantly after treatment [mean best-corrected visual acuity (+\\/-standard deviation) at presentation: 0.76 (+\\/-0.11); mean best-corrected visual acuity at last follow-up: 0.24 (+\\/-0.07); P < 0.001]. Secondary surgical procedures were required in 18 (20%) cases, and these included punctal cautery (1; 1.1%), tissue glue repair of corneal perforation (2; 2.2%), tarsorrhaphy (9; 9.9%), Botulinum toxin-induced ptosis (1; 1.1%), penetrating keratoplasty (3; 3.3%), and evisceration (2; 2.2%). CONCLUSIONS: Contact lens wear remains a significant risk factor for severe MK. MK remains a threat to vision and to the eye, but the majority of cases respond to prompt and appropriate antimicrobial therapy.

  7. Development of biocontrol agents from food microbial isolates for controlling post-harvest peach brown rot caused by Monilinia fructicola.

    Science.gov (United States)

    Zhou, Ting; Schneider, Karin E; Li, Xiu-Zhen

    2008-08-15

    An unconventional strategy of screening food microbes for biocontrol activity was used to develop biocontrol agents for controlling post-harvest peach brown rot caused by Monilinia fructicola. Forty-four microbial isolates were first screened for their biocontrol activity on apple fruit. Compared with the pathogen-only check, seven of the 44 isolates reduced brown rot incidence by >50%, including four bacteria: Bacillus sp. C06, Lactobacillus sp. C03-b and Bacillus sp. T03-c, Lactobacillus sp. P02 and three yeasts: Saccharomyces delbrueckii A50, S. cerevisiae YE-5 and S. cerevisiae A41. Eight microbial isolates were selected for testing on peaches by wound co-inoculation with mixtures of individual microbial cultures and conidial suspension of M. fructicola. Only two of them showed significant biocontrol activity after five days of incubation at 22 degrees C. Bacillus sp. C06 suppressed brown rot incidence by 92% and reduced lesion diameter by 88% compared to the pathogen-only check. Bacillus sp.T03-c reduced incidence and lesion diameter by 40% and 62%, respectively. The two isolates were compared with Pseudomonas syringae MA-4, a biocontrol agent for post-harvest peach diseases, by immersing peaches in an aliquot containing individual microbial isolates and the pathogen conidia. Treatments with isolates MA-4, C06 and T03-c significantly controlled brown rot by 91, 100, and 100% respectively. However, only isolates MA-4 and C06 significantly reduced brown rot by 80% and 15%, respectively when bacterial cells alone were applied. On naturally infected peaches, both the bacterial culture and its cell-free filtrate of the isolate C06 significantly controlled peach decay resulting in 77 and 90% reduction, respectively, whereas the treatment using only the bacterial cells generally had no effect. Isolate C06 is a single colony isolate obtained from a mesophilic cheese starter, and has been identified belonging to Bacillus amyloliquefaciens. The results have clearly

  8. Factors influencing the profitability of optimizing control systems

    International Nuclear Information System (INIS)

    Broussaud, A.; Guyot, O.

    1999-01-01

    Optimizing control systems supplement conventional Distributed Control Systems and Programmable Logic Controllers. They continuously implement set points, which aim at maximizing the profitability of plant operation. They are becoming an integral part of modern mineral processing plants. This trend is justified by economic considerations, optimizing control being among the most cost-effective methods of improving metallurgical plant performance. The paper successively analyzes three sets of factors, which influence the profitability of optimizing control systems, and provides guidelines for analyzing the potential value of an optimizing control system at a given operation: external factors, such as economic factors and factors related to plant feed; features of the optimizing control system; and subsequent maintenance of the optimizing control system. It is shown that pay back times for optimization control projects are typically measured in days. The OCS software used by the authors for their applications is described briefly. (author)

  9. Microbial accumulation of uranium

    International Nuclear Information System (INIS)

    Zhang Wei; Dong Faqin; Dai Qunwei

    2005-01-01

    The mechanism of microbial accumulation of uranium and the effects of some factors (including pH, initial uranium concentration, pretreatment of bacteria, and so on) on microbial accumulation of uranium are discussed briefly. The research direction and application prospect are presented. (authors)

  10. Host-derived, pore-forming toxin-like protein and trefoil factor complex protects the host against microbial infection.

    Science.gov (United States)

    Xiang, Yang; Yan, Chao; Guo, Xiaolong; Zhou, Kaifeng; Li, Sheng'an; Gao, Qian; Wang, Xuan; Zhao, Feng; Liu, Jie; Lee, Wen-Hui; Zhang, Yun

    2014-05-06

    Aerolysins are virulence factors belonging to the bacterial β-pore-forming toxin superfamily. Surprisingly, numerous aerolysin-like proteins exist in vertebrates, but their biological functions are unknown. βγ-CAT, a complex of an aerolysin-like protein subunit (two βγ-crystallin domains followed by an aerolysin pore-forming domain) and two trefoil factor subunits, has been identified in frogs (Bombina maxima) skin secretions. Here, we report the rich expression of this protein, in the frog blood and immune-related tissues, and the induction of its presence in peritoneal lavage by bacterial challenge. This phenomena raises the possibility of its involvement in antimicrobial infection. When βγ-CAT was administrated in a peritoneal infection model, it greatly accelerated bacterial clearance and increased the survival rate of both frogs and mice. Meanwhile, accelerated Interleukin-1β release and enhanced local leukocyte recruitments were determined, which may partially explain the robust and effective antimicrobial responses observed. The release of interleukin-1β was potently triggered by βγ-CAT from the frog peritoneal cells and murine macrophages in vitro. βγ-CAT was rapidly endocytosed and translocated to lysosomes, where it formed high molecular mass SDS-stable oligomers (>170 kDa). Lysosomal destabilization and cathepsin B release were detected, which may explain the activation of caspase-1 inflammasome and subsequent interleukin-1β maturation and release. To our knowledge, these results provide the first functional evidence of the ability of a host-derived aerolysin-like protein to counter microbial infection by eliciting rapid and effective host innate immune responses. The findings will also largely help to elucidate the possible involvement and action mechanisms of aerolysin-like proteins and/or trefoil factors widely existing in vertebrates in the host defense against pathogens.

  11. Invasion in microbial communities: Role of community composition and assembly processes

    DEFF Research Database (Denmark)

    Kinnunen, Marta

    of microbial community assembly. Biotic factors include interactions between different microbial groups as well as the community response to alien species – invaders. Microbial invasions can have significant effects on the composition and functioning of resident communities. There is, however, lack......Microbes contribute to all biogeochemical cycles on earth and are responsible for key biological processes that support the survival of plants and animals. There is increased interest in controlling and managing microbial communities in different ecosystems in order to make targeted microbiological...... processes more effective. In order to manage microbial communities, it is essential to understand the factors that shape and influence microbial community composition. In addition to abiotic factors, such as environmental conditions and resource availability, biotic factors also shape the dynamics...

  12. Viral infections as controlling factors for the deep biosphere? (Invited)

    Science.gov (United States)

    Engelen, B.; Engelhardt, T.; Sahlberg, M.; Cypionka, H.

    2009-12-01

    The marine deep biosphere represents the largest biotope on Earth. Throughout the last years, we have obtained interesting insights into its microbial community composition. However, one component that was completely overlooked so far is the viral inventory of deep-subsurface sediments. While viral infections were identified to have a major impact on the benthic microflora of deep-sea surface sediments (Danavaro et al. 2008), no studies were performed on deep-biosphere samples, so far. As grazers probably play only a minor role in anoxic and highly compressed deep sediments, viruses might be the main “predators” for indigenous microorganisms. Furthermore, the release of cell components, called “the viral shunt”, could have a major impact on the deep biosphere in providing labile organic compounds to non-infected microorganisms in these generally nutrient depleted sediments. However, direct counting of viruses in sediments is highly challenging due to the small size of viruses and the high background of small particles. Even molecular surveys using “universal” PCR primers that target phage-specific genes fail due to the vast phage diversity. One solution for this problem is the lysogenic viral life cycle as many bacteriophages integrate their DNA into the host genome. It is estimated that up to 70% of cultivated bacteria contain prophages within their genome. Therefore, culture collections (Batzke et al. 2007) represent an archive of the viral composition within the respective habitat. These prophages can be induced to become free phage particles in stimulation experiments in which the host cells are set under certain stress situations such as a treatment with UV exposure or DNA-damaging antibiotics. The study of the viral component within the deep biosphere offers to answer the following questions: To which extent are deep-biosphere populations controlled by viral infections? What is the inter- and intra-specific diversity and the host-specific viral

  13. Factors controlling superelastic damping capacity of SMAs

    Czech Academy of Sciences Publication Activity Database

    Heller, Luděk; Šittner, Petr; Pilch, Jan; Landa, Michal

    2009-01-01

    Roč. 18, 5-6 (2009), 603-611 ISSN 1059-9495 Institutional research plan: CEZ:AV0Z10100520; CEZ:AV0Z20760514 Keywords : shape memory alloys * superelastic damping * thermomechanical testing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.592, year: 2009

  14. A microbial-mineralization-inspired approach for synthesis of manganese oxide nanostructures with controlled oxidation states and morphologies

    Energy Technology Data Exchange (ETDEWEB)

    Oba, Manabu; Oaki, Yuya; Imai, Hiroaki [Department of Applied Chemistry, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan)

    2010-12-21

    Manganese oxide nanostructures are synthesized by a route inspired by microbial mineralization in nature. The combination of organic molecules, which include antioxidizing and chelating agents, facilitates the parallel control of oxidation states and morphologies in an aqueous solution at room temperature. Divalent manganese hydroxide (Mn(OH){sub 2}) is selectively obtained as a stable dried powder by using a combination of ascorbic acid as an antioxidizing agent and other organic molecules with the ability to chelate to manganese ions. The topotactic oxidation of the resultant Mn(OH){sub 2} leads to the selective formation of trivalent manganese oxyhydroxide ({beta}-MnOOH) and trivalent/tetravalent sodium manganese oxide (birnessite, Na{sub 0.55}Mn{sub 2}O{sub 4}.1.5H{sub 2}O). For microbial mineralization in nature, similar synthetic routes via intermediates have been proposed in earlier works. Therefore, these synthetic routes, which include in the present study the parallel control over oxidation states and morphologies of manganese oxides, can be regarded as new biomimetic routes for synthesis of transition metal oxide nanostructures. As a potential application, it is demonstrated that the resultant {beta}-MnOOH nanostructures perform as a cathode material for lithium ion batteries. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  15. Assessing effects of the entomopathogenic fungus Metarhizium brunneum on soil microbial communities in Agriotes spp. biological pest control.

    Science.gov (United States)

    Mayerhofer, Johanna; Eckard, Sonja; Hartmann, Martin; Grabenweger, Giselher; Widmer, Franco; Leuchtmann, Adrian; Enkerli, Jürg

    2017-10-01

    The release of large quantities of microorganisms to soil for purposes such as pest control or plant growth promotion may affect the indigenous soil microbial communities. In our study, we investigated potential effects of Metarhizium brunneum ART2825 on soil fungi and prokaryota in bulk soil using high-throughput sequencing of ribosomal markers. Different formulations of this strain, and combinations of the fungus with garlic as efficacy-enhancing agent, were tested over 4 months in a pot and a field experiment carried out for biological control of Agriotes spp. in potatoes. A biocontrol effect was observed only in the pot experiment, i.e. the application of FCBK resulted in 77% efficacy. Colony counts combined with genotyping and marker sequence abundance confirmed the successful establishment of the applied strain. Only the formulated applied strain caused small shifts in fungal communities in the pot experiment. Treatment effects were in the same range as the effects caused by barley kernels, the carrier of the FCBK formulation and temporal effects. Garlic treatments and time affected prokaryotic communities. In the field experiment, only spatial differences affected fungal and prokaryotic communities. Our findings suggest that M. brunneum may not adversely affect soil microbial communities. © FEMS 2017.

  16. Abiogenic and Microbial Controls on Volatile Fatty Acids in Precambrian Crustal Fracture Waters

    Science.gov (United States)

    McDermott, J. M.; Heuer, V.; Tille, S.; Moran, J.; Slater, G.; Sutcliffe, C. N.; Glein, C. R.; Hinrichs, K. U.; Sherwood Lollar, B.

    2015-12-01

    Saline fracture waters within the Precambrian Shield rocks of Canada and South Africa have been sequestered underground over geologic timescales up to 1.1-1.8 Ga [1, 2]. These fluids are rich in H2 derived from radiolysis and hydration of mafic and ultramafic rocks [1, 2, 3] and host a low-biomass, low-diversity microbial ecosystem at some sites [2]. The abiogenic or biogenic nature of geochemical processes has important implications for bioavailable carbon sources and the role played by abiotic organic synthesis in sustaining a chemosynthetic deep biosphere. Volatile fatty acids (VFAs) are simple carboxylic acids that may support microbial communities in such environments, such as those found in terrestrial [4] and deep-sea [5] hot springs. We present abundance and δ13C analysis for VFAs in a spectrum of Canadian Shield fluids characterized by varying dissolved H2, CH4, and C2+ n-alkane compositions. Isotope mass balance indicates that microbially mediated fermentation of carbon-rich graphitic sulfides may produce the elevated levels of acetate (39-273 μM) found in Birchtree and Thompson mine. In contrast, thermodynamic considerations and isotopic signatures of the notably higher acetate (1.2-1.9 mM), as well as formate and propionate abundances (371-816 μM and 20-38 μM, respectively) found at Kidd Creek mine suggest a role for abiogenic production via reduction of dissolved inorganic carbon with H2 for formate, and oxidation of C2+ n-alkanes for acetate and propionate, along with possible microbial cycling. VFAs comprise the bulk of dissolved and total organic carbon in the mines surveyed, and as such represent a potential key substrate for life. [1] Holland et al. (2013) Nature 497: 367-360. [2] Lin et al. (2006) Science 314: 479-482. [3] Sherwood Lollar et al. (2014) Nature 516: 379-382. [4] Windman et al. (2007) Astrobiology 7(6): 873-890. [5] Lang et al. (2010) Geochim. Cosmochim. Acta 92: 82-99.

  17. Microbial biofilms control economic metal mobility in an acid-sulfate hydrothermal system

    Science.gov (United States)

    Phillips-Lander, C. M.; Roberts, J. A.; Hernandez, W.; Mora, M.; Fowle, D. A.

    2012-12-01

    Trace metal cycling in hydrothermal systems has been the subject of a variety of geochemical and economical geology studies. Typically in these settings these elements are sequestered in sulfide and oxide mineral fractions, however in near-surface low-temperature environments organic matter and microorganisms (typically in mats) have been implicated in their mobility through sorption. Here we specifically examine the role of microbial biofilms on metal partitioning in an acid-sulfate hydrothermal system. We studied the influence of microorganisms and microbial biofilms on trace metal adsorption in Pailas de Aguas I, an acid-sulfate hot spring on the southwest flank of Rincon de la Vieja, a composite stratovolcano in the Guanacaste Province, Costa Rica. Spring waters contain high suspended loads, and are characterized by high T (79.6-89.3oC), low pH (2.6-4), and high ionic strengths (I= 0.5-0.8). Waters contain high concentrations of the biogeochemically active elements Fe (4-6 mmol/l) and SO42- (38 mmol/l), but PO43- are below detection limits (bdl). Silver, Ni, and Mo concentrations are bdl; however other trace metals are present in solution in concentrations of 0.1-0.2 mg/l Cd, 0.2-0.4 mg/l Cr and V, 0.04-1 mg/l Cu,. Preliminary 16S rRNA analyses of microorganisms in sediments reveal several species of algae, including Galderia sp., Cyanidium sp, γ-proteobacteria, Acidithiobacillus caldus, Euryarcheota, and methanogens. To evaluate microbial biofilms' impact on trace metal mobility we analyzed a combination of suspended, bulk and biofilm associated sediment samples via X-ray diffraction (XRD) and trace element sequential extractions (SE). XRD analysis indicated all samples were primarily composed of Fe/Al clay minerals (nontronite, kaolinite), 2- and 6-line ferrihydrite, goethite, and hematite, quartz, and opal-α. SE showed the highest concentrations of Cu, Mo, and V were found in the suspended load. Molybdenum was found primarily in the residual and organic

  18. Anti - microbial resistance stratified by risk factor among Escherichia coli strains isolated from the urinary tract at a rural clinic in Central India

    Directory of Open Access Journals (Sweden)

    Chatterjee B

    2009-01-01

    Full Text Available Background: The failure of empirical therapy is frequently observed, even in community-acquired urinary tract infections. We, therefore, conducted a prospective, clinic-based study in 2004-2005 to document anti-microbial resistance rates and correlate them with possible risk factors to assist empirical decision-making. Materials and Methods: Symptomatic patients with pyuria underwent urine culture. Isolates were identified using standard methods and anti-microbial resistance was determined by disk-diffusion. Ultrasonography was used to detect complicating factors. Patients were stratified by the presence of complicating factors and history of invasive procedures for comparison of resistance rates. Statistical Method Used: Chi-square or Fisher exact tests, as appropriate. Results: There were 156 E. coli isolates, of which 105 were community-acquired. Twenty-three community-acquired isolates were from patients with complicating factors while 82 were from patients without any. Fifty-one isolates were from patients who had recently undergone invasive procedures on the urinary tract. Thirty-two community-acquired isolates from reproductive-age women without apparent complicating factors had resistance rates of 50% or above against tetracyclines, Co-trimoxazole, aminopenicillins, Nalidixic acid, Ciprofloxacin and 1 st generation cephalosporins. Resistance rates were significantly higher among isolates from patients subjected to invasive procedures, except against Co-trimoxazole, tetracyclines and Amikacin. Conclusion: High rates of anti-microbial resistance in community-acquired uropathogens have made antimicrobial sensitivity testing necessary even in a rural, primary-care setting.

  19. Oral Microbial Shift: Factors affecting the Microbiome and Prevention of Oral Disease.

    Science.gov (United States)

    Dagli, Namrata; Dagli, Rushabh; Darwish, Shrouq; Baroudi, Kusai

    2016-01-01

    Recently, oral microbiome has gained popularity among scientists. Microorganisms are no longer considered as disease-producing pathogens, rather they are now considered as partners of human in maintaining health. Since ancient times, changes in our lifestyle have affected our microbiome and the balance with their human host has been perturbed. The present review includes the description about factors affecting oral microbiome and establishing symbiosis with the human host so that they contribute in maintaining health rather than eliciting diseases. A comprehensive literature search was performed on databases such as Google Scholar, PubMed and Medline until April 2015. First, articles were selected on the basis of their titles and then abstracts were screened and unwanted articles were excluded. Articles obtained from all the databases were checked and duplicate articles were removed. Articles obtained from various databases: PubMed = 35, Google Scholar=8. Out of these 43 articles, total 29 articles were finally selected for this review. The published literature suggests that the modern oral microbiome is less biodiverse, and possess more pathogenic bacterial species and lesser beneficial bacteria. The possible factors mainly responsible for this shift in microbiome were found to be change in diet, industrial revolution and indiscriminate use of antibiotics. Various changes in lifestyles have affected oral microbiome adversely and perturb the symbiosis between the microbiome and their hosts. The present oral microbiome is found to be less diverse and more pathogenic. The present review may be helpful in understanding the relationship between the microbiome and their human hosts so that microbiome contributes in maintaining healthy state of the body.

  20. HUMAN FACTORS GUIDANCE FOR CONTROL ROOM EVALUATION

    International Nuclear Information System (INIS)

    OHARA, J.; BROWN, W.; STUBLER, W.; HIGGINS, J.; WACHTEL, J.; PERSENSKY, J.J.

    2000-01-01

    The Human-System Interface Design Review Guideline (NUREG-0700, Revision 1) was developed by the US Nuclear Regulatory Commission (NRC) to provide human factors guidance as a basis for the review of advanced human-system interface technologies. The guidance consists of three components: design review procedures, human factors engineering guidelines, and a software application to provide design review support called the ''Design Review Guideline.'' Since it was published in June 1996, Rev. 1 to NUREG-0700 has been used successfully by NRC staff, contractors and nuclear industry organizations, as well as by interested organizations outside the nuclear industry. The NRC has committed to the periodic update and improvement of the guidance to ensure that it remains a state-of-the-art design evaluation tool in the face of emerging and rapidly changing technology. This paper addresses the current research to update of NUREG-0700 based on the substantial work that has taken place since the publication of Revision 1

  1. Factors Affecting Sustainable Animal Trypanosomosis Control in ...

    African Journals Online (AJOL)

    trypanosomiasis control in parts of Kaduna State within the sub- humid savannah ... livestock farmers in planning and implementation. Across ... help to ensure a better management of livestock in tsetse fly infested areas with minimal loses in .... market and administered by them. This drug ... Table 2 shows the analysis of.

  2. What factors control dimerization of coniferyl alcohol?

    Science.gov (United States)

    Carl J. Houtman

    1999-01-01

    Data suggest that the dimerization of coniferyl alcohol is not under thermodynamic control. In this study, molecular dynamics calculations were used to estimate the effect of the solvent environment. In water, the coniferyl alcohol radicals were forced to associate by the formation of a solvent cage. In glycerol, the solvent cage effect appeared to be absent. These...

  3. Soft-Starting Power-Factor Motor Controller

    Science.gov (United States)

    Nola, F. J.

    1983-01-01

    Three-phase power-factor controller with soft start is based on earlier version that does not control starting transients. Additional components serve to turn off "run" command signal and substitute gradual startup command signal during preset startup interval. Improved controller reduces large current surge that usually accompanies starting. Controller applies power smoothly, without causing motor vibrations.

  4. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    Kristine L. Lowe; Bill W. Bogan; Wendy R. Sullivan; Kristine Mila H. Cruz; Brigid M. Lamb; John J. Kilbane II

    2004-07-30

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Previous testing indicated that the growth, and the metal corrosion caused by pure cultures of sulfate reducing bacteria were inhibited by hexane extracts of some pepper plants. This quarter tests were performed with mixed bacterial cultures obtained from natural gas pipelines. Treatment with the pepper extracts affected the growth and metabolic activity of the microbial consortia. Specifically, the growth and metabolism of sulfate reducing bacteria was inhibited. The demonstration that pepper extracts can inhibit the growth and metabolism of sulfate reducing bacteria in mixed cultures is a significant observation validating a key hypothesis of the project. Future tests to determine the effects of pepper extracts on mature/established biofilms will be performed next.

  5. Bi-layered nanocomposite bandages for controlling microbial infections and overproduction of matrix metalloproteinase activity.

    Science.gov (United States)

    Anjana, J; Mohandas, Annapoorna; Seethalakshmy, S; Suresh, Maneesha K; Menon, Riju; Biswas, Raja; Jayakumar, R

    2018-04-15

    Chronic diabetic wounds is characterised by increased microbial contamination and overproduction of matrix metalloproteases that would degrade the extracellular matrix. A bi-layer bandage was developed, that promotes the inhibition of microbial infections and matrix metalloprotease (MMPs) activity. Bi-layer bandage containing benzalkonium chloride loaded gelatin nanoparticles (BZK GNPs) in chitosan-Hyaluronic acid (HA) as a bottom layer and sodium alendronate containing chitosan as top layer was developed. We hypothesized that the chitosan-gelatin top layer with sodium alendronate could inhibit the MMPs activity, whereas the chitosan-HA bottom layer with BZK GNPs (240±66nm) would enable the elimination of microbes. The porosity, swelling and degradation nature of the prepared Bi-layered bandage was studied. The bottom layer could degrade within 4days whereas the top layer remained upto 7days. The antimicrobial activity of the BZK NPs loaded bandage was determined using normal and clinical strains. Gelatin zymography shows that the proteolytic activity of MMP was inhibited by the bandage. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. A controlled comparison of the BacT/ALERT® 3D and VIRTUO™ microbial detection systems.

    Science.gov (United States)

    Totty, H; Ullery, M; Spontak, J; Viray, J; Adamik, M; Katzin, B; Dunne, W M; Deol, P

    2017-10-01

    The performance of the next-generation BacT/ALERT® VIRTUO™ Microbial Detection System (VIRTUO™, bioMérieux Inc., Hazelwood, MO) was compared to the BacT/ALERT® 3D Microbial Detection System (3D, bioMérieux Inc., Durham, NC) using BacT/ALERT® FA Plus (FA Plus), BacT/ALERT® PF Plus (PF Plus), BacT/ALERT® FN Plus (FN Plus), BacT/ALERT® Standard Aerobic (SA), and BacT/ALERT® Standard Anaerobic (SN) blood culture bottles (bioMérieux Inc., Durham, NC). A seeded limit of detection (LoD) study was performed for each bottle type in both systems. The LoD studies demonstrated that both systems were capable of detecting organisms at nearly identical levels [detection (TTD) between the systems using a panel of clinically relevant microorganisms inoculated at or near the LoD with 0, 4, or 10 mL of healthy human blood. VIRTUO™ exhibited a faster TTD by an average of 3.5 h, as well as demonstrated a significantly improved detection rate of 99.9% compared to 98.8% with 3D (p-value <0.05).

  7. Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem

    Directory of Open Access Journals (Sweden)

    Kevin M. Geyer

    2017-07-01

    Full Text Available Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability and geochemical severity (e.g., pH, electrical conductivity. In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 μmol O2/m2/s in the most arid soils to an average of 6.97 μmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.

  8. Characterization and control of the microbial community affiliated with copper or aluminum heat exchangers of HVAC systems.

    Science.gov (United States)

    Schmidt, Michael G; Attaway, Hubert H; Terzieva, Silva; Marshall, Anna; Steed, Lisa L; Salzberg, Deborah; Hamoodi, Hameed A; Khan, Jamil A; Feigley, Charles E; Michels, Harold T

    2012-08-01

    Microbial growth in heating ventilation and air-conditioning (HVAC) systems with the subsequent contamination of indoor air is of increasing concern. Microbes and the subsequent biofilms grow easily within heat exchangers. A comparative study where heat exchangers fabricated from antimicrobial copper were evaluated for their ability to limit microbial growth was conducted using a full-scale HVAC system under conditions of normal flow rates using single-pass outside air. Resident bacterial and fungal populations were quantitatively assessed by removing triplicate sets of coupons from each exchanger commencing the fourth week after their installation for the next 30 weeks. The intrinsic biofilm associated with each coupon was extracted and characterized using selective and differential media. The predominant organisms isolated from aluminum exchangers were species of Methylobacterium of which at least three colony morphologies and 11 distinct PFGE patterns we found; of the few bacteria isolated from the copper exchangers, the majority were species of Bacillus. The concentrations and type of bacteria recovered from the control, aluminum, exchangers were found to be dependent on the type of plating media used and were 11,411-47,257 CFU cm(-2) per coupon surface. The concentration of fungi was found to average 378 CFU cm(-2). Significantly lower concentrations of bacteria, 3 CFU cm(-2), and fungi, 1 CFU cm(-2), were recovered from copper exchangers regardless of the plating media used. Commonly used aluminum heat exchangers developed stable, mixed, bacterial/fungal biofilms in excess of 47,000 organisms per cm(2) within 4 weeks of operation, whereas the antimicrobial properties of metallic copper were able to limit the microbial load affiliated with the copper heat exchangers to levels 99.97 % lower during the same time period.

  9. Human factors methods for nuclear control room design. Volume I. Human factors enhancement of existing nuclear control rooms. Final report

    International Nuclear Information System (INIS)

    Seminara, J.L.; Seidenstein, S.; Eckert, S.K.; Smith, D.L.

    1979-11-01

    Human factors engineering is an interdisciplinary specialty concerned with influencing the design of equipment systems, facilities, and operational environments to promote safe, efficient, and reliable operator performance. Human factors approaches were applied in the design of representative nuclear power plant control panels. First, methods for upgrading existing operational control panels were examined. Then, based on detailed human factors analyses of operator information and control requirements, designs of reactor, feedwater, and turbine-generator control panels were developed to improve the operator-control board interface, thereby reducing the potential for operator errors. In addition to examining present-generation concepts, human factors aspects of advanced systems and of hybrid combinations of advanced and conventional designs were investigated. Special attention was given to warning system designs. Also, a survey was conducted among control board designers to (1) develop an overview of design practices in the industry, and (2) establish appropriate measures leading to a more systematic concern for human factors in control board design

  10. Searching for the gut microbial contributing factors to social behavior in rodent models of autism spectrum disorder.

    Science.gov (United States)

    Needham, Brittany D; Tang, Weiyi; Wu, Wei-Li

    2018-05-01

    Social impairment is one of the major symptoms in multiple psychiatric disorders, including autism spectrum disorder (ASD). Accumulated studies indicate a crucial role for the gut microbiota in social development, but these mechanisms remain unclear. This review focuses on two strategies adopted to elucidate the complicated relationship between gut bacteria and host social behavior. In a top-down approach, researchers have attempted to correlate behavioral abnormalities with altered gut microbial profiles in rodent models of ASD, including BTBR mice, maternal immune activation (MIA), maternal valproic acid (VPA) and maternal high-fat diet (MHFD) offspring. In a bottom-up approach, researchers use germ-free (GF) animals, antibiotics, probiotics or pathogens to manipulate the intestinal environment and ascertain effects on social behavior. The combination of both approaches will hopefully pinpoint specific bacterial communities that control host social behavior. Further discussion of how brain development and circuitry is impacted by depletion of gut microbiota is also included. The converging evidence strongly suggests that gut microbes affect host social behavior through the alteration of brain neural circuits. Investigation of intestinal microbiota and host social behavior will unveil any bidirectional communication between the gut and brain and provide alternative therapeutic targets for ASD. © 2018 Wiley Periodicals, Inc. Develop Neurobiol 78: 474-499, 2018. © 2018 Wiley Periodicals, Inc.

  11. Control of Cellular Morphology by Mechanical Factors

    Science.gov (United States)

    Thoumine, Olivier

    1996-11-01

    This short review deals with the influence of mechanical factors on eucaryotic cell morphology and structure. We classify these factors into two types: i) external forces (e.g. gravitational forces or hemodynamic stresses), which when applied experimentally allow characterization of passive mechanical properties; and ii) internal forces, e.g. generated by molecular motors or polymerization processes. Perturbation of one or more of these forces induces significant changes in cell shape, cytoskeleton and pericellular matrix organization. We describe these phenomena in view of current models. Cette brève revue traite de l'influence des facteurs mécaniques sur la morphologie et la structure des cellules eucaryotes. Nous classifions ces facteurs en deux catégories : i) les forces externes (par exemple les forces de gravitation et les contraintes hèmodynamiques) qui, imposées in vitro, permettent de caractériser les propriétés mécaniques passives ; et ii) les forces internes, par exemple celles générées par les moteurs moléculaires ou les processus de polymérisation. La perturbation de l'une ou de l'autre de ces forces provoque des changements significatifs de la morphologie cellulaire ainsi que l'organisation du cytosquelette et de la matrice péricellulaire. Nous décrivons ces phénomènes en fonction de modèles existants.

  12. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

    The long term safety and integrity of radioactive waste disposal sites proposed for use by Ontario Hydro may be affected by the release of radioactive gases. Microbes mediate the primary pathways of waste degradation and hence an assessment of their potential to produce gaseous end products from the breakdown of low level waste was performed. Due to a number of unknown variables, assumptions were made regarding environmental and waste conditions that controlled microbial activity; however, it was concluded that 14 C and 3 H would be produced, albeit over a long time scale of about 1500 years for 14 C in the worst case situation

  13. Temperature Dependence of Factors Controlling Isoprene Emissions

    Science.gov (United States)

    Duncan, Bryan N.; Yoshida, Yasuko; Damon, Megan R.; Douglass, Anne R.; Witte, Jacquelyn C.

    2009-01-01

    We investigated the relationship of variability in the formaldehyde (HCHO) columns measured by the Aura Ozone Monitoring Instrument (OMI) to isoprene emissions in the southeastern United States for 2005-2007. The data show that the inferred, regional-average isoprene emissions varied by about 22% during summer and are well correlated with temperature, which is known to influence emissions. Part of the correlation with temperature is likely associated with other causal factors that are temperature-dependent. We show that the variations in HCHO are convolved with the temperature dependence of surface ozone, which influences isoprene emissions, and the dependence of the HCHO column to mixed layer height as OMI's sensitivity to HCHO increases with altitude. Furthermore, we show that while there is an association of drought with the variation in HCHO, drought in the southeastern U.S. is convolved with temperature.

  14. Efficacy of wild plant in combination with microbial antagonists for the control of root rot fungi on mungbean and cowpea

    International Nuclear Information System (INIS)

    Ikram, N.; Dawar, S.

    2015-01-01

    Present work was carried out to investigate the efficacy of Aerva javanica in combination with different microbial antagonists namely Rhizobium meliloti, Pseudomonas aeruginosa, Trichoderma harzianum and Aspergillus niger. Soil amended with A. javanica stem, leaves, flower powder at the rate1% w/w and seeds of cowpea (Vigna unguiculata L.) and mungbean (Vigna radiata L.) were coated with microbial antagonists for the control of root infecting fungi like Macrophomina phaseolina (Tassi) Goid, Fusarium spp. and Rhizoctonia solani Kiihn. Infection of M. phaseolina and R. solani were completely suppressed when seeds were coated with P. aeruginosa, T. harzianum, A. niger, R. meliloti and A. javanica leaves powder mixed in soil at the rate 1% w/w. All antagonists showed reduction in combination with A. javanica leaves powder at the rate1% but T. harzianum and P. aeruginosa in combination with A. javanica leaves showed promising results in complete reduction of R. solani and M. phaseolina on both crops. All growth parameters were maximum when soil was amended with A. javanica leaves powder at the rate 1% w/w and seeds were coated with T. harzianum and P. aeruginosa. (author)

  15. Dealing With A Controllable Risk Factor Like Diet In The ...

    African Journals Online (AJOL)

    Cardiovascular disease (CVD) is a silent killer in Nigeria and many parts of the world. Certain factors increase the risk of CVD. While there are controllable factors that contribute and predispose to the development of CVD like diet, exercise, tobacco use, high blood pressure and obesity, there are uncontrollable factors like ...

  16. Geomicrobiology of sublacustrine thermal vents in Yellowstone Lake: Geochemical controls on microbial community structure and function

    Directory of Open Access Journals (Sweden)

    William P. Inskeep

    2015-10-01

    Full Text Available Yellowstone Lake (Yellowstone National Park, WY, USA is a large high-altitude (2200 m, fresh-water lake, which straddles an extensive caldera and is the center of significant geothermal activity. The primary goal of this interdisciplinary study was to evaluate the microbial populations inhabiting thermal vent communities in Yellowstone Lake (Yellowstone Lake using 16S rRNA gene and random metagenome sequencing, and to determine how geochemical attributes of vent waters influence the distribution of specific microorganisms and their metabolic potential. Thermal vent waters and associated microbial biomass were sampled during two field seasons (2007 - 2008 using a remotely operated vehicle (ROV. Sublacustrine thermal vent waters (circa 50 - 90 oC contained elevated concentrations of numerous constituents associated with geothermal activity including dissolved hydrogen, sulfide, methane and carbon dioxide. Microorganisms associated with sulfur-rich filamentous ‘streamer’ communities of Inflated Plain and West Thumb (pH range 5 - 6 were dominated by bacteria from the Aquificales, but also contained thermophilic archaea from the Crenarchaeota and Euryarchaeota. Novel groups of methanogens and members of the Korarchaeota were observed in vents from West Thumb and Elliot’s Crater (pH 5 - 6. Conversely, metagenome sequence from Mary Bay vent sediments did not yield large assemblies, and contained diverse thermophilic and nonthermophilic bacterial relatives. Analysis of functional genes associated with the major vent populations indicated a direct linkage to high concentrations of carbon dioxide, reduced sulfur (sulfide and/or elemental S, hydrogen and methane in the deep thermal ecosystems. Our observations show that sublacustrine thermal vents in Yellowstone Lake support novel thermophilic communities, which contain microorganisms with functional attributes not found to date in terrestrial geothermal systems of YNP.

  17. Microbial properties of soil aggregates created by earthworms and other factors: spherical and prismatic soil aggregates from unreclaimed post-mining sites

    Czech Academy of Sciences Publication Activity Database

    Frouz, J.; Krištůfek, Václav; Livečková, M.; van Loo, D.; Jacobs, P.; van Hoorebeke, L.

    2011-01-01

    Roč. 56, č. 1 (2011), s. 36-43 ISSN 0015-5632 R&D Projects: GA MŠk LC06066; GA MŠk 2B08023; GA AV ČR 1QS600660505 Institutional research plan: CEZ:AV0Z60660521 Keywords : microbial properties * earthworms * spherical and prismatic soil aggregates Subject RIV: EH - Ecology, Behaviour Impact factor: 0.677, year: 2011

  18. Risk factors for caries - control and prevention

    Directory of Open Access Journals (Sweden)

    Melida Hasanagić

    2008-08-01

    Full Text Available Objectives. To investigate a prevalence of caries, filled permanentand extracted permanent teeth, as well as caries risk factors inschool children aged 7, 9 and 11.Methods. The survey included 800 children (296 children aged7; 254 children aged 9 and 250 children aged 11 from the MostarMunicipality, 400 of them living in both rural and urban areas.A dental mirror and standard light of dental chair were used forexamination. The DMF index (Dental Caries, Missing Teeth andFilled Teeth was determined, as well as failure in keeping teethhygiene, sugar intake with food, and incidence of oral cavity infection.Results. The dental state of permanent teeth in children aged 7and 9 has shown significant difference between the children fromrural and urban areas (p < 0,001. Out of 2,698 and 2,790 permanentteeth in children aged 11 from rural and urban areas, 1,086(40,25 % and 884 (31.68 % had caries, respectively (p < 0.01.The difference between these groups of children has been foundin relation to the index of oral hygiene too (p < 0.05.Conclusion. An identification of risk groups for getting caries wasvery important and could help health and social structures to maintaintheir programs in order to improve oral health.

  19. Chemical factors that control lignin polymerization.

    Science.gov (United States)

    Sangha, Amandeep K; Davison, Brian H; Standaert, Robert F; Davis, Mark F; Smith, Jeremy C; Parks, Jerry M

    2014-01-09

    Lignin is a complex, branched polymer that reinforces plant tissue. Understanding the factors that govern lignin structure is of central importance to the development of technologies for converting lignocellulosic biomass into fuels because lignin imparts resistance to chemical, enzymatic, and mechanical deconstruction. Lignin is formed by enzymatic oxidation of phenolic monomers (monolignols) of three main types, guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H) subunits. It is known that increasing the relative abundance of H subunits results in lower molecular weight lignin polymers and hence more easily deconstructed biomass, but it is not known why. Here, we report an analysis of frontier molecular orbitals in mono-, di-, and trilignols, calculated using density functional theory, which points to a requirement of strong p-electron density on the reacting phenolic oxygen atom of the neutral precursor for enzymatic oxidation to occur. This model is consistent with a proton-coupled electron transfer (PCET) mechanism and for the first time explains why H subunits in certain linkages (β-β or β-5) react poorly and tend to "cap" the polymer. In general, β-5 linkages with either a G or H terminus are predicted to inhibit elongation. More broadly, the model correctly accounts for the reactivity of the phenolic groups in a diverse set of dilignols comprising H and G subunits. Thus, we provide a coherent framework for understanding the propensity toward growth or termination of different terminal subunits in lignin.

  20. The microbial temperature sensitivity to warming is controlled by thermal adaptation and is independent of C-quality across a pan-continental survey

    Science.gov (United States)

    Berglund, Eva; Rousk, Johannes

    2017-04-01

    Climate models predict that warming will result in an increased loss of soil organic matter (SOM). However, field experiments suggest that although warming results in an immediate increase in SOM turnover, the effect diminishes over time. Although the use and subsequent turnover of SOM is dominated by the soil microbial community, the underlying physiology underpinning warming responses are not considered in current climate models. It has been suggested that a reduction in the perceived quality of SOM to the microbial community, and changes in the microbial thermal adaptation, could be important feed-backs to soil warming. Thus, studies distinguishing between temperature relationships and how substrate quality influences microbial decomposition are a priority. We examined microbial communities and temperature sensitivities along a natural climate gradient including 56 independent samples from across Europe. The gradient included mean annual temperatures (MAT) from ca -4 to 18 ˚ C, along with wide spans of environmental factors known to influence microbial communities, such as pH (4.0 to 8.8), nutrients (C/N from 7 to 50), SOM (from 4 to 94%), and plant communities, etc. The extensive ranges of environmental conditions resulted in wide ranges of substrate quality, indexed as microbial respiration per unit SOM, from 5-150 μg CO2g-1 SOM g-1 h-1. We hypothesised microbial communities to (1) be adapted to the temperature of their climate, leading to warm adapted bacterial communities that were more temperature sensitive (higher Q10s) at higher MAT; (2) have temperature sensitivities affected by the quality of SOM, with higher Q10s for lower quality SOM. To determine the microbial use of SOM and its dependence on temperature, we characterized microbial temperature dependences of bacterial growth (leu inc), fungal growth (ac-in-erg) and soil respiration in all 56 sites. Temperature dependences were determined using brief (ca. 1-2 h at 25˚ C) laboratory incubation

  1. Underlying Factors for Practicality of the Production Control Systems

    DEFF Research Database (Denmark)

    Arica, Emrah; Strandhagen, Jan Ola; Hvolby, Hans-Henrik

    2012-01-01

    and communication technology, coordination and feedback, human factors and decision making, and measurement are the identified factors to be taken into account. Industrial interviews with three case companies, that are participating to the research program called The Norwegian Manufacturing Future (SFI NORMAN......This paper gives indications to important factors that must be considered for effectiveness of the production control systems under uncertainty. Five key factors have been identified by the literature study. Production schedule generation and execution approach under uncertainty, information...

  2. Simulation of Feedforward-Feedback Control of Dissolved Oxygen of Microbial Repeated Fed-batch Culture

    Directory of Open Access Journals (Sweden)

    Ling Gao

    2016-09-01

    Full Text Available Fed-batch culture is often used in industry, and dissolved oxygen (DO concentration control is important in fermentation process control. DO control is often applied by using feedback (FB control strategy. But, feedforward-feedback (FF-FB control has the advantage in dealing with the time-varying characteristics resulted from the cell growth during the fermentation process. Mathematical modeling and computer simulation is a useful tool in analysis of the control system.  In this research, the FF-FB DO control and FB substrate control of repeated fed-batch culture process is modeled and simulated. The results showed the feasibility of the control strategy. These results are useful for control system development and process analyses and optimization.

  3. DEVELOPMENT OF AN ENVIRONMENTALLY BENIGN MICROBIAL INHIBITOR TO CONTROL INTERNAL PIPELINE CORROSION

    Energy Technology Data Exchange (ETDEWEB)

    J. Robert Paterek; Gemma Husmillo

    2002-07-01

    The overall program objective is to develop and evaluate environmental benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is one or more environmental benign, a.k.a. ''green'' products that can be applied to maintain the structure and dependability of the natural gas infrastructure. Capsicum sp. extracts and pure compounds were screened for their antimicrobial activity against MIC causing bacteria. Studies on the ability of these compounds to dissociate biofilm from the substratum were conducted using microtiter plate assays. Tests using laboratory scale pipeline simulators continued. Preliminary results showed that the natural extracts possess strong antimicrobial activity being comparable to or even better than the pure compounds tested against strains of sulfate reducers. Their minimum inhibitory concentrations had been determined. It was also found that they possess bactericidal properties at minimal concentrations. Biofilm dissociation activity as assessed by microtiter plate assays demonstrated varying degrees of differences between the treated and untreated group with the superior performance of the extracts over pure compounds. Such is an indication of the possible benefits that could be obtained from these natural products. Confirmatory experiments are underway.

  4. Improved performance of single-chamber microbial fuel cells through control of membrane deformation.

    Science.gov (United States)

    Zhang, Xiaoyuan; Cheng, Shaoan; Huang, Xia; Logan, Bruce E

    2010-03-15

    Cation (CEMs) and anion exchange membrane (AEMs) are commonly used in microbial fuel cells (MFCs) to enhance Coulombic efficiencies (CEs) by reducing the flux of oxygen through the cathode to bacteria on the anode. AEMs typically work better than CEMs, but in initial experiments we observed the opposite using a membrane electrode assembly MFC. The reason was identified to be membrane deformation, which resulted in water and gas trapped between the membrane and cathode. To correct this, stainless steel mesh was used to press the membrane flat against the cathode. With the steel mesh, AEM performance increased to 46+/-4 W/m(3) in a single cathode MFC, and 98+/-14 W/m(3) in a double-cathode MFC. These power densities were higher than those using a CEM of 32+/-2 W/m(3) (single cathode) and 63+/-6 W/m(3) (double cathode). Higher pH gradients across the membrane and salt precipitation on the cathode were responsible for the reduced performance of the CEM compared to the AEM. CEs reached over 90% for both membranes at >2A/m(2). These results demonstrate the importance of avoiding water accumulation in thin films between membranes and electrodes, and explain additional reasons for poorer performance of CEMs compared to AEMs. (c) 2009 Elsevier B.V. All rights reserved.

  5. Improved performance of single-chamber microbial fuel cells through control of membrane deformation

    KAUST Repository

    Zhang, Xiaoyuan

    2010-03-01

    Cation (CEMs) and anion exchange membrane (AEMs) are commonly used in microbial fuel cells (MFCs) to enhance Coulombic efficiencies (CEs) by reducing thefluxof oxygen through the cathode to bacteriaonthe anode. AEMs typically work better than CEMs, but in initial experiments we observed the opposite using a membrane electrode assembly MFC. The reason was identified to be membrane deformation, which resulted in water and gas trapped between the membrane and cathode. To correct this, stainless steel mesh was used to press the membrane flat against the cathode. With the steel mesh, AEM performance increased to 46±4W/m3 in a single cathode MFC, and 98±14W/m3 in a double-cathode MFC. These power densities were higher than those using a CEM of 32±2W/m3 (single cathode) and 63±6W/m3 (double cathode). Higher pH gradients across the membrane and salt precipitation on the cathode were responsible for the reduced performance of the CEM compared to the AEM. CEs reached over 90% for both membranes at >2A/m2. These results demonstrate the importance of avoiding water accumulation in thin films between membranes and electrodes, and explain additional reasons for poorer performance of CEMs compared to AEMs. © 2009 Elsevier B.V.

  6. Winter forest soil respiration controlled by climate and microbial community composition.

    Science.gov (United States)

    Monson, Russell K; Lipson, David L; Burns, Sean P; Turnipseed, Andrew A; Delany, Anthony C; Williams, Mark W; Schmidt, Steven K

    2006-02-09

    Most terrestrial carbon sequestration at mid-latitudes in the Northern Hemisphere occurs in seasonal, montane forest ecosystems. Winter respiratory carbon dioxide losses from these ecosystems are high, and over half of the carbon assimilated by photosynthesis in the summer can be lost the following winter. The amount of winter carbon dioxide loss is potentially susceptible to changes in the depth of the snowpack; a shallower snowpack has less insulation potential, causing colder soil temperatures and potentially lower soil respiration rates. Recent climate analyses have shown widespread declines in the winter snowpack of mountain ecosystems in the western USA and Europe that are coupled to positive temperature anomalies. Here we study the effect of changes in snow cover on soil carbon cycling within the context of natural climate variation. We use a six-year record of net ecosystem carbon dioxide exchange in a subalpine forest to show that years with a reduced winter snowpack are accompanied by significantly lower rates of soil respiration. Furthermore, we show that the cause of the high sensitivity of soil respiration rate to changes in snow depth is a unique soil microbial community that exhibits exponential growth and high rates of substrate utilization at the cold temperatures that exist beneath the snow. Our observations suggest that a warmer climate may change soil carbon sequestration rates in forest ecosystems owing to changes in the depth of the insulating snow cover.

  7. Risk factors associated with lipomyelomeningocele: a case-control study.

    Science.gov (United States)

    Esmaeili, Arash; Hanaei, Sara; Fadakar, Kaveh; Dadkhah, Sahar; Arjipour, Mahdi; Habibi, Zohreh; Nejat, Farideh; El Khashab, Mostafa

    2013-01-01

    In general, it seems that both genetic and environmental factors play important roles in the induction of neural tube defects. Lipomyelomeningocele (LipoMMC) is a rather common type of closed neural tube defect, but only limited studies have investigated the potential risk factors of this anomaly. Therefore, the purpose of this case-control study was to investigate the risk factors involved in LipoMMC formation. Various risk factors were evaluated in 35 children between 1 month and 10 years of age with LipoMMC in a hospital-based case-control study. The 2 control arms consisted of 35 children with myelomeningocele (MMC group) and 35 children with congenital anomalies other than central nervous system problems (control group). All groups were matched for age and visited the same hospital. A structured questionnaire was used for the collection of all data, including the mothers' weight and height during pregnancy, education, reproductive history, previous abortions, and socioeconomic status, as well as the parents' consanguinity and family history of the same anomalies. Univariate analysis of the children with LipoMMC compared to the control group showed that the use of periconceptional folic acid supplementation was significantly lower in the MMC and LipoMMC groups compared to the control group. In addition, comparison of the MMC and control groups revealed statistically significant differences regarding the use of folic acid and maternal obesity. In multivariate analysis, use of folic acid in the periconceptional period and during the first trimester was an independent risk factor for LipoMMC and MMC. Furthermore, maternal obesity was a significantly positive risk factor for MMC. The probable risk factors for LipoMMC were investigated in this case-control study. Consumption of folic acid in the periconceptional period and during the first trimester is an independent protective factor against LipoMMC. It seems that larger studies are needed to examine other possible

  8. Impacts of environmental factors on the whole microbial communities in the rhizosphere of a metal-tolerant plant: Elsholtzia haichowensis Sun.

    Science.gov (United States)

    Deng, Songqiang; Ke, Tan; Li, Longtai; Cai, Shenwen; Zhou, Yuyue; Liu, Yue; Guo, Limin; Chen, Lanzhou; Zhang, Dayi

    2018-06-01

    Rhizospheric microbes play important roles in plant growth and heavy metals (HMs) transformation, possessing great potential for the successful phytoremediation of environmental pollutants. In the present study, the rhizosphere of Elsholtzia haichowensis Sun was comprehensively studied to uncover the influence of environmental factors (EFs) on the whole microbial communities including bacteria, fungi and archaea, via quantitative polymerase chain reaction (qPCR) and high-throughput sequencing. By analyzing molecular ecological network and multivariate regression trees (MRT), we evaluated the distinct impacts of 37 EFs on soil microbial community. Of them, soil pH, HMs, soil texture and nitrogen were identified as the most influencing factors, and their roles varied across different domains. Soil pH was the main environmental variable on archaeal and bacterial community but not fungi, explaining 25.7%, 46.5% and 40.7% variation of bacterial taxonomic composition, archaeal taxonomic composition and a-diversity, respectively. HMs showed important roles in driving the whole microbial community and explained the major variation in different domains. Nitrogen (NH 4 -N, NO 3 -N, NO 2 -N and TN) explained 47.3% variation of microbial population composition and 15.9% of archaeal taxonomic composition, demonstrating its influence in structuring the rhizospheric microbiome, particularly archaeal and bacterial community. Soil texture accounted for 10.2% variation of population composition, 28.9% of fungal taxonomic composition, 19.2% of fungal a-diversity and 7.8% of archaeal a-diversity. Rhizosphere only showed strong impacts on fungi and bacteria, accounting for 14.7% and 4.9% variation of fungal taxonomic composition and bacterial a-diversity. Spatial distance had stronger influence on bacteria and archaea than fungi, but not as significant as other EFs. For the first time, our study provides a complete insight into key influential EFs on rhizospheric microbes and how

  9. Factors influencing warfarin control in Australia and Singapore.

    Science.gov (United States)

    Bernaitis, Nijole; Ching, Chi Keong; Teo, Siew Chong; Chen, Liping; Badrick, Tony; Davey, Andrew K; Crilly, Julia; Anoopkumar-Dukie, Shailendra

    2017-09-01

    Warfarin is widely used for patients with non-valvular atrial fibrillation (NVAF). Variations in warfarin control, as measured by time in therapeutic range (TTR), have been reported across different regions and ethnicities, particularly between Western and Asian countries. However, there is limited data on comparative factors influencing warfarin control in Caucasian and Asian patients. Therefore, the aim of this study was to determine warfarin control and potential factors influencing this in patients with NVAF in Australia and Singapore. Retrospective data was collected for patients receiving warfarin for January to June 2014 in Australia and Singapore. TTR was calculated for individuals with mean patient TTR used for analysis. Possible influential factors on TTR were analysed including age, gender, concurrent co-morbidities, and concurrent medication. The mean TTR was significantly higher in Australia (82%) than Singapore (58%). At both sites, chronic kidney disease significantly lowered this TTR. Further factors influencing control were anaemia and ageWarfarin control was significantly higher in Australia compared to Singapore, however chronic kidney disease reduced control at both sites. The different levels of control in these two countries, together with patient factors further reducing control may impact on anticoagulant choice in these countries with better outcomes from warfarin in Australia compared to Singapore. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Performance ratings and personality factors in radar controllers.

    Science.gov (United States)

    1970-09-01

    The purpose of the study was to determine whether primary or second-order personality questionnaire factors were related to job performance ratings on the Employee Appraisal Record in a sample of 264 radar controllers. A Pearson correlation matrix wa...

  11. Factors Influencing Prevention and Control of Malaria among ...

    African Journals Online (AJOL)

    AJRH Managing Editor

    investigate factors that influence malaria prevention and control practices among pregnant ... treatment of clinical cases and the promotion of ... influence their decision regarding malaria ..... have the ability to purchase anti-malaria drugs that.

  12. Simultaneous influence of indigenous microorganism along with abiotic factors controlling arsenic mobilization in Brahmaputra floodplain, India

    Science.gov (United States)

    Sathe, Sandip S.; Mahanta, Chandan; Mishra, Pushpanjali

    2018-06-01

    In the dynamic cycling of oxic and anoxic aqueous alluvial aquifer environments, varying Arsenic (As) concentrations are controlled by both abiotic and biotic factors. Studies have shown a significant form of toxic As (III) being released through the reductive dissolution of iron-oxy/hydroxide minerals and microbial reduction mechanisms, which leads to a serious health concern. The present study was performed in order to assess the abiotic and biotic factors influencing As release into the alluvial aquifer groundwater in Brahmaputra floodplain, India. The groundwater chemistry, characterization of the sediments, isolation, identification and characterization of prominent As releasing indigenous bacterium were conducted. The measured solid and liquid phases of total As concentration were ranged between 0.02 and 17.2 mg kg-1 and 8 to 353 μg L-1, respectively. The morphology and mineralogy showed the presence of detrital and authigenic mineral assemblages whereas primary and secondary As bearing Realgar and Claudetite minerals were identified, respectively. Furthermore, significant non-labile As fraction was found associated with the amorphous oxides of Fe, Mn and Al. The observed groundwater chemistry and sediment color, deduced a sub-oxic reducing aquifer conditions in As-contaminated regions. In addition, 16S rDNA sequencing results of the isolated bacterium showed the prominent Pseudomonas aeruginosa responsible for the mobilization of As, reducing condition, biomineralization and causing grey color to the sediments at the shallower and deeper aquifers in the study area. These findings suggest that microbial metabolic activities are equally responsible in iron-oxy/hydroxide reductive dissolution, controlling As mobilization in dynamic fluvial flood plains.

  13. Revisiting factors controlling methane emissions from high-Arctic tundra

    DEFF Research Database (Denmark)

    Mastepanov, M.; Sigsgaard, C.; Tagesson, T.

    2013-01-01

    controlling methane emission, i.e. temperature and water table position. Late in the growing season CH4 emissions were found to be very similar between the study years (except the extremely dry 2010) despite large differences in climatic factors (temperature and water table). Late-season bursts of CH4...... short-term control factors (temperature and water table). Our findings suggest the importance of multiyear studies with a continued focus on shoulder seasons in Arctic ecosystems....

  14. Human factors methods for nuclear control room design. Volume 2. Human factors survey of control room design practices

    International Nuclear Information System (INIS)

    Seminara, J.L.; Parsons, S.O.

    1979-11-01

    An earlier review of the control rooms of operating nuclear power plants identified many design problems having potential for degrading operator performance. As a result, the formal application of human factors principles was found to be needed. This report demonstrates the use of human factors in the design of power plant control rooms. The approaches shown in the report can be applied to operating power plants, as well as to those in the design stage. This study documents human factors techniques required to provide a sustained concern for the man-machine interface from control room concept definition to system implementation

  15. PMBLDC motor drive with power factor correction controller

    DEFF Research Database (Denmark)

    George, G.J.; Ramachandran, Rakesh; Arun, N.

    2012-01-01

    reliability, and low maintenance requirements. The proposed Power Factor Controller topology improves power quality by improving performance of PMBLDCM drive, such as reduction of AC main current harmonics, near unity power factor. PFC converter forces the drive to draw sinusoidal supply current in phase...

  16. Simplifying the audit of risk factor recording and control

    DEFF Research Database (Denmark)

    Zhao, Min; Cooney, Marie Therese; Klipstein-Grobusch, Kerstin

    2016-01-01

    BACKGROUND: To simplify the assessment of the recording and control of coronary heart disease risk factors in different countries and regions. DESIGN: The SUrvey of Risk Factors (SURF) is an international clinical audit. METHODS: Data on consecutive patients with established coronary heart disease...

  17. Effect of biotic and abiotic factors on soil microbial community diversity during primary succession on colliery spoil heaps

    Czech Academy of Sciences Publication Activity Database

    Elhottová, Dana; Frouz, Jan; Chroňáková, Alica; Malý, S.; Krištůfek, Václav; Kalčík, Jiří; Szili-Kovács, T.; Picek, T.

    2004-01-01

    Roč. 45, - (2004), s. 51 ISSN 0009-0646. [Kongres československé společnosti mikrobiologické /23./. 06.09.2004-09.09.2004, Brno] Keywords : soil microbial community * primary succession * colliery spoil heaps Subject RIV: EH - Ecology, Behaviour

  18. Assessment of the Microbial Control Measures for the Temperature and Humidity Control Subsystem Condensing Heat Exchanger of the International Space Station

    Science.gov (United States)

    Roman, Monsi C.; Steele, John W.; Marsh, Robert W.; Callahan, David M.; VonJouanne, Roger G.

    1999-01-01

    In August 1997 NASA/ Marshall Space Flight Center (MSFC) began a test with the objective of monitoring the growth of microorganisms on material simulating the surface of the International Space Station (ISS) Temperature and Humidity Control (THC) Condensing Heat Exchanger (CHX). The test addressed the concerns of potential uncontrolled microbial growth on the surface of the THC CHX subsystem. For this study, humidity condensate from a closed manned environment was used as a direct challenge to the surfaces of six cascades in a test set-up. The condensate was collected using a Shuttle-type CHX within the MSFC End-Use Equipment Testing Facility. Panels in four of the six cascades tested were coated with the ISS CHX silver impregnated hydrophilic coating. The remainder two cascade panels were coated with the hydrophilic coating without the antimicrobial component, silver. Results of the fourteen-month study are discussed in this paper. The effects on the microbial population when drying vs. not-drying the simulated THC CHX surface are also discussed.

  19. COMPLIANCE AS FACTORING BUSINESS RISK MANAGEMENT: CONTROL ASPECTS

    Directory of Open Access Journals (Sweden)

    V.K. Makarovych

    2016-03-01

    Full Text Available Indetermination of modern economy conditions and the lack of theoretical knowledge gained by domestic scientists about risk in factoring business actualize the research concerning the methodology and technique of factoring companies’ risk management. The article examines compliance which is the technology innovative for Ukrainian market of factoring risk management technologies. It is determined that the compliance is the risk management process directed to free will correspondence to state, international legislation as well as to the ethics standards accepted in the field of regulated legal relations and to the traditions of business circulation to sustain the necessary regulations and standards of market behaviour, and to consolidate the image of a factoring company. Compliance risks should be understood as the risks of missed profit or losses caused by the conflicts of interests and the discrepancy of employees’ actions to internal and external standard documents. The attention is paid to the control over the compliance. The author singles out 3 kinds of the compliance control such as institutional, operational and the compliance control over the observance of conducting business professional ethics regulations which are necessary for providing of efficient management of factoring business risks. The paper shows the organizing process of factoring business compliance control (by the development of internal standard documents, a compliance program, the foundation of compliance control subdivision, monitoring of the risks cause the choice, made by management entities of a factoring company, of the management methods of risks for their business. The development of new and improvement of existed forms of compliance control organizing process help satisfy users’ information needs and requests of the risk management factoring company department. The suggestions proposed create the grounds for the transformation and improvement of factoring

  20. CONTROL OF MICROBIAL CONTAMINANTS AND DISINFECTION BY-PRODUCTS (DBPS): COST AND PERFORMANCE

    Science.gov (United States)

    The USEPA is in the process of developing a sophisticated regulatory strategy in an attempt to balance the complex trade-offs in risks associated with controlling disinfectants and disinfection by-products (D/DBPs) in drinking water. EPA first attempted to control DBPs in 1974, w...

  1. Evaluation of factors affecting adherence to asthma controller ...

    African Journals Online (AJOL)

    Evaluation of factors affecting adherence to asthma controller therapy in chest clinics in a sub-Saharan African setting: a cross-sectional study. ... Background: Adherence to controller therapy in asthma is a major concern during the management of the disease. Objective: To determine the adherence rate and identify the ...

  2. Vertical structure and pH as factors for chitinolytic and pectinolytic microbial community of soils and terrestrial ecosystems of different climatic zones

    Science.gov (United States)

    Lukacheva, Evgeniya; Natalia, Manucharova

    2016-04-01

    technique developed that is used to detect and localize the presence or absence of specific DNA sequences on chromosomes. pH as one of the factors which can have influence on degradation of biopolymers was studied for chitiolytic communities of different zones. And results were compared with direct studyings by method of "sowing" on a Petri dishes. Thus, we compared old classical methods with modern molecular studies. The difference between climatic zones was studied and the mathematical model was created. The mathematic model could be use in different aims, such as prognosis of microbial community composition and their classification.

  3. Human factors survey of advanced instrumentation and controls

    International Nuclear Information System (INIS)

    Carter, R.J.

    1989-01-01

    A survey oriented towards identifying the human factors issues in regard to the use of advanced instrumentation and controls (I ampersand C) in the nuclear industry was conducted. A number of United States (US) and Canadian nuclear vendors and utilities were participants in the survey. Human factors items, subsumed under the categories of computer-generated displays (CGD), controls, organizational support, training, and related topics, were discussed. The survey found the industry to be concerned about the human factors issues related to the implementation of advanced I ampersand C. Fifteen potential human factors problems were identified. They include: the need for an advanced I ampersand C guideline equivalent to NUREG-0700; a role change in the control room from operator to supervisor; information overload; adequacy of existing training technology for advanced I ampersand C; and operator acceptance and trust. 11 refs., 1 tab

  4. Human factors evaluation of the engineering test reactor control room

    International Nuclear Information System (INIS)

    Banks, W.W.; Boone, M.P.

    1981-03-01

    The Reactor and Process Control Rooms at the Engineering Test Reactor were evaluated by a team of human factors engineers using available human factors design criteria. During the evaluation, ETR, equipment and facilities were compared with MIL-STD-1472-B, Human Engineering design Criteria for Military Systems. The focus of recommendations centered on: (a) displays and controls; placing displays and controls in functional groups; (b) establishing a consistent color coding (in compliance with a standard if possible); (c) systematizing annunciator alarms and reducing their number; (d) organizing equipment in functional groups; and (e) modifying labeling and lines of demarcation

  5. Dietary pattern and lifestyle factors in asthma control

    Directory of Open Access Journals (Sweden)

    Mohammed Noufal Poongadan

    2016-01-01

    Full Text Available Background: The prevalence of asthma in adults varied from 0.96% to 11.03% while in children ranged from 2.3% to 11.9% in India. A number of factors including genetic predisposition, environment, and lifestyle factors including dietary habits influence the development and expression of asthma. The goal of asthma treatment is to achieve and maintain clinical control, which can be achieved in a majority of patients with pharmacologic intervention strategy. Objective: To assess the role of diet and lifestyle factors in asthma control in Indian population. Materials and Methods: Diagnosed asthma patients (aged 12-40 years were enrolled from the outpatient clinics. All patients were followed up and reassessed after 4 weeks with asthma control test (ACT and dietary and lifestyle questionnaire. The assessment of dietary pattern was performed by food frequency questionnaire (Nordic Nutrition Recommendations-Danish Physical Activity Questionnaire. The lifestyle factor included body mass index, smoking status, tobacco chewing, alcohol consumption, duration of travel (h/week, mental stress (visual analog scale: 0-10, sports activity - h/day, television (TV watching/video games - h/day, duration of sleep - h/day. Results: Seventy-five asthma patients (43 males and 32 females were divided into three groups according to ACT, 18 (24% patients in poorly-controlled asthma, 35 (46.7% in well-controlled asthma, and 22 (29.3% patients with totally-controlled asthma. Increased consumption of vegetables and cereals in patients with total-controlled asthma while increased consumption of sugar, nonvegetarian, fast food, salted and fried snacks in patients with poorly-controlled asthma. Poorly-controlled asthma had the highest duration of watching TV and sleep and least duration of travel and sports, though the results failed to reach statistical significance. Conclusion: The dietary and lifestyle factors too contribute to degree of control of asthma in India.

  6. Taking account of human factors in control-room design

    International Nuclear Information System (INIS)

    Dien, Y.; Montmayeul, R.

    1995-07-01

    Since the Three Mile Island accident two ways for improving the Human-Machine Interface have mainly been followed: the development of computerized operator aids in existing control-rooms and the design of advanced control-rooms. Insufficient attention paid to human factors in the design of operator aids has generally led to these aids being neglected or unused by their potential users. While for the design of advanced control-rooms efforts have been made for dealing with human factors in more extensive way. Based upon this experience, a general method for taking account of human factors in a control-room design has been devised and is described in this paper. (author)

  7. Microbial contamination of stored hydrocarbon fuels and its control Contaminação microbiana de combustíveis hidrocarbonados e o seu controle

    Directory of Open Access Journals (Sweden)

    Christine C. Gaylarde

    1999-01-01

    Full Text Available The major microbial problem in the petroleum refining industry is contamination of stored products, which can lead to loss of product quality, formation of sludge and deterioration of pipework and storage tanks, both in the refinery and at the end-user. Three major classes of fuel are discussed in this article - gasoline, aviation kerosene and diesel, corresponding to increasingly heavy petroleum fractions. The fuel that presents the most serious microbiological problems is diesel. The many microorganisms that have been isolated from hydrocarbon fuel systems are listed. The conditions required for microbial growth and the methods used to monitor and to control this activity are discussed. The effects of various fuel additives, including biocides, are considered.O problema microbiano maior na indústria de refino de petróleo é a contaminação de produtos armazenados, que pode levar à perda da qualidade, à formação de borra e à deterioração de tubulações e tanques de estocagem, na refinaria e no usuário. São abordadas, neste artigo, três classes de combustível, gasolina, querosene de aviação e óleo diesel, correspondente à ordem crescente de peso no fracionamento de petróleo. O óleo diesel apresenta os problemas microbiológicos mais sérios. São relatados os diversos microrganismos isolados de sistemas de combustíveis hidrocarbonados. São apresentadas as condições necessárias para crescimento microbiano e os métodos utilizados para o monitoramento e controle desse crescimento. Os efeitos de diversos aditivos, inclusive biocidas, são discutidos

  8. Degradation of 1,1,2,2-tetrachloroethane and accumulation of vinyl chloride in wetland sediment microcosms and in situ porewater: biogeochemical controls and associations with microbial communities

    Science.gov (United States)

    Lorah, Michelle M.; Voytek, Mary A.

    2004-05-01

    The biodegradation pathways of 1,1,2,2-tetrachloroethane (TeCA) and 1,1,2-trichloroethane (112TCA) and the associated microbial communities in anaerobic wetland sediments were evaluated using concurrent geochemical and genetic analyses over time in laboratory microcosm experiments. Experimental results were compared to in situ porewater data in the wetland to better understand the factors controlling daughter product distributions in a chlorinated solvent plume discharging to a freshwater tidal wetland at Aberdeen Proving Ground, Maryland. Microcosms constructed with wetland sediment from two sites showed little difference in the initial degradation steps of TeCA, which included simultaneous hydrogenolysis to 112TCA and dichloroelimination to 1,2-dichloroethene (12DCE). The microcosms from the two sites showed a substantial difference, however, in the relative dominance of subsequent dichloroelimination of 112TCA. A greater dominance of 112TCA dichloroelimination in microcosms constructed with sediment that was initially iron-reducing and subsequently simultaneously iron-reducing and methanogenic caused approximately twice as much vinyl chloride (VC) production as microcosms constructed with sediment that was methanogenic only throughout the incubation. The microcosms with higher VC production also showed substantially more rapid VC degradation. Field measurements of redox-sensitive constituents, TeCA, and its anaerobic degradation products along flowpaths in the wetland porewater also showed greater production and degradation of VC with concurrent methanogenesis and iron reduction. Molecular fingerprinting indicated that bacterial species [represented by a peak at a fragment size of 198 base pairs (bp) by MnlI digest] are associated with VC production from 112TCA dichloroelimination, whereas methanogens (190 and 307 bp) from the Methanococcales or Methanobacteriales family are associated with VC production from 12DCE hydrogenolysis. Acetate-utilizing methanogens

  9. Vulnerability of Permafrost Soil Carbon to Climate Warming: Evaluating Controls on Microbial Community Composition

    Science.gov (United States)

    Abstract: Despite the fact that permafrost soils contain up to half of the carbon (C) in terrestrial pools, we have a poor understanding of the controls on decomposition in thawed permafrost. Global climate models assume that decomposition increases linearly with temperature, yet decomposition in th...

  10. Apple Replant Disease: Role of microbial ecology in cause and control

    Science.gov (United States)

    1. Apple replant disease (ARD) has been reported from all major fruit-growing regions of the world, and is often caused by a consortium of biological agents. Development of non-fumigant alternatives for the control of this disease has been hindered by the absence of consensus concerning the etiology...

  11. Controlling herbicide-susceptible, -tolerant and -resistant weeds with microbial bioherbicides

    Science.gov (United States)

    The management of weeds is a necessary but expensive challenge. Public concerns of health, safety, and sustainability have increased interest in reducing the use of synthetic chemicals for weed control. Alternatives to chemical herbicides, such as bioherbicides, may offer an alternative to herbicide...

  12. Microbial- and isothiocyanate-mediated control of Phytophthora and Pythium species

    Science.gov (United States)

    M.F. Cohen; E. Yamamoto; E. Condeso; B.L. Anacker; N. Rank; M. Mazzola

    2008-01-01

    Plant pathogens of the oomycete lineage share common susceptibilities to many biotic and abiotic stresses. We are investigating the potential of antagonistic bacteria, isothiocyanates, and mycophagous amoebae to control diseases caused by Phytophthora spp., including the etiologic agent of sudden oak death, Phytophthora ramorum (...

  13. Human Factors Engineering Aspects of Modifications in Control Room Modernization

    Energy Technology Data Exchange (ETDEWEB)

    Hugo, Jacques [Idaho National Lab. (INL), Idaho Falls, ID (United States); Clefton, Gordon [Idaho National Lab. (INL), Idaho Falls, ID (United States); Joe, Jeffrey [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2017-06-01

    This report describes the basic aspects of control room modernization projects in the U.S. nuclear industry and the need for supplementary guidance on the integration of human factors considerations into the licensing and regulatory aspects of digital upgrades. The report pays specific attention to the integration of principles described in NUREG-0711 (Human Factors Engineering Program Review Model) and how supplementary guidance can help to raise general awareness in the industry regarding the complexities of control room modernization projects created by many interdependent regulations, standards and guidelines. The report also describes how human factors engineering principles and methods provided by various resources and international standards can help in navigating through the process of licensing digital upgrades. In particular, the integration of human factors engineering guidance and requirements into the process of licensing digital upgrades can help reduce uncertainty related to development of technical bases for digital upgrades that will avoid the introduction of new failure modes.

  14. Comparing a microbial biocide and chlorine as zebra mussel control strategies in an Irish drinking water treatment plant

    Directory of Open Access Journals (Sweden)

    Sara Meehan

    2013-06-01

    Full Text Available A need exists for an environmentally friendly mussel control method to replace chlorine and other traditional control methods currentlyutilised in drinking water plants and other infested facilities. Zequanox® is a newly commercialised microbial biocide for zebra and quaggamussels comprised of killed Pseudomonas fluorescens CL145A cells. The objective of this study was to compare the efficacy of adevelopmental formulation of Zequanox (referred to as MBI 401 FDP and chlorine treatments on adult and juvenile zebra mussels byrunning a biobox trial in conjunction with chlorine treatments at an infested Irish drinking water treatment plant. Since 2009, the plantmanagement has used a residual chlorine concentration of 2 mg/L in autumn to control both adult zebra mussels and juvenile settlement intheir three concrete raw water chambers. Juvenile mussel settlement was monitored in three bioboxes as well as in three treatment chambersin the plant for three months prior to treatment. Adult mussels were seeded into the chambers and bioboxes four days before treatment. InOctober 2011, the bioboxes were treated with MBI 401 FDP at 200 mg active substance/L, while chlorine treatment took place in the waterchambers. The MBI 401 FDP treatment lasted only 8 hours while chlorine treatment lasted seven days. Juvenile numbers were reduced tozero in both the bioboxes and treated chambers within seven days. Adult mussel mortality reached 80% for both the chlorine and MBI 401FDP treatment; however, mortality was achieved faster in the chlorine treatment. These results provided important insights into zebra musselcontrol alternatives to chlorine and supported further development of the now commercial product, Zequanox.

  15. Top-down controls on bacterial community structure: microbial network analysis of bacteria, T4-like viruses and protists

    Science.gov (United States)

    Chow, Cheryl-Emiliane T; Kim, Diane Y; Sachdeva, Rohan; Caron, David A; Fuhrman, Jed A

    2014-01-01

    Characterizing ecological relationships between viruses, bacteria and protists in the ocean are critical to understanding ecosystem function, yet these relationships are infrequently investigated together. We evaluated these relationships through microbial association network analysis of samples collected approximately monthly from March 2008 to January 2011 in the surface ocean (0–5 m) at the San Pedro Ocean Time series station. Bacterial, T4-like myoviral and protistan communities were described by Automated Ribosomal Intergenic Spacer Analysis and terminal restriction fragment length polymorphism of the gene encoding the major capsid protein (g23) and 18S ribosomal DNA, respectively. Concurrent shifts in community structure suggested similar timing of responses to environmental and biological parameters. We linked T4-like myoviral, bacterial and protistan operational taxonomic units by local similarity correlations, which were then visualized as association networks. Network links (correlations) potentially represent synergistic and antagonistic relationships such as viral lysis, grazing, competition or other interactions. We found that virus–bacteria relationships were more cross-linked than protist–bacteria relationships, suggestive of increased taxonomic specificity in virus–bacteria relationships. We also found that 80% of bacterial–protist and 74% of bacterial–viral correlations were positive, with the latter suggesting that at monthly and seasonal timescales, viruses may be following their hosts more often than controlling host abundance. PMID:24196323

  16. Biological Stability of Drinking Water: Controlling Factors, Methods, and Challenges

    KAUST Repository

    Prest, Emmanuelle I.; Hammes, Frederik; van Loosdrecht, Mark C. M.; Vrouwenvelder, Johannes S.

    2016-01-01

    -depth characterization of bacterial communities in drinking water. We discussed, how knowledge gained from novel techniques will improve design and monitoring of water treatment and distribution systems in order to maintain good drinking water microbial quality up

  17. Factors controlling bacteria and protists in selected Mazurian eutrophic lakes (North-Eastern Poland) during spring

    Science.gov (United States)

    2013-01-01

    Background The bottom-up (food resources) and top-down (grazing pressure) controls, with other environmental parameters (water temperature, pH) are the main factors regulating the abundance and structure of microbial communities in aquatic ecosystems. It is still not definitively decided which of the two control mechanisms is more important. The significance of bottom-up versus top-down controls may alter with lake productivity and season. In oligo- and/or mesotrophic environments, the bottom-up control is mostly important in regulating bacterial abundances, while in eutrophic systems, the top-down control may be more significant. Results The abundance of bacteria, heterotrophic (HNF) and autotrophic (ANF) nanoflagellates and ciliates, as well as bacterial production (BP) and metabolically active cells of bacteria (CTC, NuCC, EST) were studied in eutrophic lakes (Mazurian Lake District, Poland) during spring. The studied lakes were characterized by high nanoflagellate (mean 17.36 ± 8.57 × 103 cells ml-1) and ciliate abundances (mean 59.9 ± 22.4 ind. ml-1) that were higher in the euphotic zone than in the bottom waters, with relatively low bacterial densities (4.76 ± 2.08 × 106 cells ml-1) that were lower in the euphotic zone compared to the profundal zone. Oligotrichida (Rimostrombidium spp.), Prostomatida (Urotricha spp.) and Scuticociliatida (Histiobalantium bodamicum) dominated in the euphotic zone, whereas oligotrichs Tintinnidium sp. and prostomatids Urotricha spp. were most numerous in the bottom waters. Among the staining methods used to examine bacterial cellular metabolic activity, the lowest percentage of active cells was recorded with the CTC (1.5–15.4%) and EST (2.7–14.2%) assay in contrast to the NuCC (28.8–97.3%) method. Conclusions In the euphotic zone, the bottom-up factors (TP and DOC concentrations) played a more important role than top-down control (grazing by protists) in regulating bacterial numbers and activity

  18. Transcription Factor Zbtb20 Controls Regional Specification of Mammalian Archicortex

    DEFF Research Database (Denmark)

    Rosenthal, Eva Helga

    2010-01-01

    Combinatorial expression of sets of transcription factors (TFs) along the mammalian cortex controls its subdivision into functional areas. Unlike neocortex, only few recent data suggest genetic mechanisms controlling the regionalization of the archicortex. TF Emx2 plays a crucial role in patterning...... later on becoming restricted exclusively to postmitotic neurons of hippocampus (Hi) proper, dentate gyrus (DG), and two transitory zones, subiculum (S) and retrosplenial cortex (Rsp). Analysis of Zbtb20-/- mice revealed altered cortical patterning at the border between neocortex and archicortex...

  19. Active Power Factor Correction Using a Sliding Mode Controller

    Directory of Open Access Journals (Sweden)

    Korhan KAYIŞLI

    2008-03-01

    Full Text Available In this paper, a sliding mode controller is designed for active shaping of the input current in the boost converter. Robustness of the designed controller is tested with variable output voltage references, different loads and network voltage variations. For the simulations, MATLAB/Simulink programme is used. From simulation results, the same phase was provided between input current and input voltage and nearly unity power factor was obtained.

  20. On frequency-weighted coprime factorization based controller reduction

    OpenAIRE

    Varga, Andras

    2003-01-01

    We consider the efficient solution of a class of coprime factorization based controller approximation problems by using frequency-weighted balancing related model reduction approaches. It is shown that for some special stability enforcing frequency-weights, the computation of the frequency-weighted controllability and observability grammians can be done by solving reduced order Lyapunov equations. The new approach can be used in conjunction with accuracy enhancing square-root and balancing-fr...

  1. Potential risk factors for diabetic neuropathy: a case control study

    Directory of Open Access Journals (Sweden)

    Nooraei Mahdi

    2005-12-01

    Full Text Available Abstract Background Diabetes mellitus type II afflicts at least 2 million people in Iran. Neuropathy is one of the most common complications of diabetes and lowers the patient's quality of life. Since neuropathy often leads to ulceration and amputation, we have tried to elucidate the factors that can affect its progression. Methods In this case-control study, 110 diabetic patients were selected from the Shariati Hospital diabetes clinic. Michigan Neuropathic Diabetic Scoring (MNDS was used to differentiate cases from controls. The diagnosis of neuropathy was confirmed by nerve conduction studies (nerve conduction velocity and electromyography. The multiple factors compared between the two groups included consumption of angiotensin converting enzyme inhibitors (ACEI, blood pressure, serum lipid level, sex, smoking, method of diabetes control and its quality. Results Statistically significant relationships were found between neuropathy and age, gender, quality of diabetes control and duration of disease (P values in the order: 0.04, 0.04, Conclusion In this study, hyperglycemia was the only modifiable risk factor for diabetic neuropathy. Glycemic control reduces the incidence of neuropathy, slows its progression and improves the diabetic patient's quality of life. More attention must be paid to elderly male diabetic patients with poor diabetes control with regard to regular foot examinations and more practical education.

  2. Factors controlling accumulation of soil organic carbon along vegetation succession in a typical karst region in Southwest China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Shujuan [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Wei [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); Wang, Kelin, E-mail: kelin@isa.ac.cn [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); Pan, Fujing [Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125 (China); Huanjiang Observation and Research Station of Karst Ecosystem, Chinese Academy of Sciences, Huanjiang, Guangxi Zhuang Autonomous Region 547100 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yang, Shan [Changsha university, Changsha 410003 (China); Shu, Shiyan [Changjiang Project Supervision & Consultancy Co. Ltd, Wuhan 430010 (China); Changjiang Ecology (Hubei) Technology Development LLC, Wuhan 430010 (China)

    2015-07-15

    Vegetation succession enhances the accumulation of carbon in the soil. However, little is known about the mechanisms underlying soil organic carbon (SOC) accumulation in different vegetation types in the karst region of Southwest China. The goal of this study was to identify and prioritize the effects of environmental parameters, including soil physico-chemical properties, microbial biomass, enzyme activities, and litter characteristics, on SOC accumulation along a vegetation succession sere (grassland, shrubland, secondary forest, and primary forest) in the karst landscape of Southwest China. Relationships between these parameters and SOC were evaluated by redundancy analysis. The results showed that SOC accumulation was significantly different among vegetation types (P < 0.01) and increased with vegetation succession (from 29.10 g·kg{sup −1} in grassland to 73.92 g·kg{sup −1} in primary forest). Soil biochemistry and physical characteristics significantly affected the accumulation of SOC. Soil microbial biomass showed a predominant effect on SOC in each of the four vegetation types. In addition, the soil physical property (especially the silt content) was another controlling factor in the early stages (grassland), and urease activity and saccharase activity were important controlling factors in the early-middle and middle-late stages, respectively. Litter characteristics only showed mild effects on SOC accumulation. Variation partitioning analysis showed that the contribution of sole main factors to SOC variation decreased, while the interaction effect among parameters increased along the succession gradient. - Highlights: • Vegetation restoration is conducive to soil carbon sequestration in karst areas. • The factors controlling SOC accumulation differed along vegetation succession. • The interaction effect among significant factors became more and more prominent along succession.

  3. Alternate switching between microbial fuel cell and microbial electrolysis cell operation as a new method to control H2O2 level in Bioelectro-Fenton system

    DEFF Research Database (Denmark)

    Zhang, Yifeng; Wang, Yong; Angelidaki, Irini

    2015-01-01

    cell (MEC) and microbial fuel cell (MFC) mode of operation was developed to meet the challenges. In the MEC mode, a bioelectrochemical system (BES) produces H2O2 which reacts with Fenton's reagent (Fe II) to form hydroxyradical. The unused H2O2 (residual H2O2) is removed as electron acceptor...... by switching the system to MFC mode of operation. Complete decolorization and mineralization of 50 mg L−1 methylene blue (MB) was achieved in the MEC mode with apparent first order rate constants of 0.43 and 0.22 h−1, respectively. After switching to the MFC mode, residual H2O2 of 180 mg L−1 was removed...... at a removal rate of 4.61 mg L−1 h−1 while generating a maximum current density of 0.49 A m−2. The MB degradation and residual H2O2 removal were affected by external resistance, cathode pH and initial MB concentration. Furthermore, the system performance was enhanced under stack operation. This study provides...

  4. Microbial pathogens in raw pork, chicken, and beef: benefit estimates for control using irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, T.

    1985-12-01

    Various control procedures have been suggested for reducing foodborne infectious diseases. Receiving considerable attention is irradiation. This report estimates the medical and wage (or productivity) benefits associated with prevention of five human diseases transmitted by beef, pork, and chicken. (These diseases can also be transmitted by other vectors, such as eggs, milk, and pets. But these sources are not included in the analysis.) All of these foodborne infectious diseases - salmonellosis, campylobacteriosis, trichinosis, tapeworm, and toxoplasmosis - could be significantly reduced by irradiating meat and poultry. The Food and Drug Administration (FDA) has just approved irradiation of pork to prevent trichinosis (50FR 29658-59) and is considering approval of irradiation of chicken to kill Salmonella. 22 references.

  5. Microbial pathogens in raw pork, chicken, and beef: benefit estimates for control using irradiation

    International Nuclear Information System (INIS)

    Roberts, T.

    1985-01-01

    Various control procedures have been suggested for reducing foodborne infectious diseases. Receiving considerable attention is irradiation. This report estimates the medical and wage (or productivity) benefits associated with prevention of five human diseases transmitted by beef, pork, and chicken. (These diseases can also be transmitted by other vectors, such as eggs, milk, and pets. But these sources are not included in the analysis.) All of these foodborne infectious diseases - salmonellosis, campylobacteriosis, trichinosis, tapeworm, and toxoplasmosis - could be significantly reduced by irradiating meat and poultry. The Food and Drug Administration (FDA) has just approved irradiation of pork to prevent trichinosis (50FR 29658-59) and is considering approval of irradiation of chicken to kill Salmonella. 22 references

  6. Environmental controls on photosynthetic microbial mat distribution and morphogenesis on a 3.42 Ga clastic-starved platform.

    Science.gov (United States)

    Tice, Michael M

    2009-12-01

    Three morphotypes of microbial mats are preserved in rocks deposited in shallow-water facies of the 3.42 Ga Buck Reef chert (BRC). Morphotype alpha consists of fine anastomosing and bifurcating carbonaceous laminations, which loosely drape underlying detrital grains or form silica-filled lenses. Morphotype beta consists of meshes of fine carbonaceous strands intergrown with detrital grains and dark laminations, which loosely drape coarse detrital grains. Morphotype gamma consists of fine, even carbonaceous laminations that tightly drape underlying detrital grains. Preservation of nearly uncompacted mat morphologies and detrital grains deposited during mat growth within a well-characterized sedimentary unit makes quantitative correlation between morphology and paleoenvironment possible. All mats are preserved in the shallowest-water interval of those rocks deposited below normal wave base and above storm wave base. This interval is bounded below by a transgressive lag formed during regional flooding and above by a small condensed section that marks a local relative sea-level maximum. Restriction of all mat morphotypes to the shallowest interval of the storm-active layer in the BRC ocean reinforces previous interpretations that these mats were constructed primarily by photosynthetic organisms. Morphotypes alpha and beta dominate the lower half of this interval and grew during deposition of relatively coarse detrital carbonaceous grains, while morphotype gamma dominates the upper half and grew during deposition of fine detrital carbonaceous grains. The observed mat distribution suggests that either light intensity or, more likely, small variations in ambient current energy acted as a first-order control on mat morphotype distribution. These results demonstrate significant environmental control on biological morphogenetic processes independent of influences from siliciclastic sedimentation.

  7. Perinatal mortality and associated risk factors: a case control study ...

    African Journals Online (AJOL)

    BACKGROUND: Perinatal mortality is reported to be five times higher in developing than in developed nations. Little is known about the commonly associated risk factors for perinatal mortality in Southern Nations National Regional State of Ethiopia. METHODS: A case control study for perinatal mortality was conducted in ...

  8. Factors affecting sustainable animal trypanosomosis control in parts ...

    African Journals Online (AJOL)

    This study examined the factors affecting sustainable trypanosomiasis control in parts of Kaduna State within the sub-humid savannah ecological zone of Nigeria. Focus group discussions were ... More awareness and preference for pour-on and aerial spraying were higher than the use of traps, target or screens. Rearing of ...

  9. Physiology and Endocrinology Symposium. Factors controlling puberty in beef heifers

    Science.gov (United States)

    The Physiology and Endocrinology Symposium on “Factors controlling puberty in beef heifers” was held at the joint annual meeting of the American Dairy Science Association and the American Society of Animal Science in New Orleans, Louisiana, USA, July 10 to 14, 2011. The objective of the symposium w...

  10. Risk factors for cataract: A case control study

    Directory of Open Access Journals (Sweden)

    Ughade Suresh

    1998-01-01

    Full Text Available The present study was designed as a hospital-based, group-matched, case-control investigation into the risk factors associated with age-related cataract in central India. The study included 262 cases of age-related cataract and an equal number of controls. A total of 21 risk factors were evaluated: namely, low socioeconomic status (SES, illiteracy, marital status, history of diarrhoea, history of diabetes, glaucoma, use of cholinesterase inhibitors, steroids, spironolactone, nifedipine, analgesics, myopia early in life, renal failure, heavy smoking, heavy alcohol consumption, hypertension, low body mass index (BMI, use of cheaper cooking fuel, working in direct sunlight, family history of cataract, and occupational exposure. In univariate analysis, except marital status, low BMI, renal failure, use of steroids, spironolactone, analgesics, and occupational exposure, all 14 other risk factors were found significantly associated with age-related cataract. Unconditional multiple logistic regression analysis confirmed the significance of low SES, illiteracy, history of diarrhoea, diabetes, glaucoma, myopia, smoking, hypertension and cheap cooking fuel. The etiological role of these risk factors in the outcome of cataract is confirmed by the estimates of attributable risk proportion. The estimates of population attributable risk proportion for these factors highlight the impact of elimination of these risk factors on the reduction of cataract in this population.

  11. Factors affecting the performance of a single-chamber microbial fuel cell-type biological oxygen demand sensor.

    Science.gov (United States)

    Yang, Gai-Xiu; Sun, Yong-Ming; Kong, Xiao-Ying; Zhen, Feng; Li, Ying; Li, Lian-Hua; Lei, Ting-Zhou; Yuan, Zhen-Hong; Chen, Guan-Yi

    2013-01-01

    Microbial fuel cells (MFCs) are devices that exploit microorganisms as biocatalysts to degrade organic matter or sludge present in wastewater (WW), and thereby generate electricity. We developed a simple, low-cost single-chamber microbial fuel cell (SCMFC)-type biochemical oxygen demand (BOD) sensor using carbon felt (anode) and activated sludge, and demonstrated its feasibility in the construction of a real-time BOD measurement system. Further, the effects of anodic pH and organic concentration on SCMFC performance were examined, and the correlation between BOD concentration and its response time was analyzed. Our results demonstrated that the SCMFC exhibited a stable voltage after 132 min following the addition of synthetic WW (BOD concentration: 200 mg/L). Notably, the response signal increased with an increase in BOD concentration (range: 5-200 mg/L) and was found to be directly proportional to the substrate concentration. However, at higher BOD concentrations (>120 mg/L) the response signal remained unaltered. Furthermore, we optimized the SCMFC using synthetic WW, and tested it with real WW. Upon feeding real WW, the BOD values exhibited a standard deviation from 2.08 to 8.3% when compared to the standard BOD5 method, thus demonstrating the practical applicability of the developed system to real treatment effluents.

  12. Microbial ecology of Rum Jungle, III. Leaching behaviour of sulphidic waste material under controlled conditions

    International Nuclear Information System (INIS)

    Babij, T.; Goodman, A.; Khalid, A.M.; Ralph, B.J.

    1981-12-01

    The discharge, into river systems, of acid and heavy metals generated by leaching of sulphidic waste materials at the abandoned opencut uranium mine at Rum Jungle, Northern Territory, is causing continuing pollution of the surrounding environment. The maximum effects of acid and microorganisms on samples from the overburden dump material, under defined and controlled environmental conditions, were assessed using reactor systems. These samples came from the overburden dump resulting from the mining of White's orebody. Similarly, the stability of tailings material under conditions of flooding and increasing acidity was determined. At ph 2.5, metals in White's dump material were solubilised by acid attack only, whereas at pH 3.5, bacterial activity (principally that of Thiobacillus ferrooxidans) generated acidity and contributed significantly to metal release. Under microaerophilic conditions Thiobacillus ferrooxidans continued to effect metal release from the ore, but did not produce further acidity. If White's overburden is returned to the acidic, flooded opencuts, complete solubilisation of the material will occur. The exclusion of oxygen from the dump will not necessarily stop bacterially catalysed leaching processes. Under highly aerated and agitated flooded conditions the tailings material was not active, except for copper release of about 2 g kg -1 ore at pH 4.0. The only deleterious element released by increasing acidity was copper, which was 100 per cent solubilised at pH 2.5. Uranium was always lss than 3 μg kg -1 ore, and lead was detected only at pH 2.5. Indigenous leaching bacteria did not develop

  13. A cross-sectional study examining the prevalence and risk factors for anti-microbial-resistant generic Escherichia coli in domestic dogs that frequent dog parks in three cities in south-western Ontario, Canada.

    Science.gov (United States)

    Procter, T D; Pearl, D L; Finley, R L; Leonard, E K; Janecko, N; Reid-Smith, R J; Weese, J S; Peregrine, A S; Sargeant, J M

    2014-06-01

    Anti-microbial resistance can threaten health by limiting treatment options and increasing the risk of hospitalization and severity of infection. Companion animals can shed anti-microbial-resistant bacteria that may result in the exposure of other dogs and humans to anti-microbial-resistant genes. The prevalence of anti-microbial-resistant generic Escherichia coli in the faeces of dogs that visited dog parks in south-western Ontario was examined and risk factors for shedding anti-microbial-resistant generic E. coli identified. From May to August 2009, canine faecal samples were collected at ten dog parks in three cities in south-western Ontario, Canada. Owners completed a questionnaire related to pet characteristics and management factors including recent treatment with antibiotics. Faecal samples were collected from 251 dogs, and 189 surveys were completed. Generic E. coli was isolated from 237 of the faecal samples, and up to three isolates per sample were tested for anti-microbial susceptibility. Eighty-nine percent of isolates were pan-susceptible; 82.3% of dogs shed isolates that were pan-susceptible. Multiclass resistance was detected in 7.2% of the isolates from 10.1% of the dogs. Based on multilevel multivariable logistic regression, a risk factor for the shedding of generic E. coli resistant to ampicillin was attending dog day care. Risk factors for the shedding of E. coli resistant to at least one anti-microbial included attending dog day care and being a large mixed breed dog, whereas consumption of commercial dry and home cooked diets was protective factor. In a multilevel multivariable model for the shedding of multiclass-resistant E. coli, exposure to compost and being a large mixed breed dog were risk factors, while consumption of a commercial dry diet was a sparing factor. Pet dogs are a potential reservoir of anti-microbial-resistant generic E. coli; some dog characteristics and management factors are associated with the prevalence of anti-microbial

  14. The effects of environmental physical factors on the microbial communities and the distribution of different CO2 fixation pathways in a limestone landscape

    Science.gov (United States)

    Wun, S. R.; Huang, T. Y.; Hsu, B. M.; Fan, C. W.

    2017-12-01

    We aimed to study the effects of physical factors on the relative abundance of bacteria and their preferential admissions of autotrophic CO2 fixation pathways after subjected to environmental long-term influence. The Narrow-Sky located in upper part of Takangshan is a small gulch of Pleistocene coralline limestone formation in southern Taiwan. The physical parameters such as illumination, humidity, and temperature were varied largely in habitats around the gulch, namely on the limestone wall at the opening of gulch, on the coordinate ground soil, on the wall inside the gulch, and the water drip from limestone wall. The total organic carbon was measured in solid samples to evaluate the biomass of the habitats. A metagenomic approach was carried out to reveal their microbial community structure. After the metagenomic library of operational taxonomic units (OTUs) was constructed, a BLAST search by "nomenclature of bacteria" instead of sequences between the OTU libraries and KEGG database was carried out to generate libraries of "model microbial communities", which the complete genomes of the entire bacterial populations were available. Our results showed the biomass of habitats in the opening of gulch was twice higher than the inside, suggesting the illumination played an important role in biosynthesis. In quantitative comparison in key enzymes of CO2 fixation pathways by model communities, 70% to 90% of bacteria possessed key enzymes of Fuchs-Holo cycle, while only 5% to 20% of bacteria contained key enzymes of Calvin-Benson cycle. The key enzymes for hydroxypropionate/ hydroxybutyrate and dicarboxylate/ 4-hydroxybutyrate cycles were not found in this study. In the water sample, approximate 10% of bacteria consisted of the key enzyme for Arnon-Buchanan cycle. Less than 2% of bacteria in all habitats take the reductive acetyl-CoA cycle for CO2 fixation. This study provides a novel method to study biosynthetic process of microbial communities in natural habitats.

  15. Risk factors for syphilis in women: case-control study

    Directory of Open Access Journals (Sweden)

    Vilma Costa de Macêdo

    2017-08-01

    Full Text Available ABSTRACT OBJECTIVE To determine the sociodemographic, behavioral, and health care factors related to the occurrence of syphilis in women treated at public maternity hospitals. METHODS This is a case-control study (239 cases and 322 controls with women admitted to seven maternity hospitals in the municipality of Recife, Brazil, from July 2013 to July 2014. Eligible women were recruited after the result of the VDRL (Venereal Disease Research Laboratory under any titration. The selection of cases and controls was based on the result of the serology for syphilis using ELISA (enzyme-linked immunosorbent assay. The independent variables were grouped into: sociodemographic, behavioral, clinical and obstetric history, and health care in prenatal care and maternity hospital. Information was obtained by interview, during hospitalization, with the application of a questionnaire. Odds ratios and 95% confidence intervals were estimated using logistic regression to identify the predicting factors of the variable to be explained. RESULTS The logistic regression analysis identified as determinant factors for gestational syphilis: education level of incomplete basic education or illiterate (OR = 2.02, lack of access to telephone (OR = 2.4, catholic religion (OR = 1.70 , four or more pregnancies (OR = 2.2, three or more sexual partners in the last year (OR = 3.1, use of illicit drugs before the age of 18 (OR = 3.0, and use of illicit drugs by the current partner (OR = 1.7. Only one to three prenatal appointments (OR = 3.5 and a previous history of sexually transmitted infection (OR = 9.7 were also identified as determinant factors. CONCLUSIONS Sociodemographic, behavioral, and health care factors are associated with the occurrence of syphilis in women and should be taken into account in the elaboration of universal strategies aimed at the prevention and control of syphilis, but with a focus on situations of greater vulnerability.

  16. Risk factors for syphilis in women: case-control study

    Science.gov (United States)

    de Macêdo, Vilma Costa; de Lira, Pedro Israel Cabral; de Frias, Paulo Germano; Romaguera, Luciana Maria Delgado; Caires, Silvana de Fátima Ferreira; Ximenes, Ricardo Arraes de Alencar

    2017-01-01

    ABSTRACT OBJECTIVE To determine the sociodemographic, behavioral, and health care factors related to the occurrence of syphilis in women treated at public maternity hospitals. METHODS This is a case-control study (239 cases and 322 controls) with women admitted to seven maternity hospitals in the municipality of Recife, Brazil, from July 2013 to July 2014. Eligible women were recruited after the result of the VDRL (Venereal Disease Research Laboratory) under any titration. The selection of cases and controls was based on the result of the serology for syphilis using ELISA (enzyme-linked immunosorbent assay). The independent variables were grouped into: sociodemographic, behavioral, clinical and obstetric history, and health care in prenatal care and maternity hospital. Information was obtained by interview, during hospitalization, with the application of a questionnaire. Odds ratios and 95% confidence intervals were estimated using logistic regression to identify the predicting factors of the variable to be explained. RESULTS The logistic regression analysis identified as determinant factors for gestational syphilis: education level of incomplete basic education or illiterate (OR = 2.02), lack of access to telephone (OR = 2.4), catholic religion (OR = 1.70 ), four or more pregnancies (OR = 2.2), three or more sexual partners in the last year (OR = 3.1), use of illicit drugs before the age of 18 (OR = 3.0), and use of illicit drugs by the current partner (OR = 1.7). Only one to three prenatal appointments (OR = 3.5) and a previous history of sexually transmitted infection (OR = 9.7) were also identified as determinant factors. CONCLUSIONS Sociodemographic, behavioral, and health care factors are associated with the occurrence of syphilis in women and should be taken into account in the elaboration of universal strategies aimed at the prevention and control of syphilis, but with a focus on situations of greater vulnerability. PMID:28832758

  17. Risk Factors for Anemia in Pregnancy: A Case Control Study

    Directory of Open Access Journals (Sweden)

    Rutuja Pundkar

    2017-12-01

    Full Text Available Background: Aim of the study was to find the risk factors leading to Anemia in pregnancy. The main objective was to study the various sociodemographic factors leading to anemia. And to assess the knowledge about anemia among study participants. Material and methods: The present Case control study was carried out at Primary Health Centre, to determine the risk factors leading to anemia in pregnancy. A total of 308 pregnant females were registered. Among them two groups were made, group I cases and group II controls. Each group had 50 cases each. Laboratory test were done and females having hemoglobin less than 11mg/dl were considered anemic. Anemic females were considered cases and females having Hb >11mg/dl were considered controls. Data analysis was done using SPSS software. Results: The overall mean haemoglobin (Hb was 11.55g/dL in controls, whereas it was seen that among the cases it was 9.58g/dL.It would seem that diet, family size, education, social class, gravida and parity are associated with anemia in pregnancy. Conclusion: After adjusting for all the possible covariates there seems to be significant association between Hb levels and age group, education level, family size, diet, gravida and parity.

  18. Factores de necesidad asociados al uso adecuado del control prenatal

    Directory of Open Access Journals (Sweden)

    Clarybel Miranda Mellado

    2016-07-01

    Full Text Available Introducción: Por las implicaciones sociales de la mortalidad y morbilidad materna es importante determinar los factores de necesidad que influyen en el uso adecuado del control prenatal en gestantes de Sincelejo. Materiales y Métodos: Estudio analítico de corte transversal, que incluyó 730 gestantes, seleccionadas mediante muestreo aleatorio por conglomerados, de las comunas de la ciudad. La información fue recolectada por medio de una encuesta sociodemográfica, una ficha de uso de control prenatal y un Cuestionario para evaluar los factores de necesidad  propuestos por el Modelo de Promoción de la Salud de Nola Pender. Las gestantes fueron contactadas en sus domicilios y diligenciaron los instrumentos. Los datos fueron analizados aplicando estadística descriptiva e inferencial para determinar las asociaciones entre variables. Resultados: El 97,7% (713 de las gestantes asistía al control prenatal, con una mediana de 4 controles prenatales. Un 2,3% (17 no lo habían iniciado al momento de la encuesta y 24,4% (178 hizo uso inadecuado. El 80,7% (589 de las gestantes califican su estado de salud como bueno o muy bueno, 94,8% (692 percibieron beneficios del control prenatal. Se encontró asociación significativa entre la percepción de beneficios y el uso adecuado de control prenatal [OR=5,5 (IC 95%: 2,8 - 10,8]. Discusión y Conclusiones: La percepción que las mujeres tienen sobre los buenos resultados que reporta la asistencia al control prenatal, es el principal factor que puede explicar la adherencia al control y el cumplimiento regular de las consultas. Cómo citar este artículo: Miranda C, Castillo IY. Factores de necesidad asociados al uso adecuado del control prenatal. Rev Cuid. 2016; 7(2: 1345-51. http://dx.doi.org/10.15649/cuidarte.v7i2.340

  19. Mineral solubility and free energy controls on microbial reaction kinetics: Application to contaminant transport in the subsurface

    Energy Technology Data Exchange (ETDEWEB)

    Taillefert, Martial [Georgia Inst. of Technology, Atlanta, GA (United States); Van Cappellen, Philippe [Univ. of Waterloo, ON (Canada)

    2016-11-14

    Recent developments in the theoretical treatment of geomicrobial reaction processes have resulted in the formulation of kinetic models that directly link the rates of microbial respiration and growth to the corresponding thermodynamic driving forces. The overall objective of this project was to verify and calibrate these kinetic models for the microbial reduction of uranium(VI) in geochemical conditions that mimic as much as possible field conditions. The approach combined modeling of bacterial processes using new bioenergetic rate laws, laboratory experiments to determine the bioavailability of uranium during uranium bioreduction, evaluation of microbial growth yield under energy-limited conditions using bioreactor experiments, competition experiments between metabolic processes in environmentally relevant conditions, and model applications at the field scale. The new kinetic descriptions of microbial U(VI) and Fe(III) reduction should replace those currently used in reactive transport models that couple catabolic energy generation and growth of microbial populations to the rates of biogeochemical redox processes. The above work was carried out in collaboration between the groups of Taillefert (batch reactor experiments and reaction modeling) at Georgia Tech and Van Cappellen (retentostat experiments and reactive transport modeling) at University of Waterloo (Canada).

  20. Risk factors for gallbladder cancer: a case-control study.

    Science.gov (United States)

    Jain, Kajal; Sreenivas, V; Velpandian, T; Kapil, Umesh; Garg, Pramod Kumar

    2013-04-01

    Risk factors for gallbladder cancer (GBC) except gallstones are not well known. The objective was to study the risk factors for GBC. In a case-control study, 200 patients with GBC, 200 healthy controls and 200 gallstones patients as diseased controls were included prospectively. The risk factors studied were related to socioeconomic profile, life style, reproduction, diet and bile acids. On comparing GBC patients (mean age 51.7 years; 130 females) with healthy controls, risk factors were chemical exposure [odd ratios (OR): 7.0 (2.7-18.2); p < 0.001)], family history of gallstones [OR: 5.3 (1.5-18.9); p < 0.01)], tobacco [OR: 4.1 (1.8-9.7); p < 0.001)], fried foods [OR: 3.1 (1.7-5.6); p < 0.001], joint family [OR: 3.2 (1.7-6.2); p < 0.001], long interval between meals [OR: 1.4 (1.2-1.6); p < 0.001] and residence in Gangetic belt [OR: 3.3 (1.8-6.2); p < 0.001]. On comparing GBC cases with gallstone controls, risk factors were female gender [OR: 2.4 (1.3-4.3); p = 0.004], residence in Gangetic belt [OR: 2.3 (1.2-4.4); p = 0.012], fried foods [OR: 2.5 (1.4-4.4); p < 0.001], diabetes [OR: 2.7 (1.2-6.4); p = 0.02)], tobacco [OR 3.8 (1.7-8.1); p < 0.001)] and joint family [OR: 2.1 (1.2-3.4); p = 0.004]. The ratio of secondary to primary bile acids was significantly higher in GBC cases than gallstone controls (20.8 vs. 0.44). Fried foods, tobacco, chemical exposure, family history of gallstones, residence in Gangetic belt and secondary bile acids were significant risk factors for GBC. Copyright © 2012 UICC.

  1. Factors that control the stable carbon isotopic composition of methane produced in an anoxic marine sediment

    Science.gov (United States)

    Alperin, M. J.; Blair, Neal E.; Albert, D. B.; Hoehler, T. M.; Martens, C. S.

    1993-01-01

    The carbon isotopic composition of methane produced in anoxic marine sediment is controlled by four factors: (1) the pathway of methane formation, (2) the isotopic composition of the methanogenic precursors, (3) the isotope fractionation factors for methane production, and (4) the isotope fractionation associated with methane oxidation. The importance of each factor was evaluated by monitoring stable carbon isotope ratios in methane produced by a sediment microcosm. Methane did not accumulate during the initial 42-day period when sediment contained sulfate, indicating little methane production from 'noncompetitive' substrates. Following sulfate depletion, methane accumulation proceeded in three distinct phases. First, CO2 reduction was the dominant methanogenic pathway and the isotopic composition of the methane produced ranged from -80 to -94 per thousand. The acetate concentration increased during this phase, suggesting that acetoclastic methanogenic bacteria were unable to keep pace with acetate production. Second, acetate fermentation became the dominant methanogenic pathway as bacteria responded to elevated acetate concentrations. The methane produced during this phase was progressively enriched in C-13, reaching a maximum delta(C-13) value of -42 per thousand. Third, the acetate pool experienced a precipitous decline from greater than 5 mM to less than 20 micro-M and methane production was again dominated by CO2 reduction. The delta(C-13) of methane produced during this final phase ranged from -46 to -58 per thousand. Methane oxidation concurrent with methane production was detected throughout the period of methane accumulation, at rates equivalent to 1 to 8 percent of the gross methane production rate. Thus methane oxidation was too slow to have significantly modified the isotopic signature of methane. A comparison of microcosm and field data suggests that similar microbial interactions may control seasonal variability in the isotopic composition of methane

  2. Human factors in aviation: Terminal control area boundary conflicts

    Science.gov (United States)

    Monan, William P.

    1989-01-01

    Air-to-air conflicts in the vicinity of Terminal Control Area (TCA) boundaries were studied to obtain a better understanding of the causal dynamics of these events with particular focus on human factor issues. The study dataset consisted of 381 Instrument Flight Rules/Visual Flight Rules (IFR/VFR) traffic conflicts in airspace layers above TCA ceiling and below TCA floors; 213 reports of incursions in TCA terminal airspace by VFR aircraft, of which 123 resulted in conflicts; and an additional set of reports describing problems with Air Traffic Control (ATC) services in and around TCAs. Results and conclusions are detailed.

  3. The human factors specialist in nuclear control centre design

    International Nuclear Information System (INIS)

    Wilson, R.B.; Beattie, J.D.

    The main focus at Ontario Hydro for man-machine interface design is in the design of control centres. Because the control of a nuclear generating unit is highly centralized there is an increasing need for effective information display and control layout. Control panel design innovations such as the use of CRT displays and the extended use of computerized control in the Darlington station have made it possible for Ontario Hydro to continue to have one first operator for each generating unit. The human factors specialist involved in control panel design must deal with people who know much more about the specific systems being controlled, and must become a generalist in all these systems as well. Designers have to use conceptual techniques such as task analysis, systems design, panel mock-ups, anthropometric data, and personal judgement based on experience as they design panels. They must find a balance between becoming locked into existing technology and methods, slavishly following the latest technological trends, and forgetting that real people will be using what they design

  4. Control of exogenous factors affecting plasma homovanillic acid concentration.

    Science.gov (United States)

    Davidson, M; Giordani, A B; Mohs, R C; Mykytyn, V V; Platt, S; Aryan, Z S; Davis, K L

    1987-04-01

    Measurements of plasma homovanillic acid (pHVA) concentrations appear to be a valid research strategy in psychiatric disorders in which a central dopamine (DA) abnormality has been implicated. This study provides guidance about the control of some of the exogenous factors affecting pHVA concentrations. Fasting for 14 hours eliminates the dietary effects on pHVA in healthy human subjects. Changing position, walking for 30 minutes, or smoking two cigarettes has no effect on pHVA concentrations.

  5. Colonization Habitat Controls Biomass, Composition, and Metabolic Activity of Attached Microbial Communities in the Columbia River Hyporheic Corridor

    Energy Technology Data Exchange (ETDEWEB)

    Stern, Noah; Ginder-Vogel, Matthew; Stegen, James C.; Arntzen, Evan; Kennedy, David W.; Larget, Bret R.; Roden, Eric E.; Kostka, Joel E.

    2017-06-09

    Hydrologic exchange plays a critical role in biogeochemical cycling within the hyporheic zone (the interface between river water and groundwater) of riverine ecosystems. Such exchange may set limits on the rates of microbial metabolism and impose deterministic selection on microbial communities that adapt to dynamically changing dissolved organic carbon (DOC) sources. This study examined the response of attached microbial communities (in situcolonized sand packs) from groundwater, hyporheic, and riverbed habitats within the Columbia River hyporheic corridor to “cross-feeding” with either groundwater, river water, or DOC-free artificial fluids. Our working hypothesis was that deterministic selection duringin situcolonization would dictate the response to cross-feeding, with communities displaying maximal biomass and respiration when supplied with their native fluid source. In contrast to expectations, the major observation was that the riverbed colonized sand had much higher biomass and respiratory activity, as well as a distinct community structure, compared with those of the hyporheic and groundwater colonized sands. 16S rRNA gene amplicon sequencing revealed a much higher proportion of certain heterotrophic taxa as well as significant numbers of eukaryotic algal chloroplasts in the riverbed colonized sand. Significant quantities of DOC were released from riverbed sediment and colonized sand, and separate experiments showed that the released DOC stimulated respiration in the groundwater and piezometer colonized sand. These results suggest that the accumulation and degradation of labile particulate organic carbon (POC) within the riverbed are likely to release DOC, which may enter the hyporheic corridor during hydrologic exchange, thereby stimulating microbial activity and imposing deterministic selective pressure on the microbial community composition.

    IMPORTANCEThe influence of river water

  6. New factors controlling the balance between osteoblastogenesis and adipogenesis.

    Science.gov (United States)

    Abdallah, Basem M; Kassem, Moustapha

    2012-02-01

    The majority of conditions associated with bone loss, including aging, are accompanied by increased marrow adiposity possibly due to shifting of the balance between osteoblast and adipocyte differentiation in bone marrow stromal (skeletal) stem cells (MSC). In order to study the relationship between osteoblastogenesis and adipogenesis in bone marrow, we have characterized cellular models of multipotent MSC as well as pre-osteoblastic and pre-adipocytic cell populations. Using these models, we identified two secreted factors in the bone marrow microenviroment: secreted frizzled-related protein 1 (sFRP-1) and delta-like1 (preadipocyte factor 1) (Dlk1/Pref-1). Both exert regulatory effects on osteoblastogenesis and adipogenesis. Our studies suggest a model for lineage fate determination of MSC that is regulated through secreted factors in the bone marrow microenvironment that mediate a cross-talk between lineage committed cell populations in addition to controlling differentiation choices of multipotent MSC. Copyright © 2011 Elsevier Inc. All rights reserved.

  7. Microbial biosensors

    International Nuclear Information System (INIS)

    Le Yu; Chen, Wilfred; Mulchandani, Ashok

    2006-01-01

    A microbial biosensor is an analytical device that couples microorganisms with a transducer to enable rapid, accurate and sensitive detection of target analytes in fields as diverse as medicine, environmental monitoring, defense, food processing and safety. The earlier microbial biosensors used the respiratory and metabolic functions of the microorganisms to detect a substance that is either a substrate or an inhibitor of these processes. Recently, genetically engineered microorganisms based on fusing of the lux, gfp or lacZ gene reporters to an inducible gene promoter have been widely applied to assay toxicity and bioavailability. This paper reviews the recent trends in the development and application of microbial biosensors. Current advances and prospective future direction in developing microbial biosensor have also been discussed

  8. Stabilizing the baseline current of a microbial fuel cell-based biosensor through overpotential control under non-toxic conditions.

    Science.gov (United States)

    Stein, Nienke E; Hamelers, Hubertus V M; Buisman, Cees N J

    2010-04-01

    A MFC-based biosensor can act as online toxicity sensor. Electrical current is a direct linear measure for metabolic activity of electrochemically active microorganisms. Microorganisms gain energy from anodic overpotential and current strongly depends on anodic overpotential. Therefore control of anodic overpotential is necessary to detect toxic events and prevent false positive alarms. Anodic overpotential and thus current is influenced by anode potential, pH, substrate and bicarbonate concentrations. In terms of overpotential all factor showed a comparable effect, anode potential 1.2% change in current density per mV, pH 0.43%/mV, bicarbonate 0.75%/mV and acetate 0.8%/mV. At acetate saturation the maximum acetate conversion rate is reached and with that a constant bicarbonate concentration. Control of acetate and bicarbonate concentration can be less strict than control of anode potential and pH. Current density changes due to changing anode potential and pH are in the same order of magnitude as changes due to toxicity. Strict control of pH and anode potential in a small range is required. The importance of anodic overpotential control for detection of toxic compounds is shown. To reach a stable baseline current under nontoxic conditions a MFC-based biosensor should be operated at controlled anode potential, controlled pH and saturated substrate concentrations. 2009 Elsevier B.V. All rights reserved.

  9. Mitochondrial respiratory control is lost during growth factor deprivation.

    Science.gov (United States)

    Gottlieb, Eyal; Armour, Sean M; Thompson, Craig B

    2002-10-01

    The ability of cells to maintain a bioenergetically favorable ATP/ADP ratio confers a tight balance between cellular events that consume ATP and the rate of ATP production. However, after growth factor withdrawal, the cellular ATP/ADP ratio declines. To investigate these changes, mitochondria from growth factor-deprived cells isolated before the onset of apoptosis were characterized in vitro. Mitochondria from growth factor-deprived cells have lost their ability to undergo matrix condensation in response to ADP, which is accompanied by a failure to perform ADP-coupled respiration. At the time of analysis, mitochondria from growth factor-deprived cells were not depleted of cytochrome c and cytochrome c-dependent respiration was unaffected, demonstrating that the inhibition of the respiratory rate is not due to loss of cytochrome c. Agents that disrupt the mitochondrial outer membrane, such as digitonin, or maintain outer membrane exchange of adenine nucleotide, such as Bcl-x(L), restored ADP-dependent control of mitochondrial respiration. Together, these data suggest that the regulation of mitochondrial outer membrane permeability contributes to respiratory control.

  10. Environment of care: Is it time to reassess microbial contamination of the operating room air as a risk factor for surgical site infection in total joint arthroplasty?

    Science.gov (United States)

    Parvizi, Javad; Barnes, Sue; Shohat, Noam; Edmiston, Charles E

    2017-11-01

    In the modern operating room (OR), traditional surgical mask, frequent air exchanges, and architectural barriers are viewed as effective in reducing airborne microbial populations. Intraoperative sampling of airborne particulates is rarely performed in the OR because of technical difficulties associated with sampling methodologies and a common belief that airborne contamination is infrequently associated with surgical site infections (SSIs). Recent studies suggest that viable airborne particulates are readily disseminated throughout the OR, placing patients at risk for postoperative SSI. In 2017, virtually all surgical disciplines are engaged in the implantation of selective biomedical devices, and these implants have been documented to be at high risk for intraoperative contamination. Approximately 1.2 million arthroplasties are performed annually in the United States, and that number is expected to increase to 3.8 million by the year 2030. The incidence of periprosthetic joint infection is perceived to be low (<2.5%); however, the personal and fiscal morbidity is significant. Although the pharmaceutic and computer industries enforce stringent air quality standards on their manufacturing processes, there is currently no U.S. standard for acceptable air quality within the OR environment. This review documents the contribution of air contamination to the etiology of periprosthetic joint infection, and evidence for selective innovative strategies to reduce the risk of intraoperative microbial aerosols. Copyright © 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  11. Biotechnological Aspects of Microbial Extracellular Electron Transfer

    Science.gov (United States)

    Kato, Souichiro

    2015-01-01

    Extracellular electron transfer (EET) is a type of microbial respiration that enables electron transfer between microbial cells and extracellular solid materials, including naturally-occurring metal compounds and artificial electrodes. Microorganisms harboring EET abilities have received considerable attention for their various biotechnological applications, in addition to their contribution to global energy and material cycles. In this review, current knowledge on microbial EET and its application to diverse biotechnologies, including the bioremediation of toxic metals, recovery of useful metals, biocorrosion, and microbial electrochemical systems (microbial fuel cells and microbial electrosynthesis), were introduced. Two potential biotechnologies based on microbial EET, namely the electrochemical control of microbial metabolism and electrochemical stimulation of microbial symbiotic reactions (electric syntrophy), were also discussed. PMID:26004795

  12. Biological stability of drinking water : Controlling factors, methods, and challenges

    NARCIS (Netherlands)

    Prest, E.I.E.D.; Hammes, F.; Van Loosdrecht, M.C.M.; Vrouwenvelder, J.S.

    2016-01-01

    Biological stability of drinking water refers to the concept of providing consumers with drinking water of same microbial quality at the tap as produced at the water treatment facility. However, uncontrolled growth of bacteria can occur during distribution in water mains and premise plumbing, and

  13. Wind tunnel testing to predict control room atmospheric dispersion factors

    International Nuclear Information System (INIS)

    Holmquist, L.J.; Harden, P.A.; Muraida, J.E.

    1993-01-01

    Recent concerns at Palisades about control room habitability in the event of a loss-of-coolant accident have led to an extensive effort to increase control room habitability margin. The heating, ventilating and air-conditioning (HVAC) system servicing the control room has the potential for unfiltered in-leakage through its normal outside air intake louvered isolation dampers during emergency mode. The current limiting control room habitability analysis allows for 1.2 x 10 -2 m 3 /s (25 ft 3 /min) unfiltered in-leakage into the control room envelope. This leakage value was not thought to be achievable with the existing as-built configuration. Repairing the system was considered as a potential solution; however, this would be costly and could negatively affect plant operation. In addition, the system would still be required to meet the low specified unfiltered in-leakage. A second approach to this problem was to determine the atmospheric dispersion factors (x/Q's) through a wind tunnel test using a scale model of Palisades. The results of the wind tunnel testing could yield more realistic x/Q's for control room habitability than previously employed methods. Palisades selected the wind tunnel study option based on its ease of implementation, realistic results, and low cost. More importantly, the results of the study could increase the allowable unfiltered in-leakage

  14. Cooperative research for human factors review of advanced control rooms

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jung Woon; Park, Jae Chang; Lee, Yong Hee; Oh, In Seok; Lee, Hyun Chul

    2000-12-01

    This project has been performed as cooperative research between KAERI and USNRC. Human factors issues related to soft controls, which is one of key features of advanced HSI, are identified in this project. The issues are analyzed for the evaluation approaches in either experimental or analytical ways. Also, issues requiring additional researches for the evaluation of advanced HSI are identified in the areas of advanced information systems design, computer-based procedure systems, soft controls, human systems interface and plant modernization process, and maintainability of digital systems. The issues are analyzed to discriminate the urgency of researches on it to high, medium, and low levels in consideration of advanced HSI development status in Korea, and some of the issues that can be handled by experimental researches are identified. Additionally, an experimental study is performed to compare operator's performance on human error detection in advanced control rooms vs. in conventional control rooms. It is found that advanced control rooms have several design characteristics hindering operator's error detection performance compared to conventional control rooms.

  15. Cooperative research for human factors review of advanced control rooms

    International Nuclear Information System (INIS)

    Lee, Jung Woon; Park, Jae Chang; Lee, Yong Hee; Oh, In Seok; Lee, Hyun Chul

    2000-12-01

    This project has been performed as cooperative research between KAERI and USNRC. Human factors issues related to soft controls, which is one of key features of advanced HSI, are identified in this project. The issues are analyzed for the evaluation approaches in either experimental or analytical ways. Also, issues requiring additional researches for the evaluation of advanced HSI are identified in the areas of advanced information systems design, computer-based procedure systems, soft controls, human systems interface and plant modernization process, and maintainability of digital systems. The issues are analyzed to discriminate the urgency of researches on it to high, medium, and low levels in consideration of advanced HSI development status in Korea, and some of the issues that can be handled by experimental researches are identified. Additionally, an experimental study is performed to compare operator's performance on human error detection in advanced control rooms vs. in conventional control rooms. It is found that advanced control rooms have several design characteristics hindering operator's error detection performance compared to conventional control rooms

  16. The factors controlling species density in herbaceous plant communities: An assessment

    Science.gov (United States)

    Grace, J.B.

    1999-01-01

    This paper evaluates both the ideas and empirical evidence pertaining to the control of species density in herbaceous plant communities. While most theoretical discussions of species density have emphasized the importance of habitat productivity and disturbance regimes, many other factors (e.g. species pools, plant litter accumulation, plant morphology) have been proposed to be important. A review of literature presenting observations on the density of species in small plots (in the vicinity of a few square meters or less), as well as experimental studies, suggests several generalizations: (1) Available data are consistent with an underlying unimodal relationship between species density and total community biomass. While variance in species density is often poorly explained by predictor variables, there is strong evidence that high levels of community biomass are antagonistic to high species density. (2) Community biomass is just one of several factors affecting variations in species density. Multivariate analyses typically explain more than twice as much variance in species density as can be explained by community biomass alone. (3) Disturbance has important and sometimes complex effects on species density. In general, the evidence is consistent with the intermediate disturbance hypothesis but exceptions exist and effects can be complex. (4) Gradients in the species pool can have important influences on patterns of species density. Evidence is mounting that a considerable amount of the observed variability in species density within a landscape or region may result from environmental effects on the species pool. (5) Several additional factors deserve greater consideration, including time lags, species composition, plant morphology, plant density and soil microbial effects. Based on the available evidence, a conceptual model of the primary factors controlling species density is presented here. This model suggests that species density is controlled by the effects of

  17. Microbially induced carbonate precipitation (MICP) by denitrification as ground improvement method - Process control in sand column experiments

    Science.gov (United States)

    Pham, Vinh; van Paassen, Leon; Nakano, Akiko; Kanayama, Motohei; Heimovaara, Timo

    2013-04-01

    Calcite precipitation induced by microbes has been proven to be efficient in stabilizing granular soils, especially with urea hydrolysis, as it has been successfully demonstrated in a pilot application 2010. However, as a byproduct highly concentrated ammonium chloride (NH4Cl) solution is produced, which has to be removed and disposed and forms a significant disadvantage of the technique that makes an alternative process like denitrification preferred. The proof of principle of microbially induced calcite precipitation (MICP) by denitrification has been demonstrated by Van Paassen et al (2010) who suggested that instead of producing waste as a byproduct, different pre-treated waste streams could be used as substrates for in situ growth of denitrifying bacteria and simultaneous cementation without producing waste to be removed. In this study sand column experiments are performed in which calcium carbonate was successfully precipitated by indigenous denitrifying micro-organisms, which were supplied weekly with a pulse of a substrate solution containing calcium acetate and calcium nitrate. Besides the production of calcite and the growth of bacteria in biofilms, the reduction of nitrate resulted in the production of (nitrogen) gas. It was observed that this gas partly fills up the pore space and consequently contributed to a reduction of the permeability of the treated sand. The presence of gas in the pore space affected the flow of the injected substrates and influenced to the distribution of calcium carbonate. The effect of the mean particle size (D50) on the flow and transport of solutes and gas in the porous media has been evaluated by treating several columns with varying grain size distribution and comparing the change in permeability after each incubation period and analyzing the distribution of the gas throughout the columns using X-ray computed tomography (CT) scanning. The present results show that there is a considerable decrease of permeability - a

  18. Risk Factors For Ectopic Pregnancy : A Case Control Study

    Directory of Open Access Journals (Sweden)

    Deshmukh J.S

    1999-01-01

    Full Text Available Research question: Which are the risk factors for ectopic pregnancy . Objective: To study the strength of association between hypothesised risk factors and ectopic pregnancy. Study design: Unmatched case- control study. Setting: Government Medical College, Hospital, Nagpur. Participants: 133 cases of ectopic pregnancy and equal number of controls (non pregnant women admitted to study hospital. Study variables : Pelvic inflammatory diseases, sexually transmitted diseases, IUD use at conception , past use of IUD, prior ectopic pregnancy, OC pills use at the time of conception, past use of OC pills, induced abortion, spontaneous abortion, infertility and pelvic and abdominal surgery. Statistical analysis: Odds ratios & their 95% CI, Pearson’s chi square test, unconditional logistic regression analysis and population attributable risk proportion. Results : Use of IUD at conception, prior ectopic pregnancy , pelvic inflammatory disease, sexually transmitted diseases, infertility, OC pills use at the time of conception, past use of IUD and induced abortion were found to be significantly associated with ectopic pregnancy. Conclusion: Identification of these risk factors for etopic pregnancy shall help in early detection and appropriate management in an individual case and it may help in devising a comprehensive preventive strategy for ectopic pregnancy

  19. Systems biology of microbial exopolysaccharides production

    Directory of Open Access Journals (Sweden)

    Ozlem eAtes

    2015-12-01

    Full Text Available Exopolysaccharides (EPS produced by diverse group of microbial systems are rapidly emerging as new and industrially important biomaterials. Due to their unique and complex chemical structures and many interesting physicochemical and rheological properties with novel functionality, the microbial EPSs find wide range of commercial applications in various fields of the economy such as food, feed, packaging, chemical, textile, cosmetics and pharmaceutical industry, agriculture and medicine. EPSs are mainly associated with high-value applications and they have received considerable research attention over recent decades with their biocompatibility, biodegradability, and both environmental and human compatibility. However only a few microbial EPSs have achieved to be used commercially due to their high production costs. The emerging need to overcome economic hurdles and the increasing significance of microbial EPSs in industrial and medical biotechnology call for the elucidation of the interrelations between metabolic pathways and EPS biosynthesis mechanism in order to control and hence enhance its microbial productivity. Moreover a better understanding of biosynthesis mechanism is a significant issue for improvement of product quality and properties and also for the design of novel strains. Therefore a systems-based approach constitutes an important step towards understanding the interplay between metabolism and EPS biosynthesis and further enhances its metabolic performance for industrial application. In this review, primarily the microbial EPSs, their biosynthesis mechanism and important factors for their production will be discussed. After this brief introduction, recent literature on the application of omics technologies and systems biology tools for the improvement of production yields will be critically evaluated. Special focus will be given to EPSs with high market value such as xanthan, levan, pullulan and dextran.

  20. Systems Biology of Microbial Exopolysaccharides Production.

    Science.gov (United States)

    Ates, Ozlem

    2015-01-01

    Exopolysaccharides (EPSs) produced by diverse group of microbial systems are rapidly emerging as new and industrially important biomaterials. Due to their unique and complex chemical structures and many interesting physicochemical and rheological properties with novel functionality, the microbial EPSs find wide range of commercial applications in various fields of the economy such as food, feed, packaging, chemical, textile, cosmetics and pharmaceutical industry, agriculture, and medicine. EPSs are mainly associated with high-value applications, and they have received considerable research attention over recent decades with their biocompatibility, biodegradability, and both environmental and human compatibility. However, only a few microbial EPSs have achieved to be used commercially due to their high production costs. The emerging need to overcome economic hurdles and the increasing significance of microbial EPSs in industrial and medical biotechnology call for the elucidation of the interrelations between metabolic pathways and EPS biosynthesis mechanism in order to control and hence enhance its microbial productivity. Moreover, a better understanding of biosynthesis mechanism is a significant issue for improvement of product quality and properties and also for the design of novel strains. Therefore, a systems-based approach constitutes an important step toward understanding the interplay between metabolism and EPS biosynthesis and further enhances its metabolic performance for industrial application. In this review, primarily the microbial EPSs, their biosynthesis mechanism, and important factors for their production will be discussed. After this brief introduction, recent literature on the application of omics technologies and systems biology tools for the improvement of production yields will be critically evaluated. Special focus will be given to EPSs with high market value such as xanthan, levan, pullulan, and dextran.

  1. Comparison of atherogenic risk factors among poorly controlled and well-controlled adolescent phenylketonuria patients.

    Science.gov (United States)

    Gündüz, Mehmet; Çakar, Sevim; Kuyum, Pınar; Makay, Balahan; Arslan, Nur

    2016-06-01

    Previous studies investigating the known risk factors of atherosclerosis in phenylketonuria patients have shown conflicting results. The primary aim of our study was to investigate the serum atherogenic markers in adolescent classical phenylketonuria patients and compare these parameters with healthy peers. The secondary aim was to compare these atherogenic markers in well-controlled and poorly controlled patients. A total of 59 patients (median age: 12.6 years, range: 11-17 years) and 44 healthy controls (median age: 12.0 years, range: 11-15 years) were enrolled in our study. Phenylketonuria patients were divided into two groups: well-controlled (serum phenylalanine levels below 360 µmol/L; 24 patients) and poorly controlled patients (serum phenylalanine levels higher than 360 µmol/L). The mean high-density lipoprotein cholesterol levels of well-controlled patients (1.0±0.2 mmol/L) were significantly lower compared with poorly controlled patients and controls (1.1±0.2 mmol/L, p=0.011 and 1.4±0.2 mmol/L, pphenylketonuria patients. In particular, these changes were more prominent in well-controlled patients. We conclude that phenylketonuria patients might be at risk for atherosclerosis, and therefore screening for atherosclerotic risk factors should be included in the phenylketonuria therapy and follow-up in addition to other parameters.

  2. Quality control in the development of coagulation factor concentrates.

    Science.gov (United States)

    Snape, T J

    1987-01-01

    Limitation of process change is a major factor contributing to assurance of quality in pharmaceutical manufacturing. This is particularly true in the manufacture of coagulation factor concentrates, for which presumptive testing for poorly defined product characteristics is an integral feature of finished product quality control. The development of new or modified preparations requires that this comfortable position be abandoned, and that the effect on finished product characteristics of changes to individual process steps (and components) be assessed. The degree of confidence in the safety and efficacy of the new product will be determined by, amongst other things, the complexity of the process alteration and the extent to which the results of finished product tests can be considered predictive. The introduction of a heat-treatment step for inactivation of potential viral contaminants in coagulation factor concentrates presents a significant challenge in both respects, quite independent of any consideration of assessment of the effectiveness of the viral inactivation step. These interactions are illustrated by some of the problems encountered with terminal dry heat-treatment (72 h. at 80 degrees C) of factor VIII and prothrombin complex concentrates manufactured by the Blood Products Laboratory.

  3. Physical factors controlling the ductility of bulk metallic glasses

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y. [Central South University, China; Liu, Chain T [ORNL; Zhang, Z. [University of Tennessee, Knoxville (UTK); Keppens, V. [University of Tennessee, Knoxville (UTK)

    2008-01-01

    In order to identify key physical factor controlling the deformation and fracture behavior of bulk metallic glasses (BMGs), we compiled and analyzed the elastic moduli and compressive ductility for BMGs. In addition, new modulus data were generated in the critical ranges in order to facilitate the analysis. We have found that the intrinsic ductility of BMGs can be correlated with the bulk-to-shear modulus ratio B/G according to Pugh's [Philos. Mag. 45, 823 (1954) ] rule. In some individual BMG systems, for example, Fe based, the relationship seems to be very clear. The physical meaning of this correlation is discussed in terms of atomic bonding and connectivity.

  4. Identification of controlling factors for the initiation of corrosion of fresh concrete sewers.

    Science.gov (United States)

    Jiang, Guangming; Sun, Xiaoyan; Keller, Jurg; Bond, Philip L

    2015-09-01

    The development of concrete corrosion in new sewer pipes undergoes an initiation process before reaching an active corrosion stage. This initiation period is assumed to last several months to years but the key factors affecting the process, and its duration, are not well understood. This study is therefore focused on this initial stage of the corrosion process and the effect of key environmental factors. Such knowledge is important for the effective management of corrosion in new sewers, as every year of life extension of such systems has a very high financial benefit. This long-term (4.5 year) study has been conducted in purpose-built corrosion chambers that closely simulated the sewer environment, but with control of three key environmental factors being hydrogen sulfide (H2S) gas phase concentration, relative humidity and air temperature. Fresh concrete coupons, cut from an industry-standard sewer pipe, were exposed to the corrosive conditions in the chambers, both in the gas phase and partially submerged in wastewater. A total of 36 exposure conditions were investigated to determine the controlling factors by regular retrieval of concrete coupons for detailed analysis of surface pH, sulfur compounds (elemental sulfur and sulfate) and concrete mass loss. Corrosion initiation times were thus determined for different exposure conditions. It was found that the corrosion initiation time of both gas-phase and partially-submerged coupons was positively correlated with the gas phase H2S concentration, but only at levels of 10 ppm or below, indicating that sulfide oxidation rate rather than the H2S concentration was the limiting factor during the initiation stage. Relative humidity also played a role for the corrosion initiation of the gas-phase coupons. However, the partially-submerged coupons were not affected by humidity as these coupons were in direct contact with the sewage and hence did have sufficient moisture to enable the microbial processes to proceed. The

  5. Environmental and microbial factors influencing methane and nitrous oxide fluxes in Mediterranean cork oak woodlands: trees make a difference.

    Science.gov (United States)

    Shvaleva, Alla; Siljanen, Henri M P; Correia, Alexandra; Costa E Silva, Filipe; Lamprecht, Richard E; Lobo-do-Vale, Raquel; Bicho, Catarina; Fangueiro, David; Anderson, Margaret; Pereira, João S; Chaves, Maria M; Cruz, Cristina; Martikainen, Pertti J

    2015-01-01

    Cork oak woodlands (montado) are agroforestry systems distributed all over the Mediterranean basin with a very important social, economic and ecological value. A generalized cork oak decline has been occurring in the last decades jeopardizing its future sustainability. It is unknown how loss of tree cover affects microbial processes that are consuming greenhouse gases in the montado ecosystem. The study was conducted under two different conditions in the natural understory of a cork oak woodland in center Portugal: under tree canopy (UC) and open areas without trees (OA). Fluxes of methane and nitrous oxide were measured with a static chamber technique. In order to quantify methanotrophs and bacteria capable of nitrous oxide consumption, we used quantitative real-time PCR targeting the pmoA and nosZ genes encoding the subunit of particulate methane mono-oxygenase and catalytic subunit of the nitrous oxide reductase, respectively. A significant seasonal effect was found on CH4 and N2O fluxes and pmoA and nosZ gene abundance. Tree cover had no effect on methane fluxes; conversely, whereas the UC plots were net emitters of nitrous oxide, the loss of tree cover resulted in a shift in the emission pattern such that the OA plots were a net sink for nitrous oxide. In a seasonal time scale, the UC had higher gene abundance of Type I methanotrophs. Methane flux correlated negatively with abundance of Type I methanotrophs in the UC plots. Nitrous oxide flux correlated negatively with nosZ gene abundance at the OA plots in contrast to that at the UC plots. In the UC soil, soil organic matter had a positive effect on soil extracellular enzyme activities, which correlated positively with the N2O flux. Our results demonstrated that tree cover affects soil properties, key enzyme activities and abundance of microorganisms and, consequently net CH4 and N2O exchange.

  6. Design of neural network model-based controller in a fed-batch microbial electrolysis cell reactor for bio-hydrogen gas production

    Science.gov (United States)

    Azwar; Hussain, M. A.; Abdul-Wahab, A. K.; Zanil, M. F.; Mukhlishien

    2018-03-01

    One of major challenge in bio-hydrogen production process by using MEC process is nonlinear and highly complex system. This is mainly due to the presence of microbial interactions and highly complex phenomena in the system. Its complexity makes MEC system difficult to operate and control under optimal conditions. Thus, precise control is required for the MEC reactor, so that the amount of current required to produce hydrogen gas can be controlled according to the composition of the substrate in the reactor. In this work, two schemes for controlling the current and voltage of MEC were evaluated. The controllers evaluated are PID and Inverse neural network (NN) controller. The comparative study has been carried out under optimal condition for the production of bio-hydrogen gas wherein the controller output is based on the correlation of optimal current and voltage to the MEC. Various simulation tests involving multiple set-point changes and disturbances rejection have been evaluated and the performances of both controllers are discussed. The neural network-based controller results in fast response time and less overshoots while the offset effects are minimal. In conclusion, the Inverse neural network (NN)-based controllers provide better control performance for the MEC system compared to the PID controller.

  7. Human factors in remote control engineering development activities

    International Nuclear Information System (INIS)

    Clarke, M.M.; Hamel, W.R.; Draper, J.V.

    1983-01-01

    Human factors engineering, which is an integral part of the advanced remote control development activities at the Oak Ridge National Laboratory, is described. First, work at the Remote Systems Development Facility (RSDF) has shown that operators can perform a wide variety of tasks, some of which were not specifically designed for remote systems, with a dextrous electronic force-reflecting servomanipulator and good television remote viewing capabilities. Second, the data collected during mock-up remote maintenance experiments at the RSDF have been analyzed to provide guidelines for the design of human interfaces with an integrated advanced remote maintenance system currently under development. Guidelines have been provided for task allocation between operators, remote viewing systems, and operator controls. 6 references, 5 figures, 2 tables

  8. Factors Controlling Nanoparticle Pharmacokinetics: An Integrated Analysis and Perspective

    DEFF Research Database (Denmark)

    Moghimi, Seyed Moien; Hunter, A.C.; Andresen, T.L.

    2012-01-01

    of interrelated core and interfacial physicochemical and biological factors. Pertinent to realizing therapeutic goals, definitive maps that establish the interdependency of nanoparticle size, shape, and surface characteristics in relation to interfacial forces, biodistribution, controlled drug release, excretion......Intravenously injected nanoparticulate drug carriers provide a wide range of unique opportunities for site-specific targeting of therapeutic agents to many areas within the vasculature and beyond. Pharmacokinetics and biodistribution of these carriers are controlled by a complex array...... are already on the market and many are in late-phase clinical trials. With concomitant advances in extensive computational knowledge of the genomics and epigenomics of interindividual variations in drug responses, the boundaries toward development of personalized nanomedicines can be pushed further....

  9. Understanding disease control: influence of epidemiological and economic factors.

    Directory of Open Access Journals (Sweden)

    Katarzyna Oleś

    Full Text Available We present a model of disease transmission on a regular and small world network and compare different control options. Comparison is based on a total cost of epidemic, including cost of palliative treatment of ill individuals and preventive cost aimed at vaccination or culling of susceptible individuals. Disease is characterized by pre-symptomatic phase, which makes detection and control difficult. Three general strategies emerge: global preventive treatment, local treatment within a neighborhood of certain size and only palliative treatment with no prevention. While the choice between the strategies depends on a relative cost of palliative and preventive treatment, the details of the local strategy and, in particular, the size of the optimal treatment neighborhood depend on the epidemiological factors. The required extent of prevention is proportional to the size of the infection neighborhood, but depends on time till detection and time till treatment in a non-nonlinear (power law. The optimal size of control neighborhood is also highly sensitive to the relative cost, particularly for inefficient detection and control application. These results have important consequences for design of prevention strategies aiming at emerging diseases for which parameters are not nessecerly known in advance.

  10. Non-target effects of the microbial control agents Pseudomonas fluorescens DR54 and Clonostachys rosea IK726 in soils cropped with barley followed by sugar beet: a greenhouse assessment

    DEFF Research Database (Denmark)

    Johansen, A.; Knudsen, I. M. B.; Binnerup, S. J.

    2005-01-01

    Non-target effects of a bacterial (Pseudomonas fluorescens DR54) and a fungal (Clonostachys rosea IK726) microbial control agent (MCA), on the indigenous microbiota in bulk soil and rhizosphere of barley, and subsequent a sugar beet crop, were studied in a greenhouse experiment. MCAs were...... introduced by seed and soil inoculation. Bulk and rhizosphere soils were sampled regularly during the growth of barley and sugar beet. The soils were assayed for the fate of MCAs and various features of the indigenous soil microbiota. At the end of the experiment (193 d), DR54 and IK726 had declined...... by a factor of 106 and 20, respectively, and DR54 showed a short-lasting growth increase in the sugar beet rhizosphere. In general, the non-target effects were small and transient. IK726 seemed to have general stimulating effects on soil enzyme activity and the soil microbiota, and resulted in a significant...

  11. Soil pH, total phosphorus, climate and distance are the major factors influencing microbial activity at a regional spatial scale

    DEFF Research Database (Denmark)

    Cao, Haichuan; Chen, Ruirui; Wang, Libing

    2016-01-01

    Considering the extensive functional redundancy in microbial communities and great difficulty in elucidating it based on taxonomic structure, studies on the biogeography of soil microbial activity at large spatial scale are as important as microbial community structure. Eighty-four soil samples...... scaling clearly revealed that soil microbial activities showed distinct differentiation at different sites over a regional spatial scale, which were strongly affected by soil pH, total P, rainfall, temperature, soil type and location. In addition, microbial community structure was greatly influenced...... scales. There are common (distance, climate, pH and soil type) but differentiated aspects (TP, SOC and N) in the biogeography of soil microbial community structure and activity....

  12. Hormonal and dietary factors in acne vulgaris versus controls.

    Science.gov (United States)

    Stewart, Thomas Jonathan; Bazergy, Carl

    2018-01-01

    Background : Acne vulgaris is an inflammatory skin disorder with not as yet fully understood pathogenesis. In this controlled study, we assessed acne vulgaris patients for several possible pathogenic factors such as vitamin D deficiency, vegan diet, increased body mass index (BMI) and positive anti-transglutaminase antibody. Methods : We screened 10 years of records at a family medicine clinic for patients diagnosed with acne vulgaris. In eligible subjects, we collected data regarding 25-hydroxylvitamin D levels, BMI, dietary preference and serum IgA tissue transglutaminase levels. Controls were age- (+/- 12 months) and sex-matched patients seen during the study period without a diagnosis of acne vulgaris. Results : 453 patients were given a diagnosis of acne vulgaris during the study period. Compared with controls, we found significant associations between vitamin D deficiency (4.0U/mL) and a diagnosis of acne vulgaris. Conclusions : Our study adds important information to the current body of literature in pursuit of elucidating the pathogenesis of this complex multifactorial disease.

  13. Efficient simultaneous partial nitrification, anammox and denitrification (SNAD) system equipped with a real-time dissolved oxygen (DO) intelligent control system and microbial community shifts of different substrate concentrations.

    Science.gov (United States)

    Wen, Xin; Gong, Benzhou; Zhou, Jian; He, Qiang; Qing, Xiaoxia

    2017-08-01

    Simultaneous partial nitrification, anammox and denitrification (SNAD) process was studied in a sequencing batch biofilm reactor (SBBR) fed with synthetic wastewater in a range of 2200 mgN/L ∼ 50 mgN/L. Important was an external real-time precision dissolved oxygen (DO) intelligent control system that consisted of feed forward control system and feedback control system. This DO control system permitted close control of oxygen supply according to influent concentration, effluent quality and other environmental factors in the reactor. In this study the operation was divided into six phases according to influent nitrogen applied. SNAD system was successfully set up after adding COD into a CANON system. And the presence of COD enabled the survival of denitrifiers, and made Thauera and Pseudomonas predominant as functional denitrifiers in this system. Denaturing gradient gel electrophoresis (DGGE), fluorescence in situ hybridization (FISH) and 16S rRNA amplicon pyrosequencing were used to analyze the microbial variations of different substrate concentrations. Results indicated that the relative population of ammonia oxidizing bacteria (AOB) members decreased when influent ammonia concentration decreased from 2200 mg/L to 50 mg/L, while no dramatic drop of the percent of anammox bacteria was seen. And Nitrosomonas europaea was the predominant AOB in SNAD system treating sewage, while Candidatus Brocadia was the dominant anammox bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Microbial glycoproteomics

    DEFF Research Database (Denmark)

    Halim, Adnan; Anonsen, Jan Haug

    2017-01-01

    Mass spectrometry-based "-omics" technologies are important tools for global and detailed mapping of post-translational modifications. Protein glycosylation is an abundant and important post translational modification widespread throughout all domains of life. Characterization of glycoproteins...... and research in this area is rapidly accelerating. Here, we review recent developments in glycoproteomic technologies with a special focus on microbial protein glycosylation....

  15. Seasonal variability of microbial biomass phosphorus in urban soils.

    Science.gov (United States)

    Halecki, W; Gąsiorek, M

    2015-01-01

    Urban soils have been formed through human activities. Seasonal evaluation with time-control procedure are essential for plant, and activity of microorganisms. Therefore, these processes are crucial in the urban area due to geochemical changes in the past years. The purpose of this study was to investigate the changes of content of microbial biomass phosphorus (P) in the top layer of soils throughout the season. In this research, the concentration of microbial biomass P ranged from 0.01 to 6.29 mg·kg(-1). We used single-factor repeated-measure analysis of variance to test the effect of season on microbial biomass P content of selected urban soils. We found no statistically significant differences between the concentration of microbial biomass P in the investigated urban and sub-urban soils during the growing season. This analysis explicitly recognised that environmental urban conditions are steady. Specifically, we have studied how vegetation seasonality and ability of microbial biomass P are useful for detecting quality deviations, which affect the equilibrium of urban soil. In conclusion, seasonal variability of the stringency of assurance across the different compounds of soil reveals, as expected, the stable condition of the urban soils. Seasonal responses in microbial biomass P under urban soil use should establish a framework as a reference to the activity of the microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Unlocking Ft: Modeling thermodynamic controls and isotope fractionation factors in nutrient limited environments

    Science.gov (United States)

    Druhan, J. L.; Giannetta, M.; Sanford, R. A.

    2017-12-01

    In recent years, reactive transport principles have expanded from early applications, largely based in contaminant hydrology, to a wide range of biologically mediated redox environments including marine sedimentary diagenesis, terrestrial metal ore deposits, soils, and critical zone weathering profiles. A common observation across this diversity of systems is that they often function under energetically limited conditions in comparison to those typical of contaminated aquifers subject to engineered remediation techniques. As a result, the kinetic rate expressions traditionally employed within reactive transport frameworks to simulate microbially mediated redox transformations have required modification. This was recognized in a series of seminal papers by Jin and Bethke (2005, 2007) in which the authors expanded upon a Monod rate law to include a thermodynamic potential factor `Ft' which exerts a limitation on the overall rate based on the thermodynamic driving force of the electron transfer reaction. This new rate expression is now commonly implemented within many of the major reactive transport software packages, though appropriate application has yet to be thoroughly demonstrated. Notably, the characteristically large partitioning of stable isotopes during microbially mediated reactions, which is extensively utilized to identify and quantify these redox transformations, has yet to be simulated under conditions in which the Ft term may be expected to exert a significant mass dependent influence. Here, we develop a series of simplified simulations for the microbially mediated reduction of sulfate based on the datasets reported by Jin and Bethke, and apply appropriate mass-bias within the Ft term to consider the extent to which the resulting isotopic fractionation is consistent with that observed in energetically limited systems. We show that the Ft term can exert a significant influence on the observed fractionation factor under common environmental conditions

  17. Ets transcription factor GABP controls T cell homeostasis and immunity.

    Science.gov (United States)

    Luo, Chong T; Osmanbeyoglu, Hatice U; Do, Mytrang H; Bivona, Michael R; Toure, Ahmed; Kang, Davina; Xie, Yuchen; Leslie, Christina S; Li, Ming O

    2017-10-20

    Peripheral T cells are maintained in the absence of vigorous stimuli, and respond to antigenic stimulation by initiating cell cycle progression and functional differentiation. Here we show that depletion of the Ets family transcription factor GA-binding protein (GABP) in T cells impairs T-cell homeostasis. In addition, GABP is critically required for antigen-stimulated T-cell responses in vitro and in vivo. Transcriptome and genome-wide GABP-binding site analyses identify GABP direct targets encoding proteins involved in cellular redox balance and DNA replication, including the Mcm replicative helicases. These findings show that GABP has a nonredundant role in the control of T-cell homeostasis and immunity.

  18. Initial Gut Microbial Composition as a Key Factor Driving Host Response to Antibiotic Treatment, as Exemplified by the Presence or Absence of Commensal Escherichia coli.

    Science.gov (United States)

    Ju, Tingting; Shoblak, Yasmeen; Gao, Yanhua; Yang, Kaiyuan; Fouhse, Janelle; Finlay, B Brett; So, Yee Wing; Stothard, Paul; Willing, Benjamin P

    2017-09-01

    Antibiotics are important for treating bacterial infection; however, efficacies and side effects of antibiotics vary in medicine and experimental models. A few studies have correlated microbiota composition variations with health outcomes in response to antibiotics; however, no study has demonstrated causality. We had noted variation in colonic expression of C-type lectins, regenerating islet-derived protein 3β (Reg3β) and Reg3γ, after metronidazole treatment in a mouse model. To investigate the effects of specific variations in the preexisting microbiome on host response to antibiotics, mice harboring a normal microbiota were allocated to 4 treatments in a 2-by-2 factorial arrangement with or without commensal Escherichia coli and with or without metronidazole in drinking water. E. coli colonized readily without causing a notable shift in the microbiota or host response. Metronidazole administration reduced microbiota biodiversity, indicated by decreased Chao1 and Shannon index values, and altered microbiota composition. However, the presence of E. coli strongly affected metronidazole-induced microbiota shifts. Remarkably, this single commensal bacterium in the context of a complex population led to variations in host responses to metronidazole treatment, including increased expression of antimicrobial peptides Reg3β and Reg3γ and intestinal inflammation indicated by tumor necrosis factor alpha levels. Similar results were obtained from 2-week antibiotic exposure and with additional E. coli isolates. The results of this proof-of-concept study indicate that even minor variations in initial commensal microbiota can drive shifts in microbial composition and host response after antibiotic administration. As well as providing an explanation for variability in animal models using antibiotics, the findings encourage the development of personalized medication in antibiotic therapies. IMPORTANCE This work provides an understanding of variability in studies where

  19. Angiogenic and angiostatic factors in the molecular control of angiogenesis.

    Science.gov (United States)

    Distler, J H W; Hirth, A; Kurowska-Stolarska, M; Gay, R E; Gay, S; Distler, O

    2003-09-01

    The vascular system that ensures an adequate blood flow is required to provide the cells with sufficient supply of nutrients and oxygen. Two different mechanisms of the formation of new vessels can be distinguished: vasculogenesis, the formation of the first primitive vascular plexus de novo and angiogenesis, the formation of new vessels from preexisting ones. Both processes are regulated by a delicate balance of pro- and anti-angiogenic factors. Physiologically, angiostatic mediators outweigh the angiogenic molecules and angiogenesis does not occur. Under certain conditions such as tumor formation or wound healing, the positive regulators of angiogenesis predominate and the endothelium becomes activated. Angiogenesis is initiated by vasodilatation and an increased permeability. After destabilization of the vessel wall, endothelial cells proliferate, migrate and form a tube, which is finally stabilized by pericytes and smooth muscle cells. Numerous soluble growth factors and inhibitors, cytokines and proteases as well as extracellular matrix proteins and adhesion molecules strictly control this multi-step process. The properties and interactions of angiogenic molecules such as VEGFs, FGFs, angiopoietins, PDGF, angiogenin, angiotropin, HGF, CXC chemokines with ELR motif, PECAM-1, integrins and VE-cadherin as well as angiostatic key players such as angiostatin, endostatin, thrombospondin, CXC chemokines without ELR motif, PEDF are discussed in this review with respect to their molecular impact on angiogenesis.

  20. Transcription factor PIF4 controls the thermosensory activation of flowering

    KAUST Repository

    Kumar, S. Vinod; Lucyshyn, Doris; Jaeger, Katja E.; Aló s, Enriqueta; Alvey, Elizabeth; Harberd, Nicholas P.; Wigge, Philip A.

    2012-01-01

    Plant growth and development are strongly affected by small differences in temperature. Current climate change has already altered global plant phenology and distribution, and projected increases in temperature pose a significant challenge to agriculture. Despite the important role of temperature on plant development, the underlying pathways are unknown. It has previously been shown that thermal acceleration of flowering is dependent on the florigen, FLOWERING LOCUS T (FT). How this occurs is, however, not understood, because the major pathway known to upregulate FT, the photoperiod pathway, is not required for thermal acceleration of flowering. Here we demonstrate a direct mechanism by which increasing temperature causes the bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) to activate FT. Our findings provide a new understanding of how plants control their timing of reproduction in response to temperature. Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change. © 2012 Macmillan Publishers Limited. All rights reserved.

  1. Transcription factor PIF4 controls the thermosensory activation of flowering

    KAUST Repository

    Kumar, S. Vinod

    2012-03-21

    Plant growth and development are strongly affected by small differences in temperature. Current climate change has already altered global plant phenology and distribution, and projected increases in temperature pose a significant challenge to agriculture. Despite the important role of temperature on plant development, the underlying pathways are unknown. It has previously been shown that thermal acceleration of flowering is dependent on the florigen, FLOWERING LOCUS T (FT). How this occurs is, however, not understood, because the major pathway known to upregulate FT, the photoperiod pathway, is not required for thermal acceleration of flowering. Here we demonstrate a direct mechanism by which increasing temperature causes the bHLH transcription factor PHYTOCHROME INTERACTING FACTOR4 (PIF4) to activate FT. Our findings provide a new understanding of how plants control their timing of reproduction in response to temperature. Flowering time is an important trait in crops as well as affecting the life cycles of pollinator species. A molecular understanding of how temperature affects flowering will be important for mitigating the effects of climate change. © 2012 Macmillan Publishers Limited. All rights reserved.

  2. Krüppel-like factors: Three fingers in control

    Directory of Open Access Journals (Sweden)

    Swamynathan Shivalingappa K

    2010-04-01

    Full Text Available Abstract Krüppel-like factors (KLFs, members of the zinc-finger family of transcription factors capable of binding GC-rich sequences, have emerged as critical regulators of important functions all over the body. They are characterised by a highly conserved C-terminal DNA-binding motif containing three C2H2 zinc-finger domains, with variable N-terminal regulatory domains. Currently, there are 17 KLFs annotated in the human genome. In spite of their structural similarity to one another, the genes encoding different KLFs are scattered all over the genome. By virtue of their ability to activate and/or repress the expression of a large number of genes, KLFs regulate a diverse array of developmental events and cellular processes, such as erythropoiesis, cardiac remodelling, adipogenesis, maintenance of stem cells, epithelial barrier formation, control of cell proliferation and neoplasia, flow-mediated endothelial gene expression, skeletal and smooth muscle development, gluconeogenesis, monocyte activation, intestinal and conjunctival goblet cell development, retinal neuronal regeneration and neonatal lung development. Characteristic features, nomenclature, evolution and functional diversities of the human KLFs are reviewed here.

  3. Krüppel-like factors: three fingers in control.

    Science.gov (United States)

    Swamynathan, Shivalingappa K

    2010-04-01

    Krüppel-like factors (KLFs), members of the zinc-finger family of transcription factors capable of binding GC-rich sequences, have emerged as critical regulators of important functions all over the body. They are characterised by a highly conserved C-terminal DNA-binding motif containing three C2H2 zinc-finger domains, with variable N-terminal regulatory domains. Currently, there are 17 KLFs annotated in the human genome. In spite of their structural similarity to one another, the genes encoding different KLFs are scattered all over the genome. By virtue of their ability to activate and/or repress the expression of a large number of genes, KLFs regulate a diverse array of developmental events and cellular processes, such as erythropoiesis, cardiac remodelling, adipogenesis, maintenance of stem cells, epithelial barrier formation, control of cell proliferation and neoplasia, flow-mediated endothelial gene expression, skeletal and smooth muscle development, gluconeogenesis, monocyte activation, intestinal and conjunctival goblet cell development, retinal neuronal regeneration and neonatal lung development. Characteristic features, nomenclature, evolution and functional diversities of the human KLFs are reviewed here.

  4. Factors controlling nanoparticle pharmacokinetics: an integrated analysis and perspective.

    Science.gov (United States)

    Moghimi, S M; Hunter, A C; Andresen, T L

    2012-01-01

    Intravenously injected nanoparticulate drug carriers provide a wide range of unique opportunities for site-specific targeting of therapeutic agents to many areas within the vasculature and beyond. Pharmacokinetics and biodistribution of these carriers are controlled by a complex array of interrelated core and interfacial physicochemical and biological factors. Pertinent to realizing therapeutic goals, definitive maps that establish the interdependency of nanoparticle size, shape, and surface characteristics in relation to interfacial forces, biodistribution, controlled drug release, excretion, and adverse effects must be outlined. These concepts are critically evaluated and an integrated perspective is provided on the basis of the recent application of nanoscience approaches to nanocarrier design and engineering. The future of this exciting field is bright; some regulatory-approved products are already on the market and many are in late-phase clinical trials. With concomitant advances in extensive computational knowledge of the genomics and epigenomics of interindividual variations in drug responses, the boundaries toward development of personalized nanomedicines can be pushed further.

  5. Deciphering factors controlling groundwater arsenic spatial variability in Bangladesh

    Science.gov (United States)

    Tan, Z.; Yang, Q.; Zheng, C.; Zheng, Y.

    2017-12-01

    Elevated concentrations of geogenic arsenic in groundwater have been found in many countries to exceed 10 μg/L, the WHO's guideline value for drinking water. A common yet unexplained characteristic of groundwater arsenic spatial distribution is the extensive variability at various spatial scales. This study investigates factors influencing the spatial variability of groundwater arsenic in Bangladesh to improve the accuracy of models predicting arsenic exceedance rate spatially. A novel boosted regression tree method is used to establish a weak-learning ensemble model, which is compared to a linear model using a conventional stepwise logistic regression method. The boosted regression tree models offer the advantage of parametric interaction when big datasets are analyzed in comparison to the logistic regression. The point data set (n=3,538) of groundwater hydrochemistry with 19 parameters was obtained by the British Geological Survey in 2001. The spatial data sets of geological parameters (n=13) were from the Consortium for Spatial Information, Technical University of Denmark, University of East Anglia and the FAO, while the soil parameters (n=42) were from the Harmonized World Soil Database. The aforementioned parameters were regressed to categorical groundwater arsenic concentrations below or above three thresholds: 5 μg/L, 10 μg/L and 50 μg/L to identify respective controlling factors. Boosted regression tree method outperformed logistic regression methods in all three threshold levels in terms of accuracy, specificity and sensitivity, resulting in an improvement of spatial distribution map of probability of groundwater arsenic exceeding all three thresholds when compared to disjunctive-kriging interpolated spatial arsenic map using the same groundwater arsenic dataset. Boosted regression tree models also show that the most important controlling factors of groundwater arsenic distribution include groundwater iron content and well depth for all three

  6. Power factor improvement in three-phase networks with unbalanced inductive loads using the Roederstein ESTAmat RPR power factor controller

    Science.gov (United States)

    Diniş, C. M.; Cunţan, C. D.; Rob, R. O. S.; Popa, G. N.

    2018-01-01

    The paper presents the analysis of a power factor with capacitors banks, without series coils, used for improving power factor for a three-phase and single-phase inductive loads. In the experimental measurements, to improve the power factor, the Roederstein ESTAmat RPR power factor controller can command up to twelve capacitors banks, while experimenting using only six capacitors banks. Six delta capacitors banks with approximately equal reactive powers were used for experimentation. The experimental measurements were carried out with a three-phase power quality analyser which worked in three cases: a case without a controller with all capacitors banks permanently parallel connected with network, and two other cases with power factor controller (one with setting power factor at 0.92 and the other one at 1). When performing experiments with the power factor controller, a current transformer was used to measure the current on one phase (at a more charged or less loaded phase).

  7. Crystal structure of the tyrosine kinase domain of the hepatocyte growth factor receptor c-Met and its complex with the microbial alkaloid K-252a.

    Science.gov (United States)

    Schiering, Nikolaus; Knapp, Stefan; Marconi, Marina; Flocco, Maria M; Cui, Jean; Perego, Rita; Rusconi, Luisa; Cristiani, Cinzia

    2003-10-28

    The protooncogene c-met codes for the hepatocyte growth factor receptor tyrosine kinase. Binding of its ligand, hepatocyte growth factor/scatter factor, stimulates receptor autophosphorylation, which leads to pleiotropic downstream signaling events in epithelial cells, including cell growth, motility, and invasion. These events are mediated by interaction of cytoplasmic effectors, generally through Src homology 2 (SH2) domains, with two phosphotyrosine-containing sequence motifs in the unique C-terminal tail of c-Met (supersite). There is a strong link between aberrant c-Met activity and oncogenesis, which makes this kinase an important cancer drug target. The furanosylated indolocarbazole K-252a belongs to a family of microbial alkaloids that also includes staurosporine. It was recently shown to be a potent inhibitor of c-Met. Here we report the crystal structures of an unphosphorylated c-Met kinase domain harboring a human cancer mutation and its complex with K-252a at 1.8-A resolution. The structure follows the well established architecture of protein kinases. It adopts a unique, inhibitory conformation of the activation loop, a catalytically noncompetent orientation of helix alphaC, and reveals the complete C-terminal docking site. The first SH2-binding motif (1349YVHV) adopts an extended conformation, whereas the second motif (1356YVNV), a binding site for Grb2-SH2, folds as a type II Beta-turn. The intermediate portion of the supersite (1353NATY) assumes a type I Beta-turn conformation as in an Shc-phosphotyrosine binding domain peptide complex. K-252a is bound in the adenosine pocket with an analogous binding mode to those observed in previously reported structures of protein kinases in complex with staurosporine.

  8. Factors Controlling Nitrogen Fluxes in Groundwater in Agricultural Areas

    Science.gov (United States)

    Liao, L.; Green, C. T.; Bekins, B. A.; Bohlke, J. K.

    2010-12-01

    Predictions of effects of land use changes on water quality require identification of the relative importance of geochemical and hydrologic factors. To understand the factors controlling the transport of nitrogen in groundwater, vertical fluxes of water and solutes were estimated for 13 aquifers in agricultural areas located in California, Iowa, Maryland, Minnesota, Mississippi, Nebraska, North Carolina, Texas, and Wisconsin. The aquifers are overlain by unsaturated zones with thicknesses ranging from 2.5 to 100 m. Precipitation ranges from 19 to 132 cm/yr and irrigation ranges from 0 to 120 cm/yr. Main crop types include corn, soybeans, forage, wheat, and cotton. A 1-dimensional mathematical model was developed to estimate vertical N transport in response to N inputs on the land surface from chemical fertilizer, manure and atmospheric deposition. Simulated vertical profiles of O2, NO3-, N2 from denitrification, Cl- and atmospheric age tracers were matched to observations by adjusting parameters for recharge rate, unsaturated zone travel time, N leaching ratio (defined as leaching fraction of N reaching water table of N input at land surface), Cl- leaching ratio, O2 reduction rate and denitrification rate. Results indicated that vertical NO3 fluxes below the water table were affected by both geochemical and physical factors. High vertical NO3 fluxes below the water table are associated with high N input at the land surface. Values of Cl- leaching ratios were less than 1 (0.42 to 1) likely as a result of runoff and exported harvested crops. N leaching ratios were lower (0.1 to 0.6), consistent with additional N losses such as denitrification and volatilization. The sites with high leaching ratios for both N and Cl tended to be those with high recharge rates and low ET loss, defined as the fraction of applied water lost to ET. Modeled zero-order denitrification rates in the saturated zone varied within an order of magnitude with a maximum rate of 1.6 mg

  9. Does iron inhibit cryptoendolithic microbial communities?

    Science.gov (United States)

    Johnston, C. G.; Vestal, J. R.; Friedmann, E. I. (Principal Investigator)

    1988-01-01

    Photosynthetic activity of three cryptoendolithic microbial communities was studied under controlled conditions in the laboratory. In two of these communities, the dominant organisms were lichens, collected from Linnaeus Terrace and from Battleship Promontory. The third community, dominated by cyanobacteria, was collected from Battleship Promontory. Both sites are in the ice-free valleys of southern Victoria Land. Previous efforts have shown how physical conditions can influence metabolic activity in endolithic communities (Kappen and Friedmann 1983; Kappen, Friedmann, and Garty 1981; Vestal, Federle, and Friedmann 1984). Biological activity can also be strongly influenced by the chemical environment. Inorganic nutrients such as nitrate, ammonia, and phosphate are often limiting factors, so their effects on photosynthetic carbon-14 bicarbonate incorporation were investigated. Iron and manganese are two metals present in Linnaeus Terrace and Battleship Promontory sandstones, and their effects on photosynthesis were also studied. The results may add to our understanding of biogeochemical interactions within this unique microbial community.

  10. Pre- and postharvest preventive measures and intervention strategies to control microbial food safety hazards of fresh leafy vegetables.

    Science.gov (United States)

    Gil, Maria I; Selma, Maria V; Suslow, Trevor; Jacxsens, Liesbeth; Uyttendaele, Mieke; Allende, Ana

    2015-01-01

    This review includes an overview of the most important preventive measures along the farm to fork chain to prevent microbial contamination of leafy greens. It also includes the technological and managerial interventions related to primary production, postharvest handling, processing practices, distribution, and consumer handling to eliminate pathogens in leafy greens. When the microbiological risk is already present, preventive measures to limit actual contamination events or pathogen survival are considered intervention strategies. In codes of practice the focus is mainly put on explaining preventive measures. However, it is also important to establish more focused intervention strategies. This review is centered mainly on leafy vegetables as the commodity identified as the highest priority in terms of fresh produce microbial safety from a global perspective. There is no unique preventive measure or intervention strategy that could be applied at one point of the food chain. We should encourage growers of leafy greens to establish procedures based on the HACCP principles at the level of primary production. The traceability of leafy vegetables along the chain is an essential element in ensuring food safety. Thus, in dealing with the food safety issues associated with fresh produce it is clear that a multidisciplinary farm to fork strategy is required.

  11. Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases.

    Science.gov (United States)

    Welch, David; Buonanno, Manuela; Grilj, Veljko; Shuryak, Igor; Crickmore, Connor; Bigelow, Alan W; Randers-Pehrson, Gerhard; Johnson, Gary W; Brenner, David J

    2018-02-09

    Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic. By contrast, we have previously shown that far-UVC light (207-222 nm) efficiently inactivates bacteria without harm to exposed mammalian skin. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. We show for the first time that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm 2 of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Continuous very low dose-rate far-UVC light in indoor public locations is a promising, safe and inexpensive tool to reduce the spread of airborne-mediated microbial diseases.

  12. Microbial and environmental controls of methane fluxes along a soil moisture gradient in a Pacific coastal temperate rainforest

    DEFF Research Database (Denmark)

    Christiansen, Jesper Riis; Levy-Booth, David; Prescott, Cindy E.

    2016-01-01

    , and nutrient availability in three typical forest types across a soil moisture gradient. CH4 displayed a spatial variability changing from a net uptake in the upland soils (3.9–46 µmol CH4 m−2 h−1) to a net emission in the wetter soils (0–90 μmol CH4 m−2 h−1). Seasonal variations of CH4 fluxes were related......Most studies of greenhouse gas fluxes from forest soils in the coastal rainforest have considered carbon dioxide (CO2), whereas methane (CH4) has not received the same attention. Soil hydrology is a key driver of CH4 dynamics in ecosystems, but the impact on the function and distribution...... of the underlying microbial communities involved in CH4 cycling and the resultant net CH4 exchange is not well understood at this scale. We studied the growing season variations of in situ CH4 fluxes, microbial gene abundances of methanotrophs (CH4 oxidizers) and methanogens (CH4 producers), soil hydrology...

  13. Elimination of voltage reversal in multiple membrane electrode assembly installed microbial fuel cells (mMEA-MFCs) stacking system by resistor control.

    Science.gov (United States)

    Kim, Bongkyu; Chang, In Seop

    2018-08-01

    Voltage reversal (VR) in series connection of multiple membrane electrode assembly installed microbial fuel cells (mMEA-MFC) is eliminated by manipulating the resistor control. Discharge test results collected from two mMEA-MFCs initially operated (designated as P1 and P2) confirm that the performance of P2 exceeds that of P1. Thus, driving P1 and P2 as serially stacked MFCs generate the VR in P1. Controlling the inserted resistor adjust the current production of P2 to maintain balance with P1, and the VR in P1 is eliminated in the operation of stacking mode. Thus, manipulating the internal resistance provide an applicable approach to suppress VR in the stacking of mMEA-MFCs system. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Microbial xanthophylls.

    Science.gov (United States)

    Bhosale, Prakash; Bernstein, Paul S

    2005-09-01

    Xanthophylls are oxygenated carotenoids abundant in the human food supply. Lutein, zeaxanthin, and cryptoxanthin are major xanthophyll carotenoids in human plasma. The consumption of these xanthophylls is directly associated with reduction in the risk of cancers, cardiovascular disease, age-related macular degeneration, and cataract formation. Canthaxanthin and astaxanthin also have considerable importance in aquaculture for salmonid and crustacean pigmentation, and are of commercial interest for the pharmaceutical and food industries. Chemical synthesis is a major source for the heavy demand of xanthophylls in the consumer market; however, microbial producers also have potential as commercial sources. In this review, we discuss the biosynthesis, commercial utility, and major microbial sources of xanthophylls. We also present a critical review of current research and technologies involved in promoting microbes as potential commercial sources for mass production.

  15. Factors influencing ruminal bacterial community diversity and composition and microbial fibrolytic enzyme abundance in lactating dairy cows with a focus on the role of active dry yeast.

    Science.gov (United States)

    AlZahal, Ousama; Li, Fuyong; Guan, Le Luo; Walker, Nicola D; McBride, Brian W

    2017-06-01

    The objective of the current study was to employ a DNA-based sequencing technology to study the effect of active dry yeast (ADY) supplementation, diet type, and sample location within the rumen on rumen bacterial community diversity and composition, and to use an RNA-based method to study the effect of ADY supplementation on rumen microbial metabolism during high-grain feeding (HG). Our previous report demonstrated that the supplementation of lactating dairy cows with ADY attenuated the effect of subacute ruminal acidosis. Therefore, we used samples from that study, where 16 multiparous, rumen-cannulated lactating Holstein cows were randomly assigned to 1 of 2 dietary treatments: ADY (Saccharomyces cerevisiae strain Y1242, 80 billion cfu/animal per day) or control (carrier only). Cows received a high-forage diet (77:23, forage:concentrate), then were abruptly switched to HG (49:51, forage:concentrate). Rumen bacterial community diversity and structure were highly influenced by diet and sampling location (fluid, solids, epimural). The transition to HG reduced bacterial diversity, but epimural bacteria maintained a greater diversity than fluid and solids. Analysis of molecular variance indicated a significant separation due to diet × sampling location, but not due to treatment. Across all samples, the analysis yielded 6,254 nonsingleton operational taxonomic units (OTU), which were classified into several phyla: mainly Firmicutes, Bacteroidetes, Fibrobacteres, Tenericutes, and Proteobacteria. High forage and solids were dominated by OTU from Fibrobacter, whereas HG and fluid were dominated by OTU from Prevotella. Epimural samples, however, were dominated in part by Campylobacter. Active dry yeast had no effect on bacterial community diversity or structure. The phylum SR1 was more abundant in all ADY samples regardless of diet or sampling location. Furthermore, on HG, OTU2 and OTU3 (both classified into Fibrobacter succinogenes) were more abundant with ADY in fluid

  16. The Effects of Fungicide, Soil Fumigant, Bio-Organic Fertilizer and Their Combined Application on Chrysanthemum Fusarium Wilt Controlling, Soil Enzyme Activities and Microbial Properties

    Directory of Open Access Journals (Sweden)

    Shuang Zhao

    2016-04-01

    Full Text Available Sustained monoculture often leads to a decline in soil quality, in particular to the build-up of pathogen populations, a problem that is conventionally addressed by the use of either fungicide and/or soil fumigation. This practice is no longer considered to be either environmentally sustainable or safe. While the application of organic fertilizer is seen as a means of combating declining soil fertility, it has also been suggested as providing some control over certain soil-borne plant pathogens. Here, a greenhouse comparison was made of the Fusarium wilt control efficacy of various treatments given to a soil in which chrysanthemum had been produced continuously for many years. The treatments comprised the fungicide carbendazim (MBC, the soil fumigant dazomet (DAZ, the incorporation of a Paenibacillus polymyxa SQR21 (P. polymyxa SQR21, fungal antagonist enhanced bio-organic fertilizer (BOF, and applications of BOF combined with either MBC or DAZ. Data suggest that all the treatments evaluated show good control over Fusarium wilt. The MBC and DAZ treatments were effective in suppressing the disease, but led to significant decrease in urease activity and no enhancement of catalase activity in the rhizosphere soils. BOF including treatments showed significant enhancement in soil enzyme activities and microbial communities compared to the MBC and DAZ, evidenced by differences in bacterial/fungi (B/F ratios, Shannon–Wiener indexes and urease, catalase and sucrase activities in the rhizosphere soil of chrysanthemum. Of all the treatments evaluated, DAZ/BOF application not only greatly suppressed Fusarium wilt and enhanced soil enzyme activities and microbial communities but also promoted the quality of chrysanthemum obviously. Our findings suggest that combined BOF with DAZ could more effectively control Fusarium wilt disease of chrysanthemum.

  17. Design of automatic power factor control system | Yanev | Botswana ...

    African Journals Online (AJOL)

    Maintenance of the proper power factor is a very important matter for the industry and for the economy of any country. A study of the power factor values for a number of industrial plants in Botswana shows that they operate at power-factors lower than the optimal values. If a plant power factor is different from its optimal value, ...

  18. Factors controlling high-frequency radiation from extended ruptures

    Science.gov (United States)

    Beresnev, Igor A.

    2017-09-01

    Small-scale slip heterogeneity or variations in rupture velocity on the fault plane are often invoked to explain the high-frequency radiation from earthquakes. This view has no theoretical basis, which follows, for example, from the representation integral of elasticity, an exact solution for the radiated wave field. The Fourier transform, applied to the integral, shows that the seismic spectrum is fully controlled by that of the source time function, while the distribution of final slip and rupture acceleration/deceleration only contribute to directivity. This inference is corroborated by the precise numerical computation of the full radiated field from the representation integral. We compare calculated radiation from four finite-fault models: (1) uniform slip function with low slip velocity, (2) slip function spatially modulated by a sinusoidal function, (3) slip function spatially modulated by a sinusoidal function with random roughness added, and (4) uniform slip function with high slip velocity. The addition of "asperities," both regular and irregular, does not cause any systematic increase in the spectral level of high-frequency radiation, except for the creation of maxima due to constructive interference. On the other hand, an increase in the maximum rate of slip on the fault leads to highly amplified high frequencies, in accordance with the prediction on the basis of a simple point-source treatment of the fault. Hence, computations show that the temporal rate of slip, not the spatial heterogeneity on faults, is the predominant factor forming the high-frequency radiation and thus controlling the velocity and acceleration of the resulting ground motions.

  19. Role of quorum sensing by Pseudomonas aeruginosa in microbial keratitis and cystic fibrosis

    DEFF Research Database (Denmark)

    Willcox, M.D.P.; Zhu, H.; Conibear, T.C.R.

    2008-01-01

    to control the expression of many virulence factors is the N-acylated homoserine lactone (AHL) regulatory system. Hence, there is considerable interest in targeting this regulatory pathway to develop novel therapeutics for infection control. P. aeruginosa is the principal cause of microbial keratitis...

  20. Control of trichome branching by Chromatin Assembly Factor-1

    Directory of Open Access Journals (Sweden)

    Hennig Lars

    2008-05-01

    Full Text Available Abstract Background Chromatin dynamics and stability are both required to control normal development of multicellular organisms. Chromatin assembly factor CAF-1 is a histone chaperone that facilitates chromatin formation and the maintenance of specific chromatin states. In plants and animals CAF-1 is essential for normal development, but it is poorly understood which developmental pathways require CAF-1 function. Results Mutations in all three CAF-1 subunits affect Arabidopsis trichome morphology and lack of CAF-1 function results in formation of trichomes with supernumerary branches. This phenotype can be partially alleviated by external sucrose. In contrast, other aspects of the CAF-1 mutant phenotype, such as defective meristem function and organ formation, are aggravated by external sucrose. Double mutant analyses revealed epistatic interactions between CAF-1 mutants and stichel, but non-epistatic interactions between CAF-1 mutants and glabra3 and kaktus. In addition, mutations in CAF-1 could partly suppress the strong overbranching and polyploidization phenotype of kaktus mutants. Conclusion CAF-1 is required for cell differentiation and regulates trichome development together with STICHEL in an endoreduplication-independent pathway. This function of CAF-1 can be partially substituted by application of exogenous sucrose. Finally, CAF-1 is also needed for the high degree of endoreduplication in kaktus mutants and thus for the realization of kaktus' extreme overbranching phenotype.

  1. Factors controlling crystallization of miserite glass-ceramic.

    Science.gov (United States)

    Muhammed, Fenik K; Moorehead, Robert; van Noort, Richard; Pollington, Sarah

    2015-12-01

    The purpose of this study was to investigate a range of variables affecting the synthesis of a miserite glass-ceramic (GC). Miserite glass was synthesized by the melt quench technique. The crystallization kinetics of the glass were determined using Differential Thermal Analysis (DTA). The glasses were ground with dry ball-milling and then sieved to different particle sizes prior to sintering. These particle sizes were submitted to heat treatment regimes in a high temperature furnace to form the GC. The crystal phases of the GC were analyzed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to examine the microstructure of the cerammed glass. XRD analysis confirmed that the predominant crystalline phase of the GC was miserite along with a minor crystalline phase of cristobalite only when the particle size is <20 μm and the heat treatment at 1000°C was carried out for 4h and slowly cooled at the furnace rate. For larger particle sizes and faster cooling rates, a pseudowollastonite crystalline phase was produced. Short sintering times produced either a pseudowollastonite or xonotolite crystalline phase. The current study has shown that particle size and heat treatment schedules are major factors in controlling the synthesis of miserite GC. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  2. Factors controlling pathogen destruction during anaerobic digestion of biowastes

    International Nuclear Information System (INIS)

    Smith, S.R.; Lang, N.L.; Cheung, K.H.M.; Spanoudaki, K.

    2005-01-01

    Anaerobic digestion is the principal method of stabilising biosolids from urban wastewater treatment in the UK, and it also has application for the treatment of other types of biowaste. Increasing awareness of the potential risks to human and animal health from environmental sources of pathogens has focused attention on the efficacy of waste treatment processes at destroying pathogenic microorganisms in biowastes recycled to agricultural land. The degree of disinfection achieved by a particular anaerobic digester is influenced by a variety of interacting operational variables and conditions, which can often deviate from the ideal. Experimental investigations demonstrate that Escherichia coli and Salmonella spp. are not damaged by mesophilic temperatures, whereas rapid inactivation occurs by thermophilic digestion. A hydraulic, biokinetic and thermodynamic model of pathogen inactivation during anaerobic digestion showed that a 2 log 10 reduction in E. coli (the minimum removal required for agricultural use of conventionally treated biosolids) is likely to challenge most conventional mesophilic digesters, unless strict maintenance and management practices are adopted to minimise dead zones and by-pass flow. Efficient mixing and organic matter stabilisation are the main factors controlling the rate of inactivation under mesophilic conditions and not a direct effect of temperature per se on pathogenic organisms

  3. 76 FR 35130 - Pipeline Safety: Control Room Management/Human Factors

    Science.gov (United States)

    2011-06-16

    ...: Control Room Management/Human Factors AGENCY: Pipeline and Hazardous Materials Safety Administration... the Control Room Management/Human Factors regulations in order to realize the safety benefits sooner... FR 5536). By this amendment to the Control Room Management/Human Factors (CRM) rule, an operator must...

  4. Human factors measurement for future air traffic control systems.

    Science.gov (United States)

    Langan-Fox, Janice; Sankey, Michael J; Canty, James M

    2009-10-01

    This article provides a critical review of research pertaining to the measurement of human factors (HF) issues in current and future air traffic control (ATC). Growing worldwide air traffic demands call for a radical departure from current ATC systems. Future systems will have a fundamental impact on the roles and responsibilities of ATC officers (ATCOs). Valid and reliable methods of assessing HF issues associated with these changes, such as a potential increase (or decrease) in workload, are of utmost importance for advancing theory and for designing systems, procedures, and training. We outline major aviation changes and how these relate to five key HF issues in ATC. Measures are outlined, compared, and evaluated and are followed by guidelines for assessing these issues in the ATC domain. Recommendations for future research are presented. A review of the literature suggests that situational awareness and workload have been widely researched and assessed using a variety of measures, but researchers have neglected the areas of trust, stress, and boredom. We make recommendations for use of particular measures and the construction of new measures. It is predicted that, given the changing role of ATCOs and profound future airspace requirements and configurations, issues of stress, trust, and boredom will become more significant. Researchers should develop and/or refine existing measures of all five key HF issues to assess their impact on ATCO performance. Furthermore, these issues should be considered in a holistic manner. The current article provides an evaluation of research and measures used in HF research on ATC that will aid research and ATC measurement.

  5. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

    Microbial polyhydroxyalkanoates (PHAs), one of the largest groups of thermoplastic polyesters are receiving much attention as biodegradable substitutes for non-degradable plastics. Poly(D-3-hydroxybutyrate) (PHB) is the most ubiquitous and most intensively studied PHA. Microorganisms degrading these polyesters are widely distributed in various environments. Although various PHB-degrading microorganisms and PHB depolymerases have been studied and characterized, there are still many groups of microorganisms and enzymes with varying properties awaiting various applications. Distributions of PHB-degrading microorganisms, factors affecting the biodegradability of PHB, and microbial and enzymatic degradation of PHB are discussed in this review. We also propose an application of a new isolated, thermophilic PHB-degrading microorganism, Streptomyces strain MG, for producing pure monomers of PHA and useful chemicals, including D-3-hydroxycarboxylic acids such as D-3-hydroxybutyric acid, by enzymatic degradation of PHB.

  6. What factors control the size of an eruption?

    Science.gov (United States)

    Gudmundsson, Agust

    2017-04-01

    pressure so as to drive out magma for a much longer time during an eruption than is otherwise possible. As a consequence a much higher proportion of the magma in the chamber is driven or squeezed out during an eruption associated with caldera or graben subsidence than is possible during an ordinary poroelastic chamber behaviour. It follows that the volume of eruptive materials may approach the total volume of the chamber resulting in a large eruption. Here a large eruption is thus the consequence—not the cause—of the subsidence of the caldera/graben block. Thus, once the factors controlling large-scale subsidence of a caldera/graben block are established during a particular unrest/rifting episode, primarily using geodetic and seismic data, the probability of a large eruption can be assessed and used for reliable forecasting. Gudmundsson, A., 2015. Collapse-driven large eruptions. Journal of Volcanology and Geothermal Research, 304, 1-10. Gudmundsson, A., 2016. The mechanics of large volcanic eruptions. Earth-Science Reviews, 163, 72-93.

  7. Medium factors on anaerobic production of rhamnolipids by Pseudomonas aeruginosa SG and a simplifying medium for in situ microbial enhanced oil recovery applications.

    Science.gov (United States)

    Zhao, Feng; Zhou, Jidong; Han, Siqin; Ma, Fang; Zhang, Ying; Zhang, Jie

    2016-04-01

    Aerobic production of rhamnolipid by Pseudomonas aeruginosa was extensively studied. But effect of medium composition on anaerobic production of rhamnolipid by P. aeruginosa was unknown. A simplifying medium facilitating anaerobic production of rhamnolipid is urgently needed for in situ microbial enhanced oil recovery (MEOR). Medium factors affecting anaerobic production of rhamnolipid were investigated using P. aeruginosa SG (Genbank accession number KJ995745). Medium composition for anaerobic production of rhamnolipid by P. aeruginosa is different from that for aerobic production of rhamnolipid. Both hydrophobic substrate and organic nitrogen inhibited rhamnolipid production under anaerobic conditions. Glycerol and nitrate were the best carbon and nitrogen source. The commonly used N limitation under aerobic conditions was not conducive to rhamnolipid production under anaerobic conditions because the initial cell growth demanded enough nitrate for anaerobic respiration. But rhamnolipid was also fast accumulated under nitrogen starvation conditions. Sufficient phosphate was needed for anaerobic production of rhamnolipid. SO4(2-) and Mg(2+) are required for anaerobic production of rhamnolipid. Results will contribute to isolation bacteria strains which can anaerobically produce rhamnolipid and medium optimization for anaerobic production of rhamnolipid. Based on medium optimization by response surface methodology and ions composition of reservoir formation water, a simplifying medium containing 70.3 g/l glycerol, 5.25 g/l NaNO3, 5.49 g/l KH2PO4, 6.9 g/l K2HPO4·3H2O and 0.40 g/l MgSO4 was designed. Using the simplifying medium, 630 mg/l of rhamnolipid was produced by SG, and the anaerobic culture emulsified crude oil to EI24 = 82.5 %. The simplifying medium was promising for in situ MEOR applications.

  8. Control to goal of cardiometabolic risk factors among Nigerians ...

    African Journals Online (AJOL)

    2011-07-12

    Jul 12, 2011 ... Therapeutic goals used to define risk or poor control were values adopted by expert groups such as ... medical wards in urban healthcare centers showed that .... *Status of control was based on the mean observed value.

  9. COMPLIANCE AS FACTORING BUSINESS RISK MANAGEMENT: CONTROL ASPECTS

    OpenAIRE

    V.K. Makarovych

    2016-01-01

    Indetermination of modern economy conditions and the lack of theoretical knowledge gained by domestic scientists about risk in factoring business actualize the research concerning the methodology and technique of factoring companies’ risk management. The article examines compliance which is the technology innovative for Ukrainian market of factoring risk management technologies. It is determined that the compliance is the risk management process directed to free will correspondence to sta...

  10. Lifestyle factors and reproductive health: taking control of your fertility

    OpenAIRE

    Sharma, Rakesh; Biedenharn, Kelly R; Fedor, Jennifer M; Agarwal, Ashok

    2013-01-01

    Approximately 10 to 15% of couples are impacted by infertility. Recently, the pivotal role that lifestyle factors play in the development of infertility has generated a considerable amount of interest. Lifestyle factors are the modifiable habits and ways of life that can greatly influence overall health and well-being, including fertility. Many lifestyle factors such as the age at which to start a family, nutrition, weight, exercise, psychological stress, environmental and occupational exposu...

  11. Simultaneous water desalination and electricity generation in a microbial desalination cell with electrolyte recirculation for pH control

    KAUST Repository

    Qu, Youpeng

    2012-02-01

    A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m 2 with a 50mM phosphate buffer solution (PBS) and 776±30mW/m 2 with 25mM PBS. These power densities were higher than those obtained without recirculation of 698±10mW/m 2 (50mM PBS) and 508±11mW/m 2 (25mM PBS). The salt solution (20g/L NaCl) was reduced in salinity by 34±1% (50mM) and 37±2% (25mM) with recirculation (rMDC), and by 39±1% (50mM) and 25±3% (25mM) without recirculation (MDC). These results show that electrolyte recirculation using an rMDC is an effective method to increase power and achieve efficient desalination by eliminating pH imbalances. © 2011 Elsevier Ltd.

  12. CubeSat Form Factor Thermal Control Louvers

    Science.gov (United States)

    Evans, Allison L. (Inventor)

    2018-01-01

    Thermal control louvers for CubeSats or small spacecraft may include a plurality of springs attached to a back panel of the thermal control louvers. The thermal control louvers may also include a front panel, which includes at least two end panels interlocked with one or more middle panels. The front panel may secure the springs, shafts, and flaps to the back panel.

  13. From lithotroph- to organotroph-dominant: directional shift of microbial community in sulphidic tailings during phytostabilization

    Science.gov (United States)

    Li, Xiaofang; Bond, Philip L.; Van Nostrand, Joy D.; Zhou, Jizhong; Huang, Longbin

    2015-01-01

    Engineering microbial diversity to enhance soil functions may improve the success of direct revegetation in sulphidic mine tailings. Therefore, it is essential to explore how remediation and initial plant establishment can alter microbial communities, and, which edaphic factors control these changes under field conditions. A long-term revegetation trial was established at a Pb-Zn-Cu tailings impoundment in northwest Queensland. The control and amended and/or revegetated treatments were sampled from the 3-year-old trial. In total, 24 samples were examined using pyrosequencing of 16S rRNA genes and various chemical properties. The results showed that the microbial diversity was positively controlled by soil soluble Si and negatively controlled by soluble S, total Fe and total As, implying that pyrite weathering posed a substantial stress on microbial development in the tailings. All treatments were dominated by typical extremophiles and lithotrophs, typically Truepera, Thiobacillus, Rubrobacter; significant increases in microbial diversity, biomass and frequency of organotrophic genera (typically Nocardioides and Altererythrobacter) were detected in the revegetated and amended treatment. We concluded that appropriate phytostabilization options have the potential to drive the microbial diversity and community structure in the tailings toward those of natural soils, however, inherent environmental stressors may limit such changes. PMID:26268667

  14. Key Factors Controlling the Growth of Biological Soil Crusts: Towards a Protocol to Produce Biocrusts in Greenhouse Facilities

    Science.gov (United States)

    Velasco Ayuso, Sergio; María Giraldo Silva, Ana; Nelson, Corey; Barger, Nichole; Antoninka, Anita; Bowker, Matthew; Garcia-Pichel, Ferran

    2016-04-01

    Biological soil crusts (= biocrusts) are topsoil communities comprise of, but not limited to, cyanobacteria, algae, lichens, and mosses that grow intimately associated with soil particles in drylands. Biocrusts have central ecological roles in these areas as sources of carbon and nutrients, and efficiently retain water and prevent soil erosion, which improves soil structure and promotes soil fertility. However, human activities, such as cattle grazing, hiking or military training, are rapidly striking biocrusts. Although it is well known that the inoculation with cyanobacteria or lichens can enhance the recovery of biocrusts in degraded soils, little is known about the factors that control their growth rates. Using soil and inocula from four different sites located in one cold desert (Utah) and in one hot desert (New Mexico), we performed a fractional factorial experiment involving seven factors (water, light, P, N, calcium carbonate, trace metals and type of inoculum) to screen their effects on the growth of biocrusts. After four months, we measured the concentration of chlorophyll a, and we discovered that water, light and P, N or P+N were the most important factors controlling the growth of biocrusts. In the experimental treatments involving these three factors we measured a similar concentration of chlorophyll a (or even higher) to this found in the field locations. Amplification of the 16S rRNA gene segment using universal bacteria primers revealed a microbial community composition in the biocrusts grown that closely corresponds to initial measurements made on inocula. In summary, based on our success in obtaining biocrust biomass from natural communities in greenhouse facilities, without significantly changing its community composition at the phylum and cyanobacterial level, we are paving the road to propose a protocol to produce a high quality-nursed inoculum aiming to assist restoration of arid and semi-arid ecosystems affected by large-scale disturbances.

  15. Factors controlling the initiation of Snowball Earth events

    Science.gov (United States)

    Voigt, A.

    2012-12-01

    During the Neoproterozoic glaciations tropical continents were covered by active glaciers that extended down to sea level. To explain these glaciers, the Snowball Earth hypothesis assumes that oceans were completely sea-ice covered during these glaciation, but there is an ongoing debate whether or not some regions of the tropical oceans remained open. In this talk, I will describe past and ongoing climate modelling activities with the comprehensive coupled climate model ECHAM5/MPI-OM that identify and compare factors that control the initiation of Snowball Earth events. I first show that shifting the continents from their present-day location to their Marinoan (635 My BP) low-latitude location increases the planetary albedo, cools the climate, and thereby allows Snowball Earth initiation at higher levels of total solar irradiance and atmospheric CO2. I then present simulations with successively lowered bare sea-ice albedo, disabled sea-ice dynamics, and switched-off ocean heat transport. These simulations show that both lowering the bare sea-ice albedo and disabling sea-ice dynamics increase the critical sea-ice cover in ECHAM5/MPI-OM, but sea-ice dynamics due to strong equatorward sea-ice transport have a much larger influence on the critical CO2. Disabling sea-ice transport allows a state with sea-ice margin at 10 deg latitude by virtue of the Jormungand mechanism. The accumulation of snow on land, in combination with tropical land temperatures below or close to freezing, suggests that tropical land glaciers could easily form in such a state. However, in contrast to aquaplanet simulations without ocean heat transport, there is no sign of a Jormungand hysteresis in the coupled simulations. Ocean heat transport is not responsible for the lack of a Jormungand hysteresis in the coupled simulations. By relating the above findings to previous studies, I will outline promising future avenues of research on the initiation of Snowball Earth events. In particular, an

  16. Investigating the effective factors on management internal controls applying

    Directory of Open Access Journals (Sweden)

    Ahmad Ahmadkhani

    2012-08-01

    Full Text Available Information technology plays an important role on increasing internal control in many organizations. In this paper, we present an empirical study to measure the impact of information technology, hiring high quality skilled management team, using high quality standards and increasing employees' awareness on managing internal control. The survey uses a questionnaire based on Likert scale and distributes among the people who work in either administration or financial sectors of governmental agencies in province of Zanjan, Iran. The results of the study indicate that the implementation of information technology positively influences management team to control their system, more effectively, using more skilled and specialized managers positively influences management internal control, an organization with suitable standard positively influences management internal control and increasing employees' awareness positively influences management internal control.

  17. Lifestyle factors and reproductive health: taking control of your fertility.

    Science.gov (United States)

    Sharma, Rakesh; Biedenharn, Kelly R; Fedor, Jennifer M; Agarwal, Ashok

    2013-07-16

    Approximately 10 to 15% of couples are impacted by infertility. Recently, the pivotal role that lifestyle factors play in the development of infertility has generated a considerable amount of interest. Lifestyle factors are the modifiable habits and ways of life that can greatly influence overall health and well-being, including fertility. Many lifestyle factors such as the age at which to start a family, nutrition, weight, exercise, psychological stress, environmental and occupational exposures, and others can have substantial effects on fertility; lifestyle factors such as cigarette smoking, illicit drug use, and alcohol and caffeine consumption can negatively influence fertility while others such as preventative care may be beneficial. The present literature review encompasses multiple lifestyle factors and places infertility in context for the couple by focusing on both males and females; it aims to identify the roles that lifestyle factors play in determining reproductive status. The growing interest and amount of research in this field have made it evident that lifestyle factors have a significant impact on fertility.

  18. Forest canopy structural controls over throughfall affect soil microbial community structure in an epiphyte-laden maritime oak stand

    Science.gov (United States)

    Van Stan, J. T., II; Rosier, C. L.; Schrom, J. O.; Wu, T.; Reichard, J. S.; Kan, J.

    2014-12-01

    Identifying spatiotemporal influences on soil microbial community (SMC) structure is critical to understanding of patterns in nutrient cycling and related ecological services. Since forest canopy structure alters the spatiotemporal patterning of precipitation water and solute supplies to soils (via the "throughfall" mechanism), is it possible changes in SMC structure variability could arise from modifications in canopy elements? Our study investigates this question by monitoring throughfall water and dissolved ion supply to soils beneath a continuum of canopy structure: from a large gap (0% cover) to heavy Tillandsia usneoides L. (Spanish moss) canopy (>90% cover). Throughfall water supply diminished with increasing canopy cover, yet increased washoff/leaching of Na+, Cl-, PO43-, and SO42- from the canopy to the soils (p < 0.01). Presence of T. usneoides diminished throughfall NO3-, but enhanced NH4+, concentrations supplied to subcanopy soils. The mineral soil horizon (0-10 cm) from canopy gaps, bare canopy, and T. usneoides-laden canopy significantly differed (p < 0.05) in soil chemistry parameters (pH, Ca2+, Mg2+, CEC). PCR-DGGE banding patterns beneath similar canopy covers (experiencing similar throughfall dynamics) also produced high similarities per ANalyses Of SIMilarity (ANO-SIM), and clustered together when analyzed by Nonmetric Multidimensional Scaling (NMDS). Correlation analysis of DGGE banding patterns, throughfall dynamics, and soil chemistry yielded significant correlations (p < 0.05) between fungal communities and soil chemical properties significantly differing between canopy cover types (pH: r2 = 0.50; H+ %-base saturation: r2 = 0.48; Ca2+ %-base saturation: r2 = 0.43). Bacterial community structure correlated with throughfall NO3-, NH4+, and Ca2+ concentrations (r2 = 0.37, p = 0.16). These results suggest that modifications of forest canopy structures are capable of affecting mineral-soil horizon SMC structure via the throughfall mechanism when

  19. Factors controlling floc settling velocity along a longitudinal estuarine transect

    Science.gov (United States)

    Manning, A.J.; Schoellhamer, D.H.

    2013-01-01

    A 147 km longitudinal transect of flocculated cohesive sediment properties in San Francisco Bay (SFB) was conducted on June 17th, 2008. Our aim was to determine the factors that control floc settling velocity along the longitudinal axis of the estuary. The INSSEV-LF video system was used to measure floc diameters and settling velocities at 30 stations at a distance of 0.7 m above the estuary bed. Floc sizes (D) ranged from 22 μm to 639 μm and settling velocities (Ws) ranged between 0.04 mm·s− 1 and 15.8 mm·s− 1 during the longitudinal transect. Nearbed turbulent shear stresses throughout the transect duration were within the 0.2–0.5 Pa range which typically stimulates flocculation growth. The individual D–Ws–floc density plots suggest the suspended sediments encountered throughout SFB were composed of both muddy cohesive sediment and mixed sediments flocs. Mass-weighted population mean settling velocity (Wsmass) ranged from 0.5 mm·s− 1 to 10 mm·s− 1. The macrofloc and microfloc (demarcation at 160 μm) sub-populations demonstrated parameterised settling velocities which spanned nearly double the range of the sample mean settling velocities (Wsmean). The macroflocs tended to dominate the suspended mass (up to 77% of the ambient suspended solid concentration; SSC) from San Pablo Bay to Carquinez Strait (the vicinity of the turbidity maximum zone). Microfloc mass was particularly significant (typically 60–100% of the SSC) in the northern section of South Bay and most of Central Bay. The transect took eleven hours to complete and was not fully synoptic. During slack tide, larger and faster settling flocs deposited, accounting for most of the longitudinal variability. The best single predictor of settling velocity was water velocity 39 min prior to sampling, not suspended-sediment concentration or salinity. Resuspension and settling lags are likely responsible for the lagged response of settling velocity to water velocity. The distribution of

  20. Long-term monitoring of waterborne pathogens and microbial source tracking markers in paired agricultural watersheds under controlled and conventional tile drainage management.

    Science.gov (United States)

    Wilkes, Graham; Brassard, Julie; Edge, Thomas A; Gannon, Victor; Gottschall, Natalie; Jokinen, Cassandra C; Jones, Tineke H; Khan, Izhar U H; Marti, Romain; Sunohara, Mark D; Topp, Edward; Lapen, David R

    2014-06-01

    Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P = 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tile-drained fields to stream could be reduced by CTD utilization. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  1. Integrated effect of microbial antagonist, organic amendment and fungicide in controlling seedling mortality (Rhizoctonia solani) and improving yield in pea (Pisum sativum L.).

    Science.gov (United States)

    Akhter, Wasira; Bhuiyan, Mohamed Khurshed Alam; Sultana, Farjana; Hossain, Mohamed Motaher

    2015-01-01

    The study evaluated the comparative performance of a few microbial antagonists, organic amendments and fungicides and their integration for the management of seedling mortality (Rhizoctonia solani Kühn) and yield improvement in pea (Pisum sativum L.). Before setting the experiment in field microplots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of R. solani, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic organic amendment and an appropriate fungicide. A greenhouse pathogenicity test compared differences in seedling mortality in pea inoculated by four isolates of R. solani and identified the isolate RS10 as the most virulent one. Among the 20 isolates screened in dual culture assay on PDA, T. harzianum isolate T-3 was found to show the highest (77.22%) inhibition of the radial growth of R. solani. A complete inhibition (100.00%) of colony growth of R. solani was observed when fungicide Bavistin 50 WP and Provax-200 at the rate of 100 and 250 ppm, respectively, were used, while Provax-200 was found to be highly compatible with T. harzianum. Mustard oilcake gave maximum inhibition (60.28%) of the radial growth of R. solani at all ratios, followed by sesame oilcake and tea waste. Integration of soil treatment with T. harzianum isolate T-3 and mustard oilcake and seed treatment with Provax-200 appeared to be significantly superior in reducing seedling mortality and improving seed yield in pea in comparison to any single or dual application of them in the experimental field. The research results will help growers develop integrated disease management strategies for the control of Rhizoctonia disease in pea. The research results show the need for an integrating selective microbial antagonist, organic amendment and fungicide to achieve appropriate management of seedling mortality (R. solani) and increase of seed yield in pea. Copyright © 2014 Académie des sciences. Published by Elsevier SAS. All

  2. Long-Term Monitoring of Waterborne Pathogens and Microbial Source Tracking Markers in Paired Agricultural Watersheds under Controlled and Conventional Tile Drainage Management

    Science.gov (United States)

    Wilkes, Graham; Brassard, Julie; Edge, Thomas A.; Gannon, Victor; Gottschall, Natalie; Jokinen, Cassandra C.; Jones, Tineke H.; Khan, Izhar U. H.; Marti, Romain; Sunohara, Mark D.; Topp, Edward

    2014-01-01

    Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P = 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tile-drained fields to stream could be reduced by CTD utilization. PMID:24727274

  3. QMRA (quantitative microbial risk assessment) and HACCP (hazard analysis and critical control points) for management of pathogens in wastewater and sewage sludge treatment and reuse.

    Science.gov (United States)

    Westrell, T; Schönning, C; Stenström, T A; Ashbolt, N J

    2004-01-01

    Hazard Analysis and Critical Control Points (HACCP) was applied for identifying and controlling exposure to pathogenic microorganisms encountered during normal sludge and wastewater handling at a 12,500 m3/d treatment plant utilising tertiary wastewater treatment and mesophilic sludge digestion. The hazardous scenarios considered were human exposure during treatment, handling, soil application and crop consumption, and exposure via water at the wetland-area and recreational swimming. A quantitative microbial risk assessment (QMRA), including rotavirus, adenovirus, haemorrhagic E. coli, Salmonella, Giardia and Cryptosporidium, was performed in order to prioritise pathogen hazards for control purposes. Human exposures were treated as individual risks but also related to the endemic situation in the general population. The highest individual health risk from a single exposure was via aerosols for workers at the belt press for sludge dewatering (virus infection risk = 1). The largest impact on the community would arise if children ingested sludge at the unprotected storage site, although in the worst-case situation the largest number of infections would arise through vegetables fertilised with sludge and eaten raw (not allowed in Sweden). Acceptable risk for various hazardous scenarios, treatment and/or reuse strategies could be tested in the model.

  4. Microbial properties of soil aggregates created by earthworms and other factors: spherical and prismatic soil aggregates from unreclaimed post-mining sites

    Energy Technology Data Exchange (ETDEWEB)

    Frouz, J.; Kristufek, V.; Liveckova, M.; van Loo, D.; Jacobs, P.; Van Hoorebeke, L. [Charles University of Prague, Prague (Czech Republic). Inst. of Environmental Studies

    2011-01-15

    Soil aggregates between 2 and 5 mm from 35- and 45-year-old unreclaimed post-mining sites near Sokolov (Czech Republic) were divided into two groups: spherical and prismatic. X-ray tomography indicated that prismatic aggregates consisted of fragments of claystone bonded together by amorphous clay and roots while spherical aggregates consisted of a clay matrix and organic fragments of various sizes. Prismatic aggregates were presumed to be formed by plant roots and physical processes during weathering of Tertiary mudstone, while earthworms were presumed to contribute to the formation of spherical aggregates. The effects of drying and rewetting and glucose addition on microbial respiration, microbial biomass, and counts of bacteria in these aggregates were determined. Spherical aggregates contained a greater percentage of C and N and a higher C-to-N ratio than prismatic ones. The C content of the particulate organic matter was also higher in the spherical than in the prismatic aggregates. Although spherical aggregates had a higher microbial respiration and biomass, the growth of microbial biomass in spherical aggregates was negatively correlated with initial microbial biomass, indicating competition between bacteria. Specific respiration was negatively correlated with microbial biomass. Direct counts of bacteria were higher in spherical than in prismatic aggregates. Bacterial numbers were more stable in the center than in the surface layers of the aggregates. Transmission electron microscopy indicated that bacteria often occurred as individual cells in prismatic aggregates but as small clusters of cells in spherical aggregates. Ratios of colony forming units (cultivatable bacteria) to direct counts were higher in spherical than in prismatic aggregates. Spherical aggregates also contained faster growing bacteria.

  5. Environmental exogenous factors and facial dermatitis: A case control study

    Directory of Open Access Journals (Sweden)

    Wen-Hui Wang

    2017-03-01

    Conclusions: Contact factors play an important role in facial dermatitis. Aggravation by sunlight exposure, ingestion of spicy food, or alcohol are more reported in facial dermatitis compared with nonfacial dermatitis.

  6. Reflexivity as a control factor of personal coping behavior

    OpenAIRE

    BEKHTER A.A.

    2014-01-01

    The article deals with the issue of coping behavior control. The author defines the criteria, levels and aspects of reflexivity within the framework of personal coping behavior. In conclusion the author describes the key facets of coping behavior control and how reflexivity affects them.

  7. Control of erythropoiesis by erythropoietin and stem cell factor: a novel role for Bruton's tyrosine kinase

    NARCIS (Netherlands)

    von Lindern, Marieke; Schmidt, Uwe; Beug, Hartmut

    2004-01-01

    Erythropoietin (Epo) and stem cell factor (SCF) are essential factors in the control of survival, expansion and differentiation of erythroid progenitors. Upon activation, their receptors, the EpoR and c-Kit, initiate multiple signalling pathways that control many cellular processes. To control

  8. Reactor performances and microbial communities of biogas reactors: effects of inoculum sources.

    Science.gov (United States)

    Han, Sheng; Liu, Yafeng; Zhang, Shicheng; Luo, Gang

    2016-01-01

    Anaerobic digestion is a very complex process that is mediated by various microorganisms, and the understanding of the microbial community assembly and its corresponding function is critical in order to better control the anaerobic process. The present study investigated the effect of different inocula on the microbial community assembly in biogas reactors treating cellulose with various inocula, and three parallel biogas reactors with the same inoculum were also operated in order to reveal the reproducibility of both microbial communities and functions of the biogas reactors. The results showed that the biogas production, volatile fatty acid (VFA) concentrations, and pH were different for the biogas reactors with different inocula, and different steady-state microbial community patterns were also obtained in different biogas reactors as reflected by Bray-Curtis similarity matrices and taxonomic classification. It indicated that inoculum played an important role in shaping the microbial communities of biogas reactor in the present study, and the microbial community assembly in biogas reactor did not follow the niche-based ecology theory. Furthermore, it was found that the microbial communities and reactor performances of parallel biogas reactors with the same inoculum were different, which could be explained by the neutral-based ecology theory and stochastic factors should played important roles in the microbial community assembly in the biogas reactors. The Bray-Curtis similarity matrices analysis suggested that inoculum affected more on the microbial community assembly compared to stochastic factors, since the samples with different inocula had lower similarity (10-20 %) compared to the samples from the parallel biogas reactors (30 %).

  9. Soil microbial community responses to antibiotic-contaminated manure under different soil moisture regimes.

    Science.gov (United States)

    Reichel, Rüdiger; Radl, Viviane; Rosendahl, Ingrid; Albert, Andreas; Amelung, Wulf; Schloter, Michael; Thiele-Bruhn, Sören

    2014-01-01

    Sulfadiazine (SDZ) is an antibiotic frequently administered to livestock, and it alters microbial communities when entering soils with animal manure, but understanding the interactions of these effects to the prevailing climatic regime has eluded researchers. A climatic factor that strongly controls microbial activity is soil moisture. Here, we hypothesized that the effects of SDZ on soil microbial communities will be modulated depending on the soil moisture conditions. To test this hypothesis, we performed a 49-day fully controlled climate chamber pot experiments with soil grown with Dactylis glomerata (L.). Manure-amended pots without or with SDZ contamination were incubated under a dynamic moisture regime (DMR) with repeated drying and rewetting changes of >20 % maximum water holding capacity (WHCmax) in comparison to a control moisture regime (CMR) at an average soil moisture of 38 % WHCmax. We then monitored changes in SDZ concentration as well as in the phenotypic phospholipid fatty acid and genotypic 16S rRNA gene fragment patterns of the microbial community after 7, 20, 27, 34, and 49 days of incubation. The results showed that strongly changing water supply made SDZ accessible to mild extraction in the short term. As a result, and despite rather small SDZ effects on community structures, the PLFA-derived microbial biomass was suppressed in the SDZ-contaminated DMR soils relative to the CMR ones, indicating that dynamic moisture changes accelerate the susceptibility of the soil microbial community to antibiotics.

  10. The complicated substrates enhance the microbial diversity and zinc leaching efficiency in sphalerite bioleaching system.

    Science.gov (United States)

    Xiao, Yunhua; Xu, YongDong; Dong, Weiling; Liang, Yili; Fan, Fenliang; Zhang, Xiaoxia; Zhang, Xian; Niu, Jiaojiao; Ma, Liyuan; She, Siyuan; He, Zhili; Liu, Xueduan; Yin, Huaqun

    2015-12-01

    This study used an artificial enrichment microbial consortium to examine the effects of different substrate conditions on microbial diversity, composition, and function (e.g., zinc leaching efficiency) through adding pyrite (SP group), chalcopyrite (SC group), or both (SPC group) in sphalerite bioleaching systems. 16S rRNA gene sequencing analysis showed that microbial community structures and compositions dramatically changed with additions of pyrite or chalcopyrite during the sphalerite bioleaching process. Shannon diversity index showed a significantly increase in the SP (1.460), SC (1.476), and SPC (1.341) groups compared with control (sphalerite group, 0.624) on day 30, meanwhile, zinc leaching efficiencies were enhanced by about 13.4, 2.9, and 13.2%, respectively. Also, additions of pyrite or chalcopyrite could increase electric potential (ORP) and the concentrations of Fe3+ and H+, which were the main factors shaping microbial community structures by Mantel test analysis. Linear regression analysis showed that ORP, Fe3+ concentration, and pH were significantly correlated to zinc leaching efficiency and microbial diversity. In addition, we found that leaching efficiency showed a positive and significant relationship with microbial diversity. In conclusion, our results showed that the complicated substrates could significantly enhance microbial diversity and activity of function.

  11. Microbial functional diversity associated with plant litter decomposition along a climatic gradient.

    Science.gov (United States)

    Sherman, Chen; Steinberger, Yosef

    2012-08-01

    Predicted changes in climate associated with increased greenhouse gas emissions can cause increases in global mean temperature and changes in precipitation regimes. These changes may affect key soil processes, e.g., microbial CO(2) evolution and biomass, mineralization rates, primary productivity, biodiversity, and litter decomposition, which play an important role in carbon and nutrient cycling in terrestrial ecosystems. Our study examined the changes in litter microbial communities and decomposition along a climatic gradient, ranging from arid desert to humid Mediterranean regions in Israel. Wheat straw litter bags were placed in arid, semi-arid, Mediterranean, and humid Mediterranean sites. Samples were collected seasonally over a 2-year period in order to evaluate mass loss, litter moisture, C/N ratio, bacterial colony-forming units (CFUs), microbial CO(2) evolution and biomass, microbial functional diversity, and catabolic profile. Decomposition rate was the highest during the first year of the study at the Mediterranean and arid sites. Community-level physiological profile and microbial biomass were the highest in summer, while bacterial CFUs were the highest in winter. Microbial functional diversity was found to be highest at the humid Mediterranean site, whereas substrate utilization increased at the arid site. Our results support the assumption that climatic factors control litter degradation and regulate microbial activity.

  12. CubeSat Form Factor Thermal Control Louvers

    Data.gov (United States)

    National Aeronautics and Space Administration — As small spacecraft become a part of NASA’s repertoire of missions, one reoccurring theme is an increased need for thermal control as power budgets increase and...

  13. Evaluation of factors affecting adherence to asthma controller ...

    African Journals Online (AJOL)

    Background: Adherence to controller therapy in asthma is a major concern during the management of the disease. ... The adherence to asthma treatment was rated using Morisky Medication Adherence Scale. A ..... in an outpatient setting.

  14. Flight to the future : human factors in air traffic control

    Science.gov (United States)

    1997-01-01

    The nation's air traffic control system is responsible for managing a complex : mixture of air traffic from commercial, general, corporate, and military : aviation. Despite a strong safety record, the system does suffer occasional : serious disruptio...

  15. Human factors considerations in the design and evaluation of flight deck displays and controls

    Science.gov (United States)

    2013-11-01

    The objective of this effort is to have a single source document for human factors regulatory and guidance material for flight deck displays and controls, in the interest of improving aviation safety. This document identifies guidance on human factor...

  16. Microbial Ecology of Soil Aggregation in Agroecosystems

    Science.gov (United States)

    Hofmockel, K. S.; Bell, S.; Tfailly, M.; Thompson, A.; Callister, S.

    2017-12-01

    Crop selection and soil texture influence the physicochemical attributes of the soil, which structures microbial communities and influences soil C cycling storage. At the molecular scale, microbial metabolites and necromass alter the soil environment, which creates feedbacks that influence ecosystem functions, including soil C accumulation. By integrating lab to field studies we aim to identify the molecules, organisms and metabolic pathways that control carbon cycling and stabilization in bioenergy soils. We investigated the relative influence of plants, microbes, and minerals on soil aggregate ecology at the Great Lakes Bioenergy Research experiment. Sites in WI and MI, USA have been in corn and switchgrass cropping systems for a decade. By comparing soil aggregate ecology across sites and cropping systems we are able to test the relative importance of plant, microbe, mineral influences on soil aggregate dynamics. Soil microbial communities (16S) differ in diversity and phylogeny among sites and cropping systems. FT-ICR MS revealed differences in the molecular composition of water-soluble fraction of soil organic matter for cropping systems and soil origin for both relative abundance of assigned formulas and biogeochemical classes of compounds. We found the degree of aggregation, measured by mean weighted diameter of aggregate fractions, is influenced by plant-soil interactions. Similarly, the proportion of soil aggregate fractions varied by both soil and plant factors. Differences in aggregation were reflected in differences in bacterial, but not fungal community composition across aggregate fractions, within each soil. Scanning electron microscopy revealed stark differences in mineral-organic interactions that influence the microbial niche and the accessibility of substrates within the soil. The clay soils show greater surface heterogeneity, enabling interactions with organic fraction of the soil. This is consistent with molecular data that reveal differences

  17. Factors influencing the control strategy of hybrid drive of urban public transport buses

    International Nuclear Information System (INIS)

    Barta, Dalibor; Mruzek, Martin

    2015-01-01

    The efficiency of each drives is dependent on many factors. Hybrid drives and specially the drives of urban public transport may be affected by other factors given by transport infrastructure or operational conditions. These factors condition the suitable configuration of the individual elements of hybrid drive and the establishment of good control strategy of such drive. The study of influencing factors of the control strategy is the aim of this paper. (full text)

  18. Control of wastewater N2O emissions by balancing the microbial communities using a fuzzy-logic approach

    DEFF Research Database (Denmark)

    Boiocchi, Riccardo; Gernaey, Krist; Sin, Gürkan

    2016-01-01

    (approximately 35%). On the other side, this reduction of N2O was accompanied by an increase in the aeration costs. Moreover, a plant performance evaluation under dynamic disturbances shows that the effluent quality is compromised due to higher requirements of organic carbon by denitrifying heterotrophs....... The controller can therefore be considered effective for the reduction of N2O production by AOB but would need to be coupled with a secondary control strategy ensuring a complete oxidation of the nitrogen oxides by heterotrophs to have a good effluent quality.......In this work, a fuzzy-logic controller for minimization of the nitrous oxide emission from wastewater treatment plants is developed and tested in a simulation environment. The controller is designed in order to maintain a balance between production and consumption of nitrite by AOB and NOB...

  19. Control of cellulose biosynthesis by overexpression of a transcription factor

    Energy Technology Data Exchange (ETDEWEB)

    Han, Kyung-Hwan; Ko, Jae-Heung; Kim, Won-Chan; Kim; , Joo-Yeol

    2017-05-16

    The invention relates to the over-expression of a transcription factor selected from the group consisting of MYB46, HAM1, HAM2, MYB112, WRKY11, ERF6, and any combination thereof in a plant, which can modulate and thereby modulating the cellulose content of the plant.

  20. Investigation and control of factors influencing resistance upset butt welding.

    NARCIS (Netherlands)

    Kerstens, N.F.H.

    2010-01-01

    The purpose of this work is to investigate the factors influencing the resistance upset butt welding process to obtain an understanding of the metal behaviour and welding process characteristics, so that new automotive steels can be welded with reduced development time and fewer failures in

  1. Molecular Factors Controlling Photosynthetic Light Harvesting by Carotenoids

    Czech Academy of Sciences Publication Activity Database

    Polívka, Tomáš; Frank, H.A.

    2010-01-01

    Roč. 43, č. 8 (2010), s. 1125-1134 ISSN 0001-4842 Institutional research plan: CEZ:AV0Z50510513 Keywords : carotenoids * energy transfer * photosynthesis * light-harvesting Subject RIV: BO - Biophysics Impact factor: 21.840, year: 2010

  2. Factors determining the use of botanical insect pest control methods ...

    African Journals Online (AJOL)

    A farm survey was conducted in three representative administrative districts of the Lake Victoria Basin (LVB), Kenya to document farmers' indigenous knowledge and the factors that influence the use of botanicals instead of synthetic insecticides in insect pest management. A total of 65 farm households were randomly ...

  3. Risk factors for measles among adults in Tianjin, China: Who should be controls in a case-control study?

    Science.gov (United States)

    Wagner, Abram L; Boulton, Matthew L; Gillespie, Brenda W; Zhang, Ying; Ding, Yaxing; Carlson, Bradley F; Luo, Xiaoyan; Montgomery, JoLynn P; Wang, Xiexiu

    2017-01-01

    Control groups in previous case-control studies of vaccine-preventable diseases have included people immune to disease. This study examines risk factors for measles acquisition among adults 20 to 49 years of age in Tianjin, China, and compares findings using measles IgG antibody-negative controls to all controls, both IgG-negative and IgG-positive. Measles cases were sampled from a disease registry, and controls were enrolled from community registries in Tianjin, China, 2011-2015. Through a best subsets selection procedure, we compared which variables were selected at different model sizes when using IgG-negative controls or all controls. We entered risk factors for measles in two separate logistic regression models: one with measles IgG-negative controls and the other with all controls. The study included 384 measles cases and 1,596 community controls (194 IgG-negative). Visiting a hospital was an important risk factor. For specialty hospitals, the odds ratio (OR) was 4.53 (95% confidence interval (CI): 1.28, 16.03) using IgG-negative controls, and OR = 5.27 (95% CI: 2.73, 10.18) using all controls. Variables, such as age or length of time in Tianjin, were differentially selected depending on the control group. Individuals living in Tianjin ≤3 years had 2.87 (95% CI: 1.46, 5.66) times greater odds of measles case status compared to all controls, but this relationship was not apparent for IgG-negative controls. We recommend that case-control studies examining risk factors for infectious diseases, particularly in the context of transmission dynamics, consider antibody-negative controls as the gold standard.

  4. Soil-Borne Microbial Functional Structure across Different Land Uses

    NARCIS (Netherlands)

    Kuramae, E.E.; Zhou, J.Z.; Kowalchuk, G.A.; van Veen, J.A..

    2014-01-01

    Land use change alters the structure and composition of microbial communities. However, the links between environmental factors and microbial functions are not well understood. Here we interrogated the functional structure of soil microbial communities across different land uses. In a multivariate

  5. Soil-borne microbial functional structure across different land uses

    NARCIS (Netherlands)

    Kuramae, Eiko E; Zhou, Jizhong Z; Kowalchuk, George A; van Veen, Johannes A

    2014-01-01

    Land use change alters the structure and composition of microbial communities. However, the links between environmental factors and microbial functions are not well understood. Here we interrogated the functional structure of soil microbial communities across different land uses. In a multivariate

  6. Population prevalence and control of cardiovascular risk factors: What electronic medical records tell us

    Directory of Open Access Journals (Sweden)

    Arantxa Catalán-Ramos

    2014-01-01

    Conclusions: Hypertension was the most prevalent cardiovascular risk factor in the Catalan population attended at primary care centers. About two thirds of individuals with hypertension or DM2 were adequately controlled; hypercholesterolemia control was particularly low.

  7. Something new from something old? Fracking stimulated microbial processes

    Science.gov (United States)

    Wrighton, K. C.; Daly, R. A.; Hoyt, D.; Trexler, R.; McRae, J.; Wilkins, M.; Mouser, P. J.

    2015-12-01

    Hydraulic fracturing, colloquially known as "fracking", is employed for effective gas and oil recovery in deep shales. This process injects organisms and liquids from the surface into the deep subsurface (~2500 m), exposing microorganisms to high pressures, elevated temperatures, chemical additives, and brine-level salinities. Here we use assembly-based metagenomics to create a metabolic blueprint from an energy-producing Marcellus shale well over a 328-day period. Using this approach we ask the question: What abiotic and biotic factors drive microbial metabolism and thus biogeochemical cycling during natural gas extraction? We found that after 49 days, increased salinity in produced waters corresponded to a shift in the microbial community, with only organisms that encode salinity adaptations detected. We posit that organic compatible solutes, produced by organisms adapting to increased salinity, fuels a methylamine-driven ecosystem in fractured shale. This metabolic network ultimately results in biogenic methane production from members of Methanohalophilus and Methanolobus. Proton NMR validated these genomic hypotheses, with mono-methylamine being highest in the input material, but detected throughout the sampling. Beyond abiotic constraints, our genomic investigations revealed that viruses can be linked to key members of the microbial community, potentially releasing methylamine osmoprotectants and impacting bacterial strain variation. Collectively our results indicate that adaptation to high salinity, metabolism in the absence of oxidized electron acceptors, and viral predation are controlling factors mediating microbial community metabolism during hydraulic fracturing of the deep subsurface.

  8. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Energy Technology Data Exchange (ETDEWEB)

    He, Yujie [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Yang, Jinyan [Univ. of Georgia, Athens, GA (United States). Warnell School of Forestry and Natural Resources; Northeast Forestry Univ., Harbin (China). Center for Ecological Research; Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy; Harden, Jennifer W. [U.S. Geological Survey, Menlo Park, CA (United States); McGuire, Anthony D. [Alaska Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit; Liu, Yaling [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Wang, Gangsheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division; Gu, Lianhong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2015-11-20

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here in this study we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (<2% of soil organic carbon) and soil RH (7.5 ± 2.4 PgCyr-1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4-0.6) in the simulated spatial pattern of soil RH with both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = -0.43 to -0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  9. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Science.gov (United States)

    He, Yujie; Yang, Jinyan; Zhuang, Qianlai; Harden, Jennifer W.; McGuire, A. David; Liu, Yaling; Wang, Gangsheng; Gu, Lianhong

    2015-01-01

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4–0.6) in the simulated spatial pattern of soil RHwith both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  10. Investigation and control of factors influencing resistance upset butt welding.

    OpenAIRE

    Kerstens, N.F.H.

    2010-01-01

    The purpose of this work is to investigate the factors influencing the resistance upset butt welding process to obtain an understanding of the metal behaviour and welding process characteristics, so that new automotive steels can be welded with reduced development time and fewer failures in production. In principle the welding process is rather simple, the materials to be joined are clamped between two electrodes and pressed together. Because there is an interface present with a higher resist...

  11. Hypertension control and other cardiovascular risk factors among ...

    African Journals Online (AJOL)

    Their age, sex weight, height, blood pressure, fasting capillary blood glucose, lipid and renal profiles, hypertension and diabetes therapy were ascertained. Results: Hypertension prevalence was 54.7%. Treatment and control rates of hypertension were 81.7% and 34% respectively. Hypertensive patients were older, more ...

  12. Other Factors That Affect Heart Disease: Birth Control Pills

    Science.gov (United States)

    ... are considering using one, keep these guidelines in mind: Don't mix smoking and "the pill." If you smoke cigarettes, make a serious effort to quit. If you cannot quit, choose a different form of birth control. Cigarette smoking boosts the risk of serious health problems from birth ...

  13. Control of Risk Factors For Nephropathy Among Nigerian Outpatients

    African Journals Online (AJOL)

    Zamzar

    54.7%) had diabetes between 1 and 5 years, and 95% were on antidiabetic drugs, most commonly both a ... (3.1%) had the combination of good glycaemic control, good blood pressure ... and the average of the three readings was used as an.

  14. Factors Relating to Staff Attributions of Control over Challenging Behaviour

    Science.gov (United States)

    Dilworth, Jennifer A.; Phillips, Neil; Rose, John

    2011-01-01

    Background: Previous research has suggested that severity of intellectual disability (ID) and topography of behaviour may influence staff causal attributions regarding challenging behaviour. Subsequently, these causal attributions may influence helping behaviours. This study investigated the relationship between attributions of control over…

  15. Stabilizing the baseline current of a microbial fuel cell-based biosensor through overpotential control under non-toxic conditions

    NARCIS (Netherlands)

    Stein, N.E.; Hamelers, H.V.M.; Buisman, C.J.N.

    2010-01-01

    A MFC-based biosensor can act as online toxicity sensor Electrical current is a direct linear measure for metabolic activity of electrochemically active microorganisms Microorganisms gain energy from anodic overpotential and current strongly depends on anodic overpotential Therefore control of

  16. Effectiveness of prerequisites and the HACCP plan in the control of microbial contamination in ice cream and cheese companies.

    Science.gov (United States)

    Domenech, Eva; Amorós, José Antonio; Escriche, Isabel

    2013-03-01

    In food safety, implementation of prerequisites and application of Hazard Analysis and Critical Control Points (HACCP) guarantee the control of processes, and microbiological criteria permit validation of their effectiveness. With these aims in mind, this article presents the results obtained by the official control carried out by the Valencian administration in ice cream and cheese companies, located in the Xativa/Ontinyente area (Valencian region, Spain) in the period between 2005 and 2010. The audits of Good Hygienic Practices (GHP) and HACCP show that "Structure & Design" followed by "Hygiene & Cleaning" and "Traceability" were the evaluated items with most nonconformities. Pathogenic microorganisms were not found in any of the final products analyzed. Microorganism indicators of unhygienic conditions were present in 100% of the analyses; however, 87.98% of them had low levels, which did not exceed the microbiological criteria. These results highlight the general good effectiveness of the safety management systems implemented and emphasize that companies and official control must continue working in order to guarantee the consumers' welfare.

  17. Searching for microbial biological control candidates for invasive grasses: coupling expanded field research with strides in biotechnology and grassland restoration

    Science.gov (United States)

    Highly invasive grasses (e.g. Bromus spp., Pennisetum ciliare, Taeniatherum caput-medusae) are largely unabated in much of the arid Western U.S., despite more than 70 years of control attempts with a wide array of tools and management practices. The development and sustained integration of new appro...

  18. Microbial Species and Functional Diversity in Rice Rhizosphere of High-yield Special Ecological Areas

    Directory of Open Access Journals (Sweden)

    PAN Li-yuan

    2016-11-01

    Full Text Available Taoyuan, Yunnan Province is a special eco-site which keeps the highest yield records of rice cultivation in small planting areas. Soil microbial species and functional diversity were evaluated using cultivation method and BIOLOG ecoplates. The results showed that the microbial community of the high yield region was more abundant, and the total microbial population was 2 times of the control, furthermore, the areas belonged to the healthy "bacteria" soil, which was showed as bacteria > actinomycetes > fungi. Bacteria were the dominant populations in the rhizosphere of high yielding rice field, and the yield formation of rice was not correlated with the depth of soil layers. In order to obtain more species diversity information, Shannon diversity index H, Shannon evenness index E and Simpson index D were analyzed, and the results showed that microbial community diversity and evenness were not the main differences between the high and general yield areas. Then, the functional diversity of soil microbial community was investigated through the average well color development(AWCD and diversity index analyses. The results of AWCD analysis indicated that the metabolic activity of soil microbial community in high yield paddy soils were stronger than the control. Moreover, the difference range from large to small showed as tillering stage > harvest period > seedling period > rotation period, the stronger the rice growth, the greater the difference between the high yield region and the control. At tillering stage and harvest stage, due to the vigorous plant growth, the root exudates were rich, and the microbial communities of high yield paddy soils showed a strong metabolic activity and strong ability to use carbon sources. The results of Shannon, Simpson and McIntosh indices analysis indicated that common microbial species was not a key factor affecting the yield of rice. Tillering stage was a key period for the growth of high yield rice, and many

  19. Microbial Anaerobic Digestion (Bio-Digesters) as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    Science.gov (United States)

    Manyi-Loh, Christy E.; Mamphweli, Sampson N.; Meyer, Edson L.; Okoh, Anthony I.; Makaka, Golden; Simon, Michael

    2013-01-01

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications. PMID:24048207

  20. Microbial Anaerobic Digestion (Bio-Digesters as an Approach to the Decontamination of Animal Wastes in Pollution Control and the Generation of Renewable Energy

    Directory of Open Access Journals (Sweden)

    Golden Makaka

    2013-09-01

    Full Text Available With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  1. Microbial anaerobic digestion (bio-digesters) as an approach to the decontamination of animal wastes in pollution control and the generation of renewable energy.

    Science.gov (United States)

    Manyi-Loh, Christy E; Mamphweli, Sampson N; Meyer, Edson L; Okoh, Anthony I; Makaka, Golden; Simon, Michael

    2013-09-17

    With an ever increasing population rate; a vast array of biomass wastes rich in organic and inorganic nutrients as well as pathogenic microorganisms will result from the diversified human, industrial and agricultural activities. Anaerobic digestion is applauded as one of the best ways to properly handle and manage these wastes. Animal wastes have been recognized as suitable substrates for anaerobic digestion process, a natural biological process in which complex organic materials are broken down into simpler molecules in the absence of oxygen by the concerted activities of four sets of metabolically linked microorganisms. This process occurs in an airtight chamber (biodigester) via four stages represented by hydrolytic, acidogenic, acetogenic and methanogenic microorganisms. The microbial population and structure can be identified by the combined use of culture-based, microscopic and molecular techniques. Overall, the process is affected by bio-digester design, operational factors and manure characteristics. The purpose of anaerobic digestion is the production of a renewable energy source (biogas) and an odor free nutrient-rich fertilizer. Conversely, if animal wastes are accidentally found in the environment, it can cause a drastic chain of environmental and public health complications.

  2. Correlation analysis of the physiological factors controlling fundamental voice frequency.

    Science.gov (United States)

    Atkinson, J E

    1978-01-01

    A technique has been developed to obtain a quantitative measure of correlation between electromyographic (EMG) activity of various laryngeal muscles, subglottal air pressure, and the fundamental frequency of vibration of the vocal folds (Fo). Data were collected and analyzed on one subject, a native speaker of American English. The results show that an analysis of this type can provide a useful measure of correlation between the physiological and acoustical events in speech and, furthermore, can yield detailed insights into the organization and nature of the speech production process. In particular, based on these results, a model is suggested of Fo control involving laryngeal state functions that seems to agree with present knowledge of laryngeal control and experimental evidence.

  3. Engineering human factors into the Westinghouse advanced control room

    International Nuclear Information System (INIS)

    Easter, J.R.

    1987-01-01

    By coupling the work of the Riso Laboratory in Denmark on human behaviour with new digital computation and display technology, Westinghouse has developed a totally new control room design. This design features a separate, co-ordinated work station to support the systems management role in decision making, as well as robust alarm and display systems. This coupling of the functional and physical data presentation is now being implemented in test facilities. (author)

  4. Effect of inclusion of different levels of silage on rumen microbial population and microbial protein synthesis in dairy steers fed on rice straw

    Directory of Open Access Journals (Sweden)

    Thien Truong Giang Nguyen

    2017-02-01

    Full Text Available Objective Leucaena leucocephala (Leucaena is a perennial tropical legume that can be directly grazed or harvested and offered to ruminants as hay, silage, or fresh. However, Leucaena contain phenolic compounds, which are considered anti-nutritional factors as these may reduce intake, digestibility and thus animal performance. Therefore, the objective of this experiment was to determine effects of Leucaena silage (LS feeding levels on rumen microbial populations, N-balance and microbial protein synthesis in dairy steers. Methods Four, rumen fistulated dairy steers with initial weight of 167±12 kg were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. Treatments were as followings: T1 = untreated rice straw (RS; Control, T2 = 70% RS+30% LS, T3 = 40% RS+60% LS, and T4 = 100% LS. Dairy steers were fed rice straw and LS ad libitum and supplemented with concentrate at 0.2% of body weight/d. Results Results revealed that the rumen microbial population, especially cellulolytic, proteolytic bacteria and fungal zoospores were enhanced in steers that received 60% of LS (p0.05. Protozoal population was linearly decreased with increasing level of LS (p<0.05. Moreover, N-balance and microbial protein synthesis were enhanced by LS feeding (p<0.05 and were the highest in 60% LS group. Conclusion Based on this study, it could be concluded that replacement of RS with 60% LS significantly improved microbial population and microbial protein synthesis in diary steers.

  5. Factors Controlling the Pharmacokinetics, Biodistribution and Intratumoral Penetration of Nanoparticles

    Science.gov (United States)

    Ernsting, Mark J.; Murakami, Mami; Roy, Aniruddha; Li, Shyh-Dar

    2014-01-01

    Nanoparticle drug delivery to the tumor is impacted by multiple factors: nanoparticles must evade clearance by renal filtration and the reticuloendothelial system, extravasate through the enlarged endothelial gaps in tumors, penetrate through dense stroma in the tumor microenvironment to reach the tumor cells, remain in the tumor tissue for a prolonged period of time, and finally release the active agent to induce pharmacological effect. The physicochemical properties of nanoparticles such as size, shape, surface charge, surface chemistry (PEGylation, ligand conjugation) and composition affect the pharmacokinetics, biodistribution, intratumoral penetration and tumor bioavailability. On the other hand, tumor biology (blood flow, perfusion, permeability, interstitial fluid pressure and stroma content) and patient characteristics (age, gender, tumor type, tumor location, body composition and prior treatments) also have impact on drug delivery by nanoparticles. It is now believed that both nanoparticles and the tumor microenvironment have to be optimized or adjusted for optimal delivery. This review provides a comprehensive summary of how these nanoparticle and biological factors impact nanoparticle delivery to tumors, with discussion on how the tumor microenvironment can be adjusted and how patients can be stratified by imaging methods to receive the maximal benefit of nanomedicine. Perspectives and future directions are also provided. PMID:24075927

  6. Factors Controlling Methane in Arctic Lakes of Southwest Greenland.

    Science.gov (United States)

    Northington, Robert M; Saros, Jasmine E

    2016-01-01

    We surveyed 15 lakes during the growing season of 2014 in Arctic lakes of southwest Greenland to determine which factors influence methane concentrations in these systems. Methane averaged 2.5 μmol L-1 in lakes, but varied a great deal across the landscape with lakes on older landscapes farther from the ice sheet margin having some of the highest values of methane reported in lakes in the northern hemisphere (125 μmol L-1). The most important factors influencing methane in Greenland lakes included ionic composition (SO4, Na, Cl) and chlorophyll a in the water column. DOC concentrations were also related to methane, but the short length of the study likely underestimated the influence and timing of DOC on methane concentrations in the region. Atmospheric methane concentrations are increasing globally, with freshwater ecosystems in northern latitudes continuing to serve as potentially large sources in the future. Much less is known about how freshwater lakes in Greenland fit in the global methane budget compared to other, more well-studied areas of the Arctic, hence our work provides essential data for a more complete view of this rapidly changing region.

  7. Idiopathic epistaxis and meteorological factors: case-control study.

    Science.gov (United States)

    Jelavic, B; Majstorovic, Z; Kordić, M; Leventić, M; Grgić, M V; Baudoin, T

    2015-01-01

    The aim of this study was to determine the relationship between the occurrence of idiopathic epistaxis and daily values of air pressure, temperature, and humidity. We also investigated whether biometeorological forecasts should be addressed to persons with a history of nosebleed diathesis. We analyzed consecutive idiopathic epistaxis events over a 3-year period. Patients were included if they had been in the municipality of Mostar, Bosnia and Herzegovina at least 24 hours before the epistaxis occurrence. The monthly variation in epistaxis events was determined. Epistaxis days (Days "0", 0 = day with epistaxis occurrence) and selected nonepistaxis days (Days "-1", -1 = each first single day without epistaxis prior to Day 0) were compared according to daily values of mean, minimum, and maximum temperature; diurnal temperature range; minimum and maximum atmospheric pressure; diurnal pressure range; and mean relative humidity. The greatest and smallest percentage of epistaxis events occurred in the months of March and August, respectively. There were no significant differences between Days 0 and Days -1 with respect to the examined meteorological factors. In this region with a Mediterranean climate, we found a seasonal variation with an incidence peak during the spring transition months, but we did not identify any meteorological trigger factors for epistaxis. Thus, there is no need for biometeorological forecasts to be addressed to persons with a history of nosebleed diathesis.

  8. Factores de riesgo para carcinoma basocelular: Estudio de casos-controles en Córdoba Risk factors for basal cell carcinoma: Case-control study in Cordoba

    Directory of Open Access Journals (Sweden)

    Alejandro Ruiz Lascano

    2005-12-01

    Full Text Available El carcinoma basocelular es una enfermedad compleja. Su etiología es todavía poco clara y a pesar de su frecuencia hay pocos datos sobre factores de riesgo. Nosotros evaluamos factores de riesgo potenciales para carcinoma basocelular en una población de Córdoba (Argentina. Este estudio de casos y controles incluyó a 88 casos nuevos de carcinoma basocelular, y 88 controles pareados por sexo y edad. Los siguientes factores de riesgo fueron significativos en el análisis multivariado: fototipos I, II y III, exposición solar recreativa alta después de los 20 años de edad, exposición solar alta en vacaciones en la playa y la presencia de queratosis actínicas.Basal cell carcinoma is undoubtedly a complex disease. Its etiology is still unclear and despite its frequency, there is a paucity of data on its risk factors. We assessed potential risk factors for basal cell carcinoma in a population from Córdoba (Argentina. This case-control study involved 88 newly diagnosed cases and 88 controls, matched by age and sex. The following risk factors were significant in the multivariate analysis: skin type I-II-III, high recreational sun exposure after 20 years of age, high sun exposure for beach holidays and actinic keratosis.

  9. Microbial micropatches within microbial hotspots

    Science.gov (United States)

    Smith, Renee J.; Tobe, Shanan S.; Paterson, James S.; Seymour, Justin R.; Oliver, Rod L.; Mitchell, James G.

    2018-01-01

    The spatial distributions of organism abundance and diversity are often heterogeneous. This includes the sub-centimetre distributions of microbes, which have ‘hotspots’ of high abundance, and ‘coldspots’ of low abundance. Previously we showed that 300 μl abundance hotspots, coldspots and background regions were distinct at all taxonomic levels. Here we build on these results by showing taxonomic micropatches within these 300 μl microscale hotspots, coldspots and background regions at the 1 μl scale. This heterogeneity among 1 μl subsamples was driven by heightened abundance of specific genera. The micropatches were most pronounced within hotspots. Micropatches were dominated by Pseudomonas, Bacteroides, Parasporobacterium and Lachnospiraceae incertae sedis, with Pseudomonas and Bacteroides being responsible for a shift in the most dominant genera in individual hotspot subsamples, representing up to 80.6% and 47.3% average abundance, respectively. The presence of these micropatches implies the ability these groups have to create, establish themselves in, or exploit heterogeneous microenvironments. These genera are often particle-associated, from which we infer that these micropatches are evidence for sub-millimetre aggregates and the aquatic polymer matrix. These findings support the emerging paradigm that the microscale distributions of planktonic microbes are numerically and taxonomically heterogeneous at scales of millimetres and less. We show that microscale microbial hotspots have internal structure within which specific local nutrient exchanges and cellular interactions might occur. PMID:29787564

  10. Tobacco control policy development in the European Union: do political factors matter?

    NARCIS (Netherlands)

    Bosdriesz, Jizzo R.; Willemsen, Marc C.; Stronks, Karien; Kunst, Anton E.

    2015-01-01

    There has been much variation between European countries in the development of tobacco control policy. Not much is known about the factors that shape this variation. This study aimed to assess the role of political factors in tobacco control policy development. We used data from 11 European

  11. Human Factors Analysis of Pipeline Monitoring and Control Operations: Final Technical Report

    Science.gov (United States)

    2008-11-26

    The purpose of the Human Factors Analysis of Pipeline Monitoring and Control Operations project was to develop procedures that could be used by liquid pipeline operators to assess and manage the human factors risks in their control rooms that may adv...

  12. Risk factors for Creutzfeldt-Jakob disease: a reanalysis of case-control studies.

    NARCIS (Netherlands)

    D.P.W.M. Wientjens (Dorothee); Z. Davanipour; K. Kondo; W.B. Matthews; R.G. Will (Robert); C.M. van Duijn (Cornelia); A. Hofman (Albert)

    1996-01-01

    textabstractTo review the evidence for risk factors of Creutzfeldt-Jakob disease (CJD), we pooled and reanalyzed the raw data of three case-control studies. The pooled data set comprised 178 patients and 333 control subjects. The strength of association between CJD and putative risk factors was

  13. Relating microbial community structure to functioning in forest soil organic carbon transformation and turnover.

    Science.gov (United States)

    You, Yeming; Wang, Juan; Huang, Xueman; Tang, Zuoxin; Liu, Shirong; Sun, Osbert J

    2014-03-01

    Forest soils store vast amounts of terrestrial carbon, but we are still limited in mechanistic understanding on how soil organic carbon (SOC) stabilization or turnover is controlled by biotic and abiotic factors in forest ecosystems. We used phospholipid fatty acids (PLFAs) as biomarker to study soil microbial community structure and measured activities of five extracellular enzymes involved in the degradation of cellulose (i.e., β-1,4-glucosidase and cellobiohydrolase), chitin (i.e., β-1,4-N-acetylglucosaminidase), and lignin (i.e., phenol oxidase and peroxidase) as indicators of soil microbial functioning in carbon transformation or turnover across varying biotic and abiotic conditions in a typical temperate forest ecosystem in central China. Redundancy analysis (RDA) was performed to determine the interrelationship between individual PFLAs and biotic and abiotic site factors as well as the linkage between soil microbial structure and function. Path analysis was further conducted to examine the controls of site factors on soil microbial community structure and the regulatory pathway of changes in SOC relating to microbial community structure and function. We found that soil microbial community structure is strongly influenced by water, temperature, SOC, fine root mass, clay content, and C/N ratio in soils and that the relative abundance of Gram-negative bacteria, saprophytic fungi, and actinomycetes explained most of the variations in the specific activities of soil enzymes involved in SOC transformation or turnover. The abundance of soil bacterial communities is strongly linked with the extracellular enzymes involved in carbon transformation, whereas the abundance of saprophytic fungi is associated with activities of extracellular enzymes driving carbon oxidation. Findings in this study demonstrate the complex interactions and linkage among plant traits, microenvironment, and soil physiochemical properties in affecting SOC via microbial regulations.

  14. Scaffolds for Controlled Release of Cartilage Growth Factors.

    Science.gov (United States)

    Morille, Marie; Venier-Julienne, Marie-Claire; Montero-Menei, Claudia N

    2015-01-01

    In recent years, cell-based therapies using adult stem cells have attracted considerable interest in regenerative medicine. A tissue-engineered construct for cartilage repair should provide a support for the cell and allow sustained in situ delivery of bioactive factors capable of inducing cell differentiation into chondrocytes. Pharmacologically active microcarriers (PAMs), made of biodegradable and biocompatible poly (D,L-lactide-co-glycolide acid) (PLGA), are a unique system which combines these properties in an adaptable and simple microdevice. This device relies on nanoprecipitation of proteins encapsulated in polymeric microspheres with a solid in oil in water emulsion-solvent evaporation process, and their subsequent coating with extracellular matrix protein molecules. Here, we describe their preparation process, and some of their characterization methods for an application in cartilage tissue engineering.

  15. MICROBIAL SURFACTANTS IN ENVIRONMENTAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-08-01

    Full Text Available It was shown literature and own experimental data concerning the use of microbial surface active glycolipids (rhamno-, sophoro- and trehalose lipids and lipopeptides for water and soil purification from oil and other hydrocarbons, removing toxic heavy metals (Cu2+, Cd2+, Ni2+, Pb2+, degradation of complex pollution (oil and other hydrocarbons with heavy metals, and the role of microbial surfactants in phytoremediation processes. The factors that limit the use of microbial surfactants in environmental technologies are discussed. Thus, at certain concentrations biosurfactant can exhibit antimicrobial properties and inhibit microorganisms destructing xenobiotics. Microbial biodegradability of surfactants may also reduce the effectiveness of bioremediation. Development of effective technologies using microbial surfactants should include the following steps: monitoring of contaminated sites to determine the nature of pollution and analysis of the autochthonous microbiota; determining the mode of surfactant introduction (exogenous addition of stimulation of surfactant synthesis by autochthonous microbiota; establishing an optimal concentration of surfactant to prevent exhibition of antimicrobial properties and rapid biodegradation; research both in laboratory and field conditions.

  16. Real-time corrosion monitoring of steel influenced by microbial activity (SRB) under controlled seawater injection conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kane, Russell D. [InterCorr International, Inc., 14503 Bammel N. Houston Road, Suite 300, Houston, TX 77019 (United States); Campbell, Scott [Commercial Microbiology Inc., 10400 Westoffice Drive Suite 107, Houston, TX 77042 (United States)

    2004-07-01

    An experimental study of microbiologically influenced corrosion (MIC) was conducted involving online, real-time monitoring of a bio-film loop under controlled conditions simulating oil field water handling and injection. Bio-film growth, MIC and biocide efficacy were monitored using an automated, multi-technique monitoring system including linear polarization resistance, electrochemical noise and harmonic distortion analysis. This data was correlated with conventional off-line methods to differentiate conditions of varying MIC activity in real-time to facilitate quick assessment and operator intervention. (authors)

  17. Microbial keratitis in West and East Malaysia

    OpenAIRE

    Vanitha Ratnalingam; Thiageswari Umapathy; Kala Sumugam; Hanida Hanafi; Shamala Retnasabapathy

    2017-01-01

    AIM: To evaluate the epidemiological and etiological factors of microbial keratitis seen in tertiary hospitals in West and East Malaysia.METHODS: A total of 207 patients were enrolled. Patients referred for microbial keratitis to Sungai Buloh Hospital and Kuala Lumpur Hospital in West Malaysia and Queen Elizabeth Hospital and Kuching General Hospital in East Malaysia were recruited. Risk factors were documented. Corneal scrapings for microscopy and culture were performed.RESULTS: The most com...

  18. Factors controlling sulfur gas exchange in Sphagnum-dominated wetlands

    Science.gov (United States)

    Demello, William Zamboni; Hines, Mark E.; Bayley, Suzanne E.

    1992-01-01

    Atmosphere-peatland exchange of reduced sulfur gases was determined seasonally in fen in NH, and in an artificially-acidified fen at the Experimental Lakes Area (ELA) in Canada. Dimethyl sulfide (DMS) dominated gas fluxes at rates as high as 400 nmol/m(sup -2)hr(sup -1). DMS fluxes measured using enclosures were much higher than those calculated using a stagnant-film model, suggesting that Sphagnum regulated efflux. Temperature controlled diel and seasonal variability in DMS emissions. Use of differing enclosure techniques indicated that vegetated peatlands consume atmospheric carbonyl sulfide. Sulfate amendments caused DMS and methane thiol concentrations in near-surface pore waters to increase rapidly, but fluxes of these gases to the atmosphere were not affected. However, emission data from sites experiencing large differences in rates of sulfate deposition from the atmosphere suggested that chronic elevated sulfate inputs enhance DMS emissions from northern wetlands.

  19. Factors controlling the regional distribution of vanadium in ground water

    Science.gov (United States)

    Wright, Michael T.; Belitz, Kenneth

    2010-01-01

    Although the ingestion of vanadium (V) in drinking water may have possible adverse health effects, there have been relatively few studies of V in groundwater. Given the importance of groundwater as a source of drinking water in many areas of the world, this study examines the potential sources and geochemical processes that control the distribution of V in groundwater on a regional scale. Potential sources of V to groundwater include dissolution of V rich rocks, and waste streams from industrial processes. Geochemical processes such as adsorption/desorption, precipitation/dissolution, and chemical transformations control V concentrations in groundwater. Based on thermodynamic data and laboratory studies, V concentrations are expected to be highest in samples collected from oxic and alkaline groundwater. However, the extent to which thermodynamic data and laboratory results apply to the actual distribution of V in groundwater is not well understood. More than 8400 groundwater samples collected in California were used in this study. Of these samples, high (> or = 50 μg/L) and moderate (25 to 49 μg/L) V concentrations were most frequently detected in regions where both source rock and favorable geochemical conditions occurred. The distribution of V concentrations in groundwater samples suggests that significant sources of V are mafic and andesitic rock. Anthropogenic activities do not appear to be a significant contributor of V to groundwater in this study. High V concentrations in groundwater samples analyzed in this study were almost always associated with oxic and alkaline groundwater conditions, which is consistent with predictions based on thermodynamic data.

  20. Strain Specific Factors Control Effector Gene Silencing in Phytophthora sojae.

    Directory of Open Access Journals (Sweden)

    Sirjana Devi Shrestha

    Full Text Available The Phytophthora sojae avirulence gene Avr3a encodes an effector that is capable of triggering immunity on soybean plants carrying the resistance gene Rps3a. P. sojae strains that express Avr3a are avirulent to Rps3a plants, while strains that do not are virulent. To study the inheritance of Avr3a expression and virulence towards Rps3a, genetic crosses and self-fertilizations were performed. A cross between P. sojae strains ACR10 X P7076 causes transgenerational gene silencing of Avr3a allele, and this effect is meiotically stable up to the F5 generation. However, test-crosses of F1 progeny (ACR10 X P7076 with strain P6497 result in the release of silencing of Avr3a. Expression of Avr3a in the progeny is variable and correlates with the phenotypic penetrance of the avirulence trait. The F1 progeny from a direct cross of P6497 X ACR10 segregate for inheritance for Avr3a expression, a result that could not be explained by parental imprinting or heterozygosity. Analysis of small RNA arising from the Avr3a gene sequence in the parental strains and hybrid progeny suggests that the presence of small RNA is necessary but not sufficient for gene silencing. Overall, we conclude that inheritance of the Avr3a gene silenced phenotype relies on factors that are variable among P. sojae strains.

  1. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard

    Directory of Open Access Journals (Sweden)

    P. Kotas

    2018-03-01

    Full Text Available The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS, and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs. We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects, mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  2. Soil microbial biomass, activity and community composition along altitudinal gradients in the High Arctic (Billefjorden, Svalbard)

    Science.gov (United States)

    Kotas, Petr; Šantrůčková, Hana; Elster, Josef; Kaštovská, Eva

    2018-03-01

    The unique and fragile High Arctic ecosystems are vulnerable to global climate warming. The elucidation of factors driving microbial distribution and activity in arctic soils is essential for a comprehensive understanding of ecosystem functioning and its response to environmental change. The goals of this study were to investigate microbial biomass and activity, microbial community structure (MCS), and their environmental controls in soils along three elevational transects in the coastal mountains of Billefjorden, central Svalbard. Soils from four different altitudes (25, 275, 525 and 765 m above sea level) were analyzed for a suite of characteristics including temperature regimes, organic matter content, base cation availability, moisture, pH, potential respiration, and microbial biomass and community structure using phospholipid fatty acids (PLFAs). We observed significant spatial heterogeneity of edaphic properties among transects, resulting in transect-specific effects of altitude on most soil parameters. We did not observe any clear elevation pattern in microbial biomass, and microbial activity revealed contrasting elevational patterns between transects. We found relatively large horizontal variability in MCS (i.e., between sites of corresponding elevation in different transects), mainly due to differences in the composition of bacterial PLFAs, but also a systematic altitudinal shift in MCS related to different habitat preferences of fungi and bacteria, which resulted in high fungi-to-bacteria ratios at the most elevated sites. The biological soil crusts on these most elevated, unvegetated sites can host microbial assemblages of a size and activity comparable to those of the arctic tundra ecosystem. The key environmental factors determining horizontal and vertical changes in soil microbial properties were soil pH, organic carbon content, soil moisture and Mg2+ availability.

  3. Risk Factors Profile of Shoulder Dystocia in Oman: A Case Control Study

    OpenAIRE

    Maha M. Al-Khaduri; Rania Mohammed Abudraz; Sayed G. Rizvi; Yahya M. Al-Farsi

    2014-01-01

    Objective: This study aimed to assess the risk factor profile of shoulder dystocia and associated neonatal complications in Oman, a developing Arab country. Methods: A retrospective case-control study was conducted among 111 cases with dystocia and 111 controls, identified during 1994-2006 period in a tertiary care hospital in Oman. Controls were randomly selected among women who did not have dystocia, and were matched to cases on the day of delivery. Data related to potential risk factor...

  4. Research progress on influencing factors of hospital infection and prevention and control measures

    Directory of Open Access Journals (Sweden)

    He Wenlong

    2015-03-01

    Full Text Available Hospital infections are associated with the emergence of hospitals. As the understanding of hospital infections deepen and prevention and control measures improve, hospital infections have become manageable. In recent years, affected by the increase in invasive treatment technology, antimicrobial abuse, and other factors, the control of hospital infection has encountered new problems. This paper reviews the influencing factors of hospital infections and their prevention and control measures.

  5. AN ASSESSMENT OF FACTORS AFFECTING MATERIAL STOCK CONTROL PRACTICE ON SELECTED CONSTRUCTION SITES IN NIGERIA

    OpenAIRE

    Adafin, Johnson Kayode; Ayodele, Elijah Olusegun; Daramola, Olufemi

    2011-01-01

    This research examines the stock control methods utilized by construction firms on construction sites with a view to assessing the factors affecting material stock control practice by construction firms as well as determining the impact of factors affecting material stock control on building project performance. Data were collected with the aid of well-structured questionnaire administered on a number of construction professionals and technicians in some randomly selected building constructio...

  6. The influence of temperature and moisture contents regimes on the aerobic microbial activity of a biosolids composting blend.

    Science.gov (United States)

    Liang, C; Das, K C; McClendon, R W

    2003-01-01

    To understand the relationships between temperature, moisture content, and microbial activity during the composting of biosolids (municipal wastewater treatment sludge), well-controlled incubation experiments were conducted using a 2-factor factorial design with six temperatures (22, 29, 36, 43, 50, and 57 degrees C) and five moisture contents (30, 40, 50, 60, and 70%). The microbial activity was measured as O2 uptake rate (mg g(-1) h(-1)) using a computer controlled respirometer. In this study, moisture content proved to be a dominant factor impacting aerobic microbial activity of the composting blend. Fifty percent moisture content appeared to be the minimal requirement for obtaining activities greater than 1.0 mg g(-1) h(-1). Temperature was also documented to be an important factor for biosolids composting. However, its effect was less influential than moisture content. Particularly, the enhancement of composting activities induced by temperature increment could be realized by increasing moisture content alone.

  7. Factors controlling black carbon distribution in the Arctic

    Science.gov (United States)

    Qi, Ling; Li, Qinbin; Li, Yinrui; He, Cenlin

    2017-01-01

    We investigate the sensitivity of black carbon (BC) in the Arctic, including BC concentration in snow (BCsnow, ng g-1) and surface air (BCair, ng m-3), as well as emissions, dry deposition, and wet scavenging using the global three-dimensional (3-D) chemical transport model (CTM) GEOS-Chem. We find that the model underestimates BCsnow in the Arctic by 40 % on average (median = 11.8 ng g-1). Natural gas flaring substantially increases total BC emissions in the Arctic (by ˜ 70 %). The flaring emissions lead to up to 49 % increases (0.1-8.5 ng g-1) in Arctic BCsnow, dramatically improving model comparison with observations (50 % reduction in discrepancy) near flaring source regions (the western side of the extreme north of Russia). Ample observations suggest that BC dry deposition velocities over snow and ice in current CTMs (0.03 cm s-1 in the GEOS-Chem) are too small. We apply the resistance-in-series method to compute a dry deposition velocity (vd) that varies with local meteorological and surface conditions. The resulting velocity is significantly larger and varies by a factor of 8 in the Arctic (0.03-0.24 cm s-1), which increases the fraction of dry to total BC deposition (16 to 25 %) yet leaves the total BC deposition and BCsnow in the Arctic unchanged. This is largely explained by the offsetting higher dry and lower wet deposition fluxes. Additionally, we account for the effect of the Wegener-Bergeron-Findeisen (WBF) process in mixed-phase clouds, which releases BC particles from condensed phases (water drops and ice crystals) back to the interstitial air and thereby substantially reduces the scavenging efficiency of clouds for BC (by 43-76 % in the Arctic). The resulting BCsnow is up to 80 % higher, BC loading is considerably larger (from 0.25 to 0.43 mg m-2), and BC lifetime is markedly prolonged (from 9 to 16 days) in the Arctic. Overall, flaring emissions increase BCair in the Arctic (by ˜ 20 ng m-3), the updated vd more than halves BCair (by ˜ 20 ng m-3

  8. Transcription factor control of growth rate dependent genes in Saccharomyces cerevisiae: A three factor design

    DEFF Research Database (Denmark)

    Fazio, Alessandro; Jewett, Michael Christopher; Daran-Lapujade, Pascale

    2008-01-01

    , such as Ace2 and Swi6, and stress response regulators, such as Yap1, were also shown to have significantly enriched target sets. Conclusion: Our work, which is the first genome-wide gene expression study to investigate specific growth rate and consider the impact of oxygen availability, provides a more......Background: Characterization of cellular growth is central to understanding living systems. Here, we applied a three-factor design to study the relationship between specific growth rate and genome-wide gene expression in 36 steady-state chemostat cultures of Saccharomyces cerevisiae. The three...... factors we considered were specific growth rate, nutrient limitation, and oxygen availability. Results: We identified 268 growth rate dependent genes, independent of nutrient limitation and oxygen availability. The transcriptional response was used to identify key areas in metabolism around which m...

  9. Factors controlling the engraftment of transplanted dog bone marrow cells

    International Nuclear Information System (INIS)

    Vriesendorp, H.M.; Klapwyk, W.M.; Heidt, P.J.; Hogeweg, B.; Zurcher, C.; Bekkum, D.W. van

    1982-01-01

    The LD50 of total body irradiation (TBI) for the bone marrow (BM) syndrome and the gastrointestinal (GI) syndrme was determined in dogs as 3.7 Gy, and 8.5 Gy respectively. Five Gy TBI was adequate conditioning for BM cells of littermate donors identical for the major histocompatibility comples (MHC). The maximum tolerated TBI (about 7.5 Gy) caused more side effects than 5.0 Gy TBI and was insufficient for engraftment of realistic numbers of BM cells of MHC mismatched donors. In autologous and MHC matched transplants, the rateof hemopoietic recovery correlated with the number of BM cells given. Approximtely 2 x 10 7 autologous and 1 x 10 8 MHC identical BM cells.kg -1 were needed for radiation protection. Platelet recovery was significantly more rapid in allogeneic combinations in comparison to autologous transplants. Low numbers of autologous cryopreserved bone marrow cells were as effective as fresh bone marrow cells in rescuing animals after lethal TBI. Other factors that influence BM cell engraftment were confirmed (prior sensitization of the recipient, donor selection) or identified (purification of BM cells on density gradient and selective gastrointestinal decontamination of the recipient). Consistent engraftment of gradient separated, MHC identical, BM cells was found after conditioning with two fractions of 6.0 Gy TBI, separated by 72 h. One MHC haplotype mismatched marrow did engraft after two TBI fractions of 6.0 Gy. Engraftment no longer occurred with gradient purified bone marrow cells from this type of donor. Late effects of TBI were early greying in all animals, and secondary uterine inertia in female dogs after 7.5 GY TBI. Fertility in males or females was not changed by radiation. An increase of pancreas fibrosis was noted in dogs receiving fractions of 6.0 Gy TBI. (author)

  10. Factors controlling stable isotope composition of European precipitation

    International Nuclear Information System (INIS)

    Rozanski, K.; Sonntag, C.; Muennich, K.O.

    1982-01-01

    The seasonal and spatial variations of stable isotope ratios in present day European precipitation are simulated with a simple multibox model of the mean west-east horizontal transport of the atmospheric water vapour across the European continent. Isotope fractionation during the formation of precipitation leads to an increasing depletion of heavy isotopes in the residual air moisture as it moves towards the centre of the continent. This isotopic depletion is partly compensated, particularly in summer, by evapotranspiration, which is assumed to transfer soil water into the atmosphere without isotope fractionation. The model estimates are based on horizontal water vapour flux data, varying seasonally between 88 and 130 kg m -1 s -1 for the Atlantic coast region, and on the monthly precipitation, evapotranspiration and surface air temperature data available for various locations in Europe. Both continental and seasonal temperature effects observed in the stable isotope composition of European precipitation are fairly well reproduced by the model. The calculations show that the isotopic composition of local precipitation is primarily controlled by regional scale processes, i.e. by the water vapour transport patterns into the continent, and by the average precipitation-evapotranspiration history of the air masses precipitating at a given place. Local parameters such as the surface and/or cloud base temperature or the amount of precipitation modify the isotope ratios only slightly. Implications of the model predictions for the interpretation of stable isotope ratios in earlier periods as they are preserved in ice cores and in groundwater are also discussed. (Auth.)

  11. ERAD-dependent control of the Wnt secretory factor Evi.

    Science.gov (United States)

    Glaeser, Kathrin; Urban, Manuela; Fenech, Emma; Voloshanenko, Oksana; Kranz, Dominique; Lari, Federica; Christianson, John C; Boutros, Michael

    2018-02-15

    Active regulation of protein abundance is an essential strategy to modulate cellular signaling pathways. Within the Wnt signaling cascade, regulated degradation of β-catenin by the ubiquitin-proteasome system (UPS) affects the outcome of canonical Wnt signaling. Here, we found that abundance of the Wnt cargo receptor Evi (Wls/GPR177), which is required for Wnt protein secretion, is also regulated by the UPS through endoplasmic reticulum (ER)-associated degradation (ERAD). In the absence of Wnt ligands, Evi is ubiquitinated and targeted for ERAD in a VCP-dependent manner. Ubiquitination of Evi involves the E2-conjugating enzyme UBE2J2 and the E3-ligase CGRRF1. Furthermore, we show that a triaging complex of Porcn and VCP determines whether Evi enters the secretory or the ERAD pathway. In this way, ERAD-dependent control of Evi availability impacts the scale of Wnt protein secretion by adjusting the amount of Evi to meet the requirement of Wnt protein export. As Wnt and Evi protein levels are often dysregulated in cancer, targeting regulatory ERAD components might be a useful approach for therapeutic interventions. © 2018 The Authors. Published under the terms of the CC BY 4.0 license.

  12. Dual RNA regulatory control of a Staphylococcus aureus virulence factor.

    Science.gov (United States)

    Chabelskaya, Svetlana; Bordeau, Valérie; Felden, Brice

    2014-04-01

    In pathogens, the accurate programming of virulence gene expression is essential for infection. It is achieved by sophisticated arrays of regulatory proteins and ribonucleic acids (sRNAs), but in many cases their contributions and connections are not yet known. Based on genetic, biochemical and structural evidence, we report that the expression pattern of a Staphylococcus aureus host immune evasion protein is enabled by the collaborative actions of RNAIII and small pathogenicity island RNA D (SprD). Their combined expression profiles during bacterial growth permit early and transient synthesis of Sbi to avoid host immune responses. Together, these two sRNAs use antisense mechanisms to monitor Sbi expression at the translational level. Deletion analysis combined with structural analysis of RNAIII in complex with its novel messenger RNA (mRNA) target indicate that three distant RNAIII domains interact with distinct sites of the sbi mRNA and that two locations are deep in the sbi coding region. Through distinct domains, RNAIII lowers production of two proteins required for avoiding innate host immunity, staphylococcal protein A and Sbi. Toeprints and in vivo mutational analysis reveal a novel regulatory module within RNAIII essential for attenuation of Sbi translation. The sophisticated translational control of mRNA by two differentially expressed sRNAs ensures supervision of host immune escape by a major pathogen.

  13. Evaluation of cooling water treatment programme at RAPS-3 and 4 with reference to chlorination and microbial control

    International Nuclear Information System (INIS)

    Kora, Aruna Jyothi; Rao, T.S.; Narasimhan, S.V.

    2008-01-01

    Water from Rana Pratap Sagar Lake is used in Rajasthan Atomic Power Station (RAPS) units 3 and 4 for cooling the condenser system. As the lake water is rich in nutrients and microflora, investigations were carried out on the nutrient quality, microflora distribution and chlorine decay to evaluate the cooling water treatment programme. Algal growth in emergency storage makeup water pools, weed growth on the cooling tower decks and biofilm growth on various materials (carbon steel, stainless steel, admiralty brass and cupronickel) were studied with an objective to understand the reasons for corrosion and failure of fire water pipeline. Visual examination showed that the emergency makeup water pools were infested with green algae and cyano-bacterial mats. Some algal growth was observed on induced draft cooling tower-3 structures. The bacterial counts in various water samples were low, except in emergency makeup water pool. Sulphate reducing bacteria (SRB) were present in makeup and demineralised waters. Chlorophyll pigment analysis showed that the makeup and emergency storage water pool had abundant algal growth. To prevent biofouling, chlorine is dosed at the rate of 7 kg/hr for 10 minutes; free residual oxidant (FRO) and chlorine decay were monitored at regular intervals. After 24 hrs, biofilm thickness on different materials ranged from 27-45 μm. However, the thickness was reduced by 50 % after exposure to 2 ppm of chlorine for 15 minutes. In further investigations, it was found that the anion resin beads of demineraliser plant were infested with filamentous microbes. Hence, It is recommended to treat the feed water of DM plant. Tubercles were observed inside the failed fire water carbon steel pipeline and on removing the tubercles concentric ring patterns, typical signatures of SRB corrosion were observed. For controlling the biofouling problem in the cooling water system, it is recommended to maintain a chlorine dose of 2.3 ppm (which gives 0.8 ppm FRO) for two

  14. Research on Open-Closed-Loop Iterative Learning Control with Variable Forgetting Factor of Mobile Robots

    Directory of Open Access Journals (Sweden)

    Hongbin Wang

    2016-01-01

    Full Text Available We propose an iterative learning control algorithm (ILC that is developed using a variable forgetting factor to control a mobile robot. The proposed algorithm can be categorized as an open-closed-loop iterative learning control, which produces control instructions by using both previous and current data. However, introducing a variable forgetting factor can weaken the former control output and its variance in the control law while strengthening the robustness of the iterative learning control. If it is applied to the mobile robot, this will reduce position errors in robot trajectory tracking control effectively. In this work, we show that the proposed algorithm guarantees tracking error bound convergence to a small neighborhood of the origin under the condition of state disturbances, output measurement noises, and fluctuation of system dynamics. By using simulation, we demonstrate that the controller is effective in realizing the prefect tracking.

  15. Tales of two self-control scales: Relations with Five-Factor and HEXACO traits

    NARCIS (Netherlands)

    de Vries, R.E.; van Gelder, J.L.

    2013-01-01

    This study compared the Five-Factor and HEXACO personality correlates of two common self-control constructs - Tangney self-control and Grasmick self-control - and their relations with delinquency. In both a student and a community sample, conscientiousness (mainly the prudence facet) was the most

  16. 75 FR 69912 - Pipeline Safety: Control Room Management/Human Factors

    Science.gov (United States)

    2010-11-16

    ... 192 and 195 [Docket ID PHMSA-2007-27954] RIN 2137-AE64 Pipeline Safety: Control Room Management/Human... Control Room Management/Human Factors rule at 49 CFR 192.631 and 195.446. The NPRM proposes to expedite... rule and to engage in open discussions with the agency at PHMSA's Control Room Management...

  17. Psychosocial and Psychiatric Factors Associated with Adolescent Suicide: A Case-Control Psychological Autopsy Study

    Science.gov (United States)

    Portzky, Gwendolyn; Audenaert, Kurt; van Heeringen, Kees

    2009-01-01

    This study aimed at the investigation of psychosocial and psychiatric risk factors of adolescent suicide by means of a case-control psychological autopsy study. Relatives and other informants of 19 suicide victims and 19 matched psychiatric controls were interviewed by means of a semi-structured interview schedule. Psychiatric controls included…

  18. ENGINEERING AND ECONOMIC FACTORS AFFECTING THE INSTALLATION OF CONTROL TECHNOLOGIES FOR MULTIPOLLUTANT STRATEGIES

    Science.gov (United States)

    The report evaluates the engineering and economic factors associated with installing air pollution control technologies to meet the requirements of strategies to control sulfur dioxide (SO2), oxides of nitrogen (NOX), and mercury under the Clear Skies Act multipollutant control s...

  19. Yardang geometries in the Qaidam Basin and their controlling factors

    Science.gov (United States)

    Hu, Chengqing; Chen, Ninghua; Kapp, Paul; Chen, Jianyu; Xiao, Ancheng; Zhao, Yanhui

    2017-12-01

    The hyperarid Qaidam Basin features extensive fields of yardangs (covering an area of 40,000km2) sculpted in tectonically folded sedimentary rocks. We extracted the geometries of 16,749 yardangs, such as length-to-width ratio (L/W), spatial density, and spacing, from multi-source remote sensing data provided by Google Earth™. We classified the yardangs into four types based on their L/W: short-axis (1-2), whale-back (2-6), hogsback (6-10) and long-ridge (10 - 210). We interpreted the yardang geometries in the context of their geologic setting (bedding orientation, location along anticline crests or syncline troughs, and lithologic heterogeneity). Our results show that the yardang geometries in the Qaidam Basin are mainly controlled by the structural geology and rheology of the sedimentary rocks (e.g., strike and dip of bedding, the presence or absence of interbedded soft and hard beds, and structural position with folds), the angle between geomorphically-effective wind directions and the strike of bedding, and the relative cumulative wind shear force where two geomorphically-effective wind directions are present. Our analysis revealed the following: 1) nearly 69% of the yardangs with long-ridge and hogsback geometries are distributed in syncline areas whereas 73% of the yardangs with short-axis geometries are distributed in anticline areas; 2) the L/W ratio of yardangs exposed along the windward limbs of anticlines is lower than that of yardangs exposed along the leeward limbs; and 3) in the westernmost parts of the basin, yardangs are locally sculpted into mounds by two geomorphically-effective wind directions.

  20. Photodegradation processes in arid ecosystems: controlling factors and potential application in land restoration

    Science.gov (United States)

    Muñoz-Rojas, Miriam; Luna-Ramos, Lourdes; Oyonarte, Cecilio; Sole Benet, Albert

    2017-04-01

    Water availability plays a fundamental part in controlling biotic processes in arid ecosystems. However, recent evidence suggests that other decisive drivers take part in these processes. Despite low annual rainfall and microbial activity, unexplained high rates of litter decomposition, net nitrogen mineralization, soil enzymatic activity and carbon turnover have been observed in arid ecosystems. These observations have been partly explained by photodegradation, a process that consists of the breakdown of organic matter via solar radiation (UV) and that can increase decomposition rates and lead to changes in the balance of carbon and nutrients between plants, soil and atmosphere. A complete understanding of these mechanisms and its drivers in arid ecosystems remains a critical challenge for the scientific community at the global level. In this research, we conducted a multi-site field experiment to test the effects of photodegradation on decomposition of organic amendments used in ecosystem restoration. The study was carried out during 12 months in two study areas: the Pilbara region in Western Australia (Southern Hemisphere) and the Cabo de Gata Nijar Natural Park, South Spain (Northern Hemisphere). In both sites, four treatments were applied in replicated plots (1x1 m, n=4) that included a control (C) with no soil amendment; organic amendment covering the soil surface (AS); organic amendment incorporated into the soil (AI); and a combination of both techniques, both covering the surface and incorporated into the soil (AS-AI). Different organic amendments (native mulch versus compost) and soil substrates were used at each site according to local practices, but in both sites these were applied to increase soil organic matter up to 2%. At the two locations, a radiometer and a logger with a soil temperature and soil moisture probe were installed to monitor UV radiation and soil conditions for the duration of the trial. Soil microbial activity, soil CO2 efflux, and

  1. Impact of warm winters on microbial growth

    Science.gov (United States)

    Birgander, Johanna; Rousk, Johannes; Axel Olsson, Pål

    2014-05-01

    temperature relationships of the bacterial community from winter-warmed plots and plots with ambient soil temperatures were compared. No change in optimum temperature for growth could be detected, indicating that the microbial community has not been warm-adapted. This fits with what was seen also in the laboratory experiment where no changes in temperature response occurred when exposing bacteria to temperatures below 10 °C within two months. The increase in activity measured during winter should thereby be due to changes in environmental factors, which will be further investigated. One big difference between heated and control plots was that heated plots were snow free during the entire winter, while control plots were covered by a 10 cm snow cover. The plant community composition and flowering time also differed in the warmed and ambient plot.

  2. Procedures For Microbial-Ecology Laboratory

    Science.gov (United States)

    Huff, Timothy L.

    1993-01-01

    Microbial Ecology Laboratory Procedures Manual provides concise and well-defined instructions on routine technical procedures to be followed in microbiological laboratory to ensure safety, analytical control, and validity of results.

  3. Microbial Life of North Pacific Oceanic Crust

    Science.gov (United States)

    Schumann, G.; Koos, R.; Manz, W.; Reitner, J.

    2003-12-01

    Information on the microbiology of the deep subsurface is necessary in order to understand the factors controlling the rate and extent of the microbially catalyzed reactions that influence the geophysical properties of these environments. Drilling into 45-Ma oceanic basaltic crust in a deepwater environment during ODP Leg 200 provided a promising opportunity to explore the abundance, diversity and activity of micro-organisms. The combined use of culture-independent molecular phylogenetic analyses and enrichment culture techniques is an advantageous approach in investigating subsurface microbial ecosystems. Enrichment culture methods allow the evaluation of potential activities and functions. Microbiological investigations revealed few aerobic cultivable, in part hitherto unknown, micro-organisms in deep submarine sediments and basaltic lava flows. 16S rDNA sequencing of isolates from sediment revealed the next relatives to be members of the genera Halomonas, Pseudomonas, and Lactobacillus. Within the Pseudomonadaceae the closest relative is Acinetobacter sp., which was isolated from a deep subsurface environment. The next phylogenetical relatives within the Halomonadaceae are bacteria typically isolated from Soda lakes, which are considered as model of early life conditions. Interestingly, not only sediment bacteria could be obtained in pure culture. Aerobic strains could also be successfully isolated from the massive tholeiitic basalt layer at a depth of 76.16 mbsf (46 m below the sediment/basement contact). These particular isolates are gram-positive with low G+C content of DNA, phylogenetically affiliated to the phylum Firmicutes. The closest neighbors are e.g. a marine Bacillus isolated from the Gulf of Mexico and a low G+C gram-positive bacterium, which belongs to the microbial flora in the deepest sea mud of the Mariana Trench, isolated from a depth of 10,897 m. Based on the similarity values, the isolates represent hitherto undescribed species of the deep

  4. Proportional-Integral-Derivative (PID) Control of Secreted Factors for Blood Stem Cell Culture.

    Science.gov (United States)

    Caldwell, Julia; Wang, Weijia; Zandstra, Peter W

    2015-01-01

    Clinical use of umbilical cord blood has typically been limited by the need to expand hematopoietic stem and progenitor cells (HSPC) ex vivo. This expansion is challenging due to the accumulation of secreted signaling factors in the culture that have a negative regulatory effect on HSPC output. Strategies for global regulation of these factors through dilution have been developed, but do not accommodate the dynamic nature or inherent variability of hematopoietic cell culture. We have developed a mathematical model to simulate the impact of feedback control on in vitro hematopoiesis, and used it to design a proportional-integral-derivative (PID) control algorithm. This algorithm was implemented with a fed-batch bioreactor to regulate the concentrations of secreted factors. Controlling the concentration of a key target factor, TGF-β1, through dilution limited the negative effect it had on HSPCs, and allowed global control of other similarly-produced inhibitory endogenous factors. The PID control algorithm effectively maintained the target soluble factor at the target concentration. We show that feedback controlled dilution is predicted to be a more cost effective dilution strategy compared to other open-loop strategies, and can enhance HSPC expansion in short term culture. This study demonstrates the utility of secreted factor process control strategies to optimize stem cell culture systems, and motivates the development of multi-analyte protein sensors to automate the manufacturing of cell therapies.

  5. 11 Soil Microbial Biomass

    African Journals Online (AJOL)

    186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

  6. Molecular microbial ecology manual

    NARCIS (Netherlands)

    Kowalchuk, G.A.; Bruijn, de F.J.; Head, I.M.; Akkermans, A.D.L.

    2004-01-01

    The field of microbial ecology has been revolutionized in the past two decades by the introduction of molecular methods into the toolbox of the microbial ecologist. This molecular arsenal has helped to unveil the enormity of microbial diversity across the breadth of the earth's ecosystems, and has

  7. Microbial Rechargeable Battery

    NARCIS (Netherlands)

    Molenaar, Sam D.; Mol, Annemerel R.; Sleutels, Tom H.J.A.; Heijne, Ter Annemiek; Buisman, Cees J.N.

    2016-01-01

    Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial

  8. Discussion on verification criterion and method of human factors engineering for nuclear power plant controller

    International Nuclear Information System (INIS)

    Yang Hualong; Liu Yanzi; Jia Ming; Huang Weijun

    2014-01-01

    In order to prevent or reduce human error and ensure the safe operation of nuclear power plants, control device should be verified from the perspective of human factors engineering (HFE). The domestic and international human factors engineering guidelines about nuclear power plant controller were considered, the verification criterion and method of human factors engineering for nuclear power plant controller were discussed and the application examples were provided for reference in this paper. The results show that the appropriate verification criterion and method should be selected to ensure the objectivity and accuracy of the conclusion. (authors)

  9. Urinary Tract Infections Among Hospitalized Adults in the Early Post-Liver Transplant Period: Prevalence, Risk Factors, Causative Agents, and Microbial Susceptibility.

    Science.gov (United States)

    Pouladfar, Gholamreza; Jafarpour, Zahra; Firoozifar, Mohammad; Malek Hosseini, Seyed Ali; Rasekh, Razieh; Khosravifard, Leila; Janghorban, Parisa

    2017-02-01

    Urinary tract infections are among the most common infections after liver transplant, especially soon after surgery. This study analyzed urinary tract infections or bacteriuria, their causative agents, and related risk factors in the early period after liver transplant in hospitalized adult transplant recipients in the main liver transplant referral center in Iran. In this prospective study, 389 consecutive adult patients who underwent liver transplant at the Nemazee Teaching Hospital were enrolled between October 2014 and October 2015. Risk factors were compared for patients who developed urinary tract infections or bacteriuria ("infection group "; n = 63 [16.2% ]) and patients without evidence of infection ("control group "; n = 211 [54.2% ]). Patients with sites of infection other than the urinary tract were excluded. Antimicrobial sus ceptibility testing was performed using the Kirby-Bauer disk-diffusion method. Univariate and multivariate analyses compared variables between the 2 groups. Seventy-nine episodes of urinary tract infections or bacteriuria occurred in the infection group. Multiple logistic regression analysis showed that female sex, hospitalization 2 to 7 days before transplant, and frequency of abdominal exploration were 11.0, 5.9, and 3.0 times more common in the infection group than in the control group. The chance of infection rises 1.1 times with each one unit increase of body mass index. The most common infection causes were gram-negative bacteria (n = 50; 63.3%), predominantly Escherichia coli (n = 24; 30.4%); followed by gram-positive bacteria (n = 20; 25.3%), predominantly Enterococcus species (n = 14; 17.8%) that had a high incidence of vancomycin resistance (n = 10; 71.4%); and non-Candida albicans species isolates (n = 9; 11.4%). Urinary tract infections are a common infection in hospitalized adult patients soon after liver transplant. Female sex, hospitalization shortly before transplant, more frequent abdominal exploration, and higher

  10. Analysis on nuclear power plant control room system design and improvement based on human factor engineering

    International Nuclear Information System (INIS)

    Gao Feng; Liu Yanzi; Sun Yongbin

    2014-01-01

    The design of nuclear power plant control room system is a process of improvement with the implementation of human factor engineering theory and guidance. The method of implementation human factor engineering principles into the nuclear power plant control room system design and improvement was discussed in this paper. It is recommended that comprehensive address should be done from control room system function, human machine interface, digital procedure, control room layout and environment design based on the human factor engineering theory and experience. The main issues which should be paid more attention during the control room system design and improvement also were addressed in this paper, and then advices and notices for the design and improvement of the nuclear power plant control room system were afforded. (authors)

  11. Microbial biofilms: biosurfactants as antibiofilm agents.

    Science.gov (United States)

    Banat, Ibrahim M; De Rienzo, Mayri A Díaz; Quinn, Gerry A

    2014-12-01

    Current microbial inhibition strategies based on planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilm communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. All aspects of biofilm measurement, monitoring, dispersal, control, and inhibition are becoming issues of increasing importance. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms in addition to many other advantages. The dispersal properties of biosurfactants have been shown to rival those of conventional inhibitory agents against bacterial and yeast biofilms. This makes them suitable candidates for use in new generations of microbial dispersal agents and for use as adjuvants for existing microbial suppression or eradication strategies. In this review, we explore aspects of biofilm characteristics and examine the contribution of biologically derived surface-active agents (biosurfactants) to the disruption or inhibition of microbial biofilms.

  12. Temperature sensitivity of soil respiration rates enhanced by microbial community response.

    Science.gov (United States)

    Karhu, Kristiina; Auffret, Marc D; Dungait, Jennifer A J; Hopkins, David W; Prosser, James I; Singh, Brajesh K; Subke, Jens-Arne; Wookey, Philip A; Agren, Göran I; Sebastià, Maria-Teresa; Gouriveau, Fabrice; Bergkvist, Göran; Meir, Patrick; Nottingham, Andrew T; Salinas, Norma; Hartley, Iain P

    2014-09-04

    Soils store about four times as much carbon as plant biomass, and soil microbial respiration releases about 60 petagrams of carbon per year to the atmosphere as carbon dioxide. Short-term experiments have shown that soil microbial respiration increases exponentially with temperature. This information has been incorporated into soil carbon and Earth-system models, which suggest that warming-induced increases in carbon dioxide release from soils represent an important positive feedback loop that could influence twenty-first-century climate change. The magnitude of this feedback remains uncertain, however, not least because the response of soil microbial communities to changing temperatures has the potential to either decrease or increase warming-induced carbon losses substantially. Here we collect soils from different ecosystems along a climate gradient from the Arctic to the Amazon and investigate how microbial community-level responses control the temperature sensitivity of soil respiration. We find that the microbial community-level response more often enhances than reduces the mid- to long-term (90 days) temperature sensitivity of respiration. Furthermore, the strongest enhancing responses were observed in soils with high carbon-to-nitrogen ratios and in soils from cold climatic regions. After 90 days, microbial community responses increased the temperature sensitivity of respiration in high-latitude soils by a factor of 1.4 compared to the instantaneous temperature response. This suggests that the substantial carbon stores in Arctic and boreal soils could be more vulnerable to climate warming than currently predicted.

  13. Performance evaluation of nanoclay enriched anti-microbial hydrogels for biomedical applications

    Directory of Open Access Journals (Sweden)

    Sonali Karnik

    2016-02-01

    Full Text Available A major factor contributing to the failure of orthopedic and orthodontic implants is post-surgical infection. Coating metallic implant surfaces with anti-microbial agents has shown promise but does not always prevent the formation of bacterial biofilms. Furthermore, breakdown of these coatings within the human body can cause release of the anti-microbial drugs in an uncontrolled or unpredictable fashion. In this study, we used a calcium alginate and calcium phosphate cement (CPC hydrogel composite as the base material and enriched these hydrogels with the anti-microbial drug, gentamicin sulfate, loaded within a halloysite nanotubes (HNTs. Our results demonstrate a sustained and extended release of gentamicin from hydrogels enriched with the gentamicin-loaded HNTs. When tested against the gram-negative bacteria, the hydrogel/nanoclay composites showed a pronounced zone of inhibition suggesting that anti-microbial doped nanoclay enriched hydrogels can prevent the growth of bacteria. The release of gentamicin sulfate for a period of five days from the nanoclay-enriched hydrogels would supply anti-microbial agents in a sustained and controlled manner and assist in preventing microbial growth and biofilm formation on the titanium implant surface. A pilot study, using mouse osteoblasts, confirmed that the nanoclay enriched surfaces are also cell supportive as osteoblasts readily, proliferated and produced a type I collagen and proteoglycan matrix.

  14. Key players and team play: anaerobic microbial communities in hydrocarbon-contaminated aquifers.

    Science.gov (United States)

    Kleinsteuber, Sabine; Schleinitz, Kathleen M; Vogt, Carsten

    2012-05-01

    Biodegradation of anthropogenic pollutants in shallow aquifers is an important microbial ecosystem service which is mainly brought about by indigenous anaerobic microorganisms. For the management of contaminated sites, risk assessment and control of natural attenuation, the assessment of in situ biodegradation and the underlying microbial processes is essential. The development of novel molecular methods, "omics" approaches, and high-throughput techniques has revealed new insight into complex microbial communities and their functions in anoxic environmental systems. This review summarizes recent advances in the application of molecular methods to study anaerobic microbial communities in contaminated terrestrial subsurface ecosystems. We focus on current approaches to analyze composition, dynamics, and functional diversity of subsurface communities, to link identity to activity and metabolic function, and to identify the ecophysiological role of not yet cultured microbes and syntrophic consortia. We discuss recent molecular surveys of contaminated sites from an ecological viewpoint regarding degrader ecotypes, abiotic factors shaping anaerobic communities, and biotic interactions underpinning the importance of microbial cooperation for microbial ecosystem services such as contaminant degradation.

  15. Molecular- and cultivation-based analyses of microbial communities in oil field water and in microcosms amended with nitrate to control H{sub 2}S production

    Energy Technology Data Exchange (ETDEWEB)

    Kumaraswamy, Raji; Ebert, Sara; Fedorak, Phillip M.; Foght, Julia M. [Alberta Univ., Edmonton, AB (Canada). Biological Sciences; Gray, Murray R. [Alberta Univ., Edmonton, AB (Canada). Chemical and Materials Engineering

    2011-03-15

    Nitrate injection into oil fields is an alternative to biocide addition for controlling sulfide production ('souring') caused by sulfate-reducing bacteria (SRB). This study examined the suitability of several cultivation-dependent and cultivation-independent methods to assess potential microbial activities (sulfidogenesis and nitrate reduction) and the impact of nitrate amendment on oil field microbiota. Microcosms containing produced waters from two Western Canadian oil fields exhibited sulfidogenesis that was inhibited by nitrate amendment. Most probable number (MPN) and fluorescent in situ hybridization (FISH) analyses of uncultivated produced waters showed low cell numbers ({<=}10{sup 3} MPN/ml) dominated by SRB (>95% relative abundance). MPN analysis also detected nitrate-reducing sulfide-oxidizing bacteria (NRSOB) and heterotrophic nitrate-reducing bacteria (HNRB) at numbers too low to be detected by FISH or denaturing gradient gel electrophoresis (DGGE). In microcosms containing produced water fortified with sulfate, near-stoichiometric concentrations of sulfide were produced. FISH analyses of the microcosms after 55 days of incubation revealed that Gammaproteobacteria increased from undetectable levels to 5-20% abundance, resulting in a decreased proportion of Deltaproteobacteria (50-60% abundance). DGGE analysis confirmed the presence of Delta- and Gammaproteobacteria and also detected Bacteroidetes. When sulfate-fortified produced waters were amended with nitrate, sulfidogenesis was inhibited and Deltaproteobacteria decreased to levels undetectable by FISH, with a concomitant increase in Gammaproteobacteria from below detection to 50-60% abundance. DGGE analysis of these microcosms yielded sequences of Gamma- and Epsilonproteobacteria related to presumptive HNRB and NRSOB (Halomonas, Marinobacterium, Marinobacter, Pseudomonas and Arcobacter), thus supporting chemical data indicating that nitrate-reducing bacteria out-compete SRB when nitrate is

  16. Visual control as a key factor in a production process of a company from automotive branch

    Directory of Open Access Journals (Sweden)

    Stanisław Borkowski

    2013-04-01

    Full Text Available This article presents a theoretical basis for one type of control in enterprises – visual control. It presents the meaning of visual control in the Toyota Production System and BOST researches as a tool of measure, among other things, the importance of visual control in production companies. The level of importance of visual control usage as one of the production process elements in the analysed company was indicated. The usage of visual control is a main factor in a production process of the analyzed company, the factor which provides continuous help to employees to check whether the process differs from the standard. The characteristic progression of production process elements was indicated and the SW factor (the use of visual control took the third place, PE factor (interruption of production when it detects a problem of quality turned out to be the most important one, while the least important was the EU factor (granting power of attorney down. The main tools for this evaluation: an innovative BOST survey - Toyota's management principles in questions, in particular, the Pareto-Lorenz diagram, radar graph and series of importance as graphical interpretation tools, were used to present the importance of each factor in relation to individual assessments.

  17. Identification of key factors in Accelerated Low Water Corrosion through experimental simulation of tidal conditions: influence of stimulated indigenous microbiota

    NARCIS (Netherlands)

    Marty, F.; Gueuné, H.; Malard, E.; Sánchez-Amaya, J.M.; Sjögren, L.; Abbas, B.; Quillet, L.; van Loosdrecht, M.C.M.; Muyzer, G.

    2014-01-01

    Biotic and abiotic factors favoring Accelerated Low Water Corrosion (ALWC) on harbor steel structures remain unclear warranting their study under controlled experimental tidal conditions. Initial stimulation of marine microbial consortia by a pulse of organic matter resulted in localized corrosion

  18. Integrated application of human factors to a power plant control room information system

    International Nuclear Information System (INIS)

    Fish, H.C. Jr.; Gutierrez, R.

    1988-01-01

    The human factors plan was developed as a methodology to apply human factors from the conceptual design of the EPIC system to the functional verification conducted at the plant. An integral part of the Human Factors Plan was the Functional Verification Plan. Developed in parallel, this second plan and its resultant programs verified functional appropriateness of the SPDS display, NSSS displays, EOP displays, man-machine interfaces (MMI), and workstation designs. The functional verification process was performed at the hardware/software developer's factory and at the JAFNPP, following installation of the EPIC system. Because the EPIC system replaces existing control room equipment, it is important that human factors be applied in a systematic manner consistent with other control room displays and controls. To ensure that this goal was met, a human factors plan was developed

  19. Modeling and Control of DC/DC Boost Converter using K-Factor Control for MPPT of Solar PV System

    DEFF Research Database (Denmark)

    Vangari, Adithya; Haribabu, Divyanagalakshmi; Sakamuri, Jayachandra N.

    2015-01-01

    This paper is focused on the design of a controller for the DC/DC boost converter using K factor control, which is based on modified PI control method, for maximum power point tracking (MPPT) of solar PV system. A mathematical model for boost converter based on small signal averaging approach...... is presented. Design of the passive elements of the boost converter as per the system specifications is also illustrated. The performance of the proposed K factor control method is verified with the simulations for MPPT on solar PV system at different atmospheric conditions. A new circuit based model for solar...... PV array, which includes the effect of solar insolation and temperature on PV array output, for the application in power system transient simulations, is also presented. The performance of the PV array model is verified with simulations at different atmospheric conditions. A 160W PV module from BP...

  20. 75 FR 5536 - Pipeline Safety: Control Room Management/Human Factors, Correction

    Science.gov (United States)

    2010-02-03

    ... DEPARTMENT OF TRANSPORTATION Pipeline and Hazardous Materials Safety Administration 49 CFR Parts...: Control Room Management/Human Factors, Correction AGENCY: Pipeline and Hazardous Materials Safety... following correcting amendments: PART 192--TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM...

  1. Human-factors engineering-control-room design review: Shoreham Nuclear Power Station. Draft audit report

    International Nuclear Information System (INIS)

    Peterson, L.R.; Preston-Smith, J.; Savage, J.W.; Rousseau, W.F.

    1981-01-01

    A human factors engineering preliminary design review of the Shoreham control room was performed at the site on March 30 through April 3, 1981. This design review was carried out by a team from the Human Factors Engineering Branch, Division of Human Factors Safety. This report was prepared on the basis of the HFEB's review of the applicant's Preliminary Design Assessment and the human factors engineering design review/audit performed at the site. The presented sections are numbered to conform to the guidelines of the draft version of NUREG-0700. They summarize the teams's observations of the control room design and layout, and of the control room operators' interface with the control room environment

  2. Evaluation on the Effect of Load Follow Controller's Weighting Factors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Keuk Jong; Lee, Jae Gon [KHNP CRI, Daejeon (Korea, Republic of)

    2016-10-15

    there are several important physical effects that limit the possibilities of power variations in NPPs. Some major effects are moderator and xenon effect. Moderator effect is relation with moderator density change and xenon effect is relation with the concentration change of Xe-135 which could affect axial power shape. These effects are more significant with large magnitudes of power variations and they are considered as major disturbances at the aspect of control method. Due to the above physical effects, it is necessary to carefully change nuclear power considering power distribution change in the core. So, when nuclear plants are required to operate on load variation mode, we could control not only reactor power but also power distribution. Generally, power distribution is controlled by reactor operators who have enough experience, whereas reactor power is automatically controlled by automatic controllers. So, it is necessary to design an automatic controller that controls both reactor power and power distribution for frequent load following operation. Korea Hydro and Nuclear Power Co., LTD (KHNP) has been developing automatic load follow controller as a part of Advanced Power Reactor Plus (APR+) development. The developing controller is composed of three algorithms which could control reactor power and axial power shape. This paper aimed to evaluate the effect of the controller’s weighting factors. So, in this paper, we identify the meaning of the weighting factors and the controlled output weighting factors are selected among them. In this study, the effect of output weighting factors is analyzed. According to the simulation results, it is recommended that the weighting factor of power be between 200 and 400 and that of ASI be between 200 and 600. In the near future, based on the study, optimization of power and ASI weighting factors will be performed at the same time.

  3. Monitoring Microbially Influenced Corrosion

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel

    and diffusional effects and unreliable corrosion rates, when biofilm and ferrous sulphide corrosion products cover the steel surface. Corrosion rates can be overestimated by a factor of 10 to 100 by electrochemical techniques. Weight loss coupons and ER are recommended as necessary basic monitoring techniques......Abstract Microbially influenced corrosion (MIC) of carbon steel may occur in media with microbiological activity of especially sulphate-reducing bacteria (SRB). The applicability and reliability of a number of corrosion monitoring techniques for monitoring MIC has been evaluated in experiments....... EIS might be used for detection of MIC as the appearance of very large capacitances can be attributed to the combined ferrous sulphide and biofilm formation. Capacitance correlates directly with sulphide concentration in sterile sulphide media. Keywords: Corrosion monitoring, carbon steel, MIC, SRB...

  4. Case-controlled Study on Risk Factors for the Development of Constipation in Hospitalized Patients

    OpenAIRE

    Ueki, Tetsuya; Nagai, Keiko; Ooe, Nobuharu; Nakashima, Mihoko N.; Nishida, Koyo; Nakamura, Junzo; Nakashima, Mikiro

    2011-01-01

    Constipation is a common problem in hospitalized patients; however, the relative risks of its development with various factors have not been clarified. To clarify the risk factors associated with constipation, we performed a case-controlled study of 165 hospitalized patients who were not laxative users on admission. They were divided into case (n=35) and control (n=130) groups according to laxative administration during hospitalization. Comparison of the patient backgrounds in the two groups ...

  5. Verification and validation of human factors issues in control room design and upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.; Collier, S. [Inst. for Energiteknikk, Halden (Norway). OECD Halden Reactor Project

    1999-12-01

    Systems, facilities and equipment are periodically updated during a power plant's lifetime. This has human factors implications, especially if the central control room is involved. Human factors work may therefore be required. There is an extensive literature on human factors itself, but not so much on how it is verified and validated. Therefore, HRP and the Swedish Nuclear Power Inspectorate commissioned a study. The objective was to review the literature and establish a knowledge base on verification and validation (V and V) of human factors issues. The report first discusses verification and validation as applied to human factors work. It describes a design process and the typical human factors topics involved. It then presents a generic method for V and V of human factors. This is built on a review of standards, guidelines and other references given in an annotated bibliography. The method is illustrated by application to some human factors topics.

  6. Verification and validation of human factors issues in control room design and upgrades

    International Nuclear Information System (INIS)

    Green, M.; Collier, S.

    1999-12-01

    Systems, facilities and equipment are periodically updated during a power plant's lifetime. This has human factors implications, especially if the central control room is involved. Human factors work may therefore be required. There is an extensive literature on human factors itself, but not so much on how it is verified and validated. Therefore, HRP and the Swedish Nuclear Power Inspectorate commissioned a study. The objective was to review the literature and establish a knowledge base on verification and validation (V and V) of human factors issues. The report first discusses verification and validation as applied to human factors work. It describes a design process and the typical human factors topics involved. It then presents a generic method for V and V of human factors. This is built on a review of standards, guidelines and other references given in an annotated bibliography. The method is illustrated by application to some human factors topics

  7. Controllability analysis of transcriptional regulatory networks reveals circular control patterns among transcription factors

    DEFF Research Database (Denmark)

    Österlund, Tobias; Bordel, Sergio; Nielsen, Jens

    2015-01-01

    % for the human network. The high controllability (low number of drivers needed to control the system) in yeast, mouse and human is due to the presence of internal loops in their regulatory networks where the TFs regulate each other in a circular fashion. We refer to these internal loops as circular control...... motifs (CCM). The E. coli transcriptional regulatory network, which does not have any CCMs, shows a hierarchical structure of the transcriptional regulatory network in contrast to the eukaryal networks. The presence of CCMs also has influence on the stability of these networks, as the presence of cycles...

  8. Novel barite chimneys at the Loki´s Castle Vent Field shed light on key factors shaping microbial communities and functions in hydrothermal systems

    Directory of Open Access Journals (Sweden)

    Ida Helene eSteen

    2016-01-01

    Full Text Available In order to fully understand the cycling of elements in hydrothermal systems it is critical to understand intra-field variations in geochemical and microbiological processes in both focused, high-temperature and diffuse, low-temperature areas. To reveal important causes and effects of this variation, we performed an extensive chemical and microbiological characterization of a low-temperature venting area in the Loki’s Castle Vent Field (LCVF. This area, located at the flank of the large sulfide mound, is characterized by numerous chimney-like barite (BaSO4 structures (≤ 1m high covered with white cotton-like microbial mats. Results from geochemical analyses, microscopy (FISH, SEM, 16S rRNA gene amplicon-sequencing and metatranscriptomics were compared to results from previous analyses of biofilms growing on black smoker chimneys at LCVF. Based on our results, we constructed a conceptual model involving the geochemistry and microbiology in the LCVF. The model suggests that CH4 and H2S are important electron donors for microorganisms in both high-temperature and low-temperature areas, whereas the utilization of H2 seems restricted to high-temperature areas. This further implies that sub-seafloor processes can affect energy-landscapes, elemental cycling, and the metabolic activity of primary producers on the seafloor. In the cotton-like microbial mats on top of the active barite chimneys, a unique network of single cells of Epsilonproteobacteria interconnected by threads of extracellular polymeric substances (EPS was seen, differing significantly from the long filamentous Sulfurovum filaments observed in biofilms on the black smokers. This network also induced nucleation of barite crystals and is suggested to play an essential role in the formation of the microbial mats and the chimneys. Furthermore, it illustrates variations in how different genera of Epsilonproteobacteria colonize and position cells in different vent fluid mixing zones within

  9. Microbial hydrocarbon degradation - bioremediation of oil spills

    Energy Technology Data Exchange (ETDEWEB)

    Atlas, R M [Louisville Univ., KY (United States). Dept. of Biology

    1991-01-01

    Bioremediation has become a major method employed in restoration of oil-polluted environments that makes use of natural microbial biodegradative activities. Bioremediation of petroleum pollutants overcomes the factors limiting rates of microbial hydrocarbon biodegradation. Often this involves using the enzymatic capabilities of the indigenous hydrocarbon-degrading microbial populations and modifying environmental factors, particularly concentrations of molecular oxygen, fixed forms of nitrogen and phosphate to achieve enhanced rates of hydrocarbon biodegradation. Biodegradation of oily sludges and bioremediation of oil-contaminated sites has been achieved by oxygen addition-e.g. by tilling soils in landfarming and by adding hydrogen peroxide or pumping oxygen into oiled aquifers along with addition of nitrogen- and phosphorous-containing fertilizers. The success of seeding oil spills with microbial preparations is ambiguous. Successful bioremediation of a major marine oil spill has been achieved based upon addition of nitrogen and phosphorus fertilizers. (author).

  10. The place of human-factors in the work of the Atomic Energy Control Board

    International Nuclear Information System (INIS)

    Barkow, B.

    1982-01-01

    The AECB do not effectively regulate human factors in nuclear power plants since they have no staff trained to do so. Two new positions are recommended and their activities are outlined. Special problems are identified in the certification of personnel, management information control, and in accommodating human factors to AECB style

  11. Dynamic increase and decrease of photonic crystal nanocavity Q factors for optical pulse control.

    Science.gov (United States)

    Upham, Jeremy; Tanaka, Yoshinori; Asano, Takashi; Noda, Susumu

    2008-12-22

    We introduce recent advances in dynamic control over the Q factor of a photonic crystal nanocavity system. By carefully timing a rapid increase of the Q factor from 3800 to 22,000, we succeed in capturing a 4ps signal pulse within the nanocavity with a photon lifetime of 18ps. By performing an additional transition of the Q factor within the photon lifetime, the held light is once again ejected from of the system on demand.

  12. Microbial activity at Yucca Mountain

    International Nuclear Information System (INIS)

    Horn, J.M.; Meike, A.

    1995-01-01

    The U.S. Department of Energy is engaged in a suitability study for a potential geological repository at Yucca Mountain, Nevada, for the containment and storage of commercially generated spent fuel and defense high-level nuclear waste. There is growing recognition of the role that biotic factors could play in this repository, either directly through microbially induced corrosion (MIC), or indirectly by altering the chemical environment or contributing to the transport of radionuclides. As a first step toward describing and predicting these processes, a workshop was held on April 10-12, 1995, in Lafayette, California. The immediate aims of the workshop were: (1) To identify microbially related processes relevant to the design of a radioactive waste repository under conditions similar to those at Yucca Mountain. (2) To determine parameters that are critical to the evaluation of a disturbed subterranean environment. (3) To define the most effective means of investigating the factors thus identified

  13. Microbial activity at Yucca Mountain

    Energy Technology Data Exchange (ETDEWEB)

    Horn, J.M.; Meike, A.

    1995-09-25

    The U.S. Department of Energy is engaged in a suitability study for a potential geological repository at Yucca Mountain, Nevada, for the containment and storage of commercially generated spent fuel and defense high-level nuclear waste. There is growing recognition of the role that biotic factors could play in this repository, either directly through microbially induced corrosion (MIC), or indirectly by altering the chemical environment or contributing to the transport of radionuclides. As a first step toward describing and predicting these processes, a workshop was held on April 10-12, 1995, in Lafayette, California. The immediate aims of the workshop were: (1) To identify microbially related processes relevant to the design of a radioactive waste repository under conditions similar to those at Yucca Mountain. (2) To determine parameters that are critical to the evaluation of a disturbed subterranean environment. (3) To define the most effective means of investigating the factors thus identified.

  14. Confirmatory factor analysis reveals a latent cognitive structure common to bipolar disorder, schizophrenia, and normal controls.

    Science.gov (United States)

    Schretlen, David J; Peña, Javier; Aretouli, Eleni; Orue, Izaskun; Cascella, Nicola G; Pearlson, Godfrey D; Ojeda, Natalia

    2013-06-01

    We sought to determine whether a single hypothesized latent factor structure would characterize cognitive functioning in three distinct groups. We assessed 576 adults (340 community controls, 126 adults with bipolar disorder, and 110 adults with schizophrenia) using 15 measures derived from nine cognitive tests. Confirmatory factor analysis (CFA) was conducted to examine the fit of a hypothesized six-factor model. The hypothesized factors included attention, psychomotor speed, verbal memory, visual memory, ideational fluency, and executive functioning. The six-factor model provided an excellent fit for all three groups [for community controls, root mean square error of approximation (RMSEA) schizophrenia, RMSEA = 0.06 and CFI = 0.98]. Alternate models that combined fluency with processing speed or verbal and visual memory reduced the goodness of fit. Multi-group CFA results supported factor invariance across the three groups. Confirmatory factor analysis supported a single six-factor structure of cognitive functioning among patients with schizophrenia or bipolar disorder and community controls. While the three groups clearly differ in level of performance, they share a common underlying architecture of information processing abilities. These cognitive factors could provide useful targets for clinical trials of treatments that aim to enhance information processing in persons with neurological and neuropsychiatric disorders. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. IMPROVING CONTROL ROOM DESIGN AND OPERATIONS BASED ON HUMAN FACTORS ANALYSES OR HOW MUCH HUMAN FACTORS UPGRADE IS ENOUGH ?

    Energy Technology Data Exchange (ETDEWEB)

    HIGGINS,J.C.; OHARA,J.M.; ALMEIDA,P.

    2002-09-19

    THE JOSE CABRERA NUCLEAR POWER PLANT IS A ONE LOOP WESTINGHOUSE PRESSURIZED WATER REACTOR. IN THE CONTROL ROOM, THE DISPLAYS AND CONTROLS USED BY OPERATORS FOR THE EMERGENCY OPERATING PROCEDURES ARE DISTRIBUTED ON FRONT AND BACK PANELS. THIS CONFIGURATION CONTRIBUTED TO RISK IN THE PROBABILISTIC SAFETY ASSESSMENT WHERE IMPORTANT OPERATOR ACTIONS ARE REQUIRED. THIS STUDY WAS UNDERTAKEN TO EVALUATE THE IMPACT OF THE DESIGN ON CREW PERFORMANCE AND PLANT SAFETY AND TO DEVELOP DESIGN IMPROVEMENTS.FIVE POTENTIAL EFFECTS WERE IDENTIFIED. THEN NUREG-0711 [1], PROGRAMMATIC, HUMAN FACTORS, ANALYSES WERE CONDUCTED TO SYSTEMATICALLY EVALUATE THE CR-LA YOUT TO DETERMINE IF THERE WAS EVIDENCE OF THE POTENTIAL EFFECTS. THESE ANALYSES INCLUDED OPERATING EXPERIENCE REVIEW, PSA REVIEW, TASK ANALYSES, AND WALKTHROUGH SIMULATIONS. BASED ON THE RESULTS OF THESE ANALYSES, A VARIETY OF CONTROL ROOM MODIFICATIONS WERE IDENTIFIED. FROM THE ALTERNATIVES, A SELECTION WAS MADE THAT PROVIDED A REASONABLEBALANCE BE TWEEN PERFORMANCE, RISK AND ECONOMICS, AND MODIFICATIONS WERE MADE TO THE PLANT.

  16. The design and operation of the THORP central control room: a human factors perspective

    International Nuclear Information System (INIS)

    Reed, Julie.

    1996-01-01

    The new Thermal Oxide Reprocessing Plant (THORP) at British Nuclear Fuels (BNFL) Sellafield Site is now operational. This paper describes the Central Control Room (CCR), focusing on the control system components. Throughout the design, commissioning and operation of THORP, human factors played an important part. (author)

  17. Risk factors for idiopathic orbital inflammation: a case-control study

    NARCIS (Netherlands)

    Bijlsma, Ward R.; van Gils, Carla H.; Paridaens, Dion; Mourits, Maarten P.; Kalmann, Rachel

    2011-01-01

    Objective To identify risk factors involved in the development of idiopathic orbital inflammation (IOI). Methods Case-control study of 69 adults who had had a first episode of IOI and 296 adult controls with rhegmatogenous retinal detachment (RD) selected from three orbital centres in The

  18. The role of nutrition as risk factor for polyneuropathy : a case-control study

    NARCIS (Netherlands)

    Visser, Nora A.; Notermans, Nicolette C.; de Vries, Jeanne H.M.; van den Berg, Leonard H.; Vrancken, Alexander F.J.E.

    2017-01-01

    The aim of this case–control study is to investigate the role of nutrition as risk factor for polyneuropathy. Three hundred eighteen patients with chronic idiopathic axonal polyneuropathy and 636 matched controls completed a validated food frequency questionnaire that covered nutrient intake and

  19. A case-control study of risk factors for male infertility in Southern ...

    African Journals Online (AJOL)

    Aim: The purpose of this study was to evaluate the association between selected potential socio-demographic and behavioural risk factors and infertility in Nigeria males. Methods: The study consisted of cases and controls. The cases were 150 males with proven male infertility, while the controls were 150 fertile males with ...

  20. Maternal sleep deprivation, sedentary lifestyle and cooking smoke: Risk factors for miscarriage: A case control study.

    Science.gov (United States)

    Samaraweera, Yasindu; Abeysena, Chrishantha

    2010-08-01

    To determine risk factors for miscarriage. A case control study was carried out at the gynaecological wards and antenatal clinics of the De Soysa Maternity Hospital in Sri Lanka. A case was defined as that of mothers with a confirmed diagnosis of partial or full expulsion of the fetus during the first 28 weeks of gestation. Controls comprised ante-natal clinic attendees whose period of gestation was sedentary lifestyle, exposure to cooking smoke and physical trauma during pregnancy were risk factors for miscarriage. Most of the risk factors are therefore modifiable.

  1. Factor structure, reliability, and validity of the Levenson's Locus of Control Scale in Iranian infertile people.

    Science.gov (United States)

    Maroufizadeh, Saman; Omani Samani, Reza; Amini, Payam; Navid, Behnaz

    2016-09-01

    This study examined psychometric properties of the Levenson's Locus of Control Scale among Iranian infertile patients. In all, 312 infertile patients completed the Levenson's Locus of Control Scale and Hospital Anxiety and Depression Scale. The confirmatory factor analysis indicated that the original three-factor model of Levenson's Locus of Control Scale was adequate ( χ 2 / df = 2.139; goodness-of-fit index = 0.88; root mean square error of approximation = 0.061; and standardized root mean square residual = 0.076). The Cronbach's alpha of the subscales ranged from 0.56 to 0.67. The Levenson's Locus of Control Scale subscales significantly correlated with anxiety and depression, showing an acceptable convergent validity. In conclusion, the Levenson's Locus of Control Scale has adequate reliability and validity and can be used to measure locus of control orientation in Iranian infertile patients.

  2. Factors associated with glycemic control in people with diabetes at the Family Health Strategy in Pernambuco

    Directory of Open Access Journals (Sweden)

    Rodrigo Fonseca Lima

    Full Text Available Abstract OBJECTIVE Identifying factors associated with glycemic control in people with type 2 Diabetes Mellitus (DM registered in the Family Health Strategy (FHS in Pernambuco, Brazil. METHOD Associations between glycemic control (glycosylated hemoglobin A lower or equal to 7% presented by people with DM and variables related to sociodemographic conditions, lifestyle, characteristics of diabetes, treatment and follow-up of patients by health services were investigated by multiple regression. RESULTS More than 65% of the participants presented inadequate glycemic control, especially those with lower age, longer illness duration, more annual contacts with FHS and complex therapeutic regimen. People with DM without referrals to specialists presented greater glycemic control. Associations with education level and obesity did not remain significant in the multivariate model. CONCLUSION The evolution of diabetes hinders adequate control, however, attention to younger people with DM and referrals to specialists are factors that can improve glycemic control.

  3. Microbial analysis of in situ biofilm formation in drinking water distribution systems: implications for monitoring and control of drinking water quality.

    Science.gov (United States)

    Douterelo, Isabel; Jackson, M; Solomon, C; Boxall, J

    2016-04-01

    Biofilm formation in drinking water distribution systems (DWDS) is influenced by the source water, the supply infrastructure and the operation of the system. A holistic approach was used to advance knowledge on the development of mixed species biofilms in situ, by using biofilm sampling devices installed in chlorinated networks. Key physico-chemical parameters and conventional microbial indicators for drinking water quality were analysed. Biofilm coverage on pipes was evaluated by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The microbial community structure, bacteria and fungi, of water and biofilms was assessed using pyrosequencing. Conventional wisdom leads to an expectation for less microbial diversity in groundwater supplied systems. However, the analysis of bulk water showed higher microbial diversity in groundwater site samples compared with the surface water site. Conversely, higher diversity and richness were detected in biofilms from the surface water site. The average biofilm coverage was similar among sites. Disinfection residual and other key variables were similar between the two sites, other than nitrates, alkalinity and the hydraulic conditions which were extremely low at the groundwater site. Thus, the unexpected result of an exceptionally low diversity with few dominant genera (Pseudomonas and Basidiobolus) in groundwater biofilm samples, despite the more diverse community in the bulk water, is attributed to the low-flow hydraulic conditions. This finding evidences that the local environmental conditions are shaping biofilm formation, composition and amount, and hence managing these is critical for the best operation of DWDS to safeguard water quality.

  4. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport

    Science.gov (United States)

    The objective of this study was to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs following deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to one...

  5. Human factors design review guidelines for advanced nuclear control room technologies

    International Nuclear Information System (INIS)

    O'Hara, J.; Brown, W.; Granda, T.; Baker, C.

    1991-01-01

    Advanced control rooms (ACRs) for future nuclear power plants are being designed utilizing computer-based technologies. The US Nuclear Regulatory Commission reviews the human engineering aspects of such control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported in order to protect public health and safety. This paper describes the rationale, general approach, and initial development of an NRC Advanced Control Room Design Review Guideline. 20 refs., 1 fig

  6. Survey of control-room design practices with respect to human factors engineering

    International Nuclear Information System (INIS)

    Seminara, J.L.; Parsons, S.O.

    1980-01-01

    Human factors engineering is an interdisciplinary speciality concerned with influencing the design of equipment systems, facilities, and operational environments to promote safe, efficient, and reliable operator performance. This emphasis has been applied to most military and space systems in the past 30 y. A review of five nuclear power-plant control rooms, reported in the November-December 1977 issue of Nuclear Safety, revealed that human factors principles of design have generally not been incorporated in present-generation control rooms. This article summarizes the findings of a survey of 20 control-board designers from a mix of nuclear steam-supply system and architect-engineering firms. The interviews with these designers probed design methods currently used in developing control rooms. From these data it was concluded that there is currently no consistent, formal, uniform concern for the human factors aspects of control-room design on the part of the design organizations, the utilities, or the Nuclear Regulatory Commission. Although all the parties involved are concerned with human factors issues, this responsibility is not focused, and human factors yardsticks, or design standards, specific to power plants have not been evolved and applied in the development and verification of control-room designs from the standpoint of the man-machine interface

  7. Microfluidics expanding the frontiers of microbial ecology.

    Science.gov (United States)

    Rusconi, Roberto; Garren, Melissa; Stocker, Roman

    2014-01-01

    Microfluidics has significantly contributed to the expansion of the frontiers of microbial ecology over the past decade by allowing researchers to observe the behaviors of microbes in highly controlled microenvironments, across scales from a single cell to mixed communities. Spatially and temporally varying distributions of organisms and chemical cues that mimic natural microbial habitats can now be established by exploiting physics at the micrometer scale and by incorporating structures with specific geometries and materials. In this article, we review applications of microfluidics that have resulted in insightful discoveries on fundamental aspects of microbial life, ranging from growth and sensing to cell-cell interactions and population dynamics. We anticipate that this flexible multidisciplinary technology will continue to facilitate discoveries regarding the ecology of microorganisms and help uncover strategies to control microbial processes such as biofilm formation and antibiotic resistance.

  8. Applying human factors to the design of control centre and workstation of a nuclear reactor

    International Nuclear Information System (INIS)

    Santos, Isaac J.A. Luquetti dos; Carvalho, Paulo V.R.; Goncalves, Gabriel de L.; Souza, Tamara D.M.F.; Falcao, Mariana A.

    2013-01-01

    Human factors is a body of scientific factors about human characteristics, covering biomedical, psychological and psychosocial considerations, including principles and applications in the personnel selection areas, training, job performance aid tools and human performance evaluation. Control Centre is a combination of control rooms, control suites and local control stations which are functionally related and all on the same site. Digital control room includes an arrangement of systems, equipment such as computers and communication terminals and workstations at which control and monitoring functions are conducted by operators. Inadequate integration between control room and operators reduces safety, increases the operation complexity, complicates operator training and increases the likelihood of human errors occurrence. The objective of this paper is to present a specific approach for the conceptual and basic design of the control centre and workstation of a nuclear reactor used to produce radioisotope. The approach is based on human factors standards, guidelines and the participation of a multidisciplinary team in the conceptual and basic phases of the design. Using the information gathered from standards and from the multidisciplinary team, an initial sketch 3D of the control centre and workstation are being developed. (author)

  9. Applying human factors to the design of control centre and workstation of a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Isaac J.A. Luquetti dos; Carvalho, Paulo V.R.; Goncalves, Gabriel de L., E-mail: luquetti@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Souza, Tamara D.M.F.; Falcao, Mariana A. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Dept. de Desenho Industrial

    2013-07-01

    Human factors is a body of scientific factors about human characteristics, covering biomedical, psychological and psychosocial considerations, including principles and applications in the personnel selection areas, training, job performance aid tools and human performance evaluation. Control Centre is a combination of control rooms, control suites and local control stations which are functionally related and all on the same site. Digital control room includes an arrangement of systems, equipment such as computers and communication terminals and workstations at which control and monitoring functions are conducted by operators. Inadequate integration between control room and operators reduces safety, increases the operation complexity, complicates operator training and increases the likelihood of human errors occurrence. The objective of this paper is to present a specific approach for the conceptual and basic design of the control centre and workstation of a nuclear reactor used to produce radioisotope. The approach is based on human factors standards, guidelines and the participation of a multidisciplinary team in the conceptual and basic phases of the design. Using the information gathered from standards and from the multidisciplinary team, an initial sketch 3D of the control centre and workstation are being developed. (author)

  10. The significance of microsatellite instability in colorectal cancer after controlling for clinicopathological factors.

    Science.gov (United States)

    Kang, Sanghee; Na, Younghyun; Joung, Sung Yup; Lee, Sun Il; Oh, Sang Cheul; Min, Byung Wook

    2018-03-01

    The colorectal cancer (CRC) patients with microsatellite instability (MSI) have distinct clinicopathological characteristics consisting of factors predicting positive and negative outcomes, such as a high lymph node harvest and poor differentiation. In this study, we measured the value of MSI as a prognostic factor after controlling for these discrepant factors. A total of 603 patients who underwent curative surgery for stages I to III colorectal cancer were enrolled. The patients were divided into microsatellite instability high (MSI-H) and microsatellite stable/microsatellite instability low (MSS/MSI-L) groups. Propensity score matching was used to match clinicopathological factors between the 2 groups. MSI-H patients had a high lymph node harvest (median: 31.0 vs 23.0, P controlling for pathological characteristics, MSI-H could be a potent prognostic factor regarding patient survival.

  11. Human factors review of nuclear power plant control room design. Final report

    International Nuclear Information System (INIS)

    Seminara, J.L.; Gonzalez, W.R.; Parsons, S.O.

    1976-11-01

    The human factors aspects of five representative nuclear power plant control rooms were evaluated using such methods as a checklist guided observation system, structured interviews with operators and trainers, direct observations of operator behavior, task analyses and procedure evaluation, and historical error analyses. The human factors aspects of design practices are illustrated, and many improvements in current practices are suggested. The study recommends that a detailed set of applicable human factors standards be developed to stimulate a uniform and systematic concern for human factors in design considerations

  12. Sociocultural Factors Affecting Unplanned Deliveries at Home: A Community-Based Case Control Study.

    Science.gov (United States)

    Catak, Binali; Oner, Can

    2015-01-01

    Unplanned home deliveries can vary with social and cultural factors. The aim of this study was to define the risk factors of unplanned home births. This case control study was conducted in Istanbul, Turkey. The study group was composed of 229 women who had unplanned home delivery. Six factors (presence of health insurance, duration of living in Istanbul, educational status of the woman, the number of individuals living in the household, the age of the woman at the time of current delivery, and the status of having received care prior to delivery) were determined as independent risk factors for unplanned deliveries at home.

  13. Research on cognitive reliability model for main control room considering human factors in nuclear power plants

    International Nuclear Information System (INIS)

    Jiang Jianjun; Zhang Li; Wang Yiqun; Zhang Kun; Peng Yuyuan; Zhou Cheng

    2012-01-01

    Facing the shortcomings of the traditional cognitive factors and cognitive model, this paper presents a Bayesian networks cognitive reliability model by taking the main control room as a reference background and human factors as the key points. The model mainly analyzes the cognitive reliability affected by the human factors, and for the cognitive node and influence factors corresponding to cognitive node, a series of methods and function formulas to compute the node cognitive reliability is proposed. The model and corresponding methods can be applied to the evaluation of cognitive process for the nuclear power plant operators and have a certain significance for the prevention of safety accidents in nuclear power plants. (authors)

  14. Factors Associated with Long-Term Control of Type 2 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Mohammed Badedi

    2016-01-01

    Full Text Available Aims. This study assessed factors associated with glycemic control among Saudi patients with Type 2 diabetes mellitus (T2DM. Methods. We conducted an analytical cross-sectional study, which included a random sample of 288 patients with T2DM proportional to the diabetes population of each primary health care center in Jazan city, Kingdom of Saudi Arabia. Results. More than two-thirds (74% of patients had poor glycemic control. Lack of education, polypharmacy, and duration of diabetes ≥ 7 years were significantly associated with higher glycated hemoglobin (HbA1c. Moreover, patients who were smoker or divorced were significantly more likely to have higher HbA1c. The patients who did not comply with diet or take their medications as prescribed had poor glycemic control. The study found lower HbA1c levels among patients who received family support or had close relationship with their physicians. Similarly, knowledgeable patients towards diabetes or those with greater confidence in ability to manage self-care behaviors had a lower HbA1c. In contrast, risk factors such as depression or stress were significantly correlated with poorer glycemic control. Conclusion. The majority of T2DM patients had poor glycemic control. The study identified several factors associated with glycemic control. Effective and tailored interventions are needed to mitigate exposure to these risk factors. This would improve glycemic control and reduce the risks inherent to diabetes complications.

  15. Factors Associated with Long-Term Control of Type 2 Diabetes Mellitus.

    Science.gov (United States)

    Badedi, Mohammed; Solan, Yahiya; Darraj, Hussain; Sabai, Abdullah; Mahfouz, Mohamed; Alamodi, Saleh; Alsabaani, Abdullah

    2016-01-01

    Aims. This study assessed factors associated with glycemic control among Saudi patients with Type 2 diabetes mellitus (T2DM). Methods. We conducted an analytical cross-sectional study, which included a random sample of 288 patients with T2DM proportional to the diabetes population of each primary health care center in Jazan city, Kingdom of Saudi Arabia. Results. More than two-thirds (74%) of patients had poor glycemic control. Lack of education, polypharmacy, and duration of diabetes ≥ 7 years were significantly associated with higher glycated hemoglobin (HbA1c). Moreover, patients who were smoker or divorced were significantly more likely to have higher HbA1c. The patients who did not comply with diet or take their medications as prescribed had poor glycemic control. The study found lower HbA1c levels among patients who received family support or had close relationship with their physicians. Similarly, knowledgeable patients towards diabetes or those with greater confidence in ability to manage self-care behaviors had a lower HbA1c. In contrast, risk factors such as depression or stress were significantly correlated with poorer glycemic control. Conclusion. The majority of T2DM patients had poor glycemic control. The study identified several factors associated with glycemic control. Effective and tailored interventions are needed to mitigate exposure to these risk factors. This would improve glycemic control and reduce the risks inherent to diabetes complications.

  16. Human factors engineering applied to Control Centre Design of a research nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Farias, Larissa P. de; Santos, Isaac J.A. Luquetti dos; Carvalho, Paulo V.R., E-mail: larissapfarias@ymail.com [Instituto de Engenharia Nuclear (DENN/SEESC/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab, de Usabilidade e Confiabilidade Humana; Monteiro, Beany G. [Universidade Federal do Rio Janeiro (UFRJ), Rio Janeiro, RJ (Brazil). Departamento de Desenho Industrial

    2017-07-01

    The Human Factors Engineering (HFE) program is an essential aspect for the design of nuclear installations. The overall aim of the HFE program is the improvement of the operational reliability and safety of plant operation. The HFE program main purpose is to ensure that human factor practices are incorporated into the plant design, emphasizing man-machine interface issues and design improvement of the nuclear reactor Control Centre. The Control Centre of nuclear reactor is a combination of control rooms, control suites and local control stations, which are functionally connected and located on the reactor site. The objective of this paper is to present a design approach for the Control Centre of a nuclear reactor used to produce radioisotopes and for nuclear research, including human factor issues. The design approach is based on participatory design principles, using human factor standards, ergonomic guidelines, and the participation of a multidisciplinary team during all design phases. Using the information gathered, an initial sketch 3D of the Control Centre was developed. (author)

  17. Human factors engineering applied to Control Centre Design of a research nuclear reactor

    International Nuclear Information System (INIS)

    Farias, Larissa P. de; Santos, Isaac J.A. Luquetti dos; Carvalho, Paulo V.R.; Monteiro, Beany G.

    2017-01-01

    The Human Factors Engineering (HFE) program is an essential aspect for the design of nuclear installations. The overall aim of the HFE program is the improvement of the operational reliability and safety of plant operation. The HFE program main purpose is to ensure that human factor practices are incorporated into the plant design, emphasizing man-machine interface issues and design improvement of the nuclear reactor Control Centre. The Control Centre of nuclear reactor is a combination of control rooms, control suites and local control stations, which are functionally connected and located on the reactor site. The objective of this paper is to present a design approach for the Control Centre of a nuclear reactor used to produce radioisotopes and for nuclear research, including human factor issues. The design approach is based on participatory design principles, using human factor standards, ergonomic guidelines, and the participation of a multidisciplinary team during all design phases. Using the information gathered, an initial sketch 3D of the Control Centre was developed. (author)

  18. A unique model system of microbial carbonate precipitation: Stromatolites of Lagoa Vermelha, Brazil

    Science.gov (United States)

    Warthmann, R. J.; Vasoncelos, C.; van Lith, Y.; Visscher, P. T.; McKenzie, J. A.

    2003-04-01

    Modern stromatolites are recognized as analogues to fossil laminated structures, which are remains of microbial activity that are widely found in sedimentary rocks beginning in the Neo-Archean, but are quite rare today. The key difference of modern microbial mats and stromatolites compared to ancient examples is the type of lithification. A few marine and hypersaline microbial mats have been observed to precipitate carbonates, and only in Shark Bay (Western, Australia) and Highborne Cay (Bahamas) has the formation of continuous laminae of carbonates been observed. Lagoa Vermelha, a moderate hypersaline lagoon in Rio de Janeiro, Brazil, offers the ideal conditions to promote lithification. Calcified, sometimes dolomitic stromatolites grow on the sediment surface, whereas within the sediments dolomite precipitates. The factors controlling carbonate precipitation in Lagoa Vermelha are the changing water chemistry and the special hydrology, combined with a high primary production by cyanobacteria, a high rate of respiration and the absence of higher organisms. Here, we present a study of the physico-chemical parameters, microbial processes and bio-minerals associated with these stromatolites and microbial mats. This approach provides boundary conditions to better understand dolomite formation. Several discrete lithified calcium carbonate layers are present. The first lithified layer is found beneath a 2-mm-thick biofilm, which contains Gloeocapsa. Below the underlying dense Microcoleus layer, the second micrite deposit is observed at 4-5 mm depth. Successive micritic laminae are preserved in the layer of decaying cyanobacteria that harbors large numbers of purple sulfur bacteria, heterotrophic microbes and sulfate-reducing bacteria. C-isotope studies of the carbonate layers indicate a contribution of organic derived carbon associated with microbial processes, such as sulfate reduction. The O-isotopic values indicate an evaporitic enrichment of the water. Understanding

  19. Interleukin-19: a constituent of the regulome that controls antigen presenting cells in the lungs and airway responses to microbial products.

    Directory of Open Access Journals (Sweden)

    Carol Hoffman

    Full Text Available Interleukin (IL-19 has been reported to enhance chronic inflammatory diseases such as asthma but the in vivo mechanism is incompletely understood. Because IL-19 is produced by and regulates cells of the monocyte lineage, our studies focused on in vivo responses of CD11c positive (CD11c+ alveolar macrophages and lung dendritic cells.IL-19-deficient (IL-19-/- mice were studied at baseline (naïve and following intranasal challenge with microbial products, or recombinant cytokines. Naïve IL-19-/- mixed background mice had a decreased percentage of CD11c+ cells in the bronchoalveolar-lavage (BAL due to the deficiency in IL-19 and a trait inherited from the 129-mouse strain. BAL CD11c+ cells from fully backcrossed IL-19-/- BALB/c or C57BL/6 mice expressed significantly less Major Histocompatibility Complex class II (MHCII in response to intranasal administration of lipopolysaccharide, Aspergillus antigen, or IL-13, a pro-allergic cytokine. Neurogenic-locus-notch-homolog-protein-2 (Notch2 expression by lung monocytes, the precursors of BAL CD11c+ cells, was dysregulated: extracellular Notch2 was significantly decreased, transmembrane/intracellular Notch2 was significantly increased in IL-19-/- mice relative to wild type. Instillation of recombinant IL-19 increased extracellular Notch2 expression and dendritic cells cultured from bone marrow cells in the presence of IL-19 showed upregulated extracellular Notch2. The CD205 positive subset among the CD11c+ cells was 3-5-fold decreased in the airways and lungs of naïve IL-19-/- mice relative to wild type. Airway inflammation and histological changes in the lungs were ameliorated in IL-19-/- mice challenged with Aspergillus antigen that induces T lymphocyte-dependent allergic inflammation but not in IL-19-/- mice challenged with lipopolysaccharide or IL-13.Because MHCII is the molecular platform that displays peptides to T lymphocytes and Notch2 determines cell fate decisions, our studies suggest that

  20. Microbial interactions in drinking water biofilms

    OpenAIRE

    Simões, Lúcia C.; Simões, M.; Vieira, M. J.

    2007-01-01

    Drinking water distribution networks may be viewed as a large reactor where a number of chemical and microbiological processes are taking place. Control of microbial growth in drinking water distribution systems (DWDS) often achieved through the addition of disinfectants, is essential to limit the spread of waterborne pathogens. However, microorganisms can resist disinfection through protection within biofilms and resistant host cells. Recent studies into the microbial ecology ...

  1. Bar-coded pyrosequencing reveals the responses of PBDE-degrading microbial communities to electron donor amendments.

    Directory of Open Access Journals (Sweden)

    Meiying Xu

    Full Text Available Polybrominated diphenyl ethers (PBDEs can be reductively degraded by microorganisms under anaerobic conditions. However, little is known about the effect of electron donors on microbial communities involved in PBDEs degradation. Here we employed 454 Titanium pyrosequencing to examine the phylogenetic diversity, composition, structure and dynamics of microbial communities from microcosms under the conditions of different electron donor amendments. The community structures in each of the five alternate electron donor enrichments were significantly shifted in comparison with those of the control microcosm. Commonly existing OTUs between the treatment and control consortia increased from 5 to 17 and more than 50% of OTUs increased around 13.7 to 186 times at least in one of the microcosms after 90-days enrichment. Although the microbial communities at different taxonomic levels were significantly changed by different environmental variable groups in redundancy analysis, significant correlations were observed between the microbial communities and PBDE congener profiles. The lesser-brominated PBDE congeners, tri-BDE congener (BDE-32 and hexa-BDE, were identified as the key factors shaping the microbial community structures at OTU level. Some rare populations, including the known dechlorinating bacterium, Dehalobacter, showed significant positive-correlation with the amounts of PBDE congeners in the consortia. The same results were also observed on some unclassified bacteria. These results suggest that PBDEs-degrading microbial communities can be successfully enriched, and their structures and compositions can be manipulated through adjusting the environmental parameters.

  2. Microbial electrosynthetic cells

    Energy Technology Data Exchange (ETDEWEB)

    May, Harold D.; Marshall, Christopher W.; Labelle, Edward V.

    2018-01-30

    Methods are provided for microbial electrosynthesis of H.sub.2 and organic compounds such as methane and acetate. Method of producing mature electrosynthetic microbial populations by continuous culture is also provided. Microbial populations produced in accordance with the embodiments as shown to efficiently synthesize H.sub.2, methane and acetate in the presence of CO.sub.2 and a voltage potential. The production of biodegradable and renewable plastics from electricity and carbon dioxide is also disclosed.

  3. Human factors inspection of current control room panel in Jose Cabrera NPP

    International Nuclear Information System (INIS)

    Almeida, P.; O'Hara, J.; Higgins, J.

    2002-01-01

    Within the process of renewal of Exploitation Permit of Jose Cabrera Nuclear Power Plant, UNION FENOSA GENERACIO, S. A. (UFG) has carried out an analysis and evaluation project regarding human factors implications of current control room panel arrangement. The project has been developed in two phases. In the first phase, leaded by EPRI and carried out by experts from SAIC, an independent review from a double viewpoint of human reliability and human factors was developed. In the second phase, a multidisciplinary team (composed by human factors, risk analysis, operation, engineering, training and instrumentation and controls experts) has developed a study on human factors implications of current panel arrangement, following the methodology pointed out in NUREG-0711. The project has been developed under the direction of Brookhaven National Laboratory (BNL), organisation that has authored the aforementioned methodology, with the participation of UFG and SOLUZIONA Ingenieria. For the development of the second study the following steps were taken: Firstly, the potential effects of panel arrangement on crew performance were identified its real evidence was analysed and the goals for the improvement of control room operation were established; following NUREG-0711. After this, several design alternatives that addressed these goals were identified and were analysed along three dimensions: human factors, risk analysis and economic costs. Finally the results of these evaluations were combined using a multi-attribute decision method to arrive at a recommended alternative as he best proposal to incorporate human factors criteria and good practices in the design of control room panels. (Author)

  4. Estratificación epidemiológica en el control de los factores de riesgo de la tuberculosis Epidemiological stratification to control the risk factors of tuberculosis

    Directory of Open Access Journals (Sweden)

    Elba Nieves Moreno Díaz

    2011-12-01

    Full Text Available Se realizó un estudio descriptivo longitudinal, con el objetivo de implementar la estratificación epidemiológica en el control de los factores de riesgo de la tuberculosis, provincia Pinar del Río, 2008-2010. El universo de estudio lo constituyó, los habitantes de la provincia en cada uno de los años estudiados. Se revisó el registro de dispensarización y las encuestas epidemiológicas; de ellos se obtuvieron los factores de riesgo: alcoholismo, hábito de fumar, diabetes mellitus, ancianos solos, desnutrición, inmunodeprimidos y casos viviendo con VIH/Sida. Para el procesamiento de la información se trabajó con Microsoft Excel y MapInfo Professional. Se utilizó la metodología estratificación epidemiológica de riesgo hasta nivel municipal; los estratos para los factores de riesgo como para la enfermedad, se clasificaron en: muy alto, alto, mediano y bajo riesgo. Para determinar la significación de cambios se utilizó la prueba Mc Nemar. Los resultados mostraron que en el 2009, el 50% de los municipios que en la estratificación del 2008 estaban en el estrato de muy alto y alto riesgo, el 85,7% cambiaran de estratos, lo que indica un mejor control de los factores de riesgo. El proceso de estratificación en el 2010, no logró cambios favorables en los municipios con mayor riesgo en el 2008, estando el 65% clasificado en estratos de muy alto y alto riesgo, pues el plan de acción previsto, no fue ejecutado con efectividad y seriedad por los jefes de programa, debido a inestabilidad y ausencia de los mismos en los municipios de mayor riesgo.A descriptive, longitudinal study aimed at implementing epidemiological stratification to control the risk factors of tuberculosis in Pinar del Rio province was carried out form 2008 to 2010. The target group was comprised of the inhabitants of the province for each of the years under study. Records and epidemiological survey were revised; taking into account the risk factors of alcoholism

  5. Continuous infusion of recombinant activated factor VII for bleeding control after lobectomy in a patient with inherited factor VII deficiency.

    Science.gov (United States)

    Miyata, Naoko; Isaka, Mitsuhiro; Kojima, Hideaki; Maniwa, Tomohiro; Takahashi, Shoji; Takamiya, Osamu; Ohde, Yasuhisa

    2016-03-01

    Inherited factor VII (FVII) deficiency is a rare recessive inherited coagulation disorder with limited available information, especially in patients undergoing major thoracic surgery. In addition, an optimal management strategy for the disease has not been defined. We herein report a case involving a 61-year-old man with asymptomatic FVII deficiency who underwent a right middle and lower lobectomy to treat lung cancer. To the best of our knowledge, the present report is the first to describe the use of recombinant activated FVII continuous infusion for bleeding control after a major thoracic surgery in a patient with inherited FVII deficiency.

  6. A possible methodological approach to setting up control level of radiation factors

    International Nuclear Information System (INIS)

    Devyatajkin, E.V.; Abramov, Yu.V.

    1986-01-01

    The mathematical formalization of the concept of control levels (CL) which enables one to obtain CL numerical values of controllable parameters required for rapid control purposes is described. The initial data for the assessment of environmental radioactivity are the controllable parameter values that is practical characteristic of controllable radiation factor showing technically measurable or calculation value. The controllable parameters can be divided into two classes depending on the degree of radiation effect on a man: possessing additivity properties (dosimetric class) and non-possessing (radiation class, which comprises the results of control of medium alteration dynamics, equipment operation safety, completeness of protection measures performance). The CL calculation formulas with account for requirements of radiation safety standards (RSS-76) are presented

  7. Human factors engineering control-room-design review/audit report: Palo Verde Nuclear Generating Station, Arizona Public Service Company

    International Nuclear Information System (INIS)

    Savage, J.W.; Lappa, D.A.

    1981-01-01

    A human factors engineering design review of the Palo Verde control room simulator was performed at the site on September 15 through September 17, 1981. Observed human factors design discrepancies were given priority ratings. This report summarizes the team's observations of the control room design and layout and of the control room operators' interface with the control room environment. A list of the human factors strengths observed in the Palo Verde control room simulator is given

  8. Operation optimization of a photo-sequencing batch reactor for wastewater treatment: Study on influencing factors and impact on symbiotic microbial ecology.

    Science.gov (United States)

    Ye, Jianfeng; Liang, Junyu; Wang, Liang; Markou, Giorgos; Jia, Qilong

    2018-03-01

    Wastewater treatment technology with better energy efficiency and recyclability is in urgent demand. Photo-Sequencing batch reactor (SBR), which introduces microalgae into conventional SBR, is considered to have more potential for resource recycling. In this study, a photo-SBR was evaluated through the manipulation of several key operational parameters, i.e., aeration strength, light supply intensity and time per cycle, and solid retention time (SRT). The algal-bacterial symbiotic system had the potential of removing COD, NH 4 + -N and TN with limited aeration, representing the advantage of energy-saving by low aeration requirement. Maintaining appropriate proportion of microalgae in the symbiotic system is critical for good system performance. Introducing microalgae into conventional SBR has obvious impact on the original microbial ecology. When the concentration of microalgae is too high (>4.60 mg Chl/L), the inhibition on certain phyla of bacteria, e.g., Bacteroidetes and Actinobacteria, would become prominent and not conducive to the stable operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. RF control at transient beamloading for high-duty-factor linacs

    Energy Technology Data Exchange (ETDEWEB)

    Chernogubovsky, M.A.; Sugimoto, Masayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1998-08-01

    An effective RF control with the transient beamloading is the major issue in the operation of the high-duty-factor linacs to suppress the undesirable beam loss. The RF control method is considered to obtain the control principle and the state equation, under the analysis of electrodynamical properties of the excitation in the resonator of the linac due to the transient beamloading. The concept of the directional selective coupling is applied for the RF system to define the main characteristics and to optimize the RF control parameters. (author)

  10. Microbial changes during pregnancy, birth and infancy

    Directory of Open Access Journals (Sweden)

    Meital Nuriel-Ohayon

    2016-07-01

    Full Text Available Several healthy developmental processes such as pregnancy, fetal development and infant development include a multitude of physiological changes: weight gain, hormonal and metabolic changes, as well as immune changes. In this review we present an additional important factor which both influences and is affected by these physiological processes- the microbiome. We summarize the known changes in microbiota composition at a variety of body sites including gut, vagina, oral cavity and placenta, throughout pregnancy, fetal development and early childhood. There is still a lot to be discovered; yet several pieces of research point to the healthy desired microbial changes. Future research is likely to unravel precise roles and mechanisms of the microbiota in gestation; perhaps linking the metabolic, hormonal and immune changes together. Although some research has started to link microbial dysbiosis and specific microbial populations with unhealthy pregnancy complications, it is important to first understand the context of the natural healthy microbial changes occurring. Until recently the placenta and developing fetus were considered to be germ free, containing no apparent microbiome. We present multiple study results showing distinct microbiota compositions in the placenta and meconium, alluding to early microbial colonization. These results may change dogmas and our overall understanding of the importance and roles of microbiota from the beginning of life. We further review the main factors shaping the infant microbiome- modes of delivery, feeding, weaning, and exposure to antibiotics. Taken together, we are starting to build a broader understanding of healthy vs. abnormal microbial alterations throughout major developmental time-points.

  11. Microbial diversity arising from thermodynamic constraints

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-01-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments. PMID:27035705

  12. Microbial diversity arising from thermodynamic constraints.

    Science.gov (United States)

    Großkopf, Tobias; Soyer, Orkun S

    2016-11-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments.

  13. Crystal structure of the tyrosine kinase domain of the hepatocyte growth factor receptor c-Met and its complex with the microbial alkaloid K-252a

    OpenAIRE

    Schiering, Nikolaus; Knapp, Stefan; Marconi, Marina; Flocco, Maria M.; Cui, Jean; Perego, Rita; Rusconi, Luisa; Cristiani, Cinzia

    2003-01-01

    The protooncogene c-met codes for the hepatocyte growth factor receptor tyrosine kinase. Binding of its ligand, hepatocyte growth factor/scatter factor, stimulates receptor autophosphorylation, which leads to pleiotropic downstream signaling events in epithelial cells, including cell growth, motility, and invasion. These events are mediated by interaction of cytoplasmic effectors, generally through Src homology 2 (SH2) domains, with two phosphotyrosine-containing sequence motifs in the unique...

  14. A case-control study of risk factors for bovine cysticercosis in Danish cattle herds

    DEFF Research Database (Denmark)

    Calvo Artavia, Francisco Fernando; Nielsen, Liza Rosenbaum; Dahl, J.

    2013-01-01

    than in countries with few lightly infected cases per year. The aim of the present case-control study was to quantify associations between potential herd-level risk factors and BC in Danish cattle herds. Risk factors can be used in the design of a risk-based meat inspection system targeted towards...... a questionnaire and register data from the Danish Cattle Database were grouped into meaningful variables and used to investigate the risk factors for BC using a multivariable logistic regression model. Case herds were almost three times more likely than control herds to let all or most animals out grazing. Case...... the animals with the highest risk of BC. Cases (n = 77) included herds that hosted at least one animal diagnosed with BC at meat inspection, from 2006 to 2010. Control herds (n = 231) consisted of randomly selected herds that had not hosted any animals diagnosed with BC between 2004 and 2010. The answers from...

  15. Effects of Biofertilizer Containing Microbial of N-fixer, P Solubilizer and Plant Growth Factor Producer on Cabbage (Brassica oleraceae var. Capitata Growth And Soil Enzymatic Activities: A Greenhouse Trial