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Sample records for magnetic biocidal screening

  1. Biocidal and inhibitory activity screening of de novo synthesized surfactants against two eukaryotic and two prokaryotic microbial species.

    PubMed

    Tiecco, Matteo; Cardinali, Gianluigi; Roscini, Luca; Germani, Raimondo; Corte, Laura

    2013-11-01

    Thirty-six quaternary ammonium salts, of which 28 structurally different non-commercially available surfactants, were tested to screen their biocidal and inhibitory antimicrobial activity. Their activity was compared to commercially available amphiphiles as well as to non-amphiphilic quaternary ammonium salts. As target of these compounds four microbial species were employed of which two (Saccharomyces cerevisiae and Candida albicans) were important yeast in the food and clinical environment and the other two (Escherichia coli and Listeria innocua) represented the Gram negative and positive bacteria, respectively. The surfactants showed the ability to kill the microbial cells in water solution and to variably hamper their growth onto agar medium. The non-amphiphilic compounds (which represent analogues of some surfactants used in this study, since they have the same head group but no hydrophobic portion) had little effect in solution and no effect against the microbial growth on plate. Amphoteric and non-amphoteric zwitterionic surfactants showed reduced biocidal activity. The most active antimicrobial agent was N-tetradecyltropinium bromide (23S) surfactant. The presence of cells did not significantly affect the ability to form micelles, as demonstrated by comparative conductometric measurements.

  2. DNA incision evaluation, binding investigation and biocidal screening of novel metallonucleases of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione based Knoevenagel condensate having methionine: Synthesis and structural validation

    NASA Astrophysics Data System (ADS)

    Chandrasekar, Thiravidamani; Pravin, Narayanaperumal; Raman, Natarajan

    2015-02-01

    Four new metallonucleases of the composition [MLCl] (where M = Cu(II), Ni(II), Zn(II) and Co(II); L = Knoevenagel condensate Schiff base, obtained by the condensation reaction of 1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,6-diene-3,5-dione with p-nitrobenzaldehyde and methionine amino acid) have been synthesised and characterized thoroughly by microanalytical data, magnetic susceptibility, molar conductivity, UV-Vis., IR, 1H NMR, 13C NMR and EPR spectral techniques. Their geometry is investigated and established to have square planar geometry. Electronic absorption spectroscopy, cyclic voltammetry and viscosity measurements reveal that the complexes strongly bind to calf thymus DNA via an intercalation mechanism. DNA cleavage efficiency of these complexes is explored by gel electrophoresis, and they are found to endorse the cleavage of pBR322 DNA in presence of oxidant H2O2. These results reveal that all the complexes show better nuclease activity. Moreover, the biological screening against few pathogens reveals that that the complexes have potent biocidal activity than the free ligand.

  3. Biocide tolerance in bacteria.

    PubMed

    Ortega Morente, Elena; Fernández-Fuentes, Miguel Angel; Grande Burgos, Maria José; Abriouel, Hikmate; Pérez Pulido, Rubén; Gálvez, Antonio

    2013-03-01

    Biocides have been employed for centuries, so today a wide range of compounds showing different levels of antimicrobial activity have become available. At the present time, understanding the mechanisms of action of biocides has also become an important issue with the emergence of bacterial tolerance to biocides and the suggestion that biocide and antibiotic resistance in bacteria might be linked. While most of the mechanisms providing antibiotic resistance are agent specific, providing resistance to a single antimicrobial or class of antimicrobial, there are currently numerous examples of efflux systems that accommodate and, thus, provide tolerance to a broad range of structurally unrelated antimicrobials, both antibiotics and biocides. If biocide tolerance becomes increasingly common and it is linked to antibiotic resistance, not only resistant (even multi-resistant) bacteria could be passed along the food chain, but also there are resistance determinants that can spread and lead to the emergence of new resistant microorganisms, which can only be detected and monitored when the building blocks of resistance traits are understood on the molecular level. This review summarizes the main advances reached in understanding the mechanism of action of biocides, the mechanisms of bacterial resistance to both biocides and antibiotics, and the incidence of biocide tolerance in bacteria of concern to human health and the food industry.

  4. Biocide susceptibility of the Burkholderia cepacia complex

    PubMed Central

    Rose, Helen; Baldwin, Adam; Dowson, Christopher G.; Mahenthiralingam, Eshwar

    2009-01-01

    Objectives The Burkholderia cepacia complex (Bcc) species are important opportunistic pathogens with intrinsic antibiotic resistance. They are also well known as contaminants of disinfectants, yet their biocide susceptibility has not been studied in detail. We investigated Bcc biocide susceptibility and correlated it to their taxonomy, antibiotic susceptibility and ability to form biofilms. Methods Genetically distinct Bcc strains belonging to 12 of the defined species were examined. Biocide susceptibility was assessed by (i) broth dilution MIC assays, (ii) agar growth-based MBC screens and (iii) suspension tests. Antibiotic MIC was determined by Etest® strips, and the ability to form biofilms was examined in a 96-well plate assay. Results Biocide susceptibility varied across the Bcc complex with high MIC recorded for chlorhexidine (>100 mg/L), cetylpyridinium chloride (>200 mg/L), triclosan (>500 mg/L), benzalkonium chloride (>400 mg/L) and povidone (>50 000 mg/L). Species-dependent differences were apparent only for cetylpyridinium chloride. There was no correlation between biocide susceptibility and (i) antibiotic susceptibility or (ii) the ability to form biofilms. Biocide MBC was considerably higher than the MIC (chlorhexidine, 6-fold greater; cetylpyridinium chloride, 20-fold greater). Cystic fibrosis outbreak strains (Burkholderia multivorans Glasgow strain and Burkholderia cenocepacia ET12) possessed elevated chlorhexidine resistance, and Bcc bacteria were also shown to remain viable in current commercial biocide formulations. Conclusions Bcc bacteria are resistant to a wide range of biocides and further representatives of this group should be included as reference strains in the development of new anti-infectives and commercial formulations. PMID:19153076

  5. Thermodynamics of emergent magnetic charge screening in artificial spin ice

    PubMed Central

    Farhan, Alan; Scholl, Andreas; Petersen, Charlotte F.; Anghinolfi, Luca; Wuth, Clemens; Dhuey, Scott; Chopdekar, Rajesh V.; Mellado, Paula; Alava, Mikko J.; van Dijken, Sebastiaan

    2016-01-01

    Electric charge screening is a fundamental principle governing the behaviour in a variety of systems in nature. Through reconfiguration of the local environment, the Coulomb attraction between electric charges is decreased, leading, for example, to the creation of polaron states in solids or hydration shells around proteins in water. Here, we directly visualize the real-time creation and decay of screened magnetic charge configurations in a two-dimensional artificial spin ice system, the dipolar dice lattice. By comparing the temperature dependent occurrence of screened and unscreened emergent magnetic charge defects, we determine that screened magnetic charges are indeed a result of local energy reduction and appear as a transient minimum energy state before the system relaxes towards the predicted ground state. These results highlight the important role of emergent magnetic charges in artificial spin ice, giving rise to screened charge excitations and the emergence of exotic low-temperature configurations. PMID:27581972

  6. Biocidal quaternary ammonium resin

    NASA Technical Reports Server (NTRS)

    Janauer, G. E.

    1983-01-01

    Activated carbon (charcoal) and polymeric resin sorbents are widely used in the filtration and treatment of drinking water, mainly to remove dissolved organic and inorganic impurities and to improve the taste. Earlier hopes that activated carbon might "disinfect' water proved to be unfounded. The feasibility of protecting against microbial infestation in charcoal and resin beds such as those to be incorporated into total water reuse systems in spacecraft was investigated. The biocidal effect of IPCD (insoluable polymeric contact disinfectants) in combination with a representative charcoal was assessed. The ion exchange resins (IPCD) were shown to adequately protect charcoal and ion exchange beds.

  7. Characterization of biocide-tolerant bacteria isolated from cheese and dairy small-medium enterprises.

    PubMed

    Fernández Márquez, Ma Luisa; Grande Burgos, Ma José; López Aguayo, Ma Carmen; Pérez Pulido, Rubén; Gálvez, Antonio; Lucas, Rosario

    2017-04-01

    A collection of 120 bacterial isolates from small medium enterprises involved in the production of cow milk and the manufacture of goat cheese were screened for sensitivity to biocides benzalkonium chloride (BC), cetrimide (CT), hexadecylpyridinium chloride (HDP), triclosan (TC), hexachlorophene (CF) and poly-(hexamethylen guanidinium) hydrochloride (PHMG). Nineteen isolates were selected according to biocide tolerance and identified by 16S rDNA sequencing as Lactococcus sp. (6) Enterococcus sp. (1), Lactobacillus sp. (4), Bacillus sp. (1) Escherichia sp. (5), Enterobacter sp. (1) and Helicobacter sp. (1). These were further characterised regarding antimicrobial resistance phenotype and genotype. Several isolates were multiply (3 or more) tolerant to biocides or resistant to antibiotics, but only two Escherichia sp. isolates and Enterobacter sp. were multiply resistant to biocides and antibiotics. Statistical analysis of biocide tolerance and antibiotic resistance revealed significant positive correlations between different biocides and between biocides and antibiotics. The biocide tolerance genes most frequently found were qacEΔ1 and qacA/B. The sulfonamide resistance gene sul1 was found in two Escherichia sp. isolates and in Enterobacter sp., all of which also carried qacEΔ1. Beta-lactam (blaCTX-M, blaPSE) and tetracycline resistance genes [tet(A), tet(C) and tet(D)] were detected. Efflux pump genes acrB and mdfA were found in most Gram-negative isolates. Results from the study suggest that exposure to biocides can indirectly select for antibiotic resistance.

  8. Regenerable biocide delivery unit

    NASA Technical Reports Server (NTRS)

    Colombo, Gerald V.; Jolly, Clifford D.; Sauer, Richard L.

    1991-01-01

    The Microbial Check Valve (MCV) is used on the Space Shuttle to impart an iodine residual to the drinking water to maintain microbial control. Approximately twenty MCV locations have been identified in the Space Station Freedom design, each with a 90-day life. This translates to 2400 replacement units in 30 years of operation. An in situ regeneration concept has been demonstrated that will reduce this replacement requirement to less than 300 units based on data to date. A totally automated system will result in significant savings in crew time, resupply requirements, and replacement costs. An additional feature of the device is the ability to provide a concentrated biocide source (200 mg/liter of I2) that can be used to superiodinate systems routinely or after a microbial upset.

  9. Modified Debye screening potential in a magnetized quantum plasma

    NASA Astrophysics Data System (ADS)

    Salimullah, M.; Hussain, A.; Sara, I.; Murtaza, G.; Shah, H. A.

    2009-07-01

    The effects of quantum mechanical influence and uniform static magnetic field on the Shukla-Nambu-Salimullah potential in an ultracold homogeneous electron-ion Fermi plasma have been examined in detail. It is noticed that the strong quantum effect arising through the Bohm potential and the ion polarization effect can give rise to a new oscillatory behavior of the screening potential beyond the shielding cloud which could explain a new type of possible robust ordered structure formation in the quantum magnetoplasma. However, the magnetic field enhances the Debye length perpendicular to the magnetic field in the weak quantum limit of the quantum plasma.

  10. Risks of Using Antifouling Biocides in Aquaculture

    PubMed Central

    Guardiola, Francisco Antonio; Cuesta, Alberto; Meseguer, José; Esteban, Maria Angeles

    2012-01-01

    Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211®), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms. PMID:22408407

  11. Risks of using antifouling biocides in aquaculture.

    PubMed

    Guardiola, Francisco Antonio; Cuesta, Alberto; Meseguer, José; Esteban, Maria Angeles

    2012-01-01

    Biocides are chemical substances that can deter or kill the microorganisms responsible for biofouling. The rapid expansion of the aquaculture industry is having a significant impact on the marine ecosystems. As the industry expands, it requires the use of more drugs, disinfectants and antifoulant compounds (biocides) to eliminate the microorganisms in the aquaculture facilities. The use of biocides in the aquatic environment, however, has proved to be harmful as it has toxic effects on the marine environment. Organic booster biocides were recently introduced as alternatives to the organotin compounds found in antifouling products after restrictions were imposed on the use of tributyltin (TBT). The replacement products are generally based on copper metal oxides and organic biocides. The biocides that are most commonly used in antifouling paints include chlorothalonil, dichlofluanid, DCOIT (4,5-dichloro-2-n-octyl-4-isothiazolin-3-one, Sea-nine 211(®)), Diuron, Irgarol 1051, TCMS pyridine (2,3,3,6-tetrachloro-4-methylsulfonyl pyridine), zinc pyrithione and Zineb. There are two types of risks associated with the use of biocides in aquaculture: (i) predators and humans may ingest the fish and shellfish that have accumulated in these contaminants and (ii) the development of antibiotic resistance in bacteria. This paper provides an overview of the effects of antifouling (AF) biocides on aquatic organisms. It also provides some insights into the effects and risks of these compounds on non-target organisms.

  12. Chemistry of Durable and Regenerable Biocidal Textiles

    ERIC Educational Resources Information Center

    Gang Sun; Worley, S. Dave

    2005-01-01

    Antimicrobial textiles can be categorized into two groups, biocidal and biostatic materials, according to their functions. Biostatic functions refer to inhibiting growth of microorganisms on textiles and preventing the materials from biodegradation and biocidal materials are able to kill microorganisms, thus eliminating their growth, sterilizing…

  13. Biocidal additives for lubricating/cooling fluids

    SciTech Connect

    Morozova, L.P.; Klyavlina, E.A.; Lebedev, E.V.; Shakhgel'diev, M.A.

    1984-03-01

    This article reports on the synthesis of new biocidal products for the protection of water emulsions of lubricating/cooling fluids (LCFs) against microbiological damage. The new biocides are based on compounds belonging to the classes of oxazolidines and oxazines, and also compounds of these classes but activated by nitro derivatives of aromatic hydrocarbons. Results are presented from evaluations of the biocidal activity of the new products with respect to aerobes, anaerobes, and fungi growing in a 3% emulsion of the widely used LCF Ukrinol-1. The comparative evaluation was based on the optimal biocidal concentration corresponding to the smallest quantity of added biocide to give maximum suppression of the microorganisms in a minimum time, and with the longest period of effectiveness. The lubricating properties of the biocides were evaluated in an emulsion of the Ukrinol-1 LCF is a four-ball tester. It is concluded that the developed biocides are homogeneous, transparent liquids with a specific odor and can be considered as nontoxic to man; they mix readily with components used in formulating LCFs and detergents (sulfonates, oxyethylated alcohols, phenols, polyglycols, fatty acid soaps, etc.). They are readily soluble in water and in oils. Includes 3 tables.

  14. Searching for "environmentally-benign" antifouling biocides.

    PubMed

    Cui, Yan Ting; Teo, Serena L M; Leong, Wai; Chai, Christina L L

    2014-05-26

    As the result of the ecological impacts from the use of tributyltins (TBT) in shipping, environmental legislation for the registration of chemicals for use in the environment has grown to a monumental challenge requiring product dossiers to include information on the environmental fate and behavior of any chemicals. Specifically, persistence, bioaccumulation and toxicity, collectively known as PBT, are properties of concern in the assessment of chemicals. However, existing measurements of PBT properties are a cumbersome and expensive process, and thus not applied in the early stages of the product discovery and development. Inexpensive methods for preliminary PBT screening would minimize risks arising with the subsequent registration of products. In this article, we evaluated the PBT properties of compounds reported to possess anti-fouling properties using QSAR (quantitative structure-activity relationship) prediction programs such as BIOWIN™ (a biodegradation probability program), KOWWIN™ (log octanol-water partition coefficient calculation program) and ECOSAR™ (Ecological Structure Activity Relationship Programme). The analyses identified some small (Mr < 400) synthetic and natural products as potential candidates for environmentally benign biocides. We aim to demonstrate that while these methods of estimation have limitations, when applied with discretion, they are powerful tools useful in the early stages of research for compound selection for further development as anti-foulants.

  15. Chemistry of Durable and Regenerable Biocidal Textiles

    NASA Astrophysics Data System (ADS)

    Sun, Gang; Worley, S. Dave

    2005-01-01

    Unlike the widely used slow-releasing biocidal mechanism now employed in biocidal textiles, a novel regenerable process, based on a regeneration principle and halamine chemistry, has been developed in antimicrobial finishing of textiles. Halamine-modified textile materials demonstrate durable and regenerable antimicrobial functions and execute rapid inactivation of a broad spectrum of microorganisms by contact without yielding drug resistance. The unique properties of the products render them useful materials for medical-use and hygienic textiles. The chemistry of the biocidal materials is be discussed. See Featured Molecules .

  16. Selection of an Alternate Biocide for the ISS Internal Thermal Control System Coolant, Phase 2

    NASA Technical Reports Server (NTRS)

    Wilson, Mark E.; Cole, Harold; Weir, Natalee; Oehler, Bill; Steele, John; Varsik, Jerry; Lukens, Clark

    2004-01-01

    The ISS (International Space Station) ITCS (Internal Thermal Control System) includes two internal coolant loops that utilize an aqueous based coolant for heat transfer. A silver salt biocide had previously been utilized as an additive in the coolant formulation to control the growth and proliferation of microorganisms within the coolant loops. Ground-based and in-flight testing demonstrated that the silver salt was rapidly depleted, and did not act as an effective long-term biocide. Efforts to select an optimal alternate biocide for the ITCS coolant application have been underway and are now in the final stages. An extensive evaluation of biocides was conducted to down-select to several candidates for test trials and was reported on previously. Criteria for that down-select included: the need for safe, non-intrusive implementation and operation in a functioning system; the ability to control existing planktonic and biofilm residing microorganisms; a negligible impact on system-wetted materials of construction; and a negligible reactivity with existing coolant additives. Candidate testing to provide data for the selection of an optimal alternate biocide is now in the final stages. That testing has included rapid biocide effectiveness screening using Biolog MT2 plates to determine minimum inhibitory concentration (amount that will inhibit visible growth of microorganisms), time kill studies to determine the exposure time required to completely eliminate organism growth, materials compatibility exposure evaluations, coolant compatibility studies, and bench-top simulated coolant testing. This paper reports the current status of the effort to select an alternate biocide for the ISS ITCS coolant. The results of various test results to select the optimal candidate are presented.

  17. Antiplaque biocides and bacterial resistance: a review.

    PubMed

    Sreenivasan, Prem; Gaffar, Abdul

    2002-11-01

    Modern dentistry emphasizes the importance of dental plaque control to improve oral health. The use of oral care formulations with antiplaque biocides plays a crucial role in patient-directed approaches for plaque control. The antiplaque efficacies of these formulations have been extensively studied in many long-term clinical studies designed in accordance with well-accepted guidelines. The results from these studies conclusively demonstrate that long-term use of oral care formulations with well-known antiplaque biocides such as chlorhexidine and triclosan reduce supragingival plaque and gingivitis. This review summarizes microbiological results from clinical studies conducted with oral care formulations containing antiplaque biocides. Results from a number of long-term clinical studies conducted under real-life use conditions indicate no adverse alterations in the bacteria found in dental plaque or emergent microbial resistance. Additionally, microbial sampling of dental plaque subsequent to extended use of antiplaque biocides reveals no increase in resistant microflora. Large numbers of common oral bacteria isolated from patients using chlorhexidine indicate no increase in microbial resistance to chlorhexidine or to commonly used antibiotics. The effects of antiplaque biocides containing oral care formulations on dental plaque that exists naturally as a biofilm are examined. These formulations contain biocide, surfactants, polymers and other components that are effective against the biofilm. In summary, the results of studies on the real-life use of oral care formulations with antiplaque biocides show no emergence of resistant microflora or alterations of the oral microbiota, while such formulations have been found to provide the benefits of reducing plaque and gingivitis.

  18. Microwave assisted synthesis, characterization and biocidal activities of some new chelates of carbazole derived Schiff bases of cadmium and tin metals

    NASA Astrophysics Data System (ADS)

    Yadav, Manju; Mishra, Neelima; Sharma, Nutan; Chandra, Sulekh; Kumar, Dinesh

    2014-11-01

    This study is planned to report the advancement of green microwave approach in the fabrication of a new series of biologically potent (N^X, where X = O/S) donor Schiff bases and their cadmium(II) and tin(II) complexes. The ligands and their metal complexes have been characterized in terms of elemental analysis, molar ionic conductance, magnetic moment and spectral (IR, UV-Vis, NMR (1H, 119Sn), FAB-mass, thermal and XRD) data. The data revealed that the ligands coordinated to the metal center via nitrogen and oxygen/sulfur atoms and form an octahedral arrangement of the ligands around central metal atom. All compounds were evaluated for their in vitro antimicrobial activities against two pathogenic bacteria Bacillus subtilis and Escherichia coli and two fungi Aspergillus niger and Aspergillus flavus by standard disc diffusion method. The discs were stored in an incubator at 37 °C. The compounds were dissolved in DMF at 500 and 1000 ppm concentrations for screening biocidal activity. The compounds were dissolved in DMF to get the 100 and 200 ppm concentration of test solutions for screening fungicidal activity. The inhibition zone around each disc was measured (in mm) after 24 h and 96 h for biocidal and fungicidal activities respectively.

  19. Microwave assisted synthesis, characterization and biocidal activities of some new chelates of carbazole derived Schiff bases of cadmium and tin metals.

    PubMed

    Yadav, Manju; Mishra, Neelima; Sharma, Nutan; Chandra, Sulekh; Kumar, Dinesh

    2014-11-11

    This study is planned to report the advancement of green microwave approach in the fabrication of a new series of biologically potent (N^X, where X=O/S) donor Schiff bases and their cadmium(II) and tin(II) complexes. The ligands and their metal complexes have been characterized in terms of elemental analysis, molar ionic conductance, magnetic moment and spectral (IR, UV-Vis, NMR ((1)H, (119)Sn), FAB-mass, thermal and XRD) data. The data revealed that the ligands coordinated to the metal center via nitrogen and oxygen/sulfur atoms and form an octahedral arrangement of the ligands around central metal atom. All compounds were evaluated for their in vitro antimicrobial activities against two pathogenic bacteria Bacillus subtilis and Escherichia coli and two fungi Aspergillus niger and Aspergillus flavus by standard disc diffusion method. The discs were stored in an incubator at 37°C. The compounds were dissolved in DMF at 500 and 1000 ppm concentrations for screening biocidal activity. The compounds were dissolved in DMF to get the 100 and 200 ppm concentration of test solutions for screening fungicidal activity. The inhibition zone around each disc was measured (in mm) after 24 h and 96 h for biocidal and fungicidal activities respectively.

  20. Accidental poisoning with biodiesel preservative biocide

    PubMed Central

    Aslanidis, T; Ourailoglou, V; Boultoukas, E; Giannakou-Peftoulidou, M

    2014-01-01

    Although biodiesel fuels’ use is getting more and more popular, there are only few reports in the literature of poisoning with such agents, and none referring to their preservatives: biocides. We present the management of a 49-year-old Caucasian male who was admitted, after accidental ingestion of biocide solution, in the intensive care unit of a tertiary hospital. In spite of his devastating condition upon arrival to the hospital, he had a remarkable recovery with no local or systemic sequel due to multidisciplinary and early supportive approach of his care. PMID:25336882

  1. The Potential of Antimicrobial Peptides as Biocides

    PubMed Central

    Laverty, Garry; Gorman, Sean P.; Gilmore, Brendan F.

    2011-01-01

    Antimicrobial peptides constitute a diverse class of naturally occurring antimicrobial molecules which have activity against a wide range of pathogenic microorganisms. Antimicrobial peptides are exciting leads in the development of novel biocidal agents at a time when classical antibiotics are under intense pressure from emerging resistance, and the global industry in antibiotic research and development stagnates. This review will examine the potential of antimicrobial peptides, both natural and synthetic, as novel biocidal agents in the battle against multi-drug resistant pathogen infections. PMID:22072905

  2. Biocides: Capturing bugs and bigger markets

    SciTech Connect

    Hairston, D.W.

    1995-10-01

    Deep in the dark interior of cooling water towers, intake streams and purifiers, there is a jungle. Hundreds of thousands of microorganisms dwell in algae and biofilm, breeding mutant and increasingly resistant strains of bacteria. For biocide manufacturers, the imperative is to find better ways to control the proliferation of the microscopic bugs. Some of the most robust demand for biocides is in the cooling water market, particularly as industrial water treatment continues to switch from gaseous chlorine to bromine compounds. The trend toward closed-loop and faster cycles for process water treatment will require more biological control. Biocides are expected to benefit from that trend, but in pulp and paper operations, chlorine dioxide may reap the biggest gains. Also making inroads is an electrolytic system that uses ClO{sub 2} to control microorganisms in cooling towers. Despite growing demand for safe and more-effective biocides in Europe and the US, new product development is stymied by the rigorous and costly process of getting regulatory approval. In the US, EPA registration can cost $5--10 million and take 5 to 10 years.

  3. Competition between Kondo Screening and Indirect Magnetic Exchange in a Quantum Box

    NASA Astrophysics Data System (ADS)

    Schwabe, Andrej; Gütersloh, Daniel; Potthoff, Michael

    2012-12-01

    Nanoscale systems of metal atoms antiferromagnetically exchange coupled to several magnetic impurities are shown to exhibit an unconventional reentrant competition between Kondo screening and indirect magnetic exchange interaction. Depending on the atomic positions of the magnetic moments, the total ground-state spin deviates from predictions of standard Ruderman-Kittel-Kasuya-Yosida perturbation theory. The effect shows up on an energy scale larger than the level width induced by the coupling to the environment and is experimentally accessible by studying magnetic field dependencies.

  4. Quantitative screening of yeast surface-displayed polypeptide libraries by magnetic bead capture.

    PubMed

    Yeung, Yik A; Wittrup, K Dane

    2002-01-01

    Magnetic bead capture is demonstrated here to be a feasible alternative for quantitative screening of favorable mutants from a cell-displayed polypeptide library. Flow cytometric sorting with fluorescent probes has been employed previously for high throughput screening for either novel binders or improved mutants. However, many laboratories do not have ready access to this technology as a result of the limited availability and high cost of cytometers, restricting the use of cell-displayed libraries. Using streptavidin-coated magnetic beads and biotinylated ligands, an alternative approach to cell-based library screening for improved mutants was developed. Magnetic bead capture probability of labeled cells is shown to be closely correlated with the surface ligand density. A single-pass enrichment ratio of 9400 +/- 1800-fold, at the expense of 85 +/- 6% binder losses, is achieved from screening a library that contains one antibody-displaying cell (binder) in 1.1 x 10(5) nondisplaying cells. Additionally, kinetic screening for an initial high affinity to low affinity (7.7-fold lower) mutant ratio of 1:95,000, the magnetic bead capture method attains a single-pass enrichment ratio of 600 +/- 200-fold with a 75 +/- 24% probability of loss for the higher affinity mutant. The observed high loss probabilities can be straightforwardly compensated for by library oversampling, given the inherently parallel nature of the screen. Overall, these results demonstrate that magnetic beads are capable of quantitatively screening for novel binders and improved mutants. The described methods are directly analogous to procedures in common use for phage display and should lower the barriers to entry for use of cell surface display libraries.

  5. Biocides for the Battlefield - Interim Report

    DTIC Science & Technology

    2010-09-24

    for public release; distribution is unlimited. James H . Wynne Materials Chemistry Branch Chemistry Division Preston a. Fulmer Chemical Dynamics and...b. ABSTRACT c. THIS PAGE 18. NUMBER OF PAGES 17. LIMITATION OF ABSTRACT Biocides for the Battlefield—Interim Report James H . Wynne and Preston A...distribution is unlimited. Unclassified Unclassified Unclassified SAR 25 James H . Wynne (202) 404-4010 The ability to disinfect surfaces and manufacture self

  6. Biocidal Wax Composition and Preparation Thereof.

    DTIC Science & Technology

    1985-07-01

    WAX COMPOSITION AND PREPARATION THEREOF 2 3 ABSTRACT OF THE DISCLOSURE 4 A biocidal wax composition for preventing corrosion and 5 biological fouling...13 by marine growth or corrosion . Wooden blocks and piers can be 14 destroyed in a few years if left untreated. Many of the 15 traditional treatments...capability or strength 18 through corrosion and marine growth on their surfaces. 19 One approach to reducing marine growth is coating the sur- 20 face

  7. Efficacy of natural biocide on control of microbial induced corrosion in oil pipelines mediated by Desulfovibrio vulgaris and Desulfovibrio gigas.

    PubMed

    Lavania, Meeta; Sarma, Priyangshu M; Mandal, Ajoy K; Cheema, Simrita; Lal, Banwari

    2011-01-01

    We compared the efficacy of a natural biocide with four chemical tetrakishydroxymethyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, and formaldehyde, glutaraldehyde, to control microbial induced corrosion in oil pipelines. The efficacy of biocides were monitored against Desulfovibrio vulgaris and Desulfovibrio gigas in experimental pipes by measuring cell counts, H2S production, Fe(II) production, production of extracellular polymeric substances and structure of biofilm. The treatment with cow urine had minimum planktonic cell counts of 3 x 10(2) CFU/mL as well as biofilm cell counts of 9 x 10(1) CFU/mL as compared with tetrakishydroxyl methyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, formaldehyde and glutaraldehyde. Sulfide production was the lowest with cow urine (0.08 mmol/L), followed by tetrakishydroxymethyl phosphonium sulfonate 0.72 mmol/L. On day 90 of treatment, Fe(II) production was also found to be the lowest with cow urine. The scanning electron microscopic studies indicated that the biofilm bacteria were killed by cow urine. These results demonstrate the cow urine mediated control of microbially induced corrosion, and this is indicative of its potential as a viable substitute of toxic biocides. To the best of our knowledge, this seems to be the first report which screens possible biocidal activity by cow urine as compared to the most common biocides which oil industry is currently using.

  8. Biocidal packaging for pharmaceuticals, foods, and other perishables.

    PubMed

    Larson, Alyssa M; Klibanov, Alexander M

    2013-01-01

    Many consumer goods must be protected from bacterial and fungal colonization to ensure their integrity and safety. By making these items' packaging biocidal, the interior environment can be preserved from microbial spoilage without altering the products themselves. Herein we briefly review this concept, referred to as active packaging, and discuss existing methods for constructing active packaging systems. They are based on either packaging materials that release biocides or those that are themselves intrinsically biocidal (or biostatic), with numerous variations within each category.

  9. The role of individual defects on the magnetic screening of HTSC films

    NASA Astrophysics Data System (ADS)

    Ruoß, Stephen; Stahl, Claudia; Weigand, Markus; Zahn, Patrick; Bayer, Jonas; Schütz, Gisela; Albrecht, Joachim

    2016-10-01

    The magnetic flux penetration into thin films of high-temperature superconducting YBCO is visualized with high spatial resolution via x-ray microscopy. Therefore superconductors are coated with soft-magnetic CoFeB layers that reproduce the magnetic flux density distribution in an adjacent superconducting film and exhibit at the same time a large XMCD effect. For the first time we present scanning x-ray microscopy in the total electron yield mode using polarized x-rays providing simultaneously structural and magnetic information of the surface with high spatial resolution. Correlating the images of structural and magnetic information the role of individual defects on the magnetic screening capability of the superconductor can be identified.

  10. Modeling of screening currents in coated conductor magnets containing up to 40000 turns

    NASA Astrophysics Data System (ADS)

    Pardo, E.

    2016-08-01

    Screening currents caused by varying magnetic fields degrade the homogeneity and stability of the magnetic fields created by REBCO coated conductor coils. They are responsible for the AC loss; which is also important for other power applications containing windings, such as transformers, motors and generators. Since real magnets contain coils exceeding 10000 turns, accurate modeling tools for this number of turns or above are necessary for magnet design. This article presents a fast numerical method to model coils with no loss of accuracy. We model a 10400-turn coil for its real number of turns and coils of up to 40000 turns with continuous approximation, which introduces negligible errors. The screening currents, the screening current induced field (SCIF) and the AC loss is analyzed in detail. The SCIF is at a maximum at the remnant state with a considerably large value. The instantaneous AC loss for an anisotropic magnetic-field dependent J c is qualitatively different than for a constant J c , although the loss per cycle is similar. Saturation of the magnetization currents at the end pancakes causes the maximum AC loss at the first ramp to increase with J c . The presented modeling tool can accurately calculate the SCIF and AC loss in practical computing times for coils with any number of turns used in real windings, enabling parameter optimization.

  11. Produced water exposure alters bacterial response to biocides.

    PubMed

    Vikram, Amit; Lipus, Daniel; Bibby, Kyle

    2014-11-04

    Microbial activity during the holding and reuse of wastewater from hydraulic fracturing operations, termed produced water, may lead to issues with corrosion, sulfide release, and fouling. Biocides are applied to control biological activity, often with limited efficacy, which is typically attributed to chemical interactions with the produced water. However, it is unknown whether there is a biologically driven mechanism to biocide tolerance in produced water. Here, we demonstrate that produced water exposure results in an enhanced tolerance against the typically used biocide glutaraldehyde and increased susceptibility to the oxidative biocide hypochlorite in a native and a model bacteria and that this altered resistance is due to the salinity of the produced water. In addition, we elucidate the genetic response of the model organism Pseudomonas fluorescens to produced water exposure to provide a mechanistic interpretation of the altered biocide resistance. The RNA-seq data demonstrated the induction of genes involved in osmotic stress, energy production and conversion, membrane integrity, and protein transport following produced water exposure, which facilitates bacterial survival and alters biocide tolerance. Efforts to fundamentally understand biocide resistance mechanisms, which enable the optimization of biocide application, hold significant implications for greening of the fracturing process through encouraging produced water recycling. Specifically, these results suggest the necessity of optimizing biocide application at the level of individual shale plays, rather than historical experience, based upon produced water characteristics and salinity.

  12. Magnetic Charge Organization and Screening in Thermalized Artificial Spin Ice

    NASA Astrophysics Data System (ADS)

    Gilbert, Ian

    2014-03-01

    Artificial spin ice is a material-by-design in which interacting single-domain ferromagnetic nanoislands are used to model Ising spins in frustrated spin systems. Artificial spin ice has proved a useful system in which to directly probe the physics of geometrical frustration, allowing us to better understand materials such as spin ice. Recently, several new experimental techniques have been developed that allow effective thermalization of artificial spin ice. Given the intense interest in magnetic monopole excitations in spin ice materials and artificial spin ice's success in modeling these materials, it should not come as a surprise that interesting monopole physics emerges here as well. The first experimental investigation of thermalized artificial square spin ice determined that the system's monopole-like excitations obeyed a Boltzmann distribution and also found evidence for monopole-antimonopole interactions. Further experiments have implicated these monopole excitations in the growth of ground state domains. Our recent study of artificial kagome spin ice, whose odd-coordinated vertices always possess a net magnetic charge, has revealed a theoretically-predicted magnetic charge ordering transition which has not been previously observed experimentally. We have also investigated the details of magnetic charge interactions in lattices of mixed coordination number. This work was done in collaboration with Sheng Zhang, Cristiano Nisoli, Gia-Wei Chern, Michael Erickson, Liam O'Brien, Chris Leighton, Paul Lammert, Vincent Crespi, and Peter Schiffer. This work was primarily funded by the US Department of Energy, Office of Basic Energy Sciences, Materials Science and Engineering Division, grant no. DE-SC0005313.

  13. Nonlinear dynamics of Josephson vortices in a film screen under dc and ac magnetic fields

    NASA Astrophysics Data System (ADS)

    Sheikhzada, A.; Gurevich, A.

    2014-11-01

    We present detailed numerical simulations of Josephson vortices in a long Josephson junction perpendicular to a thin film screen under strong dc and ac magnetic fields. By solving the sine-Gordon equation, we calculated the threshold magnetic field for penetration of fluxons as a function of frequency, and the power dissipated by oscillating fluxons as functions of the ac field amplitude and frequency. We considered the effects of superimposed ac and dc fields, and a bi-harmonic magnetic field resulting in a vortex ratchet dynamics. The results were used to evaluate the contribution of weak-linked grain boundaries to the nonlinear surface resistance of polycrystalline superconductors under strong electromagnetic fields, particularly thin film screens and resonator cavities.

  14. Hand dermatitis: a focus on allergic contact dermatitis to biocides.

    PubMed

    Maier, Lisa E; Lampel, Heather P; Bhutani, Tina; Jacob, Sharon E

    2009-07-01

    Hand dermatitis is a common disease of the skin resulting in significantly decreased quality of life. Allergic contact dermatitis is a frequent cause of hand dermatitis. Recent studies have revealed that biocides used as preservatives are frequent allergens affecting the hands. This article reviews common biocides implicated in hand dermatitis.

  15. Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens.

    PubMed

    Nardello-Rataj, Véronique; Leclercq, Loïc

    2014-01-01

    Host-guest chemistry is useful for the construction of nanosized objects. Some of the widely used hosts are probably the cyclodextrins (CDs). CDs can form water-soluble complexes with numerous hydrophobic compounds. They have been widespread used in medicine, drug delivery and are of interest for the biocides encapsulation. Indeed, this enables the development of more or less complex systems that release antimicrobial agents with time. In this paper, the general features of CDs and their applications in the field of biocides have been reviewed. As the key point is the formation of biocide-CD inclusion complexes, this review deals with this in depth and the advantages of biocide encapsulation are highlighted throughout several examples from the literature. Finally, some future directions of investigation have been proposed. We hope that scientists studying biocide applications receive inspiration from this review to exploit the opportunities offered by CDs in their respective research areas.

  16. Peracetic acid: A new biocide for industrial water applications

    SciTech Connect

    Kramer, J.F.

    1997-12-01

    Peracetic acid is rapidly cidal at low concentrations against a broad spectrum of microorganisms, including gram-positive and gram-negative bacteria, yeasts, molds, and algae under a wide variety of conditions. It is also effective against anaerobic and spore forming bacteria. Peracetic acid is effective at killing biofilm microorganisms at low concentrations and short contact times. Unlike a number of other biocides, the biocidal activity of peracetic acid is not affected by pH or water hardness and biocidal activity is retained even in the presence of organic matter. For these reasons, peracetic acid is well suited as a biocide in industrial cooling water and papermaking systems. Peracetic acid is compatible with additives commonly used in these systems. Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products, acetic acid, water and oxygen, are innocuous and environmentally acceptable.

  17. Screening of external magnetic perturbation fields due to sheared plasma flow

    NASA Astrophysics Data System (ADS)

    Li, L.; Liu, Y. Q.; Liang, Y.; Wang, N.; Luan, Q.; Zhong, F. C.; Liu, Y.

    2016-09-01

    Within the single fluid resistive magnetohydrodynamic model, systematic toroidal modelling efforts are devoted to investigate the plasma response induced screening of the applied external 3D magnetic field perturbations in the presence of sheared toroidal flow. One particular issue of interest is addressed, when the local flow speed approaches zero at the perturbation rational surface inside the plasma. Subtle screening physics, associated with the favourable averaged toroidal curvature effect (the GGJ effect (Glasser et al 1975 Phys. Fluids 7 875)), is found to play an essential role during slow flow near the rational surface by enhancing the screening at reduced flow. A strong cancellation effect between different terms of Ohm’s law is discovered, leading to different screening physics in the GGJ regime, as compared to that of conventional screening of the typical resistive-inertial regime occurring at faster flow. These modelling results may be applicable to interpret certain mode locking experiments, as well as type-I edge localized mode suppression experiments, with resonant magnetic field perturbations being applied to tokamak plasmas at low input toroidal torque.

  18. Magnetic resonance colonography without bowel cleansing: a prospective cross sectional study in a screening population

    PubMed Central

    Kuehle, Christiane A; Langhorst, Jost; Ladd, Susanne C; Zoepf, Thomas; Nuefer, Michael; Grabellus, Florian; Barkhausen, Joerg; Gerken, Guido; Lauenstein, Thomas C

    2007-01-01

    Background and aim To evaluate the diagnostic accuracy of magnetic resonance colonography (MRC) without bowel cleansing in a screening population and compare the results to colonoscopy as a standard of reference. Methods 315 screening patients, older than 50 years with a normal risk profile for colorectal cancer, were included in this study. For MRC, a tagging agent (5.0% Gastrografin, 1.0% barium sulphate, 0.2% locust bean gum) was ingested with each main meal within 2 days prior to MRC. No bowel cleansing was applied. For the magnetic resonance examination, a rectal water enema was administered. Data collection was based on contrast enhanced T1 weighted images and TrueFISP images. Magnetic resonance data were analysed for image quality and the presence of colorectal lesions. Conventional colonoscopy and histopathological samples served as reference. Results In 4% of all colonic segments, magnetic resonance image quality was insufficient because of untagged faecal material. Adenomatous polyps >5 mm were detected by means of MRC, with a sensitivity of 83.0%. Overall specificity was 90.2% (false positive findings in 19 patients). However, only 16 of 153 lesions <5 mm and 9 of 127 hyperplastic polyps could be visualised on magnetic resonance images. Conclusions Faecal tagging MRC is applicable for screening purposes. It provides good accuracy for the detection of relevant (ie, adenomatous) colorectal lesions >5 mm in a screening population. However, refinements to optimise image quality of faecal tagging are needed. PMID:17341542

  19. Development of a biocidal treatment regime to inhibit biological growths on cultural heritage: BIODAM

    NASA Astrophysics Data System (ADS)

    Young, M. E.; Alakomi, H.-L.; Fortune, I.; Gorbushina, A. A.; Krumbein, W. E.; Maxwell, I.; McCullagh, C.; Robertson, P.; Saarela, M.; Valero, J.; Vendrell, M.

    2008-12-01

    Existing chemical treatments to prevent biological damage to monuments often involve considerable amounts of potentially dangerous and even poisonous biocides. The scientific approach described in this paper aims at a drastic reduction in the concentration of biocide applications by a polyphasic approach of biocides combined with cell permeabilisers, polysaccharide and pigment inhibitors and a photodynamic treatment. A variety of potential agents were screened to determine the most effective combination. Promising compounds were tested under laboratory conditions with cultures of rock deteriorating bacteria, algae, cyanobacteria and fungi. A subsequent field trial involved two sandstone types with natural biofilms. These were treated with multiple combinations of chemicals and exposed to three different climatic conditions. Although treatments proved successful in the laboratory, field trials were inconclusive and further testing will be required to determine the most effective treatment regime. While the most effective combination of chemicals and their application methodology is still being optimised, results to date indicate that this is a promising and effective treatment for the control of a wide variety of potentially damaging organisms colonising stone substrates.

  20. The use of magnetic nanoparticles in thermal therapy monitoring and screening: Localization and imaging (invited)

    NASA Astrophysics Data System (ADS)

    Weaver, John B.

    2012-04-01

    Magnetic nanoparticles have many diagnostic and therapeutic applications. A method termed magnetic spectroscopy of nanoparticle Brownian motion (MSB) was developed to interrogate in vivo the microscopic environment surrounding magnetic nanoparticles. We can monitor several effects that are important in thermal therapy and screening including temperature measurement and the bound state distribution. Here we report on simulations of nanoparticle localization. Measuring the spatial distribution of nanoparticles would allow us to identify ovarian cancer much earlier when it is still curable or monitor thermal therapies more accurately. We demonstrate that with well-designed equipment superior signal to noise ratio (SNR) can be achieved using only two harmonics rather than using all the harmonics containing signal. Alternatively, smaller magnetic field amplitudes can be used to achieve the same SNR. The SNR is improved using fewer harmonics because the noise is limited.

  1. Triclosan as a surrogate for household biocides: an investigation into biocides in aquatic environments of a highly urbanized region.

    PubMed

    Chen, Zhi-Feng; Ying, Guang-Guo; Liu, You-Sheng; Zhang, Qian-Qian; Zhao, Jian-Liang; Liu, Shuang-Shuang; Chen, Jun; Peng, Feng-Jiao; Lai, Hua-Jie; Pan, Chang-Gui

    2014-07-01

    Biocides are widely formulated in household and personal care products. We investigated the distribution and ecological risks of 16 household biocides in aquatic environments of a highly urbanized region in South China, evaluated triclosan as a chemical indicator for this group of household chemicals, and proposed a novel approach to predict the environmental occurrence and fate of these household biocides by using triclosan usage data and a level-III fugacity model. Eleven biocides were quantitatively detected at concentrations up to 264 ± 15.3 ng/L for climbazole in surface water, and up to 5649 ± 748 ng/g for triclocarban in sediment of four rivers in the region. The distribution of biocides in the aquatic environments was significantly correlated with environmental variables such as total nitrogen, total phosphorus and population. Domestic sewage in the region was the dominant pollution source for most biocides such as azole fungicides (fluconazole, climbazole, clotrimazole, ketoconazole, miconazole, and carbendazim) and disinfectants (triclosan and triclocarban). Preliminary risk assessment showed high ecological risks posed by two biocides carbendazim and triclosan in river waters. Mostly important, triclosan was found to be a reliable chemical indicator to surrogate household biocides both in water and sediment based on the correlation analysis. In addition, the fugacity modeling could provide simulated concentrations comparable to the monitoring results. Therefore, with the usage data of the chemical indicator triclosan and correlation formula with other biocides, this model can be applied for predicting the occurrence and fate of various household biocides in a catchment.

  2. Kondo screening of the spin and orbital magnetic moments of Fe impurities in Cu

    NASA Astrophysics Data System (ADS)

    Joly, L.; Kappler, J.-P.; Ohresser, P.; Sainctavit, Ph.; Henry, Y.; Gautier, F.; Schmerber, G.; Kim, D. J.; Goyhenex, C.; Bulou, H.; Bengone, O.; Kavich, J.; Gambardella, P.; Scheurer, F.

    2017-01-01

    We use x-ray magnetic circular dichroism to evidence the effect of correlations on the local impurity magnetic moment in an archetypal Kondo system, namely, a dilute Cu:Fe alloy. Applying the sum rules on the Fe L2 ,3 absorption edges, the evolution of the spin and orbital moments across the Kondo temperature are determined separately. The spin moment presents a crossover from a nearly temperature-independent regime below the Kondo temperature to a paramagneticlike regime above. Conversely, the weak orbital moment shows a temperature-independent behavior in the whole temperature range, suggesting different Kondo screening temperature scales for the spin and orbital moments.

  3. Screening of the Coulomb field in a magnetized electron gas of a quantum cylinder

    SciTech Connect

    Eminov, P. A.

    2009-05-15

    The quantum theory is constructed for screening of the Coulomb field of a point charge in a magnetized electron gas of a quantum cylinder. The asymptotics of the screened potential are calculated for both degenerate and Boltzmann electron gases. It is demonstrated that, in the degenerate case, apart from the known quasi-classical monotonic part, the result contains the quantum oscillating part, which corresponds to Friedel oscillations. The Aharonov-Bohm oscillations of the screened Coulomb interaction of electrons on a cylindrical surface are described analytically. It is shown that the Friedel oscillations can be represented as a superposition of oscillations with different frequencies which are determined by the macroscopic properties of the nanotube.

  4. Structural alerts for estimating the carcinogenicity of pesticides and biocides.

    PubMed

    Devillers, J; Mombelli, E; Samsera, R

    2011-03-01

    More than 20 years ago, Ashby and Tennant showed the interest of structural alerts for the prediction of the carcinogenicity of chemicals. These structural alerts are functional groups or structural features of various sizes that are linked to the level of carcinogenicity of chemicals. Since this pioneering work it has been possible to refine the alerts over time, as more experimental results have become available and additional mechanistic insights have been gained. To date, one of the most advanced lists of structural alerts for evaluating the carcinogenic potential of chemicals is the list proposed by Benigni and Bossa and that is implemented as a rule-based system in Toxtree and in the OECD QSAR Application Toolbox. In order to gain insight into the applicability of this system to the detection of potential carcinogens we screened about 200 pesticides and biocides showing a high structural diversity. Prediction results were compared with experimental data retrieved from an extensive bibliographical review. The prediction correctness was only equal to 60.14%. Attempts were made to analyse the sources of mispredictions.

  5. Searching for “Environmentally-Benign” Antifouling Biocides

    PubMed Central

    Cui, Yan Ting; Teo, Serena L. M.; Leong, Wai; Chai, Christina L. L.

    2014-01-01

    As the result of the ecological impacts from the use of tributyltins (TBT) in shipping, environmental legislation for the registration of chemicals for use in the environment has grown to a monumental challenge requiring product dossiers to include information on the environmental fate and behavior of any chemicals. Specifically, persistence, bioaccumulation and toxicity, collectively known as PBT, are properties of concern in the assessment of chemicals. However, existing measurements of PBT properties are a cumbersome and expensive process, and thus not applied in the early stages of the product discovery and development. Inexpensive methods for preliminary PBT screening would minimize risks arising with the subsequent registration of products. In this article, we evaluated the PBT properties of compounds reported to possess anti-fouling properties using QSAR (quantitative structure-activity relationship) prediction programs such as BIOWIN™ (a biodegradation probability program), KOWWIN™ (log octanol-water partition coefficient calculation program) and ECOSAR™ (Ecological Structure Activity Relationship Programme). The analyses identified some small (Mr < 400) synthetic and natural products as potential candidates for environmentally benign biocides. We aim to demonstrate that while these methods of estimation have limitations, when applied with discretion, they are powerful tools useful in the early stages of research for compound selection for further development as anti-foulants. PMID:24865489

  6. Quality requirements for biocides in the 1990s.

    PubMed

    Weiler, E D; Jayjock, M A; Greenley, D E

    1993-09-01

    Increasing regulatory and product safety standards along with the enhanced expectations of today's consumer public have dramatically changed the manner in which new biocides are researched, developed, and marketed. Potential candidates face ever rising quality hurdles regarding Product Efficacy, Toxicology, Human Health and Environmental Risk Assessment and Risk Management, and, ultimately, Product Stewardship. These pressures have resulted in long lead times for new products with few companies entering into the biocide market. Another resultant trend has been a strong tendency to expand the life cycles of existing products. This report outlines and summarizes recent activity associated with these quality issues and their relationship to the successful marketing of biocides in the future.

  7. Magnetic Alignment of Microelements Containing Cultured Neuronal Networks for High-Throughput Screening.

    PubMed

    Gordon, Kent R; Wang, Yuli; Allbritton, Nancy L; Taylor, Anne Marion

    2015-10-01

    High-throughput screening (HTS) on neurons presents unique difficulties because they are postmitotic, limited in supply, and challenging to harvest from animals or generate from stem cells. These limitations have hindered neurological drug discovery, leaving an unmet need to develop cost-effective technology for HTS using neurons. Traditional screening methods use up to 20,000 neurons per well in 384-well plates. To increase throughput, we use "microraft" arrays, consisting of 1600 square, releasable, paramagnetic, polystyrene microelements (microrafts), each providing a culture surface for 500-700 neurons. These microrafts can be detached from the array and transferred to 384-well plates for HTS; however, they must be centered within wells for automated imaging. Here, we developed a magnet array plate, compatible with HTS fluid-handling systems, to center microrafts within wells. We used finite element analysis to select an effective size of the magnets and confirmed that adjacent magnetic fields do not interfere. We then experimentally tested the plate's centering ability and found a centering efficiency of 100%, compared with 4.35% using a flat magnet. We concluded that microrafts could be centered after settling randomly within the well, overcoming friction, and confirmed these results by centering microrafts containing hippocampal neurons cultured for 8 days.

  8. Regenerable biocide delivery unit, volume 1

    NASA Technical Reports Server (NTRS)

    Atwater, James E.; Wheeler, Richard R., Jr.

    1992-01-01

    The Microbial Check Valve (MCV), which is currently used aboard the Shuttle Orbiter for disinfection of the potable water supply, is an expendable flow-through canister containing iodinated ion exchange resin. Means for extension of MCV life are desirable to avoid resupply penalties. The Phase 1 Regenerable Biocide Delivery Unit program demonstrated the feasibility of regenerating an MCV in situ, using a strong aqueous elemental iodine solution resulting from diversion of the MCV influent to a packed bed containing iodine crystals. In small column tests, eight manual regenerations of an MCV resin were accomplished. The term Regenerative Microbial Check Valve (RMCV) was adopted describing this new technology. The Phase 2 program resulted in the development of a full scale and fully autonomous prototype RMCV, capable of maintaining residual I(sub 2) levels between 2.0 - 4.0 mg/L for prolonged periods. During six months of testing at the Space Station baseline flow rate of 120 cm(sup 3)/min, the prototype RMCV underwent nine regenerations. RMCV life cycle tests, using a variety of influent streams, were conducted over an eighteen month period to determine the useful lives of MCV's incorporating this new technology and to determine ultimate failure mechanisms. MCV life extensions of 130 fold were demonstrated, limited only by the Phase 2 performance period. Based upon this work, it is certain that RMCV units can be developed to provide unattended biocide addition for the thirty year life of Space Station Freedom, or for other longer duration applications such as a Lunar Base or Mars mission. RMCV technology was also demonstrated capable of delivering, on demand, a concentrated aqueous I(sub 2) solution for potential use as a disinfectant during transient episodes of microbial surface contamination, for the control of biofilm formation, or as a preventative measure in systems which are particularly susceptible to the growth of microorganisms.

  9. Encapsulation of biocides by cyclodextrins: toward synergistic effects against pathogens

    PubMed Central

    Nardello-Rataj, Véronique

    2014-01-01

    Summary Host–guest chemistry is useful for the construction of nanosized objects. Some of the widely used hosts are probably the cyclodextrins (CDs). CDs can form water-soluble complexes with numerous hydrophobic compounds. They have been widespread used in medicine, drug delivery and are of interest for the biocides encapsulation. Indeed, this enables the development of more or less complex systems that release antimicrobial agents with time. In this paper, the general features of CDs and their applications in the field of biocides have been reviewed. As the key point is the formation of biocide–CD inclusion complexes, this review deals with this in depth and the advantages of biocide encapsulation are highlighted throughout several examples from the literature. Finally, some future directions of investigation have been proposed. We hope that scientists studying biocide applications receive inspiration from this review to exploit the opportunities offered by CDs in their respective research areas. PMID:25550722

  10. Evolution in the Lab: Biocide Resistance in E.coli.

    ERIC Educational Resources Information Center

    Welden, Charles W.; Hossler, Rex A.

    2003-01-01

    Describes a laboratory experiment on resistance to teach about evolution and issues of misuse of antimicrobial compounds. Investigates Escherichia coli's response to treatment of triclosan, a biocide used in consumer products. (Contains 12 references.) (YDS)

  11. Peracetic acid: A new biocide for industrial water applications

    SciTech Connect

    Kramer, J.F.

    1997-08-01

    Peracetic acid is rapidly cidal at low concentrations against a broad spectrum of microorganisms, including gram-positive and gram-negative bacteria, yeasts, molds, and algae under a wide variety of conditions. It is also effective against anaerobic and spore-forming bacteria. Peracetic acid is effective at killing biofilm microorganisms at low concentrations and short contact times. Unlike a number of other biocides, the biocidal activity of peracetic acid is not affected by pH or water hardness and is retained even in the presence of organic matter. For these reasons, peracetic acid is well-suited as a biocide in industrial cooling water and paper-making systems. It is also compatible with additives commonly used in these systems. Although peracetic acid is a potent biocide, it is unique in that it does not produce toxic byproducts and its decomposition products (acetic acid, water, and oxygen) are innocuous and environmentally acceptable.

  12. Strategies for application of non-oxidizing biocides

    SciTech Connect

    Green, R.F.

    1995-06-01

    The usage of non-oxidizing biocides to control zebra mussels is one of the primary chemical treatment methods available. Due to varying plant configurations several differing strategies are employed for the application of non-oxidizing biocides. These methods include targeted treatments, entire system treatments and forebay treatments. Treatments are coordinated with veliger and mussel settlement data to minimize the frequency of applications. To properly perform a treatment, the necessity of planning and contingencies will be discussed.

  13. Magnetic Microbead Affinity Selection Screening (MagMASS) of Botanical Extracts for Inhibitors of 15-Lipoxygenase.

    PubMed

    Rush, Michael D; Walker, Elisabeth M; Burton, Tristesse; van Breemen, Richard B

    2016-11-23

    To expedite the identification of active natural products in complex mixtures such as botanical extracts, a magnetic microbead affinity selection screening (MagMASS) procedure was developed. This technique utilizes target proteins immobilized on magnetic beads for rapid bioaffinity isolation of ligands from complex mixtures. A MagMASS method was developed and validated for 15-lipoxygenase. As a proof of concept, several North American prairie plants used medicinally by Native Americans were extracted with MeOH and screened. A hit from an extract of Proserpinaca palustris, also known as mermaid weed, was flagged for further characterization using high-resolution tandem mass spectrometry, dereplication, and identification using XCMS online. Through the application of high-resolution product ion tandem mass spectrometry, comparison with natural product databases, and confirmation using standards, the hit was identified as quercitrin, which is a known inhibitor of 15-lipoxygenase. The overall workflow of MagMASS is faster and more amendable to automation than alternative methods designed for screening botanical extracts or complex mixtures of combinatorial libraries.

  14. Adaptive resistance to biocides in Salmonella enterica and Escherichia coli O157 and cross-resistance to antimicrobial agents.

    PubMed

    Braoudaki, M; Hilton, A C

    2004-01-01

    The mechanisms by which bacteria resist killing by antibiotics and biocides are still poorly defined, although repeated exposure to sublethal concentrations of antibacterial agents undoubtedly contributes to their development. This study aimed both to investigate the potential of Salmonella enterica and Escherichia coli O157 for adaptive resistance to commonly used biocides and to determine any cross-resistance to antibiotics. Strains were repeatedly passaged in media containing increasing concentrations of a biocide or antibiotic until adaptive resistance was obtained. A wide panel of antimicrobial agents was then screened by using the adapted strain to determine cross-resistance, if any. Adaptive resistance was readily achieved for both S. enterica and E. coli O157. Cross-resistance in adaptively resistant S. enterica varied with the serotype; Salmonella enterica serovar Enteritidis expressed cross-resistance to chloramphenicol, whereas Salmonella enterica serovar Typhimurium expressed cross-resistance to chlorhexidine. Benzalkonium chloride-resistant Salmonella enterica serovar Virchow showed elevated resistance to chlorhexidine; however, chlorhexidine-resistant Salmonella serovar Virchow did not demonstrate reciprocal cross-resistance to benzalkonium chloride, suggesting specific rather than generic resistance mechanisms. E. coli O157 strains acquired high levels of resistance to triclosan after only two sublethal exposures and, when adapted, repeatedly demonstrated decreased susceptibilities to various antimicrobial agents, including chloramphenicol, erythromycin, imipenem, tetracycline, and trimethoprim, as well as to a number of biocides. These observations raise concern over the indiscriminate and often inappropriate use of biocides, especially triclosan, in situations where they are unnecessary, whereby they may contribute to the development of microbial resistance mechanisms.

  15. Magnetism-assisted modification of screen printed electrode with magnetic multi-walled carbon nanotubes for electrochemical determination of dopamine.

    PubMed

    Zhang, Yong-Mei; Xu, Pei-Li; Zeng, Qiong; Liu, Yi-Ming; Liao, Xun; Hou, Mei-Fang

    2017-05-01

    A simple and sensitive dopamine (DA) electrochemical sensor was fabricated based on magnetism-assisted modification of screen printed electrode (SPE) with magnetic multi-walled carbon nanotubes (mMWCNTs). The mMWCNTs modified electrodes (mMWCNTs/SPE) combines the advantages of SPE and the simultaneous contribution of magnetic nanoparticles (MNPs) and MWCNTs, increasing sensitivity and selectivity of DA detection. The linearity was found between 5μM to 180μM, with the limit of detection (LOD) of 0.43μM. In the mean time, this modified electrode exhibited excellent selectivity for DA detection with almost no interference from ascorbic acid (AA), which co-exists with DA in many bio-samples and causes common interference. Finally, this novel electrode has been applied to determine DA concentration in spiked human blood serum and satisfactory recovery was found in the range of 97.43-102.94% with the RSDs of less than 2.27%. This work developed a sensitive and reliable electrochemical analytical method based on mMWCNTs/SPE, which exhibits great potential for diagnosis of the diseases related to DA.

  16. Material screening metrics and optimal performance of an active magnetic regenerator

    NASA Astrophysics Data System (ADS)

    Niknia, I.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Teyber, R.; Rowe, A.

    2017-02-01

    A variety of metrics to rank the magnetocaloric materials can be found in the literature, but a quantitative assessment showing their efficacy has not been reported. A numerical model of an active magnetic regenerator cycle is used to assess the predictive ability of a set of material metrics. The performance of eight cases of known magnetocaloric material (including first order MnFeP1-xAsx and second order materials Gd, GdDy, Tb), and 15 cases of hypothetical materials are considered. Using a fixed regenerator matrix geometry, magnetic field, and flow waveforms, the maximum exergetic cooling power of each material is identified. Several material screening metrics such as relative cooling power (RCP) are tested and a linear correlation is found between maximum RCP and the maximum exergetic cooling power. The sensitivity of performance to variations in the hot side and cold side temperatures from the conditions giving maximum exergetic power are determined.

  17. Biocidal textiles can help fight nosocomial infections.

    PubMed

    Borkow, Gadi; Gabbay, Jeffrey

    2008-01-01

    The rates of nosocomial infections, especially by those caused by antibiotic resistant bacteria, are increasing alarmingly over the globe. Although more rigorous infection control measures are being implemented, it is clear that the current modalities to reduce nosocomial infections are not sufficient. Textiles are an excellent substrate for bacterial growth under appropriate moisture and temperature conditions. Patients shed bacteria and contaminate their pyjamas and sheets. The temperature and humidity between the patients and the bed are appropriate conditions allowing for effective bacterial proliferation. Several studies have found that personnel in contact with contaminated textiles were the source of transmission of the micro-organisms to susceptible patients. Furthermore, it has been reported that bed making in hospitals releases large quantities of micro-organisms into the air, which contaminate the immediate and non-immediate surroundings. Contaminated textiles in hospitals can thus be an important source of microbes contributing to endogenous, indirect-contact, and aerosol transmission of nosocomial related pathogens. We hypothesize that the use of antimicrobial textiles, especially in those textiles that are in close contact with the patients, may significantly reduce bioburden in clinical settings and consequently reduce the risk of nosocomial infections. These textiles should possess broad spectrum biocidal properties. They should be safe for use and highly effective against antibiotic resistant micro-organisms, including those that are commonly involved in hospital-acquired infections, and they should not permit the development of resistant micro-organisms to the active compound.

  18. Preparation, bioactivity, and application of novel biocidal materials

    NASA Astrophysics Data System (ADS)

    Wu, Rong

    In this study, several novel N-halamine precursors were synthesized. These surface coupling agents were bonded to the surfaces of cotton fabric, cotton gauze, paper, glass, and sand. Once they were activated using household bleach, the surfaces and materials became biocidal. Possible uses for the biocidal cotton are in protective garments for hospital personnel and those who must fight against bioterrorism. The treated cotton gauze may be used to make an antimicrobial mask to stop infective pathogen transcontamination. Biocidal sand has the potential to be used as a disinfectant in a filter for wastewater or municipal water treatment. In fact, the N-halamine siloxanes can be applied to many other surfaces. The results of biocidal efficacy of some of the treated surfaces will be presented in this study. Several new hydantoinyl diols and quaternary ammonium hydantoinyl diols were prepared in this work also. They were copolymerized with commercial water borne acrylic polyol and commercial isocyanate to form polyurethane coatings. The biocidal polyurethane coatings were produced after activation by chlorination. Those diols also reacted with a two-component epoxy paint to render the paint antimicrobial. Several novel biocidal polymeric resins were synthesized by attachment of N-halamine moieties to the commercial polymer supported beads such as Merrifield resin and Amberlite IRA-67 ionic resin. The Merrifield resin and Amberlite IRA-67 ionic resin also were grafted with N-halamine functionality as well as with the N,N-dimethyl-dodecylamine moiety via 1,2-dichloroethane. Finally, several quaternary ammonium N-halamine polymers were prepared. Direct copolymerization of (triethoxysilyl)propyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro-[4,5]-decane-2,4-dione (TTDD-Si), or 3-(trimethoxysilyl)propyl-5,5-dimethylhydantoin (BA-1 ') with 3-(trimethoxysilylpropyl)dimethyloctadecyl ammonium chloride (DC 5700) produced dual functionality and water soluble biocidal materials and

  19. [Analysis of Cost-effectiveness of screening for breast cancer with conventional mammography, digital and magnetic resonance imaging].

    PubMed

    Peregrino, Antonio Augusto de Freitas; Vianna, Cid Manso de Mello; de Almeida, Carlos Eduardo Veloso; Gonzáles, Gabriela Bittencourt; Machado, Samara Cristina Ferreira; Costa e Silva, Frances Valéria; Rodrigues, Marcus Paulo da Silva

    2012-01-01

    A cost-effectiveness analysis was conducted in screening for breast cancer. The use of conventional mammography, digital and magnetic resonance imaging were compared with natural disease history as a baseline. A Markov model projected breast cancer in a group of 100,000 women for a 30 year period, with screening every two years. Four distinct scenarios were modeled: (1) the natural history of breast cancer, as a baseline, (2) conventional film mammography, (3) digital mammography and (4) magnetic resonance imaging. The costs of the scenarios modeled ranged from R$ 194.216,68 for natural history, to R$ 48.614.338,31, for screening with magnetic resonance imaging. The difference in effectiveness between the interventions ranged from 300 to 78.000 years of life gained in the cohort. The ratio of incremental cost-effectiveness in terms of cost per life-year gains, conventional mammographic screening has produced an extra year for R$ 13.573,07. The ICER of magnetic resonance imaging was R$ 2.904.328,88, compared to no screening. In conclusion, it is more cost-effective to perform the screening with conventional mammography than other technological interventions.

  20. Importance of porins for biocide efficacy against Mycobacterium smegmatis.

    PubMed

    Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

    2011-05-01

    Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N'-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides.

  1. Importance of Porins for Biocide Efficacy against Mycobacterium smegmatis▿

    PubMed Central

    Frenzel, Elrike; Schmidt, Stefan; Niederweis, Michael; Steinhauer, Katrin

    2011-01-01

    Mycobacteria are among the microorganisms least susceptible to biocides but cause devastating diseases, such as tuberculosis, and increasingly opportunistic infections. The exceptional resistance of mycobacteria to toxic solutes is due to an unusual outer membrane, which acts as an efficient permeability barrier, in synergy with other resistance mechanisms. Porins are channel-forming proteins in the outer membrane of mycobacteria. In this study we used the alamarBlue assay to show that the deletion of Msp porins in isogenic mutants increased the resistance of Mycobacterium smegmatis to isothiazolinones (methylchloroisothiazolinone [MCI]/methylisothiazolinone [MI] and octylisothiazolinone [2-n-octyl-4-isothiazolin-3-one; OIT]), formaldehyde-releasing biocides {hexahydrotriazine [1,3,5-tris (2-hydroxyethyl)-hexahydrotriazine; HHT] and methylenbisoxazolidine [N,N′-methylene-bis-5-(methyloxazolidine); MBO]}, and the lipophilic biocides polyhexamethylene biguanide and octenidine dihydrochloride 2- to 16-fold. Furthermore, the susceptibility of the porin triple mutant against a complex disinfectant was decreased 8-fold compared to wild-type (wt) M. smegmatis. Efficacy testing in the quantitative suspension test EN 14348 revealed 100-fold improved survival of the porin mutant in the presence of this biocide. These findings underline the importance of porins for the susceptibility of M. smegmatis to biocides. PMID:21398489

  2. Modelling inorganic biocide emission from treated wood in water.

    PubMed

    Tiruta-Barna, Ligia; Schiopu, Nicoleta

    2011-09-15

    The objective of this work is to develop a chemical model for explaining the leaching behaviour of inorganic biocides from treated wood. The standard leaching test XP CEN/TS14429 was applied to a commercial construction material made of treated Pinus sylvestris (Copper Boron Azole preservative). The experimental results were used for developing a chemical model under PHREEQC(®) (a geochemical software, with LLNL, MINTEQ data bases) by considering the released species detected in the eluates: main biocides Cu and B, other trace biocides (Cr and Zn), other elements like Ca, K, Cl, SO(4)(-2), dissolved organic matter (DOC). The model is based on chemical phenomena at liquid/solid interfaces (complexation, ion exchange and hydrolysis) and is satisfactory for the leaching behaviour representation. The simulation results confronted with the experiments confirmed the hypotheses of: (1) biocide fixation by surface complexation reactions with wood specific sites (carboxyl and phenol for Cu, Zn, Cr(III), aliphatic hydroxyl for B, ion exchange to a lesser extent) and (2) biocide mobilisation by extractives (DOC) coming from the wood. The maximum of Cu, Cr(III) and Zn fixation occurred at neutral pH (including the natural pH of wood), while B fixation was favoured at alkaline pH.

  3. The dam breakage of Baia Mare??a pilot study of magnetic screening

    NASA Astrophysics Data System (ADS)

    Wehland, F.; Panaiotu, C.; Appel, E.; Hoffmann, V.; Jordanova, D.; Jordanova, N.; Denut, I.

    Magnetic screening in the area of Baia Mare (Romania) was carried out in June 2000 in order to detect the degree of environmental pollution and to test the applicability of this method in this area. With a long tradition of mining activities, a gradual pollution of soil, air and rivers took place continuously in addition to smaller accidents in this area until the dam breakage on the 30.1.2000. During this accident, about 100,000 m 3 of mud containing cyanide and heavy metals leaked out and moved over fields and through a village into the river system of Lapûs, Someş, Tisza and Danube. Initial magnetic monitoring carried out during the translocation of the polluted waters along the Bulgarian part of the Danube revealed the effectiveness of the method for a proper and fast identification of pollution both in time and space even at remote distances from the source. For the later pilot project magnetic ( χ) screening was performed using a portable Bartington MS2 kappameter with a D-loop sensor. In addition fine-grained material (<0.5 mm) was sampled from the fields and river sediments and measured in the laboratory using a MS2 B-sensor. The results of the collected samples show a clear decrease in χ with increasing distance from the dams and mining areas in a regional and local scale, while the results gained by the MS2-D strongly depend on the nature of the ground. The dynamic geological setting around Baia Mare (fluvial sediments and valley fills), produces a heterogeneous background signal. A continuous monitoring system controlling the basic conditions could overcome these limitations.

  4. Assessment of Rock Magnetic Parameters for Fly Ash Pollution Screening in Topsoil of the Deccan Trap Basalt Area, India

    NASA Astrophysics Data System (ADS)

    Blaha, U.; Basavaiah, N.; Das, P. K.; Deenadayalan, K.

    2012-04-01

    Rock magnetic parameters of highly magnetic topsoil of the Deccan Trap basalt area are evaluated for their suitability for efficient environmental magnetic pollution screening. Parameters, such as magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (κ fd%), anhysteretic remanent magnetization (ARM), saturation isothermal remanent magnetization (SIRM), soft isothermal remanent magnetization (Soft IRM), as well as thermo-magnetic analysis (κ-T) are compared and assessed for best depiction of topsoil contamination due to ash deposition around the Nashik thermal power station (NTPS). Fifty-five topsoil samples, collected along north-south and west-east stretching transects of 24 km length, are the basis for evaluation of the specific ash distribution pattern around the plant and its adjacent ash pond. Similar decline of the magnetic signals with increasing distance from the point source is observed in the concentration dependent magnetic parameters and can be modeled. The magnetic grain size parameters instead reveal increasing trends with increasing distance. Verwey-transition and Hopkinson peak obtained from κ-T analyses demonstrate to be important parameters to prove fly ash accumulation in soils of basaltic origin. The importance of magnetic parameters for indirect tracing of pollutants, such as heavy metals, is shown by Pb, Zn and Cu data, revealing similar distribution pattern as obtained from the concentration dependent magnetic parameters. Confirmation of the presence of a very high amount of ash particles in the vicinity of the NTPS and a low number of particles in more distant areas is provided by scanning electron microscopy (SEM) on quantitatively extracted magnetic particles at 5.5 km and 11.9 km distance in eastern direction. The investigation demonstrates that the majority of the rock magnetic parameters has the potential to be successfully applied in environmental magnetic studies in areas with high magnetic background

  5. Biocidal Inactivation of Lactococcus lactis Bacteriophages: Efficacy and Targets of Commonly Used Sanitizers.

    PubMed

    Hayes, Stephen; Murphy, James; Mahony, Jennifer; Lugli, Gabriele A; Ventura, Marco; Noben, Jean-Paul; Franz, Charles M A P; Neve, Horst; Nauta, Arjen; Van Sinderen, Douwe

    2017-01-01

    Lactococcus lactis strains, being intensely used in the dairy industry, are particularly vulnerable to members of the so-called 936 group of phages. Sanitization and disinfection using purpose-made biocidal solutions is a critical step in controlling phage contamination in such dairy processing plants. The susceptibility of 36 936 group phages to biocidal treatments was examined using 14 biocides and commercially available sanitizers. The targets of a number of these biocides were investigated by means of electron microscopic and proteomic analyses. The results from this study highlight significant variations in phage resistance to biocides among 936 phages. Furthermore, rather than possessing resistance to specific biocides or biocide types, biocide-resistant phages tend to possess a broad tolerance to multiple classes of antimicrobial compounds.

  6. Biocidal Inactivation of Lactococcus lactis Bacteriophages: Efficacy and Targets of Commonly Used Sanitizers

    PubMed Central

    Hayes, Stephen; Murphy, James; Mahony, Jennifer; Lugli, Gabriele A.; Ventura, Marco; Noben, Jean-Paul; Franz, Charles M. A. P.; Neve, Horst; Nauta, Arjen; Van Sinderen, Douwe

    2017-01-01

    Lactococcus lactis strains, being intensely used in the dairy industry, are particularly vulnerable to members of the so-called 936 group of phages. Sanitization and disinfection using purpose-made biocidal solutions is a critical step in controlling phage contamination in such dairy processing plants. The susceptibility of 36 936 group phages to biocidal treatments was examined using 14 biocides and commercially available sanitizers. The targets of a number of these biocides were investigated by means of electron microscopic and proteomic analyses. The results from this study highlight significant variations in phage resistance to biocides among 936 phages. Furthermore, rather than possessing resistance to specific biocides or biocide types, biocide-resistant phages tend to possess a broad tolerance to multiple classes of antimicrobial compounds. PMID:28210242

  7. Optimization of the Magnetic Recovery of Hits from One-Bead-One-Compound Library Screens.

    PubMed

    Mendes, Kimberly; Ndungu, J M; Clark, Lorraine F; Kodadek, Thomas

    2015-09-14

    On-bead screening of one-bead-one-compound (OBOC) libraries is a useful procedure for the identification of protein ligands. An important aspect of this experiment is the method by which beads that bind the target protein are separated from those that do not. Ideally, such a method would be rapid and convenient and result in the isolation of 100% of the "hits" with no false positives (beads that display compounds that are not good ligands for the target). We introduced a technique in which beads that have bound a labeled target protein can be magnetized, thus allowing their convenient isolation ( Astle et al. Chem. Biol. 2010 , 17 , 38 - 45 ). However, recent work in our laboratory and others has shown that magnetic hit recovery can result in the isolation of large numbers of false positives and has also suggested that many true hit beads are missed. In this study, we employ a well-defined model system to examine the efficiency of various magnetic hit isolation protocols. We show that the choice of reagents and the particular operations employed are critical for optimal results.

  8. Polyacrylate-water partitioning of biocidal compounds: enhancing the understanding of biocide partitioning between render and water.

    PubMed

    Bollmann, Ulla E; Ou, Yi; Mayer, Philipp; Trapp, Stefan; Bester, Kai

    2015-01-01

    In recent years, the application of polymer-based renders and paints for façade coatings of buildings has risen enormously due to the increased mounting of thermal insulation systems. These materials are commonly equipped with biocides - algaecides, fungicides, and bactericides - to protect the materials from biological deterioration. However, the biocides need to be present in the water phase in order to be active and, hence, they are flushed of the material by rain water. In order to increase the knowledge about the partitioning of biocides from render into the water phase, partition constants between the polymer - in this case polyacrylate - and water were studied using glass fibre filters coated with polyacrylate. The polyacrylate-water partition constants (logKAcW) of ten biocides used in construction material varied between 1.66 (isoproturon) and 3.57 (dichloro-N-octylisothiazolinone). The correlation of the polyacrylate-water partition constants with the octanol-water partition constants is significant, but the polyacrylate-water partition constants were predominantly below octanol-water partition constants (Kow). The comparison with render-water distribution constants showed that estimating the leaching of biocides from render based on polymer-water partitioning is a useful and practical tool.

  9. Clinical value of whole-body magnetic resonance imaging in health screening of general adult population

    PubMed Central

    Tarnoki, David Laszlo; Tarnoki, Adam Domonkos; Richter, Antje; Karlinger, Kinga; Berczi, Viktor; Pickuth, Dirk

    2015-01-01

    Background Whole-body magnetic resonance imaging (WB-MRI) and angiography (WB-MRA) has become increasingly popular in population-based research. We evaluated retrospectively the frequency of potentially relevant incidental findings throughout the body. Materials and methods 22 highly health-conscious managers (18 men, mean age 47±9 years) underwent WB-MRI and WB-MRA between March 2012 and September 2013 on a Discovery MR750w wide bore 3 Tesla device (GE Healthcare) using T1 weighted, short tau inversion recovery (STIR) and diffusion weighted imaging (DWI) acquisitions according to a standardized protocol. Results A suspicious (pararectal) malignancy was detected in one patient which was confirmed by an endorectal sonography. Incidental findings were described in 20 subjects, including hydrocele (11 patients), benign bony lesion (7 patients) and non-specific lymph nodes (5 patients). Further investigations were recommended in 68% (ultrasound: 36%, computed tomography: 28%, mammography: 9%, additional MRI: 9%). WB-MRA were negative in 16 subjects. Vascular normal variations were reported in 23%, and a 40% left proximal common carotid artery stenosis were described in one subject. Conclusions WB-MRI and MRA lead to the detection of clinically relevant diseases and unexpected findings in a cohort of healthy adults that require further imaging or surveillance in 68%. WB-MR imaging may play a paramount role in health screening, especially in the future generation of (epi)genetic based screening of malignant and atherosclerotic disorders. Our study is the first which involved a highly selected patient group using a high field 3-T wide bore magnet system with T1, STIR, MRA and whole-body DWI acquisitions as well. PMID:25810696

  10. Magnetic Screening Of Wires & Other Resistive Sheath Structure In The Sanford Effect Range With New Conductivities

    NASA Astrophysics Data System (ADS)

    Morse, R. L.; Carroll, D. E.

    2000-03-01

    Because of array stability interest, individual Al wires in the range[1] r=6 to 12mum & Imax=8e4 to 1.6e5 Amp are studied by simulation with ALEGRA and analysis, using I(t) forms of the Sandia Saturn generator w,w/o pre-pulses & qualitatively improved conductivities(sig)[2]. Radial motion of expanded wires is found dominated by resistive quasi-static(RQS) magnetic field behavior(skin depths exceeding dimensions) because sig is greatly reduced by the Mott transition, giving approximately Ez(r)=const. Then J(r) & Joule heating ~sig(r), & wire coronas are first cooled by expansion & then heated relative to cores, first because sig/Cv*rho is larger and then unstably thru sig ~T^3/2 at low rho. Jmax moves from core to corona, largely SCREENING Bth from cores, integral sig*dAz increases, & voltage falls. A thin surface tamper of insulator reduces screening & voltage fall. Nearly hydrostatic balance with RQS JxB forces is seen except when rapidly rising I(t) recompresses wires. Collective resistivity[3] also occurs in the low rho corona tips. [1]Sanford et.al. PRL 16Dec96 [2]Desjarlais BulAPS Nov99 [3]Forslund et.al. PF Jul72

  11. Impurity screening and stability of Fermi arcs against Coulomb and magnetic scattering in a Weyl monopnictide

    NASA Astrophysics Data System (ADS)

    Sessi, Paolo; Sun, Yan; Bathon, Thomas; Glott, Florian; Li, Zhilin; Chen, Hongxiang; Guo, Liwei; Chen, Xiaolong; Schmidt, Marcus; Felser, Claudia; Yan, Binghai; Bode, Matthias

    2017-01-01

    We present a quasiparticle interference study of clean and Mn surface-doped TaAs, a prototypical Weyl semimetal, to test the screening properties as well as the stability of Fermi arcs against Coulomb and magnetic scattering. Contrary to topological insulators, the impurities are effectively screened in Weyl semimetals. The adatoms significantly enhance the strength of the signal such that theoretical predictions on the potential impact of Fermi arcs can be unambiguously scrutinized. Our analysis reveals the existence of three extremely short, previously unknown scattering vectors. Comparison with theory traces them back to scattering events between large parallel segments of spin-split trivial states, strongly limiting their coherence. In sharp contrast to previous work [R. Batabyal et al., Sci. Adv. 2, e1600709 (2016), 10.1126/sciadv.1600709], where similar but weaker subtle modulations were interpreted as evidence of quasiparticle interference originating from Femi arcs, we can safely exclude this being the case. Overall, our results indicate that intra- as well as inter-Fermi arc scattering are strongly suppressed and may explain why—in spite of their complex multiband structure—transport measurements show signatures of topological states in Weyl monopnictides.

  12. Prion protein-coated magnetic beads: Synthesis, characterization and development of a new ligands screening method☆

    PubMed Central

    de Moraes, Marcela Cristina; Santos, Juliana Bosco; dos Anjos, Daniel Meira; Rangel, Luciana Pereira; Vieira, Tuane Cristine Ramos Gonçalves; Moaddel, Ruin; da Silva, Jerson Lima

    2016-01-01

    Prion diseases are characterized by protein aggregation and neurodegeneration. Conversion of the native prion protein (PrPC) into the abnormal scrapie PrP isoform (PrPSc), which undergoes aggregation and can eventually form amyloid fibrils, is a critical step leading to the characteristic path morphological hallmark of these diseases. However, the mechanism of conversion remains unclear. It is known that ligands can act as cofactors or inhibitors in the conversion mechanism of PrPC into PrPSc. Within this context, herein, we describe the immobilization of PrPC onto the surface of magnetic beads and the morphological characterization of PrPC-coated beads by fluorescence confocal microscopy. PrPC-coated magnetic beads were used to identify ligands from a mixture of compounds, which were monitored by UHPLC–ESI-MS/MS. This affinity-based method allowed the isolation of the anti-prion compound quinacrine, an inhibitor of PrP aggregation. The results indicate that this approach can be applied to not only “fish” for anti-prion compounds from complex matrixes, but also to screening for and identify possible cellular cofactors involved in the deflagration of prion diseases. PMID:25576041

  13. Spin noise and magnetic screening of impurities in a BCS superconductor

    NASA Astrophysics Data System (ADS)

    Le Dall, Matthias; da Silva, Luis G. G. V. Dias; de Sousa, Rogério

    The coupling of a localized impurity to a BCS superconductor (SC) leads to the formation of impurity Cooper-pairs via the proximity effect, generating two bound states within the SC energy gap, the so-called Yu-Rusinov-Shiba (YSR) states. They are similar to the Andreev Bound States that originate from Andreev reflection, e.g. when the impurity is hosted in a Josephson junction, and are known to produce sharp sub-gap resonances in charge noise [de Sousa et al., PRB 2009], providing a natural explanation for the observation of microresonators in superconducting devices [Simmonds et al., PRL 2004]. Here we present a theory for the spin noise generated by magnetic impurities in a SC, and discuss the impact of the Shiba states on models of flux noise in superconducting qubits. We use a combination of analytical methods and the numerical renormalization group technique to calculate the spin noise of an Anderson impurity in a SC, unveiling the competition between the proximity effect and Kondo correlations. Both mechanisms produce magnetic screening and a corresponding reduction in spin noise, giving rise to new insights on the kinds of impurities that are responsible for the observed 1 /fα flux noise in superconducting circuits. This research is supported by NSERC CRD/478366-2015.

  14. Magnetic induction imaging with optical atomic magnetometers: towards applications to screening and surveillance

    NASA Astrophysics Data System (ADS)

    Marmugi, Luca; Hussain, Sarah; Deans, Cameron; Renzoni, Ferruccio

    2015-10-01

    We propose a new approach, based on optical atomic magnetometers and magnetic induction tomography (MIT), for remote and non-invasive detection of conductive targets. Atomic magnetometers overcome the main limitations of conventional MIT instrumentation, in particular their poor low-frequency sensitivity, their large size and their limited scalability. Moreover, atomic magnetometers have been proven to reach extremely high sensitivities, with an improvement of up to 7 orders of magnitude in the 50 MHz to DC band, with respect to a standard pick-up coil of the same size. In the present scheme, an oscillating magnetic field induces eddy currents in a conductive target and laser-pumped atomic magnetometers, either stand-alone or in an array, detect the response of the objects. A phase-sensitive detection scheme rejects the background, allowing remote detection of the secondary field and, thus, mapping of objects, hidden in cargos, underwater or underground. The potential for extreme sensitivity, miniaturization, dynamic range and array operation paves the way to a new generation of non-invasive, active detectors for surveillance, as well as for real-time cargo screening.

  15. Linking the Physicochemical Properities of Titania with Its Biocidal Properities

    EPA Science Inventory

    LINKING THE PHYSICOCHEMICAL PROPERTIES OF TITANIA WITH ITS BIOCIDAL PROPERTIES. C. Han1, L. Putvin2, M. Pelaez1, H. Zamankhan3, H. Choi3, D. Betancourt4a, D. Dionysiou1. B. Veronesi4b, 1 Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati...

  16. INVESTIGATION OF GAS-PHASE OZONE AS A POTENTIAL BIOCIDE

    EPA Science Inventory

    The paper presents data on the effect of ozone on both vegetative and spore-forming fungi as well as on spore-forming bacteria. (NOTE: Despite the wide use of ozone generators in indoor air cleaning, there is little research data on ozone's biocidal activity in the gas phase.) Dr...

  17. The role of acoustic screens in distribution of technogenic magnetic particles and chemical pollution in roadside soil

    NASA Astrophysics Data System (ADS)

    Wawer, Małgorzata; Magiera, Tadeusz; Szuszkiewicz, Marcin

    2015-04-01

    Roads constructed nowadays should by all means be functional for their motorized users but at the same time their effect on the environment ought to be limited to the minimum. Despite the existence of various methods for preventing from negative influence of roads on the environment, there is still lack of adequate techniques to monitor and reduce the spreading of roadside pollution in the air and soils. The aim of the study was to assess the influence of acoustic screens on spreading and deposition of solid pollutants deriving from car emissions, based on their quantitative and qualitative analysis. During this study, measurements of magnetic susceptibility and analyses of heavy metals as well as Pt and Rh contents in soil and plant samples (Taraxacum officinale, Plantago major, Parthenocissus quinquefolia) collected near different kinds of acoustic screens ("green walls", Plexiglass, sawdust concrete, steel panels and earth embankments) have been done. Previous investigations showed showed that most of traffic emission is deposited in the close vicinity of the roads (up to 10 m) and the level of contamination decreased with increasing distance from the road edge. However, the results of this project indicate that, in the area where the acoustic screens are located, this distribution is disturbed and the additional enrichment of heavy metals in soil about 10 - 15 m behind screens is observed. Spatial distribution of heavy metal contents in soil samples corresponds to its magnetic susceptibility values. High contents of Fe, Zn, Mn and Pb was observed next to acoustic screens made of sawdust concrete and steel panels. Additionally, concentration of Zn in soil samples collected close to these screens exceeded threshold value. Analyses of plants showed that the highest content of examined elements and highest values of magnetic susceptibility were recorded near road edge. What is more, samples of Parthenocissus quinquefolia collected at height 0.2 m were characterized

  18. Modelling biofilm-induced formation damage and biocide treatment in subsurface geosystems

    PubMed Central

    Ezeuko, C C; Sen, A; Gates, I D

    2013-01-01

    Biofilm growth in subsurface porous media, and its treatment with biocides (antimicrobial agents), involves a complex interaction of biogeochemical processes which provide non-trivial mathematical modelling challenges. Although there are literature reports of mathematical models to evaluate biofilm tolerance to biocides, none of these models have investigated biocide treatment of biofilms growing in interconnected porous media with flow. In this paper, we present a numerical investigation using a pore network model of biofilm growth, formation damage and biocide treatment. The model includes three phases (aqueous, adsorbed biofilm, and solid matrix), a single growth-limiting nutrient and a single biocide dissolved in the water. Biofilm is assumed to contain a single species of microbe, in which each cell can be a viable persister, a viable non-persister, or non-viable (dead). Persisters describe small subpopulation of cells which are tolerant to biocide treatment. Biofilm tolerance to biocide treatment is regulated by persister cells and includes ‘innate’ and ‘biocide-induced’ factors. Simulations demonstrate that biofilm tolerance to biocides can increase with biofilm maturity, and that biocide treatment alone does not reverse biofilm-induced formation damage. Also, a successful application of biological permeability conformance treatment involving geologic layers with flow communication is more complicated than simply engineering the attachment of biofilm-forming cells at desired sites. PMID:23164434

  19. New approaches to biocide effectiveness monitoring using on-site biocide active analysis, ATP analysis, and on-line dosage/monitoring control

    SciTech Connect

    Borchardt, S.A.; Wetegrove, R.L.; Martens, J.D.

    1997-09-01

    Accurate monitoring and control of antimicrobial agents (biocides) are necessary to maintain optimum performance of industrial water systems. Evaluation of many biocides on-site is often difficult due to a lack of accurate field methods. For many non-oxidizing biocides, no field methods are available. The use of a bioluminescence bioassay allows on-site measurement of actual effective toxicant. This technology is based on a bioluminescence bioassay that measures the decrease in light output of a specific bacterium over a given time period in the presence of a toxicant. This response can be accurately correlated to the concentration of toxicant present. This system can also be used to monitor the response of microbiological populations to treatment programs by monitoring shifts in ATP levels. On-line dosage/monitoring control of a biocide product can be achieved by the addition of an inert fluorescent tracer molecule to a biocide formulation. The benefits of these traced biocides include precise documentation and on-line control of product feed and discharge, measurement of system consumption, and measurement of biocide concentration gradients throughout a system. The attributes of these new approaches to biocide effectiveness monitoring allow for more efficient and economical microbiological treatment of industrial water systems.

  20. Synthesis, characterization and biocidal activities of Schiff base polychelates containing polyurethane links in the main chain

    NASA Astrophysics Data System (ADS)

    Hasnain, Sumaiya; Nishat, Nahid

    The concept of combining metallo-polymers with urethanes offers a versatile approach for the synthesis of new polymeric materials. Polyurethane containing transition metals was synthesized by the reaction of Schiff base metal complex with toluene 2,4 diisocyanate. The proposed structures were confirmed by elemental analysis, 1H NMR, 13C NMR and FT-IR. The geometry is determined by UV-Visible spectra and magnetic moment measurements, which reveals that the Mn(II), Co(II) and Ni(II) complexes have octahedral geometry while square planer geometry is reported for Cu(II) and tetrahedral for Zn(II) complex. The antimicrobial activities are determined using the agar well diffusion method with Staphylococcus aureus, Escherichia coli, Bacillus subtilis (bacteria), Aspergillus niger, Candida albicans and Aspergillus flavus (yeast). All the polymeric metal complexes show comparatively good biocidal activity, which is further enhanced after polymerization.

  1. Research and development of an electrochemical biocide reactor

    NASA Technical Reports Server (NTRS)

    See, G. G.; Bodo, C. A.; Glennon, J. P.

    1975-01-01

    An alternate disinfecting process to chemical agents, heat, or radiation in an aqueous media has been studied. The process is called an electrochemical biocide and employs cyclic, low-level voltages at chemically inert electrodes to pass alternating current through water and, in the process, to destroy microorganisms. The paper describes experimental hardware, methodology, and results with a tracer microorganism (Escherichia coli). The results presented show the effects on microorganism kill of operating parameters, including current density (15 to 55 mA/sq cm (14 to 51 ASF)), waveform of applied electrical signal (square, triangular, sine), frequency of applied electrical signal (0.5 to 1.5 Hz), process water flow rate (100 to 600 cc/min (1.6 to 9.5 gph)), and reactor resident time (0 to 4 min). Comparisons are made between the disinfecting property of the electrochemical biocide and chlorine, bromine, and iodine.

  2. Biocidal properties of metal oxide nanoparticles and their halogen adducts

    NASA Astrophysics Data System (ADS)

    Haggstrom, Johanna A.; Klabunde, Kenneth J.; Marchin, George L.

    2010-03-01

    Nanosized metal oxide halogen adducts possess high surface reactivities due to their unique surface morphologies. These adducts have been used as reactive materials against vegetative cells, such as Escherichia coli as well as bacterial endospores, including Bacillus subtilis and Bacillus anthracis (Δ Sterne strain). Here we report high biocidal activities against gram-positive bacteria, gram-negative bacteria, and endospores. The procedure consists of a membrane method. Transmission electron micrographs are used to compare nanoparticle-treated and untreated cells and spores. It is proposed that the abrasive character of the particles, the oxidative power of the halogens/interhalogens, and the electrostatic attraction between the metal oxides and the biological material are responsible for high biocidal activities. While some activity was demonstrated, bacterial endospores were more resistant to nanoparticle treatment than the vegetative bacteria.

  3. Evaluation of Biofilms and the Effects of Biocides Thereon

    NASA Technical Reports Server (NTRS)

    Pierson, Duane L. (Inventor); Koenig, David W. (Inventor); Mishra, Saroj K. (Inventor)

    2002-01-01

    Biofilm formation is monitored by real-time continuous measurement. Images are formed of sessile cells on a surface and planktonic cells adjacent the surface. The attachment of cells to the surface is measured and quantitated, and sessile and planktonic cells are distinguished using image processing techniques. Single cells as well as colonies are monitored on or adjacent a variety of substrates. Flowing streams may be monitored. The effects of biocides on biofilms commonly isolated from recyclable water systems are measured.

  4. Effects of three oxidizing biocides on Legionella pneumophila serogroup 1

    SciTech Connect

    Domingue, E.L.; Tyndall, R.L.; Mayberry, W.R.; Pancorbo, O.C.

    1988-03-01

    A study was conducted to determine the bactericidal effects of ozone and hydrogen peroxide relative to that of free chlorine on Legionella pneumophila serogroup 1. In laboratory batch-type experiments, organisms seeded at various densities were exposed to different concentrations of these biocides in demand-free buffers. Bactericidal effects were measured by determining the ability of L. pneumophila to grow on buffered charcoal-yeast extract agar supplemented with ..cap alpha..-ketoglutarate. Ozone was the most potent of the three biocide, with a greater than 99% kill of L. pneumophila occurring during a 5-min exposure to 0.10 to 0.30 ..mu..g of O/sub 3/ per ml. The bactericidal action of O/sub 3/ was not markedly affected by changes in pH or temperature. Concentrations of 0.30 and 0.40 /sup +/g of free chlorine per ml killed 99% of the L. pneumophila after 30- and 5-min exposures, respectively. A 30-min exposure to 1000 ..mu..g of H/sub 2/O/sub 2/ per ml was required to effect a 99% reduction of the viable L. pneumophila population. However, no viable L. pneumophila could be detected after a 24-h exposure to 100 or 300 ..mu..g of H/sub 2/O/sub 2/ per ml. Attempts were made to correlate the biocidal effects of O/sub 3/ and H/sub 2/O/sub 2/ with the oxidation of L. pneumophila fatty acids. These tests indicated that certain biocidal concentrations of O/sub 3/ and H/sub 2/O/sub 2/ resulted in a loss or severe reduction of L. pneumophila unsaturated fatty acids.

  5. Inactivation of Lactobacillus delbrueckii bacteriophages by heat and biocides.

    PubMed

    Quiberoni, Andrea; Guglielmotti, Daniela M; Reinheimer, Jorge A

    2003-07-15

    The effect of several biocides and thermal treatments on the viability of four Lactobacillus delbrueckii phages was investigated. Time to achieve 99% inactivation of phages at 63 and 72 degrees C in three suspension media (Tris Magnesium Gelatin (TMG) buffer, Man Rogosa Sharpe (MRS) broth and reconstituted nonfat dry skim milk (RSM)) was calculated. Thermal resistance depended on the phage considered, but a marked heat-resistance was exhibited by one phage (Ib(3)) since its high titre suspensions were completely inactivated only after 45 min at 72 degrees C or 15 min at 90 degrees C. A clear protective effect of the milk was revealed when the three suspension media were compared. As regards to the effects of biocides on phages, only peracetic acid was found to be effective for inactivating high titre suspensions. Ethanol, even at a concentration of 100%, was not suitable to assure no surviving phage particles and isopropanol turned out to be less effective than ethanol. Sodium hypochlorite at 200-400 ppm inactivated the phages completely, except phage Ib(3), which was only destroyed after treatments with 1200 ppm. The diversity observed in the heat and biocide resistance of L. delbrueckii phages is useful to establish a basis for adopting the most effective thermal and chemical treatments for inactivating them in dairy plants and laboratory environments.

  6. Harvesting fresh water and marine algae by magnetic separation: screening of separation parameters and high gradient magnetic filtration.

    PubMed

    Cerff, Martin; Morweiser, Michael; Dillschneider, Robert; Michel, Aymeé; Menzel, Katharina; Posten, Clemens

    2012-08-01

    In this study, the focus is on magnetic separation of fresh water algae Chlamydomonas reinhardtii and Chlorella vulgaris as well as marine algae Phaeodactylum tricornutum and Nannochloropsis salina by means of silica-coated magnetic particles. Due to their small size and low biomass concentrations, harvesting algae by conventional methods is often inefficient and cost-consuming. Magnetic separation is a powerful tool to capture algae by adsorption to submicron-sized magnetic particles. Hereby, separation efficiency depends on parameters such as particle concentration, pH and medium composition. Separation efficiencies of >95% were obtained for all algae while maximum particle loads of 30 and 77 g/g were measured for C. reinhardtii and P. tricornutum at pH 8 and 12, respectively. This study highlights the potential of silica-coated magnetic particles for the removal of fresh water and marine algae by high gradient magnetic filtration and provides critical discussion on future improvements.

  7. Pyrrolamide DNA gyrase inhibitors: fragment-based nuclear magnetic resonance screening to identify antibacterial agents.

    PubMed

    Eakin, Ann E; Green, Oluyinka; Hales, Neil; Walkup, Grant K; Bist, Shanta; Singh, Alok; Mullen, George; Bryant, Joanna; Embrey, Kevin; Gao, Ning; Breeze, Alex; Timms, Dave; Andrews, Beth; Uria-Nickelsen, Maria; Demeritt, Julie; Loch, James T; Hull, Ken; Blodgett, April; Illingworth, Ruth N; Prince, Bryan; Boriack-Sjodin, P Ann; Hauck, Sheila; MacPherson, Lawrence J; Ni, Haihong; Sherer, Brian

    2012-03-01

    DNA gyrase is an essential enzyme in bacteria, and its inhibition results in the disruption of DNA synthesis and, subsequently, cell death. The pyrrolamides are a novel class of antibacterial agents targeting DNA gyrase. These compounds were identified by a fragment-based lead generation (FBLG) approach using nuclear magnetic resonance (NMR) screening to identify low-molecular-weight compounds that bind to the ATP pocket of DNA gyrase. A pyrrole hit with a binding constant of 1 mM formed the basis of the design and synthesis of a focused library of compounds that resulted in the rapid identification of a lead compound that inhibited DNA gyrase with a 50% inhibitory concentration (IC(50)) of 3 μM. The potency of the lead compound was further optimized by utilizing iterative X-ray crystallography to yield DNA gyrase inhibitors that also displayed antibacterial activity. Spontaneous mutants were isolated in Staphylococcus aureus by plating on agar plates containing pyrrolamide 4 at the MIC. The resistant variants displayed 4- to 8-fold-increased MIC values relative to the parent strain. DNA sequencing revealed two independent point mutations in the pyrrolamide binding region of the gyrB genes from these variants, supporting the hypothesis that the mode of action of these compounds was inhibition of DNA gyrase. Efficacy of a representative pyrrolamide was demonstrated against Streptococcus pneumoniae in a mouse lung infection model. These data demonstrate that the pyrrolamides are a novel class of DNA gyrase inhibitors with the potential to deliver future antibacterial agents targeting multiple clinical indications.

  8. Pyrrolamide DNA Gyrase Inhibitors: Fragment-Based Nuclear Magnetic Resonance Screening To Identify Antibacterial Agents

    PubMed Central

    Green, Oluyinka; Hales, Neil; Walkup, Grant K.; Bist, Shanta; Singh, Alok; Mullen, George; Bryant, Joanna; Embrey, Kevin; Gao, Ning; Breeze, Alex; Timms, Dave; Andrews, Beth; Uria-Nickelsen, Maria; Demeritt, Julie; Loch, James T.; Hull, Ken; Blodgett, April; Illingworth, Ruth N.; Prince, Bryan; Boriack-Sjodin, P. Ann; Hauck, Sheila; MacPherson, Lawrence J.; Ni, Haihong; Sherer, Brian

    2012-01-01

    DNA gyrase is an essential enzyme in bacteria, and its inhibition results in the disruption of DNA synthesis and, subsequently, cell death. The pyrrolamides are a novel class of antibacterial agents targeting DNA gyrase. These compounds were identified by a fragment-based lead generation (FBLG) approach using nuclear magnetic resonance (NMR) screening to identify low-molecular-weight compounds that bind to the ATP pocket of DNA gyrase. A pyrrole hit with a binding constant of 1 mM formed the basis of the design and synthesis of a focused library of compounds that resulted in the rapid identification of a lead compound that inhibited DNA gyrase with a 50% inhibitory concentration (IC50) of 3 μM. The potency of the lead compound was further optimized by utilizing iterative X-ray crystallography to yield DNA gyrase inhibitors that also displayed antibacterial activity. Spontaneous mutants were isolated in Staphylococcus aureus by plating on agar plates containing pyrrolamide 4 at the MIC. The resistant variants displayed 4- to 8-fold-increased MIC values relative to the parent strain. DNA sequencing revealed two independent point mutations in the pyrrolamide binding region of the gyrB genes from these variants, supporting the hypothesis that the mode of action of these compounds was inhibition of DNA gyrase. Efficacy of a representative pyrrolamide was demonstrated against Streptococcus pneumoniae in a mouse lung infection model. These data demonstrate that the pyrrolamides are a novel class of DNA gyrase inhibitors with the potential to deliver future antibacterial agents targeting multiple clinical indications. PMID:22183167

  9. Biocide usage in cooling towers in the electric power and petroleum refining industries

    SciTech Connect

    Veil, J.; Rice, J.K.; Raivel, M.E.S.

    1997-11-01

    Cooling towers users frequently apply biocides to the circulating cooling water to control growth of microorganisms, algae, and macroorganisms. Because of the toxic properties of biocides, there is a potential for the regulatory controls on their use and discharge to become increasingly more stringent. This report examines the types of biocides used in cooling towers by companies in the electric power and petroleum refining industries, and the experiences those companies have had in dealing with agencies that regulate cooling tower blowdown discharges. Results from a sample of 67 electric power plants indicate that the use of oxidizing biocides (particularly chlorine) is favored. Quaternary ammonia salts (quats), a type of nonoxidizing biocide, are also used in many power plant cooling towers. The experience of dealing with regulators to obtain approval to discharge biocides differs significantly between the two industries. In the electric power industry, discharges of any new biocide typically must be approved in writing by the regulatory agency. The approval process for refineries is less formal. In most cases, the refinery must notify the regulatory agency that it is planning to use a new biocide, but the refinery does not need to get written approval before using it. The conclusion of the report is that few of the surveyed facilities are having any difficulty in using and discharging the biocides they want to use.

  10. Biocidal Efficacy of Dissolved Ozone, Formaldehyde and Sodium Hypochlorite Against Total Planktonic Microorganisms in Produced Water

    NASA Astrophysics Data System (ADS)

    Puyate, Y. T.; Rim-Rukeh, A.

    The performance of three biocides (dissolved ozone, formaldehyde and sodium hypochlorite) in eliminating the bacteria and fungi in produced water is investigated experimentally. The analysis involves monitoring the microbial population in nine conical flasks each containing the same volume of a mixture of produced water, culture medium that sustains the growth of microorganisms and a known concentration of biocide. The concentrations of each biocide used in the study are 0.1, 0.2 and 0.5 ppm. It is shown that dissolved ozone exhibits the best biocidal characteristics and a concentration of 0.5 ppm eliminated all the microorganisms in the produced water after 150 min contact time.

  11. Screening of enzyme inhibitors from traditional Chinese medicine by magnetic immobilized α-glucosidase coupled with capillary electrophoresis.

    PubMed

    Liu, Dong-Mei; Chen, Juan; Shi, Yan-Ping

    2017-03-01

    As the close correlation between α-glucosidase inhibitors and the treatment of diabetes, in combination with capillary electrophoresis (CE), a method was developed to screen α-glucosidase inhibitors from traditional Chinese medicines (TCMs) by immobilizing α-glucosidase on magnetic nanoparticles. Such a magnetic immobilization would be beneficial for enzyme reusability, stability and separation. In this work, Fe3O4 nanoparticles were synthesized by solvothermal method. And the prepared nanoparticles were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), size and zeta potential analysis. With the modification of chitosan (CS) and glutaraldehyde (GA), α-glucosidase was successfully immobilized on the magnetic nanoparticles. The pH and temperature endurance, storage stability and reusability of the immobilized α-glucosidase were studied and compared with those of the free one. With the magnetic immobilized α-glucosidase, the Michaelis-Menten constant (Km) was calculated to be 0.85mM, and the inhibition constant (Ki) and half-maximal inhibitory concentration (IC50) for acarbose were determined to be 7.37 and 13.69μM, respectively. Finally, the developed method was applied to screen α-glucosidase inhibitors from 18 TCMs.

  12. High-throughput screening by Nuclear Magnetic Resonance (HTS by NMR) for the identification of PPIs antagonists

    PubMed Central

    Wu, Bainan; Barile, Elisa; De, Surya K.; Wei, Jun; Purves, Angela; Pellecchia, Maurizio

    2015-01-01

    In recent years the ever so complex field of drug discovery has embraced novel design strategies based on biophysical fragment screening (fragment-based drug design; FBDD) using nuclear magnetic resonance spectroscopy (NMR) and/or structure-guided approaches, most often using X-ray crystallography and computer modeling. Experience from recent years unveiled that these methods are more effective and less prone to artifacts compared to biochemical high-throughput screening (HTS) of large collection of compounds in designing protein inhibitors. Hence these strategies are increasingly becoming the most utilized in the modern pharmaceutical industry. Nonetheless, there is still an impending need to develop innovative and effective strategies to tackle other more challenging targets such as those involving protein-protein interactions (PPIs). While HTS strategies notoriously fail to identify viable hits against such targets, few successful examples of PPIs antagonists derived by FBDD strategies exist. Recently, we reported on a new strategy that combines some of the basic principles of fragment-based screening with combinatorial chemistry and NMR-based screening. The approach, termed HTS by NMR, combines the advantages of combinatorial chemistry and NMR-based screening to rapidly and unambiguously identify bona fide inhibitors of PPIs. This review will reiterate the critical aspects of the approach with examples of possible applications. PMID:25986689

  13. Subject-friendly entire gastrointestinal screening with a single capsule endoscope by magnetic navigation and the Internet.

    PubMed

    Ohta, Hidetoshi; Katsuki, Shinichi

    2014-01-01

    Ever since capsule endoscopy (CE) was introduced into clinical practice, we gastroenterologists have been dreaming of using this less invasive modality to explore the entire gastrointestinal (GI) tract. To realize this dream, we have developed a magnetic navigation system which includes real-time internet streaming of endoscopic video and some useful gadgets (position detection by means of magnetic impedance (MI) sensors and a modified capsule that is "weightless" in water). The design of the weightless capsule made it possible with 0.5T (Tesla) extracorporeal magnets to control the capsule beyond 20cm. A pair of MI sensors on the body surface could detect subtle magnetic flux generated by an intra-capsular magnet in the GI tract by utilizing the space diversity effect which eliminated the interference of terrestrial magnetism. Subjects underwent CE, during which they were free from confinement in the hospital, except for 1 hour when the capsule was manipulated in the stomach and colon. This study had a completion rate of 97.5%. The high completion rate indicates that our system (single capsule endoscopy-SCE) with further improvements could become a viable modality for screening of the entire GI tract.

  14. A single cell culture system using lectin-conjugated magnetite nanoparticles and magnetic force to screen mutant cyanobacteria.

    PubMed

    Arai, Sayuri; Okochi, Mina; Shimizu, Kazunori; Hanai, Taizo; Honda, Hiroyuki

    2016-01-01

    Cyanobacteria can be utilized as a potential biocatalyst for the production of biofuels and biochemicals directly from CO2. Useful mutants of cyanobacteria, which can grow rapidly or are resistant to specific metabolic products, are essential to improve the productivity of biofuels. In this study, we developed a single cell culture system to effectively screen mutant cyanobacteria using magnetite nanoparticles and magnetic force. Lens culinaris Agglutinin (LCA) was selected as a lectin, which binds to the surface of Synechococcus elongatus PCC7942 cells and the LCA-conjugated magnetite cationic liposomes (MCLs) were developed for magnetic labeling of PCC7942 cells. The MCL-labeled PCC7942 cells were magnetically patterned at a single cell level by using 6,400 iron pillars of the pin-holder device. The device enabled 1,600 single cells to be arrayed in one square centimeter. We cultured the patterned cells in liquid medium and achieved higher colony-forming ratio (78.4%) than that obtained using conventional solid culture method (4.8%). Single cells with different properties could be distinguished in the single cell culture system depending on their growth. Furthermore, we could selectively pick up the target cells and subsequently perform efficient isolation culture. The ratio of successful isolation culture using the developed method was 13 times higher than that of the conventional methods. Thus, the developed system would serve as a powerful tool for screening mutant cyanobacteria.

  15. Identification and Evaluation of Biocides for ROWPU Systems. Revision

    DTIC Science & Technology

    1992-07-01

    other materials are complemented by low toxicity at recommended use levels. 9. Mixture of alycerin and sodium bisulfite : The mixture was run as a control...acceptable candidate for the Filmtec membrane. A mixture of sodium bisulfite and glycerin is used as a storage biocide for the Filmtec membrane...Bromochlorodimethyl Hydantoin, 200 mg/I 7.0 J Cetyltrimethylammonium p-toluene suffonate, 0.1% 7.0 K Sodium Bisulfite , 2.0% 7.0 L Sodium Benzoate/ Sodium Borate

  16. Predicting herbicide and biocide concentrations in rivers across Switzerland

    NASA Astrophysics Data System (ADS)

    Wemyss, Devon; Honti, Mark; Stamm, Christian

    2014-05-01

    Pesticide concentrations vary strongly in space and time. Accordingly, intensive sampling is required to achieve a reliable quantification of pesticide pollution. As this requires substantial resources, loads and concentration ranges in many small and medium streams remain unknown. Here, we propose partially filling the information gap for herbicides and biocides by using a modelling approach that predicts stream concentrations without site-specific calibration simply based on generally available data like land use, discharge and nation-wide consumption data. The simple, conceptual model distinguishes herbicide losses from agricultural fields, private gardens and biocide losses from buildings (facades, roofs). The herbicide model is driven by river discharge and the applied herbicide mass; the biocide model requires precipitation and the footprint area of urban areas containing the biocide. The model approach allows for modelling concentrations across multiple catchments at the daily, or shorter, time scale and for small to medium-sized catchments (1 - 100 km2). Four high resolution sampling campaigns in the Swiss Plateau were used to calibrate the model parameters for six model compounds: atrazine, metolachlor, terbuthylazine, terbutryn, diuron and mecoprop. Five additional sampled catchments across Switzerland were used to directly compare the predicted to the measured concentrations. Analysis of the first results reveals a reasonable simulation of the concentration dynamics for specific rainfall events and across the seasons. Predicted concentration ranges are reasonable even without site-specific calibration. This indicates the transferability of the calibrated model directly to other areas. However, the results also demonstrate systematic biases in that the highest measured peaks were not attained by the model. Probable causes for these deviations are conceptual model limitations and input uncertainty (pesticide use intensity, local precipitation, etc

  17. Enhanced Biocide Mitigation of Field Biofilm Consortia by a Mixture of D-Amino Acids

    PubMed Central

    Li, Yingchao; Jia, Ru; Al-Mahamedh, Hussain H.; Xu, Dake; Gu, Tingyue

    2016-01-01

    Microbiologically influenced corrosion (MIC) is a major problem in the oil and gas industry as well as in many other industries. Current treatment methods rely mostly on pigging and biocide dosing. Biocide resistance is a growing concern. Thus, it is desirable to use biocide enhancers to improve the efficacy of existing biocides. D-Amino acids are naturally occurring. Our previous work demonstrated that some D-amino acids are biocide enhancers. Under a biocide stress of 50 ppm (w/w) hydroxymethyl phosphonium sulfate (THPS) biocide, 1 ppm D-tyrosine and 100 ppm D-methionine used separately successfully mitigated the Desulfovibrio vulgaris biofilm on carbon steel coupons. The data reported in this work revealed that 50 ppm of an equimolar mixture of D-methionine, D-tyrosine, D-leucine, and D-tryptophan greatly enhanced 50 ppm THPS biocide treatment of two recalcitrant biofilm consortia containing sulfate reducing bacteria (SRB), nitrate reducing bacteria (NRB), and fermentative bacteria, etc., from oil-field operations. The data also indicated that individual D-amino acids were inadequate for the biofilm consortia. PMID:27379039

  18. Enhanced Biocide Mitigation of Field Biofilm Consortia by a Mixture of D-Amino Acids.

    PubMed

    Li, Yingchao; Jia, Ru; Al-Mahamedh, Hussain H; Xu, Dake; Gu, Tingyue

    2016-01-01

    Microbiologically influenced corrosion (MIC) is a major problem in the oil and gas industry as well as in many other industries. Current treatment methods rely mostly on pigging and biocide dosing. Biocide resistance is a growing concern. Thus, it is desirable to use biocide enhancers to improve the efficacy of existing biocides. D-Amino acids are naturally occurring. Our previous work demonstrated that some D-amino acids are biocide enhancers. Under a biocide stress of 50 ppm (w/w) hydroxymethyl phosphonium sulfate (THPS) biocide, 1 ppm D-tyrosine and 100 ppm D-methionine used separately successfully mitigated the Desulfovibrio vulgaris biofilm on carbon steel coupons. The data reported in this work revealed that 50 ppm of an equimolar mixture of D-methionine, D-tyrosine, D-leucine, and D-tryptophan greatly enhanced 50 ppm THPS biocide treatment of two recalcitrant biofilm consortia containing sulfate reducing bacteria (SRB), nitrate reducing bacteria (NRB), and fermentative bacteria, etc., from oil-field operations. The data also indicated that individual D-amino acids were inadequate for the biofilm consortia.

  19. Hazard identification of commercially available biocides to control zebra mussels and Asiatic clams. Final report

    SciTech Connect

    Diamond, G.L.; Doherty, F.G.; Michalenko, E.M.; Odin, M.

    1993-10-01

    This report summarizes data on the environmental fate, aquatic toxicology and mammalian toxicology of selected biocides used to control zebra mussels (Dreissena polymorpha). Toxic levels of each biocide or active ingredient are compared to benchmark effluent concentrations (estimates of possible biocide concentrations at the end of cooling water discharge pipes based on doses or residual concentrations at point of fouling recommended by the manufacturer). Comparison of the available data on toxicity to non-target aquatic species shows that the commercial products promoted as molluscicides for control of macrobiological fouling of freshwater cooling systems are relatively non-specific biocides. Toxic effect levels for the most sensitive non-target species for all the biocides exceeded their respective benchmark effluent levels. Data on the mammalian toxicity of the biocides are limited in scope and of poor quality; critical effects were not identified and data were inadequate to assess carcinogenicity or developmental or reproductive toxicity for most of the biocides (ACTI-BROM 1338 and Bulab 6002 appear to be developmental and reproductive toxicants in mammals). Given these limitations in the data, considerable uncertainty is attached to the toxic effect levels selected for comparisons to benchmark effluent levels. Acute toxic effect levels for mammals exceeded benchmark effluent levels for all biocides by factors of 100--1000. Chronic toxic effect levels were closer to benchmark levels, and exceeded benchmarks by less than a factor of 10 for some of the active ingredients of Bulab 6009 and Clam-Trol CT-1.

  20. SOLUBILITY OF ORGANIC BIOCIDES IN SUPERCRITICAL CO2 AND CO2+ COSOLVENT MIXTURES

    EPA Science Inventory

    Solubilities of four organic biocides in supercritical carbon dioxide (Sc-CO2) were measured using a dynamic flowr apparatus over a pressure range of 10 to 30 MPa and temperature of 35-80 degrees C. The biocides studied were: Amical-48 (diiodomethyl p-tolyl sulfone), chlorothalo...

  1. Antimicrobial biocides in the healthcare environment: efficacy, usage, policies, and perceived problems

    PubMed Central

    Maillard, Jean-Yves

    2005-01-01

    Biocides are heavily used in the healthcare environment, mainly for the disinfection of surfaces, water, equipment, and antisepsis, but also for the sterilization of medical devices and preservation of pharmaceutical and medicinal products. The number of biocidal products for such usage continuously increases along with the number of applications, although some are prone to controversies. There are hundreds of products containing low concentrations of biocides, including various fabrics such as linen, curtains, mattresses, and mops that claim to help control infection, although evidence has not been evaluated in practice. Concurrently, the incidence of hospital-associated infections (HAIs) caused notably by bacterial pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) remains high. The intensive use of biocides is the subject of current debate. Some professionals would like to see an increase in their use throughout hospitals, whereas others call for a restriction in their usage to where the risk of pathogen transmission to patients is high. In addition, the possible linkage between biocide and antibiotic resistance in bacteria and the role of biocides in the emergence of such resistance has provided more controversies in their extensive and indiscriminate usage. When used appropriately, biocidal products have a very important role to play in the control of HAIs. This paper discusses the benefits and problems associated with the use of biocides in the healthcare environment and provides a constructive view on their overall usefulness in the hospital setting. PMID:18360573

  2. A green triple biocide cocktail consisting of a biocide, EDDS and methanol for the mitigation of planktonic and sessile sulfate-reducing bacteria.

    PubMed

    Wen, J; Xu, D; Gu, T; Raad, I

    2012-02-01

    Sulfate-reducing bacteria (SRB) cause souring and their biofilms are often the culprit in Microbiologically Influenced Corrosion (MIC). The two most common green biocides for SRB treatment are tetrakis-hydroxymethylphosphonium sulfate (THPS) and glutaraldehyde. It is unlikely that there will be another equally effective green biocide in the market any time soon. This means more effective biocide treatment probably will rely on biocide cocktails. In this work a triple biocide cocktail consisting of glutaraldehyde or THPS, ethylenediaminedisuccinate (EDDS) and methanol was used to treat planktonic SRB and to remove established SRB biofilms. Desulfovibrio vulgaris (ATCC 7757), a corrosive SRB was used as an example in the tests. Laboratory results indicated that with the addition of 10-15% (v/v) methanol to the glutaraldehyde and EDDS double combination, mitigation of planktonic SRB growth in ATCC 1249 medium and a diluted medium turned from inhibition to a kill effect while the chelator dosage was cut from 2,000 to 1,000 ppm. Biofilm removal was achieved when 50 ppm glutaraldehyde combined with 15% methanol and 1,000 ppm EDDS was used. THPS showed similar effects when it was used to replace glutaraldehyde in the triple biocide cocktail to treat planktonic SRB.

  3. Electrochemical biotin detection based on magnetic beads and a new magnetic flow cell for screen printed electrode.

    PubMed

    Biscay, Julien; González García, María Begoña; Costa García, Agustín

    2015-01-01

    The use of the first flow-cell for magnetic assays with an integrated magnet is reported here. The flow injection analysis system (FIA) is used for biotin determination. The reaction scheme is based on a one step competitive assay between free biotin and biotin labeled with horseradish peroxidase (B-HRP). The mixture of magnetic beads modified with streptavidin (Strep-MB), biotin and B-HRP is left 15 min under stirring and then a washing step is performed. After that, 100 μL of the mixture is injected and after 30s 100 μL of 3,3',5,5'-Tetramethylbenzidine (TMB) is injected and the FIAgram is recorded applying a potential of -0.2V. The linear range obtained is from 0.01 to 1 nM of biotin and the sensitivity is 758 nA/nM. The modification and cleaning of the electrode are performed in an easy way due to the internal magnet of the flow cell.

  4. Long-term microfouling on commercial biocidal fouling control coatings.

    PubMed

    Muthukrishnan, Thirumahal; Abed, Raeid M M; Dobretsov, Sergey; Kidd, Barry; Finnie, Alistair A

    2014-01-01

    The current study investigated the microbial community composition of the biofilms that developed on 11 commercial biocidal coatings, including examples of the three main historic types, namely self-polishing copolymer (SPC), self-polishing hybrid (SPH) and controlled depletion polymer (CDP), after immersion in the sea for one year. The total wet weight of the biofilm and the total bacterial density were significantly influenced by all coatings. Pyrosequencing of 16S rRNA genes revealed distinct bacterial community structures on the different types of coatings. Flavobacteria accounted for the dissimilarity between communities developed on the control and SPC (16%) and the control and SPH coatings (17%), while Alphaproteobacteria contributed to 14% of the dissimilarity between the control and CDP coatings. The lowest number of operational taxonomic units was found on Intersmooth 100, while the lowest biomass and density of bacteria was detected on other SPC coatings. The experiments demonstrated that the nature and quantity of biofilm present differed from coating to coating with clear differences between copper-free and copper-based biocidal coatings.

  5. Infectious Disease: Connecting Innate Immunity to Biocidal Polymers.

    PubMed

    Gabriel, Gregory J; Som, Abhigyan; Madkour, Ahmad E; Eren, Tarik; Tew, Gregory N

    2007-08-01

    Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease.

  6. Encystation in Acanthamoeba castellanii: development of biocide resistance.

    PubMed

    Lloyd, D; Turner, N A; Khunkitti, W; Hann, A C; Furr, J R; Russell, A D

    2001-01-01

    Since the early 1960s, axenic culture and the development of procedures for the induction of encystation have made Acanthamoeba spp. superb experimental systems for studies of cell biology and differentiation. More recently, since their roles as human pathogens causing keratitis and encephalitis have become widely recognized, it has become urgent to understand the parameters that determine differentiation, as cysts are much more resistant to biocides than are the trophozoites. Viability of trophozoites of the soil amoeba Acanthamoeba castellanii (Neff), is conveniently measured by its ability to form plaques on a lawn of Escherichia coli. Use of confocal laser scanning microscopy with Calcofluor white, Congo Red or the anionic oxonol dye, DiBAC4(3) or flow cytometry with propidium iodide diacetate and fluorescein or oxonol provides more rapid assessment. For cysts, the plaque method is still the best, because dye exclusion does not necessarily indicate viability and therefore the plate count method has been used to study the sequence of development of biocide resistance during the differentiation process. After two hours, resistance to HCl was apparent. Polyhexamethylene biguanide, benzalkonium chloride, propamidine isethionate, pentamidine isethionate, dibromopropamine isethionate, and H2O2 and moist heat, all lost effectiveness at between 14 and 24 h after trophozoites were inoculated into encystation media. Chlorhexidine diacetate resistance was observed at between 24 and 36 h. The molecular biology and biochemistry of the modifications that underlie these changes are now being investigated.

  7. Infectious Disease: Connecting Innate Immunity to Biocidal Polymers

    PubMed Central

    Gabriel, Gregory J.; Som, Abhigyan; Madkour, Ahmad E.; Eren, Tarik; Tew, Gregory N.

    2007-01-01

    Infectious disease is a critically important global healthcare issue. In the U.S. alone there are 2 million new cases of hospital-acquired infections annually leading to 90,000 deaths and 5 billion dollars of added healthcare costs. Couple these numbers with the appearance of new antibiotic resistant bacterial strains and the increasing occurrences of community-type outbreaks, and clearly this is an important problem. Our review attempts to bridge the research areas of natural host defense peptides (HDPs), a component of the innate immune system, and biocidal cationic polymers. Recently discovered peptidomimetics and other synthetic mimics of HDPs, that can be short oligomers as well as polymeric macromolecules, provide a unique link between these two areas. An emerging class of these mimics are the facially amphiphilic polymers that aim to emulate the physicochemical properties of HDPs but take advantage of the synthetic ease of polymers. These mimics have been designed with antimicrobial activity and, importantly, selectivity that rivals natural HDPs. In addition to providing some perspective on HDPs, selective mimics, and biocidal polymers, focus is given to the arsenal of biophysical techniques available to study their mode of action and interactions with phospholipid membranes. The issue of lipid type is highlighted and the important role of negative curvature lipids is illustrated. Finally, materials applications (for instance, in the development of permanently antibacterial surfaces) are discussed as this is an important part of controlling the spread of infectious disease. PMID:18160969

  8. Magnet-associated intestinal perforation results in a new institutional policy of ferromagnetic screening prior to MRI.

    PubMed

    Baines, Hayley; Saenz, Nicholas C; Dory, Christopher; Marchese, Sara M; Bernard-Stover, Laurie

    2012-12-01

    Foreign body ingestions are common and the vast majority pass through the gastrointestinal tract without complication. Some ingestions, however, result in serious morbidity and mortality. We present a case in which the patient's chief complaint of severe posterior neck pain was unrelated to his foreign body ingestion (multiple magnets). The ingestion of magnets was not disclosed by the child to either the providing medical team or to the patient's family. In order to evaluate the patient's complaint of severe focal neck pain, MRI of the neck was performed. The authors believe it to be feasible that the MRI scan resulted in intestinal perforations that might not have occurred during the natural course of the ingestion. This complication might have been prevented if the patient had undergone screening with a ferromagnetic detector prior to entering the MRI suite. Because of the serious complications related to this case, all pediatric patients at our institution are now screened with ferromagnetic detectors prior to entering the MRI suite. We encourage nationwide policy revision to prevent further incidents similar to the one described in this case.

  9. Optimisation of biocide dose as a function of residual biocide in a heat exchanger pilot plant effluent.

    PubMed

    Eguía, Emilio; Trueba, Alfredo; Girón, Alfredo; Río-Calonge, Belén; Otero, Félix; Bielva, Carlos

    2007-01-01

    Biofouling is one of the most serious problems facing numerous industrial processes. In the case of a heat exchanger unit, biological deposits adhering to the inside surface of its tubes reduce heat transfer and, thus, the thermal performance of the cycle. Control of this phenomenon is proving fundamental for both land and marine equipment to operate in optimum working conditions. Hence, it is necessary to apply antifouling methods capable of keeping surfaces free of any kind of biofouling. This paper reports on the behaviour resulting from use of the flow inversion method vs that obtained by using various chemical treatments. The study compares the effectiveness of certain chemical treatments (Na hypochlorite, peracetic acid and a compound formed by Na bromide + Na hypochlorite) for removing a biofouling film that has already formed on the inside surfaces of tubes in a heat exchanger pilot plant. The paper also addresses the issue of optimising the concentration of biocide dose as a function of the residual biocide in order minimise the environmental impact caused by effluent from industrial plants. The results indicate that it is possible to eliminate a biofilm formed on the inside surfaces of tubes by the use of intermittent doses of chemical treatments at low concentrations and over long application times. Furthermore, once the stabilisation phase is reached 6 d after starting the treatment, it is possible to maintain the conditions achieved using only 20% of the initial dosage.

  10. Screening Magnetic Resonance Imaging Recommendations and Outcomes in Patients at High Risk for Breast Cancer

    PubMed Central

    Ehsani, Sima; Strigel, Roberta M; Pettke, Erica; Wilke, Lee; Tevaarwerk, Amye J; DeMartini, Wendy; Wisinski, Kari B

    2014-01-01

    Objective The purpose of this study was to determine MRI screening recommendations and the subsequent outcomes in women with increased risk for breast cancer evaluated by oncology subspecialists at an academic center. Patients and Methods Patients evaluated between 1/1/2007– 3/1/2011 under diagnosis codes for family history of breast or ovarian cancer, genetic syndromes, lobular carcinoma in situ or atypical hyperplasia were included. Patients with a history of breast cancer were excluded. Retrospective review of prospectively acquired demographics, lifetime risk of breast cancer and screening recommendations were obtained from the medical record. Retrospective review of the results of prospectively interpreted breast imaging examinations and image-guided biopsies were analyzed. Results 282 women were included. The majority of patients were premenopausal with a median age of 43. Most (69%) were referred due to a family history of breast or ovarian cancers. MRI was recommended for 84% of patients based on a documented lifetime risk > 20%. Most women referred for MRI screening (88%) were compliant with this recommendation. A total of 299 breast MRI examinations were performed in 146 patients. Biopsy was performed for 32 (11%) exams and 10 cancers were detected for a PPV of 31% (based on biopsy performed) and an overall per exam cancer yield of 3.3%. Three cancers were detected in patients who did not undergo screening MRI. The 13 cancers were Stage 0-II; all patients were without evidence of disease with a median follow-up of 22 months. Conclusion In a cohort of women seen by breast subspecialty providers, screening breast MRI was recommended according to guidelines, and used primarily premenopausal women with a family history or genetic predisposition to breast cancer. Adherence to MRI screening recommendations was high and cancer yield from breast MRI was similar to that in clinical trials. PMID:25789917

  11. Magnetic dipolar and quadrupolar transitions in two-electron atoms under exponential-cosine-screened Coulomb potential

    SciTech Connect

    Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.

    2015-03-15

    A detailed investigation of the magnetic dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be{sup 2+}, C{sup 4+}, and O{sup 6+} have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s{sup 2}:{sup 1}S{sup e} → 1sns:{sup 3}S{sup e}{sub 0}, and 1snp:{sup 3}P{sup o}{sub 2} (n = 2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.

  12. Novel method for screening of enteric film coatings properties with magnetic resonance imaging.

    PubMed

    Dorożyński, Przemysław; Jamróz, Witold; Niwiński, Krzysztof; Kurek, Mateusz; Węglarz, Władysław P; Jachowicz, Renata; Kulinowski, Piotr

    2013-11-18

    The aim of the study is to present the concept of novel method for fast screening of enteric coating compositions properties without the need of preparation of tablets batches for fluid bed coating. Proposed method involves evaluation of enteric coated model tablets in specially designed testing cell with application of MRI technique. The results obtained in the testing cell were compared with results of dissolution studies of mini-tablets coated in fluid bed apparatus. The method could be useful in early stage of formulation development for screening of film coating properties that will shorten and simplify the development works.

  13. Biocides in hydraulic fracturing fluids: a critical review of their usage, mobility, degradation, and toxicity.

    PubMed

    Kahrilas, Genevieve A; Blotevogel, Jens; Stewart, Philip S; Borch, Thomas

    2015-01-06

    Biocides are critical components of hydraulic fracturing ("fracking") fluids used for unconventional shale gas development. Bacteria may cause bioclogging and inhibit gas extraction, produce toxic hydrogen sulfide, and induce corrosion leading to downhole equipment failure. The use of biocides such as glutaraldehyde and quaternary ammonium compounds has spurred a public concern and debate among regulators regarding the impact of inadvertent releases into the environment on ecosystem and human health. This work provides a critical review of the potential fate and toxicity of biocides used in hydraulic fracturing operations. We identified the following physicochemical and toxicological aspects as well as knowledge gaps that should be considered when selecting biocides: (1) uncharged species will dominate in the aqueous phase and be subject to degradation and transport whereas charged species will sorb to soils and be less bioavailable; (2) many biocides are short-lived or degradable through abiotic and biotic processes, but some may transform into more toxic or persistent compounds; (3) understanding of biocides' fate under downhole conditions (high pressure, temperature, and salt and organic matter concentrations) is limited; (4) several biocidal alternatives exist, but high cost, high energy demands, and/or formation of disinfection byproducts limits their use. This review may serve as a guide for environmental risk assessment and identification of microbial control strategies to help develop a sustainable path for managing hydraulic fracturing fluids.

  14. Development of antimicrobial resistance in Campylobacter jejuni and Campylobacter coli adapted to biocides.

    PubMed

    Mavri, Ana; Smole Možina, Sonja

    2013-01-01

    The potential for adaptive resistance of Campylobacter jejuni and Campylobacter coli after step-wise exposure to increasing sub-inhibitory concentrations of five biocides as triclosan, benzalkonium chloride, cetylpyridinium chloride, chlorhexidine diacetate and trisodium phosphate, was investigated, to identify the mechanisms underlying resistance. The biocide resistance and cross-resistance to the antimicrobials erythromycin and ciprofloxacin, and to sodium dodecyl sulphate, were examined according to the broth microdilution method. The presence of active efflux was studied on the basis of restored sensitivity in the presence of the efflux pump inhibitors phenylalanine-arginine beta-naphthylamide, 1-(1-naphthylmethyl)-piperazine, cyanide 3-chlorophenylhydrazone, verapamil and reserpine. Changes in the outer membrane protein profiles and morphological changes in adapted strains were studied, as compared with the parent strains. Repeated exposure of C. jejuni and C. coli to biocides resulted in partial increases in tolerance to biocides itself, to other biocides and antimicrobial compounds. The developed resistance was stable for up to 10 passages in biocide-free medium. More than one type of active efflux was identified in adapted strains. These adapted strains showed different alterations to their outer membrane protein profiles, along with morphological changes. The data presented here suggest that different mechanisms are involved in adaptation to biocides and that this adaptation is unique to each strain of Campylobacter and does not result from a single species-specific mechanism.

  15. Method for Reduction of Silver Biocide Plating on Metal Surfaces

    NASA Technical Reports Server (NTRS)

    Steele, John; Nalette, Timothy; Beringer, Durwood

    2013-01-01

    Silver ions in aqueous solutions (0.05 to 1 ppm) are used for microbial control in water systems. The silver ions remain in solution when stored in plastic containers, but the concentration rapidly decreases to non-biocidal levels when stored in metal containers. The silver deposits onto the surface and is reduced to non-biocidal silver metal when it contacts less noble metal surfaces, including stainless steel, titanium, and nickel-based alloys. Five methods of treatment of contact metal surfaces to deter silver deposition and reduction are proposed: (1) High-temperature oxidation of the metal surface; (2) High-concentration silver solution pre-treatment; (3) Silver plating; (4) Teflon coat by vapor deposition (titanium only); and (5) A combination of methods (1) and (2), which proved to be the best method for the nickel-based alloy application. The mechanism associated with surface treatments (1), (2), and (5) is thought to be the development of a less active oxide layer that deters ionic silver deposition. Mechanism (3) is an attempt to develop an equilibrium ionic silver concentration via dissolution of metallic silver. Mechanism (4) provides a non-reactive barrier to deter ionic silver plating. Development testing has shown that ionic silver in aqueous solution was maintained at essentially the same level of addition (0.4 ppm) for up to 15 months with method (5) (a combination of methods (1) and (2)), before the test was discontinued for nickel-based alloys. Method (1) resulted in the maintenance of a biocidal level (approximately 0.05 ppm) for up to 10 months before that test was discontinued for nickel-based alloys. Methods (1) and (2) used separately were able to maintain ionic silver in aqueous solution at essentially the same level of addition (0.4 ppm) for up to 10 months before the test was discontinued for stainless steel alloys. Method (3) was only utilized for titanium alloys, and was successful at maintaining ionic silver in aqueous solution at

  16. Biocide Tolerance and Antibiotic Resistance in Salmonella Isolates from Hen Eggshells.

    PubMed

    Fernández Márquez, Maria Luisa; Burgos, María José Grande; Pulido, Rubén Pérez; Gálvez, Antonio; López, Rosario Lucas

    2017-02-01

    The aim of the present study was to determine biocide tolerance and antibiotic resistance in Salmonella isolates from hen eggshells. A total of 39 isolates from hen eggshells, identified as either Salmonella spp. or Salmonella enterica according to 16S rDNA sequencing, were selected for biocide tolerance. Isolates with minimum inhibitory concentrations (MICs) above the wild-type MICs were considered to be biocide tolerant: benzalkonium chloride (BC, 7.7%), cetrimide (CT, 7.7%), hexadecylpyridinium chloride (HDP, 10.3%), triclosan (TC, 17.9%), hexachlorophene (CF, 30.8%), and P3-oxonia (OX, 25.6%). The resulting 21 biocide-tolerant isolates were further characterized. Most isolates (95.2%) were resistant to ampicillin, but only 9.5% were resistant to cefotaxime as well as to ceftazidime. Resistance to chloramphenicol (61.9%), tetracycline (47.6%), streptomycin (19.0%), nalidixic acid (28.6%), ciprofloxacin (9.5%), netilmicin (14.3%), and trimethoprim-sulfamethoxazole (38.1%) was also detected. Considering only antibiotics, 66.7% of isolates were multiresistant; furthermore, 90.5% were multiresistant considering antibiotics and biocides combined. Efflux pump and biocide tolerance genetic determinants detected included acrB (95.2%), oqxA (14.3%), mdfA (9.5%), qacA/B (4.8%), and qacE (9.5%). Antibiotic resistance genes detected included blaTEM (14.3%), blaCTXM-2 (4.8%), blaPSE (4.8%), floR (19.05%), tet(A) (9.5%), tet(C) (4.8%), dfrA12 (0.05%), and dfrA15 (0.05%). Significant positive correlations were detected between phenotypic tolerance/resistance to biocides, biocides and antibiotics, and also between antibiotics, suggesting that a generalized use of biocides could co-select antibiotic resistance.

  17. Effects of Material Choice on Biocide Loss in Orion Water Storage Tanks

    NASA Technical Reports Server (NTRS)

    Wallace, W. T.; Wallace, S. L.; Gazda, D. B.; Lewis, J. F.

    2016-01-01

    When preparing for long-duration spaceflight missions, maintaining a safe supply of potable water is of the utmost importance. One major aspect of that is ensuring that microbial growth is minimized. Historically, this challenge has been addressed through the use of biocides. When using biocides, the choice of materials for the storage containers is important, because surface reactions can reduce biocide concentrations below their effective range. In the water storage system baselined for the Orion vehicle, the primary wetted materials are stainless steel (316 L) and a titanium alloy (Ti6Al4V). Previous testing with these materials has shown that the biocide selected for use in the system (ionic silver) will plate out rapidly upon initial wetting of the system. One potential approach for maintaining an adequate biocide concentration is to spike the water supply with high levels of biocide in an attempt to passivate the surface. To evaluate this hypothesis, samples of the wetted materials were tested individually and together to determine the relative loss of biocide under representative surface area-to-volume ratios after 24 hours. Additionally, we have analyzed the efficacy of disinfecting a system containing these materials by measuring reductions in bacterial counts in the same test conditions. Preliminary results indicate that the use of titanium, either individually or in combination with stainless steel, can result in over 95% loss of biocide, while less than 5% is lost when using stainless steel. In bacterial testing, viable organisms were recovered from samples exposed to the titanium coupons after 24 hours. By comparison, no organisms were recovered from the test vessels containing only stainless steel. These results indicate that titanium, while possessing some favorable attributes, may pose additional challenges when used in water storage tanks with ionic silver biocide.

  18. Weak cation magnetic separation technology and MALDI-TOF-MS in screening serum protein markers in primary type I osteoporosis.

    PubMed

    Shi, X L; Li, C W; Liang, B C; He, K H; Li, X Y

    2015-11-30

    We investigated weak cation magnetic separation technology and matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) in screening serum protein markers of primary type I osteoporosis. We selected 16 postmenopausal women with osteoporosis and nine postmenopausal women as controls to find a new method for screening biomarkers and establishing a diagnostic model for primary type I osteoporosis. Serum samples were obtained from controls and patients. Serum protein was extracted with the WCX protein chip system; protein fingerprints were examined using MALDI-TOF-MS. The preprocessed and model construction data were handled by the ProteinChip system. The diagnostic models were established using a genetic arithmetic model combined with a support vector machine (SVM). The SVM model with the highest Youden index was selected. Combinations with the highest accuracy in distinguishing different groups of data were selected as potential biomarkers. From the two groups of serum proteins, 123 cumulative MS protein peaks were selected. Significant intensity differences in the protein peaks of 16 postmenopausal women with osteoporosis were screened. The difference in Youden index between the four groups of protein peaks showed that the highest peaks had mass-to-charge ratios of 8909.047, 8690.658, 13745.48, and 15114.52. A diagnosis model was established with these four markers as the candidates, and the model specificity and sensitivity were found to be 100%. Two groups of specimens in the SVM results on the scatterplot were distinguishable. We established a diagnosis model, and provided a new serological method for screening and diagnosis of osteoporosis with high sensitivity and specificity.

  19. Naphthoquinones as broad spectrum biocides for treatment of ship's ballast water: toxicity to phytoplankton and bacteria.

    PubMed

    Wright, D A; Dawson, R; Cutler, S J; Cutler, H G; Orano-Dawson, C E; Graneli, E

    2007-03-01

    Current UN International Maritime Organization legislation mandates the phased introduction of ballast water treatment technologies capable of complying with rigorous standards related to removal of waterborne organisms. Doubts concerning mechanical treatments at very high ballasting rates have renewed interest in chemical treatment for very large vessels. High removal rates for biota require broad spectrum biocides that are safe to transport and handle and pose no corrosion problems for ships' structure. The current study focuses on the naphthoquinone group of compounds and extends a previously reported set of screening bioassays with an investigation of the toxicity of four naphthoquinones to select protists and prokaryotes, representative of typical ballast water organisms. Vegetative dinoflagellate cysts exposed to 2.0 mg/L of the naphthoquinones juglone, plumbagin, menadione and naphthazarin showed varying degrees of chloroplast destruction, with menadione demonstrating the most potency. Laboratory and mesocosm exposures of various phytoplankton genera to menadione showed toxicity at 1.0 mg/L. Juglone demonstrated the most bactericidal activity as judged by a Deltatox assay (Vibrio fischeri) and by acridine orange counts of natural bacterial populations.

  20. Vortex-assisted magnetic dispersive solid-phase microextraction for rapid screening and recognition of dicofol residues in tea products.

    PubMed

    Cheng, Xiaoling; Yan, Hongyuan; Wang, Xiaoling; Sun, Ning; Qiao, Xiaoqiang

    2014-11-01

    A simple and rapid vortex-assisted magnetic dispersive solid-phase microextraction (VAMDSME) method coupled with gas chromatography-electronic capture detection was developed for rapid screening and selective recognition of dicofol in tea products. The magnetic molecularly imprinted microspheres (mag-MIMs) synthesised by aqueous suspension polymerisation using dichlorodiphenyltrichloroethane (DDT) as a dummy template showed high selectivity and affinity to dicofol in aqueous solution and were successfully applied as special adsorbents of VAMDSME for rapid isolation of dicofol from complex tea matrix. Good linearity was obtained in a range of 0.2-160 ng g(-1) and the limit of detection based on a signal to noise ratio of 3 was 0.05 ng g(-1). The recoveries at three spiked levels ranged from 83.6% to 94.5% with the related standard deviations (RSD) ⩽ 5.0%. The VAMDSME-GC protocol, which took advantages of the selective adsorption of molecularly imprinted microspheres and rapid magnetic phase separation, as well as the short equilibrium time by vortex-assisted, could avoid the time-consuming procedures related to other traditional extraction methods.

  1. Toxicity of anti-fouling biocides to Parorchis acanthus (Digenea: Philophthalmidae) cercarial encystment.

    PubMed

    Morley, N J; Leung, K M Y; Morritt, D; Crane, M

    2003-03-17

    The toxicity of the anti-fouling biocides tributyltin (TBTO), copper, and Irgarol 1051 (irgarol) at nominal concentrations ranging from 10 to 10,000 microg l(-1) was investigated against the speed of encystment and successful formation of a protective cyst of the cercariae of Parorchis acanthus. For all biocide exposures, cercariae had a much slower rate of encystment and reduced cyst formation than controls. Exposure of the snail host Nucella lapillus for 7 d caused complete cessation of cercarial shedding in irgarol-exposed snails but had no effect on cercarial encystment from TBTO and copper-exposed snails. The mechanisms of toxicity of the biocides are briefly discussed.

  2. Glass-(nAg, nCu) Biocide Coatings on Ceramic Oxide Substrates

    PubMed Central

    Esteban-Tejeda, Leticia; Malpartida, Francisco; Díaz, Luis Antonio; Torrecillas, Ramón; Rojo, Fernando; Moya, José Serafín

    2012-01-01

    The present work was focused on obtaining biocide coatings constituted by a glassy soda-lime matrix containing silver or copper nanoparticles on ceramic (alumina and zirconia based) substrates. Both glassy coatings showed a high biocide activity against Gram−, Gram+ bacteria and yeast, reducing cell numbers more than three logarithms. Silver nanoparticles had a significantly higher biocide activity than copper nanoparticles, since the lixiviation levels required to reduce cell numbers more than 3 logarithms was of almost 1–2 µg/cm2 in the case of silver nanoparticles, and 10–15 µg/cm2 for the copper nanoparticles. PMID:22427967

  3. Magnetic Particles Coupled to Disposable Screen Printed Transducers for Electrochemical Biosensing

    PubMed Central

    Yáñez-Sedeño, Paloma; Campuzano, Susana; Pingarrón, José M.

    2016-01-01

    Ultrasensitive biosensing is currently a growing demand that has led to the development of numerous strategies for signal amplification. In this context, the unique properties of magnetic particles; both of nano- and micro-size dimensions; have proved to be promising materials to be coupled with disposable electrodes for the design of cost-effective electrochemical affinity biosensing platforms. This review addresses, through discussion of selected examples, the way that nano- and micro-magnetic particles (MNPs and MMPs; respectively) have contributed significantly to the development of electrochemical affinity biosensors, including immuno-, DNA, aptamer and other affinity modes. Different aspects such as type of magnetic particles, assay formats, detection techniques, sensitivity, applicability and other relevant characteristics are discussed. Research opportunities and future development trends in this field are also considered. PMID:27681733

  4. Development of a Magnetic Microbead Affinity Selection Screen (MagMASS) Using Mass Spectrometry for Ligands to the Retinoid X Receptor-α

    NASA Astrophysics Data System (ADS)

    Rush, Michael D.; Walker, Elisabeth M.; Prehna, Gerd; Burton, Tristesse; van Breemen, Richard B.

    2016-12-01

    To overcome limiting factors in mass spectrometry-based screening methods such as automation while still facilitating the screening of complex mixtures such as botanical extracts, magnetic microbead affinity selection screening (MagMASS) was developed. The screening process involves immobilization of a target protein on a magnetic microbead using a variety of possible chemistries, incubation with mixtures of molecules containing possible ligands, a washing step that removes non-bound compounds while a magnetic field retains the beads in the microtiter well, and an organic solvent release step followed by LC-MS analysis. Using retinoid X receptor-α (RXRα) as an example, which is a nuclear receptor and target for anti-inflammation therapy as well as cancer treatment and prevention, a MagMASS assay was developed and compared with an existing screening assay, pulsed ultrafiltration (PUF)-MS. Optimization of MagMASS involved evaluation of multiple protein constructs and several magnetic bead immobilization chemistries. The full-length RXRα construct immobilized with amylose beads provided optimum results. Additional enhancements of MagMASS were the application of 96-well plates to enable automation, use of UHPLC instead of HPLC for faster MS analyses, and application of metabolomics software for faster, automated data analysis. Performance of MagMASS was demonstrated using mixtures of synthetic compounds and known ligands spiked into botanical extracts.

  5. Development of a Magnetic Microbead Affinity Selection Screen (MagMASS) Using Mass Spectrometry for Ligands to the Retinoid X Receptor-α

    NASA Astrophysics Data System (ADS)

    Rush, Michael D.; Walker, Elisabeth M.; Prehna, Gerd; Burton, Tristesse; van Breemen, Richard B.

    2017-03-01

    To overcome limiting factors in mass spectrometry-based screening methods such as automation while still facilitating the screening of complex mixtures such as botanical extracts, magnetic microbead affinity selection screening (MagMASS) was developed. The screening process involves immobilization of a target protein on a magnetic microbead using a variety of possible chemistries, incubation with mixtures of molecules containing possible ligands, a washing step that removes non-bound compounds while a magnetic field retains the beads in the microtiter well, and an organic solvent release step followed by LC-MS analysis. Using retinoid X receptor-α (RXRα) as an example, which is a nuclear receptor and target for anti-inflammation therapy as well as cancer treatment and prevention, a MagMASS assay was developed and compared with an existing screening assay, pulsed ultrafiltration (PUF)-MS. Optimization of MagMASS involved evaluation of multiple protein constructs and several magnetic bead immobilization chemistries. The full-length RXRα construct immobilized with amylose beads provided optimum results. Additional enhancements of MagMASS were the application of 96-well plates to enable automation, use of UHPLC instead of HPLC for faster MS analyses, and application of metabolomics software for faster, automated data analysis. Performance of MagMASS was demonstrated using mixtures of synthetic compounds and known ligands spiked into botanical extracts.

  6. Mineralization of the biocide chloroxylenol by electrochemical advanced oxidation processes.

    PubMed

    Skoumal, Marcel; Arias, Conchita; Cabot, Pere Lluís; Centellas, Francesc; Garrido, José Antonio; Rodríguez, Rosa María; Brillas, Enric

    2008-04-01

    Electrochemical advanced oxidation processes (EAOPs) are environmentally friendly methods based on the destruction of organic pollutants in wastewaters with in situ electrogenerated hydroxyl radical. This species is formed in anodic oxidation (AO) from water oxidation at the anode and in indirect electro-oxidation methods like electro-Fenton (EF) and photoelectro-Fenton (PEF) also from reaction between catalytic Fe2+ and H2O2 continuously produced at the O2-diffusion cathode. The PEF method involves the irradiation of the treated solution with UVA light to enhance the photolysis of organics including Fe(III) complexes. In this work, the oxidation power of such EAOPs to decontaminate synthetic wastewaters of the biocide chloroxylenol (4-chloro-3,5-dimethylphenol) at pH 3.0 is comparatively examined with an undivided electrolytic cell containing a Pt or boron-doped diamond (BDD) anode and a stainless steel or O2-diffusion cathode. The initial chlorine is released as Cl(-) ion, which remains stable in the medium using Pt or is oxidized to Cl2 on BDD. The biocide solutions can be completely decontaminated using AO with a BDD anode, as well as PEF with a Pt or BDD anode. The PEF procedure with a BDD anode is the most powerful method leading to total mineralization in about 300 min, practically independent of current density. When current density rises, the degradation rate of processes increases, but they become less efficient due to the larger enhancement of waste reactions of oxidants. Chloroxylenol is much more rapidly removed in EF and PEF than in AO. 2,6-dimethylhydroquinone, 2,6-dimethyl-p-benzoquinone and 3,5-dimethyl-2-hydroxy-p-benzoquinone are identified as aromatic by-products, and maleic, malonic, pyruvic, acetic and oxalic acids are found as generated carboxylic acids. A general pathway for chloroxylenol mineralization by all EAOPs including the above by-products is proposed.

  7. Screening inhibitors of xanthine oxidase from natural products using enzyme immobilized magnetic beads by high-performance liquid chromatography coupled with tandem mass spectrometry.

    PubMed

    Wang, Ting; Li, Dapeng; Yu, Boyang; Qi, Jin

    2017-03-06

    In this study, high-performance liquid chromatography coupled with tandem mass spectrometry was used to assess the results of bioactive compound screening from natural products using immobilized enzyme magnetic beads. We compared three commercial magnetic beads with modified amino, carboxy and N-hydroxysuccinimide groups, respectively. Amino magnetic beads performed best for immobilization and were selected for further experiments. Xanthine oxidase was immobilized on amino magnetic beads and applied to screen potential inhibitors in fresh Zingiber officinale Roscoe, extracts of Scutellaria baicalensis Georgi and Pueraria lobata Ohwi. In total, 12 potential xanthine oxidase ligands were identified from fresh Zingiber root and Scutellaria root extracts, of which eight were characterized and the concentration required for 50% inhibition was determined. Preliminary structure-function relationships were discussed based on these results. A convenient and effective method was therefore developed for the identification of active compounds from complex natural product mixtures. This article is protected by copyright. All rights reserved.

  8. Alkyl ammonium cation stabilized biocidal polyiodides with adaptable high density and low pressure.

    PubMed

    He, Chunlin; Parrish, Damon A; Shreeve, Jean'ne M

    2014-05-26

    The effective application of biocidal species requires building the active moiety into a molecular back bone that can be delivered and decomposed on demand under conditions of low pressure and prolonged high-temperature detonation. The goal is to destroy storage facilities and their contents while utilizing the biocidal products arising from the released energy to destroy any remaining harmful airborne agents. Decomposition of carefully selected iodine-rich compounds can produce large amounts of the very active biocides, hydroiodic acid (HI) and iodine (I2). Polyiodide anions, namely, I3(-), I5(-), which are excellent sources of such biocides, can be stabilized through interactions with large, symmetric cations, such as alkyl ammonium salts. We have designed and synthesized suitable compounds of adaptable high density up to 3.33 g cm(-3) that are low-pressure polyiodides with various alkyl ammonium cations, deliverable iodine contents of which range between 58.0-90.9%.

  9. A macroalgal germling bioassay to assess biocide concentrations in marine waters.

    PubMed

    Girling, J A; Thomas, K V; Brooks, S J; Smith, D J; Shahsavari, E; Ball, A S

    2015-02-15

    A bioassay method using the early life stages (germlings) of macroalgae was developed to detect toxicity of anti-fouling paint biocides. A laboratory based bioassay using Ulva intestinalis and Fucus spiralis germlings was performed with 4 common anti-fouling biocides (tributyltin (TBT), Irgarol 1051, Diuron and zinc sulphate), over a range of environmentally relevant concentrations (0.0033-10 μg l(-1)). Comparison between the two species showed that germlings of U. intestinalis were better adapted for in-situ monitoring, as germlings of F. spiralis appeared to be too robust to display sufficient growth differences. The response of U. intestinalis germling growth appeared to reflect environmental biocide concentrations. Overall the developed method showed potential for the assessment of the sub-lethal effects of anti-fouling biocides on the early developmental stages of U. intestinalis.

  10. Screened QED corrections in lithiumlike heavy ions in the presence of magnetic fields.

    PubMed

    Volotka, A V; Glazov, D A; Shabaev, V M; Tupitsyn, I I; Plunien, G

    2009-07-17

    A rigorous evaluation of the complete gauge-invariant set of the screened one-loop QED corrections to the hyperfine structure and g factor in lithiumlike heavy ions is presented. The calculations are performed in both Feynman and Coulomb gauges for the virtual photon mediating the interelectronic interaction. As a result, the most accurate theoretical predictions for the specific difference between the hyperfine splitting values of H- and Li-like Bi ions as well as for the g factor of the Li-like Pb ion are obtained.

  11. Fabrication of enzyme reactor utilizing magnetic porous polymer membrane for screening D-Amino acid oxidase inhibitors.

    PubMed

    Jiang, Jun Fang; Qiao, Juan; Mu, Xiao Yu; Moon, Myeong Hee; Qi, Li

    2017-04-01

    In this work, a unique D-amino acid oxidase reactor for enhanced enzymolysis efficiency is presented. A kind of magnetic polymer matrices, composed of iron oxide nanoparticles and porous polymer membrane (poly styrene-co-maleic anhydride), was prepared. With covalent bonding D-Amino acid oxidase on the surface of the matrices and characterization of scanning electron microscope and vibrating sample magnetometer, it demonstrated that the membrane enzyme reactor was successfully constructed. The enzymolysis efficiency of the enzyme reactor was evaluated and the apparent Michaelis-Menten constants of D-Amino acid oxidase were determined (Km was 1.10mM, Vmax was 23.8mMmin(-1)) by a chiral ligand exchange capillary electrophoresis protocol with methionine as the substrate. The results indicated that the enzyme reactor could exhibit good stability and excellent reusability. Importantly, because the enzyme and the substrate could be confined into the pores of the matrices, the enzyme reactor displayed the improved enzymolysis efficiency due to the confinement effect. Further, the prepared enzyme reactor was applied for D-Amino acid oxidase inhibitors screening. It has displayed that the proposed protocol could pave a new way for fabrication of novel porous polymer membrane based enzyme reactors to screen enzyme inhibitors.

  12. Screening nucleotide binding to amino acid-coated supports by surface plasmon resonance and nuclear magnetic resonance.

    PubMed

    Cruz, Carla; Cabrita, Eurico J; Queiroz, João A

    2011-08-01

    Here, we describe a rapid and efficient screening method using surface plasmon resonance (SPR) and saturation transfer difference-nuclear magnetic resonance (STD-NMR) spectroscopy to yield information regarding the residues involved in nucleotide binding to amino acid-coated supports. The aim of this work was to explore the use of these spectroscopic techniques to study amino acid-nucleotide interactions in order to improve the binding specificity of the amino acid ligands used to purify plasmid DNA. For SPR, we present a strategy that immobilizes arginine and lysine on a surface as model supports, and we analyze binding responses when synthetic homo-deoxyoligonucleotides are injected over the amino acid surface. The binding responses are detectable and reproducible despite the small size of the immobilized amino acids. Using STD-NMR, we performed epitope mapping of homo-deoxyoligonucleotides bound to L-arginine-bisoxyran-Sepharose and L-lysine-Sepharose supports. Polynucleotide binding preferences differed; for example, polyC interacted preferentially through its backbone with the two supports, whereas polyT bound the supports through its thymine moiety. STD-NMR combined with SPR measurements was successfully used to screen amino acid-nucleotide interactions and determine the binding affinities of the complexes.

  13. Bioassays and selected chemical analysis of biocide-free antifouling coatings.

    PubMed

    Watermann, B T; Daehne, B; Sievers, S; Dannenberg, R; Overbeke, J C; Klijnstra, J W; Heemken, O

    2005-09-01

    Over the years several types of biocide-free antifouling paints have entered the market. The prohibition of biocidal antifouling paints in special areas of some European countries such as Sweden, Denmark and Germany has favoured the introduction of these paints to the market. Several types of biocide-free antifouling paints were subjected to bioassays and selected chemical analysis of leachate and incorporated substances. Both non-eroding coatings (silicones, fibre coats, epoxies, polyurethane, polyvinyl) and eroding coatings (SPCs, ablative) were tested to exclude the presence of active biocides and dangerous compounds. The paints were subjected to the luminescent bacteria test and the cypris larvae settlement assay, the latter delivering information on toxicity as well as on efficacy. The following chemical analyses of selected compounds of dry-film were performed: The results of the bioassays indicated that none of the coatings analysed contained leachable biocides. Nevertheless, some products contained or leached dangerous compounds. The analyses revealed leaching of nonylphenol (up to 74.7 ng/cm2/d after 48 h) and bisphenol A (up to 2.77 ng/cm2/d after 24 h) from epoxy resins used as substitutes for antifouling paints. The heavy metal, zinc, was measured in dry paint film in quantities up to 576,000 ppm in erodable coatings, not incorporated as a biocide but to control the rate of erosion. Values for TBT in silicone elutriates were mostly below the detection limit of 0.005 mg/kg. Values for DBT ranged between <0.005 and 6.28 mg/kg, deriving from catalysts used as curing agents. Some biocide-free paints contained leachable, toxic and dangerous compounds in the dry film, some of which may act as substitutes for biocides or are incorporated as plasticizers or catalysts. Implications to environmental requirements and legislation are discussed.

  14. Ignition and Combustion Characteristics of Nanoscale Al/AgIO3: A Potential Energetic Biocidal System

    DTIC Science & Technology

    2011-01-01

    reaction of Al/AgIO3 thermites for potential use in biocidal applications . Rapid-heating wire experiments were performed to measure the ignition...OF: This work investigates the ignition and reaction of Al/AgIO3 thermites for potential use in biocidal applications . Rapid-heating wire experiments...were performed to measure the ignition temperature and investigate the thermal decomposition of the oxidizer using a T-Jump/TOF Mass Spectrometer

  15. Quaternary ammonium biocides as antimicrobial agents protecting historical wood and brick.

    PubMed

    Rajkowska, Katarzyna; Koziróg, Anna; Otlewska, Anna; Piotrowska, Małgorzata; Nowicka-Krawczyk, Paulina; Brycki, Bogumił; Kunicka-Styczyńska, Alina; Gutarowska, Beata

    2016-01-01

    Quaternary ammonium compounds (QACs) are widely used in disinfection of water, surfaces and instruments as well as in textile, leather and food industries because of their relatively low toxicity, broad antimicrobial spectrum, non-volatility and chemical stability. Due to these advantages, QACs are also used in restoration and can be applied on historical material. The aim of this study was to determine the usefulness of biocides based on quaternary ammonium salts and containing various excipients in the protection of historical materials against microbial growth. The study determined the antimicrobial activity of three biocides against bacteria: Pseudomonas fluorescens, Staphylococcus equorum, Bacillus cereus, Bacillus muralis, Sporosarcina aquimarina and Rhodococcus fascians, and moulds: Chaetomium globosum, Penicillium citreonigrum, Cladosporium cladosporioides I, Acremonium strictum, Aspergillus fumigatus and Cladosporium cladosporioides II, all isolated from historical wood and brick. Staphylococcus equorum, Bacillus cereus, Sporosarcina aquimarina and Rhodococcus fascians bacteria, and Cladosporium cladosporioides I and Acremonium strictum moulds showed high sensitivity to quaternary ammonium biocides. Historical wood can be effectively disinfected by three applications of biocide A (30% v/v) containing dodecyl dimethyl ammonium chloride (DDAC), citric acid, propiconazole and propanol. Disinfection of historical brick can be carried out by three applications of 6% v/v solutions of biocide B (based on DDAC and ethylenediaminetetraacetic acid - EDTA) or biocide C (containing a non-ionic surfactant, DDAC and EDTA). Effective protection of historical building materials against microbial growth for a period of seven days can be achieved by the application of biocide A (30% v/v) on the wood surface and biocide B (6% v/v) on the brick surface.

  16. Development of a rapid ATP bioluminescence assay for biocidal susceptibility testing of rapidly growing mycobacteria.

    PubMed

    Kapoor, Renuka; Yadav, Jagjit S

    2010-10-01

    An ATP-based biocide susceptibility assay for mycobacteria was developed by optimizing the cell lysis and assay conditions. Compared to the conventional agar plating method, the assay was rapid (1.5 h) and showed high sensitivity and specificity as determined by receiver operating characteristic (ROC) analysis. The test species, Mycobacterium immunogenum, M. chelonae, and M. abscessus, showed various susceptibilities to the glutaraldehyde- and isothiazolone-based test biocides.

  17. Predicting dermal permeability of biocides in commercial cutting fluids using a LSER approach.

    PubMed

    Vijay, Vikrant; Yeatts, James L; Riviere, Jim E; Baynes, Ronald E

    2007-12-10

    The aim of this study is to predict dermal permeability of four phenolic biocides in four different formulations using a linear solvation energy relationship (LSER) approach, with a calibrated flow through diffusion cell system. Mathematical descriptors were determined in the laboratory, by mathematical computations, and by statistical methods. Infinite doses of 4 biocides and 25 probe chemicals in water, 17% methanol and 2 commercial metalworking fluids namely Astrocut-C and Tapfree 2 were applied to porcine skin flow through diffusion cells. The strength coefficients for the 25 probe compounds for each system were determined from multiple linear regression analysis and plugged into the Abraham's LSER equation to predict permeability values for biocides. Biocide permeability significantly decreased in methanol, Astrocut-C and Tapfree 2 when compared to water. The strength coefficients revealed that hydrophobicity played an important role in explaining the reduced permeability in vehicles compared to water. This finding is important for selection of biocides and cutting fluids formulation. The R(2) between experimental and predicted log Kp of probe solutes for water, methanol, Astrocut-C and Tapfree 2 were 0.70, 0.78, 0.89 and 0.84, respectively. In conclusion, the LSER approach adequately predicted the dermal permeability of four biocides in commercial cutting fluids and also shed light on the chemical interactions resulting in reduced permeability.

  18. Effects of Biocides and Other Metal Removal Fluid Constituents on Mycobacterium immunogenum▿

    PubMed Central

    Falkinham, Joseph O.

    2009-01-01

    Cells of Mycobacterium immunogenum are significantly more resistant to biocides and antimicrobial compounds used for disinfection of metal removal fluids (MRFs) than cells of the gram-negative bacterium Pseudomonas pseudoalcaligenes. To ensure accurate measurement of M. immunogenum susceptibility, a biocide inactivation step must be included to prevent an overestimation of killing for short-term exposures. Cell suspensions in 5% MRF for 30 min rather than direct plating following biocide exposure increased the killing of M. immunogenum cells, suggesting a heretofore undiscovered interaction between MRF components and biocides. Biocide killing was reduced at high M. immunogenum cell densities (>106/ml). Among the chemicals tested, only Synergex Premier, Preventol CMK, and dicyclohexylamine killed greater than 90% of M. immunogenum cells in 6 h. M. immunogenum cells adhered to and grew rapidly on glass, copper, and galvanized surfaces, forming biofilms of 106 cells/cm2 within 2 weeks and suggesting it is likely that the majority of M. immunogenum cells in MRF systems are on surfaces. M. immunogenum cells grown on surfaces in biofilms were three- to 100-fold more resistant to the biocides Synergex Premier and Preventol CMK than cells grown in suspension, compounding the problem of eradication of M. immunogenum cells from MRF systems. PMID:19201985

  19. Adsorption and release of biocides with mesoporous silica nanoparticles

    NASA Astrophysics Data System (ADS)

    Popat, Amirali; Liu, Jian; Hu, Qiuhong; Kennedy, Michael; Peters, Brenton; Lu, Gao Qing (Max); Qiao, Shi Zhang

    2012-01-01

    In this proof-of-concept study, an agricultural biocide (imidacloprid) was effectively loaded into the mesoporous silica nanoparticles (MSNs) with different pore sizes, morphologies and mesoporous structures for termite control. This resulted in nanoparticles with a large surface area, tunable pore diameter and small particle size, which are ideal carriers for adsorption and controlled release of imidacloprid. The effect of pore size, surface area and mesoporous structure on uptake and release of imidacloprid was systematically studied. It was found that the adsorption amount and release profile of imidacloprid were dependent on the type of mesoporous structure and surface area of particles. Specifically, MCM-48 type mesoporous silica nanoparticles with a three dimensional (3D) open network structure and high surface area displayed the highest adsorption capacity compared to other types of silica nanoparticles. Release of imidacloprid from these nanoparticles was found to be controlled over 48 hours. Finally, in vivo laboratory testing on termite control proved the efficacy of these nanoparticles as delivery carriers for biopesticides. We believe that the present study will contribute to the design of more effective controlled and targeted delivery for other biomolecules.In this proof-of-concept study, an agricultural biocide (imidacloprid) was effectively loaded into the mesoporous silica nanoparticles (MSNs) with different pore sizes, morphologies and mesoporous structures for termite control. This resulted in nanoparticles with a large surface area, tunable pore diameter and small particle size, which are ideal carriers for adsorption and controlled release of imidacloprid. The effect of pore size, surface area and mesoporous structure on uptake and release of imidacloprid was systematically studied. It was found that the adsorption amount and release profile of imidacloprid were dependent on the type of mesoporous structure and surface area of particles

  20. Active moss biomonitoring for extensive screening of urban air pollution: Magnetic and chemical analyses.

    PubMed

    Vuković, Gordana; Urošević, Mira Aničić; Goryainova, Zoya; Pergal, Miodrag; Škrivanj, Sandra; Samson, Roeland; Popović, Aleksandar

    2015-07-15

    In this study, active magnetic biomonitoring of moss for particulate air pollution and an assessment of heavy metals and polycyclic aromatic hydrocarbons (PAHs) were performed for the entire metropolitan area of Belgrade. Two mosses, Sphagnum girgensohnii (a species of the most recommended biomonitoring moss genus) and Hypnum cupressiforme (a common moss in the study area), were used. During the summer of 2013, moss bags were exposed at 153 sampling sites, forming a dense network of sites. A type II regression model was applied to test the interchangeable use of the two moss species. Significantly higher levels of all measured pollutants were recorded by S. girgensohnii in comparison with H. cupressiforme. Based on the results, the mosses could not be interchangeably used in urban areas, except for the biomonitoring of Cu. Nevertheless, according to the relative accumulation factors obtained for both moss species, similar city zones related to high, moderate and low levels of air pollution were distinguished. Moreover, new pollution hotspots, omitted by regulatory monitoring, were identified. The results demonstrate that moss magnetic analysis represents an effective first step for obtaining an overview of particulate air pollution before more expensive chemical analyses. Active moss biomonitoring could be applied as a pragmatic approach for optimizing the representativeness of regulatory monitoring networks.

  1. Biocides in hydraulic fracturing: hazard and vulnerability with respect to potential groundwater pollution

    NASA Astrophysics Data System (ADS)

    Worrall, Fred; Wilson, Miles; Davies, Richard

    2016-04-01

    Biocides are one possible chemical additive to frack fluids and their role is to control bacterial growth. Bacterial growth might lead to biofilm build up; and acid sulfide species and hydrogen sulfide (H2S) production: biofilm build up may reduce formation permeability and hinder gas extraction. Kahrilas et al. (2014) published a review of common biocides used in fracking in the USA. The biocides assessed in the review were the sixteen most commonly used in the USA, based on the hydraulic fracturing chemical registry Frac Focus (Frac Focus, 2015). However, the review of Kahrilas et al. (2014) contained no data or observations and so the objective of this study was to consider whether biocides proposed for use in hydrofacturing could be a threat to English groundwater. The study considered all groundwater samples analysed for biocides in English groundwater between 2005 and 2014. The monitoring records were compared to: records of application (both amount and area); and chemical and molecular data for the biocides. The study did not use traditional adsorption and degradation data as these parameters are to prone to variability and are not pure molecular parameters. The study then used the approach of Worrall and Thomsen (2004) to consider the hazard represented by proposed frack biocides and the approach of Worrall and Kolpin (2003) to consider the vulnerability of the areas of potential shale gas exploitation. The study showed that of the 113 biocides tested for in English groundwaters in the decade 2005 - 2014 that 95 were detected above 0.1 g/l . Of these 95, 41 were compounds that were not recorded as being applied during the period of record and the detection of these 41 compounds did not decline over the 10 year period which implies very long residence times and that once compounds do pollute an aquifer then they will be a persistent problem. Furthermore, the solubility of the range of biocides used in frack fluids would imply a potentially higher hazard

  2. The carcinogenicity of the biocide ortho-phenylphenol.

    PubMed

    Appel, K E

    2000-04-01

    The biocides ortho-phenylphenol and its sodium salt (OPP and SOPP) are widely used as fungicides and antibacterial agents for commercial and consumer purposes. The carcinogenicity of OPP/SOPP toward the urinary bladder was demonstrated when rats were chronically fed concentrations of 0.5%-4% in their diet. Other species tested so far did not develop tumours. Understanding the mechanisms underlying OPP/SOPP-induced bladder carcinogenesis is critical to determine whether risks observed at high doses in rats are of relevance to humans exposed at much lower levels. This overview details experimental studies of carcinogenicity, genotoxicity as well as metabolism/toxicokinetics and other mechanistic studies which bear on cancer hazard and risk evaluation of exposure to humans. Based on the presently available knowledge, it is concluded that reactive quinoid metabolites exhibiting redox cycling activities are the crucial factors. At certain concentration levels, these metabolites are able to produce cytotoxic events with concomitant enhanced cell proliferation of the target tissue. Further important risk factors are probably promutagenic lesions induced by oxidative stress and a higher urinary pH. Supposed that these mechanisms are the basis for the tumourigenicity observed, then suitable low doses of OPP/SOPP will practically pose no cancer risk.

  3. One-pot facile green synthesis of biocidal silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Nudrat Hazarika, Shabiha; Gupta, Kuldeep; Shamin, Khan Naseem Ahmed Mohammed; Bhardwaj, Pushpender; Boruah, Ratan; Yadav, Kamlesh K.; Naglot, Ashok; Deb, P.; Mandal, M.; Doley, Robin; Veer, Vijay; Baruah, Indra; Namsa, Nima D.

    2016-07-01

    The plant root extract mediated green synthesis method produces monodispersed spherical shape silver nanoparticles (AgNPs) with a size range of 15-30 nm as analyzed by atomic force and transmission electron microscopy. The material showed potent antibacterial and antifungal properties. Synthesized AgNPs display a characteristic surface plasmon resonance peak at 420 nm in UV-Vis spectroscopy. X-ray diffractometer analysis revealed the crystalline and face-centered cubic geometry of in situ prepared AgNPs. Agar well diffusion and a colony forming unit assay demonstrated the potent biocidal activity of AgNPs against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae, Pseudomonas diminuta and Mycobacterium smegmatis. Intriguingly, the phytosynthesized AgNPs exhibited activity against pathogenic fungi, namely Trichophyton rubrum, Aspergillus versicolor and Candida albicans. Scanning electron microscopy observations indicated morphological changes in the bacterial cells incubated with silver nanoparticles. The genomic DNA isolated from the bacteria was incubated with an increasing concentration of AgNPs and the replication fidelity of 16S rDNA was observed by performing 18 and 35 cycles PCR. The replication efficiency of small (600 bp) and large (1500 bp) DNA fragments in the presence of AgNPs were compromised in a dose-dependent manner. The results suggest that the Thalictrum foliolosum root extract mediated synthesis of AgNPs could be used as a promising antimicrobial agent against clinical pathogens.

  4. Biocide silver nanoparticles in two different silica-based coating

    NASA Astrophysics Data System (ADS)

    Babapour, A.; Yang, B.; Bahang, S.; Cao, W.

    2012-09-01

    Silica-based coatings containing biocide silver nanoparticles have been synthesized using low temperature sol-gel method. Two different silane based matrices, phenyltriethoxysilane (PhTEOS) and tetraethyl orthosilicate (TEOS), were selected as precursor to prepare silica-based film. The films were analyzed by using UV-visible spectrophotometry, atomic force microscopy (AFM) and scanning electron microscopy (SEM) for their optical, surface morphological as well as structural properties. Optical properties of nanosilver in these two matrices showed that the peak absorption observed at different wavelength, which is due to the fact that optical absorption of nanoparticles is affected by the surrounding medium. It is also found that the silver absorption has higher intensity in PhTEOS than in TEOS matrix, indicating higher concentration of silver nanoparticles being loaded into the coating. To study silver release property, the films were immersed in water for 12 and 20 days. AFM and SEM analyzes present that higher concentration of silver nanoparticles and smaller particle sizes were synthesis in PhTEOS coating and consequently, more particles remains on the surfaces after 20 days which leads to longer antibacterial activity of PhTEOS coating.

  5. Ceramic/metal biocidal nanocomposites for bone-related applications.

    PubMed

    Miranda, Miriam; Fernández, Adolfo; Lopez-Esteban, Sonia; Malpartida, Francisco; Moya, José S; Torrecillas, Ramón

    2012-07-01

    Hydroxyapatite/silver nanocomposites have been designed and synthesized as an engineering material for biomedical applications. The hydroxyapatite matrix was synthesized by a sol-gel method and, subsequently, the Ag nanoparticles were deposited by heterogeneous precipitation followed by two different reduction routes: thermal or chemical. Both sets were studied and compared and, in all cases, the metal nanoparticles appear perfectly isolated and attached to the surface of the hydroxyapatite. The average metal particle size is below 10 nm, allowing an important contact surface between silver and the microorganisms. The antimicrobial behavior against common bacteria showed a high effectiveness, well above the commercial level, as well as against yeast, in the case of the chemically reduced sample. Due to the nanocomposite microstructure, only a negligible portion of metal was released to the lixiviated liquid after the biocide tests, minimizing the risk of toxicity. These nanocomposites offer a solution to the infections on the surface of implants, one of the main problems in reaching a suitable level of osseointegration.

  6. Biocide tolerance in Salmonella from meats in Southern Spain

    PubMed Central

    Garrido, Antonio Marin; Burgos, Mª Jose Grande; Márquez, Mª Luisa Fernández; Aguayo, Mª Carmen López; Pulido, Rubén Pérez; del Árbol, Julia Toledo; Gálvez, Antonio; López, Rosario Lucas

    2015-01-01

    Salmonella serovars sampled from meat products in Southern Spain (Andalucía) during the period 2002-2007 were analyzed in this study. The serovars most frequently detected (in order) were Typhimurium, Enteritidis, Derby, Anatum and Rissen. Isolates (n = 43) were tested for sensitivity to biocides, including the quaternary ammonium compounds benzalkonium chloride (BC), cetrimide (CT) and hexadecylpyridinium chloride (HDP), and the bisphenols triclosan (TC) and hexachlorophene (CF). The minimum inhibitory concentration (MIC) for the quaternary ammonium compounds was in the range of 25 to 50 mg/L for most isolates, although a few isolates required much higher concentrations, up to 250 mg/L. Bisphenols showed higher inhibitory activity, with a MIC of 2.5 to 25 mg/L. A few isolates showed a “non-wildtype” MIC for TC of up to 250 mg/L. These results indicate a low incidence of tolerance towards quaternary ammonium compounds and triclosan among Salmonella from meats and meat products. PMID:26691479

  7. Lemon juice as a natural biocide for disinfecting drinking water.

    PubMed

    D'Aquino, M; Teves, S A

    1994-12-01

    The natural biocidal activity of lemon juice was studied in order to explore its possible use as a disinfectant and inhibitor of Vibrio cholerae in drinking water for areas lacking water treatment plants. From January through July 1993, water samples of varying alkalinity and hardness were prepared artificially, and underground and surface water samples were obtained from a number of different rural and urban areas in Argentina's Buenos Aires Province. After measuring the latter samples' hardness and alkalinity, a range of concentrations of lemon juice and other acidifiers were added to each sample, and the resulting pH as well as the samples' ability to destroy V. cholerae were determined. The results show that lemon juice can actively prevent survival of V. cholerae but that such activity is reduced in markedly alkaline water. For example, treatment of underground drinking water, which is characterized as having the greatest degree of alkalinity in our area, will typically destroy V. cholerae if the alkalinity of the water is the equivalent of that produced by 200 mg CaCO3 per liter, if enough lemon juice is added to bring the lemon juice concentration to 2%, and if the lemon juice is allowed to act for 30 minutes. All this points up the need to determine the alkalinity of water from any local source to be treated in the process of assessing the minimum concentration of lemon juice required.

  8. New biocide-free anti-fouling paints are toxic.

    PubMed

    Karlsson, Jenny; Eklund, Britta

    2004-09-01

    A number of new anti-fouling paints claimed to be more friendly to the environment, have entered the market since prohibition of biocide containing paints have been enforced in many areas. Leakage waters from five new anti-fouling paints were tested for toxic effects to the macro algae Ceramium tenuicorne and Ceramium strictum and to the crustacean Nitocra spinipes. A banned copper and irgarol 1051 containing anti-fouling paint was used as reference. Five of the six paints tested were toxic to all or some of the organisms after two weeks of leakage with EC50 ranging from 0.08 to around 2% leakage water and LC50 ranging from 1.1% to 88%. The toxicity of leakage water from these paints was still high after 16 weeks. We conclude that these paints contain substances toxic to common organisms in the coastal Baltic ecosystem. A silicone based paint did not exhibit toxic effects to the two organisms. We recommend that biological tests should be used to identify the most harmful products before they are released on the market.

  9. Extent of fungal growth on fiberglass duct liners with and without biocides under challenging environmental conditions.

    PubMed

    Samimi, Behzad S; Ross, Kristen

    2003-03-01

    Eight brands of fiberglass duct liners, including three that contained biocides, were exposed to challenging environmental conditions that would promote fungal growth. Twenty-four rectangular sheet metal ducts in three groups of eight ducts per group were lined with the eight selected liners. Each group of ducts was exposed to one of the three test conditions within an environmental chamber for a period of 15 days. These conditions were a) 75 percent RH, b) 75 percent RH plus water spray, c) 75 percent RH plus dry nutrient, and d) 75 percent RH plus water plus nutrient. Viable spores of Aspergillus niger were aerosolized into each duct as seed. On the 16th day, air and surface samples for fungal spores were collected from inside ducts. The results of air sampling using N6 sampler and visual inspection indicated that two out of three biocide-containing liners, Permacote and Toughgard, inhibited fungal growth but only under condition A. The third biocide-containing liner, Aeroflex Plus, was effective even when it was wet (conditions A and B). All three biocide-containing liners failed to inhibit fungal growth under conditions C and D. Among the five other types of liners that did not contain biocides, ATCO Flex with a smooth Mylar coating was more preferable, exhibiting lower fungal activity during conditions A, B, and C. All liners failed under condition D when nutrient and water were added together. Surface sampling using adhesive tape failed to produce representative results, apparently due to rough/porous surface of duct liners. It was concluded that duct liners with biocide treatment could be less promoting to microbial growth under high humidity as long as their surfaces remain clean and water-free. A liner with an impermeable and smooth surface seems to be less subject to microbial growth under most conditions than biocide-containing liners having porous and/or rough surfaces.

  10. A New, Sensitive Marine Microalgal Recombinant Biosensor Using Luminescence Monitoring for Toxicity Testing of Antifouling Biocides

    PubMed Central

    Sanchez-Ferandin, Sophie; Leroy, Fanny; Bouget, François-Yves

    2013-01-01

    In this study, we propose the use of the marine green alga Ostreococcus tauri, the smallest free-living eukaryotic cell known to date, as a new luminescent biosensor for toxicity testing in the environment. Diuron and Irgarol 1051, two antifouling biocides commonly encountered in coastal waters, were chosen to test this new biosensor along with two degradation products of diuron. The effects of various concentrations of the antifoulants on four genetic constructs of O. tauri (based on genes involved in photosynthesis, cell cycle, and circadian clock) were compared using 96-well culture microplates and a luminometer to automatically measure luminescence over 3 days. This was compared to growth inhibition of O. tauri wild type under the same conditions. Luminescence appeared to be more sensitive than growth inhibition as an indicator of toxicity. Cyclin-dependent kinase (CDKA), a protein involved in the cell cycle, fused to luciferase (CDKA-Luc) was found to be the most sensitive of the biosensors, allowing an accurate determination of the 50% effective concentration (EC50) after only 2 days (diuron, 5.65 ± 0.44 μg/liter; Irgarol 1015, 0.76 ± 0.10 μg/liter). The effects of the antifoulants on the CDKA-Luc biosensor were then compared to growth inhibition in natural marine phytoplankton. The effective concentrations of diuron and Irgarol 1051 were found to be similar, indicating that this biosensor would be suitable as a reliable ecotoxicological test. The advantage of this biosensor over cell growth inhibition testing is that the process can be easily automated and could provide a high-throughput laboratory approach to perform short-term toxicity tests. The ability to genetically transform and culture recombinant O. tauri gives it huge potential for screening many other toxic compounds. PMID:23144143

  11. Proteomics, and metabolomics: magnetic resonance spectroscopy for the presurgical screening of thyroid nodules.

    PubMed

    Minuto, Michele N; Shintu, Laetitia; Caldarelli, Stefano

    2014-06-01

    We review the progress and state-of-the-art applications of studies in Magnetic Resonance Spectroscopy (MRS) and Imaging as an aid for diagnosis of thyroid lesions of different nature, especially focusing our attention to those lesions that are cytologically undetermined. It appears that the high-resolution of High-Resolution Magic-Angle-Spinning (HRMAS) MRS improves the overall accuracy of the analysis of thyroid lesions to a point that a significant improvement in the diagnosis of cytologically undetermined lesions can be expected. This analysis, in the meantime, allows a more precise comprehension of the alterations in the metabolic pathways induced by the development of the different tumors. Although these results are promising, at the moment, a clinical application of the method to the common workup of thyroid nodules cannot be used, due to both the limitation in the availability of this technology and the wide range of techniques, that are not uniformly used. The coming future will certainly see a wider application of these methods to the clinical practice in patients affected with thyroid nodules and various other neoplastic diseases.

  12. How I report breast magnetic resonance imaging studies for breast cancer staging and screening.

    PubMed

    Vinnicombe, Sarah

    2016-07-25

    Magnetic resonance imaging (MRI) of the breast is the most sensitive imaging technique for the diagnosis and local staging of primary breast cancer and yet, despite the fact that it has been in use for 20 years, there is little evidence that its widespread uncritical adoption has had a positive impact on patient-related outcomes.This has been attributed previously to the low specificity that might be expected with such a sensitive modality, but with modern techniques and protocols, the specificity and positive predictive value for malignancy can exceed that of breast ultrasound and mammography. A more likely explanation is that historically, clinicians have acted on MRI findings and altered surgical plans without prior histological confirmation. Furthermore, modern adjuvant therapy for breast cancer has improved so much that it has become a very tall order to show a an improvement in outcomes such as local recurrence rates.In order to obtain clinically useful information, it is necessary to understand the strengths and weaknesses of the technique and the physiological processes reflected in breast MRI. An appropriate indication for the scan, proper patient preparation and good scan technique, with rigorous quality assurance, are all essential prerequisites for a diagnostically relevant study.The use of recognised descriptors from a standardised lexicon is helpful, since assessment can then dictate subsequent recommendations for management, as in the American College of Radiology BI-RADS (Breast Imaging Reporting and Data System) lexicon (Morris et al., ACR BI-RADS® Atlas, Breast Imaging Reporting and Data System, 2013). It also enables audit of the service. However, perhaps the most critical factor in the generation of a meaningful report is for the reporting radiologist to have a thorough understanding of the clinical question and of the findings that will influence management. This has never been more important than at present, when we are in the throes of a

  13. Determining the biofilm penetrating ability of various biocides utilizing an artificial biofilm matrix

    SciTech Connect

    McIlwaine, D.B.; Diemer, J.; Grab, L.

    1997-12-01

    The efficacy of many commonly used biocides is often determined by laboratory evaluations against a variety of planktonic microorganisms. While these tests provide some information as to the performance of a biocide against a particular microorganism, they may not predict how well the biocide will perform under actual field conditions against the more problematic sissile form of the organisms. In order to address the issue of how well a biocide penetrates and kills the problematic microorganisms contained within a biofilm, an artificial biofilm system utilizing microorganisms embedded in alginate beads has been used to compare the efficacy of biocide treatments against both the planktonic and sessile form of the same organism. Pure cultures of Enterobacter aerogenes, as well as mixed field isolates, were used in the experiments. In addition, the alginate beads were prepared with actual system waters taken from a variety of industrial applications. In that way, all of the scale and corrosion inhibitors and other contaminants which are present in the actual system are also present in the model biofilm system. In all cases, the organisms contained within the artificial biofilm were significantly more difficult to kill than the corresponding planktonic microbes.

  14. Effects of biocides on gene expression in the sulfate-reducing bacterium Desulfovibrio vulgaris Hildenborough.

    PubMed

    Lee, Meng-Hsin Phoebe; Caffrey, Sean M; Voordouw, Johanna K; Voordouw, Gerrit

    2010-07-01

    Although sulfate-reducing bacteria (SRB), such as Desulfovibrio vulgaris Hildenborough (DvH) are often eradicated in oil and gas operations with biocides, such as glutaraldehyde (Glut), tetrakis (hydroxymethyl) phosphonium sulfate (THPS), and benzalkonium chloride (BAC), their response to these agents is not well known. Whole genome microarrays of D. vulgaris treated with biocides well below the minimum inhibitory concentration showed that 256, 96, and 198 genes were responsive to Glut, THPS, and BAC, respectively, and that these three commonly used biocides affect the physiology of the cell quite differently. Glut induces expression of genes required to degrade or refold proteins inactivated by either chemical modification or heat shock, whereas BAC appears to target ribosomal structure. THPS appears to primarily affect energy metabolism of SRB. Mutants constructed for genes strongly up-regulated by Glut, were killed by Glut to a similar degree as the wild type. Hence, it is difficult to achieve increased sensitivity to this biocide by single gene mutations, because Glut affects so many targets. Our results increase understanding of the biocide's mode of action, allowing a more intelligent combination of mechanistically different agents. This can reduce stress on budgets for chemicals and on the environment.

  15. Evaluation of the Biocidal Efficacy of Different Forms of Silver Against Cupriavidus (formerly Wautersia) Species Bacteria

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Schultz, John R.; Wong, Wing; Algate, Michelle T.; Bryant, Becky; Castro, Victoria A.

    2009-01-01

    Contingency Water Containers (CWCs) are used to store potable and technical water that is transferred to the International Space Station (ISS) from the Shuttle orbiter vehicles. When CWCs are filled, water from the orbiter galley is passed through an ion exchange/activated carbon cartridge that removes the residual iodine biocide used on Shuttle before silver biocide is added. Removal of iodine and addition of silver is necessary to inhibit microbial growth inside CWCs and maintain compatibility with the water systems in the Russian segment of ISS. As part of nominal water transfer activities, crewmembers collect samples from several CWCs for postflight analysis. Results from the analysis of water transfer samples collected during the docked phases of STS-118/13A.1 and STS-120/10A showed that several of the CWCs contained up to 10(exp 4) CFU/mL of bacteria despite the fact that the silver concentrations in the CWCs were within acceptable limits. The samples contained pure cultures of a single bacteria, a Cupriavidus (formerly Wautersia) species that has been shown to be resistant to metallic biocides. As part of the investigation into the cause and remediation of the bacterial contamination in these CWCs, ground studies were initiated to evaluate the resistance of the Cupriavidus species to the silver biocides used on ISS and to determine the minimum effective concentration for the different forms of silver present in the biocides. The initial findings from those experiments are discussed herein.

  16. Emission of biocides from treated materials: test procedures for water and air.

    PubMed

    Schoknecht, Ute; Wegner, Robby; Horn, Wolfgang; Jann, Oliver

    2003-01-01

    Methods for the determination of biocide emissions from treated materials into water and air were developed and tested in order to support a comparative ecological assessment of biocidal products. Leaching tests, experiments with simulated rain, extraction cleaning of carpets and emission chamber tests were performed with a series of treated materials. The experiments focused on the effect of changes in the procedure as well as characteristics of the specimens and demonstrate the suitability of the proposed methods for biocides of different product types. It was demonstrated that emissions of biocides into water can be compared on the basis of leaching tests in which the emission kinetics of the active ingredients are recorded. However, the water volume per surface area and the timetable for water changes have to be defined in such tests. Functions of flux rates related to time can be well described for inorganic compounds, whereas modelling of the data is more complicated for organic substances. Emission chamber tests using 20-litre and 23-litre glass exsiccators, originally developed to study volatile organic compounds, were successfully adapted for the investigation of the emission of biocides from treated materials which are usually semi volatile organic compounds. However test parameters and the method of analysis have to be adapted to the substances to be determined. Generally, it was found that the emission curves for the semi volatile organic compounds investigated differ from those of volatile organic compounds.

  17. Towards a more realistic picture of in situ biocide actions: combining physiological and microscopy techniques.

    PubMed

    Speranza, M; Wierzchos, J; De Los Rios, A; Perez-Ortega, S; Souza-Egipsy, V; Ascaso, C

    2012-11-15

    In this study, we combined chlorophyll a fluorescence (ChlaF) measurements, using pulse-amplitude-modulate (PAM) equipment, with scanning electron microscopy in backscattered electron mode (SEM-BSE) and transmission electron microscopy (TEM) images to evaluate the actions of Koretrel at lower concentrations on Verrucaria nigrescens colonising a dolostone. ChlaF measurements are good indicators of the damaging effects of biocides. However, these indicators only provide an incomplete view of the mechanism of biocides used to control biodeterioration agents. The death of the V. nigrescens photobiont at two biocide concentrations was revealed by PAM, SEM-BSE and TEM. Once Koretrel was applied, the Fv/Fm ratios markedly fell in the first few hours after the 1.5% treatment, and ratios for the 3% dilution remained close to zero throughout the study. The algal zone shows the plasmolysed appearance of the photobiont cells, and important aspects related to the action of the biocide on free and lichenised fungi were also detected using SEM-BSE. Many of the mycobiont cells had only their cell walls preserved; although, some fungal hyphae in lichen thalli and some microorganisms in endolithic clusters maintained lipid storage in their cytoplasm. These results indicated that the combination of physiological and microscopy techniques improves the assessment of biocide action in situ and this will help to optimize protocols in order to reduce the emission of these compounds to the environment.

  18. Exploring the sensitivity of the zone of inhibition test for leachable biocides from paper and board food contact materials, and improvements thereof.

    PubMed

    Castle, L; Kelly, J; Jickells, S M; Johns, S M; Mountfort, K A

    2012-01-01

    The zone of inhibition method to test the release of biocides from paper and board food contact materials was evaluated. The method tests the paper by placing a small specimen directly onto culture plates of Bacillus subtilis and Aspergillus niger. The principle is that any extractable biocide will diffuse from the paper into the surrounding nutrient medium and so inhibit growth of the microorganism in the vicinity. The test was found to have insufficient sensitivity for assuring food safety, where detection limits for migration at or below the mg l(-1) (parts per million) level are needed. Also, the test does not mimic the actual or foreseeable conditions of use since most paper/board materials are not intended for direct contact with an aqueous medium for up to 3 days at 30°C (B. subtilis) or 25°C (A. niger), which are the incubation conditions used. The sensitivity of the test was increased approximately 100-fold by preparing a concentrated extract of the paper to be tested and applying this extract to the assay via a blank paper carrier. This was done using methanol as a good solvent for most biocides, as a proof of principle. Other solvents or food simulants could be used to mimic the conditions of use intended for the particular paper/board samples under examination, e.g. contact with dry, fatty, aqueous or acidic foods, hot or cold. Twenty-four plain (unconverted) paper and board samples and 100 food packaging samples were evaluated using the modified procedure. The results revealed that the method has been developed to the stage where background cytotoxic action of normal paper constituents gives a weak response. Unlike the original method, therefore, the modified method with its improved sensitivity and the facility to link with the intended food contact conditions may be considered a suitable bioassay screening test to complement chemical analysis of paper/board for composition and migration.

  19. Theoretical screening of intermetallic ThMn12-type phases for new hard-magnetic compounds with low rare earth content

    PubMed Central

    Körner, Wolfgang; Krugel, Georg; Elsässer, Christian

    2016-01-01

    We report on theoretical investigations of intermetallic phases derived from the ThMn12-type crystal structure. Our computational high-throughput screening (HTS) approach is extended to an estimation of the anisotropy constant K1, the anisotropy field Ha and the energy product (BH)max. The calculation of K1 is fast since it is based on the crystal field parameters and avoids expensive total-energy calculations with many k-points. Thus the HTS approach allows a very efficient search for hard-magnetic materials for which the magnetization M and the coercive field Hc connected to Ha represent the key quantities. Besides for NdFe12N which has the highest magnetization we report HTS results for several intermetallic phases based on Cerium which are interesting as alternative hard-magnetic phases because Cerium is a less ressource-critical element than Neodymium. PMID:27098547

  20. Screening of lipase inhibitors from Scutellaria baicalensis extract using lipase immobilized on magnetic nanoparticles and study on the inhibitory mechanism.

    PubMed

    Wan, Li-Hong; Jiang, Xiao-Lan; Liu, Yi-Ming; Hu, Jin-Jie; Liang, Jian; Liao, Xun

    2016-03-01

    Scutellaria baicalensis is a traditional Chinese medicinal plant possessing a wide variety of biological activities. In this work, lipase immobilized on magnetic nanoparticles (LMNPs) was used as solid phase extract absorbent for screening of lipase inhibitors from this plant. Three flavonoids were found to bind to LMNPs and were identified as baicalin, wogonin, and oroxylin A by liquid chromatography-mass spectrometry (HPLC-MS). Their IC50 values were determined to be 229.22 ± 12.67, 153.71 ± 9.21, and 56.07 ± 4.90 μM, respectively. Fluorescence spectroscopy and molecular docking were used to probe the interactions between these flavonoids and lipase. All the flavonoids quenched the fluorescence of lipase statically by forming new complexes, implying their affinities with the enzyme. The thermodynamic analysis suggested that van der Waals force and hydrogen bond were the main forces between wogonin and lipase, while hydrophobic force was the main force for the other two flavonoids. The results from a molecular docking study further revealed that all of them could insert into the pocket of lipase binding to a couple of amino acid residues.

  1. A novel assay for screening inhibitors targeting HIV-1 integrase dimerization based on Ni-NTA magnetic agarose beads

    PubMed Central

    Zhang, Dawei; He, Hongqiu; Liu, Mengmeng; Meng, Zhixia; Guo, Shunxing

    2016-01-01

    Human immunodeficiency virus (HIV)-1 integrase (IN), which mediates integration of viral cDNA into the cellular chromosome, is a validated antiviral drug target. Three IN inhibitors, raltegravir, elvitegravir and dolutegravir, have been clinically approved since 2008. However, drug resistance have emerged in infected patients receiving treatment using these drugs which share the same mechanism of action and have a low genetic barrier for resistance. Therefore, there is an urgent need to develop drugs with novel mechanism. IN requires a precise and dynamic equilibrium between several oligomeric species for its activities. The modulation of the process which is termed as IN oligomerization, presents an interesting allosteric target for drug development. In this research, we developed a magnetic beads based approach to assay the IN dimerization. Then, using the assay we screened a library of 1000 Food and Drug Administration (FDA)-approved drugs for IN dimerization inhibitors and identified dexlansoprazole as a potential IN dimerization inhibitor. In conclusion, the assay presented here has been proven to be sensitive and specific for the detection of IN dimerization as well as for the identification of antiviral drugs targeting IN dimerization. Moreover, a FDA-approved proton-pump inhibitors, dexlansoprazole, was identified as a potential inhibitor for IN dimerization. PMID:27137477

  2. Inactivation of murine norovirus by chemical biocides on stainless steel

    PubMed Central

    2009-01-01

    Background Human norovirus (NoV) causes more than 80% of nonbacterial gastroenteritis in Europe and the United States. NoV transmission via contaminated surfaces may be significant for the spread of viruses. Therefore, measures for prevention and control, such as surface disinfection, are necessary to interrupt the dissemination of human NoV. Murine norovirus (MNV) as a surrogate for human NoV was used to study the efficacy of active ingredients of chemical disinfectants for virus inactivation on inanimate surfaces. Methods The inactivating properties of different chemical biocides were tested in a quantitative carrier test with stainless steel discs without mechanical action. Vacuum-dried MNV was exposed to different concentrations of alcohols, peracetic acid (PAA) or glutaraldehyde (GDA) for 5 minutes exposure time. Detection of residual virus was determined by endpoint-titration on RAW 264.7 cells. Results PAA [1000 ppm], GDA [2500 ppm], ethanol [50% (v/v)] and 1-propanol [30% (v/v)] were able to inactivate MNV under clean conditions (0.03% BSA) on the carriers by ≥ 4 log10 within 5 minutes exposure time, whereas 2-propanol showed a reduced effectiveness even at 60% (v/v). Furthermore, there were no significant differences in virus reduction whatever interfering substances were used. When testing with ethanol, 1- and 2-propanol, results under clean conditions were nearly the same as in the presence of dirty conditions (0.3% BSA plus 0.3% erythrocytes). Conclusion Products based upon PAA, GDA, ethanol and 1-propanol should be used for NoV inactivation on inanimate surfaces. Our data provide valuable information for the development of strategies to control NoV transmission via surfaces. PMID:19583832

  3. Nanopatterned antimicrobial enzymatic surfaces combining biocidal and fouling release properties

    NASA Astrophysics Data System (ADS)

    Yu, Qian; Ista, Linnea K.; López, Gabriel P.

    2014-04-01

    Surfaces incorporating the antimicrobial enzyme, lysozyme, have been previously demonstrated to effectively disrupt bacterial cellular envelopes. As with any surface active antimicrobial, however, lysozyme-expressing surfaces become limited in their utility by the accumulation of dead bacteria and debris. Surfaces modified with environmentally responsive polymers, on the other hand, have been shown to reversibly attach and release both live and dead bacterial cells. In this work, we combine the antimicrobial activity of lysozyme with the fouling release capability of the thermally responsive polymer, poly(N-isopropylacrylamide) (PNIPAAm), which has a lower critical solution temperature (LCST) in water at ~32 °C. Nanopatterned PNIPAAm brushes were fabricated using interferometric lithography followed by surface-initiated polymerization. Lysozyme was then adsorbed into the polymer-free regions of the substrate between the brushes to achieve a hybrid surface with switchable antimicrobial activity and fouling-release ability in response to the change of temperature. The temperature triggered hydration and conformational change of the nanopatterned PNIPAAm brushes provide the ability to temporally regulate the spatial concealment and exposure of adsorbed lysozyme. The biocidal efficacy and release properties of the hybrid surface were tested against Escherichia coli K12 and Staphylococcus epidermidis. The hybrid surfaces facilitated the attachment of bacteria at 37 °C for E. coli and 25 °C for S. epidermidis and when the temperature is above the LCST, collapsed and dehydrated PNIPAAm chains expose lysozyme to kill attached bacteria. Changing temperature across the LCST of PNIPAAm (e.g. from 37 °C to 25 °C for E. coli or from 25 °C to 37 °C for S. epidermidis) to induce a hydration transition of PNIPAAm promoted the release of dead bacteria and debris from the surfaces upon mild shearing. These results suggest that nano-engineered surfaces can provide an effective

  4. Case Study Of Spatial Magnetic Susceptibility Screening Within The Urban Area Of Tuebingen, SW Germany, As A Proxy For Poly-cyclic Aromatic Hydrocarbon Contamination

    NASA Astrophysics Data System (ADS)

    Blaha, U.; Steidle, D. K.; Hoffmann, V.; Appel, E.; Grathwohl, P.

    In situ magnetic susceptibility screening was performed in the southern part of Tübin- gen city, SW Germany. The main purpose of this case study was to prove the applica- bility of in situ magnetic susceptibility measurements on soils in a variably polluted and densely populated urban environment. Road and rail traffic, house heating and small-scale industry are regarded as the sources of air-borne pollutants in Tübingen city. The impact of any kind of anthropogenic input on soils was studied taking into account specific areas in the city and the topography. A topographical dependence of in situ magnetic susceptibility as well as Shot spotsT of strongly increased values & cedil;were observed. More detailed investigation on selected spots, measuring the suscepti- bility on vertical soil profiles in the laboratory, provided information about the origin of the recorded magnetic signal. Rock magnetic measurements provided additional in- formation about the origin of mineral phases in the soils. PAH (Poly-cyclic Aromatic Hydrocarbon) analyses on selected soil samples revealed a direct link to the observed magnetic susceptibility indicating that magnetic susceptibility might be a proxy for PAH contamination in soils.

  5. Association between the findings on magnetic resonance imaging screening for syringomyelia in asymptomatic Cavalier King Charles spaniels and observation of clinical signs consistent with syringomyelia in later life.

    PubMed

    Ives, E J; Doyle, L; Holmes, M; Williams, T L; Vanhaesebrouck, A E

    2015-01-01

    A questionnaire-based study was used to investigate the association between the findings on magnetic resonance imaging (MRI) screening for syringomyelia (SM) in 79 asymptomatic Cavalier King Charles spaniels (CKCS) and the subsequent development of clinical signs consistent with SM in later life. Owners reported clinical signs consistent with SM in 13/79 (16%) dogs at the time of the questionnaire. A significantly greater proportion of CKCS with a syrinx visible on MRI screening showed clinical signs in later life (9/25, 36%) than dogs without a visible syrinx (4/54, 7%; odds ratio 6.9). Whether the findings of MRI screening can be used to indicate the likelihood of an asymptomatic CKCS developing clinical signs consistent with SM in later life warrants further prospective study in a larger cohort of dogs.

  6. Magnetic Resonance Imaging as an Adjunct to Mammography for Breast Cancer Screening in Women at Less Than High Risk for Breast Cancer: A Health Technology Assessment

    PubMed Central

    Nikitovic-Jokic, Milica; Holubowich, Corinne

    2016-01-01

    Background Screening with mammography can detect breast cancer early, before clinical symptoms appear. Some cancers, however, are not captured with mammography screening alone. Among women at high risk for breast cancer, magnetic resonance imaging (MRI) has been suggested as a safe adjunct (supplemental) screening tool that can detect breast cancers missed on screening mammography, potentially reducing the number of deaths associated with the disease. However, the use of adjunct screening tests may also increase the number of false-positive test results, which may lead to unnecessary follow-up testing, as well as patient stress and anxiety. We investigated the benefits and harms of MRI as an adjunct to mammography compared with mammography alone for screening women at less than high risk (average or higher than average risk) for breast cancer. Methods We searched Ovid MEDLINE, Ovid Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), Centre for Reviews and Dissemination (CRD) Health Technology Assessment Database, and National Health Service (NHS) Economic Evaluation Database, from January 2002 to January 2016, for evidence of effectiveness, harms, and diagnostic accuracy. Only studies evaluating the use of screening breast MRI as an adjunct to mammography in the specified populations were included. Results No studies in women at less than high risk for breast cancer met our inclusion criteria. Conclusions It remains uncertain if the use of adjunct screening breast MRI in women at less than high risk (average or higher than average risk) for breast cancer will reduce breast cancer–related mortality without significant increases in unnecessary follow-up testing and treatment. PMID:27990198

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

    PubMed

    Xue, Yuan; Voordouw, Gerrit

    2015-01-01

    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 (PV) 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.

  8. Biocide and antibiotic resistance of Enterococcus faecalis and Enterococcus faecium isolated from the swine meat chain.

    PubMed

    Rizzotti, Lucia; Rossi, Franca; Torriani, Sandra

    2016-12-01

    In this study nine strains of Enterococcus faecalis and 12 strains of Enterococcus faecium, isolated from different sample types in the swine meat chain and previously characterized for the presence of antibiotic resistance genes, were examined for phenotypic tolerance to seven biocides (chlorexidine, benzalkonium chloride, triclosan, sodium hypochlorite, 2-propanol, formaldehyde and hydrogen peroxide) and resistance to nine antibiotics (ampicillin, vancomycin, gentamicin, kanamycin, streptomycin, erythromycin, clindamycin, tetracycline and chloramphenicol). Moreover, the presence of efflux system encoding genes qacA/B, qacC, qacE, qacEΔ1, emeA, and stress response genes, sigV and gsp65, involved in the tolerance to biocides, was analysed. Most strains were not tolerant to the biocides, but showed minimum inhibitory concentrations (MICs) higher than the recommended cut-off values for all the antibiotics tested, except for vancomycin and chloramphenicol. Only weak correlations, if any, were found between biocide and antibiotic resistance data. One E. faecalis strain was tolerant to triclosan and one E. faecium strain, with higher tolerance to chlorexidine than the other strains tested, was found to carry a qacA/B gene. Our results indicated that phenotypic resistance to antibiotics is very frequent in enterococcal isolates from the swine meat chain, but phenotypic tolerance to biocides is not common. On the other hand, the gene qacA/B was found for the first time in the species E. faecium, an indication of the necessity to adopt measures suitable to control the spread of biocide resistance determinants among enterococci.

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

    PubMed Central

    Xue, Yuan; Voordouw, Gerrit

    2015-01-01

    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 (PV) 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. PMID:26696994

  10. Developmental neurotoxicity of different classes of biocides in PC-12 cells in vitro.

    PubMed

    Christen, Verena; Rusconi, Manuel; Crettaz, Pierre; Fent, Karl

    2017-04-03

    The detection of developmental neurotoxicity (DNT) of chemicals has high relevance for protection of human health. However, DNT of many biocides is only little known. Furthermore, validated in vitro systems for assessment of DNT are not well established. Here we employed the rat phaeochromocytoma cell line PC-12 to evaluate DNT of 18 frequently used biocides of different classes, including neonicotinoids, pyrethroids, organophosphates, organochlorines, quaternary ammonium compounds, the biocidal active substance piperonylbutoxide, as well as the insect repellent DEET. We determined the outgrowth of neurites in PC-12 cells co-treated with nerve growth factor and different concentrations of biocides for 5days. Furthermore, we determined transcriptional alterations of selected genes that may be associated with DNT, such as camk2α and camk2β, gap-43, neurofilament-h, tubulin-α and tubulin-β. Strong and dose dependent inhibition of neurite outgrowth was induced by azamethiphos and chlorpyrifos, dieldrin and heptachlor, which was correlated with up-regulation of gap-43. No or only weak effects on neurite outgrowth and transcriptional alterations occurred for neonicotinoids acetamiprid, clothianidin, imidacloprid and thiamethoxam, pyrethroids λ-cyhalothrin, cyfluthrin, deltamethrin, and permethrin, the biocidal disinfectants C12-C14-alkyl(ethylbenzyl)dimethylammonium (BAC), benzalkonium chloride and barquat (dimethyl benzyl ammonium chloride), and piperonylbutoxide and diethyltoluamide (DEET). Our study confirms potential developmental neurotoxicity of some biocides and provides first evidence that azamethiphos has the potential to act as a developmental neurotoxic compound. We also demonstrate that inhibition of neurite outgrowth and transcriptional alterations of gap-43 expression correlate, which suggests the employment of gap-43 expression as a biomarker for detection and initial evaluation of potential DNT of chemicals.

  11. Screening of antifouling biocides around a pleasure boat marina in the Baltic Sea after legal restrictions.

    PubMed

    Kylin, Henrik; Haglund, Kurt

    2010-10-01

    Copper, zinc, and Irgarol 1051 concentrations were determined around a pleasure boat marina in the Stockholm Archipelago. Copper concentrations in water were twice as high (6.62 μg L⁻¹) in 2004 as 1992-1993, zinc concentrations six times higher (20.0 μg L⁻¹). Concentrations in bladder wrack (Fucus vesiculosus) had also risen. Irgarol concentrations in water were similar (~0.17 μg L⁻¹) in 1996 and 2004, while concentrations in bladder wrack halved from 1993 to 2004. The peak concentrations of copper and Irgarol in water have shifted indicating that the main source in the 1990 s were local boats, but in 2004 visiting boats.

  12. Screening for Cardiac Magnetic Resonance Scar Features by 12-lead ECG, in Patients with Preserved Ejection Fraction

    PubMed Central

    Mewton, Nathan; Strauss, David G.; Rizzi, Patricia; Verrier, Richard L.; Liu, Chia Ying; Tereshchenko, Larisa G.; Nearing, Bruce; Volpe, Gustavo J.; Marchlinski, Francis E.; Moxley, John; Killian, Tony; Wu, Katherine C.; Spooner, Peter; Lima, João A.C.

    2015-01-01

    Background Increased QRS score and wide spatial QRS-T angle are independent predictors of cardiovascular mortality in the general population. Our main objective was to assess whether a QRS score ≥5 and/or QRS-T angle ≥105° enable screening of patients for myocardial scar features. Methods 77 patients age ≤70 years with QRS score ≥5 AND/OR spatial QRS-T angle ≥105° as well as left ventricular ejection fraction (LVEF) >35% were enrolled in the study. All participants underwent complete clinical examination, signal averaged ECG (SAECG), 30-minute ambulatory ECG recording for T wave alternans (TWA), and late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Relationship between QRS score, QRS-T angle with scar presence and pattern, as well as gray zone, core, and total scar size by LGE-CMR were assessed. Results Myocardial scar was present in 41 (53%) patients, of whom 19 (46%) exhibited a typical ischemic pattern. QRS score but not QRS-T angle was related to total scar size and gray zone size (R2=0.12, P=0.002; R2=0.17; P ≤0.0001 respectively). Patients with QRS scores ≥6 had significantly greater myocardial scar and gray zone size, increased QRS duration and QRS-T angle, a higher prevalence of late potentials (LP) presence, increased LV end-diastolic volume and decreased LVEF. There was a significant independent and positive association between TWA value and total scar (P=0.001) and gray zone size (P=0.01). Conclusion Patients with preserved LVEF and myocardial scar by CMR also have electrocardiographic features that could be involved in ventricular arrhythmogenesis. PMID:26806840

  13. A Label-Free Impedance Immunosensor Using Screen-Printed Interdigitated Electrodes and Magnetic Nanobeads for the Detection of E. coli O157:H7.

    PubMed

    Wang, Ronghui; Lum, Jacob; Callaway, Zach; Lin, Jianhan; Bottje, Walter; Li, Yanbin

    2015-12-15

    Escherichia coli O157:H7 is one of the leading bacterial pathogens causing foodborne illness. In this study, an impedance immunosensor based on the use of magnetic nanobeads and screen-printed interdigitated electrodes was developed for the rapid detection of E. coli O157:H7. Magnetic nanobeads coated with anti-E. coli antibody were mixed with an E. coli sample and used to isolate and concentrate the bacterial cells. The sample was suspended in redox probe solution and placed onto a screen-printed interdigitated electrode. A magnetic field was applied to concentrate the cells on the surface of the electrode and the impedance was measured. The impedance immunosensor could detect E. coli O157:H7 at a concentration of 10(4.45) cfu·mL(-1) (~1400 bacterial cells in the applied volume of 25 μL) in less than 1 h without pre-enrichment. A linear relationship between bacteria concentration and impedance value was obtained between 10(4.45) cfu·mL(-1) and 10(7) cfu·mL(-1). Though impedance measurement was carried out in the presence of a redox probe, analysis of the equivalent circuit model showed that the impedance change was primarily due to two elements: Double layer capacitance and resistance due to electrode surface roughness. The magnetic field and impedance were simulated using COMSOL Multiphysics software.

  14. A Label-Free Impedance Immunosensor Using Screen-Printed Interdigitated Electrodes and Magnetic Nanobeads for the Detection of E. coli O157:H7

    PubMed Central

    Wang, Ronghui; Lum, Jacob; Callaway, Zach; Lin, Jianhan; Bottje, Walter; Li, Yanbin

    2015-01-01

    Escherichia coli O157:H7 is one of the leading bacterial pathogens causing foodborne illness. In this study, an impedance immunosensor based on the use of magnetic nanobeads and screen-printed interdigitated electrodes was developed for the rapid detection of E. coli O157:H7. Magnetic nanobeads coated with anti-E. coli antibody were mixed with an E. coli sample and used to isolate and concentrate the bacterial cells. The sample was suspended in redox probe solution and placed onto a screen-printed interdigitated electrode. A magnetic field was applied to concentrate the cells on the surface of the electrode and the impedance was measured. The impedance immunosensor could detect E. coli O157:H7 at a concentration of 104.45 cfu·mL−1 (~1400 bacterial cells in the applied volume of 25 μL) in less than 1 h without pre-enrichment. A linear relationship between bacteria concentration and impedance value was obtained between 104 cfu·mL−1 and 107 cfu·mL−1. Though impedance measurement was carried out in the presence of a redox probe, analysis of the equivalent circuit model showed that the impedance change was primarily due to two elements: Double layer capacitance and resistance due to electrode surface roughness. The magnetic field and impedance were simulated using COMSOL Multiphysics software. PMID:26694478

  15. Comparative surface antimicrobial properties of synthetic biocides and novel human apolipoprotein E derived antimicrobial peptides.

    PubMed

    Forbes, Sarah; McBain, Andrew J; Felton-Smith, Susan; Jowitt, Thomas A; Birchenough, Holly L; Dobson, Curtis B

    2013-07-01

    Medical device infection remains a major clinical concern. Biocidal compounds have been incorporated into medical device materials ideally to inhibit bacterial colonisation whilst exhibiting relatively low cytotoxicity. We compared the antibacterial activity, anti-biofilm efficacy and cytotoxicity of a novel peptide derivative of human apolipoprotein E (apoEdpL-W) to that of commonly used biocides, before and after coating onto a range of standard polymers. Since the antimicrobial function of most biocides frequently involves associations with cellular membranes, we have also studied the detailed interactions of the test antimicrobials with phospholipid bilayers, using the quartz crystal microbalance device combined with dual-polarisation interferometry. ApoEdpL-W displayed broad-spectrum antibacterial activity and marked efficacy against nascent Staphylococcus aureus biofilms. Compounds showed better antimicrobial activity when combined with hydrogel materials than with non-porous materials. The membrane interactions of apoEdpL-W were most similar to that of PHMB, with both agents appearing to readily bind and insert into lipid bilayers, possibly forming pores. However apoEdpL-W showed lower cytotoxicity than PHMB, its efficacy was less affected by the presence of serum, and it demonstrated the highest level of biocompatibility of all the biocides, as indicated by our measurement of its antimicrobial biocompatibility index. This work shows the potential of apoEdpL-W as an effective antiseptic coating agent.

  16. Susceptibility of 194 Salmonella Isolates to 17 Chemicals used as Sanitizers and Biocides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salmonella is a major cause of foodborne illnesses in the United States. Meat processing facilities use a wide variety of antimicrobial interventions to reduce Salmonella contamination. The objective of this study was to determine the minimum inhibitory concentration (MIC) of sanitizers and biocides...

  17. Biocide and antimicrobial susceptibility of methicillin-resistant staphylococcal isolates from horses.

    PubMed

    Couto, Natacha; Belas, Adriana; Tilley, Paula; Couto, Isabel; Gama, Luís T; Kadlec, Kristina; Schwarz, Stefan; Pomba, Constança

    2013-09-27

    The aim of this study was to evaluate the biocide and antimicrobial susceptibility of methicillin-resistant staphylococcal isolates from horses. Fourteen methicillin-resistant staphylococci (MRS) were subjected to an extensive genotype characterization, including SCCmec, dru, spa, PFGE and MLST typing. Antimicrobial susceptibility testing was performed and resistance genes were detected by PCR. Minimum bactericidal concentrations (MBCs) of four biocides [chlorhexidine acetate (CHA), benzalkonium chloride (BAC), triclosan (TCL) and glutaraldehyde (GLA)] were determined following the recommendations of document NF EN 1040. The presence of qac and sh-fabI genes was investigated by PCR. Several antimicrobial resistance patterns and genes were detected. When MRS strains were exposed for a longer period of time, a lower concentration of the biocide was needed to achieve lethality. TCL had the lowest MBC values. All MBC values were lower than the recommended in-use concentrations for veterinary medicine. S. haemolyticus and S. cohnii subsp. cohnii carried plasmid-borne qacA and sh-fabI or qacB and a qacH-like genes, respectively. Biocides appear to be a reliable antiseptic option against MRS, since even in the presence of bacterial efflux mechanisms, the recommended concentration is much higher than the in vitro MBC.

  18. THE BIOCIDE TRIBUTYLTIN ALTERS TESTOSTERONE ESTERIFICATION IN MUD SNAILS (ILYANASSA OBSOLETA)

    EPA Science Inventory

    The Biocide Tributyltin Alters Testosterone Esterification in Mud Snails (Ilyanassa obsoleta)

    Meredith P. Gooding and Gerald A. LeBlanc
    Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633

    Tributyltin (TBT...

  19. Potential Impact of Increased Use of Biocides in Consumer Products on Prevalence of Antibiotic Resistance

    PubMed Central

    Gilbert, Peter; McBain, Andrew J.

    2003-01-01

    There has recently been much controversy surrounding the increased use of antibacterial substances in a wide range of consumer products and the possibility that, as with antibiotics, indiscriminate use of biocides might contribute to the overall pattern of susceptibility in the general environment and in the clinic. Such speculation, based on the isolation of resistant mutants from in vitro monoculture experiments, is not reflected by an emergence of biocide-resistant strains in vivo. This review provides a broad coverage of the biocide and resistance literature and evaluates the potential risks, perceived from such laboratory monoculture experiments, against evidence gathered over 50 years of field studies. An explanation for the continued effectiveness of broad-spectrum biocidal agents against the decline in efficacy of therapeutic agents is provided based on the fitness costs of resistance and the ubiquity of naturally occurring substances that possess antibacterial effect. While we conclude from this review of the literature that the incorporation of antibacterial agents into a widening sphere of personal products has had little or no impact on the patterns of microbial susceptibility observed in the environment, the associated risks remain finite. The use of such products should therefore be associated with a clear demonstration of added value either to consumer health or to the product life. Hygienic products should therefore be targeted to applications for which the risks have been established. PMID:12692093

  20. Correlation between antibiotic and biocide resistance in mesophilic and psychrotrophic Pseudomonas spp. isolated from slaughterhouse surfaces throughout meat chain production.

    PubMed

    Lavilla Lerma, Leyre; Benomar, Nabil; Casado Muñoz, María del Carmen; Gálvez, Antonio; Abriouel, Hikmate

    2015-10-01

    The aim of this study was to evaluate biocide susceptibility in mesophilic and psychrotrophic pseudomonads isolated from surfaces of a goat and lamb slaughterhouse, which was representative of the region. To determine biocide resistance in pseudomonads, we determined for the first time the epidemiological cut-off values (ECOFFs) of benzalkonium, cetrimide, chlorhexidine, hexachlorophene, P3 oxonia, polyhexamethylene guanidine hydrochloride (PHMG), topax 66 and triclosan being generally very similar in different Pseudomonas spp. with some exceptions. Thus, resistance of pseudomonads was mainly shown to triclosan, and in lesser extent to cetrimide and benzalkonium chloride depending on the species, however they were highly susceptible to industrial formulations of biocides. By means of statistical analysis, positive correlations between antibiotics, biocides and both antimicrobials in pseudomonads were detected suggesting a co- or cross resistance between different antimicrobials in goat and lamb slaughterhouse environment. Cross-resistance between biocides and antibiotics in pseudomonads were especially detected between PHMG or triclosan and different antibiotics depending on the biocide and the population type. Thus, the use of those biocides as disinfectant in slaughterhouse zones must be carefully evaluated because of the selection pressure effect of antimicrobials on the emergence of resistant bacteria which could be spread to the consumer. It is noteworthy that specific industrial formulations such as topax 66 and oxonia P3 showed few correlations with antibiotics (none or 1-2 antibiotics) which should be taken into consideration for disinfection practices in goat and lamb slaughterhouse.

  1. Dermal permeation of biocides and aromatic chemicals in three generic formulations of metalworking fluids.

    PubMed

    Vijay, Vikrant; White, Eugene M; Kaminski, Michael D; Riviere, Jim E; Baynes, Ronald E

    2009-01-01

    Metalworking fluids (MWF) are complex mixtures consisting of a variety of components and additives. A lack of scientific data exists regarding the dermal permeation of its components, particularly biocides. The aim of this study was to evaluate the dermal permeation of biocides and other aromatic chemicals in water and in three generic soluble oil, semi-synthetic, and synthetic MWF types in order to evaluate any differences in their permeation profiles. An in vitro flow-through diffusion cell study was performed to determine dermal permeation. An infinite dose of different groups of chemicals (6 biocides and 29 aromatic chemicals) was applied to porcine skin, with perfusate samples being collected over an 8-h period. Perfusate samples were analyzed by gas chromatography/mass spectrometry (GC-MS) and ultra-performance liquid chromatography/mass spectroscopy (UPLC-MS), and permeability was calculated from the analysis of the permeated chemical concentration-time profile. In general, the permeation of chemicals was highest in aqueous solution, followed by synthetic, semi-synthetic, and soluble oil MWF. The absorption profiles of most of the chemicals including six biocides were statistically different among the synthetic and soluble oil MWF formulations, with reduced permeation occurring in oily formulations. Permeation of almost all chemicals was statistically different between aqueous and three MWF formulation types. Data from this study show that permeation of chemicals is higher in a generic synthetic MWF when compared to a soluble oil MWF. This indicates that a soluble oil MWF may be safer than a synthetic MWF in regard to dermal permeation of chemicals to allow for an increased potential of systemic toxicity. Therefore, one may conclude that a synthetic type of formulation has more potential to produce contact dermatitis and induce systemic toxicological effects. The dilution of these MWF formulations with water may increase dermal permeability of biocides

  2. Adhesion and biocides inactivation of Salmonella on stainless steel and polyethylene

    PubMed Central

    Tondo, Eduardo Cesar; Machado, Taís Raquel Marcon; Malheiros, Patrícia da Silva; Padrão, Débora Kruger; de Carvalho, Ana Lyl; Brandelli, Adriano

    2010-01-01

    The adhesion of Salmonella (S.) strains to stainless steel and polyethylene and their inactivation by biocides used in food industry was investigated. Coupons of stainless steel and polyethylene were immersed in bacterial suspensions of S. Enteritidis, S. Typhimurium, and S. Bredeney during 15, 30, and 60 minutes, and submitted to different concentrations of peracetic acid (PAA), sodium hypochlorite (NaOCl), and quaternary ammonium (Quat) sanitizers. Hydrophobicity of the surfaces was evaluated by contact angle measurements using the sessile drop method and bacterial adhesion was accompanied through bacterial counts and scanning electron microscopy (SEM). Results indicated that the three serovars of Salmonella presented similar adhesion to both materials (5.0 to 6.5 log cfu cm-2). The time of exposure did not influence the counts of adhered cells on both surfaces, however SEM revealed larger clusters of S. Enteritidis on both materials, not found for the other serovars. S. Enteritidis presented lower sessile drop angle on polyethylene, indicating hydrophilic properties of this material. The biocides were not able to inactivate all the microorganisms adhered on both surfaces. At least 1 log cfu cm-2 of all serovars tested remained viable after the exposure to different biocide concentrations. In general, higher counts of survivors were observed on polyethylene disinfected with different concentrations of biocides. S. Bredeney e S. Typhimurium were more resistant than S. Enteritidis to PAA, whilst S. Enteritidis presented smaller reduction rates to NaOCl. This last biocide was able to reduce Salmonella counts in approximately 3.0 to 4.0 log cm-2. When adhered to polyethylene, the serovars S. Typhimurium and S. Enteritidis were more resistant to Quat than S. Bredeney in all concentrations tested, and the numbers of S. Enteritidis remained almost unaltered. On stainless steel disinfected by Quat, S. Bredeney presented higher numbers of survivors. PMID:24031583

  3. The effects of biocides (antiseptics and disinfectants) on the endospores of Rhinosporidium seeberi.

    PubMed

    Arseculeratne, S N; Atapattu, D N; Balasooriya, P; Fernando, R

    2006-04-01

    No data exists on the activity of biocides (antiseptics and disinfectants) on Rhinosporidium seeberi that causes rhinosporidiosis in humans and animals. On account of the inability to culture R. seeberi, in vitro, dyes were used to assess the morphological integrity and viability of biocide-treated endospores that are considered to be the infective stage of this pathogen. Evan's Blue (EvB) identifies the morphological integrity of the endospores while MTT (3-[4, 5-dimethylthiazol-2yl]-2, 5-diphenyl tetrazolium bromide) identifies metabolic activity through its reduction by cellular dehydrogenases to microscopically visible deposits of insoluble formazan. MTT-negativity has earlier been shown to correlate with absence of growth of yeast and mycelial fungi in culture and could thus indicate the loss of viability of MTT-negative rhinosporidial endospores. Hydrogen peroxide, glutaraldehyde, chloroxylenol, chlorhexidine, cetrimide, thimerosal, 70% ethanol, iodine in 70% ethanol, 10% formalin, povidone-iodine, sodium azide and silver nitrate were tested on freshly-harvested endospores and all biocides caused metabolic inactivation with or without altered structural integrity as shown by absence of MTT-staining after 3, 24 or 36 hour after exposure, while EvB stained only the endospores treated with sodium azide, ethanol, thimerosal, chloroxylenol, glutaraldehyde and hydrogen peroxide. With clinically useful biocides - chlorhexidine, cetrimide-chlorhexidine, 70% ethanol, povidone-iodine and silver nitrate, a total period of exposure of endospores to the biocide, for seven minutes, produced metabolic inactivation of the endospores. Anti-rhinosporidial antiseptics that could be used in surgery on rhinosporidial patients include povidone-iodine in nasal packs for nasal and naso-pharyngeal surgery, chlorhexidine and cetrimide-chlorhexidine on the skin, while povidone-iodine and silver nitrate could have application in ocular rhinosporidiosis.

  4. Rapid screening and identification of α-glucosidase inhibitors from mulberry leaves using enzyme-immobilized magnetic beads coupled with HPLC/MS and NMR.

    PubMed

    Tao, Yi; Zhang, Yufeng; Cheng, Yiyu; Wang, Yi

    2013-02-01

    α-Glucosidase plays important roles in the digestion and absorption of carbohydrates in the small intestine. The inhibition of α-glucosidase is regarded as a potential way to treat diabetes. We established an approach to screening α-glucosidase inhibitors from medicinal plants using enzyme-coated magnetic bead. Using 1-(3-dimethyl-aminopropyl)-3-ethylcarbodiimide and N-hydroxysuccinimide as reaction reagents, α-glucosidase was immobilized on the magnetic beads by covalent linkage. The conjugation of α-glucosidase to the magnetic beads was characterized using scanning electron microscope and X-ray diffractometer. The proposed approach was applied in fishing potential α-glucosidase inhibitors from extract of Morus alba, a Chinese medicinal plant. The structures of potential active compounds were identified via liquid chromatography-mass spectrometry and nuclear magnetic resonance. The results demonstrated that two flavonoids (isoquercitrin and astragalin) could bind to α-glucosidase, which was confirmed via conventional α-glucosidase inhibitory assay. Our findings suggested that enzyme-coated magnetic beads may be suitable for discovering active compounds from medicinal plants.

  5. Rapid screening and identification of α-amylase inhibitors from Garcinia xanthochymus using enzyme-immobilized magnetic nanoparticles coupled with HPLC and MS.

    PubMed

    Li, Yunfang; Chen, Yu; Xiao, Chuying; Chen, Dan; Xiao, Yuxiu; Mei, Zhinan

    2014-06-01

    α-Amylase inhibitors play an important role in management of diabetes and obesity. In order to rapidly discover potent α-amylase inhibitors from medicinal plants, a ligands-screening method based on enzyme-immobilized magnetic nanoparticles integrated with HPLC was developed. Amine-terminated magnetic nanoparticles were prepared for the immobilization of α-amylase. Based on the affinity theory, the α-amylase-coated magnetic nanoparticles were employed to fish out the ligands from the extracts of Garcinia xanthochymus, and the elutes were examined by HPLC. As a result, three ligands were screened out. Isolation and identification were carried out subsequently. By analyzing the UV, MS and NMR spectra, they were identified as three biflavonoids including GB2a glucoside (2), GB2a (3) and fukugetin (4). The IC50 values of the three compounds were also determined. The results suggest the proposed approach is efficient and accurate, and has great potential in rapid discovery of drug candidates from medical plants.

  6. Development of environmentally-benign wood preservatives based on the combination of organic biocides with antioxidants and metal chelators.

    PubMed

    Schultz, Tor P; Nicholas, Darrel D

    2002-11-01

    Wood extractives can be envisaged to protect heartwood by at least three different mechanisms, i.e. fungicide, free radical scavengers/antioxidants and as metal chelators. In short-term laboratory decay tests using two different wood species and decay fungi, the combination of different organic fungicides with various antioxidants and/or metal chelators gave enhanced activity as compared to the organic biocide alone, with the best results usually obtained with all three compounds. Outdoor ground-contact stakes treated with a biocide and antioxidant combination and exposed for 30 months also gave enhanced protection against both decay fungi and termites. It was concluded that the combination of an organic biocide with metal chelating and/or antioxidant additives gives enhanced protection to wood against fungi as compared to the biocide alone and, consequently, it may be possible to develop environmentally-benign wood preservative systems based on this idea.

  7. The effect of seasonal changes on the selection of biocide inhibitors for Arabian Gulf seawater for water injection purposes

    SciTech Connect

    Al-Hashem, A.; Salman, M.; Al-Muhanna, K.; Al-Bazzaz, W.

    1997-08-01

    This investigation was carried out to determine the most effective biocide inhibitor for Northern Arabian Gulf Seawater. This seawater will be used for water injection purposes for some oil fields in Kuwait. Arabian Gulf Seawater is known to be very saline during the summer months and less saline during the rainy season of spring. The biocide inhibitors were tested in a rig with six side streams biofouling monitoring tubes (SBMT). Bacterial nutrients were added to the system and carbon steel studs were placed along the tubes of the biocide evaluation test rig (BETR). After a month, a thin, slimy, and black deposit was formed on the carbon steel studs. The deposit contained 107 general aerobic bacteria (GAB), 107 general anaerobic bacteria (GAnB) and 105 sulfate reducing bacteria (SRB). The most effective biocide inhibitor was found to be a fatty amine aryl quaternary inhibitor at 50% dosage.

  8. The Role of Preoperative Magnetic Resonance Imaging in the Assessment and Surgical Treatment of Interval and Screen-Detected Breast Cancer in Older Women.

    PubMed

    Goodrich, Martha E; Weiss, Julie; Onega, Tracy; Balch, Steve L; Buist, Diana S M; Kerlikowske, Karla; Henderson, Louise M; Hubbard, Rebecca A

    2016-11-01

    We describe the relationship between preoperative magnetic resonance imaging (MRI) and the utilization of additional imaging, biopsy, and primary surgical treatment for subgroups of women with interval versus screen-detected breast cancer. We determined the proportion of women receiving additional breast imaging or biopsy and type of primary surgical treatment, stratified by use of preoperative MRI, separately for both groups. Using Breast Cancer Surveillance Consortium (BCSC) data, we identified a cohort of women age 66 and older with an interval or screen-detected breast cancer diagnosis between 2005 and 2010. Using logistic regression, we explored associations between primary surgical treatment type and preoperative MRI use for interval and screen-detected cancers. There were 204 women with an interval cancer and 1,254 with a screen-detected cancer. The interval cancer group was more likely to receive preoperative MRI (21% versus 13%). In both groups, women receiving MRI were more likely to receive additional imaging and/or biopsy. Receipt of MRI was not associated with increased odds of mastectomy (OR = 0.99, 95% CI: 0.67-1.50), while interval cancer diagnosis was associated with significantly higher odds of mastectomy (OR = 1.64, 95% CI: 1.11-2.42). Older women with interval cancer were more likely than women with a screen-detected cancer to have preoperative MRI, however, those with an interval cancer had 64% higher odds of mastectomy regardless of receipt of MRI. Given women with interval cancer are reported to have a worse prognosis, more research is needed to understand effectiveness of imaging modalities and treatment consequences within this group.

  9. Inhibitory Effect of Biocides on the Viable Masses and Matrices of Staphylococcus aureus and Pseudomonas aeruginosa Biofilms▿

    PubMed Central

    Toté, K.; Horemans, T.; Berghe, D. Vanden; Maes, L.; Cos, P.

    2010-01-01

    Bacteria and matrix are essential for the development of biofilms, and assays should therefore target both components. The current European guidelines for biocidal efficacy testing are not adequate for sessile microorganisms; hence, alternative discriminatory test protocols should be used. The activities of a broad range of biocides on Staphylococcus aureus and Pseudomonas aeruginosa biofilms were evaluated using such in vitro assays. Nearly all selected biocides showed a significant decrease in S. aureus biofilm viability, with sodium hypochlorite and peracetic acid as the most active biocides. Only hydrogen peroxide and sodium hypochlorite showed some inhibitory effect on the matrix. Treatment of P. aeruginosa biofilms was roughly comparable to that of S. aureus biofilms. Peracetic acid was the most active on viable mass within 1 min of contact. Isopropanol ensured a greater than 99.999% reduction of P. aeruginosa viability after at least 30 min of contact. Comparable to results with S. aureus, sodium hypochlorite and hydrogen peroxide markedly reduced the P. aeruginosa matrix. This study clearly demonstrated that despite their aspecific mechanisms of action, most biocides were active only against biofilm bacteria, leaving the matrix undisturbed. Only hydrogen peroxide and sodium hypochlorite were active on both the biofilm matrix and the viable mass, making them the better antibiofilm agents. In addition, this study emphasizes the need for updated and standardized guidelines for biofilm susceptibility testing of biocides. PMID:20363795

  10. Comprehensive Evaluation of Biological Growth Control by Chlorine-Based Biocides in Power Plant Cooling Systems Using Tertiary Effluent

    PubMed Central

    Chien, Shih-Hsiang; Dzombak, David A.; Vidic, Radisav D.

    2013-01-01

    Abstract Recent studies have shown that treated municipal wastewater can be a reliable cooling water alternative to fresh water. However, elevated nutrient concentration and microbial population in wastewater lead to aggressive biological proliferation in the cooling system. Three chlorine-based biocides were evaluated for the control of biological growth in cooling systems using tertiary treated wastewater as makeup, based on their biocidal efficiency and cost-effectiveness. Optimal chemical regimens for achieving successful biological growth control were elucidated based on batch-, bench-, and pilot-scale experiments. Biocide usage and biological activity in planktonic and sessile phases were carefully monitored to understand biological growth potential and biocidal efficiency of the three disinfectants in this particular environment. Water parameters, such as temperature, cycles of concentration, and ammonia concentration in recirculating water, critically affected the biocide performance in recirculating cooling systems. Bench-scale recirculating tests were shown to adequately predict the biocide residual required for a pilot-scale cooling system. Optimal residuals needed for proper biological growth control were 1, 2–3, and 0.5–1 mg/L as Cl2 for NaOCl, preformed NH2Cl, and ClO2, respectively. Pilot-scale tests also revealed that Legionella pneumophila was absent from these cooling systems when using the disinfectants evaluated in this study. Cost analysis showed that NaOCl is the most cost-effective for controlling biological growth in power plant recirculating cooling systems using tertiary-treated wastewater as makeup. PMID:23781129

  11. Construction of a D-amino acid oxidase reactor based on magnetic nanoparticles modified by a reactive polymer and its application in screening enzyme inhibitors.

    PubMed

    Mu, Xiaoyu; Qiao, Juan; Qi, Li; Liu, Ying; Ma, Huimin

    2014-08-13

    Developing facile and high-throughput methods for exploring pharmacological inhibitors of D-amino acid oxidase (DAAO) has triggered increasing interest. In this work, DAAO was immobilized on the magnetic nanoparticles, which were modified by a biocompatible reactive polymer, poly(glycidyl methacrylate) (PGMA) via an atom transfer radical polymerization technique. Interestingly, the enzyme immobilization process was greatly promoted with the assistance of a lithium perchlorate catalyst. Meanwhile, a new amino acid ionic liquid (AAIL) was successfully synthesized and employed as the efficient chiral ligand in a chiral ligand exchange capillary electrophoresis (CLE-CE) system for chiral separation of amino acids (AAs) and quantitation of methionine, which was selected as the substrate of DAAO. Then, the apparent Michaelis-Menten constants in the enzyme system were determined with the proposed CLE-CE method. The prepared DAAO-PGMA-Fe3O4 nanoparticles exhibited excellent reusability and good stability. Moreover, the enzyme reactor was successfully applied in screening DAAO inhibitors. These results demonstrated that the enzyme could be efficiently immobilized on the polymer-grafted magnetic nanoparticles and that the obtained enzyme reactor has great potential in screening enzyme inhibitors, further offering new insight into monitoring the relevant diseases.

  12. TetrakisHydroxymethylPhosphonium Sulfate (THPS), a new industrial biocide with low environmental toxicity

    SciTech Connect

    Downward, B.L.; Talbot, R.E.; Haack, T.K.

    1997-12-01

    THPS is a new biocide active designed for use in a variety of environmentally sensitive applications such as industrial cooling systems and oilfield situations. EPA registration has recently been achieved thus permitting, for the first time, the use of THPS based biocides in the US. This paper reviews the chemistry of THPS and reports a variety of case histories where THPS has successfully been used for the control of bacteria, algae and fungi in industrial cooling systems in Western Europe. An extensive data package, including field applications and laboratory studies, is available for THPS providing many exciting opportunities for this product in the US. Case studies are presented for a cooling system in a fuel reprocessing plant, a process water system for a textile plant, and cooling systems for a chemical plant and a confectionary site.

  13. Biocidal properties study of silver nanoparticles used for application in green housing

    NASA Astrophysics Data System (ADS)

    Küünal, Siim; Kutti, Sander; Rauwel, Protima; Guha, Mithu; Wragg, David; Rauwel, Erwan

    2016-07-01

    We report on the study of surfactant-free silver nanoparticles synthesized using non-hydrolytic sol-gel methods for applications in straw bale constructions. Micro-organism infestation in green constructions is of concern as their proliferation tends to induce health problems. We demonstrate the biocidal properties of these Ag nanoparticles and their efficacy against fungi. Outdoor tests with Ag nanoparticles have demonstrated the effective protection of straw against micro-organisms. Indoor tests using broth liquid are compared with a method of testing we recently developed where the possible nature of the biocidal properties of the silver nanoparticles are further probed. In contrast to the commonly reported results, this study shows that Ag nanoparticles synthesized using non-hydrolytic sol-gel methods have antifungal properties against common fungi in outdoor conditions which demonstrate high potential in related applications.

  14. New biocide with both N-chloramine and quaternary ammonium moieties exerts enhanced bactericidal activity.

    PubMed

    Li, Lingdong; Pu, Tianyun; Zhanel, George; Zhao, Nan; Ens, Werner; Liu, Song

    2012-09-01

    Considering the rise of antibiotic resistance, the development of new antibacterial agents with improved biocidal functions is urgently required. In this study, ionic 5,5-dimethylhydantoin (DMH) analogues containing either a quaternary ammonium moiety (2)-4) or a phosphonate functional group (5),-6), were designed and synthesized to investigate the possible enhancing effect of quaternary ammonium moieties on the antibacterial performance of N-chloramines. These ionic DMH analogues were converted to their N-chloramine counterparts either in free form or after being covalently immobilized on a polymer surface via the "click" chemistry method. In the subsequent antimicrobial assessment against multi-drug-resistant Escherichia coli (MDR-E. coli) and methicillin-resistant Staphylococcus aureus (MRSA), chlorinated 2 and 3, the cyclic N-chloramines with a structural cation, exhibited distinctly enhanced biocidal functions in solution and after immobilization on surfaces.

  15. Assessment of TBT and organic booster biocide contamination in seawater from coastal areas of South Korea.

    PubMed

    Kim, Nam Sook; Shim, Won Joon; Yim, Un Hyuk; Hong, Sang Hee; Ha, Sung Yong; Han, Gi Myung; Shin, Kyung-Hoon

    2014-01-15

    Seawater samples from major enclosed bays, fishing ports, and harbors of Korea were analyzed to determine levels of tributyltin (TBT) and booster biocides, which are antifouling agents used as alternatives to TBT. TBT levels were in the range of not detected (nd) to 23.9 ng Sn/L. Diuron and Irgarol 1051, at concentration ranges of 35-1360 ng/L and nd to 14 ng/L, respectively, were the most common alternative biocides present in seawater, with the highest concentrations detected in fishing ports. Hot spots were identified where TBT levels exceeded environmental quality targets even 6 years after a total ban on its use in Korea. Diuron exceeded the UK environmental quality standard (EQS) value in 73% of the fishing port samples, 64% of the major bays, and 42% of the harbors. Irgarol 1051 levels were marginally below the Dutch and UK EQS values at all sites.

  16. In Vitro Study of the Effect of Cationic Biocides on Bacterial Population Dynamics and Susceptibility▿

    PubMed Central

    Moore, Louise E.; Ledder, Ruth G.; Gilbert, Peter; McBain, Andrew J.

    2008-01-01

    Cationic biocides (CBs) are widely used in domestic and public hygiene and to control biofouling and microbial contamination in industry. The increased use of biocides has led to concern regarding possible reductions in biocide effectiveness. Domestic drain microcosms were stabilized for 5 months and then exposed to polyhexamethylene biguanide (PHMB) at 0.1, 0.2, and 0.4g liter−1 over 6 months and characterized throughout by differential culture, together with eubacterial-specific PCR-denaturing gradient gel electrophoresis. Additionally, MICs and minimal bactericidal concentrations (MBCs) for bacteria previously isolated from a domestic drain (n = 18) and the human skin (n = 13) were determined before, during, and after escalating, sublethal exposure (14 passages) to two quaternary ammonium compounds (QAC1 and QAC2), the bisbiguanide chlorhexidine (CHX), and PHMB. Exposure of the drain microcosm to PHMB did not decrease the total viable count although significant (P < 0.01) decreases in recovery were observed for the gram-positive cocci with associated clonal expansion of pseudomonads (from ca. 0.1% of the population to ca. 10%). This clonal expansion was also manifested as elevations in bacteria that could grow in the presence of PHMB, CHX, and QAC1. Decreases in susceptibility (greater than twofold) occurred for 10/31 of the test bacteria for QAC1, 14/31 for QAC2, 10/31 for CHX, and 7/31 for PHMB. Exposure of microcosms to PHMB targeted gram-positive species and caused the clonal expansion of pseudomonads. In terms of prolonged-sublethal passage on CBs, exposure to all the biocides tested resulted in susceptibility decreases for a proportion of test bacteria, but refractory clones were not generated. PMID:18515475

  17. Microencapsulation of Biocides for Reduced Copper, Long-life Antifouling Coatings

    DTIC Science & Technology

    2007-02-01

    together with Microtek produce microencapsulated DCOIT. Laboratory facilities equipped to produce from 100g – 500kg batches of microcapsules . These...FINAL REPORT Microencapsulation of Biocides for Reduced Copper, Long-life Antifouling Coatings ESTCP Project WP-0306 FEBRUARY 2007...octyl-4-isothi azolin-3-one (DCOIT) hns been microencapsulated nnd incorporated into collUllercially relevanl AF coatings. Re•ulls demon•ll’ntt long

  18. Assessment of the Performance of Iodine-Treated Biocidal Filters and Characterization of Virus Aerosols

    DTIC Science & Technology

    2009-07-01

    presumably due to the increased area of air/water interface. Aggregation results in a shielding effect and inert constituents yield an encasement effect ...protective effect of RH was observed. 1 ASSESSMENT OF THE PERFORMANCE OF IODINE-TREATED BIOCIDAL FILTERS AND CHARACTERIZATION OF VIRUS...electrets filter minimizes reaeroslization but also makes it difficult to discriminate the antimicrobial effect at the surface. The distribution of

  19. Activated soil filters for removal of biocides from contaminated run-off and waste-waters.

    PubMed

    Bester, Kai; Banzhaf, Stefan; Burkhardt, Michael; Janzen, Niklas; Niederstrasser, Bernd; Scheytt, Traugott

    2011-11-01

    Building facades can be equipped with biocides to prevent formation of algal, fungal and bacterial films. Thus run-off waters may contain these highly active compounds. In this study, the removal of several groups of biocides from contaminated waters by means of an activated soil filter was studied. A technical scale activated vertical soil filter (biofilter) with different layers (peat, sand and gravel), was planted with reed (Phragmites australis) and used to study the removal rates and fate of hydrophilic to moderate hydrophobic (log K(ow) 1.8-4.4) biocides and biocide metabolites such as: Terbutryn, Cybutryn (Irgarol® 1051), Descyclopropyl-Cybutryn (Cybutryn and Terbutryn metabolite), Isoproturon, Diuron, and its metabolite Diuron-desmonomethyl, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone and Iodocarbamate (Iodocarb). Three experiments were performed: the first one (36 d) under low flow conditions (61 L m(-2) d(-1)) reached removal rates between 82% and 100%. The second one was performed to study high flow conditions: During this experiment, water was added as a pulse to the filter system with a hydraulic load of 255 L m(-2) within 5 min (retention time <1 h). During this experiment the removal rates of the compounds decreased drastically. For five compounds (Cybutryn, Descyclopropyl-Cybutryn, Diuron, Isoproturon, and Iodocarb) the removal dropped temporarily below 60%, while it was always above 70% for the others (Terbutryn, Benzo-isothiazolinone, n-Octyl-isothiazolinone, Dichloro-n-octylisothiazolinone). However, this removal is a considerable improvement compared to direct discharge into surface waters or infiltration into soil without appropriate removal. In the last experiment the removal efficiencies of the different layers were studied. Though the peat layer was responsible for most of the removal, the sand and gravel layers also contributed significantly for some compounds. All compounds are rather removed by

  20. Antimicrobial properties and death-inducing mechanisms of saccharomycin, a biocide secreted by Saccharomyces cerevisiae.

    PubMed

    Branco, Patrícia; Francisco, Diana; Monteiro, Margarida; Almeida, Maria Gabriela; Caldeira, Jorge; Arneborg, Nils; Prista, Catarina; Albergaria, Helena

    2017-01-01

    We recently found that Saccharomyces cerevisiae (strain CCMI 885) secretes antimicrobial peptides (AMPs) derived from the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) that are active against various wine-related yeast and bacteria. Here, we show that several other S. cerevisiae strains also secrete natural biocide fractions during alcoholic fermentation, although at different levels, which correlates with the antagonistic effect exerted against non-Saccharomyces yeasts. We, therefore, term this biocide saccharomycin. The native AMPs were purified by gel-filtration chromatography and its antimicrobial activity was compared to that exhibited by chemically synthesized analogues (AMP1 and AMP2/3). Results show that the antimicrobial activity of the native AMPs is significantly higher than that of the synthetic analogues (AMP1 and AMP2/3), but a conjugated action of the two synthetic peptides is observed. Moreover, while the natural AMPs are active at pH 3.5, the synthetic peptides are not, since they are anionic and cannot dissolve at this acidic pH. These findings suggest that the molecular structure of the native biocide probably involves the formation of aggregates of several peptides that render them soluble under acidic conditions. The death mechanisms induced by the AMPs were also evaluated by means of epifluorescence microscopy-based methods. Sensitive yeast cells treated with the synthetic AMPs show cell membrane disruption, apoptotic molecular markers, and internalization of the AMPs. In conclusion, our work shows that saccharomycin is a natural biocide secreted by S. cerevisiae whose activity depends on the conjugated action of GAPDH-derived peptides. This study also reveals that S. cerevisiae secretes GAPDH-derived peptides as a strategy to combat other microbial species during alcoholic fermentations.

  1. Chronic Exposure to Static Magnetic Fields from Magnetic Resonance Imaging Devices Deserves Screening for Osteoporosis and Vitamin D Levels: A Rat Model.

    PubMed

    Gungor, Harun R; Akkaya, Semih; Ok, Nusret; Yorukoglu, Aygun; Yorukoglu, Cagdas; Kiter, Esat; Oguz, Emin O; Keskin, Nazan; Mete, Gulcin A

    2015-07-30

    Technicians often receive chronic magnetic exposures from magnetic resonance imaging (MRI) devices, mainly due to static magnetic fields (SMFs). Here, we ascertain the biological effects of chronic exposure to SMFs from MRI devices on the bone quality using rats exposed to SMFs in MRI examining rooms. Eighteen Wistar albino male rats were randomly assigned to SMF exposure (A), sham (B), and control (C) groups. Group A rats were positioned within 50 centimeters of the bore of the magnet of 1.5 T MRI machine during the nighttime for 8 weeks. We collected blood samples for biochemical analysis, and bone tissue samples for electron microscopic and histological analysis. The mean vitamin D level in Group A was lower than in the other groups (p = 0.002). The mean cortical thickness, the mean trabecular wall thickness, and number of trabeculae per 1 mm2 were significantly lower in Group A (p = 0.003). TUNEL assay revealed that apoptosis of osteocytes were significantly greater in Group A than the other groups (p = 0.005). The effect of SMFs in chronic exposure is related to movement within the magnetic field that induces low-frequency fields within the tissues. These fields can exceed the exposure limits necessary to deteriorate bone microstructure and vitamin D metabolism.

  2. A novel method for comparison of biocidal properties of nanomaterials to bacteria, yeasts and algae.

    PubMed

    Suppi, Sandra; Kasemets, Kaja; Ivask, Angela; Künnis-Beres, Kai; Sihtmäe, Mariliis; Kurvet, Imbi; Aruoja, Villem; Kahru, Anne

    2015-04-09

    Toxicity testing of nanomaterials (NMs) is experimentally challenging because NMs may interfere with test environment and assay components. In this work we propose a simple and reliable method--a 'spot test' to compare biocidal potency of NMs to unicellular microorganisms such as bacteria, yeasts and algae. The assay is straightforward: cells are incubated in deionized water suspensions of NMs for up to 24h and then pipetted as a 'spot' on agarized medium. Altogether seven bacterial strains, yeast and a microalga were tested. CuO, TiO2 and two different Ag NPs, multi-wall C-nanotubes (MWCNTs), AgNO3, CuSO4, 3,5-dichlorophenol, triclosan and H2O2 were analyzed. The biocidal potency of tested substances ranged from 0.1mg/L to >1000 mg/L; whereas, the least potent NMs toward all test species were TiO2 NPs and MWCNTs and most potent Ag and CuO NPs. Based on the similar toxicity pattern of the tested chemicals on the nine unicellular organisms in deionized water we conclude that toxicity mechanism of biocidal chemicals seems to be similar, whatever the organism (bacteria, yeast, alga). Therefore, when the organisms are not 'protected' by their environment that usually includes various organic and inorganic supplements their tolerance to toxicants is chemical- rather than organism-dependent.

  3. A multiproxy approach to evaluate biocidal treatments on biodeteriorated majolica glazed tiles.

    PubMed

    Coutinho, M L; Miller, A Z; Martin-Sanchez, P M; Mirão, J; Gomez-Bolea, A; Machado-Moreira, B; Cerqueira-Alves, L; Jurado, V; Saiz-Jimenez, C; Lima, A; Phillips, A J L; Pina, F; Macedo, M F

    2016-12-01

    The Fishing House located on the grounds of the Marquis of Pombal Palace, Oeiras, Portugal, was built in the 18th century. During this epoch, Portuguese gardens, such as the one surrounding the Fishing House, were commonly ornamented with glazed wall tile claddings. Currently, some of these outdoor tile panels are covered with dark colored biofilms, contributing to undesirable aesthetic changes and eventually inducing chemical and physical damage to the tile surfaces. Phylogenetic analyses revealed that the investigated biofilms are mainly composed of green algae, cyanobacteria and dematiaceous fungi. With the aim of mitigating biodeterioration, four different biocides (TiO2 nanoparticles, Biotin(®) T, Preventol(®) RI 80 and Albilex Biostat(®) ) were applied in situ to the glazed wall tiles. Their efficacy was monitored by visual examination, epifluorescence microscopy and DNA-based analysis. Significant changes in the microbial community composition were observed 4 months after treatment with Preventol(®) RI 80 and Biotin(®) T. Although the original community was inactivated after these treatments, an early stage of re-colonization was detected 6 months after the biocide application. TiO2 nanoparticles showed promising results due to their self-cleaning effect, causing the detachment of the biofilm from the tile surface, which remained clean 6 and even 24 months after biocide application. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Leaching of biocides from façades under natural weather conditions.

    PubMed

    Burkhardt, M; Zuleeg, S; Vonbank, R; Bester, K; Carmeliet, J; Boller, M; Wangler, T

    2012-05-15

    Biocides are included in organic building façade coatings as protection against biological attack by algae and fungi but have the potential to enter the environment via leaching into runoff from wind driven rain. The following field study correlates wind driven rain to runoff and measured the release of several commonly used organic biocides (terbutryn, Irgarol 1051, diuron, isoproturon, OIT, DCOIT) in organic façade coatings from four coating systems. During one year of exposure of a west oriented model house façade in the Zurich, Switzerland area, an average of 62.7 L/m(2), or 6.3% of annual precipitation came off the four façade panels installed as runoff. The ISO method for calculating wind driven rain loads is adapted to predict runoff and can be used in the calculation of emissions in the field. Biocide concentrations tend to be higher in the early lifetime of the coatings and then reach fairly consistent levels later, generally ranging on the order of mg/L or hundreds of μg/L. On the basis of the amount remaining in the film after exposure, the occurrence of transformation products, and the calculated amounts in the leachate, degradation plays a significant role in the overall mass balance.

  5. Online magnetic bead based dynamic protein affinity selection coupled to LC-MS for the screening of acetylcholine binding protein ligands.

    PubMed

    Pochet, Lionel; Heus, Ferry; Jonker, Niels; Lingeman, Henk; Smit, August B; Niessen, Wilfried M A; Kool, Jeroen

    2011-06-15

    A magnetic beads based affinity-selection methodology towards the screening of acetylcholine binding protein (AChBP) binders in mixtures and pure compound libraries was developed. The methodology works as follows: after in solution incubation of His-tagged AChBP with potential ligands, and subsequent addition of cobalt (II)-coated paramagnetic beads, the formed bead-AChBP-ligand complexes are fetched out of solution by injection and trapping in LC tubing with an external adjustable magnet. Non binders are then washed to the waste followed by elution of ligands to a SPE cartridge by flushing with denaturing solution. Finally, SPE-LC-MS analysis is performed to identify the ligands. The advantage of the current methodology is the in solution incubation followed by immobilized AChBP ligand trapping and the capability of using the magnetic beads system as mobile/online transportable affinity SPE material. The system was optimized and then successfully demonstrated for the identification of AChBP ligands injected as pure compounds and for the fishing of ligands in mixtures. The results obtained with AChBP as target protein demonstrated reliable discrimination between binders with pK(i) values ranging from at least 6.26 to 8.46 and non-binders.

  6. Resistance to Biocides in Listeria monocytogenes Collected in Meat-Processing Environments

    PubMed Central

    Conficoni, Daniele; Losasso, Carmen; Cortini, Enzo; Di Cesare, Andrea; Cibin, Veronica; Giaccone, Valerio; Corno, Gianluca; Ricci, Antonia

    2016-01-01

    The emergence of microorganisms exerting resistance to biocides is a challenge to meat-processing environments. Bacteria can be intrinsically resistant to biocides but resistance can also be acquired by adaptation to their sub-lethal concentrations. Moreover, the presence of biocide resistance determinants, which is closely linked to antibiotic resistance determinants, could lead to co-selection during disinfection practices along the food chain, and select cross-resistant foodborne pathogens. The purpose of this work was to test the resistance of wild strains of Listeria monocytogenes, isolated from pork meat processing plants, toward benzalkonium chloride (BC), used as proxy of quaternary ammonium compounds. Furthermore, the expression of two non-specific efflux pumps genes (lde and mdrL) under biocide exposure was evaluated. L. monocytogenes were isolated from five processing plants located in the Veneto region (northeast of Italy) before and after cleaning and disinfection (C&D) procedures. A total of 45 strains were collected: 36 strains before and nine after the C&D procedures. Collected strains were typed according to MLST and ERIC profiles. Strains sampled in the same site, isolated before, and after the C&D procedures and displaying the same MLST and ERIC profiles were tested for their sensitivity to different concentrations of BC, in a time course assay. The expression of non-specific efflux pumps was evaluated at each time point by qPCR using tufA gene as housekeeping. A differential expression of the two investigated genes was observed: lde was found to be more expressed by the strains isolated before C&D procedures while its expression was dose-dependent in the case of the post C&D procedures strain. On the contrary, the expression of mdrL was inhibited under low biocidal stress (10 ppm BC) and enhanced in the presence of high stress (100 ppm BC). These findings suggests a possible role for C&D procedures to select L. monocytogenes persisters, pointing

  7. Oligonucleotide Based Magnetic Bead Capture of Onchocerca volvulus DNA for PCR Pool Screening of Vector Black Flies

    PubMed Central

    Gopal, Hemavathi; Hassan, Hassan K.; Rodríguez-Pérez, Mario A.; Toé, Laurent D.; Lustigman, Sara; Unnasch, Thomas R.

    2012-01-01

    Background Entomological surveys of Simulium vectors are an important component in the criteria used to determine if Onchocerca volvulus transmission has been interrupted and if focal elimination of the parasite has been achieved. However, because infection in the vector population is quite rare in areas where control has succeeded, large numbers of flies need to be examined to certify transmission interruption. Currently, this is accomplished through PCR pool screening of large numbers of flies. The efficiency of this process is limited by the size of the pools that may be screened, which is in turn determined by the constraints imposed by the biochemistry of the assay. The current method of DNA purification from pools of vector black flies relies upon silica adsorption. This method can be applied to screen pools containing a maximum of 50 individuals (from the Latin American vectors) or 100 individuals (from the African vectors). Methodology/Principal Findings We have evaluated an alternative method of DNA purification for pool screening of black flies which relies upon oligonucleotide capture of Onchocerca volvulus genomic DNA from homogenates prepared from pools of Latin American and African vectors. The oligonucleotide capture assay was shown to reliably detect one O. volvulus infective larva in pools containing 200 African or Latin American flies, representing a two-four fold improvement over the conventional assay. The capture assay requires an equivalent amount of technical time to conduct as the conventional assay, resulting in a two-four fold reduction in labor costs per insect assayed and reduces reagent costs to $3.81 per pool of 200 flies, or less than $0.02 per insect assayed. Conclusions/Significance The oligonucleotide capture assay represents a substantial improvement in the procedure used to detect parasite prevalence in the vector population, a major metric employed in the process of certifying the elimination of onchocerciasis. PMID:22724041

  8. Comparison of the efficacy of natural-based and synthetic biocides to disinfect silicone and stainless steel surfaces.

    PubMed

    Gomes, I B; Malheiro, J; Mergulhão, F; Maillard, J-Y; Simões, M

    2016-06-01

    New biocidal solutions are needed to combat effectively the evolution of microbes developing antibiotic resistance while having a low or no environmental toxicity impact. This work aims to assess the efficacy of commonly used biocides and natural-based compounds on the disinfection of silicone and stainless steel (SS) surfaces seeded with differentStaphylococcus aureusstrains. Minimum inhibitory concentration was determined for synthetic (benzalkonium chloride-BAC, glutaraldehyde-GTA,ortho-phthalaldehyde-OPA and peracetic acid-PAA) and natural-based (cuminaldehyde-CUM), eugenol-EUG and indole-3-carbinol-I3C) biocides by the microdilution method. The efficacy of selected biocides at MIC, 10 × MIC and 5500 mg/L (representative in-use concentration) on the disinfection of sessileS. aureuson silicone and SS was assessed by viable counting. Silicone surfaces were harder to disinfect than SS. GTA, OPA and PAA yielded complete CFU reduction of sessile cells for all test concentrations as well as BAC at 10 × MIC and 5500 mg/L. CUM was the least efficient compound. EUG was efficient for SS disinfection, regardless of strains and concentrations tested. I3C at 10 × MIC and 5500 mg/L was able to cause total CFU reduction of silicone and SS deposited bacteria. Although not so efficient as synthetic compounds, the natural-based biocides are promising to be used in disinfectant formulations, particularly I3C and EUG.

  9. Utility of SPM8 plus DARTEL (VSRAD) combined with magnetic resonance spectroscopy as adjunct techniques for screening and predicting dementia due to Alzheimer's disease in clinical practice.

    PubMed

    Waragai, Masaaki; Hata, Saori; Suzuki, Toshiharu; Ishii, Ryotaro; Fujii, Chihiro; Tokuda, Takahiko; Arai, Hiroyuki; Ohrui, Takashi; Higuchi, Susumu; Yoshida, Madoka; Igarashi, Kazuei; Moriya, Masaru; Iwai, Naomichi; Uemura, Kenichi

    2014-01-01

    We validated the utility of SPM8 plus DARTEL (VSRAD) combined with magnetic resonance spectroscopy (1H MRS) as an adjunct screening technique for dementia due to Alzheimer's disease (AD). We examined the posterior cingulate gyri of 228 subjects using VSRAD and 1H MRS in addition to conventional cerebrospinal fluid biomarkers at baseline. At the 3-year follow-up, the 228 subject were classified as follows: 93 healthy subjects, 42 MCI-non-converters (MCI-NC), 25 MCI-converters to AD (MCI-C), 44 AD, 8 dementia with Lewy bodies (DLB), 5 normal pressure hydrocephalus, and 11 patients with other neurological diseases. Our results demonstrated that subjects with increased medial temporal atrophy (MTA) severity on VSRAD, increased Cho/Cr, MI/Cr ratio, and decreased NAA/Cr and NAA/MI ratio on 1H MRS at baseline were at risk of dementia due to AD. Receiver operating characteristic analysis showed that severity of MTA and the NAA/MI ratio distinguished patients with AD and MCI-C from controls. Furthermore, the 118 subjects without dementia and MTA showing only a decreased NAA/MI ratio at baseline developed to MCI-C, AD, and DLB 3 years later. 1H MRS detected biochemical abnormalities preceding brain atrophy and cognitive decline. VSRAD combined with 1H MRS may be routinely applied to screen for MCI/AD and prodromal AD in clinical practice.

  10. Screening of inhibitors of glycogen synthase kinase-3β from traditional Chinese medicines using enzyme-immobilized magnetic beads combined with high-performance liquid chromatography.

    PubMed

    Li, Yunfang; Xu, Jia; Chen, Yu; Mei, Zhinan; Xiao, Yuxiu

    2015-12-18

    Glycogen synthase kinase-3β (GSK-3β) was immobilized on magnetic beads (MBs) by affinity method for the first time. The enzyme-immobilized MBs were coupled with high-performance liquid chromatography-ultraviolet (HPLC-UV) technique to establish a cost-effective and reliable method for screening of inhibitors of GSK-3β. A peptide substrate of GSK-3β containing a tyrosine residue was employed since it can be sensitively detected by UV detector at 214nm. The substrate and its phosphorylated product were separated by baseline within 10min. The enzyme activity was determined by the quantification of peak area of the product. Parameters including enzyme immobilization, enzyme reaction and the performance of immobilized-enzyme were investigated. The immobilized enzyme can be reused for 10 times and remain stable for 4 days at 4°C. The inhibitory activities of extracts of 15 traditional Chinese medicines (TCMs) were screened. As a result, three of them including Euonymus fortunei, Amygdalus communis and Garcinia xanthochymus were found possessing high inhibitory activities (inhibition rate >90%). From G. xanthochymus, a new inhibitor of GSK-3β, fukugetin, was discovered with an IC50 value of 3.18±0.07μM. Enzyme kinetics and molecular docking experiments further revealed the inhibitory mechanism, indicating fukugetin was a non-ATP competitive inhibitor interacting with the phosphate recognizing substrate binding site of GSK-3β.

  11. Newborn Screening

    MedlinePlus

    ... Activities Importance of Newborn Screening Newborn Screening and Molecular Biology Branch Pulse Oximetry Screening for CCHDs Sickle Cell Disease Laboratory SCID Quality Assurance Training and Resources ...

  12. Degradation of a commercial textile biocide with advanced oxidation processes and ozone.

    PubMed

    Arslan-Alaton, Idil

    2007-01-01

    The occurrence of significant amounts of biocidal finishing agents in the environment as a consequence of intensive textile finishing activities has become a subject of major public health concern and scientific interest only recently. In the present study, the treatment efficiency of selected, well-known advanced oxidation processes (Fenton, Photo-Fenton, TiO(2)/UV-A, TiO(2)/UV-A/H(2)O(2)) and ozone was compared for the degradation and detoxification of a commercial textile biocide formulation containing a 2,4,4'-trichloro-2'-hydroxydiphenyl ether as the active ingredient. The aqueous biocide solution was prepared to mimic typical effluent originating from the antimicrobial finishing operation (BOD(5,o) < or =5 mg/L; COD(o)=200 mg/L; DOC(o) (dissolved organic carbon)=58 mg/L; AOX(o) (adsorbable organic halogens)=48 mg/L; LC(50,o) (lethal concentration causing 50% death or immobilization in Daphnia magna)=8% v/v). Ozonation experiments were conducted at different ozone doses (500-900 mg/h) and initial pH (7-12) to assess the effect of ozonation on degradation (COD, DOC removal), dearomatization (UV(280) and UV(254) abatement), dechlorination (AOX removal) and detoxification (changes in LC(50)). For the Fenton experiments, the effect of varying ferrous iron catalyst concentrations and UV-A light irradiation (the Photo-Fenton process) was examined. In the heterogenous photocatalytic experiments, Degussa P25-type TiO(2) was used as the catalyst and the effect of reaction pH (3, 7 and 12) and H(2)O(2) addition on the photocatalytic treatment efficiency was examined. Although in the photochemical (i.e. Photo-Fenton, TiO(2)/UV-A and TiO(2)/UV-A/H(2)O(2)) experiments appreciably higher COD and DOC removal efficiencies were obtained, ozonation appeared to be equally effective to achieve dearomatization (UV(280) abatement) at all studied reaction pH. During ozonation of the textile biocide effluent, AOX abatement proceeded significantly faster than dearomatization and was

  13. Significance of urban and agricultural land use for biocide and pesticide dynamics in surface waters.

    PubMed

    Wittmer, I K; Bader, H-P; Scheidegger, R; Singer, H; Lück, A; Hanke, I; Carlsson, C; Stamm, C

    2010-05-01

    Biocides and pesticides are designed to control the occurrence of unwanted organisms. From their point of application, these substances can be mobilized and transported to surface waters posing a threat to the aquatic environment. Historically, agricultural pesticides have received substantially more attention than biocidal compounds from urban use, despite being used in similar quantities. This study aims at improving our understanding of the influence of mixed urban and agricultural land use on the overall concentration dynamics of biocides and pesticides during rain events throughout the year. A comprehensive field study was conducted in a catchment within the Swiss plateau (25 km(2)). Four surface water sampling sites represented varying combinations of urban and agricultural sources. Additionally, the urban drainage system was studied by sampling the only wastewater treatment plant (WWTP) in the catchment, a combined sewer overflow (CSO), and a storm sewer (SS). High temporal resolution sampling was carried out during rain events from March to November 2007. The results, based on more than 600 samples analyzed for 23 substances, revealed distinct and complex concentration patterns for different compounds and sources. Five types of concentration patterns can be distinguished: a) compounds that showed elevated background concentrations throughout the year (e.g. diazinon >50 ng L(-1)), indicating a constant household source; b) compounds that showed elevated concentrations driven by rain events throughout the year (e.g. diuron 100-300 ng L(-1)), indicating a constant urban outdoor source such as facades; c) compounds with seasonal peak concentrations driven by rain events from urban and agricultural areas (e.g. mecoprop 1600 ng L(-1) and atrazine 2500 ng L(-1) respectively); d) compounds that showed unpredictably sharp peaks (e.g. atrazine 10,000 ng L(-1), diazinon 2500 ng L(-1)), which were most probably due to improper handling or even disposal of products; and

  14. Durable and rechargeable biocidal polypropylene polymers and fibers prepared by using reactive extrusion.

    PubMed

    Badrossamay, Mohammad Reza; Sun, Gang

    2009-04-01

    Incorporation of N-halamine precursor onto polypropylene was explored by using a reactive extrusion process. Several cyclic and acyclic halamine precursors were grafted onto polypropylene backbone through a melt free radical graft copolymerization. The structures and morphology of the grafted polymer were characterized with FTIR, and scanning electron microscope. Thermal properties of the polymers were evaluated by differential scanning calorimetry. The halogenated products of the corresponding grafted samples exhibited potent antimicrobial properties against Escherichia coli, and the antimicrobial properties were durable and regenerable. The relationship between effective surface contact and biocidal efficacy are further discussed.

  15. Impact of biocide treatments on the bacterial communities of the Lascaux Cave.

    PubMed

    Bastian, Fabiola; Alabouvette, Claude; Jurado, Valme; Saiz-Jimenez, Cesareo

    2009-07-01

    The Lascaux Cave contains a remarkable set of paintings from the Upper Palaeolithic. Shortly after discovery in 1940, the cave was modified for public viewing and, in 2001, was invaded by a Fusarium solani species complex. Benzalkonium chloride was used from 2001 to 2004 to eliminate the fungal outbreak. In this study, we carried out a sampling in most of the cave halls and galleries. Sequence analysis and isolation methods detected that the most abundant genera of bacteria were Ralstonia and Pseudomonas. We suggest that, as a result of years of benzalkonium chloride treatments, the indigenous microbial community has been replaced by microbial populations selected by biocide application.

  16. Impact of biocide treatments on the bacterial communities of the Lascaux Cave

    NASA Astrophysics Data System (ADS)

    Bastian, Fabiola; Alabouvette, Claude; Jurado, Valme; Saiz-Jimenez, Cesareo

    2009-07-01

    The Lascaux Cave contains a remarkable set of paintings from the Upper Palaeolithic. Shortly after discovery in 1940, the cave was modified for public viewing and, in 2001, was invaded by a Fusarium solani species complex. Benzalkonium chloride was used from 2001 to 2004 to eliminate the fungal outbreak. In this study, we carried out a sampling in most of the cave halls and galleries. Sequence analysis and isolation methods detected that the most abundant genera of bacteria were Ralstonia and Pseudomonas. We suggest that, as a result of years of benzalkonium chloride treatments, the indigenous microbial community has been replaced by microbial populations selected by biocide application.

  17. Biocidal efficacy, biofilm-controlling function, and controlled release effect of chloromelamine-based bioresponsive fibrous materials

    PubMed Central

    Chen, Zhaobin; Luo, Jie; Sun, Yuyu

    2007-01-01

    In this study, 2-amino-4-chloro-6-hydroxy-s-triazine (ACHT) was synthesized through controlled hydrolysis of 2-amino-4,6-dichloro-s-triazine (ADCT). A simple paddry-cure approach was employed to immobilize ACHT onto cellulosic fibrous materials. After treatment with diluted chlorine bleach, the covalently bound ACHT moieties were transformed into chloromelamines. The structures of the samples were fully characterized with NMR, UV/VIS, DSC, TG, iodometric titration and elemental analyses. The chloromelamine-based fibrous materials provided potent, durable, and rechargeable biocidal functions against bacteria (including multi-drug resistant species), yeasts, viruses, and bacterial spores. SEM studies demonstrated that the new fibrous materials could effectively prevent the formation of biofilms, and controlled release investigations in vitro suggested that the biocidal activities were bioresponsive. Biocidal mechanisms of the chloromelamine-based fibrous materials were further discussed. PMID:17184837

  18. Probabilistic risk assessment of common booster biocides in surface waters of the harbours of Gran Canaria (Spain).

    PubMed

    Sánchez-Rodríguez, Alvaro; Sosa-Ferrera, Zoraida; Santana-del Pino, Angelo; Santana-Rodríguez, José Juan

    2011-05-01

    The presence of booster biocides in the aquatic environment has been associated with a risk to non-target species due to their proven toxicity. The aim of the present study was to determine the spatial and temporal distribution of common booster biocides in different harbours of the island of Gran Canaria (Spain) and evaluate, by means of a probabilistic risk assessment (PRA), the ecological risk posed by these compounds. With these objectives, a monitoring campaign was conducted between January 2008 and May 2009, collecting a total of 182 seawater samples. Four common booster biocides (TCMTB, diuron, Irgarol 1051 and dichlofluanid) were monitored. Diuron levels ranged between 2.3 and 203 ng/L and Irgarol 1051 between 2.4 and 146.5 ng/L. The ecological risk associated with these levels was always low, however, with probabilities of exceeding the 10th percentile of autotroph toxicity below 3.5%.

  19. MAGNETS

    DOEpatents

    Hofacker, H.B.

    1958-09-23

    This patent relates to nmgnets used in a calutron and more particularly to means fur clamping an assembly of magnet coils and coil spacers into tightly assembled relation in a fluid-tight vessel. The magnet comprises windings made up of an assembly of alternate pan-cake type coils and spacers disposed in a fluid-tight vessel. At one end of the tank a plurality of clamping strips are held firmly against the assembly by adjustable bolts extending through the adjacent wall. The foregoing arrangement permits taking up any looseness which may develop in the assembly of coils and spacers.

  20. A mechanism for inducing climatic variations through the stratosphere - Screening of cosmic rays by solar and terrestrial magnetic fields

    NASA Technical Reports Server (NTRS)

    Chamberlain, J. W.

    1977-01-01

    The ability of heliomagnetic and geomagnetic fields to bring about climatic variations of long period is examined theoretically. A chemical relationship between low-energy cosmic rays and ozone balance in the stratosphere is sought as a crucial clue to historical changes in earth climate. A perturbation analysis is developed to arrive at zone depletion and reduction of stratospheric solar heating resulting from increased NOx concentration; temperature feedback and opacity feedback are allowed for. Modulation of galactic cosmic-radiation fluxes and ozone destruction in the stratosphere, colder surface temperatures associated with reduced magnetic shielding, and redistribution with height of total ozone decrease are explored.

  1. Suitability of small environmental chambers to test the emission of biocides from treated materials into the air

    NASA Astrophysics Data System (ADS)

    Horn, Wolfgang; Jann, Oliver; Wilke, Olaf

    Biocides are used to protect materials that might be damaged by fungal, microbial or insect activity. The aim of this study is to develop a method for the measurement of these organic compounds, which generally have low or moderate vapor pressures. The biocides considered in this study are permethrin, dichlofluanid, tolylfluanid, iodpropinylbutylcarbamat, octylisothiazolinone, tebuconazole and propiconazole. The emission from two commercial products (plastic foil, wool carpet) containing biocides and of seven types of biocidal formulations applied to wood or clay tiles were investigated in 20-l glass emission test chambers. Each chamber test was performed over a period of 100-200 days, and one investigation was conducted over several years. Compared to volatile organic compounds, low-volatility compounds show totally different emission curves in chamber tests; maximal emission values may be reached in days or weeks. A period of 3 months is sometimes necessary for the determination of area-specific emission rates (SER a's). The SER a's (μg m -2 h -1) from biocide-containing products were determined for permethrin (0.006), propiconazole (0.3), dichlofluanid (2.0), tolylfluanid (1.0), octylisothiazolinone (2.5) and iodpropinylbutylcarbamat (2). In most cases, the SER a stayed at its maximum value or declined slowly over the test period. Additionally, a chamber test begun in 1994 with a piece of wood treated with a typical mixture of biocides dissolved in a technical solvent was continued. SER a's (μg m -2 h -1) for dichlofluanid (0.20), tebuconazole (0.49) and permethrin (0.08) remained detectable after the period of nearly 9 years during which the sample remained continuously in the chamber. This test proved the very slow decrease of emission of low-volatility compounds like permethrin and tebuconazole.

  2. Effects of Antifouling Biocides on Molecular and Biochemical Defense System in the Gill of the Pacific Oyster Crassostrea gigas

    PubMed Central

    Park, Mi Seon; Kim, Young Dae; Kim, Bo-Mi; Kim, Youn-Jung; Kim, Jang Kyun; Rhee, Jae-Sung

    2016-01-01

    Antifouling biocides such as organotin compounds and their alternatives are potent toxicants in marine ecosystems. In this study, we employed several molecular and biochemical response systems of the Pacific oyster Crassostrea gigas to understand a potential mode of action of antifouling biocides (i.e. tributyltin (TBT), diuron and irgarol) after exposure to different concentrations (0.01, 0.1, and 1 μg L-1) for 96 h. As a result, all the three antifouling biocides strongly induced the antioxidant defense system. TBT reduced both enzymatic activity and mRNA expression of Na+/K+-ATPase and acetylcholinesterase (AChE). Lower levels of both Na+/K+-ATPase activity and AChE mRNA expression were observed in the diuron-exposed oysters compared to the control, while the irgarol treatment reduced only the transcriptional expression of AChE gene. We also analyzed transcript profile of heat shock protein (Hsp) superfamily in same experimental conditions. All antifouling biocides tested in this study significantly modulated mRNA expression of Hsp superfamily with strong induction of Hsp70 family. Taken together, overall results indicate that representative organotin TBT and alternatives have potential hazardous effects on the gill of C. gigas within relatively short time period. Our results also suggest that analyzing a series of molecular and biochemical parameters can be a way of understanding and uncovering the mode of action of emerging antifouling biocides. In particular, it was revealed that Pacific oysters have different sensitivities depend on the antifouling biocides. PMID:28006823

  3. Biocide and antibiotic susceptibility of Salmonella isolates obtained before and after cleaning at six Danish pig slaughterhouses.

    PubMed

    Gantzhorn, Mette Rørbæk; Pedersen, Karl; Olsen, John Elmerdahl; Thomsen, Line Elnif

    2014-07-02

    Salmonella sp. continues to be one of the most important foodborne pathogens. Control measures in terms of cleaning and disinfection on food production plants are very important for limiting the risk of contaminated food products to reach the consumer. In the last decade concern has arisen that bacteria exposed to disinfectants can develop resistance toward disinfectants and can have a higher risk of developing antibiotic resistance. The objectives of this study were to examine the prevalence of biocide resistant Salmonella sp. in Danish pig slaughterhouses, to evaluate if there was a correlation between susceptibilities to biocides and antibiotics, and to examine if cleaning and disinfection select isolates with changed susceptibility toward biocides or antibiotics. Salmonella sp. was isolated from the environment in Danish pig slaughterhouses before and after cleaning and disinfection. The susceptibility toward three different biocides, triclosan and two commercial disinfection products: Desinfect Maxi, a quaternary ammonium compound, and Incimaxx DES, an acetic compound, was determined. We found no resistance toward the biocides tested, but we did find that isolates obtained after cleaning had higher minimum inhibitory concentration (MIC) values toward one of the disinfectants (Incimaxx DES) compared to isolates obtained before cleaning and disinfection. This could indicate selection of strains that are more tolerant, due to the cleaning and disinfection. Furthermore, we found that there was a weak statistical correlation between MICs toward the biocides and some antibiotics, but no difference in log(MIC)s toward antibiotics between isolates obtained before and after cleaning, nor did we find any difference in the number of resistances of isolates obtained before and after cleaning and disinfection.

  4. A mechanism for inducing climatic variations through ozone destruction: Screening of galactic cosmic rays by solar and terrestrial magnetic fields

    NASA Technical Reports Server (NTRS)

    Chamberlain, J. W.

    1976-01-01

    A perturbation analysis, allowing for temperature and opacity feedbacks, is developed to calculate depletions in the O3 abundance and reductions of stratospheric solar heating that result from increases in NOx concentration. A pair of perturbation coefficients give the reduction in O3 and temperature through the stratosphere for a specified NOx increase. This type of analysis illustrates the tendency for various levels to self-heal when a perturbation occurs. Physical arguments indicate that the expected sign of the climatic effect is correct, with colder surface temperatures produced by reduced magnetic shielding. In addition, four qualitative reasons are suggested for thinking that significant ozone reductions by cosmic ray influxes will lead to an increased terrestrial albedo from stratospheric condensation. In this view, long-term (approximately 10,000 years) climatic changes have resulted from secular geomagnetic variations while shorter (approximately 100 years) excursions are related to changes in solar activity.

  5. Surface-attached cells, biofilms and biocide susceptibility: implications for hospital cleaning and disinfection.

    PubMed

    Otter, J A; Vickery, K; Walker, J T; deLancey Pulcini, E; Stoodley, P; Goldenberg, S D; Salkeld, J A G; Chewins, J; Yezli, S; Edgeworth, J D

    2015-01-01

    Microbes tend to attach to available surfaces and readily form biofilms, which is problematic in healthcare settings. Biofilms are traditionally associated with wet or damp surfaces such as indwelling medical devices and tubing on medical equipment. However, microbes can survive for extended periods in a desiccated state on dry hospital surfaces, and biofilms have recently been discovered on dry hospital surfaces. Microbes attached to surfaces and in biofilms are less susceptible to biocides, antibiotics and physical stress. Thus, surface attachment and/or biofilm formation may explain how vegetative bacteria can survive on surfaces for weeks to months (or more), interfere with attempts to recover microbes through environmental sampling, and provide a mixed bacterial population for the horizontal transfer of resistance genes. The capacity of existing detergent formulations and disinfectants to disrupt biofilms may have an important and previously unrecognized role in determining their effectiveness in the field, which should be reflected in testing standards. There is a need for further research to elucidate the nature and physiology of microbes on dry hospital surfaces, specifically the prevalence and composition of biofilms. This will inform new approaches to hospital cleaning and disinfection, including novel surfaces that reduce microbial attachment and improve microbial detachment, and methods to augment the activity of biocides against surface-attached microbes such as bacteriophages and antimicrobial peptides. Future strategies to address environmental contamination on hospital surfaces should consider the presence of microbes attached to surfaces, including biofilms.

  6. Green biocides, a promising technology: current and future applications to industry and industrial processes.

    PubMed

    Ashraf, Muhammad Aqeel; Ullah, Saleem; Ahmad, Irshad; Qureshi, Ahmad Kaleem; Balkhair, Khaled S; Abdur Rehman, Muhammad

    2014-02-01

    The study of biofilms has skyrocketed in recent years due to increased awareness of the pervasiveness and impact of biofilms. It costs the USA literally billions of dollars every year in energy losses, equipment damage, product contamination and medical infections. But biofilms also offer huge potential for cleaning up hazardous waste sites, filtering municipal and industrial water and wastewater, and forming biobarriers to protect soil and groundwater from contamination. The complexity of biofilm activity and behavior requires research contributions from many disciplines such as biochemistry, engineering, mathematics and microbiology. The aim of this review is to provide a comprehensive analysis of emerging novel antimicrobial techniques, including those using myriad organic and inorganic products as well as genetic engineering techniques, the use of coordination complex molecules, composite materials and antimicrobial peptides and the use of lasers as such or their modified use in combination treatments. This review also addresses advanced and recent modifications, including methodological changes, and biocide efficacy enhancing strategies. This review will provide future planners of biofilm control technologies with a broad understanding and perspective on the use of biocides in the field of green developments for a sustainable future.

  7. Climate as the most important factor determining anti-fungal biocide performance in paint films.

    PubMed

    Shirakawa, Márcia Aiko; Tavares, Roberta Gonçalves; Gaylarde, Christine Claire; Taqueda, Maria Elena Santos; Loh, Kai; John, Vanderley Moacyr

    2010-11-01

    The effect of Pigment Volume Content (PVC) on fungal growth on acrylic paint formulations with and without biocide, exposed to weathering in three different climatic regions in Brazil for four years, was studied. Latex paints, with PVC of 30%, 35% and 50%, were applied to autoclaved aerated concrete blocks pre-covered with acrylic sealer and acrylic plaster. They were exposed to equatorial, tropical and temperate climates in north, south-east, and south Brazil. Cladosporium was the most abundant fungal genus detected in the biofilm on the surfaces of all paint formulations at all sites after four years. Heaviest fungal colonization occurred in the tropical south-east and lightest in the temperate south of the country, but more phototrophs, principally cyanobacteria, were detected in the equatorial region. PVC and presence of biocides were shown to be of less importance than environmental conditions (irradiance, humidity and temperature) for biofilm formation and consequent discolouration. These results have important implications for testing of paint formulations.

  8. EU Regulation of Nanobiocides: Challenges in Implementing the Biocidal Product Regulation (BPR)

    PubMed Central

    Brinch, Anna; Hansen, Steffen Foss; Hartmann, Nanna B.; Baun, Anders

    2016-01-01

    The Biocidal Products Regulation (BPR) contains several provisions for nanomaterials (NMs) and is the first regulation in the European Union to require specific testing and risk assessment for the NM form of a biocidal substance as a part of the information requirements. Ecotoxicological data are one of the pillars of the information requirements in the BPR, but there are currently no standard test guidelines for the ecotoxicity testing of NMs. The overall objective of this work was to investigate the implications of the introduction of nano-specific testing requirements in the BPR and to explore how these might be fulfilled in the case of copper oxide nanoparticles. While there is information and data available in the open literature that could be used to fulfill the BPR information requirements, most of the studies do not take the Organisation for Economic Co-operation and Development’s nanospecific test guidelines into consideration. This makes it difficult for companies as well as regulators to fulfill the BPR information requirements for nanomaterials. In order to enable a nanospecific risk assessment, best practices need to be developed regarding stock suspension preparation and characterization, exposure suspensions preparation, and for conducting ecotoxicological test.

  9. First evaluation of the threat posed by antifouling biocides in the Southern Adriatic Sea.

    PubMed

    Manzo, Sonia; Ansanelli, Giuliana; Parrella, Luisa; Di Landa, Giuseppe; Massanisso, Paolo; Schiavo, Simona; Minopoli, Carmine; Lanza, Bruno; Boggia, Raffaella; Aleksi, Pellumb; Tabaku, Afrim

    2014-08-01

    The CARISMA project (characterization and ecological risk analysis of antifouling biocides in the Southern Adriatic Sea) aims to appraise the quality of the Southern Adriatic Sea between Italy (Apulia region) and Albania and, in particular, the impact due to the use of biocidal antifouling coatings. Under this project, a preliminary survey at the main hot spots of contamination (e.g. ports and marinas) was conducted at the end of the nautical season in 2012. Chemical seawater analyses were complemented with ecotoxicological assays and the results were analyzed by principal component analysis (PCA). As expected, PCA splits the Albanian and Italian ports, according to the different degrees of contamination indicated for the two countries by the experimental data, highlighting the most critical situation in one port of Apulia. In addition, in order to assess the potential adverse ecological effects posed by antifouling agents (i.e. tributyltin (TBT)-irgarol-diuron) on non-target marine organisms, hazard quotients (HQ) were calculated. The results showed a low risk posed by irgarol and diuron whereas the probability of adverse effects was high in the case of TBT.

  10. Antimicrobial efficacy of biocides tested on skin using an ex-vivo test.

    PubMed

    Maillard, J Y; Messager, S; Veillon, R

    1998-12-01

    An ex-vivo test was used to evaluate the activity of antimicrobials against three microorganisms, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus. The ex-vivo test is a carrier test using freshly excised animal skin samples maintained in viable conditions for a short period of time. Skin samples came from a veterinary practice and were excised from either dogs or cats. The antimicrobial activity of povidone iodine, chlorhexidine diacetate, cetrimide and benzalkonium chloride was also evaluated with suspension and glass-carrier tests. Generally, the activity of the antimicrobials tested was reduced when applied to the skin surface. Apart from povidone iodine (2%) against S. aureus, the biocides investigated failed to achieve a 5 log10 reduction in bacterial titre when tested with the ex-vivo method. There was no significant difference in reduction of bacterial titres after treatment with antimicrobials between the glass-carrier and the suspension tests. Furthermore, the drying process of bacterial inoculum was less detrimental on skin than on glass surfaces. This study confirmed that the activity of a biocide tested in suspension or on an inanimate surface did not reflect its activity when tested on skin. Further development of the ex-vivo test may be useful, especially for testing the antimicrobial activity of formulations with antiseptic properties.

  11. Distribution of antifouling biocides and perfluoroalkyl compounds in sediments from selected locations in Indonesian coastal waters.

    PubMed

    Harino, Hiroya; Arifin, Zainal; Rumengan, Inneke F M; Arai, Takaomi; Ohji, Madoka; Miyazaki, Nobuyuki

    2012-07-01

    Coastal marine environments are considered to be the most sensitive areas for the accumulation of organotin (OT) compounds and other emerging new pollutants, such as perfluoroalkyl compounds. Contamination by these compounds is a matter of great concern due to their accumulation and possible negative impact on the coastal environment and organisms. The concentrations of tributyltin (TBT) compounds were greater in Indonesia, i.e., on the order of Bitung > Manado > Jakarta Bay > Gangga Island, and TBT in sediment from Bitung and Manado was the dominant species among butyltin (BT) compounds. Sea Nine 211, diuron, and irgarol 1051 were detected among alternative biocides in Bitung, Manado, and Gangga Island and irgarol 1051 was detected in Jakarta Bay. Perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) in Jakarta Bay were detected at 0.25 to 6.1 μg kg(-1) dry weight (dw) and 0.58 to 3.7 μg kg(-1) dw, respectively, and the concentrations of PFOS at most sampling sites were greater than those of PFOA. Thus, coastal waters from Indonesia have already been contaminated by antifouling biocides and perfluoroalkyl compounds.

  12. Benzalkonium runoff from roofs treated with biocide products - In situ pilot-scale study.

    PubMed

    Gromaire, M C; Van de Voorde, A; Lorgeoux, C; Chebbo, G

    2015-09-15

    Roof maintenance practices often involve the application of biocide products to fight against moss, lichens and algae. The main component of these products is benzalkonium chloride, a mixture of alkyl benzyl dimethyl ammonium chlorides with mainly C12 and C14 alkyl chain lengths, which is toxic for the aquatic environment. This paper describes, on the basis of an in-situ pilot scale study, the evolution of roof runoff contamination over a one year period following the biocide treatment of roof frames. Results show a major contamination of roof runoff immediately after treatment (from 5 to 30 mg/L), followed by an exponential decrease. 175-375 mm of cumulated rainfall is needed before the runoff concentrations become less than EC50 values for fish (280 μg/l). The residual concentration in the runoff water remains above 4 μg/L even after 640 mm of rainfall. The level of benzalkonium ions leaching depends on the roofing material, with lower concentrations and total mass leached from ceramic tiles than from concrete tiles, and on the state of the tile (new or worn out). Mass balance calculations indicate that a large part of the mass of benzalkonium compounds applied to the tiles is lost, probably due to biodegradation processes.

  13. Biocides used in building materials and their leaching behavior to sewer systems.

    PubMed

    Burkhardt, M; Kupper, T; Hean, S; Haag, R; Schmid, P; Kohler, M; Boller, M

    2007-01-01

    There is increasing concern about diffuse pollution of aquatic systems by biocides used in urban areas. We investigated sources and pathways of biocides significant for the pollution of storm water runoff. Main sources seem to be building envelopes, i.e. facades (paints, plasters) and roof sealing membranes. First results from a defined urban catchment drained by a separated sewer system without any agricultural activities reveal a substantial occurrence. Even after the first flush, concentrations of terbutryn, carbendazim, mecoprop as well as Irgarol 1051 and its metabolite exceeded the Swiss water quality standard of 0.1 microg/L. In laboratory experiments, leaching of mecoprop used as a root protection agent in bitumen sheets for roof waterproofing was determined. The concentrations differed in 16 different sheets two orders of magnitude, depending on the product composition. Using optimized products, it is expected to be the most efficient and sustainable way to reduce the environmental impact. To understand transport dynamics and environmental risk, further storm water events will be analyzed. Based on the ongoing project URBIC, first measures will be proposed to limit the release to surface and ground water.

  14. Poly(lactic acid)/TiO₂ nanocomposites as alternative biocidal and antifungal materials.

    PubMed

    Fonseca, Carmen; Ochoa, Almudena; Ulloa, Maria Teresa; Alvarez, Eduardo; Canales, Daniel; Zapata, Paula A

    2015-12-01

    Poly(lactic acid) (PLA) composites with titanium oxide (TiO2) ~10-nm nanoparticles were produced by the melting process and their main properties were evaluated. The nanoparticles are homogeneously dispersed in the matrix with a low degree of agglomeration, as seen by transmission electron microscopy (TEM). The crystallinity temperature increased ~12% when 5 wt.% of TiO2 was added, showing that the nanoparticles acted as nucleating agents this trend was confirmed by optical images. The elastic modulus increased ~54% compared to neat PLA at 5 wt.% of nanoparticles. Despite these improvements, PLA/TiO2 nanocomposites showed lower shear viscosity than neat PLA, possibly reflecting degradation of the polymer due to the particles. Regarding biocidal properties, after 2h of contact the PLA/TiO2 composites with 8 wt.% TiO2 showed a reduction of Escherichia coli colonies of ~82% under no UVA irradiation compared to pure PLA. This biocidal characteristic can be increased under UVA irradiation, with nanocomposites containing 8 wt.% TiO2 killing 94% of the bacteria. The PLA/TiO2 nanocomposites with 8 wt.% were also 99.99% effective against Aspergillus fumigatus under the UVA irradiation.

  15. Downhole Transformation of the Hydraulic Fracturing Fluid Biocide Glutaraldehyde: Implications for Flowback and Produced Water Quality.

    PubMed

    Kahrilas, Genevieve A; Blotevogel, Jens; Corrin, Edward R; Borch, Thomas

    2016-10-18

    Hydraulic fracturing fluid (HFF) additives are used to enhance oil and gas extraction from unconventional shale formations. Several kilometers downhole, these organic chemicals are exposed to temperatures up to 200 °C, pressures above 10 MPa, high salinities, and a pH range from 5-8. Despite this, very little is known about the fate of HFF additives under these extreme conditions. Here, stainless steel reactors are used to simulate the downhole chemistry of the commonly used HFF biocide glutaraldehyde (GA). The results show that GA rapidly (t1/2 < 1 h) autopolymerizes, forming water-soluble dimers and trimers, and eventually precipitates out at high temperatures (∼140 °C) and/or alkaline pH. Interestingly, salinity was found to significantly inhibit GA transformation. Pressure and shale did not affect GA transformation and/or removal from the bulk fluid. On the basis of experimental pseudo-second-order rate constants, a kinetic model for GA downhole half-life predictions for any combination of these conditions within the limits tested was developed. These findings illustrate that the biocidal GA monomer has limited time to control microbial activity in hot and/or alkaline shales, and may return along with its aqueous transformation products to the surface via flowback and produced water in cooler, more acidic, and saline shales.

  16. Disappointing reliability of pulsatility indices to identify candidates for magnetic resonance imaging screening in population-based studies assessing prevalence of cerebral small vessel disease

    PubMed Central

    Del Brutto, Oscar H.; Mera, Robertino M.; Andrade, María de la Luz; Castillo, Pablo R.; Zambrano, Mauricio; Nader, Juan A.

    2015-01-01

    Background: Diagnosis of cerebral small vessel disease (SVD) is a challenge in remote areas where magnetic resonance imaging (MRI) is not available. Hospital-based studies in high-risk or stroke patients have found an association between the pulsatility index (PI) of intracranial arteries – as derived from transcranial Doppler (TCD) – and white matter hyperintensities (WMH) of presumed vascular origin. We aimed to assess the reliability of cerebral pulsatility indices to identify candidates for MRI screening in population-based studies assessing prevalence of SVD. Methods: A representative sample of stroke-free Atahualpa residents aged ≥65 years investigated with MRI underwent TCD. Using generalized linear models, we evaluated whether the PI of major intracranial arteries correlate with WMH (used as a proxy of diffuse SVD), after adjusting for demographics and cardiovascular risk factors. Results: Out of 70 participants (mean age 70.6 ± 4.6 years, 57% women), 28 (40%) had moderate-to-severe WMH. In multivariate models, there were no differences across categories of WMH in the mean PI of middle cerebral arteries (1.10 ± 0.16 vs. 1.22 ± 0.24, β: 0.065, 95% confidence interval (CI): −0.084–0.177, P = 0.474) or vertebrobasilar arteries (1.11 ± 0.16 vs. 1.29 ± 0.27, β: 0.066, 95% CI: −0.0024–0.156, P = 0.146). Conclusions: Cerebral PI should not be used to identify candidates for MRI screening in population-based studies assessing the burden of SVD. PMID:26167015

  17. Determination of biocides as well as some biocide metabolites from facade run-off waters by solid phase extraction and high performance liquid chromatographic separation and tandem mass spectrometry detection.

    PubMed

    Bester, K; Lamani, X

    2010-08-06

    Biocides are used to protect buildings, boats, and other materials from microbial infestations. A huge variety of compounds are being used: isothiazolinones, e.g., to prevent bacterial growth in paints, triazines and phenylureas against algal growth on water exposed materials while carbamates are used against fungal investations. However these biocides can be leached from the respective materials. As these are very effective compounds it is important to know the concentrations of these biocides in the leachates as well as their leaching behaviour to assess their risk to the environment. In this study, a method for the determination of biocides from facade material run-off water by means of high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) was developed. Due to the amphiphilic character and the expected varying pH-values in the samples, the extractions as well as the HPLC-method development proved to be demanding. The water samples (leachates) were buffered with a phosphate buffer to pH 7. As some of the biocides are very hydrophilic, different SPE cartridges were tested to identify the SPE material with the highest recovery rates for all compounds. For gaining a good separation, analyte trapping was performed on the HPLC column. Quantification was performed using a mass spectrometer in multi-reaction monitoring with two transitions per compound. The final recovery rates were conducted using a cartridge with a divenylbenzyl polymer sorbent. A combination of methanol and acetonitrile as eluents was used to reach recovery rates in the range of 70-100%. The limit of quantification for the compounds of interest ranged from 0.01 to 0.1 microg/L.

  18. Synthesis, characterization, and biocide properties of semicarbazide-formaldehyde resin and its polymer metal complexes.

    PubMed

    Nishat, Nahid; Ahamad, Tansir; Alshehri, Saad M; Parveen, Shadma

    2010-04-01

    Semicarbazide-formaldehyde resin (SFRs) was prepared by the condensation of semicarbazide with formaldehyde in an acidic medium and its polymer metal complexes were prepared with transition metal ions. All the synthesized polymers were characterized by elemental analysis, FTIR, (1)H NMR, (13)C NMR, electronic spectroscopy, magnetic moment measurement and thermogravimetric analyses. The percentage of metal in all the polymer metal complexes was found to be consistent with 2:1 (resin: metal) stoichiometry. The magnetic susceptibility measurement and electronic spectra of all the polymer metal complexes confirmed the geometry of the complexes. All the synthesized polymeric compounds have been screened in vitro against Bacillus subtilis, Staphylococcus aureus (Gram-positive) and Escherichia coli, Salmonella typhi (Gram-negative) using shaking flask method. The entire polymer metal complexes showed excellent anti-bacterial activity and low toxicity when compared with their parental polymeric resin. The anti-bacterial activity and toxicity of the entire synthesized compound is significant and they can be used as antimicrobial as well as anticancer agents for mammals in future.

  19. Compatibility Study of Silver Biocide in Drinking Water with Candidate Metals for Crew Exploration Vehicle Potable Water System

    NASA Technical Reports Server (NTRS)

    Adam, Niklas M.

    2009-01-01

    The stability of silver biocide, used to keep drinking water on the CEV potable water sterile, is unknown as the system design is still in progress. Silver biocide in water can deplete rapidly when exposed to various metal surfaces. Additionally, silver depletion rates may be affected by the surface-area-to-volume (SA/V) ratios in the water system. Therefore, to facilitate the CEV water system design, it would be advantageous to know the biocide depletion rates in water exposed to the surfaces of these candidate metals at various SA/V ratios. Certain surface treatments can be employed to reduce the depletion rates of silver compared to the base metal. The purpose of this work is to determine the compatibility of specific spaceflight-certified metals that could used in the design of the CEV potable water system with silver biocide as well as understand the effect of surface are to volume ratios of metals used in the construction of the potable water system on the silver concentration.

  20. Pollution of modern metalworking fluids containing biocides by pathogenic bacteria in France. Reexamination of chemical treatments accuracy.

    PubMed

    Chazal, P M

    1995-02-01

    Pollution by pathogenic bacteria was examined in 150 French metalworking fluid samples. Gram-negative micro-organisms such as Salmonella spp., Shigella spp., and Vibrio spp. as well as Gram-positive cocci were never isolated. Nevertheless opportunistic pathogens such as Pseudomonas aeruginosa and Klebsiella pneumoniae still contaminated these fluids with an isolation frequency of 17% of samples for each. These two micro-organisms failed to grow or even survive in vitro in sterile cutting fluids protected by biocides. Preliminary growth of other micro-organisms such as Pseudomonas putida or Pseudomonas fluorescens, which are the major part of the indigenous microflora, seemed to be a prerequisite for their growth. These former two Pseudomonas could resist three different classes of biocides and, at least in the case of formaldehyde-releasers, adaptation was followed by biocide deterioration. Resistance magnification was observed in the presence of the three different types of biocides and, in the case of formaldehyde releasers the resistance and deterioration levels were close to those recommended by the manufacturers. This is probably the reason why the preliminary growth of Pseudomonas putida allowed in vitro differed growth of Klebsiella pneumoniae and Pseudomonas aeruginosa. Due to relatively high isolation frequencies of opportunistic pathogens (17% of samples) periodical microbiological examination of cutting fluids should be carried out in order to evaluate risks for human health. Wearing masks and gloves is still recommended, at least in France.

  1. A Novel Assay for Screening Inhibitors Targeting HIV Integrase LEDGF/p75 Interaction Based on Ni2+ Coated Magnetic Agarose Beads

    PubMed Central

    Dawei, Zhang; Hongqiu, He; Mengmeng, Liu; Zhixia, Meng; Shunxing, Guo

    2016-01-01

    HIV-1 integrase (IN) plays an essential role in viral replication and thus serves as an important target for chemotherapeutic intervention against HIV-1 infection. However, the current three clinical IN inhibitors, raltegravir, elvitegravir and dolutegravir share the same inhibitory mechanism, resulting in a common clinical resistance profile which have emerged in infected patients receiving treatment. Therefore, it is important to develop small molecule inhibitors that impair IN function with distinct mechanisms of action. In this work, a magnetic-beads based biochemical assay targeting the protein-protein interaction (PPI) between HIV IN and the cellular cofactor LEDGF/p75 was developed for identification of HIV-1 IN inhibitors. Furthermore, a library containing 1000 US. Food and Drug Administration (FDA)-approved drugs currently used for human medication was screened to identify inhibitors targeting the PPI. The assay was proved to be quite robust and with the novel assay we successfully identified dexlansoprazole (IC50 of 4.8 μM), a FDA-approved proton pump inhibitor, as a potential inhibitor for the PPI between IN and LEDGF/p75, which bound to the LEDGF/p75 partner with a kinetic dissociation (Kd) constant of 330 nM ± 2.6 nM. PMID:27633629

  2. Metal Iodate-Based Energetic Composites and Their Combustion and Biocidal Performance.

    PubMed

    Wang, H; Jian, G; Zhou, W; DeLisio, J B; Lee, V T; Zachariah, M R

    2015-08-12

    The biological agents that can be weaponized, such as Bacillus anthracis, pose a considerable potential public threat. Bacterial spores, in particular, are highly stress resistant and cannot be completely neutralized by common bactericides. This paper reports on synthesis of metal iodate-based aluminized electrospray-assembled nanocomposites which neutralize spores through a combined thermal and chemical mechanism. Here metal iodates (Bi(IO3)3, Cu(IO3)2, and Fe(IO3)3) act as a strong oxidizer to nanoaluminum to yield a very exothermic and violent reaction, and simultaneously generate iodine as a long-lived bactericide. These microparticle-assembled nanocomposites when characterized in terms of reaction times and temporal pressure release show significantly improved reactivity. Furthermore, sporicidal performance superior to conventional metal-oxide-based thermites clearly shows the advantages of combining both a thermal and biocidal mechanism in spore neutralization.

  3. Comparative biocidal activity of peracetic acid, benzalkonium chloride and ortho-phthalaldehyde on 77 bacterial strains.

    PubMed

    Bridier, A; Briandet, R; Thomas, V; Dubois-Brissonnet, F

    2011-07-01

    Despite numerous reports on biocide activities, it is often difficult to have a reliable and relevant overview of bacterial resistance to disinfectants because each work challenges a limited number of strains and tested methods are often different. The aim of this study was to evaluate the bactericidal activity of three different disinfectants commonly used in industrial or medical environments (peracetic acid, benzalkonium chloride and ortho-phthalaldehyde) against 77 bacterial strains from different origins using one standard test method (NF EN 1040). Results highlight the existence of high interspecific variability of resistance to disinfectants and, contrary to widespread belief, Gram-positive strains generally appeared more resistant than Gram-negative strains. Resistance was also variable among strains of the same species such as Bacillus subtilis to peracetic acid, Pseudomonas aeruginosa to benzalkonium chloride and Staphylococcus aureus to ortho-phthalaldehyde.

  4. A reference protocol for comparing the biocidal properties of gas plasma generating devices

    NASA Astrophysics Data System (ADS)

    Shaw, A.; Seri, P.; Borghi, C. A.; Shama, G.; Iza, F.

    2015-12-01

    Growing interest in the use of non-thermal, atmospheric pressure gas plasmas for decontamination purposes has resulted in a multiplicity of plasma-generating devices. There is currently no universally approved method of comparing the biocidal performance of such devices and in the work described here spores of the Gram positive bacterium Bacillus subtilis (ATCC 6633) are proposed as a suitable reference biological agent. In order to achieve consistency in the form in which the biological agent in question is presented to the plasma, a polycarbonate membrane loaded with a monolayer of spores is proposed. The advantages of the proposed protocol are evaluated by comparing inactivation tests in which an alternative microorganism (methicillin resistant Staphylococcus aureus—MRSA) and the widely-used sample preparation technique of directly pipetting cell suspensions onto membranes are employed. In all cases, inactivation tests with either UV irradiation or plasma exposure were more reproducible when the proposed protocol was followed.

  5. Toxic indole alkaloids avrainvillamide and stephacidin B produced by a biocide tolerant indoor mold Aspergillus westerdijkiae.

    PubMed

    Mikkola, Raimo; Andersson, Maria A; Hautaniemi, Maria; Salkinoja-Salonen, Mirja S

    2015-06-01

    Toxic Aspergillus westerdijkiae were present in house dust and indoor air fall-out from a residence and a kindergarten where the occupants suffered from building related ill health. The A. westerdijkiae isolates produced indole alkaloids avrainvillamide (445 Da) and its dimer stephacidin B (890 Da). It grew and sporulated in presence of high concentrations of boron or polyguanidine (PHMB, PHMG) based antimicrobial biocides used to remediate mold infested buildings. The boar sperm cells were used as sensor cells to purify toxins from HPLC fractions of the fungal biomass. Submicromolar concentrations (EC50 0.3-0.4 μM) blocked boar spermatozoan motility and killed porcine kidney tubular epithelial cells (PK-15). Plate grown hyphal mass of the A. westerdijkiae isolates contained 300-750 ng of avrainvillamide and 30-300 ng of stephacidin B per mg (wet weight). The toxins induced rapid (30 min) loss of boar sperm motility, followed (24 h) by loss of mitochondrial membrane potential (ΔΨm). Apoptotic cell death was observed in PK-15 cell monolayers, prior to cessation of glucose uptake or loss of ΔΨm. Avrainvillamide and stephacidin B were 100-fold more potent towards the porcine cells than the mycotoxins stephacidin A, ochratoxin A, sterigmatocystin and citrinin. The high toxicity of stephacidin B indicates a role of nitrone group in the mechanism of toxicity. Avrainvillamide and stephacidin B represent a new class of toxins with possible a threat to human health in buildings. Furthermore, the use of biocides highly enhanced the growth of toxigenic A. westerdijkiae.

  6. Acanthamoeba encystment: multifactorial effects of buffers, biocides, and demulcents present in contact lens care solutions

    PubMed Central

    Kovacs, Christopher J; Lynch, Shawn C; Rah, Marjorie J; Millard, Kimberly A; Morris, Timothy W

    2015-01-01

    Purpose To determine whether agents which are purportedly capable of inducing encystment of Acanthamoeba can recapitulate the signal when tested in differing formulations. Methods In accordance with the International Standard ISO 19045, Acanthamoeba castellanii ATCC 50370 trophozoites were cultured in antibiotic-free axenic medium, treated with test solutions, and encystment rates plus viability were measured via bright field and fluorescent microscopy. Test solutions included phosphate-buffered saline (PBS), borate-buffered saline, biguanide- and hydrogen peroxide (H2O2)-based biocides, propylene glycol (PG) and povidone (POV) ophthalmic demulcents, and one-step H2O2-based contact lens disinfection systems. Results Only PBS solutions with 0.25 ppm polyaminopropyl biguanide (PAPB) and increasing concentrations of PG and POV stimulated A. castellanii encystment in a dose-dependent manner, whereas PBS solutions containing 3% H2O2 and increasing concentrations of PG and POV did not stimulate encystment. Borate-buffered saline and PBS/citrate solutions containing PG also did not stimulate encystment. In addition, no encystment was observed after 24 hours, 7 days, or 14 days of exposures of trophozoites to one-step H2O2 contact lens disinfection products or related solutions. Conclusion The lack of any encystment observed when trophozoites were treated with existing or new one-step H2O2 contact lens care products, as well as when trophozoites were exposed to various related test solutions, confirms that Acanthamoeba encystment is a complex process which depends upon simultaneous contributions of multiple factors including buffers, biocides, and demulcents. PMID:26508829

  7. Inactivation of Bacillus anthracis Spores by Liquid Biocides in the Presence of Food Residue▿

    PubMed Central

    Hilgren, J.; Swanson, K. M. J.; Diez-Gonzalez, F.; Cords, B.

    2007-01-01

    Biocide inactivation of Bacillus anthracis spores in the presence of food residues after a 10-min treatment time was investigated. Spores of nonvirulent Bacillus anthracis strains 7702, ANR-1, and 9131 were mixed with water, flour paste, whole milk, or egg yolk emulsion and dried onto stainless-steel carriers. The carriers were exposed to various concentrations of peroxyacetic acid, sodium hypochlorite (NaOCl), or hydrogen peroxide (H2O2) for 10 min at 10, 20, or 30°C, after which time the survivors were quantified. The relationship between peroxyacetic acid concentration, H2O2 concentration, and spore inactivation followed a sigmoid curve that was accurately described using a four-parameter logistic model. At 20°C, the minimum concentrations of peroxyacetic acid, H2O2, and NaOCl (as total available chlorine) predicted to inactivate 6 log10 CFU of B. anthracis spores with no food residue present were 1.05, 23.0, and 0.78%, respectively. At 10°C, sodium hypochlorite at 5% total available chlorine did not inactivate more than 4 log10 CFU. The presence of the food residues had only a minimal effect on peroxyacetic acid and H2O2 sporicidal efficacy, but the efficacy of sodium hypochlorite was markedly inhibited by whole-milk and egg yolk residues. Sodium hypochlorite at 5% total available chlorine provided no greater than a 2-log10 CFU reduction when spores were in the presence of egg yolk residue. This research provides new information regarding the usefulness of peroxygen biocides for B. anthracis spore inactivation when food residue is present. This work also provides guidance for adjusting decontamination procedures for food-soiled and cold surfaces. PMID:17720823

  8. Dynamics of biocide emissions from buildings in a suburban stormwater catchment - concentrations, mass loads and emission processes.

    PubMed

    Bollmann, Ulla E; Vollertsen, Jes; Carmeliet, Jan; Bester, Kai

    2014-06-01

    Biocides such as isothiazolinones, carbamates, triazines, phenylureas, azoles and others are used to protect the surfaces of buildings, e.g. painted or unpainted render or wood. These biocides can be mobilized from the materials if rainwater gets into contact with these buildings. Hence, these biocides will be found in rainwater runoff (stormwater) from buildings that is traditionally managed as "clean water" in stormwater sewer systems and often directly discharged into surface waters without further treatment. By means of a 9 month event-based high resolution sampling campaign the biocide emissions in a small suburban stormwater catchment were analysed and the emission dynamics throughout the single rain events were investigated. Five out of twelve of the rain events (peak events) proved significantly higher concentrations than the rest (average) for at least one compound. Highest median concentrations of 0.045 and 0.052 μg L(-1) were found for terbutryn and carbendazim, while the concentrations for isoproturon, diuron, N-octylisothiazolinone, benzoisothiazolinone, cybutryn, propiconazole, tebuconazole, and mecoprop were one order of magnitude lower. However, during the peak events the concentrations reached up to 1.8 and 0.3 μg L(-1) for terbutryn and carbendazim, respectively. Emissions of an averaged single family house into the stormwater sewer turned out to be 59 and 50 μg event(-1) house(-1) terbutryn and carbendazim, respectively. Emissions for the other biocides ranged from 0.1 to 11 μg event(-1) house(-1). Mass load analysis revealed that peak events contributed in single events as much to the emissions as 11 average events. However, the mass loads were highly dependent on the amounts of rainwater, i.e. the hydraulic flow in the receiving sewer pipe. The analysis of the emission dynamics showed first flush emissions only for single parameters in three events out of twelve. Generally biocides seemed to be introduced into the stormwater system

  9. Biocides in urban wastewater treatment plant influent at dry and wet weather: concentrations, mass flows and possible sources.

    PubMed

    Bollmann, Ulla E; Tang, Camilla; Eriksson, Eva; Jönsson, Karin; Vollertsen, Jes; Bester, Kai

    2014-09-01

    In recent years, exterior thermal insulation systems became more and more important leading to an increasing amount of houses equipped with biocide-containing organic façade coatings or fungicide treated wood. It is known that these biocides, e.g. terbutryn, carbendazim, and diuron, as well as wood preservatives as propiconazole, leach out of the material through contact with wind driven rain. Hence, they are present in combined sewage during rain events in concentrations up to several hundred ng L(-1). The present study focused on the occurrence of these biocides in five wastewater treatment plants in Denmark and Sweden during dry and wet weather. It was discovered, that biocides are detectable not only during wet weather but also during dry weather when leaching from façade coatings can be excluded as source. In most cases, the concentrations during dry weather were in the same range as during wet weather (up to 100 ng L(-1)); however, for propiconazole noteworthy high concentrations were detected in one catchment (4.5 μg L(-1)). Time resolved sampling (12 × 2 h) enabled assessments about possible sources. The highest mass loads during wet weather were detected when the rain was heaviest (e.g. up to 116 mg h(-1) carbendazim or 73 mg h(-1) mecoprop) supporting the hypothesis that the biocides were washed off by wind driven rain. Contrary, the biocide emissions during dry weather were rather related to household activities than with emissions from buildings, i.e., emissions were highest during morning and evening hours (up to 50 mg h(-1)). Emissions during night were significantly lower than during daytime. Only for propiconazole a different emission behaviour during dry weather was observed: the mass load peaked in the late afternoon (3 g h(-1)) and declined slowly afterwards. Most likely this emission was caused by a point source, possibly from inappropriate cleaning of spray equipment for agriculture or gardening.

  10. Concentration patterns of agricultural pesticides and urban biocides in surface waters of a catchment of mixed land use

    NASA Astrophysics Data System (ADS)

    Stamm, C.; Wittmer, I.; Bader, H.-P.; Scheidegger, R.; Alder, A.; Lück, A.; Hanke, I.; Singer, H.

    2009-04-01

    Organic pesticides and biocides that are found in surface waters, can originate from agricultural and urban sources. For a long time, agricultural pesticides have received substantially more attention than biocidal compounds from urban use like material protection or in-can preservatives (cosmetics etc.). Recent studies however revealed that the amounts of urban biocides used may exceed those of agricultural pesticides. This study aims at comparing the input of several important pesticides and biocides into a small Swiss stream with a special focus on loss events triggered by rainfall. A set of 16 substances was selected to represent urban and agricultural sources. The selected substances are either only used as biocides (irgarol, isothiazolinones, IPBC), as pesticides (atrazine, sulcotrione, dichlofluanid, tolylfluanid) or have a mixed use (isoproturon, terbutryn, terbutylazine, mecoprop, diazinon, carbendazim) The study catchment has an area of 25 km2 and is inhabited by about 12'000 people. Four sampling sites were selected in the river system in order to reflect different urban and agricultural sources. Additionally, we sampled a combined sewer overflow, a rain sewer and the outflow of a wastewater treatment plant. At each site discharge was measured continuously from March to November 2007. During 16 rain events samples were taken by automatic devices at a high temporal resolution. The results, based on more than 500 analyzed samples, revealed distinct concentration patterns for different compounds and sources. Agricultural pesticides exhibited a strong seasonality as expected based on the application periods. During the first one or two rain events after application the concentrations reached up to several thousand ng/l during peak flow (atrazine, isoproturon). The temporal patterns of urban biocides were more diverse. Some compounds obviously stem from permanent sources independent of rainfall because they were found mostly in the outlet of the wastewater

  11. Evaluation of epidemiological cut-off values indicates that biocide resistant subpopulations are uncommon in natural isolates of clinically-relevant microorganisms.

    PubMed

    Morrissey, Ian; Oggioni, Marco Rinaldo; Knight, Daniel; Curiao, Tania; Coque, Teresa; Kalkanci, Ayse; Martinez, Jose Luis

    2014-01-01

    To date there are no clear criteria to determine whether a microbe is susceptible to biocides or not. As a starting point for distinguishing between wild-type and resistant organisms, we set out to determine the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) distributions for four common biocides; triclosan, benzalkonium chloride, chlorhexidine and sodium hypochlorite for 3319 clinical isolates, with a particular focus on Staphylococcus aureus (N = 1635) and Salmonella spp. (N = 901) but also including Escherichia coli (N = 368), Candida albicans (N = 200), Klebsiella pneumoniae (N = 60), Enterobacter spp. (N = 54), Enterococcus faecium (N = 53), and Enterococcus faecalis (N = 56). From these data epidemiological cut-off values (ECOFFs) are proposed. As would be expected, MBCs were higher than MICs for all biocides. In most cases both values followed a normal distribution. Bimodal distributions, indicating the existence of biocide resistant subpopulations were observed for Enterobacter chlorhexidine susceptibility (both MICs and MBCs) and the susceptibility to triclosan of Enterobacter (MBC), E. coli (MBC and MIC) and S. aureus (MBC and MIC). There is a concern on the potential selection of antibiotic resistance by biocides. Our results indicate however that resistance to biocides and, hence any potential association with antibiotic resistance, is uncommon in natural populations of clinically relevant microorganisms.

  12. The role of kaolin particles in the performance of a carbamate-based biocide for water bacterial control.

    PubMed

    Pereira, Maria Olivia; Vieira, Maria João; Melo, Luis F

    2002-01-01

    The influence of kaolin particles on the activity of Pseudomonas fluorescens and on the efficacy of a carbamate-based biocide was investigated. The results indicated that kaolin particles stimulated the activity of the bacteria for all buffered pH values studied (5, 7, and 9); this effect being more evident for the tests carried out at pH 5 and 9. The presence of the clay in P. fluorescens suspensions decreased the efficiency of disinfection of the carbamate. The results also showed that kaolin was very effective in removing carbamate from the culture media. Therefore, the biocide concentration in the solution decreased, and consequently its availability to the bacteria was reduced. The results could be explained by the interaction between kaolin particles and carbamate and by the changes in the configuration of kaolin aggregates, depending on the pH value.

  13. Toxicity of anti-fouling biocides to encysted metacercariae of Echinoparyphium recurvatum (Digenea: Echinostomatidae) and their snail hosts.

    PubMed

    Morley, N J; Leung, K M Y; Morritt, D; Crane, M

    2004-07-01

    The toxicity of the anti-fouling biocides tributyltin (TBTO), copper, and Irgarol 1051 (irgarol) at a nominal concentration of 10 microg/l over a 30 day period were investigated against the viability of metacercarial cysts of the digenean parasite Echinoparyphium recurvatum resident within the body of two common freshwater snails, Lymnaea peregra and Physa fontinalis. Reduced parasite viability was found under most exposures in both snail species. However a greater effect of toxicant exposure was found in cysts within P. fontinalis compared to those in L. peregra. This was associated with an increased mortality of the host snail. Among all tested biocides, TBTO exposures induced the highest mortality to both the parasite and their hosts. These results suggest that parasite viability is interlinked with survival of the host snail. The mechanisms of differing toxicity between host species and its relevance to successful parasite transmission to the next host are discussed.

  14. The influence of sodium hypochlorite biocide on the corrosion of carbon steel in reclaimed water used as circulating cooling water

    NASA Astrophysics Data System (ADS)

    Su, Weina; Tian, Yimei; Peng, Sen

    2014-10-01

    In this paper, we investigated the influence of sodium hypochlorite (NaClO) biocide on the corrosion of carbon steel in four different conditions during one dosing cycle. The results from the polarisation curve and electrochemical impedance spectroscopy (EIS) indicated that NaClO could affect the activity of microorganisms, leading to corrosion inhibition. The equivalent circuits had two time constants in the presence of biocide, which suggested that an oxide layer of NaClO was formed on the carbon steel surface. Environmental scanning electron microscopy (ESEM) and energy dispersive spectroscopy (EDS) were both employed to demonstrate that NaClO produced a good antibacterial activity, thereby indirectly retarding corrosion while simultaneously inhibiting scaling.

  15. The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor.

    PubMed

    Minnoş, Bihter; Ilhan-Sungur, Esra; Çotuk, Ayşın; Güngör, Nihal Doğruöz; Cansever, Nurhan

    2013-01-01

    The corrosion behaviour of galvanized steel in cooling tower water containing a biocide and a corrosion inhibitor was investigated over a 10-month period in a hotel. Planktonic and sessile numbers of sulphate reducing bacteria (SRB) and heterotrophic bacteria were monitored. The corrosion rate was determined by the weight loss method. The corrosion products were analyzed by energy dispersive X-ray spectroscopy and X-ray diffraction. A mineralized, heterogeneous biofilm was observed on the coupons. Although a biocide and a corrosion inhibitor were regularly added to the cooling water, the results showed that microorganisms, such as SRB in the mixed species biofilm, caused corrosion of galvanized steel. It was observed that Zn layers on the test coupons were completely depleted after 3 months. The Fe concentrations in the biofilm showed significant correlations with the weight loss and carbohydrate concentration (respectively, p < 0.01 and p < 0.01).

  16. Quorum Sensing and the Use of Quorum Quenchers as Natural Biocides to Inhibit Sulfate-Reducing Bacteria

    PubMed Central

    Scarascia, Giantommaso; Wang, Tiannyu; Hong, Pei-Ying

    2016-01-01

    Sulfate-reducing bacteria (SRB) are one of the main protagonist groups of biocorrosion in the seawater environment. Given their principal role in biocorrosion, it remains a crucial task to develop strategies to reduce the abundance of SRBs. Conventional approaches include the use of biocides and antibiotics, which can impose health, safety, and environmental concerns. This review examines an alternative approach to this problem. This is achieved by reviewing the role of quorum sensing (QS) in SRB populations and its impact on the biofilm formation process. Genome databases of SRBs are mined to look for putative QS systems and homologous protein sequences representative of autoinducer receptors or synthases. Subsequently, this review puts forward the potential use of quorum quenchers as natural biocides against SRBs and outlines the potential strategies for the implementation of this approach. PMID:27983678

  17. Inactivation of Yersinia pseudotuberculosis, as a surrogate for Yersinia pestis, by liquid biocides in the presence of food residue.

    PubMed

    Hilgren, J; Swanson, K M J; Diez-Gonzalez, F; Cords, B

    2009-02-01

    The efficacy of liquid biocides is influenced by surface cleanliness, treatment time, and temperature. Experiments were completed to measure the impact of these variables on the ability of commercial biocides to inactivate Yersinia pseudotuberculosis ATCC 29910, as a surrogate for Yersinia pestis, in the presence of food residues. The test organism was mixed with water, milk, flour, or egg yolk and then dried onto stainless steel coupons. Coupons were then exposed to sodium hypochlorite, acidified sodium chlorite, a quaternary ammonium compound, an iodophor, hydrogen peroxide, peroxyacetic acid, or a peroxy-fatty acid mixture, for 10 or 30 min at 10, 20, or 30 degrees C. For all biocides except the iodophor, manufacturer-recommended disinfection levels applied for 10 min at 20 degrees C resulted in 5-log reductions of the test organism dried alone or with flour. However, in the presence of whole milk or egg yolk residue, markedly higher sodium hypochlorite, peroxyacetic acid, peroxy-fatty acid mixture, quaternary ammonium compound, and iodophor concentrations were needed to achieve the 5-log reductions. Further, the quaternary ammonium compound was incapable of achieving 5-log reductions in 10 min in the presence of milk and egg yolk residues. Hydrogen peroxide and acidified sodium chlorite disinfection levels (7.5% and 2500 ppm, respectively) achieved 5-log reductions under all test conditions. These results suggest that commercial disinfectants can adequately decontaminate clean surfaces contaminated with Y. pseudotuberculosis and Y. pestis. These results also provide guidance on the feasibility of overcoming the negative influence of food residues on disinfection by adjusting biocide exposure time, temperature, and concentration.

  18. Isothiazolone Volatility Study of a Water Bottom from Fuel Treated with Kathon(trade name) FP1.5 Biocide

    DTIC Science & Technology

    1993-11-01

    specific biocides was evaluated. Pure cultures of Hormonoconis resinae (previously Cladosporium resinae ), Yarrowia lipolytica and Pseudomonas...R.A., "Growth of Cladosporium resinae in Sea Water/Fuel Systems", Developments in Industrial Microbiology, 22, 781 (1981). 5 MacGregor C. and Devitt S...Contractor Report CR/87/431, (1987). 8 Hebda A.J. and Jones G.M., "Conditions and Modifications to Conditions for Growth of C. resinae in Canadian

  19. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia

    PubMed Central

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure. PMID:26201074

  20. Predictive Studies Suggest that the Risk for the Selection of Antibiotic Resistance by Biocides Is Likely Low in Stenotrophomonas maltophilia.

    PubMed

    Sánchez, María Blanca; Decorosi, Francesca; Viti, Carlo; Oggioni, Marco Rinaldo; Martínez, José Luis; Hernández, Alvaro

    2015-01-01

    Biocides are used without restriction for several purposes. As a consequence, large amounts of biocides are released without any control in the environment, a situation that can challenge the microbial population dynamics, including selection of antibiotic resistant bacteria. Previous work has shown that triclosan selects Stenotrophomonas maltophilia antibiotic resistant mutants overexpressing the efflux pump SmeDEF and induces expression of this pump triggering transient low-level resistance. In the present work we analyze if two other common biocides, benzalkonium chloride and hexachlorophene, trigger antibiotic resistance in S. maltophilia. Bioinformatic and biochemical methods showed that benzalkonium chloride and hexachlorophene bind the repressor of smeDEF, SmeT. Only benzalkonium chloride triggers expression of smeD and its effect in transient antibiotic resistance is minor. None of the hexachlorophene-selected mutants was antibiotic resistant. Two benzalkonium chloride resistant mutants presented reduced susceptibility to antibiotics and were impaired in growth. Metabolic profiling showed they were more proficient than their parental strain in the use of some dipeptides. We can then conclude that although bioinformatic predictions and biochemical studies suggest that both hexachlorophene and benzalkonium chloride should induce smeDEF expression leading to transient S. maltophilia resistance to antibiotics, phenotypic assays showed this not to be true. The facts that hexachlorophene resistant mutants are not antibiotic resistant and that the benzalkonium chloride resistant mutants presenting altered susceptibility to antibiotics were impaired in growth suggests that the risk for the selection (and fixation) of S. maltophilia antibiotic resistant mutants by these biocides is likely low, at least in the absence of constant selection pressure.

  1. Comparative analysis of Salmonella susceptibility and tolerance to the biocide chlorhexidine identifies a complex cellular defense network

    PubMed Central

    Condell, Orla; Power, Karen A.; Händler, Kristian; Finn, Sarah; Sheridan, Aine; Sergeant, Kjell; Renaut, Jenny; Burgess, Catherine M.; Hinton, Jay C. D.; Nally, Jarlath E.; Fanning, Séamus

    2014-01-01

    Chlorhexidine is one of the most widely used biocides in health and agricultural settings as well as in the modern food industry. It is a cationic biocide of the biguanide class. Details of its mechanism of action are largely unknown. The frequent use of chlorhexidine has been questioned recently, amidst concerns that an overuse of this compound may select for bacteria displaying an altered susceptibility to antimicrobials, including clinically important anti-bacterial agents. We generated a Salmonella enterica serovar Typhimurium isolate (ST24CHX) that exhibited a high-level tolerant phenotype to chlorhexidine, following several rounds of in vitro selection, using sub-lethal concentrations of the biocide. This mutant showed altered suceptibility to a panel of clinically important antimicrobial compounds. Here we describe a genomic, transcriptomic, proteomic, and phenotypic analysis of the chlorhexidine tolerant S. Typhimurium compared with its isogenic sensitive progenitor. Results from this study describe a chlorhexidine defense network that functions in both the reference chlorhexidine sensitive isolate and the tolerant mutant. The defense network involved multiple cell targets including those associated with the synthesis and modification of the cell wall, the SOS response, virulence, and a shift in cellular metabolism toward anoxic pathways, some of which were regulated by CreB and Fur. In addition, results indicated that chlorhexidine tolerance was associated with more extensive modifications of the same cellular processes involved in this proposed network, as well as a divergent defense response involving the up-regulation of additional targets such as the flagellar apparatus and an altered cellular phosphate metabolism. These data show that sub-lethal concentrations of chlorhexidine induce distinct changes in exposed Salmonella, and our findings provide insights into the mechanisms of action and tolerance to this biocidal agent. PMID:25136333

  2. A synergistic D-tyrosine and tetrakis hydroxymethyl phosphonium sulfate biocide combination for the mitigation of an SRB biofilm.

    PubMed

    Xu, D; Li, Y; Gu, T

    2012-10-01

    Microbiologically influenced corrosion (MIC) is a major problem in various industries such as oil and gas, and water utilities. Billions of dollars are lost to microbiologically influenced corrosion (MIC) each year in the US. The key to MIC control is biofilm mitigation. Sulfate-reducing bacteria (SRB) are often the culprits. They are also involved in souring and biofouling. SRB biofilms are notoriously difficult to eradicate. Due to environmental concerns and increasing costs, better biocide treatment strategies are desired. Recent studies suggested that D-tyrosine and some other D-amino acids may signal biofilm dispersal. Experimental results in this work indicated that D-tyrosine is an effective biocide enhancer for tetrakis hydroxymethyl phosphonium sulfate (THPS) that is a green biocide. Desulfovibrio vulgaris (ATCC 7757) was used in biofilm prevention and biofilm removal tests. It was found that 100 ppm D-tyrosine alone and 50 ppm THPS alone were both ineffective against the SRB biofilm. However, when 1 ppm D-tyrosine was combined with 50 ppm THPS, the synergy between the two chemicals successfully prevented the establishment of the SRB biofilm on C1018 mild steel coupon surfaces in batch treatment tests. It also eradicated established SRB biofilms from coupon surfaces in both 1 and 3-h shock treatment tests.

  3. Comparison of two biocides--carbamate and glutaraldehyde--in the control of fouling in pulp and paper industry.

    PubMed

    Pereira, M O; Vieira, M J; Beleza, V M; Melo, L F

    2001-07-01

    Formation of fouling deposits is a serious problem facing paper mills. Despite the search for alternative methods, chemical biocides still represent the chief countermeasure to control microbial growth and general fouling buid-up in pulp and paper mills. The purpose of this work was to determine the effect of two biocides (carbamate and glutaraldehyde) on both planktonic cells and fouling layers of a paper machine system. A flow system was used for the study of fouling accumulation in an industrial white water circuit. Both biocides proved to be more effective in reducing the microbial loading of the white water circuit than the deposit accumulated on the stainless steel surfaces. Carbamate, in contrast to glutaraldehyde, had the ability of promoting cell agglomeration since the microbial loading decreased much more when the white water, treated with carbamate, was filtered through a filter-linen. The retention of suspended cells in the cellulose fibres acquires major importance since it is obtained by using an already existing physical process (filtration), which strongly enhances the overall microbial reduction obtained with the addition of the carbamate, without increasing the economic costs. These results also suggest that the use of conventional retention agents in pulp and paper processes can be efficient in controlling unwanted microbial effects.

  4. Impact of the biocide Irgarol on meiofauna and prokaryotes from the sediments of the Bizerte lagoon-an experimental study.

    PubMed

    Hannachi, Amel; Elarbaoui, Soumaya; Khazri, Abdelhafidh; Sellami, Badreddine; Rastelli, Eugenio; D'Agostino, Fabio; Beyrem, Hamouda; Mahmoudi, Ezzeddine; Corinaldesi, Cinzia; Danovaro, Roberto

    2016-04-01

    The biocide Irgarol 1051 has been reported to have negative effects on a large number of living components including non-target organisms, but information on its impact on the marine meiofauna and benthic prokaryotes is completely lacking. Here, we report the results of long-term experimental studies in which we determined the effects of increasing Irgarol concentrations (from 11.5 to 315 ng g(-1) sediment dry weight) on meiofauna and benthic prokaryotes. We found that this biocide had a significant impact on meiofauna abundance, even at the lowest concentrations, causing a drastic decline in the abundance of nematodes (the dominant meiofaunal taxon) and an increase of the relative importance of oligochaetes. Even if no direct effects of Irgarol were found on prokaryotic abundance and biomass, the molecular fingerprinting analyses (automated ribosomal intergenic spacer analysis) showed that the prokaryotic diversity was significantly altered by the biocide. The results of the present study indicate that Irgarol 1051 in marine sediments has a significant impact on the smallest eukaryotic and microbial components also at very low concentrations (ca 12 ng g(-1)).

  5. Hydrosol of Thymbra capitata Is a Highly Efficient Biocide against Salmonella enterica Serovar Typhimurium Biofilms

    PubMed Central

    Karampoula, Foteini; Deschamps, Julien; Doulgeraki, Agapi I.; Nychas, George-John E.

    2016-01-01

    ABSTRACT Salmonella is recognized as one of the most significant enteric foodborne bacterial pathogens. In recent years, the resistance of pathogens to biocides and other environmental stresses, especially when they are embedded in biofilm structures, has led to the search for and development of novel antimicrobial strategies capable of displaying both high efficiency and safety. In this direction, the aims of the present work were to evaluate the antimicrobial activity of hydrosol of the Mediterranean spice Thymbra capitata against both planktonic and biofilm cells of Salmonella enterica serovar Typhimurium and to compare its action with that of benzalkonium chloride (BC), a commonly used industrial biocide. In order to achieve this, the disinfectant activity following 6-min treatments was comparatively evaluated for both disinfectants by calculating the concentrations needed to achieve the same log reductions against both types of cells. Their bactericidal effect against biofilm cells was also comparatively determined by in situ and real-time visualization of cell inactivation through the use of time-lapse confocal laser scanning microscopy (CLSM). Interestingly, results revealed that hydrosol was almost equally effective against biofilms and planktonic cells, whereas a 200-times-higher concentration of BC was needed to achieve the same effect against biofilm compared to planktonic cells. Similarly, time-lapse CLSM revealed the significant advantage of the hydrosol to easily penetrate within the biofilm structure and quickly kill the cells, despite the three-dimensional (3D) structure of Salmonella biofilm. IMPORTANCE The results of this paper highlight the significant antimicrobial action of a natural compound, hydrosol of Thymbra capitata, against both planktonic and biofilm cells of a common foodborne pathogen. Hydrosol has numerous advantages as a disinfectant of food-contact surfaces. It is an aqueous solution which can easily be rinsed out from surfaces, it

  6. The wide spectrum high biocidal potency of Bioxy formulation when dissolved in water at different concentrations

    PubMed Central

    Dagher, Fadi

    2017-01-01

    Traditional surface disinfectants that have long been applied in medicine, animal husbandry, manufacturing and institutions are inconvenient at best and dangerous at worst. Moreover, some of these substances have adverse environmental impacts: for example, quaternary ammonium compounds (“quats”) are reproductive toxicants in both fish and mammals. Halogens are corrosive both to metals and living tissues, are highly reactive, can be readily neutralized by metals, and react with organic matter to form toxic, persistent by-products such as dioxins and furans. Aldehydes may be carcinogenic to both human and animals upon repeated exposures, are corrosive, cross-link living tissues and many synthetic materials, and may lose efficacy when pathogens enzymatically adapt to them. Alcohols are flammable and volatile and can be enzymatically degraded by certain bacterial pathogens. Quats are highly irritating to mucous membranes and over time can induce pathogen resistance, especially if they are not alternated with functionally different disinfectants. In contrast, peracetic acid (PAA), a potent oxidizer, liberates hydrogen peroxide (itself a disinfectant), biodegrades to carbon dioxide, water and oxygen, and is at least as efficacious as contact biocides e.g., halogens and aldehydes. Nevertheless, the standard form of liquid PAA is highly corrosive, is neutralized by metals and organic matter, gives off noxious odours and must be stored in vented containers. For the reasons stated above, Bioxy formulations were developed, a series of powder forms of PAA, which are odourless, stable in storage and safe to transport and handle. They generate up to 10% PAA in situ when dissolved in water. A 0.2% aqueous solution of Bioxy (equivalent to 200 ppm PAA) effected a 6.76 log reduction in Methicillin-resistant Staphylococcus aureus (MRSA) within 2 minutes after application. A 5% aqueous solution of Bioxy achieved a 3.93 log reduction in the bovine tuberculosis bacillus

  7. Contamination profiles of antifouling biocides in selected coastal regions of Malaysia.

    PubMed

    Harino, Hiroya; Arai, Takaomi; Ohji, Madoka; Ismail, Ahmad Bin; Miyazaki, Nobuyuki

    2009-04-01

    The concentrations of butyltins (BTs) in sediment from Peninsular Malaysia along the Strait of Malacca and their spatial distribution are discussed. The concentrations of BTs were high in the southern part of Peninsular Malaysia where there is a lot of ship traffic, because trade is prosperous. The concentrations of monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) in sediment from the coastal waters of Peninsular Malaysia were in the range 4.1-242 microg/kg dry weight (dw), 1.1-186 microg/kg dw, and 0.7-228 microg/kg dw, respectively. A higher percentage of TBT was observed in the area where TBT concentrations were high. The concentrations of monophenyltin (MPT), diphenyltin (DPT), and triphenyltin (TPT) were in the range <0.1-121 microg/kg dw, 0.4-27 microg/kg dw, and 0.1-34 microg/kg dw in sediment from Peninsular Malaysia, respectively. MPT was the dominant phenyltin species. MBT, DBT, and TBT in green mussel (Perna viridis) samples were detected in the range 41-102 microg/kg, 3-5 microg/kg, and 8-32 microg/kg, respectively. A tolerable average residue level (TARL) was estimated at 20.4 microg/kg from a tolerable daily intake (TDI) of 0.25 microg TBTO/kg body weight/day. The maximum value of TBT detected in green mussel samples was the value near the TARL. TPTs were not detected in green mussel samples. The concentrations of Diuron and Irgarol 1051 in sediment from Peninsular Malaysia were in the range <0.1-5 microg/kg dw and <0.1-14 microg/kg dw, respectively. High concentrations of these compounds were observed in locations where the concentrations of TBT were high. Sea Nine 211, Dichlofluanid, and Pyrithiones were not detected in sediment. The concentrations of antifouling biocides in Melaka and the Strait of Johor were investigated in detail. BTs were found in similar concentrations among all sampling sites from Melaka, indicating that BT contamination spread off the coast. However, Sea Nine 211, Diuron, and Irgarol 1051 in the sediment from

  8. Effect of size of Fe3O4 magnetic nanoparticles on electrochemical performance of screen printed electrode using sedimentation field-flow fractionation

    NASA Astrophysics Data System (ADS)

    Dou, Haiyang; Kim, Beom-Ju; Choi, Seong-Ho; Jung, Euo Chang; Lee, Seungho

    2014-10-01

    Fe3O4 magnetic nanoparticles (MNPs) and Fe3O4-deposited multi-walled carbon nanotubes (Fe3O4@MWCNTs) were synthesized by ultrasonic co-precipitation method. The surface and structural properties of Fe3O4 MNPs and Fe3O4@MWCNTs were characterized by X-ray diffraction, field emission transmission electron microscopy (FE-TEM), X-ray photoelectron spectroscopy, and dynamic light scattering (DLS). Sedimentation field-flow fractionation (SdFFF) was, for the first time, employed to study the influence of synthesis parameters on size distribution of Fe3O4 MNPs. A reasonable resolution for SdFFF analysis of Fe3O4 MNPs was obtained by a combination of 1,600 RPM, flow rate of 0.3 mL min-1, and Triton X-100. The results suggest that lower pH and higher reaction temperature tend to yield smaller Fe3O4 MNPs size. The size distribution of Fe3O4 MNPs obtained from SdFFF was compared with those obtained from TEM and DLS. Also the effect of the particle size of Fe3O4 MNPs on electrochemical property of Fe3O4@MWCNTs-treated screen printed electrode (SPE) was studied. Cyclic voltammetry revealed that SPE treated with MWCNTs yields a significantly enhanced signal than that with no treatment. The SPE signal was even further enhanced with addition of Fe3O4 MNPs. For SPE analysis of dopamine, a liner range of 0.005-0.1 mM with a correlation coefficient of 0.986 was observed. Results revealed that (1) SdFFF is a useful tool for size-based separation and characterization of MNPs; (2) Proposed methods for synthesis of Fe3O4 nanoparticles and Fe3O4@MWCNTs are mild and fast (about 30 min); (3) SPE treated with Fe3O4@MWCNTs shows potential applicability for biosensing.

  9. Health Screening

    MedlinePlus

    Screenings are tests that look for diseases before you have symptoms. Screening tests can find diseases early, when they're easier ... Overweight and obesity Prostate cancer in men Which tests you need depends on your age, your sex, ...

  10. Depression Screening

    MedlinePlus

    ... Centers Diseases + Condition Centers Mental Health Medical Library Depression Screening (PHQ-9) - Instructions The following questions are ... this tool, there is also text-only version . Depression Screening - Manual Instructions The following questions are a ...

  11. Antimicrobial Efficacy of a Novel Eucalyptus Oil, Chlorhexidine Digluconate and Isopropyl Alcohol Biocide Formulation

    PubMed Central

    Hendry, Emma; Conway, Barbara; Worthington, Tony

    2012-01-01

    Effective surface disinfection is a fundamental infection control strategy within healthcare. This study assessed the antimicrobial efficacy of novel biocide formulations comprising 5% and 2% eucalyptus oil (EO) combined with 2% chlorhexidine digluconate (CHG) and 70% isopropyl alcohol (IPA) contained within a wipe. The efficacy of this novel antimicrobial formulation to remove and eliminate methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli and Candida albicans from steel surfaces was investigated. Adpression studies of pre-contaminated wipes were also utilised to assess their potential to induce cross-contamination between hard surfaces. Furthermore, the bactericidal nature of the EO-formulation was established in addition to time-kill. The EO-containing formulations demonstrated bactericidal antimicrobial efficacy against all microorganisms and did not induce surface cross-contamination. There was no significant difference (p < 0.05) between the 5% and 2% EO formulations in their ability to remove microorganisms from steel surfaces, however both significantly (p < 0.05) removed more than the control formulations. Microbial biofilms were eliminated within 10 min (p < 0.05) when exposed to the EO formulations. Our novel EO-formulation demonstrated rapid antimicrobial efficacy for potential disinfection and elimination of microbial biofilms from hard surfaces and may therefore be a useful adjunct to current infection control strategies currently employed within healthcare facilities. PMID:23203047

  12. Determination and levels of the biocide ortho-phenylphenol in canned beers from different countries.

    PubMed

    Coelhan, Mehmet; Bromig, Karl-Heinz; Glas, Karl; Roberts, A Lynn

    2006-08-09

    A method was developed for the determination of the biocide ortho-phenylphenol (biphenyl-2-ol; OPP) in beer, using deuterated OPP as an internal standard. A new liquid-liquid extraction procedure, employing acetonitrile, diethyl ether, and n-pentane, afforded rapid phase separation. The evaporated extract was derivatized with pentafluorobenzyl bromide in a water-acetonitrile mixture that was buffered with potassium carbonate, followed by extraction of the derivative into cyclohexane and analysis by gas chromatography-mass spectrometry in electron ionization mode. The method enables the detection of OPP in 50 mL of beer at concentrations as low as 0.1 microg/L and provides a linear range of quantification of 0.5-40 microg/L. Samples from 61 beers canned over the past 12 years and sold in 27 countries were analyzed for OPP. In 40 of them, the target compound was present at concentrations of 1.2-40 microg/L. Our investigations indicate that the ends of the cans, which contain sealing material presumably treated with OPP, are responsible for this contamination.

  13. Biocide activity of Annona coriacea seeds extract on Rhodnius neglectus (Hemiptera: Reduviidae).

    PubMed

    Carneirol, Angela Pinheiro; Pereira, Mônica Josene Barbosa; Galbiati, Carla

    2013-03-01

    The use of synthetic insecticides for insect control may lead to different kind of problems, such as vector resistance to insecticides. To avoid these problems, a new research area to study botanical products as possible disease vectors controls, has become a feasible alternative. The purpose of this research was to evaluate the biocide activity of the ethanol extract of seeds of Annona coriacea on Rhodnius neglectus (Chagas disease vector) nymphs and adults. For this, different concentrations extracts were evaluated: 25, 50, 100 and 200mg/ mL, and water in DMSO (20%) was used as control. The experimental design was completely randomized and we conducted the bioassay with nymphs and adults, with 10 nymphs and 10 adults (five males and five females) per treatment. Extract action was evaluated in both bioassays, in order to identify possible effects of mortality and life cycle interruption of nymphs and adults during a 28-day-period. The results obtained showed that the extract of A. coriacea was able to disrupt the development of nymphs and adults of R. neglectus, with a mortality rate of more than 90%, 36% and 100%, at the highest concentrations, respectively. There was also molting inhibition in nymphs, lower reproductive capacity in females, feeding deterrence and morphological changes in nymphs and adults. We concluded that the extract of A. coriacea has insecticide action on nymphs and adults of R. neglectus.

  14. Essential Oils of Plants as Biocides against Microorganisms Isolated from Cuban and Argentine Documentary Heritage.

    PubMed

    Borrego, Sofía; Valdés, Oderlaise; Vivar, Isbel; Lavin, Paola; Guiamet, Patricia; Battistoni, Patricia; Gómez de Saravia, Sandra; Borges, Pedro

    2012-01-01

    Natural products obtained from plants with biocidal activity represent an alternative and useful source in the control of biodeterioration of documentary heritage, without negative environmental and human impacts. In this work, we studied the antimicrobial activity of seven essential oils against microorganisms associated with the biodeterioration of documentary heritage. The essential oils were obtained by steam distillation. The antimicrobial activity was analyzed using the agar diffusion method against 4 strains of fungi and 6 bacterial strains isolated from repositories air and documents of the National Archive of the Republic of Cuba and the Historical Archive of the Museum of La Plata, Argentina. Anise and garlic oils showed the best antifungal activity at all concentrations studied, while oregano oil not only was effective against fungi tested but also prevented sporulation of them all. Orange sweet and laurel oils were ineffective against fungi. Clove, garlic, and oregano oils showed the highest antibacterial activity at 25% against Enterobacter agglomerans and Streptomyces sp., while only clove and oregano oils were effective against Bacillus sp. at all concentrations studied. This study has an important implication for the possible use of the natural products from plants in the control of biodeterioration of documentary heritage.

  15. Mechanical performance of a biocompatible biocide soda-lime glass-ceramic.

    PubMed

    López-Esteban, S; Bartolomé, J F; Dí Az, L A; Esteban-Tejeda, L; Prado, C; López-Piriz, R; Torrecillas, R; Moya, J S

    2014-06-01

    A biocompatible soda-lime glass-ceramic in the SiO2-Na2O-Al2O3-CaO-B2O3 system containing combeite and nepheline as crystalline phases, has been obtained at 750°C by two different routes: (i) pressureless sintering and (ii) Spark Plasma Sintering. The SPS glass-ceramic showed a bending strength, Weibull modulus, and toughness similar values to the cortical human bone. This material had a fatigue limit slightly superior to cortical bone and at least two times higher than commercial dental glass-ceramics and dentine. The in vitro studies indicate that soda-lime glass-ceramic is fully biocompatible. The in vivo studies in beagle jaws showed that implanted SPS rods presented no inflammatory changes in soft tissues surrounding implants in any of the 10 different cases after four months implantation. The radiological analysis indicates no signs of osseointegration lack around implants. Moreover, the biocide activity of SPS glass-ceramic versus Escherichia coli, was found to be >4log indicating that it prevents implant infections. Because of this, the SPS new glass-ceramic is particularly promising for dental applications (inlay, crowns, etc).

  16. [Determination of three isothiazolinone biocides in water-borne adhesives by high performance liquid chromatography].

    PubMed

    Zhou, Xiao; Li, Xiaolan; Chen, Zhiyan; Ye, Changwen; Zhou, Yun; Meng, Dongling

    2015-01-01

    A rapid high performance liquid chromatography (HPLC) method was developed for the quantitative analysis of three isothiazolinone biocides (2-methyl-4-isothiazolin-3-one (MI), 5-chloro-2-methyl-4-isothiazolin-3-one (CMI) and 1, 2-benzylisothiazolin-3-one (BIT)) in water-borne adhesives. The sample was extracted with methanol-water (1:1, v/v), and purified by centrifugation and filtration. The isothiazolones were separated on a C18 column with methanol-water as mobile phases under gradient elution and detected with a diode array detector (DAD). The pretreatment factors such as extraction solvent, extraction method, dilution ratio, extraction time were optimized. Under the optimized conditions, the targets had good linearities (r2H > or = 0.9992) in the range of 0.25-10.0 mg/L. The recoveries were between 92% and 103% with the relative standard deviations not more than 4%. The limits of detection (LODs) were between 0.43 mg/kg and 1.14 mg/kg. The limits of quantification (LOQs) were between 1.44 mg/kg and 3.81 mg/kg. The results showed that the method can achieve the purpose of quantitative detection. The analyses of real samples verified the reliability of this method.

  17. Putting copper into action: copper-impregnated products with potent biocidal activities.

    PubMed

    Borkow, Gadi; Gabbay, Jeffrey

    2004-11-01

    Copper ions, either alone or in copper complexes, have been used for centuries to disinfect liquids, solids, and human tissue. Today copper is used as a water purifier, algaecide, fungicide, nematocide, molluscicide, and antibacterial and antifouling agent. Copper also displays potent antiviral activity. We hypothesized that introducing copper into clothing, bedding, and other articles would provide them with biocidal properties. A durable platform technology has been developed that introduces copper into cotton fibers, latex, and other polymeric materials. This study demonstrates the broad-spectrum antimicrobial (antibacterial, antiviral, antifungal) and antimite activities of copper-impregnated fibers and polyester products. This technology enabled the production of antiviral gloves and filters (which deactivate HIV-1 and other viruses), antibacterial self-sterilizing fabrics (which kill antibiotic-resistant bacteria, including methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococci), antifungal socks (which alleviate symptoms of athlete's foot), and anti-dust mite mattress covers (which reduce mite-related allergies). These products did not have skin-sensitizing properties, as determined by guine pig maximization and rabbit skin irritation tests. Our study demonstrates the potential use of copper in new applications. These applications address medical issues of the greatest importance, such as viral transmissions; nosocomial, or healthcare-associated, infections; and the spread of antibiotic-resistant bacteria.

  18. Relation between Intensity of Biocide Practice and Residues of Anticoagulant Rodenticides in Red Foxes (Vulpes vulpes)

    PubMed Central

    Geduhn, Anke; Jacob, Jens; Schenke, Detlef; Keller, Barbara; Kleinschmidt, Sven; Esther, Alexandra

    2015-01-01

    Anticoagulant rodenticides (ARs) are commonly used to control rodent infestations for biocidal and plant protection purposes. This can lead to AR exposure of non-target small mammals and their predators, which is known from several regions of the world. However, drivers of exposure variation are usually not known. To identify environmental drivers of AR exposure in non-targets we analyzed 331 liver samples of red foxes (Vulpes vulpes) for residues of eight ARs and used local parameters (percentage of urban area and livestock density) to test for associations to residue occurrence. 59.8% of samples collected across Germany contained at least one rodenticide, in 20.2% of cases at levels at which biological effects are suspected. Second generation anticoagulants (mainly brodifacoum and bromadiolone) occurred more often than first generation anticoagulants. Local livestock density and the percentage of urban area were good indicators for AR residue occurrence. There was a positive association between pooled ARs and brodifacoum occurrence with livestock density as well as of pooled ARs, brodifacoum and difenacoum occurrence with the percentage of urban area on administrative district level. Pig holding drove associations of livestock density to AR residue occurrence in foxes. Therefore, risk mitigation strategies should focus on areas of high pig density and on highly urbanized areas to minimize non-target risk. PMID:26418154

  19. Effects of the biocide methylisothiazolinone on Xenopus laevis wound healing and tail regeneration.

    PubMed

    Delos Santos, Nicole; Azmat, Summer; Cuenca, Yesenia; Drenth, Jessica; Lauper, Julia; Tseng, Ai-Sun

    2016-12-01

    The South African clawed frog, Xenopus laevis, has a strong history as a suitable model for environmental studies. Its embryos and transparent tadpoles are highly sensitive to the environment and their developmental processes are well described. It is also amenable for molecular studies. These characteristics enable its use for rapid identification and understanding of exposure-induced defects. To investigate the consequences of chemical exposure on aquatic animals, Xenopus laevis embryos and tadpoles were exposed to the biocide, methylisothiazolinone (MIT). Frog tadpoles exposed to MIT following tail amputation lost their natural regenerative ability. This inhibition of regeneration led to a failure to regrow tissues including the spinal cord, muscle, and notochord. This MIT-dependent regenerative defect is due to a failure to close the amputation wound. A wound healing assay revealed that while untreated embryos close their wounds within one day after injury, MIT-treated animals maintained open wounds that did not reduce in size and caused lethality. Concomitant exposure of MIT with chemicals containing thiol groups such as glutathione and N-acetyl cysteine restored normal wound healing and regeneration responses in tadpoles. Together these results indicate that exposure to MIT impairs developmental wound repair and tissue regeneration in Xenopus laevis. Thus, this study reveals new aspects of MIT activity and demonstrates that Xenopus laevis is a well-suited model for facilitating future research into chemical exposure effects on injury responses.

  20. Relation between Intensity of Biocide Practice and Residues of Anticoagulant Rodenticides in Red Foxes (Vulpes vulpes).

    PubMed

    Geduhn, Anke; Jacob, Jens; Schenke, Detlef; Keller, Barbara; Kleinschmidt, Sven; Esther, Alexandra

    2015-01-01

    Anticoagulant rodenticides (ARs) are commonly used to control rodent infestations for biocidal and plant protection purposes. This can lead to AR exposure of non-target small mammals and their predators, which is known from several regions of the world. However, drivers of exposure variation are usually not known. To identify environmental drivers of AR exposure in non-targets we analyzed 331 liver samples of red foxes (Vulpes vulpes) for residues of eight ARs and used local parameters (percentage of urban area and livestock density) to test for associations to residue occurrence. 59.8% of samples collected across Germany contained at least one rodenticide, in 20.2% of cases at levels at which biological effects are suspected. Second generation anticoagulants (mainly brodifacoum and bromadiolone) occurred more often than first generation anticoagulants. Local livestock density and the percentage of urban area were good indicators for AR residue occurrence. There was a positive association between pooled ARs and brodifacoum occurrence with livestock density as well as of pooled ARs, brodifacoum and difenacoum occurrence with the percentage of urban area on administrative district level. Pig holding drove associations of livestock density to AR residue occurrence in foxes. Therefore, risk mitigation strategies should focus on areas of high pig density and on highly urbanized areas to minimize non-target risk.

  1. Designing a biocidal reverse osmosis membrane coating: Synthesis and biofouling properties

    SciTech Connect

    Hibbs, Michael R.; McGrath, Lucas K.; Kang, Seoktae; Adout, Atar; Altman, Susan J.; Elimelech, Menachem; Cornelius, Chris J.

    2015-12-04

    In this study, a biocidal coating was developed in order to reduce biofouling on a reverse osmosis (RO) membrane using a quaternary ammonium (QA) functionalized polymer. The synthesis of a series of polysulfone (PS) ionomers with QA groups is described, and a method for spraying these QA ionomers as an alcoholic solution, which dried into water insoluble coatings. Contact angle and streaming potential were used to analyze the coating's hydrophilicity and surface charge. Both PS-QA1 and the commercial RO membrane had an apparent contact angle of 68° that increased to 126° for PS-QA12 corresponding to alkyl chain length. A negatively charged particle-probe was used to measure coated and uncoated RO membrane interaction forces. Measured interaction forces correlated strongly with the length of alkyl chains or hydrophobicity of the coated surfaces. Uncoated RO membranes and ones coated with PS-QA were exposed to suspensions of Escherichia coli cells. All four PS-QA coatings showed significant biotoxicity and killed 100% of the E. coli cells, but uncoated RO membranes had metabolically active biofilms. However, coatings tested in a RO crossflow system showed a flux reduction that is attributed to mass transfer resistance due to excessively thick films.

  2. Designing a biocidal reverse osmosis membrane coating: Synthesis and biofouling properties

    DOE PAGES

    Hibbs, Michael R.; McGrath, Lucas K.; Kang, Seoktae; ...

    2015-12-04

    In this study, a biocidal coating was developed in order to reduce biofouling on a reverse osmosis (RO) membrane using a quaternary ammonium (QA) functionalized polymer. The synthesis of a series of polysulfone (PS) ionomers with QA groups is described, and a method for spraying these QA ionomers as an alcoholic solution, which dried into water insoluble coatings. Contact angle and streaming potential were used to analyze the coating's hydrophilicity and surface charge. Both PS-QA1 and the commercial RO membrane had an apparent contact angle of 68° that increased to 126° for PS-QA12 corresponding to alkyl chain length. A negativelymore » charged particle-probe was used to measure coated and uncoated RO membrane interaction forces. Measured interaction forces correlated strongly with the length of alkyl chains or hydrophobicity of the coated surfaces. Uncoated RO membranes and ones coated with PS-QA were exposed to suspensions of Escherichia coli cells. All four PS-QA coatings showed significant biotoxicity and killed 100% of the E. coli cells, but uncoated RO membranes had metabolically active biofilms. However, coatings tested in a RO crossflow system showed a flux reduction that is attributed to mass transfer resistance due to excessively thick films.« less

  3. Essential Oils of Plants as Biocides against Microorganisms Isolated from Cuban and Argentine Documentary Heritage

    PubMed Central

    Borrego, Sofía; Valdés, Oderlaise; Vivar, Isbel; Lavin, Paola; Guiamet, Patricia; Battistoni, Patricia; Gómez de Saravia, Sandra; Borges, Pedro

    2012-01-01

    Natural products obtained from plants with biocidal activity represent an alternative and useful source in the control of biodeterioration of documentary heritage, without negative environmental and human impacts. In this work, we studied the antimicrobial activity of seven essential oils against microorganisms associated with the biodeterioration of documentary heritage. The essential oils were obtained by steam distillation. The antimicrobial activity was analyzed using the agar diffusion method against 4 strains of fungi and 6 bacterial strains isolated from repositories air and documents of the National Archive of the Republic of Cuba and the Historical Archive of the Museum of La Plata, Argentina. Anise and garlic oils showed the best antifungal activity at all concentrations studied, while oregano oil not only was effective against fungi tested but also prevented sporulation of them all. Orange sweet and laurel oils were ineffective against fungi. Clove, garlic, and oregano oils showed the highest antibacterial activity at 25% against Enterobacter agglomerans and Streptomyces sp., while only clove and oregano oils were effective against Bacillus sp. at all concentrations studied. This study has an important implication for the possible use of the natural products from plants in the control of biodeterioration of documentary heritage. PMID:23762760

  4. A Metric for Reducing False Positives in the Computer-Aided Detection of Breast Cancer from Dynamic Contrast-Enhanced Magnetic Resonance Imaging Based Screening Examinations of High-Risk Women.

    PubMed

    Levman, Jacob E D; Gallego-Ortiz, Cristina; Warner, Ellen; Causer, Petrina; Martel, Anne L

    2016-02-01

    Magnetic resonance imaging (MRI)-enabled cancer screening has been shown to be a highly sensitive method for the early detection of breast cancer. Computer-aided detection systems have the potential to improve the screening process by standardizing radiologists to a high level of diagnostic accuracy. This retrospective study was approved by the institutional review board of Sunnybrook Health Sciences Centre. This study compares the performance of a proposed method for computer-aided detection (based on the second-order spatial derivative of the relative signal intensity) with the signal enhancement ratio (SER) on MRI-based breast screening examinations. Comparison is performed using receiver operating characteristic (ROC) curve analysis as well as free-response receiver operating characteristic (FROC) curve analysis. A modified computer-aided detection system combining the proposed approach with the SER method is also presented. The proposed method provides improvements in the rates of false positive markings over the SER method in the detection of breast cancer (as assessed by FROC analysis). The modified computer-aided detection system that incorporates both the proposed method and the SER method yields ROC results equal to that produced by SER while simultaneously providing improvements over the SER method in terms of false positives per noncancerous exam. The proposed method for identifying malignancies outperforms the SER method in terms of false positives on a challenging dataset containing many small lesions and may play a useful role in breast cancer screening by MRI as part of a computer-aided detection system.

  5. Use of 5-Cyano-2,3-Ditolyl-Tetrazolium Chloride Staining as an Indicator of Biocidal Activity in a Rapid Assay for Anti-Acanthamoeba Agents

    PubMed Central

    Kobayashi, Takeshi; Mito, Tsuyoshi; Watanabe, Narumi; Suzuki, Takashi; Ohashi, Yuichi

    2012-01-01

    The usefulness of 5-cyano-2,3-ditolyl-tetrazolium chloride (CTC) staining to determine the respiratory activity of Acanthamoeba was evaluated in this study. Acanthamoeba trophozoites and cysts have a red fluorescence after staining with CTC. To determine the effectiveness of CTC staining as a CTC biocidal assay for Acanthamoeba, the trophozoites and cysts of Acanthamoeba castellanii (ATCC 5037) were treated with serial concentrations of disinfectant solutions, namely, polyhexamethylene biguanide (PHMB) and commercial soft contact lens (SCL) disinfectant solutions. The treated Acanthamoeba organisms were stained with CTC, and their respiratory activity was determined by the intensity of fluorescence in a fluorescence microplate reader. The survival rates of the same samples were determined by a culture-dependent biocidal assay using the Spearman-Karber method. Our results showed that the respiratory activities determined by the CTC biocidal assay and the survival rates determined by the culture-dependent biocidal assay for Acanthamoeba trophozoites and cysts decreased in a dose-dependent way after PHMB treatments, and the results were significantly correlated (r = 0.83 and P < 0.01 for trophozoites; r = 0.60 and P < 0.01 for cysts; Spearman rank correlation test). The respiratory activities in the trophozoites and cysts treated with SCL disinfectant solutions were significantly correlated with the survival rate (r = 0.70 and P < 0.01 for trophozoites; r = 0.64 and P < 0.01 for cysts; Spearman rank correlation test). The significant correlation of the results indicated that the CTC biocidal assay can be used as an alternative method to a culture-dependent biocidal assay. The CTC biocidal assay is a rapid and simple method to test the effectiveness of disinfectant solutions against Acanthamoeba trophozoites and cysts. PMID:22337974

  6. Double screening

    SciTech Connect

    Gratia, Pierre; Hu, Wayne; Joyce, Austin; Ribeiro, Raquel H.

    2016-06-15

    Attempts to modify gravity in the infrared typically require a screening mechanism to ensure consistency with local tests of gravity. These screening mechanisms fit into three broad classes; we investigate theories which are capable of exhibiting more than one type of screening. Specifically, we focus on a simple model which exhibits both Vainshtein and kinetic screening. We point out that due to the two characteristic length scales in the problem, the type of screening that dominates depends on the mass of the sourcing object, allowing for different phenomenology at different scales. We consider embedding this double screening phenomenology in a broader cosmological scenario and show that the simplest examples that exhibit double screening are radiatively stable.

  7. Colon cancer screening

    MedlinePlus

    Screening for colon cancer; Colonoscopy - screening; Sigmoidoscopy - screening; Virtual colonoscopy - screening; Fecal immunochemical test; Stool DNA test; sDNA test; Colorectal cancer - screening; Rectal ...

  8. Pesticides and biocides in a karst catchment: Identification of contaminant sources and related flow components

    NASA Astrophysics Data System (ADS)

    Wagner, Thomas; Bollmann, Ulla E.; Bester, Kai; Birk, Steffen

    2013-04-01

    Karst aquifers are widely used as drinking water resources. However, their high vulnerability to chemical and bacterial contamination due to the heterogeneity in aquifer properties (highly conductive solution conduits embedded in the less conductive fissured rock) is difficult to assess and thus poses major challenges to the management of karst water resources. Contamination of karst springs by organic micro-pollutants has been observed in recent studies. Within this study the water from different springs draining one karst aquifer as well as the main sinking stream replenishing it were analysed before, during and after a storm water event in order to examine the occurrence of different pesticides and biocides. Contaminants from both urban as well as agricultural origin could be detected in the water with concentrations in the low ng/L range (tebuconazole, carbendazim, diuron, isoproturon, terbutryn, atrazine, dichlorobenzamide (BAM), which is a metabolite of dichlobenil). While some compounds could be followed from the sinking stream to the springs (e.g. dichlorobenzamide) some seem to have a source in the autogenic recharge from the karst plateau (Tebuconazole: wood preservative in buildings). These compounds appear to be related to fast flow components with residence times in the order of days, which are known from a number of tracer tests with fluorescent dyes. However, the occurrence of the pesticide atrazine (banned since 1995 in Austria) in the springs, while on the other hand no current input into the karst occurs, shows that some compounds have long residence times in the karst aquifer. These differences in residence times can hardly be attributed to differences in physico-chemical properties of the compounds and must thus be due to the presence of slow and fast flow components. This is in agreement with the duality of karst aquifers due to highly conductive networks of solution conduits embedded in less conductive fissured carbonate rocks.

  9. Features of microbiological behavior and biocide properties of electrosynthesized polymethylolacrylamide films

    NASA Astrophysics Data System (ADS)

    Kolzunova, Lidia G.

    2016-05-01

    The biocide properties of an electrosynthesized of acrylamide, N,N'-methylene-bis-acrylamide and formaldehyde copolymer films against the Staphylococcus aureus and bacterial association extracted from seawater (marine biological organisms) were investigated. Copolymer films were stable in organic solvents, acids and alkali and insoluble in water, though capable to swelling ability. Besides, the polymer is thermally stable up to 237°C. It was established that the anti-bacterial effect of the films started to be expressed after two days and was maintained from 2 up to 45 days. It was established that the degree of polymer films toxicity depended on the polymer synthesis conditions, pre-treatment method and duration of the biological object exposure to the effect. It was shown that antiseptic properties of the polymer material under study were imparted by formaldehyde both as sorbed by the polymer and as included into the copolymer composition. The toxicological effect of the polymethylolacrylamide films under study on microorganisms can be applied as in medicine (antiseptic materials and implants) as for equipment protection from bio-fouling and bio-corrosion. Microbiological stability and sterilizing effect of electrosynthesized polymethylolacrylamide ultrafiltration membranes enables one not only to prolong the operation time of film membranes, but also to provide partial sterilization of organic solutions to be filtered. It was established that polymer waste can be utilized by means of microbial destruction. It was found that the washed out polymer induced a specific bacteria behavior consisting of a complex of reactions directed to search, capture and consume nutrients.

  10. International Space Station (ISS) Internal Active Thermal Control System (IATCS) New Biocide Selection, Qualification and Implementation

    NASA Technical Reports Server (NTRS)

    Wilson, Mark E.; Cole, Harold; Rector, Tony; Steele, John; Varsik, Jerry

    2010-01-01

    The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) is primarily responsible for the removal of heat loads from payload and system racks. The IATCS is a water based system which works in conjunction with the EATCS (External ATCS), an ammonia based system, which are interfaced through a heat exchanger to facilitate heat transfer. On-orbit issues associated with the aqueous coolant chemistry began to occur with unexpected increases in CO2 levels in the cabin. This caused an increase in total inorganic carbon (TIC), a reduction in coolant pH, increased corrosion, and precipitation of nickel phosphate. These chemical changes were also accompanied by the growth of heterotrophic bacteria that increased risk to the system and could potentially impact crew health and safety. Studies were conducted to select a biocide to control microbial growth in the system based on requirements for disinfection at low chemical concentration (effectiveness), solubility and stability, material compatibility, low toxicity to humans, compatibility with vehicle environmental control and life support systems (ECLSS), ease of application, rapid on-orbit measurement, and removal capability. Based on these requirements, ortho-phthalaldehyde (OPA), an aromatic dialdehyde compound, was selected for qualification testing. This paper presents the OPA qualification test results, development of hardware and methodology to safely apply OPA to the system, development of a means to remove OPA, development of a rapid colorimetric test for measurement of OPA, and the OPA on-orbit performance for controlling the growth of microorganisms in the ISS IATCS since November 3, 2007.

  11. International Space Station (ISS) Internal Active Thermal Control System (IATCS) New Biocide Selection, Qualification and Implementation

    NASA Technical Reports Server (NTRS)

    Wilson, Mark E.; Cole, Harold E.; Rector, Tony; Steele, John; Varsik, Jerry

    2011-01-01

    The Internal Active Thermal Control System (IATCS) aboard the International Space Station (ISS) is primarily responsible for the removal of heat loads from payload and system racks. The IATCS is a water based system which works in conjunction with the EATCS (External ATCS), an ammonia based system, which are interfaced through a heat exchanger to facilitate heat transfer. On-orbit issues associated with the aqueous coolant chemistry began to occur with unexpected increases in CO2 levels in the cabin. This caused an increase in total inorganic carbon (TIC), a reduction in coolant pH, increased corrosion, and precipitation of nickel phosphate. These chemical changes were also accompanied by the growth of heterotrophic bacteria that increased risk to the system and could potentially impact crew health and safety. Studies were conducted to select a biocide to control microbial growth in the system based on requirements for disinfection at low chemical concentration (effectiveness), solubility and stability, material compatibility, low toxicity to humans, compatibility with vehicle environmental control and life support systems (ECLSS), ease of application, rapid on-orbit measurement, and removal capability. Based on these requirements, ortho-phthalaldehyde (OPA), an aromatic dialdehyde compound, was selected for qualification testing. This paper presents the OPA qualification test results, development of hardware and methodology to safely apply OPA to the system, development of a means to remove OPA, development of a rapid colorimetric test for measurement of OPA, and the OPA on-orbit performance for controlling the growth of microorganisms in the ISS IATCS since November 3, 2007.

  12. Biocidal Efficacy of Copper Alloys against Pathogenic Enterococci Involves Degradation of Genomic and Plasmid DNAs ▿

    PubMed Central

    Warnes, S. L.; Green, S. M.; Michels, H. T.; Keevil, C. W.

    2010-01-01

    The increasing incidence of nosocomial infections caused by glycopeptide-resistant enterococci is a global concern. Enterococcal species are also difficult to eradicate with existing cleaning regimens; they can survive for long periods on surfaces, thus contributing to cases of reinfection and spread of antibiotic-resistant strains. We have investigated the potential use of copper alloys as bactericidal surfaces. Clinical isolates of vancomycin-resistant Enterococcus faecalis and Enterococcus faecium were inoculated onto copper alloy and stainless steel surfaces. Samples were assessed for the presence of viable cells by conventional culture, detection of actively respiring cells, and assessment of cell membrane integrity. Both species survived for up to several weeks on stainless steel. However, no viable cells were detected on any alloys following exposure for 1 h at an inoculum concentration of ≤104 CFU/cm2. Analysis of genomic and plasmid DNA from bacterial cells recovered from metal surfaces indicates substantial disintegration of the DNA following exposure to copper surfaces that is not evident in cells recovered from stainless steel. The DNA fragmentation is so extensive, and coupled with the rapid cell death which occurs on copper surfaces, that it suggests that mutation is less likely to occur. It is therefore highly unlikely that genetic information can be transferred to receptive organisms recontaminating the same area. A combination of effective cleaning regimens and contact surfaces containing copper could be useful not only to prevent the spread of viable pathogenic enterococci but also to mitigate against the occurrence of potential resistance to copper, biocides, or antibiotics and the spread of genetic determinants of resistance to other species. PMID:20581191

  13. Biocidal activity of metalloacid-coated surfaces against multidrug-resistant microorganisms

    PubMed Central

    2012-01-01

    Background The antimicrobial effects of a coating of molybdenum trioxide (MoO3) has been recently described. The metalloacid material produces oxonium ions (H3O+), which creates an acidic pH that is an effective, non specific antimicrobial. We determined the in vitro antimicrobial activity of molybdenum trioxide metalloacid-coated surfaces. Methods Metalloacid-coated and non-coated (control) surfaces were contaminated by exposing them for 15 minutes to microbial suspensions containing 105 cfu/mL. Eleven microorganisms responsible for nosocomial infections were tested: two Staphylococcus aureus strains (the hetero-vancomycin intermediate MRSA Mu50 strain and a ST80-PVL-producing MRSA strain); a vancomycin-resistant vanA Enterococcus faecium strain; three extended-spectrum beta-lactamase-producing Enterobacteriaceae strains; a MBL-producing Pseudomonas aeruginosa strain; a multidrug-resistant Acinetobacter baumannii strain; a toxin-producing Clostridium difficile strain; and two fungi (Candida albicans and Aspergillus fumigatus). The assay tested the ability of the coated surfaces to kill microorganisms. Results Against all non-sporulating microorganisms tested, metalloacid-coated surfaces exhibited significant antimicrobial activity relative to that of the control surfaces within two to six hours after contact with the microorganisms (p < 0.001). Microorganism survival on the coated surfaces was greatly impaired, whereas microorganism survival on control surfaces remained substantial. Conclusions We suggest that, facing the continuing shedding of microorganisms in the vicinity of colonized or infected patients, the continuous biocidal effect of hydroxonium oxides against multidrug-resistant microorganisms may help limit environmental contamination between consecutive cleaning procedures. PMID:23148568

  14. Genetic relatedness, antimicrobial and biocide susceptibility comparative analysis of methicillin-resistant and -susceptible Staphylococcus pseudintermedius from Portugal.

    PubMed

    Couto, Natacha; Belas, Adriana; Couto, Isabel; Perreten, Vincent; Pomba, Constança

    2014-08-01

    Forty methicillin-resistant and -susceptible Staphylococcus pseudintermedius (MRSP and MSSP, respectively) from colonization and infection in dogs and cats were characterized for clonality, antimicrobial, and biocide susceptibility. MSSP were genetically more diverse than MRSP by multi-locus sequence typing and pulsed-field gel electrophoresis. Three different spa types (t06, t02, t05) and two SCCmec types (II-III and V) were detected in the MRSP isolates. All MRSP and two MSSP strains were multidrug-resistant. Several antibiotic resistance genes (mecA, blaZ, tet(M), tet(K), aac(6')-Ie-aph(2')-Ia, aph(3')-III, ant(6)-Ia, sat4, erm(B), lnu(A), dfr(G), and catp(C221)) were identified by microarray and double mutations in the gyrA and grlA genes and a single mutation in the rpoB gene were detected by sequence analysis. No differences were detected between MSSP and MRSP in the chlorhexidine acetate (CHA) minimum inhibitory concentrations (MICs). However, two MSSP had elevated MIC to triclosan (TCL) and one to benzalkonium chloride and ethidium bromide. One MSSP isolate harboured a qacA gene, while in another a qacB gene was detected. None of the isolates harboured the sh-fabI gene. Three of the biocide products studied had high bactericidal activity (Otodine(®), Clorexyderm Spot Gel(®), Dermocanis Piocure-M(®)), while Skingel(®) failed to achieve a five log reduction in the bacterial counting. S. pseudintermedius have become a serious therapeutic challenge in particular if methicillin- resistance and/or multidrug-resistance are involved. Biocides, like CHA and TCL, seem to be clinically effective and safe topical therapeutic options.

  15. A capillary liquid chromatography method for benzalkonium chloride determination as a component or contaminant in mixtures of biocides.

    PubMed

    Prieto-Blanco, M C; Argente-García, A; Campíns-Falcó, P

    2016-01-29

    A method for quantifying benzalkonium chloride (BAK), an alkyl dimethyl benzyl ammonium compound, in several biocides formulations is proposed. A tertiary amine like N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) and a straight-chain alkyl ammonium compound like trimethyl-tetradecyl ammonium chloride (TMTDAC), have been employed as trade surfactants besides BAK. Two capillary analytical columns with different polarities are tested: inertsil CN-3 capillary column (150mm×0.5mm i.d., 3μm particle diameter) and a non endcapped Zorbax C18 capillary column (35mm×0.5mm i.d., 5μm particle diameter). This latter column provided the best separation of the BAK homologues in less than 12min using acetonitrile:acetate buffer (50mM, pH 5) 85:15 at 20μLmin(-1). The proposed method combines on-line in-tube solid-phase microextraction (IT-SPME) coupled to capillary liquid chromatography (CapLC) and UV diode array detection. Matrix effect was present when TA were in excess to BAK. If TMTDAC is the co-biocide, matrix effect is always present. A decreasing of analytical response mainly for C12-BAK homologue was found using both chromatographic columns. The charged amount of mixture in the system was the most important parameter for obtaining reliable results. 1mL was the on line processed sample volume optimum for concentrations lower than 35μgmL(-1) of total surfactants. LODs were 0.03μgmL(-1) and 0.006μgmL(-1) for C12-BAK and C14-BAK, respectively. This method is also of use to evaluate the unwanted presence of BAK in biocide formulations due to industrial processes.

  16. Genetic screening

    PubMed Central

    Andermann, Anne; Blancquaert, Ingeborg

    2010-01-01

    Abstract OBJECTIVE To provide a primer for primary care professionals who are increasingly called upon to discuss the growing number of genetic screening services available and to help patients make informed decisions about whether to participate in genetic screening, how to interpret results, and which interventions are most appropriate. QUALITY OF EVIDENCE As part of a larger research program, a wide literature relating to genetic screening was reviewed. PubMed and Internet searches were conducted using broad search terms. Effort was also made to identify the gray literature. MAIN MESSAGE Genetic screening is a type of public health program that is systematically offered to a specified population of asymptomatic individuals with the aim of providing those identified as high risk with prevention, early treatment, or reproductive options. Ensuring an added benefit from screening, as compared with standard clinical care, and preventing unintended harms, such as undue anxiety or stigmatization, depends on the design and implementation of screening programs, including the recruitment methods, education and counseling provided, timing of screening, predictive value of tests, interventions available, and presence of oversight mechanisms and safeguards. There is therefore growing apprehension that economic interests might lead to a market-driven approach to introducing and expanding screening before program effectiveness, acceptability, and feasibility have been demonstrated. As with any medical intervention, there is a moral imperative for genetic screening to do more good than harm, not only from the perspective of individuals and families, but also for the target population and society as a whole. CONCLUSION Primary care professionals have an important role to play in helping their patients navigate the rapidly changing terrain of genetic screening services by informing them about the benefits and risks of new genetic and genomic technologies and empowering them to

  17. From Broad-Spectrum Biocides to Quorum Sensing Disruptors and Mussel Repellents: Antifouling Profile of Alkyl Triphenylphosphonium Salts

    PubMed Central

    Martín-Rodríguez, Alberto J.; Babarro, Jose M. F.; Lahoz, Fernando; Sansón, Marta; Martín, Víctor S.; Norte, Manuel; Fernández, José J.

    2015-01-01

    ‘Onium’ compounds, including ammonium and phosphonium salts, have been employed as antiseptics and disinfectants. These cationic biocides have been incorporated into multiple materials, principally to avoid bacterial attachment. In this work, we selected 20 alkyl-triphenylphosphonium salts, differing mainly in the length and functionalization of their alkyl chains, in fulfilment of two main objectives: 1) to provide a comprehensive evaluation of the antifouling profile of these molecules with relevant marine fouling organisms; and 2) to shed new light on their potential applications, beyond their classic use as broad-spectrum biocides. In this regard, we demonstrate for the first time that these compounds are also able to act as non-toxic quorum sensing disruptors in two different bacterial models (Chromobacterium violaceum and Vibrio harveyi) as well as repellents in the mussel Mytilus galloprovincialis. In addition, their inhibitory activity on a fouling-relevant enzymatic model (tyrosinase) is characterized. An analysis of the structure-activity relationships of these compounds for antifouling purposes is provided, which may result useful in the design of targeted antifouling solutions with these molecules. Altogether, the findings reported herein provide a different perspective on the biological activities of phosphonium compounds that is particularly focused on, but, as the reader will realize, is not limited to their use as antifouling agents. PMID:25897858

  18. From broad-spectrum biocides to quorum sensing disruptors and mussel repellents: antifouling profile of alkyl triphenylphosphonium salts.

    PubMed

    Martín-Rodríguez, Alberto J; Babarro, Jose M F; Lahoz, Fernando; Sansón, Marta; Martín, Víctor S; Norte, Manuel; Fernández, José J

    2015-01-01

    'Onium' compounds, including ammonium and phosphonium salts, have been employed as antiseptics and disinfectants. These cationic biocides have been incorporated into multiple materials, principally to avoid bacterial attachment. In this work, we selected 20 alkyl-triphenylphosphonium salts, differing mainly in the length and functionalization of their alkyl chains, in fulfilment of two main objectives: 1) to provide a comprehensive evaluation of the antifouling profile of these molecules with relevant marine fouling organisms; and 2) to shed new light on their potential applications, beyond their classic use as broad-spectrum biocides. In this regard, we demonstrate for the first time that these compounds are also able to act as non-toxic quorum sensing disruptors in two different bacterial models (Chromobacterium violaceum and Vibrio harveyi) as well as repellents in the mussel Mytilus galloprovincialis. In addition, their inhibitory activity on a fouling-relevant enzymatic model (tyrosinase) is characterized. An analysis of the structure-activity relationships of these compounds for antifouling purposes is provided, which may result useful in the design of targeted antifouling solutions with these molecules. Altogether, the findings reported herein provide a different perspective on the biological activities of phosphonium compounds that is particularly focused on, but, as the reader will realize, is not limited to their use as antifouling agents.

  19. Chlorine dioxide as an alternative antifouling biocide for cooling water systems: Toxicity to larval barnacle Amphibalanus reticulatus (Utinomi).

    PubMed

    Venkatnarayanan, Srinivas; Sriyutha Murthy, P; Kirubagaran, Ramalingam; Venugopalan, Vayalam P

    2017-01-19

    Chlorine dioxide (ClO2) is seen as an effective alternative to chlorine, which is widely used as an antifouling biocide. However, data on its efficacy against marine macrofoulants is scanty. In this study, acute toxicity of ClO2 to larval forms of the fouling barnacle Amphibalanus reticulatus was investigated. ClO2 treatment at 0.1mg/L for 20min elicited 45-63% reduction in naupliar metamorphosis, 70% inhibition of cyprid settlement and 80% inhibition of metamorphosis to juveniles. Increase in concentration to 0.2mg/L did not result in any significant difference in the settlement inhibition or metamorphosis. Treatment with 0.2mg/L of ClO2 elicited substantial reduction in the settlement of barnacle larvae compared to control. The study indicates the possibility of using ClO2 as an alternative antifouling biocide in power plant cooling water systems. However, more work needs to be done on the environmental effects of such switchover, which we are currently undertaking.

  20. The Biocide Chlorine Dioxide Stimulates Biofilm Formation in Bacillus subtilis by Activation of the Histidine Kinase KinC▿ †

    PubMed Central

    Shemesh, Moshe; Kolter, Roberto; Losick, Richard

    2010-01-01

    Bacillus subtilis forms biofilms in response to signals that remain poorly defined. We report that biofilm formation is stimulated by sublethal doses of chlorine dioxide (ClO2), an extremely effective and fast-acting biocide. ClO2 accelerated biofilm formation in B. subtilis as well as in other bacteria, suggesting that biofilm formation is a widely conserved response to sublethal doses of the agent. Biofilm formation depends on the synthesis of an extracellular matrix that holds the constituent cells together. We show that the transcription of the major operons responsible for the matrix production in B. subtilis, epsA-epsO and yqxM-sipW-tasA, was enhanced by ClO2, in a manner that depended on the membrane-bound kinase KinC. Activation of KinC appeared to be due to the ability of ClO2 to collapse the membrane potential. Importantly, strains unable to make a matrix were hypersensitive to ClO2, indicating that biofilm formation is a defensive response that helps protect cells from the toxic effects of the biocide. PMID:20971918

  1. Resistance of two temperate Lactobacillus paracasei bacteriophages to high pressure homogenization, thermal treatments and chemical biocides of industrial application.

    PubMed

    Mercanti, D J; Guglielmotti, D M; Patrignani, F; Reinheimer, J A; Quiberoni, A

    2012-02-01

    Temperate bacteriophages ф iLp84 and ф iLp1308, previously isolated from mitomycin C-induction of Lactobacillus paracasei strains 84 and CNRZ1308, respectively, were tested for their resistance to several physical and chemical treatments applied in dairy industry. Long-term survival at 4 °C, -20 °C and -80 °C, resistance to either thermal treatments of 63 °C, 72 °C and 90 °C, high pressure homogenization (HPH, 100 MPa) or classic (ethanol, sodium hypochlorite and peracetic acid) and new commercial sanitizers, namely A (quaternary ammonium chloride), B (hydrogen peroxide, peracetic acid and peroctanoic acid), C (alkaline chloride foam), D (p-toluensulfonchloroamide, sodium salt) and E (ethoxylated nonylphenol and phosphoric acid), were determined. Phages were almost completely inactivated after eight months of storage at 25 °C, but viability was not affected at 4 °C, -20 °C or -80 °C. Both phages tolerated well HPH treatments. Phage iLp1308 showed higher thermal resistance than ф iLp84, but neither resisted 90 °C for 2 min. Best chemical inactivation was accomplished using peracetic acid or biocides A, C and E, whereas biocides B and D were completely ineffective. These results help to improve selection of chemical agents and physical treatments to effectively fight against phage infections in dairy plants.

  2. Biotransformation pathways of biocides and pharmaceuticals in freshwater crustaceans based on structure elucidation of metabolites using high resolution mass spectrometry.

    PubMed

    Jeon, Junho; Kurth, Denise; Hollender, Juliane

    2013-03-18

    So far, there is limited information on biotransformation mechanisms and products of polar contaminants in freshwater crustaceans. In the present study, metabolites of biocides and pharmaceuticals formed in Gammarus pulex and Daphnia magna were identified using liquid chromatography-high resolution mass spectrometry. Different confidence levels were assigned to the identification of metabolites without reference standards using a framework based on the background evidence used for structure elucidation. Twenty-five metabolites were tentatively identified for irgarol, terbutryn, tramadol, and venlafaxine in G. pulex (21 via oxidation and 4 via conjugation reactions) and 11 metabolites in D. magna (7 via oxidation and 4 via conjugation reactions), while no evidence of metabolites for clarithromycin and valsartan was found. Of the 360 metabolites predicted for the four parent compounds using pathway prediction systems and expert knowledge, 23 products were true positives, while 2 identified metabolites were unexpected products. Observed oxidative reactions included N- and O-demethylation, hydroxylation, and N-oxidation. Glutathione conjugation of selected biocides followed by subsequent reactions forming cysteine conjugates was described for the first time in freshwater invertebrates.

  3. Antifouling booster biocides in coastal waters of Panama: First appraisal in one of the busiest shipping zones.

    PubMed

    Batista-Andrade, Jahir Antonio; Caldas, Sergiane Souza; de Oliveira Arias, Jean Lucas; Castro, Italo Braga; Fillmann, Gilberto; Primel, Ednei Gilberto

    2016-11-15

    A baseline study for antifouling booster biocides in coastal waters of Panama is presented. Solid Phase Extraction (SPE) was used for extraction and Liquid Chromatography tandem Mass Spectrometry (LC-MS/MS) was applied for the quantification of irgarol 1051, diuron, (2-thiocyanomethylthio)benzothiazole (TCMTB), 4,5-dichloro-2-n-octyl-4-isothiazolin-3-one (DCOIT) and dichlofluanid. TCMTB, DCOIT and dichlofluanid were not detected in any seawater sample, while irgarol 1051 and diuron were found in four out of thirteen areas (<0.3 to 5.0ngL(-1) and <2.7 to 70ngL(-1), respectively). Although the hotspots were identified in areas influenced by marinas and in one of the ports, diuron and irgarol 1051 levels were all lower than the threshold levels set by the Environmental Quality Standard of United Kingdom. However, this is only a snapshot of the status of costal water contamination by antifouling booster biocides and a more comprehensive assessment is needed to assess risks associated to long term exposure.

  4. Radiologic Evaluation of Bone Loss at Implants with Biocide Coated Titanium Abutments: A Study in the Dog

    PubMed Central

    López-Píriz, Roberto; Solá-Linares, Eva; Granizo, Juan J.; Díaz-Güemes, Idohia; Enciso, Silvia; Bartolomé, José F.; Cabal, Belén; Esteban-Tejeda, Leticia; Torrecillas, Ramón; Moya, José S.

    2012-01-01

    The objective of the present study is to evaluate bone loss at implant abutments coated with a soda-lime glass containing silver nanoparticles subjected to experimental peri-implantitis. Five beagle dogs were used in the experiments, 3 implants were installed in each quadrant of the mandibles. Glass/n-Ag coted abutments were connected to implant platform. Cotton floss ligatures were placed in a submarginal position around the abutment necks and the animals were subject to a diet which allowed plaque accumulation, and after 15 weeks the dogs were sacrificed. Radiographs of all implant sites were obtained at the beginning and at the end of the experimentally induced peri-implantitis. The radiographic examination indicated that significant amounts of additional bone loss occurred in implants without biocide coating, considering both absolute and relative values of bone loss. Percentages of additional bone loss observed in implants dressed with a biocide coated abutment were about 3 times lower (p<0.006 distal aspect; and p<0.031 at mesial aspect) than the control ones. Within the limits of the present study it seems promising the use of soda-lime glass/nAg coatings on abutments to prevent peri-implant diseases. PMID:23285206

  5. Changes in the biocide susceptibility of Staphylococcus epidermidis and Escherichia coli cells associated with rapid attachment to plastic surfaces.

    PubMed

    Das, J R; Bhakoo, M; Jones, M V; Gilbert, P

    1998-05-01

    Differences in opacity between wells of a microtitre plate containing different volumes of inoculated growth medium reflected planktonic growth without any contribution from cells attached at the well surface. Simple algebra and a knowledge of the dependence of optical density upon sample path length (volume) for suspensions of differing cell density enables the generation of growth curves for attached populations (biofilms). In this manner, minimum inhibitory concentrations (MICs) were determined at various stages of growth (0-20 h), both for cells growing attached to the bases of the plate wells and, simultaneously, for cells growing in suspension above them. Biocides included cetrimide, polyhexamethylene biguanide, peracetic acid, phenoxyethanol and chloroxylenol. Results, expressed as planktonic:biofilm MIC ratios, showed susceptibility to change, not only as a function of attachment and biofilm formation, but also with respect to the nature of the chemical agent. In some instances, changes in susceptibility greater than twofold occurred immediately on attachment and could occur in the presence of biocide concentrations which exceeded the MIC.

  6. Characterizing the microbial colonization of a dolostone quarry: implications for stone biodeterioration and response to biocide treatments.

    PubMed

    Cámara, Beatriz; De los Ríos, Asuncion; Urizal, Marta; de Buergo, Mónica Alvarez; Varas, Maria Jose; Fort, Rafael; Ascaso, Carmen

    2011-08-01

    This study examines the microbial colonization of three fronts of an abandoned dolostone quarry (Redueña, Madrid, Spain) exposed to atmospheric conditions for different time periods since Roman times to the present. Through scanning electron microscopy in backscattered electron mode (SEM-BSE), endolithic colonization was predominantly detected in the most recently exposed front, while in the longer exposed quarry fronts, epilithic forms of growth were most often observed. These observations were confirmed by denaturing gradient gel electrophoresis (DGGE) analysis. Based on the distribution pattern of microbial colonization in the different quarry fronts, we then established a sequence of colonization events that took place over this long time frame. Bioalteration processes related to this sequential colonization were also identified. Characterizing these sequential processes can be useful for interpreting biodeterioration processes in historic dolostone monuments, especially those affecting constructions in the area of the Redueña stone quarry. In a second experimental stage, different biocide treatments were tested on this quarry rock to find the best way to avoid the microbial colonization effects identified. Through combined SEM-BSE/DGGE analysis, the efficacy of several biocides against the microorganisms inhabiting the dolostones was assessed after 4 and 16 months treatment. In general, all treatments were effective at reducing around 80% of the lichen cover, although effects on endolithic lithobiontic communities were dependent on how well the rock surface had been mechanically cleaned prior to treatment and gradually disappeared over time.

  7. 42. VIEW OF SYMONS 3 BY 6 FEET VIBRATING SCREEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    42. VIEW OF SYMONS 3 BY 6 FEET VIBRATING SCREEN FROM NORTHWEST. SCREEN IS BELOW AND FED BY DINGS MAGNETIC PULLEY - DRIVE GEAR VISIBLE. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  8. Quadruple screen test

    MedlinePlus

    Quad screen; Multiple marker screening; AFP plus; Triple screen test; AFP maternal; MSAFP; 4-marker screen; Down syndrome - quadruple; Trisomy 21 - quadruple; Turner syndrome - quadruple; Spina bifida - ...

  9. MRSA Screening

    MedlinePlus

    ... Tests Online. AACC is a not-for-profit organization and does not endorse non-AACC products and services. Advertising ... aureus Screening Related tests: Wound Culture All content on Lab Tests Online has been ...

  10. Hypertension screening

    NASA Technical Reports Server (NTRS)

    Foulke, J. M.

    1975-01-01

    An attempt was made to measure the response to an announcement of hypertension screening at the Goddard Space Center, to compare the results to those of previous statistics. Education and patient awareness of the problem were stressed.

  11. Developmental Screening

    MedlinePlus

    Learn More about Your Child’s Development: Developmental Monitoring and Screening Taking a first step, waving “bye-bye,” and pointing to something interesting are all developmental milestones, ...

  12. Get Screened

    MedlinePlus

    ... health. Depending on your age, sex, and medical history, you may need to be screened for things like: Certain types of cancer High blood pressure or high cholesterol Diabetes Osteoporosis (weak bones) ...

  13. Mixed hemi/ad-micelles coated magnetic nanoparticles for the entrapment of hemoglobin at the surface of a screen-printed carbon electrode and its direct electrochemistry and electrocatalysis.

    PubMed

    Amiri-Aref, Mohaddeseh; Raoof, Jahan Bakhsh; Kiekens, Filip; De Wael, Karolien

    2015-12-15

    An efficient procedure for the physical entrapment of proteins within a biocompatible matrix and their immobilization on electrode surfaces is of utmost importance in the fabrication of biosensors. In this work, the magnetic entrapment of hemoglobin (Hb) at the surface of a screen-printed carbon electrode (SPCE), through mixed hemi/ad-micelles (MHAM) array of positively charged surfactant supported iron oxide magnetic nanoparticles (Mag-NPs), is reported. The Hb/MHAM@Mag-NPs biocomposite is captured at SPCE by a super magnet (Hb/MHAM@Mag-NPs/SPCE). To gain insight in the configuration of the mixed hemi/ad-micelles of CTAB at Mag-NPs, zeta-potential measurements were performed. The entrapment of Hb at MHAM@Mag-NPs was confirmed by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Fourier transform infrared spectroscopy (FT-IR). Direct electron transfer of the Hb intercalated into the composite film showed a pair of well-defined quasi-reversible redox peak at formal potential of -0.255 V vs. Ag/AgCl corresponding to heme Fe(III)/Fe(II) redox couple. It shows that the MHAM@Mag-NPs composite could increase the adsorption ability for Hb, thus provides a facile direct electron transfer between the Hb and the substrate. The proposed biosensor showed excellent electrocatalytic activity to the H2O2 reduction in the wide concentration range from 5.0 to 300.0 µM obtained by amperometric measurement. The Michaelis-Menten constant (Km) value of Hb at the modified electrode is 55.4 µM, showing its high affinity. Magnetic entrapment offers a promising design for fast, convenient and effective immobilization of protein within a few minutes for determination of the target molecule in low sample volume at disposable cost-effective SPCE.

  14. [HCC screening].

    PubMed

    Albrecht, T

    2008-01-01

    Hepatocellular carcinoma (HCC) is one of the most frequently diagnosed tumour diseases throughout the world. In the vast majority of cases those affected are high-risk patients with chronic viral hepatitis and/or liver cirrhosis, which means there is a clearly identifiable target group for HCC screening. With resection, transplantation, and interventional procedures for local ablation, following early diagnosis curative treatment options are available with which 5-year survival rates of over 60% can be reached. Such early diagnosis is a reality only in a minority of patients, however, and in the majority of cases the disease is already in an advanced stage at diagnosis. One of the objects of HCC screening is diagnosis in an early stage when curative treatment is still possible. Precisely this is achieved by screening, so that the proportion of patients treated with curative intent is decisively higher. There is not yet any clear evidence as to whether this leads to a lowering of the mortality of HCC. As lower mortality is the decisive indicator of success for a screening programme the benefit of HCC screening has so far been neither documented nor refuted. Nonetheless, in large regions of the world it is the practice for high-risk patients to undergo HCC screening in the form of twice-yearly ultrasound examination and determination of AFP.

  15. Whole-brain black-blood imaging with magnetization-transfer prepared spin echo-like contrast: a novel sequence for contrast-enhanced brain metastasis screening at 3T.

    PubMed

    Yoneyama, Masami; Nakamura, Masanobu; Tabuchi, Takashi; Takemura, Atsushi; Obara, Makoto; Tatsuno, Satoshi; Sawano, Seishi

    2013-07-01

    In contrast-enhanced (CE) brain metastasis screening, coexistence of enhanced blood vessel suppression and higher tumor-to-parenchyma contrast may improve radiologists' performances in detecting brain metastases compared with conventional sequences. In this study, we propose a new scheme, allowing both suppression of blood signals and improvement of tumor-to-parenchyma contrast, using motion-sensitized driven equilibrium prepared 3D low-refocusing flip-angle turbo spin echo (TSE) ("magnetization transfer prepared spin echo"-like contrast volume examination: MATLVE) for brain metastasis screening at 3.0 T, and we compare MATLVE to conventional three-dimensional (3D)-gradient recalled echo (GRE) and 3D-TSE sequences. With the use of MATLVE, the signal intensity of CE blood decreased substantially. Furthermore, the contrast ratio of tumor-to-white matter was significantly higher than in either conventional 3D-GRE or 3D-TSE. MATLVE can be used for 3D volumetric post-CE black-blood imaging, and it may be effective in detecting small brain metastases by selectively enhancing tumor signals while suppressing blood signals.

  16. Principles and design of a novel magnetic force mechanical conditioning bioreactor for tissue engineering, stem cell conditioning, and dynamic in vitro screening.

    PubMed

    Dobson, Jon; Cartmell, Sarah H; Keramane, Ahmed; El Haj, Alicia J

    2006-09-01

    Mechanical conditioning of cells and tissue constructs in bioreactors is an important factor in determining the properties of tissue being produced. Mechanical conditioning within a bioreactor environment, however, has proven difficult. This paper presents the theoretical basis, design, and initial results of a mechanical conditioning system for cell and tissue culture which is based on biocompatible magnetic micro- and nanoparticles acting as a remote stress mechanism without invasion of the sterile bioreactor environment.

  17. Micropollutants in closed life-support systems: the case of triclosan, a biocide excreted via urine

    NASA Astrophysics Data System (ADS)

    Mastroleo, Felice; Pycke, Benny; Boon, Nico; de Wever, Heleen; Hendrickx, Larissa; Mastroleo, Felice; Wattiez, Ruddy; Mergeay, Max; Verstraete, Willy

    OBJECTIVES: The impact of triclosan on the growth and physiology of the bacterium Rhodospirillum rubrum was studied in the frame of the regenerative life-support system, Micro- Ecological Life Support System Alternative (MELiSSA). A wide range of compounds, such as steroid hormones, pharmaceuticals and personal care products, might enter the life support system via the excrements that are to be treated and recycled. Triclosan was chosen as the first compound to be tested because MELiSSA is a closed system, which is consequently particularly sensitive to compounds inhibiting the microbial metabolism. Because triclosan is increasingly used as an antimicrobial biocide in hygienic formulations (such as toothpaste, mouthwash, deodorants, etc.) and due to its chemical stability, it is considered an emerging pollutant in terrestrial ecosystems. METHODS: In a first phase, the triclosan concentration expected in the life-support system was estimated, the Minimal Inhibitory Concentration (MIC) was determined via plating, and the effect on growth kinetics was assessed by comparing growth parameters in the Gompertz model. In a second phase, the secondary effects of triclosan on cell physiology and gene expression were studied through flow-cytometry and microarray analyses, respectively. RESULTS: Based on the pharmacokinetic data from literature, the predicted concentration range is estimated to be 6-25µg/L triclosan in the Rhodospirillum rubrum compartment of the MELiSSA. The minimal inhibitory concentration of triclosan was determined to be 71 µg/L after 7 days of exposure on Sistrom medium. Upon exposure to 50-200µg/L triclosan, triclosan-resistant mutants of Rhodospirillum rubrum arose spontaneously at high frequency (3.1 ∗ 10 - 4). Analysis of the growth kinetics of the wild-type revealed that triclosan causes an important elongation of the lag-phase and a decrease in growth rate. At concentrations higher than 75mg/L(LD = 500mg/L), triclosan is bactericidal to wild

  18. Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics

    PubMed Central

    Curiao, Tânia; Marchi, Emmanuela; Viti, Carlo; Oggioni, Marco R.; Baquero, Fernando; Martinez, José Luis

    2015-01-01

    Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of the fabI gene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants of E. coli and K. pneumoniae were obtained after selection with biocides and/or antibiotics. E. coli TRIr mutants, including those with mutations in the fabI gene or in the expression of acrB, acrF, and marA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIr mutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIr mutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIr mutants had fitness costs, particularly marA-overexpressing (E. coli) or ramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIr mutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits. PMID

  19. Surface characterization of biocidal polyurethane modifiers having poly(3,3-substituted)oxetane soft blocks with alkylammonium side chains.

    PubMed

    Kurt, Pinar; Gamble, Lara J; Wynne, Kenneth J

    2008-06-03

    This paper focuses on surface characterization of P[ AB] copolyoxetane soft block polyurethanes having either fluorous (3FOx, -CH2OCH 2CF3) or PEG-like (ME2Ox, -CH2(OCH2CH2) 2OCH3), A side chains and alkylammonium, B side chains. Physical surface characterization data were analyzed in light of the previously observed order of antimicrobial effectiveness for a set of four surface modifiers. Ample physical evidence for surface concentration of fluorous 2 wt % P[ AB]-polyurethane modifiers was obtained from XPS, contact angles, ATR-IR spectroscopy, and TM-AFM. In TM-AFM phase imaging, the most effective biocidal surface modifier, 2 wt % HMDI-BD(30)/P[(3FOx)(C12)-0.89:0.11]-PU, showed a nanoscale phase-separated structure consisting of 200 nm domains with background features about 10 times smaller. Despite similar surface characterization data, the 2 wt % fluorous C6 analog ranked third in contact biocidal effectiveness. Physical evidence for surface concentration of 2 wt % P[(ME2Ox)(C12)-0.86:0.14]-PU was modest, considering that antimicrobial effectiveness was second only to 2 wt % HMDI-BD(30)/P[(3FOx)(C12)-0.89:0.11]-PU. In this set of surface modifiers, nanoscale morphology is largely driven by the fluorous component, whereas antimicrobial effectiveness is more strongly influenced by alkylammonium chain length. The effect of alkylammonium side chain length on surface concentration and antimicrobial behavior is more pronounced for ME2Ox polyurethanes compared to the 3FOx analogs.

  20. Triclosan and methyl-triclosan monitoring study in the northeast of Spain using a magnetic particle enzyme immunoassay and confirmatory analysis by gas chromatography mass spectrometry

    NASA Astrophysics Data System (ADS)

    Kantiani, Lina; Farré, Marinella; Asperger, Danijela; Rubio, Fernando; González, Susana; López de Alda, Maria J.; Petrović, Mira; Shelver, Weilin L.; Barceló, Damià

    2008-10-01

    SummaryFor the first time, the occurrence of triclosan and its metabolite methyl-triclosan was investigated in a typical Mediterranean area using a two-step methodology based on screening using a magnetic particle immunoassay (IA) and confirmatory analysis by solid phase extraction (SPE) followed by gas chromatography-mass spectrometry (GC-MS). In this study, 95 environmental samples were analyzed. A commercial immunoassay was assessed for use in the different types of water selected for this study. A large monitoring study was performed on the influent and the effluent of eight wastewater treatment plants (WWTPs), water samples from Ebro and Llobregat rivers, and drinking water. All wastewater samples tested in this study (influents and effluents) showed the presence of triclosan, with concentrations for raw influents being high (10 μg/L as average value). The percentages of triclosan removal for the WWTPs were evaluated (30-70%) along the different treatment processes showing that the best removal rates were obtained by the processes equipped with membrane bioreactors (MBRs). However, important concentrations of triclosan were detected even after treatment by MBRs. The presence of this biocide was confirmed in 50% of the river samples analyzed. Twenty two drinking water samples from the Barcelona city area were investigated, and in this case no triclosan was detected. Due to its properties and the widespread usage of triclosan, there is a need for monitoring and controlling the amounts present in wastewater effluents, river water, drinking water catchments areas, and drinking water. To this end, we present a feasible methodology using a magnetic particle-based immunoassay as a screening, followed by confirmatory analysis using solid phase extraction-gas chromatography-mass spectrometry (SPE-GC-MS).

  1. Hearing Screening

    ERIC Educational Resources Information Center

    Johnson-Curiskis, Nanette

    2012-01-01

    Hearing levels are threatened by modern life--headsets for music, rock concerts, traffic noises, etc. It is crucial we know our hearing levels so that we can draw attention to potential problems. This exercise requires that students receive a hearing screening for their benefit as well as for making the connection of hearing to listening.

  2. Wireless power transfer magnetic couplers

    DOEpatents

    Wu, Hunter; Gilchrist, Aaron; Sealy, Kylee

    2016-01-19

    A magnetic coupler is disclosed for wireless power transfer systems. A ferrimagnetic component is capable of guiding a magnetic field. A wire coil is wrapped around at least a portion of the ferrimagnetic component. A screen is capable of blocking leakage magnetic fields. The screen may be positioned to cover at least one side of the ferrimagnetic component and the coil. A distance across the screen may be at least six times an air gap distance between the ferrimagnetic component and a receiving magnetic coupler.

  3. Vision Screening

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Visi Screen OSS-C, marketed by Vision Research Corporation, incorporates image processing technology originally developed by Marshall Space Flight Center. Its advantage in eye screening is speed. Because it requires no response from a subject, it can be used to detect eye problems in very young children. An electronic flash from a 35 millimeter camera sends light into a child's eyes, which is reflected back to the camera lens. The photorefractor then analyzes the retinal reflexes generated and produces an image of the child's eyes, which enables a trained observer to identify any defects. The device is used by pediatricians, day care centers and civic organizations that concentrate on children with special needs.

  4. Transparent screens.

    PubMed

    Rosenthal, R J

    1988-01-01

    There is a kind of transitional phenomenon found among certain borderline patients which is quite distinct from Winnicott's transitional object. These are patients who are preoccupied with maintaining proper physical distance from their objects, in order to regulate anxieties about isolation on the one hand, and identity-annihilating closeness on the other. Since they believe the activity of looking to be intrusive and devouring, hence dangerous, transparent screens are interposed between self and other, and serve as protective barriers. These screens function intrapsychically as well, to split off or hide those aspects of the self felt to be unacceptable. The analyst may witness the failure of the screen in several ways: it may create too great a distance, isolating the individual and keeping him from life; it may become contaminated by projections and turn into a persecutor, or trap the individual, a state of intolerable claustrophobia; most dramatically, it may suddenly shatter. The latter is associated with psychosis and death, and its appearance may be a harbinger of suicide.

  5. Long-term changes in Prosobranchia (Gastropoda) abundances on the German North Sea coast: the role of the anti-fouling biocide tributyltin

    NASA Astrophysics Data System (ADS)

    Nehring, S.

    2000-05-01

    Tributyltin (TBT) has been used as a biocide in marine anti-fouling paints since the early 1970s. Due to its strong ecotoxicity and the relatively high levels in the water column as well as in port sediments on the German North Sea coast, it probably has negative ecological effects on organisms other than those targeted. An analysis of the long-term development of prosobranch stocks in the inner German Bight reveals a decrease in abundance of many species. For most species the decline cannot be attributed to TBT, but in four prosobranch species ( Buccinum undatum, Hydrobia ulvae, Littorina littorea and Nucella lapillus) significant ecological effects by TBT pollution are very probable. Although research for alternative non-TBT anti-fouling paints (e.g. biocide-free types on the basis of silicone) has been intensified, the potential threats to ecosystems and the ecotoxicological profiles of these alternatives have to be carefully evaluated.

  6. Effects of exposure to quaternary-ammonium-based biocides on antimicrobial susceptibility and tolerance to physical stresses in bacteria from organic foods.

    PubMed

    Gadea, Rebeca; Fernández Fuentes, Miguel Ángel; Pérez Pulido, Rubén; Gálvez, Antonio; Ortega, Elena

    2017-05-01

    In the present study, a collection of 76 biocide-sensitive bacterial strains isolated from organically produced food were adapted by repeated exposure to increasing concentrations of the quaternary ammonium compounds (QACs) benzalkonium chloride (BC) and hexadecylpyridinium chloride (HDP). The sensitivity of both wildtype strains and their corresponding QAC-adapted strains to other biocides and to antibiotics was studied. QAC tolerance increased in 88.2% of strains for BC and in 30.3% of strains for HDP, with increases in minimum inhibitory concentrations between 2 and over 100 fold. Adaptive resistance was stable after 20 subcultures in biocide-free medium for 7 and 5 of the BC- and HDP-adapted strains, respectively. Adaptation to BC and HDP also reduced the susceptibility to other biocides, mainly hexachlorophene (CF), didecyldimethylammonium bromide (AB), triclosan (TC) and chlorhexidine (CH). BC-adapted strains showed increased antibiotic resistance to ampicillin (AM) followed by sulfamethoxazol (SXT) and cefotaxime (CTX), and some showed increased sensitivity to ceftazidime (CAZ), CTX, AM and STX. Changes in antibiotic resistance in HDP-adapted strains were more heterogeneous and strain-dependent. Main efflux pump genes detected in QAC-adapted strains were acrB, sugE, norC, qacE and qacH, as well as antibiotic resistance genes aac(6_)-Ie-aph(2_)-Ia, aph(2_)-Ic, ant(4_)-Ia, lsa, mrsA/B, ereA, ermB and cat. Membrane anisotropy experiments revealed that QAC adaptation induced an increase in membrane rigidity in the case of BC, while response to HDP was more heterogeneous and strain-dependent. Growth capacity was significantly higher in some QAC-adapted strains and strain-dependent changes in heat tolerance were also detected in QAC-adapted strains. Gastric acid or bile resistances do not seem to be influenced by QAC adaptation.

  7. Exposure of Escherichia coli ATCC 12806 to sublethal concentrations of food-grade biocides influences its ability to form biofilm, resistance to antimicrobials, and ultrastructure.

    PubMed

    Capita, Rosa; Riesco-Peláez, Félix; Alonso-Hernando, Alicia; Alonso-Calleja, Carlos

    2014-02-01

    Escherichia coli ATCC 12806 was exposed to increasing subinhibitory concentrations of three biocides widely used in food industry facilities: trisodium phosphate (TSP), sodium nitrite (SNI), and sodium hypochlorite (SHY). The cultures exhibited an acquired tolerance to biocides (especially to SNI and SHY) after exposure to such compounds. E. coli produced biofilms (as observed by confocal laser scanning microscopy) on polystyrene microtiter plates. Previous adaptation to SNI or SHY enhanced the formation of biofilms (with an increase in biovolume and surface coverage) both in the absence and in the presence (MIC/2) of such compounds. TSP reduced the ability of E. coli to produce biofilms. The concentration of suspended cells in the culture broth in contact with the polystyrene surfaces did not influence the biofilm structure. The increase in cell surface hydrophobicity (assessed by a test of microbial adhesion to solvents) after contact with SNI or SHY appeared to be associated with a strong capacity to form biofilms. Cultures exposed to biocides displayed a stable reduced susceptibility to a range of antibiotics (mainly aminoglycosides, cephalosporins, and quinolones) compared with cultures that were not exposed. SNI caused the greatest increase in resistances (14 antibiotics [48.3% of the total tested]) compared with TSP (1 antibiotic [3.4%]) and SHY (3 antibiotics [10.3%]). Adaptation to SHY involved changes in cell morphology (as observed by scanning electron microscopy) and ultrastructure (as observed by transmission electron microscopy) which allowed this bacterium to persist in the presence of severe SHY challenges. The findings of the present study suggest that the use of biocides at subinhibitory concentrations could represent a public health risk.

  8. Combined effects of NaCl, NaOH, and biocides (monolaurin or lauric acid) on inactivation of Listeria monocytogenes and Pseudomonas spp.

    PubMed

    Vasseur, C; Rigaud, N; Hébraud, M; Labadie, J

    2001-09-01

    This study highlighted combinations of chemical stresses that could decrease or eliminate Listeria monocytogenes and Pseudomonas spp. surviving in food processing plants. Strains of L. monocytogenes, Pseudomonas fragi, and Pseudomonas fluorescens isolated from processing environments (meat and milk) were grown at 20 degrees C up to the early stationary phase. The strains were then subjected to 30 min of physicochemical treatments. These treatments included individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (fatty acids) challenges. Survival of the strains was studied after individual or combined acid (acetic acid), alkaline (NaOH), osmotic (NaCl), and biocides (monolaurin, lauric acid) challenges. Individual pH shocks had lower efficiencies than those used in combinations with other parameters. The treatment pH 5.4 followed by pH 10.5 had a low efficiency against L. monocytogenes. The opposite combination, pH 10.5 followed by pH 5.4, led to a 3-log reduction of the L. monocytogenes population. Pseudomonas spp. strains were much more sensitive than L. monocytogenes, and population reductions of 5 and 8 log (total destruction), respectively, were observed after the same treatments. As for L. monocytogenes, the combination pH 10.5 followed by pH 5.4 is more deleterious than the opposite. Whatever the bacterial species, the most efficient treatments were combinations of alkaline, osmotic, and biocide shocks. For instance, the combination pH 10.5 and 10% NaCl plus biocides showed reductions of 5 to 8 log for both bacteria. The origins of the observed lethal effects are discussed.

  9. Breast cancer screening

    MedlinePlus

    Mammogram - breast cancer screening; Breast exam - breast cancer screening; MRI - breast cancer screening ... performed to screen women to detect early breast cancer when it is more likely to be cured. ...

  10. D-amino acids for the enhancement of a binary biocide cocktail consisting of THPS and EDDS against an SRB biofilm.

    PubMed

    Xu, D; Wen, J; Fu, W; Gu, T; Raad, I

    2012-04-01

    Biofilms of sulfate reducing bacteria (SRB) are often responsible for Microbiologically Influenced Corrosion (MIC) that is a major problem in the oil and gas industry as well as water utilities and other industries. This work was inspired by recent reports that some D: -amino acids may be useful in the control of microbial biofilms. A D: -amino acid mixture with equimolar D: -tyrosine, D: -methionine, D: -tryptophan and D: -leucine was tested in this work for their enhancement of a biocide cocktail containing tetrakis (hydroxymethyl) phosphonium sulfate (THPS) and ethylenediamine-N,N'-disuccinic acid (EDDS). Desulfovibrio vulgaris (ATCC 7757) was cultured in ATCC 1249 medium. Its biofilm was grown on C1018 carbon steel coupons. Experimental results indicated that the triple biocide cocktail consisting of 30 ppm THPS, 500 ppm EDDS and 6.6 ppm D: -amino acid mixture (with equimolar D: -tyrosine, D: -methionine, D: -tryptophan and D: -leucine) was far more effective than THPS and EDDS alone and their binary combination. The triple biocide cocktail effectively prevented SRB biofilm establishment and removed the established SRB biofilm. The D: -amino acid mixture alone did not show significant effects in the two tasks even at 660 ppm.

  11. Structure, tribocorrosion and biocide characterization of Ca, P and I containing TiO2 coatings developed by plasma electrolytic oxidation

    NASA Astrophysics Data System (ADS)

    de Viteri, V. Sáenz; Bayón, R.; Igartua, A.; Barandika, G.; Moreno, J. Esteban; Peremarch, C. Pérez-Jorge; Pérez, M. Martínez

    2016-03-01

    In hip joint implants, in particular in the stems, wear-corrosion effects can accelerate the degradation of the biomaterial. The lack of osseointegration and the risk of contracting implant-associated infections may be other reasons for a premature failure of the implant. In this work, TiO2 coatings have been developed by means of plasma electrolytic oxidation (PEO) technique in order to achieve wear-resistant hard coatings with osseointegration ability and biocide characteristics. During the PEO process, elements that favor cell growth, like Ca and P, were introduced into the coating. With the purpose of providing the coating with antibacterial properties iodine was added like biocide agent. The microstructure and chemical composition of the developed coatings were analyzed in order to see if the surface of the films was suitable for the cell attachment. The effect of wear-corrosion synergy was studied by means of tribocorrosion tests. Finally, the biocide capacity of iodine against Staphylococcus aureus and Staphylococcus epidermidis was analyzed through bacterial adhesion tests. High wear and corrosion resistance was shown in one of the developed coatings. The achieved surface microstructures seem to be appropriate to improve the osseointegration with proper pore size and porosity index. The antibacterial capacity of iodine was confirmed for S. epidermidis.

  12. Singular field response and singular screening of vacancies in antiferromagnets.

    PubMed

    Wollny, Alexander; Andrade, Eric C; Vojta, Matthias

    2012-10-26

    For isolated vacancies in ordered local-moment antiferromagnets we show that the magnetic-field linear-response limit is generically singular: The magnetic moment associated with a vacancy in zero field is different from that in a finite field h in the limit h→0(+). The origin is a universal and singular screening cloud, which moreover leads to perfect screening as h→0(+) for magnets which display spin-flop bulk states in the weak-field limit.

  13. Flexible magnetic planning boards are easily transported

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Easily transportable preprinted magnetic planning boards are made by coating thin sheet steel with clear plastic. Flexible magnetic boards used with paper charts are constructed from close mesh steel screen.

  14. Polymorphic variation in susceptibility and metabolism of triclosan-resistant mutants of Escherichia coli and Klebsiella pneumoniae clinical strains obtained after exposure to biocides and antibiotics.

    PubMed

    Curiao, Tânia; Marchi, Emmanuela; Viti, Carlo; Oggioni, Marco R; Baquero, Fernando; Martinez, José Luis; Coque, Teresa M

    2015-01-01

    Exposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selected Escherichia coli and Klebsiella pneumoniae mutants. E. coli and K. pneumoniae mutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of the fabI gene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRI(r)) and triclosan-hypersusceptible (TRI(hs)) mutants of E. coli and K. pneumoniae were obtained after selection with biocides and/or antibiotics. E. coli TRI(r) mutants, including those with mutations in the fabI gene or in the expression of acrB, acrF, and marA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRI(r) mutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRI(r) mutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRI(r) mutants had fitness costs, particularly marA-overexpressing (E. coli) or ramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRI(r) mutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive

  15. Influence of temperature on the degradation of isothiazolone biocides in aqueous media and in a metalworking fluid concentrate

    SciTech Connect

    Barman, B.N.

    1994-05-01

    The degradation of the active component of two isothiazolone biocides has been monitored at 24{degrees}, 40{degrees}, and 60{degrees} by reversed-phase liquid chromatography. The first-order rate constants are measured, and temperature-dependent kinetic data are used to show that the rate of degradation is doubled if the temperature is increased by 5{degrees}C and 6{degrees}C in aqueous media by pH 8.5 and 9.6, respectively. At pH 5.5, the active component is found to be stable at 24{degrees} and 40{degrees}C, and its depletion at60{degrees}C is about 10 percent over a period of three and one-half months. An estimated half-life of the active component in a metalworking fluid concentrate is six months at 24{degrees}C. However, at both 40{degrees} and 60{degrees}C, its degradation appears to be a two-step process. Initially, the concentration remains invariant or decreases slowly. This is followed by a rapid, first-order kinetic process. The overall times required for 50 percent loss of the active component are 12.2 and 1.6 days at 40{degrees} and 60{degrees}C, respectively.

  16. Effects of antifouling booster biocide Irgarol 1051 on the structure of free living nematodes: a laboratory experiment.

    PubMed

    Hannachi, Amel; Elarbaoui, Soumaya; Khazri, Abdelhafidh; D'Agostino, Fabio; Sellami, Badreddine; Beyrem, Hamouda; Gambi, Cristina; Danovaro, Roberto; Mahmoudi, Ezzeddine

    2016-07-13

    A mesocosm experiment was conducted to evaluate the effects of Irgarol on nematode diversity, composition and trophic structure. Sediment samples were experimentally contaminated using four increasing Irgarol concentrations [I1 (11.5 ng g(-1)), I2 (35 ng g(-1)), I3 (105 ng g(-1)) and I4 (315 ng g(-1))] and compared to non-contaminated sediments (controls). Nematode diversity as the number of nematodes species (S) and species richness (d) was significantly lower in all Irgarol treatments than in the controls while the evenness (J') increased significantly in I4 treated mesocosms. The nematode species composition significantly changed following Irgarol concentrations. Paracomesoma dubiun and Terschellingia longicaudata appeared as "tolerant" species to the highest Irgarol concentration. Additionally, Chromadorina germanica and Microlaimus cyatholaimoides appeared as "opportunistic" species. In contrast, Daptonema normandicum seemed to be a "sensitive" species to Irgarol contamination. Irgarol modified also the nematode trophic structure where the relative abundance of deposit feeders decreased significantly in all the treatments compared to control mesocosms and optional predators decreased only in treated mesocosms with I3. Epigrowth feeders increased significantly in treated mesocosms with I3 and I4 and the microvores increased with I1 and decreased with I4. The relative abundance of ciliate consumers appeared unaffected by the presence of Irgarol contamination. Our results open new perspectives on the potential impact of antifouling booster biocide Irgarol 1051 on nematode biodiversity and functional diversity as trophic structures.

  17. Analysis of isothiazolinone biocides in paper for food packaging by ultra-high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Lin, Q-B; Wang, T-J; Song, H; Li, B

    2010-12-01

    A novel and simple method to detect isothiazolinone-type biocides (2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BIT) and 2-octyl-3-isothiazolinone (OIT)) in paper used for food packaging by ultrasonic extraction coupled with UPLC-MS/MS was developed. Parameters affecting process efficiency such as extraction solvents, UPLC mobile phase, gradient elution procedure and MS/MS conditions were studied to optimise the operating conditions. Using the optimised gradient elution procedure, the retention time was less than 6 min. The limits of detection (LODs) were found to be between 0.001 and 0.010 mg kg⁻¹, which was validated using actual concentrations. After diluting the standard solution with a blank matrix, the linear calibration curve ranges were 0.002-1.000 mg kg⁻¹ for BIT and OIT, 0.005-1.000 mg kg⁻¹ for MI, and 0.020-1.000 mg kg⁻¹ for CMI, with correlation coefficients higher than 0.9985 (n = 6). A good level of precision with a mean recovery greater than 81.3% and a relative standard deviation (RSD) less than 6.2% were also obtained. A methodology has been proposed for the analysis of isothiazolinones in paper.

  18. Environmental risks associated with booster biocides leaching from spent anti-fouling paint particles in coastal environments.

    PubMed

    Hasan, Chowdhury K; Turner, Andrew; Readman, James; Frickers, Trish

    2014-12-01

    Boat maintenance facilities in coastal areas contribute a significant amount of antifouling paint particles (APP) to coastal environments. Very few studies have concentrated on the leaching of booster biocides embedded in old paint particles. Therefore, this study attempted to assess the leaching of Dichlofluanid and Irgarol 1051 from APP collected from Mayflower Marina in southwest England. They were analyzed by GC-MS. A leaching experiment revealed that a considerable amount of Dichlofluanid (ca. 24 μg/L) leached from 0.4 g/L of APP after the first hour, followed by a marked decline in the amount measured in the water over time, almost degrading after 24 h in seawater, affording less of an environmental threat to non-target organisms. Conversely, Irgarol 1051 appeared to be persistent and continuously leached from the 0.4 g/L of APP even after 10 days, yielding a concentration of 0.61 μg/L in seawater, potentially posing a significant threat to the aquatic environment through leaching from APP.

  19. Co-Selection of Resistance to Antibiotics, Biocides and Heavy Metals, and Its Relevance to Foodborne Pathogens

    PubMed Central

    Wales, Andrew D.; Davies, Robert H.

    2015-01-01

    Concerns have been raised in recent years regarding co-selection for antibiotic resistance among bacteria exposed to biocides used as disinfectants, antiseptics and preservatives, and to heavy metals (particularly copper and zinc) used as growth promoters and therapeutic agents for some livestock species. There is indeed experimental and observational evidence that exposure to these non-antibiotic antimicrobial agents can induce or select for bacterial adaptations that result in decreased susceptibility to one or more antibiotics. This may occur via cellular mechanisms that are protective across multiple classes of antimicrobial agents or by selection of genetic determinants for resistance to non-antibiotic agents that are linked to genes for antibiotic resistance. There may also be relevant effects of these antimicrobial agents on bacterial community structure and via non-specific mechanisms such as mobilization of genetic elements or mutagenesis. Notably, some co-selective adaptations have adverse effects on fitness in the absence of a continued selective pressure. The present review examines the evidence for the significance of these phenomena, particularly in respect of bacterial zoonotic agents that commonly occur in livestock and that may be transmitted, directly or via the food chain, to human populations. PMID:27025641

  20. Debye screening

    NASA Astrophysics Data System (ADS)

    Brydges, David C.; Federbush, Paul

    1980-10-01

    The existence and exponential clustering of correlation functions for a classical coulomb system at low density or high temperature are proven using methods from constructive quantum field theory, the sine gordon transformation and the Glimm, Jaffe, Spencer expansion about mean field theory. This is a vindication of a belief of long standing among physicists, known as Debye screening. That is, because of special properties of the coulomb potential, the configurations of significant probability are those in which the long range parts of r -1 are mostly cancelled, leaving an effective exponentially decaying potential acting between charge clouds. This paper generalizes a previous paper of one of the authors in which these results were obtained for a special lattice system. The present treatment covers the continuous mechanics situation, with essentially arbitrary short range forces and charge species. Charge symmetry is not assumed.

  1. Breast cancer screening controversies: who, when, why, and how?

    PubMed

    Chetlen, Alison; Mack, Julie; Chan, Tiffany

    2016-01-01

    Mammographic screening is effective in reducing mortality from breast cancer. The issue is not whether mammography is effective, but whether the false positive rate and false negative rates can be reduced. This review will discuss controversies including the reduction in breast cancer mortality, overdiagnosis, the ideal screening candidate, and the optimal imaging modality for breast cancer screening. The article will compare and contrast screening mammography, tomosynthesis, whole-breast screening ultrasound, magnetic resonance imaging, and molecular breast imaging. Though supplemental imaging modalities are being utilized to improve breast cancer diagnosis, mammography still remains the gold standard for breast cancer screening.

  2. Antioxidant and biocidal activities of Carum nigrum (seed) essential oil, oleoresin, and their selected components.

    PubMed

    Singh, Gurdip; Marimuthu, Palanisamy; de Heluani, Carola S; Catalan, Cesar A N

    2006-01-11

    In the present study, chemical constituents of the essential oil and oleoresin of the seed from Carum nigrum obtained by hydrodistillation and Soxhlet extraction using acetone, respectively, have been studied by GC and GC-MS techniques. The major component was dillapiole (29.9%) followed by germacrene B (21.4%), beta-caryophyllene (7.8%), beta-selinene (7.1%), and nothoapiole (5.8%) along with many other components in minor amounts. Seventeen components were identified in the oleoresin (Table 2) with dillapiole as a major component (30.7%). It also contains thymol (19.1%), nothoapiole (15.2.3%), and gamma-elemene (8.0%). The antioxidant activity of both the essential oil and oleoresin was evaluated in mustard oil by monitoring peroxide, thiobarbituric acid, and total carbonyl and p-anisidine values of the oil substrate. The results showed that both the essential oil and oleoresin were able to reduce the oxidation rate of the mustard oil in the accelerated condition at 60 degrees C in comparison with synthetic antioxidants such as butylated hydroxyanisole and butylated hydroxytoluene at 0.02%. In addition, individual antioxidant assays such as linoleic acid assay, DPPH scavenging activity, reducing power, hydroxyl radical scavenging, and chelating effects have been used. The C. nigrum seed essential oil exhibited complete inhibition against Bacillus cereus and Pseudomonas aeruginosa at 2000 and 3000 ppm, respectively, by agar well diffusion method. Antifungal activity was determined against a panel of foodborne fungi such as Aspergillus niger, Penicillium purpurogenum, Penicillium madriti, Acrophialophora fusispora, Penicillium viridicatum, and Aspergillus flavus. The fruit essential oil showed 100% mycelial zone inhibition against P. purpurogenum and A. fusispora at 3000 ppm in the poison food method. Hence, both oil and oleoresin could be used as an additive in food and pharmaceutical preparations after screening.

  3. Unimpeded permeation of water through biocidal graphene oxide sheets anchored on to 3D porous polyolefinic membranes

    NASA Astrophysics Data System (ADS)

    Mural, Prasanna Kumar S.; Jain, Shubham; Kumar, Sachin; Madras, Giridhar; Bose, Suryasarathi

    2016-04-01

    3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and hot-pressed samples revealed a clear picture as to how the morphology develops and coarsens over a function of time during post-processing operations like compression molding. The coarsening of PE/PEO blends was traced using X-ray micro-computed tomography and scanning electron microscopy (SEM) of annealed blends at different times. It is now understood from X-ray micro-computed tomography that by the addition of a compatibilizer (here lightly maleated PE), a stable morphology can be visualized in 3D. In order to anchor biocidal graphene oxide sheets onto these 3D porous membranes, the PE membranes were chemically modified with acid/ethylene diamine treatment to anchor the GO sheets which were further confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and surface Raman mapping. The transport properties through the membrane clearly reveal unimpeded permeation of water which suggests that anchoring GO on to the membranes does not clog the pores. Antibacterial studies through the direct contact of bacteria with GO anchored PE membranes resulted in 99% of bacterial inactivation. The possible bacterial inactivation through physical disruption of the bacterial cell wall and/or reactive oxygen species (ROS) is discussed herein. Thus this study opens new avenues in designing polyolefin based antibacterial 3D porous membranes for water purification.3D porous membranes were developed by etching one of the phases (here PEO, polyethylene oxide) from melt-mixed PE/PEO binary blends. Herein, we have systematically discussed the development of these membranes using X-ray micro-computed tomography. The 3D tomograms of the extruded strands and

  4. Determination of biocides in different environmental matrices by use of ultra-high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Chen, Zhi-Feng; Ying, Guang-Guo; Lai, Hua-Jie; Chen, Feng; Su, Hao-Chang; Liu, You-Sheng; Peng, Fu-Qiang; Zhao, Jian-Liang

    2012-12-01

    A sensitive and robust method using solid-phase extraction and ultrasonic extraction for preconcentration followed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) has been developed for determination of 19 biocides: eight azole fungicides (climbazole, clotrimazole, ketoconazole, miconazole, fluconazole, itraconazole, thiabendazole, and carbendazim), two insect repellents (N,N-diethyl-3-methylbenzamide (DEET), and icaridin (also known as picaridin)), three isothiazolinone antifouling agents (1,2-benzisothiazolinone (BIT), 2-n-octyl-4-isothiazolinone (OIT), and 4,5-dichloro-2-n-octyl-isothiazolinone (DCOIT)), four paraben preservatives (methylparaben, ethylparaben, propylparaben, and butylparaben), and two disinfectants (triclosan and triclocarban) in surface water, wastewater, sediment, sludge, and soil. Recovery of the target compounds from surface water, influent, effluent, sediment, sludge, and soil was mostly in the range 70-120%, with corresponding method quantification limits ranging from 0.01 to 0.31 ng L(-1), 0.07 to 7.48 ng L(-1), 0.01 to 3.90 ng L(-1), 0.01 to 0.45 ng g(-1), 0.01 to 6.37 ng g(-1), and 0.01 to 0.73 ng g(-1), respectively. Carbendazim, climbazole, clotrimazole, methylparaben, miconazole, triclocarban, and triclosan were detected at low ng L(-1) (or ng g(-1)) levels in surface water, sediment, and sludge-amended soil. Fifteen target compounds were found in influent samples, at concentrations ranging between 0.4 (thiabendazole) and 372 ng L(-1) (methylparaben). Fifteen target compounds were found in effluent samples, at concentrations ranging between 0.4 (thiabendazole) and 114 ng L(-1) (carbendazim). Ten target compounds were found in dewatered sludge samples, at concentrations ranging between 1.1 (DEET) and 887 ng g(-1) (triclocarban).

  5. Biodegradation of a Biocide (Cu-N-Cyclohexyldiazenium Dioxide) Component of a Wood Preservative by a Defined Soil Bacterial Community▿

    PubMed Central

    Jakobs-Schönwandt, Désirée; Mathies, Helena; Abraham, Wolf-Rainer; Pritzkow, Wolfgang; Stephan, Ina; Noll, Matthias

    2010-01-01

    The wood protection industry has refined their products from chrome-, copper-, and arsenate-based wood preservatives toward solely copper-based preservatives in combination with organic biocides. One of these is Cu-HDO, containing the chelation product of copper and N-cyclohexyldiazenium dioxide (HDO). In this study, the fate of isotope-labeled (13C) and nonlabeled (12C) Cu-HDO incorporated in wood sawdust mixed with soil was investigated. HDO concentration was monitored by high-pressure liquid chromatography. The total carbon and the δ13C content of respired CO2, as well as of the soil-wood-sawdust mixture, were determined with an elemental analyzer-isotopic ratio mass spectrometer. The concentration of HDO decreased significantly after 105 days of incubation, and after 24 days the 13CO2 concentration respired from soil increased steadily to a maximum after 64 days of incubation. Phospholipid fatty acid-stable isotope probing (PFA-SIP) analysis revealed that the dominant PFAs C19:0d8,9, C18:0, C18:1ω7, C18:2ω6,9, C17:1d7,8, C16:0, and C16:1ω7 were highly enriched in their δ13C content. Moreover, RNA-SIP identified members of the phylum Acidobacteria and the genera Phenylobacterium and Comamonas that were assimilating carbon from HDO exclusively. Cu-HDO as part of a wood preservative effectively decreased fungal wood decay and overall microbial respiration from soil. In turn, a defined bacterial community was stimulated that was able to metabolize HDO completely. PMID:20952650

  6. Biodegradation of a biocide (Cu-N-cyclohexyldiazenium dioxide) component of a wood preservative by a defined soil bacterial community.

    PubMed

    Jakobs-Schönwandt, Désirée; Mathies, Helena; Abraham, Wolf-Rainer; Pritzkow, Wolfgang; Stephan, Ina; Noll, Matthias

    2010-12-01

    The wood protection industry has refined their products from chrome-, copper-, and arsenate-based wood preservatives toward solely copper-based preservatives in combination with organic biocides. One of these is Cu-HDO, containing the chelation product of copper and N-cyclohexyldiazenium dioxide (HDO). In this study, the fate of isotope-labeled ((13)C) and nonlabeled ((12)C) Cu-HDO incorporated in wood sawdust mixed with soil was investigated. HDO concentration was monitored by high-pressure liquid chromatography. The total carbon and the δ(13)C content of respired CO(2), as well as of the soil-wood-sawdust mixture, were determined with an elemental analyzer-isotopic ratio mass spectrometer. The concentration of HDO decreased significantly after 105 days of incubation, and after 24 days the (13)CO(2) concentration respired from soil increased steadily to a maximum after 64 days of incubation. Phospholipid fatty acid-stable isotope probing (PFA-SIP) analysis revealed that the dominant PFAs C(19:0)d8,9, C(18:0), C(18:1)ω7, C(18:2)ω6,9, C(17:1)d7,8, C(16:0), and C(16:1)ω7 were highly enriched in their δ(13)C content. Moreover, RNA-SIP identified members of the phylum Acidobacteria and the genera Phenylobacterium and Comamonas that were assimilating carbon from HDO exclusively. Cu-HDO as part of a wood preservative effectively decreased fungal wood decay and overall microbial respiration from soil. In turn, a defined bacterial community was stimulated that was able to metabolize HDO completely.

  7. A Novel Strategy for Control of Microbial Biofilms through Generation of Biocide at the Biofilm-Surface Interface

    PubMed Central

    Wood, P.; Jones, M.; Bhakoo, M.; Gilbert, P.

    1996-01-01

    Biofilms of a mucoid clinical isolate of Pseudomonas aeruginosa (24 h; ca. 10(sup6) CFU/cm(sup2)) were established by immersion of polymer discs in nutrient broth cultures at 37(deg)C. Biofilms exposed for 30 min to various concentrations (0 to 3 mg/ml) of hydrogen peroxide or potassium monopersulfate were rinsed and shaken vigorously in sterile saline to detach loosely associated cells, and the residual viable attached population was quantified by a blot succession method on agar plates. Incorporation of copper and cobalt phthalocyanine catalysts within the polymers significantly enhanced the activity of these oxidizing biocides towards biofilm bacteria by several orders of magnitude. Biofilms established on the control discs resisted treatment with concentrations of either agent of up to 3 mg/ml. Enhancement through incorporation of a catalyst was such that concentrations of potassium monopersulfate of as low as 20 (mu)g/ml gave no recoverable survivors either on the discs or within the washings. Catalysts such as these will promote the formation of active oxygen species from a number of oxidizing agents such as peroxides and persulfates, and it is thought that generation of these at the surface-biofilm interface concentrates the antimicrobial effect to the interfacial cells and generates a diffusion pump which further provides active species to the biofilm matrix. The survivors of low-concentration treatments with these agents were more readily removed from the catalyst-containing discs than from the control discs. This indicated advantages gained in hygienic cleansing of such modified surfaces. PMID:16535366

  8. Combined biocidal action of silver nanoparticles and ions against Chlorococcales (Scenedesmus quadricauda, Chlorella vulgaris) and filamentous algae (Klebsormidium sp.).

    PubMed

    Zouzelka, Radek; Cihakova, Pavlina; Rihova Ambrozova, Jana; Rathousky, Jiri

    2016-05-01

    Despite the extensive research, the mechanism of the antimicrobial and biocidal performance of silver nanoparticles has not been unequivocally elucidated yet. Our study was aimed at the investigation of the ability of silver nanoparticles to suppress the growth of three types of algae colonizing the wetted surfaces or submerged objects and the mechanism of their action. Silver nanoparticles exhibited a substantial toxicity towards Chlorococcales Scenedesmus quadricauda, Chlorella vulgaris, and filamentous algae Klebsormidium sp., which correlated with their particle size. The particles had very good stability against agglomeration even in the presence of multivalent cations. The concentration of silver ions in equilibrium with nanoparticles markedly depended on the particle size, achieving about 6 % and as low as about 0.1 % or even less for the particles 5 nm in size and for larger ones (40-70 nm), respectively. Even very limited proportion of small particles together with larger ones could substantially increase concentration of Ag ions in solution. The highest toxicity was found for the 5-nm-sized particles, being the smallest ones in this study. Their toxicity was even higher than that of silver ions at the same silver concentration. When compared as a function of the Ag(+) concentration in equilibrium with 5-nm particles, the toxicity of ions was at least 17 times higher than that obtained by dissolving silver nitrite (if not taking into account the effect of nanoparticles themselves). The mechanism of the toxicity of silver nanoparticles was found complex with an important role played by the adsorption of silver nanoparticles and the ions released from the particles on the cell surface. This mechanism could be described as some sort of synergy between nanoparticles and ions. While our study clearly showed the presence of this synergy, its detailed explanation is experimentally highly demanding, requiring a close cooperation between materials scientists

  9. Prostate cancer screening

    MedlinePlus

    Prostate cancer screening - PSA; Prostate cancer screening - digital rectal exam; Prostate cancer screening - DRE ... level of PSA could mean you have prostate cancer. But other conditions can also cause a high ...

  10. Mental Health Screening Center

    MedlinePlus

    ... confidential online depression screening Anxiety The Hamilton Anxiety Scale was authored by Max Hamilton. It is in ... mania screening Childhood Mania The Child Mania Rating Scale (CMRS) is a parent screening instrument for mania ...

  11. Health Screenings and Immunizations

    MedlinePlus

    ... your primary doctor. Blood Tests – A Common Screening Method (Source: National Heart, Lung, and Blood Institute) Click ... tests, see What Are Blood Tests? Other Screening Methods Doctors can't screen for all diseases and ...

  12. Screening for Prostate Cancer

    MedlinePlus

    ... for prostate cancer. It concluded that the expected harms of PSA screening are greater than the potential ... exam or other screening tests. Potential Benefits and Harms The main goal of a cancer screening test ...

  13. Alcohol Use Screening

    MedlinePlus

    ... Centers Mental Health Medical Library Alcohol Use Screening (AUDIT-C) - Instructions The following questions are a screening ... is also text-only version . Alcohol Use Screening (AUDIT-C) - Manual Instructions The following questions are a ...

  14. Prenatal Genetic Screening Tests

    MedlinePlus

    ... Education & Events Advocacy For Patients About ACOG Prenatal Genetic Screening Tests Home For Patients Search FAQs Prenatal ... Screening Tests FAQ165, September 2016 PDF Format Prenatal Genetic Screening Tests Pregnancy What is prenatal genetic testing? ...

  15. Screening for Specific Phobias

    MedlinePlus

    ... Anxiety FAQs Screen Yourself ADAA Online Support Group Personal Stories of Triumph "Triumph" E-News Webinars Blog ... Screening for Posttraumatic Stress Disorder (PTSD) Screening for Social Anxiety ... to fulfill responsibilities with work, school, or family? Yes No placed ...

  16. Analysis of the proposed EU regulation concerning biocide products and its opportunities for alternative approaches and a toxicology for the 21st century (t4 report).

    PubMed

    Ferrario, Daniele; Rabbit, Richard R

    2012-01-01

    On June 12, 2009, the European Commission adopted a proposal for a Regulation concerning the placement on the market and use of biocidal products, which, when it enters into force on January 1, 2013, will repeal and replace Directive 98/8/EC. The main reason for the revision of the current Directive was to promote best practices for environmental and human health protection, along with implementation of current developments in safety testing in order to create safer biocides. Moreover, the proposed Regulation aims to take into consideration the newest legislation on chemicals. This article evaluates the proposed Regulation in comparison to Directive 98/8/EC. Although the new proposal requires the sharing of vertebrate animal test data, both for product authorization and for newly developed active substances, it misses - in contrast to REACH - the opportunity to recognize the accelerating development of alternative approaches to animal testing, most recently with new momentum provided by "Toxicity Testing for the 21st Century", and to support the evolution of toxicology towards a new approach to testing. The new methods promise not only to decrease animal pain and suffering, but also to provide faster results and better prediction for human risk assessment compared to traditional methods. Unfortunately, methods mandated for human risk assessment in the proposal are still mainly based on traditional animal study extrapolation. We put forward and discuss possible alternative strategies, such as in vitro testing, integrated testing strategies, toxicokinetics, "omics", systems biology, bioinformatics, and computational modeling, all of which could be more encouraged by the proposal. Current opportunities to improve our tools for biocide risk assessment are discussed, delineating advantages, limitations, and development needs. It is suggested to open the proposed Regulation to alternative approaches that are based on human biology more than on extrapolation from animals

  17. What Is Carrier Screening?

    MedlinePlus

    ... Primary care providers Specialists Getting covered Research Basic science research Research in people ... screening Diagnostic testing Direct-to-consumer genetic testing Newborn screening Pharmacogenomic testing ...

  18. Screening for cardiovascular disease before kidney transplantation

    PubMed Central

    Palepu, Sneha; Prasad, G V Ramesh

    2015-01-01

    Pre-kidney transplant cardiac screening has garnered particular attention from guideline committees as an approach to improving post-transplant success. Screening serves two major purposes: To more accurately inform transplant candidates of their risk for a cardiac event before and after the transplant, thereby informing decisions about proceeding with transplantation, and to guide pre-transplant management so that post-transplant success can be maximized. Transplant candidates on dialysis are more likely to be screened for coronary artery disease than those not being considered for transplantation. Thorough history and physical examination taking, resting electrocardiography and echocardiography, exercise stress testing, myocardial perfusion scintigraphy, dobutamine stress echocardiography, cardiac computed tomography, cardiac biomarker measurement, and cardiac magnetic resonance imaging all play contributory roles towards screening for cardiovascular disease before kidney transplantation. In this review, the importance of each of these screening procedures for both coronary artery disease and other forms of cardiac disease are discussed. PMID:26722655

  19. [Unruptured cerebral aneurysms: Controversies on population screening].

    PubMed

    Delgado Lopez, Pedro David; Castilla Díez, José Manuel; Martín Velasco, Vicente

    2016-01-01

    The idea of population screening of unruptured intracranial aneurysms is interesting because, despite recent advances in surgical and endovascular treatment, the mortality related to aneurismal subarachnoid haemorrhage reaches 30%. Screening is justified whenever the morbidity and mortality of the treatment (markedly lower for unruptured compared to ruptured aneurysms) overcomes the inherent risk of harbouring a brain aneurysm. Although, at present, this balance does not seem to favour population-based screening, it is justified in certain sub-populations with an increased risk of rupture. In this review, an analysis is made of the requirements for implementing a screening program, when would it be justified, what is to be expected from treatment (in terms of effectiveness, morbidity and costs), and what medical-legal issues are relevant and to determine the usefulness of the program. A study protocol is proposed aimed at examining the usefulness of population screening for brain aneurysms by magnetic resonance angiography.

  20. RBC Antibody Screen

    MedlinePlus

    ... Cell Antibody Screen Related tests: Direct Antiglobulin Test ; Blood Typing ; RBC Antibody Identification ; Type and Screen; Crossmatch All content on Lab Tests Online has been reviewed and approved by our Editorial Review Board . At a ... screen is used to screen an individual's blood for antibodies directed against red blood cell (RBC) ...

  1. Genotoxic effects of selected biocides on RTG-2 fish cells by means of a modified Fast Micromethod Assay.

    PubMed

    Sánchez-Fortún, S; Llorente, M T; Castaño, A

    2005-06-01

    A sensitive in vitro assay for detecting DNA damage in RTG-2 cells culture is described. This assay employs a dye, PicoGreen double stranded DNA (dsDNA) quantitation reagent, which becomes intensely fluorescent upon binding nucleic acids. The assay includes a simple and rapid 50-min sample lysis in the presence of EDTA, SDS, and high urea concentration at pH 10, followed by time-dependent DNA denaturation at pH 11.6 after NaOH addition. The time course and the extent of DNA denaturation are followed in a microplate fluorescence reader at room temperature for less than 1h. Comparative studies between suspension and fixed RTG-2 cells indicated that it is possible to apply this methodology in both cases with good results. Neutral red assay was used for to determine the cellular viability when RTG-2 cultures were exposed to tetrakis(hydroxymethyl) phosphonium chloride (THPC) and benzalkonium chloride (BC), as biocides used in the disinfection of cooling towers. The results obtained by neutral red assay indicate IC(50(48)) values of 0.017 (0.011-0.028) and 2.71 (1.91-3.86) mg/L for tetrakis(hydroxymethyl) phosphonium chloride and benzalkonium chloride, respectively. DNA damage has been evaluated for both disinfectants in RTG-2 culture, by exposure to 1/10-, 1/25-, 1/50-, and 1/100-IC(50(48)) value, and the results obtained indicate a strain scission factor (SSF) of 0.126+/-0.014, 0.181+/-0.014, 0.217+/-0.013, and 0.245+/-0.013 in cell suspensions, and 0.077+/-0.019, 0.107+/-0.014, 0.151+/-0.014, and 0.202+/-0.015 in attached cells for tetrakis(hydroxymethyl) phosphonium chloride; while the SSF values for benzalkonium chloride are 0.023+/-0.009, 0.033+/-0.017, 0.068+/-0.012, and 0.088+/-0.015 in cell suspensions, and 0.033+/-0.010, 0.044+/-0.011, 0.080+/-0.009, and 0.093+/-0.010 in attached cells. Thus, the assay proposed in this study has made it possible to show DNA damage in RTG-2 cells when exposed to 0.2(1/100 IC(50(48))) and 300(1/10 IC(50(48))) Hg/L of tetrakis

  2. In-Flight Water Quality Monitoring on the International Space Station (ISS): Measuring Biocide Concentrations with Colorimetric Solid Phase Extraction (CSPE)

    NASA Technical Reports Server (NTRS)

    Gazda, Daniel B.; Schultz, John R.; Siperko, Lorraine M.; Porter, Marc D.; Lipert, Robert J.; Flint, Stephanie M.; McCoy, J. Torin

    2011-01-01

    The colorimetric water quality monitoring kit (CWQMK) was delivered to the International Space Station (ISS) on STS-128/17A and was initially deployed in September 2009. The kit was flown as a station development test objective (SDTO) experiment to evaluate the acceptability of colorimetric solid phase extraction (CSPE) technology for routine water quality monitoring on the ISS. During the SDTO experiment, water samples from the U.S. water processor assembly (WPA), the U.S. potable water dispenser (PWD), and the Russian system for dispensing ground-supplied water (SVO-ZV) were collected and analyzed with the CWQMK. Samples from the U.S. segment of the ISS were analyzed for molecular iodine, which is the biocide added to water in the WPA. Samples from the SVOZV system were analyzed for ionic silver, the biocide used on the Russian segment of the ISS. In all, thirteen in-flight analysis sessions were completed as part of the SDTO experiment. This paper provides an overview of the experiment and reports the results obtained with the CWQMK. The forward plan for certifying the CWQMK as operational hardware and expanding the capabilities of the kit are also discussed.

  3. Development and application of a microwave-assisted extraction and LC/MS/MS methodology to the determination of antifouling booster biocides in sea mullets (Mugil cephalus) organisms.

    PubMed

    Franco-Barrios, Alejandro; Torres-Padrón, María Esther; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2014-01-01

    A method is presented for the extraction, preconcentration, and determination of two commonly used booster biocides, Irgarol 1051 and diuron, in samples of muscle and liver tissues from Mugil cephalus by microwave-assisted extraction (MAE) followed by SPE for the preconcentration and cleanup step, coupled with LC/MS/MS. The optimum conditions for MAE were established as power 200 W and irradiation time 4 min. Using these conditions, the LOD was 0.13 ng/g for diuron and 0.10 ng/g for Irgarol 1051. The recoveries calculated at three concentration levels (0.5, 5, and 50 ng/g) were greater than 74%. Repeatability was less than 7.5% and reproducibility less than 12.7%. The optimized method was used to monitor these compounds in M. cephalus from different harbors of Gran Canaria Island. The samples were collected bimonthly and processed following the optimized method. High levels of Irgarol 1051 (6.9 +/- 1.03 ng/g) were found in the liver, while diuron was undetected. However, diuron was found in the muscle (1.41 +/- 0.45 ng/g). The proposed sentinel organism could be used in tropical and subtropical regions to continuously biomonitor for booster biocides over long periods of time. This technique could be a useful tool for improving the management of ocean and coastal waters.

  4. Frequency of biocide-resistant genes and susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA).

    PubMed

    Liu, Qingzhong; Zhao, Huanqiang; Han, Lizhong; Shu, Wen; Wu, Qiong; Ni, Yuxing

    2015-08-01

    The aim of this study was to determine the prevalence of biocide-resistant determinants and the susceptibility to chlorhexidine in high-level mupirocin-resistant, methicillin-resistant Staphylococcus aureus (MuH MRSA). Fifty-three MuH MRSA isolates were analyzed for plasmid-borne genes (qacA/B, smr, qacG, qacH, and qacJ) by polymerase chain reaction (PCR); for chromosome-mediated genes (norA, norB, norC, mepA, mdeA, sepA, and sdrM) by PCR and quantitative reverse transcription-PCR (qRT-PCR); and for susceptibility to chlorhexidine by MIC and minimum bactericidal concentration (MBC). Furthermore, disinfectant efficacy was tested in the presence of 3.0% bovine serum albumin (BSA) in MBC detection. The plasmid-borne genes qacA/B (83.0%) and smr (77.4%) and overexpressions of chromosome-mediated genes norA (49.0%) and norB (28.8%) were predominantly found in isolates studied, and 90.6% of the isolates revealed tolerance to chlorhexidine. In the presence of BSA, the average MBC of chlorhexidine for these isolates rose to 256 μg/mL. Altogether, our results suggest that surveillance of sensitivity to biocides among MuH MRSA isolates is essential for hospital infection control.

  5. Plasma Screen Floating Mount

    DOEpatents

    Eakle, Robert F.; Pak, Donald J.

    2004-10-26

    A mounting system for a flat display screen, particularly a plasma display screen, suspends the screen separately in each of the x-, y- and z-directions. A series of frames located by linear bearings and isolated by springs and dampers allows separate controlled movement in each axis. The system enables the use of relatively larger display screens in vehicles in which plasma screen are subject to damage from vibration.

  6. CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES: Screening influence on the Stark effect of impurity states in strained wurtzite GaN/AlxGa1-xN heterojunctions under pressure

    NASA Astrophysics Data System (ADS)

    Zhang, Min; Ban, Shi-Liang

    2009-12-01

    The screening effect of the random-phase-approximation on the states of shallow donor impurities in free strained wurtzite GaN/AlxGa1-xN heterojunctions under hydrostatic pressure and an external electric field is investigated by using a variational method and a simplified coherent potential approximation. The variations of Stark energy shift with electric field, impurity position, Al component and areal electron density are discussed. Our results show that the screening dramatically reduces both the blue and red shifts as well as the binding energies of impurity states. For a given impurity position, the change in binding energy is more sensitive to the increase in hydrostatic pressure in the presence of the screening effect than that in the absence of the screening effect. The weakening of the blue and red shifts, induced by the screening effect, strengthens gradually with the increase of electric field. Furthermore, the screening effect weakens the mixture crystal effect, thereby influencing the Stark effect. The screening effect strengthens the influence of energy band bending on binding energy due to the areal electron density.

  7. Effect of substituent of terpyridines on the in vitro antioxidant, antitubercular, biocidal and fluorescence studies of copper(II) complexes with clioquinol

    NASA Astrophysics Data System (ADS)

    Kharadi, G. J.

    2014-01-01

    An octahedral complexes of copper with clioquinol(CQ) and substituted terpyridine have been synthesized. The Cu(II) complexes have been characterized by elemental analyses, thermogravimetric analyses, magnetic moment measurements, FT-IR, electronic, 1H NMR and FAB mass spectra. Antimycobacterial screening of ligand and its copper compound against Mycobacterium tuberculosis shows clear enhancement in the antitubercular activity upon copper complexation. Ferric-reducing anti-oxidant power of all complexes were measured. The fluorescence spectra of complexes show red shift, which may be due to the chelation by the ligands to the metal ion. It enhances ligand ability to accept electrons and decreases the electron transition energy. The antimicrobial efficiency of the complexes were tested on five different microorganisms and showed good biological activity.

  8. [Lung cancer screening].

    PubMed

    Sánchez González, M

    2014-01-01

    Lung cancer is a very important disease, curable in early stages. There have been trials trying to show the utility of chest x-ray or computed tomography in Lung Cancer Screening for decades. In 2011, National Lung Screening Trial results were published, showing a 20% reduction in lung cancer mortality in patients with low dose computed tomography screened for three years. These results are very promising and several scientific societies have included lung cancer screening in their guidelines. Nevertheless we have to be aware of lung cancer screening risks, such as: overdiagnosis, radiation and false positive results. Moreover, there are many issues to be solved, including choosing the appropriate group to be screened, the duration of the screening program, intervals between screening and its cost-effectiveness. Ongoing trials will probably answer some of these questions. This article reviews the current evidence on lung cancer screening.

  9. Regenerable biocide delivery unit

    NASA Technical Reports Server (NTRS)

    Sauer, Richard L. (Inventor); Colombo, Gerald V. (Inventor); Jolly, Clifford D. (Inventor)

    1993-01-01

    A method and apparatus are disclosed for maintaining continuous, long-term microbial control in the water supply for potable, hygiene, and experimental water for space activities, as well as treatment of water supplies on Earth. The water purification is accomplished by introduction of molecular iodine into the water supply to impart a desired iodine residual. The water is passed through an iodinated anion exchange resin bed. The iodine is bound as I-(sub n) at the anion exchange sites and releases I(sub 2) into the water stream flowing through the bed. The concentration of I(sub 2) in the flowing water gradually decreases and, in the prior art, the ion-exchange bed has had to be replaced. In a preferred embodiment, a bed of iodine crystals is provided with connections for flowing water therethrough to produce a concentrated (substantially saturated) aqueous iodine solution which is passed through the iodinated resin bed to recharge the bed with bound iodine. The bed of iodine crystals is connected in parallel with the iodinated resin bed and is activated periodically (e.g., by timer, by measured flow of water, or by iodine residual level) to recharge the bed. Novelty resides in the capability of inexpensively and repeatedly regenerating the ion-exchange bed in situ.

  10. Superb hydroxyl radical-mediated biocidal effect induced antibacterial activity of tuned ZnO/chitosan type II heterostructure under dark

    NASA Astrophysics Data System (ADS)

    Podder, Soumik; Halder, Suman; Roychowdhury, Anirban; Das, Dipankar; Ghosh, Chandan Kr.

    2016-10-01

    Reactive oxygen species (ROS) is the most dominating factor for bacteria cell toxicity due to release of oxidative stress. Hydroxyl radical (·OH) is a strong oxidizing ROS that has high impact on biocidal activity. This present paper highlights ·OH influenced antibacterial activity and biocidal propensity of tuned ZnO/chitosan (ZnO/CS) nanocomposite against Pseudomonas putida (P. putida) in the absence of light for the first time. For this purpose, the CS proportion was increased by 25 % (w/w) of ZnO during the preparation of ZnO/CS nanocomposite and a systematic study of different ROS like superoxide anion (O 2 ·- ), hydrogen peroxide (H2O2) and ·OH production as well as their kinetics was carried out both under UV irradiation and in dark by UV-Vis spectroscopy using NBT dye, starch and iodine reaction and fluorescence spectroscopy using terephthalic acid. The decoration of ZnO nanoparticles (ZnO·NPs) with CS tuning was characterized by XRD and FTIR spectroscopy, revealing sustained crystallinity and surface coating of ZnO NP (size about 24 nm) by CS molecule. The hybridization of ZnO nanoparticles with CS@50 wt% (w/w) resulted superior biocidal activity (81 %) within 3 h in dark mediated by optimum production of ·OH among all ROS. Here we have proposed the enhanced production of ·OH in ZnO/CS due to generation of holes by entrapment of electrons in acceptor level formed in nanocomposite for the first time, and the acceptor levels were probed by Positron annihilation lifetime spectroscopy. The increase in non-positronium (non-Ps) formation probability (I2) in ZnO/CS nanocomposite confirmed the acceptor levels. This work also confirms surface defect-mediated ROS generation in dark, and zinc interstitials are proposed as active defect sites for generation of holes and ·OH for the first time and confirmed by steady-state room temperature photoluminescence spectroscopy. Finally, a plausible mechanism was hypothesized focusing on hole generation in ZnO NP and

  11. Stretching Screens and Imaginations.

    ERIC Educational Resources Information Center

    Douthwaite, Shelaugh

    1983-01-01

    Secondary students utilize a simplified technique to make silk screen prints, which can be printed onto T-shirts. The only materials needed from art suppliers are a few squeegees and a few yards of polyester screen mesh. (RM)

  12. Screening Tests and Vaccines

    MedlinePlus

    ... Contact Us Text size | Print | Screening Tests and Vaccines This information in Spanish ( en español ) Getting important screening tests and vaccines can save your life. Check this section of ...

  13. Cancer Screening Overview (PDQ)

    MedlinePlus

    ... is important that you understand the benefits and harms of screening tests and make an informed choice ... provider . Every screening test has both benefits and harms. Your health care provider should talk to you ...

  14. Screening for VHL

    MedlinePlus

    ... reduce the most harmful consequences of this gene mutation. It is important to diagnose and begin screening ... to determine if a child has a VHL mutation and needs to follow the recommended screening. The ...

  15. Video Screen Capture Basics

    ERIC Educational Resources Information Center

    Dunbar, Laura

    2014-01-01

    This article is an introduction to video screen capture. Basic information of two software programs, QuickTime for Mac and BlueBerry Flashback Express for PC, are also discussed. Practical applications for video screen capture are given.

  16. Lung cancer screening.

    PubMed

    Tanoue, Lynn T; Tanner, Nichole T; Gould, Michael K; Silvestri, Gerard A

    2015-01-01

    The United States Preventive Services Task Force recommends lung cancer screening with low-dose computed tomography (LDCT) in adults of age 55 to 80 years who have a 30 pack-year smoking history and are currently smoking or have quit within the past 15 years. This recommendation is largely based on the findings of the National Lung Screening Trial. Both policy-level and clinical decision-making about LDCT screening must consider the potential benefits of screening (reduced mortality from lung cancer) and possible harms. Effective screening requires an appreciation that screening should be limited to individuals at high risk of death from lung cancer, and that the risk of harm related to false positive findings, overdiagnosis, and unnecessary invasive testing is real. A comprehensive understanding of these aspects of screening will inform appropriate implementation, with the objective that an evidence-based and systematic approach to screening will help to reduce the enormous mortality burden of lung cancer.

  17. Standard Printing Screen System.

    DTIC Science & Technology

    area pattern screens. It also describes the creation of a 100-step continuous growth halftone scale for the purpose of specifying quality control tolerances of screen tints for the printed product. (Author)

  18. Newborn Screening Tests Approved

    MedlinePlus

    ... The screens are used to detect four rare metabolic disorders To use the sharing features on this page, ... of screening tests designed to detect four rare metabolic disorders in newborns has been approved by the U.S. ...

  19. Liver (Hepatocellular) Cancer Screening

    MedlinePlus

    ... Treatment Liver Cancer Prevention Liver Cancer Screening Research Liver (Hepatocellular) Cancer Screening (PDQ®)–Patient Version What is ... These are called diagnostic tests . General Information About Liver (Hepatocellular) Cancer Key Points Liver cancer is a ...

  20. Magnetically leviated superconducting bearing

    DOEpatents

    Weinberger, Bernard R.; Lynds, Jr., Lahmer

    1993-01-01

    A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.

  1. Fabrication of magnetic nanoparticles armed with quaternarized N-halamine polymers as recyclable antibacterial agents.

    PubMed

    Wang, Xi; Xiang, Qian; Cao, Weiwei; Jin, Feng; Peng, Xuefeng; Hu, Bingcheng; Xing, Xiaodong

    2016-10-04

    Magnetic recyclable bactericidal nanocomposites (Fe3O4@PDMC) were well-designed and prepared by coating of Fe3O4 nanoparticles with quaternarized N-halamine polymers via the free radical polymerization process. In which, 5,5-dimethylhydantoinyl-(3-ethyl-methacrylamine)propyl dimethylammonium bromide (DEMPA), a new monomeric N-halamine precursor, was used as a coating material as well as the dual-functional bactericidal agent. The developed Fe3O4@PDMC nanocomposites exhibited suitable size and super-paramagnetic responsibility. The antibacterial results showed that the Fe3O4@PDMC nanocomposites had excellent biocidal abilities against Staphylococcus aureus (gram-positive) and Escherichia coli (gram-negative). Furthermore, the TTC (Triphenyl Tetrazolium Chloride)-dehydrogenase activity assay confirmed that the reductions of the bacteria were mainly attributed to powerful biocidal effects of the coating polymer instead of bacteria capture by the cationic surface. Interestingly, due to the magnetic responsive performance of Fe3O4, the as-prepared Fe3O4@PDMC nanocomposites can be recycled by a magnet and reused for antibacterium through the quenching/rechlorination procedure. All the results presented in this study show that the proposed Fe3O4@PDMC nanocomposites could be a competitive candidate for water purification systems and household sanitation.

  2. Neonatal cystic fibrosis screening test

    MedlinePlus

    Cystic fibrosis screening - neonatal; Immunoreactive trypsinogen; IRT test; CF - screening ... better nutrition, growth, and lung function. This screening test helps doctors identify children with CF before they ...

  3. Medicare Preventive and Screening Services

    MedlinePlus

    ... B (Medical Insurance) covers: Abdominal aortic aneurysm screening Alcohol misuse screenings & counseling Bone mass measurements (bone density) Cardiovascular disease screenings Cardiovascular disease (behavioral therapy) Cervical & ...

  4. Breast awareness and screening.

    PubMed

    Harmer, Victoria

    Breast cancer is the most commonly diagnosed cancer in the UK. Breast awareness and screening, along with better treatment, can significantly improve outcomes, and more women than ever are now surviving the disease. This article discusses breast awareness and screening, symptoms and risk factors for breast cancer, and how nurses can raise breast awareness and screening uptake.

  5. Principles of Cancer Screening.

    PubMed

    Pinsky, Paul F

    2015-10-01

    Cancer screening has long been an important component of the struggle to reduce the burden of morbidity and mortality from cancer. Notwithstanding this history, many aspects of cancer screening remain poorly understood. This article presents a summary of basic principles of cancer screening that are relevant for researchers, clinicians, and public health officials alike.

  6. Screen time and children

    MedlinePlus

    ... obesity ) Screen time increases your child's risk of obesity because: Sitting and watching a screen is time that is not spent being physically active. TV commercials and other screen ads can lead to unhealthy food choices . Most of the time, the foods in ads ...

  7. Cancer Screening: How Do Screening Tests Become Standard Tests?

    MedlinePlus

    ... cancer symptoms. There are different kinds of screening tests. Screening tests include the following: Physical exam and ... are linked to some types of cancer. Screening tests have risks. Not all screening tests are helpful ...

  8. Ecotoxicological evaluation of the biocidal agents sodium o-phenylphenol, sodium o-benzyl-p-chlorophenol, and sodium p-tertiary amylphenol.

    PubMed

    Davoren, M; Fogarty, A M

    2005-02-01

    The ecotoxicological effects of three biocidal agents frequently employed as active ingredients in phenolic-based disinfectants were evaluated using a test battery comprising of organisms representing three aquatic trophic levels. Phenolic-based disinfectants are commonly used by mushroom growers to disinfect spent mushroom compost. In general, the most sensitive assay used in this study was the Microtox test. In the case of the fish lethality assay, sodium o-benzyl-p-chlorophenol was found to be slightly more sensitive than the bacterial test system. The freshwater alga and invertebrate tests were also among the most sensitive test species employed. The active ingredient, sodium o-benzyl-p-chlorophenol (with the exception of the Microtox assay), was the most toxic chemical tested on each species. The majority of ecotoxicity data obtained in this research has not been previously reported and may therefore assist in the management and planning decisions regarding the application of pesticides and utilisation of SMC.

  9. Powder characteristics and biocidal activity of the MnOx-WO₃-TiO₂ system synthesized by a sol-gel method for antifouling agents.

    PubMed

    Shin, Byeongkil; Kim, Sangmin; Lee, Heesoo; Park, Hyun

    2013-08-01

    The TiO₂-system powders were investigated with respect to the crystallinity and the microstructure. The biocidal activity increased from TiO₂ to binary MnOx-TiO₂ to ternary MnOx-WO₃-TiO₂ against Vibrio fischeri as a model of Gram-negative bacteria. Anatase and rutile TiO₂ were not toxic even at 200 mg/L, but anatase has been observed in bacterial growth inhibition due to the different electronic band (lattice) structure. All materials containing manganese oxides were toxic: the toxicity correlation (EC₅₀) of MnOx-WO₃ and MnOx-WO₃-TiO₂ was 7.0, 1.8 ppm, respectively. The high antifouling activity of MnOx-WO₃-TiO₂ was attributed to its redox potential and soluble metal ions originating from tungsten oxides according to the improvements in the powder characteristics.

  10. Acupressure magnets: a possible MRI hazard.

    PubMed

    Otjen, Jeffrey P; Mallon, Kara; Brown, Julie C

    2015-03-01

    The use of magnets as a component of complementary and alternative medicine is increasingly common. Magnet therapy is used to treat a variety of conditions and often involves tiny magnets adhered to the skin. In auriculotherapy, magnets are placed in specific locations of the ear pinnae which represent particular parts of the body. While generally considered safe, these magnets have the potential to cause imaging problems and serious injury during MRI. We report a case of auriculotherapy magnets which escaped detection despite the use of screening forms and a walk-through metal detector. The magnets caused image artifact but no other patient harm. We recommend updating patient screening practices and educating providers placing therapeutic magnets and performing MRIs of this new potential MRI hazard.

  11. [Colorectal cancer screening].

    PubMed

    Castells, Antoni

    2015-09-01

    Colorectal cancer is one of malignancies showing the greatest benefit from preventive measures, especially screening or secondary prevention. Several screening strategies are available with demonstrated efficacy and efficiency. The most widely used are the faecal occult blood test in countries with population-based screening programmes, and colonoscopy in those conducting opportunistic screening. The present article reviews the most important presentations on colorectal cancer screening at the annual congress of the American Gastroenterological Association held in Washington in 2015, with special emphasis on the medium-term results of faecal occult blood testing strategies and determining factors and on strategies to reduce the development of interval cancer after colonoscopy.

  12. Newborn screening: current status.

    PubMed

    Arn, Pamela H

    2007-01-01

    Newborn screening, which represents one of the major advances in child health of the past century, has been carried out in all fifty U.S. states since the 1970s. Newborn screening programs are state-run, and decisions are left to the individual states regarding the conditions to be screened for, the mechanism for confirmatory testing, follow-up care, and financing of the programs. Laboratory advances in tandem mass spectrometry make it possible to screen newborns for many rare inborn errors of metabolism. This raises many policy issues including screening's cost-effectiveness, ethics, quality, and oversight.

  13. Monitoring the performance of innovative and traditional biocides mixed with consolidants and water-repellents for the prevention of biological growth on stone.

    PubMed

    Pinna, Daniela; Salvadori, Barbara; Galeotti, Monica

    2012-04-15

    In this study, some mixtures of consolidants or water-repellent products and biocides developed to prevent biological growth, were tested over time on three stone substrates with different bioreceptivity. The performance of both traditional (tetraethylorthosilicate, methylethoxy polysiloxane, Paraloid B72, tributyltin oxide, dibutyltin dilaurate) and innovative compounds (copper nanoparticles) was assessed using colour measurements, the water absorption by contact sponge method, and observation under stereo and optical microscopes. The application of the mixtures had also the purpose of controlling re-colonization on stone after a conservation treatment. The study site was the archaeological Area of Fiesole; the mixtures were applied in situ to sandstone, marble and plaster which had been cleaned beforehand. An innovative aspect of the study is that, by using non-invasive methods, it also permitted monitoring the mixtures' effectiveness in preventing biological growth. The monitoring results made it possible to assess the bioreceptivity of the treated stones (sandstone, marble, plaster) over a period of almost three years. The results showed that the mixtures of consolidants or water-repellent products with biocides were effective in preventing biological growth on both a substrate with low bioreceptivity like plaster and a substrate with high bioreceptivity such as marble. The innovative mixture of nano-Cu particles with a water-repellent yielded good results in terms of preventing biological colonization. Moreover, they apparently did not affect the substrates' colour. Mixtures of nano-Cu particles with a consolidant and a water-repellent hold great promise for preventing re-colonization of stone after conservation treatment.

  14. Antagonistic activity of Bacillus sp. obtained from an Algerian oilfield and chemical biocide THPS against sulfate-reducing bacteria consortium inducing corrosion in the oil industry.

    PubMed

    Gana, Mohamed Lamine; Kebbouche-Gana, Salima; Touzi, Abdelkader; Zorgani, Mohamed Amine; Pauss, André; Lounici, Hakim; Mameri, Nabil

    2011-03-01

    The present study enlightens the role of the antagonistic potential of nonpathogenic strain B21 against sulfate-reducing bacteria (SRB) consortium. The inhibitor effects of strain B21 were compared with those of the chemical biocide tetrakishydroxymethylphosphonium sulfate (THPS), generally used in the petroleum industry. The biological inhibitor exhibited much better and effective performance. Growth of SRB in coculture with bacteria strain B21 antagonist exhibited decline in SRB growth, reduction in production of sulfides, with consumption of sulfate. The observed effect seems more important in comparison with the effect caused by the tested biocide (THPS). Strain B21, a dominant facultative aerobic species, has salt growth requirement always above 5% (w/v) salts with optimal concentration of 10-15%. Phylogenetic analysis based on partial 16S rRNA gene sequences showed that strain B21 is a member of the genus Bacillus, being most closely related to Bacillus qingdaonensis DQ115802 (94.0% sequence similarity), Bacillus aidingensis DQ504377 (94.0%), and Bacillus salarius AY667494 (92.2%). Comparative analysis of partial 16S rRNA gene sequence data plus physiological, biochemical, and phenotypic features of the novel isolate and related species of Bacillus indicated that strain B21 may represent a novel species within the genus Bacillus, named Bacillus sp. (EMBL, FR671419). The results of this study indicate the application potential of Bacillus strain B21 as a biocontrol agent to fight corrosion in the oil industry.

  15. Degradation of the biocide 4-chloro-3,5-dimethylphenol in aqueous medium with ozone in combination with ultraviolet irradiation: operating conditions influence and mechanism.

    PubMed

    Song, Shuang; Liu, Zhiwu; He, Zhiqiao; Li, Yu; Chen, Jianmeng; Li, Chaolin

    2009-11-01

    Biocides usually persist during municipal sewage treatment and are subsequently distributed into aquatic environments. To explore the capability of advanced oxidation processes for the rapid removal of biocides, we examined the total organic carbon (TOC) reduction of 4-chloro-3,5-dimethylphenol (PCMX) with a combination of UV/O(3). Moreover, the related important parameters, including the mass transfer coefficient and light utilization efficiency, in PCMX degradation were determined. The UV/O(3) experimental results showed a pronounced synergistic effect, leading to the nearly complete elimination of TOC within 75 min. Thus, the effect of operating variables was investigated as a function of pH, ozone dosage, bulk temperature and the initial concentration of PCMX. The efficiency of PCMX mineralization increased with an increase in ozone dose up to 3.1 gh(-1), and a decrease in the initial concentration from 250 to 100mg L(-1). The optimal pH value was 4.0, and the preferred bulk temperature was 20 degrees C on the basis of the influence of temperature on reaction rate and ozone solubility. The major aromatic intermediates identified by gas chromatography/mass spectrometry were 2,6-dimethylbenzene-1,4-diol, 2,6-dimethylbenzo-1,4-quinone, 2,6-bis(hydroxymethyl)benzo-1,4-quinone, and 2,6-dimethylbenzo-1,4-aldehyde. Quantitative determination of related carboxylic acid and inorganic anions was done by ion chromatography. On the basis of the identified reaction products, a possible degradation pathway for the UV/O(3) oxidation of PCMX in aqueous media is proposed.

  16. Characterization and quantification of N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine biocide by NMR, HPLC/MS and titration techniques.

    PubMed

    Mondin, Andrea; Bogialli, Sara; Venzo, Alfonso; Favaro, Gabriella; Badocco, Denis; Pastore, Paolo

    2014-01-01

    The present paper reports the determination of the tri-amine N-(3-aminopropyl)-N-dodecyl-1,3-propanediamine (TA) present in a raw material called LONZABAC used to formulate various, widely used commercial biocides. The active principle, TA, is present in LONZABAC together with other molecules at lower concentration levels. Three independent analytical approaches, namely solution NMR spectroscopy, liquid chromatography coupled to high resolution mass spectrometry (LC/HRMS) and acid-base titration in mixed solvent, were used to overcome the problem of the non-availability of the active principle as high purity standard. NMR analysis of raw material, using a suitable internal standard, evidenced in all analyzed lots the presence of the active principle, the N-dodecyl-1,3-propanediamine (DA) and the n-dodecylamine (MA) and the absence of non-organic, NMR-inactive species. NMR peak integration led to a rough composition of the MA:DA:TA as 1:9:90. The LC/HRMS analysis allowed the accurate determination of DA and MA and confirmed in all samples the presence of the TA, which was estimated by difference: MA=1.4±0.3%, DA=11.1±0.7%, TA=87.5±1.3%. The obtained results were used to setup an easy, rapid and cheap acid-base titration method able to furnish a sufficiently accurate evaluation of the active principle both in the raw material and in diluted commercial products. For the raw material the results were: TA+MA=91.1±0.8% and DA-MA=8.9±0.8%, statistically coherent with LC/MS ones. The LC/MS approach demonstrated also its great potentialities to recognize trace of the biocide components both in environmental samples and in the formulated commercial products.

  17. Magnetic impedance biosensor: A review.

    PubMed

    Wang, Tao; Zhou, Yong; Lei, Chong; Luo, Jun; Xie, Shaorong; Pu, Huayan

    2017-04-15

    Though the magnetoimpedance effect was discovered two decades ago, the biomedical applications of the magnetoimpedance sensor are still in their infancy. In this review, the authors summarized the magnetoimpedance effect in soft ferromagnetic wires, ribbons and thin films for biosensing applications. Recent progress and achievements of the magnetoimpedance-based biosensing applications including the detection of magnetic Ferrofluid, magnetic beads, magnetic nanoparticles, magnetically labeled bioanalytes and biomagnetic fields of living systems were reviewed. The modification effect of the biochemical liquids, agglomeration effect of the magnetic particles, and the effect of the stray magnetic field on magnetoimpedance were investigated in this review. Some constructive strategies were proposed for design of the high-performance magnetoimpedance biosensor, for quantitative and ultrasensitive detection of magnetically labeled biomolecules. The theoretical and experimental results suggest that the magnetoimpedance sensors are particularly suitable for highly sensitive detection of low-concentration biomolecules, and might be used for early diagnosis and screening of cancers.

  18. Lung Cancer Screening Update.

    PubMed

    Ruchalski, Kathleen L; Brown, Kathleen

    2016-07-01

    Since the release of the US Preventive Services Task Force and Centers for Medicare and Medicaid Services recommendations for lung cancer screening, low-dose chest computed tomography screening has moved from the research arena to clinical practice. Lung cancer screening programs must reach beyond image acquisition and interpretation and engage in a multidisciplinary effort of clinical shared decision-making, standardization of imaging and nodule management, smoking cessation, and patient follow-up. Standardization of radiologic reports and nodule management will systematize patient care, provide quality assurance, further reduce harm, and contain health care costs. Although the National Lung Screening Trial results and eligibility criteria of a heavy smoking history are the foundation for the standard guidelines for low-dose chest computed tomography screening in the United States, currently only 27% of patients diagnosed with lung cancer would meet US lung cancer screening recommendations. Current and future efforts must be directed to better delineate those patients who would most benefit from screening and to ensure that the benefits of screening reach all socioeconomic strata and racial and ethnic minorities. Further optimization of lung cancer screening program design and patient eligibility will assure that lung cancer screening benefits will outweigh the potential risks to our patients.

  19. Automated Groundwater Screening

    SciTech Connect

    Taylor, Glenn A.; Collard, Leonard, B.

    2005-10-31

    The Automated Intruder Analysis has been extended to include an Automated Ground Water Screening option. This option screens 825 radionuclides while rigorously applying the National Council on Radiation Protection (NCRP) methodology. An extension to that methodology is presented to give a more realistic screening factor for those radionuclides which have significant daughters. The extension has the promise of reducing the number of radionuclides which must be tracked by the customer. By combining the Automated Intruder Analysis with the Automated Groundwater Screening a consistent set of assumptions and databases is used. A method is proposed to eliminate trigger values by performing rigorous calculation of the screening factor thereby reducing the number of radionuclides sent to further analysis. Using the same problem definitions as in previous groundwater screenings, the automated groundwater screening found one additional nuclide, Ge-68, which failed the screening. It also found that 18 of the 57 radionuclides contained in NCRP Table 3.1 failed the screening. This report describes the automated groundwater screening computer application.

  20. Cervical cancer screening.

    PubMed Central

    Katz, A.

    1998-01-01

    OBJECTIVE: To review the role of family physicians in screening for cancer of the cervix, to review the evidence for screening, in particular, frequency and technique for screening, and to review the reasons cervical cancer has not been prevented and the role of family physicians in addressing these failures. QUALITY OF EVIDENCE: The value of screening has been established with level II evidence. Many of the unresolved issues are not supported either way by good evidence; level II and III evidence predominates. MAIN FINDINGS: In Canada, 1350 women were predicted to be diagnosed with cancer of the cervix in 1996. Most of these women had not been screened. Minority, rural, low-income, and older women face important barriers to screening. Family physicians have a role in reaching out to these women to provide effective health care, including cancer screening. When cancer screening is performed, it should conform to recommended techniques with appropriate follow up of abnormal test results. CONCLUSIONS: Family physicians have an important role in preventing cancer of the cervix. Efforts should be concentrated on encouraging a greater proportion of eligible women to be screened. Criteria are suggested for effective screening. PMID:9721422

  1. Screening in liver disease

    PubMed Central

    Poggio, Paolo Del; Mazzoleni, Marzio

    2006-01-01

    A disease is suitable for screening if it is common, if the target population can be identified and reached and if both a good screening test and an effective therapy are available. Of the most common liver diseases only viral hepatitis and genetic hemochromatosis partially satisfy these conditions. Hepatitis C is common, the screening test is good and the therapy eliminates the virus in half of the cases, but problems arise in the definition of the target population. In fact generalized population screening is not endorsed by international guidelines, although some recommend screening immigrants from high prevalence countries. Opportunistic screening (case finding) of individuals with classic risk factors, such as transfusion before 1992 and drug addiction, is the most frequently used strategy, but there is disagreement whether prison inmates, individuals with a history of promiscuous or traumatic sex and health care workers should be screened. In a real practice setting the performance of opportunistic screening by general practitioners is low but can be ameliorated by training programs. Screening targeted to segments of the population or mass campaigns are expensive and therefore interventions should be aimed to improve opportunistic screening and the detection skills of general practitioners. Regarding genetic hemochromatosis there is insufficient evidence for population screening, but individual physicians can decide to screen racial groups with a high prevalence of the disease, such as people in early middle age and of northern European origin. In the other cases opportunistic screening of high risk individuals should be performed, with a high level of suspicion in case of unexplained liver disease, diabetes, juvenile artropathy, sexual dysfunction and skin pigmentation. PMID:16981254

  2. Screening on binary Zr-1X (X = Ti, Nb, Mo, Cu, Au, Pd, Ag, Ru, Hf and Bi) alloys with good in vitro cytocompatibility and magnetic resonance imaging compatibility.

    PubMed

    Zhou, F Y; Qiu, K J; Li, H F; Huang, T; Wang, B L; Li, L; Zheng, Y F

    2013-12-01

    In this study, the microstructures, mechanical properties, corrosion behaviors, in vitro cytocompatibility and magnetic susceptibility of Zr-1X alloys with various alloying elements, including Ti, Nb, Mo, Cu, Au, Pd, Ag, Ru, Hf and Bi, were systematically investigated to explore their potential use in biomedical applications. The experimental results indicated that annealed Zr-1X alloys consisted entirely or primarily of α phase. The alloying elements significantly increased the strength and hardness of pure Zr and had a relatively slight influence on elastic modulus. Ru was the most effective enhancing element and Zr-1Ru alloy had the largest elongation. The results of electrochemical corrosion indicated that adding various elements to Zr improved its corrosion resistance, as indicated by the reduced corrosion current density. The extracts of the studied Zr-1X alloys produced no significant deleterious effects on osteoblast-like cells (MG 63), indicating good in vitro cytocompatibility. All except for Zr-1Ag alloy showed decreased magnetic susceptibility compared to pure Zr, and Zr-1Ru alloy had the lowest magnetic susceptibility value, being comparable to that of α' phase Zr-Mo alloy and Zr-Nb alloy and far lower than that of Co-Cr alloy and Ti-6Al-4V alloy. Among the experimental Zr-1X alloys, Zr-1Ru alloy possessing high strength coupled with good ductility, good in vitro cytocompatibility and low magnetic susceptibility may be a good candidate alloy for medical devices within a magnetic resonance imaging environment.

  3. Turbulent flow through screens

    NASA Technical Reports Server (NTRS)

    Mehta, R. D.

    1984-01-01

    A detailed experimental investigation has been carried out on the effects of different types of screens on turbulent flow, in particular turbulent boundary layers. The effect of a screen on a turbulent boundary layer is to give it a 'new lease of life'. The boundary layer turbulence is reorganized and the thickness reduced, thus making it less susceptible to separation. The aerodynamic properties of plastic screens are found to differ significantly from those of the conventional metal screens, evidently because of differences in the weaving properties. The 'overshoot' in mean velocity profile near the boudnary layer edge is shown to be a result of the effect of screen inclination on pressure drop coefficient. A more accurate formulation for the deflection coefficient of a screen is also proposed.

  4. Screening of lake sediments for emerging contaminants by liquid chromatography atmospheric pressure photoionization and electrospray ionization coupled to high resolution mass spectrometry.

    PubMed

    Chiaia-Hernandez, Aurea C; Krauss, Martin; Hollender, Juliane

    2013-01-15

    We developed a multiresidue method for the target and suspect screening of more than 180 pharmaceuticals, personal care products, pesticides, biocides, additives, corrosion inhibitors, musk fragrances, UV light stabilizers, and industrial chemicals in sediments. Sediment samples were freeze-dried, extracted by pressurized liquid extraction, and cleaned up by liquid-liquid partitioning. The quantification and identification of target compounds with a broad range of physicochemical properties (log K(ow) 0-12) was carried out by liquid chromatography followed by electrospray ionization (ESI) and atmospheric pressure photoionization (APPI) coupled to high resolution Orbitrap mass spectrometry (HRMS/MS). The overall method average recoveries and precision are 103% and 9% (RSD), respectively. The method detection limits range from 0.010 to 4 ng/g(dw), while limits of quantification range from 0.030 to 14 ng/g(dw). The use of APPI as an alternative ionization source helped to distinguish two isomeric musk fragrances by means of different ionization behavior. The method was demonstrated on sediment cores from Lake Greifensee located in northeastern Switzerland. The results show that biocides, musk fragrances, and other personal care products were the most frequently detected compounds with concentrations ranging from pg/g(dw) to ng/g(dw), whereas none of the targeted pharmaceuticals were found. The concentrations of many urban contaminants originating from wastewater correlate with the highest phosphorus input into the lake as a proxy for treatment efficiency. HRMS enabled a retrospective analysis of the full-scan data acquisition allowing the detection of suspected compounds like quaternary ammonium surfactants, the biocide triclocarban, and the tentative identification of further compounds without reference standards, among others transformation products of triclosan and triclocarban.

  5. Chlamydia Screening Decision Study

    DTIC Science & Technology

    2000-05-01

    uncomplicated chlamydia infection can be treated with an inexpensive course of oral antibiotics taken on an outpatient basis, while pelvic inflammatory disease... contraception , I would screen for chlamydia . Chlamydia Screening 31 I would say intuition doesn’t play into my decision making because there are high risk...or inconsistent barrier contraception Chlamydia Screening 34 practice. This view was not supported by the data obtained from the review of patient

  6. Composite scintillator screen

    DOEpatents

    Zeman, Herbert D.

    1994-01-01

    A scintillator screen for an X-ray system includes a substrate of low-Z material and bodies of a high-Z material embedded within the substrate. By preselecting the size of the bodies embedded within the substrate, the spacial separation of the bodies and the thickness of the screen, the sensitivity of the screen to X-rays within a predetermined energy range can be predicted.

  7. Human Papillomavirus (HPV) Screening

    MedlinePlus

    ... and Answers HPV and Cancer HPV Cancer Screening HPV Vaccines HPV Vaccine Safety For Clinicians Why is HPV Vaccine Important Clinician Factsheets Schedules & Recommendations Answering Parents Questions ...

  8. Colorectal cancer screening

    PubMed Central

    Chan, Pak Wo Webber; Ngu, Jing Hieng; Poh, Zhongxian; Soetikno, Roy

    2017-01-01

    Colorectal cancer, which is the leading cancer in Singapore, can be prevented by increased use of screening and polypectomy. A range of screening strategies such as stool-based tests, flexible sigmoidoscopy, colonoscopy and computed tomography colonography are available, each with different strengths and limitations. Primary care physicians should discuss appropriate screening modalities with their patients, tailored to their individual needs. Physicians, patients and the government should work in partnership to improve uptake of colorectal cancer screening to reduce the morbidity and mortality from colorectal cancer. PMID:28111691

  9. Testicular Cancer Screening

    MedlinePlus

    ... Laboratory for Cancer Research Partners & Collaborators Spotlight on Scientists Research Areas Cancer Biology Cancer Genomics Causes of Cancer Diagnosis Prevention Screening & Early Detection Treatment Cancer & Public Health ...

  10. [Overdiagnosis in cancer screening].

    PubMed

    Cervera Deval, J; Sentís Crivillé, M; Zulueta, J J

    2015-01-01

    In screening programs, overdiagnosis is defined as the detection of a disease that would have gone undetected without screening when that disease would not have resulted in morbimortality and was treated unnecessarily. Overdiagnosis is a bias inherent in screening and an undesired effect of secondary prevention and improved sensitivity of diagnostic techniques. It is difficult to discriminate a priori between clinically relevant diagnoses and those in which treatment is unnecessary. To minimize the effects of overdiagnosis, screening should be done in patients at risk.

  11. Screening for colorectal cancer.

    PubMed

    Mandel, Jack S

    2008-03-01

    Although there are several methods available for colon cancer screening, none is optimal. This article reviews methods for screening, including fecal occult blood tests, flexible sigmoidoscopy, colonoscopy, CT colonography, capsule endoscopy, and double contrast barium enema. A simple, inexpensive, noninvasive, and relatively sensitive screening test is needed to identify people at risk for developing advanced adenomas or colorectal cancer who would benefit from colonoscopy. It is hoped that new markers will be identified that perform better. Until then we fortunately have a variety of screening strategies that do work.

  12. Intagliated phosphor screen image tube project

    NASA Technical Reports Server (NTRS)

    Hertzel, R. J.

    1982-01-01

    The production and evaluation of a magnetic focus image tube for astronomical photography that has an intagliated phosphor screen is described. The modulation transfer function of such a tube was measured by electronic means and by film tests, and the results compared with tubes of more conventional construction. The physical properties of the image tube and film combination, the analytical model of the optical interface, and the salient features of the intagliated screen tube are described. The results of electronic MTF tests of the intagliated image tube and of the densitometry of the tube and film test samples are presented. It is concluded that the intagliated screen is a help, but that the thickness of the photographic film is also important.

  13. Breast cancer screening and biomarkers.

    PubMed

    Brooks, Mai

    2009-01-01

    Annual screening mammograms have been shown to be cost-effective and are credited for the decline in mortality of breast cancer. New technologies including breast magnetic resonance imaging (MRI) may further improve early breast cancer detection in asymptomatic women. Serum tumor markers such as CA 15-3, carcinoembyonic antigen (CEA), and CA 27-29 are ordered in the clinic mainly for disease surveillance, and not useful for detection of localized cancer. This review will discuss blood-based markers and breast-based markers, such as nipple/ductal fluid, with an emphasis on biomarkers for early detection of breast cancer. In the future, it is likely that a combination approach to simultaneously measure multiple markers would be most successful in detecting early breast cancer. Ideally, such a biomarker panel should be able to detect breast cancer in asymptomatic patients, even in the setting of normal mammogram and physical examination results.

  14. Scoliosis Screening in Schools.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Div. of Pupil Personnel Services.

    The booklet outlines New York state school policy and procedures for screening students for scoliosis, lateral curvature of the spine. It is explained that screening is designed to discover spinal deformities early enough to prevent surgery. Planning aspects, including organizing a planning team for the school district, are discussed. Among…

  15. Screening: the legal view.

    PubMed

    Eaden, J; Mayberry, M K; Sherr, A; Mayberry, J F

    2001-05-01

    Screening has become central to the effective prevention of several diseases, but implementation suffers from difficulties with targeting and rates of compliance. Such issues are also complicated by the need to consider legal provisions regarding confidentiality of patients and other human rights issues. Screening has been an inexact science in relation to, e.g., faecal occult blood testing for colorectal cancer, false positive and false negative tests for HIV, and there have been inadequate quality controls in breast cancer screening programmes. The public need to be made aware of what the screening programmes really offer, balanced against the expectations they may have. There needs to be a clearer understanding of the nature of the contractual and other legal rights of patients/consumers as against providers. A positive screening test may carry adverse consequences as well as benefits. It could alert an insurance company to a risk and lead to additional weighting or even outright rejection for life insurance policies. Job prospects may also be affected for employees. The method of informing patients in relation to screening and screening failure has already been considered by the courts. Realistic information about both screening and treatment efficiency needs to be offered to patients so that they can have a real understanding of what can and cannot be achieved by current science. The development of understanding of the human genome makes the need for clearer legislation in this are more urgent.

  16. Preconception Carrier Screening

    MedlinePlus

    ... What can the results of a carrier screening test tell me? A genetic counselor or your health care provider will use the results to calculate the ... the publisher. Related FAQs Genetic Disorders (FAQ094) Screening Tests for Birth Defects ... Education & Events Annual Meeting CME Overview CREOG ...

  17. Behavioral Screening for Toxicology

    EPA Science Inventory

    Screening for behavioral toxicity, or neurotoxicity, has been in use for decades; however, only in the past 20 years has this become a standard practice in toxicology. Current screening batteries, such as the functional observational battery (FOB), are derived from protocols use...

  18. Ocular Screening System

    NASA Technical Reports Server (NTRS)

    1985-01-01

    An ocular screening system designed for safe, convenient screening of large groups was developed at Marshall Space Flight Center, leading to the formation of Medical Sciences Corporation. The system identifies visual defects accurately and inexpensively, and includes a photorefractor telephoto lens and an electronic flash. Medical Sciences Corporation is using the device to test at schools, industrial plants, etc.

  19. Tailoring Magnetism in Quantum Dots

    NASA Astrophysics Data System (ADS)

    Zutic, Igor; Abolfath, Ramin; Hawrylak, Pawel

    2007-03-01

    We study magnetism in magnetically doped quantum dots as a function of particle numbers, temperature, confining potential, and the strength of Coulomb interaction screening. We show that magnetism can be tailored by controlling the electron-electron Coulomb interaction, even without changing the number of particles. The interplay of strong Coulomb interactions and quantum confinement leads to enhanced inhomogeneous magnetization which persists at substantially higher temperatures than in the non-interacting case or in the bulk-like dilute magnetic semiconductors. We predict a series of electronic spin transitions which arise from the competition between the many-body gap and magnetic thermal fluctuations. Cond-mat/0612489. [1] R. Abolfath, P. Hawrylak, I. Zuti'c, preprint.

  20. Electric current and magnetic field effects on bacterial biofilms

    NASA Astrophysics Data System (ADS)

    Sandvik, Elizabeth Louise

    The ability of bacteria to form and grow as biofilm presents a major challenge in clinical medicine. Through this work, two alternative electromagnetic treatment strategies were investigated to combat bacterial biofilms like those that cause chronic infections on indwelling medical devices. Direct electric current (DC) was applied at current densities of 0.7 to 1.8 mA/cm2 alone and in conjunction with antibiotic. Unlike most previous studies, chloride ions were included in the treatment solution at a physiologically-relevant concentration. Using this approach, low levels of DC alone were demonstrated to have a dose-responsive, biocidal effect against Staphylococcus epidermidis and Pseudomonas aeruginosa biofilms with no synergistic enhancement of antibiotic activity. Through a series of experiments using chemical measures, cell viability, and global gene expression, electrolytic generation of chlorine, a potent disinfectant, was identified as the predominant mechanism by which DC kills bacteria in biofilm. The second treatment strategy investigated weak, extremely low-frequency magnetic fields (ELF-MFs) as a noninvasive approach, involving an extension of concepts from well-studied ELF-MF effects observed in eukaryotic systems to bacterial biofilm. S. epidermidis biofilms grown in weak, extremely low-frequency magnetic fields (ELF-MFs) at Ca2+ and K+ ion resonance frequencies were assessed using global gene expression to determine if S. epidermidis in biofilm detect and respond to ELF-MFs. Frequency-dependent changes in gene expression were observed with upregulation of genes involved in transposase activity, signal transduction systems, and membrane transport processes indicating possible effects consistent with theories of ELF-MF induced changes in ion transport reported in eukaryotic cells. This is the first transcriptome study to indentify ELF-MF effects in bacteria. While no direct biocidal effect was observed with ELF-MF treatment, alteration of membrane

  1. Specialty magnets

    SciTech Connect

    Halbach, K.

    1986-07-01

    A number of basic conceptual designs are explained for magnet systems that use permanent magnet materials. Included are iron free multipoles and hybrid magnets. Also appended is a discussion of the manufacturing process and magnetic properties of some permanent magnet materials. (LEW)

  2. Psychological screening program overview.

    PubMed

    Wright, Kathleen M; Huffman, Ann H; Adler, Amy B; Castro, Carl A

    2002-10-01

    This article reviews the literature on health surveillance conducted during military deployments, focusing on models for assessing the impact of operational deployments on peacekeepers. A discussion of the stressors and potential mental health consequences of peacekeeping operations follows with relevant examples of findings from U.S. and international military forces. Psychological screening in different peacekeeping operations conducted in U.S. Army-Europe is reviewed. The review begins with the redeployment screening of military personnel deployed to Bosnia mandated under the Joint Medical Surveillance Program, and continues through the present screening of units deployed to Kosovo. The detailed description of the screening program includes a discussion of procedures and measures and demonstrates the evolution of the program. A summary of key findings from the screening program and a discussion of future research directions are provided.

  3. Leuconostoc bacteriophages from blue cheese manufacture: long-term survival, resistance to thermal treatments, high pressure homogenization and chemical biocides of industrial application.

    PubMed

    Pujato, Silvina A; Guglielmotti, Daniela M; Ackermann, Hans-W; Patrignani, Francesca; Lanciotti, Rosalba; Reinheimer, Jorge A; Quiberoni, Andrea

    2014-05-02

    Nine Leuconostoc mesenteroides phages were isolated during blue cheese manufacture yielding faulty products with reduced eye formation. Their morphologies, restriction profiles, host ranges and long-term survival rates (25°C, 8°C, -20°C and -80°C) were analysed. Based on restriction analysis, six of them were further examined regarding resistance to physical (heat and high pressure homogenization, HPH) and chemical treatments (ethanol, sodium hypochlorite, peracetic acid, biocides A, C, E and F). According to their morphology, L. mesenteroides phages studied in the present work belonged to the Caudovirales order and Siphoviridae family. Six distinct restriction patterns were obtained with EcoRV, HindIII, ClaI and XhoI enzymes, revealing interesting phage diversity in the dairy environment. No significant reductions in phage counts were observed after ten months of storage at -20°C and -80°C, while slightly and moderate decrease in phage numbers were noticed at 8°C and 25°C, respectively. The phages subjected to heat treatments generally showed high resistance at 63°C and moderate resistance at 72°C. However, 80°C for 30 min and 90°C for 2 min led to complete inactivation of viral particles. In general, the best ethanol concentration tested was 75%, as complete inactivation for most Leuconostoc phages within 30 min of incubation was achieved. Peracetic acid, and biocides A, C, E and F were highly effective when used at the same or at a moderately lower concentration as recommended by the producer. Usually, moderate or high concentrations (600-1,600 ppm) of sodium hypochlorite were necessary to completely inactivate phage particles. Leuconostoc phages were partially inactivated by HPH treatments as remaining viral particles were found even after 8 passes at 100 MPa. This is the first report of L. mesenteroides phages isolated from an Argentinean dairy cheese plant. The results of this work could be useful for establishing the most effective physical and

  4. Design and development of a new generation of UV-visible-light-driven nanosized codoped titanium dioxide photocatalysts and biocides/sporocides, and environmental applications

    NASA Astrophysics Data System (ADS)

    Hamal, Dambar B.

    For solar environmental remediation, a new generation of nanosized (< 10 nm) titanium dioxide photocatalysts codoped with metals and nonmetals, or metals only were prepared by the xero-gel and aero-gel methods. For silver or cobalt-based xero-gel titanium dioxide photocatalysts, photoactivities tests revealed that codoping of titanium dioxide with a metal (1% Ag or 2% Co) and nonmetals (carbon and sulfur) is necessary to achieve high-activities for acetaldehyde degradation under visible light (wavelength > 420 nm). It was concluded that high visible-light-activities for acetaldehyde degradation over codoped titanium dioxide were attributed to an interplay of anatase crystallinity, high-surface area, reduced band-gap (< 3.0 eV), uniform dispersion of doped metal ions, and suppressed recombination rate of photogenerated electronhole pairs. Moreover, the nature and amount of codoped metals play a significant role in visible-light-induced photocatalysis. Metals (Al, Ga, and In) doped/codoped titanium dioxide photocatalysts were prepared by the aero-gel method. The photocatalytic studies showed that activities of metal doped/codoped photocatalysts under UV light (wavelength < 400 nm) were found to be dependent on pollutants. Indium demonstrated beneficial effects in both textural and photocatalytic properties. Gallium and indium codoped titanium dioxide photocatalysts displayed even better performance in the CO oxidation reaction under UV light. Notably, titanium dioxide codoped with Ga, In, and Pt, exhibited unique photoactivities for the CO oxidation under both UV and visible light irradiation, indicating that this system could have promise for the water-gas shift reaction for hydrogen production. Silver-based nanostructured titanium dioxide samples were developed for killing human pathogens (Escherichia coli cells and Bacillus subtilis spores). Biocidal tests revealed that silver, carbon, and sulfur codoped titanium dioxide nanoparticles (< 10 nm) possess very strong

  5. REXPO: A catchment model designed to understand and simulate the loss dynamics of plant protection products and biocides from agricultural and urban areas

    NASA Astrophysics Data System (ADS)

    Wittmer, I. K.; Bader, H.-P.; Scheidegger, R.; Stamm, C.

    2016-02-01

    During rain events, biocides and plant protection products are transported from agricultural fields but also from urban sources to surface waters. Originally designed to be biologically active, these compounds may harm organisms in aquatic ecosystems. Although several models allow either urban or agricultural storm events to be predicted, only few combine these two sources, and none of them include biocide losses from building envelopes. This study therefore aims to develop a model designed to predict water and substance flows from urban and agricultural sources to surface waters. We developed a model based on physical principles for water percolation and substance flow including micro- (also called matrix-) and macropore-flows for the agricultural areas together with a model representing sources, sewer systems and a wastewater treatment plant for urban areas. In a second step, the combined model was applied to a catchment where an extensive field study had been conducted. The modelled and measured discharge and compound results corresponded reasonably well in terms of quantity and dynamics. The total cumulative discharge was only slightly lower than the total measured discharge (factor 0.94). The total modelled losses of the agriculturally used herbicide atrazine were slightly lower (∼25%) than the measured losses when the soil pore water distribution coefficient (describing the partition between soil particles and pore water) (Kd) was kept constant and slightly higher if it was increased with time. The modelled urban losses of diuron from facades were within a factor of three with respect to the measured values. The results highlighted the change in importance of the flow components during a rain event from urban sources during the most intensive rain period towards agricultural ones over a prolonged time period. Applications to two other catchments, one neighbouring and one on another continent showed that the model can be applied using site specific data for

  6. Synthesis, characterization and biocidal activity of new organotin complexes of 2-(3-oxocyclohex-1-enyl)benzoic acid.

    PubMed

    Vieira, Flaviana T; de Lima, Geraldo M; Maia, José R da S; Speziali, Nivaldo L; Ardisson, José D; Rodrigues, Leonardo; Correa, Ary; Romero, Oscar B

    2010-03-01

    The reaction of 1,3-cyclohexadione with 2-aminobenzoic acid has produced the 2-(3-oxocyclohex-1-enyl)benzoic acid (HOBz). Subsequent reactions of the ligand with organotin chlorides led to [Me(2)Sn(OBz)O](2) (1), [Bu(2)Sn(OBz)O](2) (2), [Ph(2)Sn(OBz)O](2) (3), [Me(3)Sn(OBz)] (4), [Bu(3)Sn(OBz)] (5) and [Ph(3)Sn(OBz)] (6). All complexes have been fully characterized. In addition the structure of complexes (2) and (4) have been authenticated by X-ray crystallography. The biological activity of all derivatives has been screened against Cryptococcus neoformans and Candida albicans. In addition we have performed toxicological testes employing human kidney cell. The complexes (3), (5) and (6) displayed the best values of inhibition of the fungus growing, superior to ketoconazole. Compound (5) presented promising results in view of the antifungal and cytotoxicity assays.

  7. Barriers to cancer screening.

    PubMed

    Womeodu, R J; Bailey, J E

    1996-01-01

    Many barriers to cancer screening have been summarized and discussed. Barriers have been documented in all patient populations, but some groups such as ethnic minorities and the elderly face unique barriers. The barriers to cancer screening, are multifactorial, but much of the responsibility for change must lie with health care providers and the health care delivery industry. This is not to free the patient of all responsibility, but some significant barriers are beyond their direct control. Take, for example, socioeconomic status, disease knowledge, and culturally related perceptions and myths about cancer detection and treatment. The health care industry must do a better job identifying and overcoming these barriers. The significant effects of provider counseling and advice must not be underestimated. Patients must first be advised, and then further actions must be taken if they reject the screening advice. Did they refuse adherence to recommendations because they do not view themselves as susceptible, because of overwhelming personal barriers, or because of a fatalistic attitude toward cancer detection and treatment? If that is the case, physicians and health care institutions must attempt to change perceptions, educate, and personalize the message so that patients accept their disease susceptibility [table: see text]. Multiple patient and provider risk factors have been identified that can be used to target patients particularly at high risk for inadequate cancer screening and providers at high risk for performing inadequate screening. Research has clearly demonstrated the effectiveness of interventions to improve tracking of patient and physician compliance with screening recommendations. Further research is needed to show the impact of managed-care penetration and payer status on screening efforts, and incentive schemes need to be tested that reward institutions and third-party payers who develop uniform standards and procedures for cancer screening. The

  8. Magnetic testing

    NASA Technical Reports Server (NTRS)

    Pasley, R. L.; Barton, J. R.

    1973-01-01

    Magnetic techniques are described for the nondestructive evaluation of defects in materials. The physical principles, and the magnetic-particle method are discussed along with magnetic-hysteresis measurements and electric current perturbations.

  9. Preschool vision screening.

    PubMed Central

    Jarvis, S N; Tamhne, R C; Thompson, L; Francis, P M; Anderson, J; Colver, A F

    1991-01-01

    Although a good case for preschool screening for vision defects can be made there is very little evidence that existing programmes are effective in practice. A comparative trial of three different methods of preschool vision screening is described. Some 7000 children initially aged 5 months (younger cohorts) and 30 months (older cohorts) in three matched areas entered the trial during 1987. During 18 months of follow up new visual and ocular defects among these children were ascertained through ophthalmology outpatients and from optician records. Screening at 35 months by an orthoptist based in the community is superior to conventional health visitor surveillance at 30 months and to an agreed programme of primary care screening for squint at 30-36 months as judged by screening sensitivity (100% v 50% v 50%) and the incidence of treated target conditions (17 v 3 v 5 per 1000 person years). A notable feature in the area served by the orthoptist is that 13 children received treatment for straight eyed visual acuity loss from among 1000 children whereas there were no such cases among 2500 in the comparison areas. In the younger cohorts (that is, screening at age 5-9 months) all three programmes showed equally poor results, only one of the eight treated target conditions arising from all 3500 younger children being screen detected. PMID:2025002

  10. Neodymium Magnets.

    ERIC Educational Resources Information Center

    Wida, Sam

    1992-01-01

    Uses extremely strong neodymium magnets to demonstrate several principles of physics including electromagnetic induction, Lenz's Law, domain theory, demagnetization, the Curie point, and magnetic flux lines. (MDH)

  11. A magnetic protein biocompass

    NASA Astrophysics Data System (ADS)

    Qin, Siying; Yin, Hang; Yang, Celi; Dou, Yunfeng; Liu, Zhongmin; Zhang, Peng; Yu, He; Huang, Yulong; Feng, Jing; Hao, Junfeng; Hao, Jia; Deng, Lizong; Yan, Xiyun; Dong, Xiaoli; Zhao, Zhongxian; Jiang, Taijiao; Wang, Hong-Wei; Luo, Shu-Jin; Xie, Can

    2016-02-01

    The notion that animals can detect the Earth’s magnetic field was once ridiculed, but is now well established. Yet the biological nature of such magnetosensing phenomenon remains unknown. Here, we report a putative magnetic receptor (Drosophila CG8198, here named MagR) and a multimeric magnetosensing rod-like protein complex, identified by theoretical postulation and genome-wide screening, and validated with cellular, biochemical, structural and biophysical methods. The magnetosensing complex consists of the identified putative magnetoreceptor and known magnetoreception-related photoreceptor cryptochromes (Cry), has the attributes of both Cry- and iron-based systems, and exhibits spontaneous alignment in magnetic fields, including that of the Earth. Such a protein complex may form the basis of magnetoreception in animals, and may lead to applications across multiple fields.

  12. A magnetic protein biocompass.

    PubMed

    Qin, Siying; Yin, Hang; Yang, Celi; Dou, Yunfeng; Liu, Zhongmin; Zhang, Peng; Yu, He; Huang, Yulong; Feng, Jing; Hao, Junfeng; Hao, Jia; Deng, Lizong; Yan, Xiyun; Dong, Xiaoli; Zhao, Zhongxian; Jiang, Taijiao; Wang, Hong-Wei; Luo, Shu-Jin; Xie, Can

    2016-02-01

    The notion that animals can detect the Earth's magnetic field was once ridiculed, but is now well established. Yet the biological nature of such magnetosensing phenomenon remains unknown. Here, we report a putative magnetic receptor (Drosophila CG8198, here named MagR) and a multimeric magnetosensing rod-like protein complex, identified by theoretical postulation and genome-wide screening, and validated with cellular, biochemical, structural and biophysical methods. The magnetosensing complex consists of the identified putative magnetoreceptor and known magnetoreception-related photoreceptor cryptochromes (Cry), has the attributes of both Cry- and iron-based systems, and exhibits spontaneous alignment in magnetic fields, including that of the Earth. Such a protein complex may form the basis of magnetoreception in animals, and may lead to applications across multiple fields.

  13. A History of Vision Screening.

    ERIC Educational Resources Information Center

    Appelboom, Tina M.

    1985-01-01

    The vision screening program has a long and interesting history involving educators, pediatricians, optometrists, and ophthamologists. This historical review of vision screening in the schools includes a discussion of amblyopia and screening of preschool students. (Author/CB)

  14. Linking International Cancer Screening Efforts

    Cancer.gov

    Drs. Sudha Sivaram and Steve Taplin speak at the International Cancer Screening Network (ICSN) Meeting, which brings together individuals involved in cancer screening research and cancer screening programs from the ICSN’s member countries.

  15. Screening for Pancreatic Cancer.

    PubMed

    Ngamruengphong, Saowanee; Canto, Marcia Irene

    2016-12-01

    Pancreatic cancer (PC) is a highly fatal disease that can only be cured by complete surgical resection. However, most patients with PC have unresectable disease at the time of diagnosis, highlighting the need to detect PC and its precursor lesions earlier in asymptomatic patients. Screening is not cost-effective for population-based screening of PC. Individuals with genetic risk factors for PC based on family history or known PC-associated genetic syndromes, however, can be a potential target for PC screening programs. This article provides an overview of the epidemiology and genetic background of familial PC and discusses diagnostic and management approaches.

  16. Screening for Developmental Disabilities

    PubMed Central

    Foster, Carol; Duran-Flores, Deborah; Dumars, Kenneth W.; Stills, Stanley

    1985-01-01

    Developmental disabilities are responsible for a combination of severe physical, mental, psychological and social deficits. They develop before age 22 years and involve a little more than 1% of the population. Screening for developmental disabilities is the first step in their prevention. Various screening instruments are available for use throughout the developmental years that are designed to detect the wide variety of developmental problems that interfere with a developing person's optimal adaptation to his or her environment. The screening instruments must be inexpensive, reproducible, widely available and cost effective to the child, family and society. PMID:2413633

  17. Transient magnetic field and temperature modeling in large magnet applications

    SciTech Connect

    Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. . Space Systems Div.)

    1989-07-01

    This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.

  18. Monochloramine and chlorine dioxide for controlling Legionella pneumophila contamination: biocide levels and disinfection by-product formation in hospital water networks.

    PubMed

    Marchesi, Isabella; Ferranti, Greta; Bargellini, Annalisa; Marchegiano, Patrizia; Predieri, Guerrino; Stout, Janet E; Borella, Paola

    2013-12-01

    Legionella colonization in hospital hot water distribution networks was evaluated following 36 months of continuous treatment with monochloramine and compared with chlorine dioxide. Nitrite, nitrate, chlorite, chlorate, bromide, trihalomethanes and haloacetic acids as well as the biocide concentration at sampled points were measured. Only 8/84 samples treated with monochloramine were found contaminated and after the first 8 months of treatment no Legionella was isolated. Chlorine dioxide was associated with a strong reduction in Legionella contamination compared to pre-treatment, but differences according to the device were observed. Monochloramine between 2 and 3 mg l(-1) and chlorine dioxide between 0.50 and 0.70 mg l(-1) were needed to control Legionella colonization. Comparing no- and post-flush samples, a higher frequency of no-flush positive samples was noted using chlorine dioxide, suggesting an increased risk for patients when they open the tap. No increase in chlorite levels and no water nitrification occurred by using monochloramine. Chlorite at levels exceeding the limit requested for drinking water was measured when chlorine dioxide was applied. In conclusion, we highlight that continuous injection of monochloramine should be considered as an effective alternative to chlorine dioxide in controlling legionellae contamination inside hospital water distribution systems.

  19. Biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid/hyperbranched epoxy nanocomposites: Mechanical, thermal, antimicrobial and optical properties.

    PubMed

    De, Bibekananda; Gupta, Kuldeep; Mandal, Manabendra; Karak, Niranjan

    2015-11-01

    The present work demonstrated a transparent thermosetting nanocomposite with antimicrobial and photoluminescence attributes. The nanocomposites are fabricated by incorporation of different wt.% (1, 2 and 3) of a biocide immobilized OMMT-carbon dot reduced Cu2O nanohybrid (MITH-NH) in the hyperbranched epoxy matrix. MITH-NH is obtained by immobilization of 2-methyl-4-isothiazolin-3-one hydrochloride (MITH) at room temperature using sonication on OMMT-carbon dot reduced Cu2O nanohybid. The nanohybrid is prepared by reduction of cupric acetate using carbon dot as the reducing agent in the presence of OMMT at 70°C. The significant improvements in tensile strength (~2 fold), elongation at break (3 fold), toughness (4 fold) and initial thermal degradation temperature (30°C) of the pristine hyperbranched epoxy system are achieved by incorporation of 3wt.% of MITH-NH in it. The nanocomposites exhibit strong antimicrobial activity against Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas aeruginosa bacteria and Candida albicans, a fungus. The nanocomposite also shows significant activity against biofilm formation compared to the pristine thermoset. Further, the nanocomposite films emit different colors on exposure of different wavelengths of UV light. The properties of these nanocomposites are also compared with the same nanohybrid without OMMT.

  20. Colonisation and succession of marine biofilm-dwelling ciliate assemblages on biocidal antifouling and fouling-release coatings in temperate Australia.

    PubMed

    Watson, Matthew G; Scardino, Andrew J; Zalizniak, Liliana; Shimeta, Jeff

    2015-01-01

    Ciliate assemblages are often overlooked, but ubiquitous components of microbial biofilms which require a better understanding. Ciliate, diatom and bacterial colonisation were evaluated on two fouling-release (FR) coatings, viz. Intersleek 970 and Hempasil X3, and two biocidal antifouling (AF) coatings, viz. Intersmooth 360 and Interspeed 5640, in Port Phillip Bay, Australia. A total of 15 genera were identified during the 10 week deployment. Intersleek 970 displayed the most rapid fouling by ciliates, reaching 63.3(± 5.9) cells cm(-2). After 10 weeks, all four coatings were extensively fouled. However, the toxicity of the AF coatings still significantly inhibited microbial fouling compared to the FR coatings. On all treatments, colonies of sessile peritrichs dominated the ciliate assemblage in the early stage of succession, but as the biofilm matured, vagile ciliates exerted more influence on the assemblage structure. The AF coatings showed selective toxic effects, causing significant differences in the ciliate species assemblages among the treatments.

  1. Effect of the shell-forming polymer ratio on the encapsulation of tea tree oil by complex coacervation as a natural biocide.

    PubMed

    Pérez-Limiñana, María Ángeles; Payá-Nohales, Federico J; Arán-Ais, Francisca; Orgilés-Barceló, César

    2014-01-01

    The aim of this study was to develop footwear materials with antimicrobial properties using microencapsulated Tea Tree oil (TTO) as a natural biocide. For that purpose, gelatine-carboxymethylcellulose based microcapsules containing TTO were synthesised by a complex coacervation process. Furthermore, the influence of the gelatine (G)/sodium carboxymethylmethyl cellulose (CMC) ratio (G/C) on the microcapsule properties, as well as in the microencapsulation oil efficiency, was evaluated. The microcapsules were characterised by different experimental techniques and applied to footwear materials (leather and textile) to evaluate their performance. The microcapsule durability under different conditions, such as rubbing and ironing, was analysed in order to simulate shoe manufacturing and shoe wearing. The properties of the microcapsules obtained by complex coacervation, using gelatine and sodium carboxymethylcellulose as shell-forming polymers, are determined by the ratio between those two polymers (G/C). The results obtained showed a notable effect of G/C ratio on the formation of the coacervate during the synthesis process and also on the encapsulation efficiency of the antimicrobial oil, with the optimal value for the G/C ratio being around 10.

  2. Cationic Oligo(thiophene ethynylene) with Broad-Spectrum and High Antibacterial Efficiency under White Light and Specific Biocidal Activity against S. aureus in Dark.

    PubMed

    Zhao, Qi; Li, Junting; Zhang, Xiaoqian; Li, Zhengping; Tang, Yanli

    2016-01-13

    We designed and synthesized a novel oligo(thiophene ethynylene) (OTE) to investigate the antibacterial activities against Gram-positive (Staphylococcus aureus and Staphylococcus epidermidis) and Gram-negative (Ralstonia solanacearum and Escherichia coli) bacteria in vitro by photodynamic therapy (PDT). Notably, OTE presents broad-spectrum and greatly high antibacterial activities after white light irradiation at nanogram per milliliter concentrations. The half inhibitory concentrations (IC50) values obtained for S. aureus, S. epidermidis, E. coli, and R. solanacearum are 8, 13, 24, and 52 ng/mL after illumination for 30 min, respectively, which are lower than that of other PDT agents. Interestingly, OTE shows the specific and very strong dark killing capability against S. aureus at the concentration of 180 ng/mL for 30 min, which is the highest efficiency biocide against S. aureus without the need of irradiation to date. The antibacterial mechanism investigated demonstrated that reactive oxygen species or singlet-oxygen generated by OTE kills bacteria irreversibly upon white light irradiation, and OTE as a v-type oligomer exerts its toxicity directly on destroying bacterial cytoplasmic membrane in the dark. Importantly, the OTE shows no cell cytotoxicity and excellent biocompatibility. The results indicate that it is potential to provide versatile applications in the efficient control of pathogenic organisms and specific application for killing S. aureus.

  3. Telechelic Poly(2-oxazoline)s with a biocidal and a polymerizable terminal as collagenase inhibiting additive for long-term active antimicrobial dental materials

    PubMed Central

    Fik, Christoph P.; Konieczny, Stefan; Pashley, David H.; Waschinski, Christian J.; Ladisch, Reinhild S.; Salz, Ulrich; Bock, Thorsten; Tiller, Joerg C.

    2015-01-01

    Although modern dental repair materials show excellent mechanical and adhesion properties, they still face two major problems: First, any microbes that remain alive below the composite fillings actively decompose dentin and thus, subsequently cause secondary caries. Second, even if those microbes are killed, the extracellular proteases such as MMP, remain active and can still degrade collagenousdental tissue. In order to address both problems, a poly(2-methyloxazoline) with a biocidal quaternary ammonium and a polymerizable methacrylate terminal was explored as additive for a commercial dental adhesive. It could be demonstrated that the adhesive rendered the adhesive contact-active antimicrobial against S. mutans at a concentration of only 2.5 wt% and even constant washing with water for 101 days did not diminish this effect. Increasing the amount of the additive to 5 wt% allowed killing S. mutans cells in the tubuli of bovinedentin upon application of the adhesive. Further, the additive fully inhibited bacterial collagenase at a concentration of 0.5 wt% and reduced human recombinant collagenase MMP-9 to 13% of its original activity at that concentration. Human MMPs naturally bound to dentin were inhibited by more than 96% in a medium containing 5 wt% of the additive. Moreover, no adverse effect on the enamel/dentine shear bond strength was detected in combination with a dental composite. PMID:25130877

  4. Newborn Screening Tests

    MedlinePlus

    ... difference between lifelong impairment and healthy development. Which Tests Are Offered? Newborn screening varies by state and is subject to change, especially given advancements in technology. However, the disorders listed here are those usually ...

  5. Early School Screening Practices

    ERIC Educational Resources Information Center

    Maitland, Suzanne; And Others

    1974-01-01

    To ascertain the prevalence of early school screening practices, the specific tests employed, and the use made of the test results, a survey was conducted of a representative sample of 980 school districts in the United States. (Author)

  6. Prostate Cancer Screening

    MedlinePlus

    ... treat. There is no standard screening test for prostate cancer. Researchers are studying different tests to find those ... PSA level may be high if you have prostate cancer. It can also be high if you have ...

  7. RAS - Screens & Assays

    Cancer.gov

    A primary goal of the RAS Initiative is to develop assays for RAS activity, localization, and signaling and adapt those assays so they can be used for finding new drug candidates. Explore the work leading to highly validated screening protocols.

  8. Environmental Stress Screening 2000

    NASA Technical Reports Server (NTRS)

    Gibbel, Mark

    1997-01-01

    The following identifies the authors of this report and the organizations that sponsored the effort conducted under the National Center for Manufacturing Sciences (NCMS) Environmental Stress Screening (ESS) 2000 Project.

  9. Colorectal cancer screening.

    PubMed

    Bessa Caserras, Xavier

    2016-09-01

    In the latest meeting of the American Gastroenterological Association, several clinical studies were presented that aimed to evaluate the various colorectal cancer screening strategies, although most assessed the various aspects of faecal immunochemical testing (FIT) and colonoscopy. Data were presented from consecutive FIT-based screening rounds, confirming the importance of adherence to consecutive screening rounds, achieving a similar or superior diagnostic yield to endoscopic studies. There was confirmation of the importance of not delaying endoscopic study after a positive result. Participants with a negative FIT (score of 0) had a low risk for colorectal cancer. Several studies seemed to confirm the importance of high-quality colonoscopy in colorectal cancer screening programmes. The implementation of high-quality colonoscopies has reduced mortality from proximal lesions and reduced interval cancers in various studies. Finally, participants with a normal colonoscopy result or with a small adenoma are at low risk for developing advanced neoplasms during follow-up.

  10. Screening for Glaucoma

    MedlinePlus

    ... enough evidence to determine the potential benefits and harms of glaucoma screening for adults who do not ... Glaucoma is a group of diseases that can harm the eye’s optic nerve. The optic nerve carries ...

  11. Regional Screening Levels (RSLs)

    EPA Pesticide Factsheets

    Regional Screening Level RSL Home Page introduces risk assessors to Chemical Risk Assessment preliminary remediation goals PRG risk based concentration RBC and risk calculations for the assessment of human Health.

  12. Newborn screening tests

    MedlinePlus

    Newborn screening tests look for developmental, genetic, and metabolic disorders in the newborn baby. This allows steps to be taken before symptoms develop. Most of these illnesses are very rare, but can be treated if caught ...

  13. Urine drug screen

    MedlinePlus

    Drug screen -- urine ... detect the presence of illegal and some prescription drugs in your urine. Their presence indicates that you recently used these drugs. Some drugs may remain in your system for ...

  14. Carotid Artery Screening

    MedlinePlus

    ... plaque and the injury it causes is called atherosclerosis . Over time, the walls of affected arteries thicken ... disease (CAD) obesity physical inactivity family history of atherosclerosis and/or stroke Screening Recommendations Carotid Duplex US ...

  15. Lung Cancer Screening

    MedlinePlus

    ... medical care even if there are symptoms. False-positive test results can occur. Screening test results may ... even though no cancer is present. A false-positive test result (one that shows there is cancer ...

  16. Esophageal Cancer Screening

    MedlinePlus

    ... medical care even if there are symptoms. False-positive test results can occur. Screening test results may ... even though no cancer is present. A false-positive test result (one that shows there is cancer ...

  17. Endometrial Cancer Screening

    MedlinePlus

    ... medical care even if she has symptoms. False-positive test results can occur. Screening test results may ... even though no cancer is present. A false-positive test result (one that shows there is cancer ...

  18. Cervical Cancer Screening

    MedlinePlus

    ... cases of cervical cancer and the number of deaths due to cervical cancer since 1950. Cervical dysplasia ... for cervical cancer helps decrease the number of deaths from the disease. Regular screening of women between ...

  19. Barriers to screening mammography.

    PubMed

    Sarma, Elizabeth A

    2015-01-01

    Breast cancer (BRCA) is the second most commonly diagnosed cancer among women in the USA, and mammography is an effective means for the early detection of BRCA. Identifying the barriers to screening mammography can inform research, policy and practice aiming to increase mammography adherence. A literature review was conducted to determine common barriers to screening mammography adherence. PsycINFO and PubMed databases were searched to identify studies published between 2000 and 2012 that examined barriers associated with reduced mammography adherence. Three thematic groups of barriers, based on social ecology, were identified from the literature: healthcare system-level, social and individual-level barriers. Researchers must consider screening behaviour in context and, therefore, should simultaneously consider each level of barriers when attempting to understand screening behaviour and create interventions to increase mammography adherence.

  20. TB Screening Tests

    MedlinePlus

    ... known as: Purified Protein Derivative; PPD; Mantoux; Latent Tuberculosis Infection Test; Interferon-gamma Release Assays; IGRA; T- ... else I should know? How is it used? Tuberculosis (TB) screening tests are not used as general ...

  1. Screening for Depression

    MedlinePlus

    Depression and Bipolar Support Alliance Crisis Hotline Information Coping with a Crisis Suicide Prevention Information Psychiatric Hospitalization ... sign-up Education info, training, events Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/ ...

  2. Lung cancer screening update

    PubMed Central

    Dhillon, Samjot Singh; Loewen, Gregory; Jayaprakash, Vijayvel; Reid, Mary E.

    2013-01-01

    Lung cancer is the leading cause of cancer-related mortality globally and the American cancer society estimates approximately 226,160 new cases and 160,340 deaths from lung cancer in the USA in the year 2012. The majority of lung cancers are diagnosed in the later stages which impacts the overall survival. The 5-year survival rate for pathological st age IA lung cancer is 73% but drops to only 13% for stage IV. Thus, early detection through screening and prevention are the keys to reduce the global burden of lung cancer. This article discusses the current state of lung cancer screening, including the results of the National Lung Cancer Screening Trial, the consideration of implementing computed tomography screening, and a brief overview of the role of bronchoscopy in early detection and potential biomarkers that may aid in the early diagnosis of lung cancer. PMID:23599684

  3. High-throughput fragment screening by affinity LC-MS.

    PubMed

    Duong-Thi, Minh-Dao; Bergström, Maria; Fex, Tomas; Isaksson, Roland; Ohlson, Sten

    2013-02-01

    Fragment screening, an emerging approach for hit finding in drug discovery, has recently been proven effective by its first approved drug, vemurafenib, for cancer treatment. Techniques such as nuclear magnetic resonance, surface plasmon resonance, and isothemal titration calorimetry, with their own pros and cons, have been employed for screening fragment libraries. As an alternative approach, screening based on high-performance liquid chromatography separation has been developed. In this work, we present weak affinity LC/MS as a method to screen fragments under high-throughput conditions. Affinity-based capillary columns with immobilized thrombin were used to screen a collection of 590 compounds from a fragment library. The collection was divided into 11 mixtures (each containing 35 to 65 fragments) and screened by MS detection. The primary screening was performed in <4 h (corresponding to >3500 fragments per day). Thirty hits were defined, which subsequently entered a secondary screening using an active site-blocked thrombin column for confirmation of specificity. One hit showed selective binding to thrombin with an estimated dissociation constant (K (D)) in the 0.1 mM range. This study shows that affinity LC/MS is characterized by high throughput, ease of operation, and low consumption of target and fragments, and therefore it promises to be a valuable method for fragment screening.

  4. Virtual screening against obesity.

    PubMed

    Markt, P; Herdlinger, S; Schuster, D

    2011-01-01

    The development of novel drugs against obesity is one of the top priorities of worldwide drug research. In recent years, it has been facilitated by the application of virtual screening methods. In this review, we give a short introduction into obesity-related protein targets and computer-aided drug design techniques. Furthermore, we highlight the most successful virtual screening studies, outline their results, and provide suggestions for future anti-obesity drug development.

  5. Delivery of Cancer Screening

    PubMed Central

    Fenton, Joshua J.; Cai, Yong; Weiss, Noel S.; Elmore, Joann G.; Pardee, Roy E.; Reid, Robert J.; Baldwin, Laura-Mae

    2012-01-01

    Background Patients and physicians strongly endorse the importance of preventive or periodic health examinations (PHEs). However, the extent to which PHEs contribute to the delivery of cancer screening is uncertain. Methods In a retrospective cohort study, we determined the association between receipt of a PHE and cancer testing in a population-based sample of enrollees in a Washington State health plan who were aged 52 to 78 years and eligible for colorectal, breast, or prostate cancer screening in 2002–2003 (N = 64 288). Outcomes included completion of any colorectal cancer testing (fecal occult blood testing, sigmoidoscopy, colonoscopy, or barium enema), screening mammography, and prostate-specific antigen testing. Results More than half (52.4%) of the enrollees received a PHE during the study period. After adjusting for demographics, comorbidity, number of outpatient visits, and historical preventive service use before January 1, 2002, receipt of a PHE was significantly associated with completion of colorectal cancer testing (incidence difference, 40.4% [95% confidence interval (CI), 39.4%–41.3%]; relative incidence, 3.47 [95% CI, 3.34–3.59]), screening mammography [incidence difference, 14.2% [95% CI, 12.7%–15.7%]; relative incidence, 1.23 [95% CI, 1.20–1.25]), and prostate-specific antigen testing (incidence difference, 39.4% [95% CI, 38.3%–40.5%]; relative incidence, 3.06 [95% CI, 2.95–3.18]). Conclusions Among managed care enrollees eligible for cancer screening, PHE receipt is associated with completion of colorectal, breast, and prostate cancer testing. In similar populations, the PHE may serve as a clinically important forum for the promotion of evidence-based colorectal cancer and breast cancer screening and of screening with relatively less empirical support, such as prostate cancer screening. PMID:17389289

  6. Aircrew Screening Instruments Review

    DTIC Science & Technology

    2007-09-01

    available tools . Several vendors indicated that they will have new selection instruments available within a few months. These are not listed. As noted...AFCAPS-FR-2011-0012 AIRCREW SCREENING INSTRUMENTS REVIEW Diane L. Damos Damos Aviation Services, Inc...June 2007 – August 2007 4. TITLE AND SUBTITLE Aircrew Screening Instruments Review 5a. CONTRACT NUMBER FA3089-06-F-0385 5b. GRANT NUMBER 5c

  7. Screening of solar cells

    NASA Technical Reports Server (NTRS)

    Appelbaum, J.; Chait, A.; Thompson, D. A.

    1993-01-01

    Because solar cells in a production batch are not identical, screening is performed to obtain similar cells for aggregation into arrays. A common technique for screening is based on a single operating point of the I-V characteristic of the cell, usually the maximum power point. As a result, inferior cell matching may occur at the actual operating points. Screening solar cells based on the entire I-V characteristic will inherently result in more similar cells in the array. An array consisting of more similar cells is likely to have better overall characteristics and more predictable performance. Solar cell screening methods and cell ranking are discussed. The concept of a mean cell is defined as a cell 'best' representing all the cells in the production batch. The screening and ranking of all cells are performed with respect to the mean cell. The comparative results of different screening methods are illustrated on a batch of 50 silicon cells of the Space Station Freedom.

  8. Improved Screened Hydrogenic Model

    SciTech Connect

    Nishikawa, T.

    1996-05-01

    Screened Hydrogenic Model is widely used for energy level calculation in hydrodynamic code of inertial confinement fusion because Screened Hydrogenic Model is simple algebraic calculation. More{close_quote}s Screened Hydrogenic Model and his screening constants are usually used to calculate opacity and equation of state. By the use of his model, energy level can be consistently calculated with ion{close_quote}s total energy. But his model take into account the principal quantum number dependence only and cannot reproduce hydrogenic energy levels. As the precise experiment about opacity measurement is performed, it becomes clear that his model is not enough to use for opacity calculation. In this paper, his model is improved in the framework of Screened Hydrogenic Model. The improved model can reproduce the hydrogenic energy levels and include azimuthal quantum number dependence and the effect from another quantum state (a kind of inner quantum number). Screening constants are fitted by spectroscopic data and sophisticate calculations. By the use of improved model, energy levels are calculated more accurately for low-{ital z} ions. {copyright} {ital 1996 American Institute of Physics.}

  9. Magnetic Levitation.

    ERIC Educational Resources Information Center

    Rossing, Thomas D.; Hull, John R.

    1991-01-01

    Discusses the principles of magnetic levitation presented in the physics classroom and applied to transportation systems. Topics discussed include three classroom demonstrations to illustrate magnetic levitation, the concept of eddy currents, lift and drag forces on a moving magnet, magnetic levitation vehicles, levitation with permanent magnets…

  10. Magnetic Spinner

    ERIC Educational Resources Information Center

    Ouseph, P. J.

    2006-01-01

    A science toy sometimes called the "magnetic spinner" is an interesting class demonstration to illustrate the principles of magnetic levitation. It can also be used to demonstrate Faraday's law and a horizontally suspended physical pendulum. The levitated part contains two circular magnets encased in a plastic housing. Each magnet stays…

  11. Students' Compulsion To Screen: Research on Kenneth Burke's Terministic Screens.

    ERIC Educational Resources Information Center

    Strasma, Kip

    Kenneth Burke suggests that language operates from ultimate motives centered around "god-terms" through terministic screens. God-terms represent the strongest terministic screens in any culture: they screen attention to selected realities while screening or deflecting away others. A model of composition can be constructed from these…

  12. 8. DETAIL OF COMPUTER SCREEN AND CONTROL BOARDS: LEFT SCREEN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    8. DETAIL OF COMPUTER SCREEN AND CONTROL BOARDS: LEFT SCREEN TRACKS RESIDUAL CHLORINE; INDICATES AMOUNT OF SUNLIGHT WHICH ENABLES OPERATOR TO ESTIMATE NEEDED CHLORINE; CENTER SCREEN SHOWS TURNOUT STRUCTURES; RIGHT SCREEN SHOWS INDICATORS OF ALUMINUM SULFATE TANK FARM. - F. E. Weymouth Filtration Plant, 700 North Moreno Avenue, La Verne, Los Angeles County, CA

  13. Magnetic power piston fluid compressor

    NASA Technical Reports Server (NTRS)

    Gasser, Max G. (Inventor)

    1994-01-01

    A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

  14. [Organized breast cancer screening].

    PubMed

    Rouëssé, Jacques; Sancho-Garnier, Hélèn

    2014-02-01

    Breast screening programs are increasingly controversial, especially regarding two points: the number of breast cancer deaths they avoid, and the problem of over-diagnosis and over-treatment. The French national breast cancer screening program was extended to cover the whole country in 2004. Ten years later it is time to examine the risk/benefit ratio of this program and to discuss the need for change. Like all forms of cancer management, screening must be regularly updated, taking into account the state of the art, new evidence, and uncertainties. All screening providers should keep themselves informed of the latest findings. In the French program, women aged 50-74 with no major individual or familial risk factors for breast cancer are offered screening mammography and clinical breast examination every two years. Images considered non suspicious of malignancy by a first reader are re-examined by a second reader. The devices and procedures are subjected to quality controls. Participating radiologists (both public and private) are required to read at least 500 mammographies per year. The program's national participation rate was 52.7 % in 2012. When individual screening outside of the national program is taken into account (nearly 15 % of women), coverage appears close to the European recommendation of 65 %. Breast cancer mortality has been falling in France by 0.6 % per year for over 30 years, starting before mass screening was implemented, and by 1.5 % since 2005. This decline can be attributed in part to earlier diagnosis and better treatment, so that the specific impact of screening cannot easily be measured. Over-treatment, defined as the detection and treatment of low-malignancy tumors that would otherwise not have been detected in a person's lifetime, is a major negative effect of screening, but its frequency is not precisely known (reported to range from 1 % to 30 %). In view of these uncertainties, it would be advisable to modify the program in order to

  15. Physics in Screening Environments

    NASA Astrophysics Data System (ADS)

    Certik, Ondrej

    In the current study, we investigated atoms in screening environments like plasmas. It is common practice to extract physical data, such as temperature and electron densities, from plasma experiments. We present results that address inherent computational difficulties that arise when the screening approach is extended to include the interaction between the atomic electrons. We show that there may arise an ambiguity in the interpretation of physical properties, such as temperature and charge density, from experimental data due to the opposing effects of electron-nucleus screening and electron-electron screening. The focus of the work, however, is on the resolution of inherent computational challenges that appear in the computation of two-particle matrix elements. Those enter already at the Hartree-Fock level. Furthermore, as examples of post Hartree-Fock calculations, we show second-order Green's function results and many body perturbation theory results of second order. A self-contained derivation of all necessary equations has been included. The accuracy of the implementation of the method is established by comparing standard unscreened results for various atoms and molecules against literature for Hartree-Fock as well as Green's function and many body perturbation theory. The main results of the thesis are presented in the chapter called Screened Results, where the behavior of several atomic systems depending on electron-electron and electron-nucleus Debye screening was studied. The computer code that we have developed has been made available for anybody to use. Finally, we present and discuss results obtained for screened interactions. We also examine thoroughly the computational details of the calculations and particular implementations of the method.

  16. Breast Cancer Screening in the Precision Medicine Era: Risk-Based Screening in a Population-Based Trial.

    PubMed

    Shieh, Yiwey; Eklund, Martin; Madlensky, Lisa; Sawyer, Sarah D; Thompson, Carlie K; Stover Fiscalini, Allison; Ziv, Elad; Van't Veer, Laura J; Esserman, Laura J; Tice, Jeffrey A

    2017-01-01

    Ongoing controversy over the optimal approach to breast cancer screening has led to discordant professional society recommendations, particularly in women age 40 to 49 years. One potential solution is risk-based screening, where decisions around the starting age, stopping age, frequency, and modality of screening are based on individual risk to maximize the early detection of aggressive cancers and minimize the harms of screening through optimal resource utilization. We present a novel approach to risk-based screening that integrates clinical risk factors, breast density, a polygenic risk score representing the cumulative effects of genetic variants, and sequencing for moderate- and high-penetrance germline mutations. We demonstrate how thresholds of absolute risk estimates generated by our prediction tools can be used to stratify women into different screening strategies (biennial mammography, annual mammography, annual mammography with adjunctive magnetic resonance imaging, defer screening at this time) while informing the starting age of screening for women age 40 to 49 years. Our risk thresholds and corresponding screening strategies are based on current evidence but need to be tested in clinical trials. The Women Informed to Screen Depending On Measures of risk (WISDOM) Study, a pragmatic, preference-tolerant randomized controlled trial of annual vs personalized screening, will study our proposed approach. WISDOM will evaluate the efficacy, safety, and acceptability of risk-based screening beginning in the fall of 2016. The adaptive design of this trial allows continued refinement of our risk thresholds as the trial progresses, and we discuss areas where we anticipate emerging evidence will impact our approach.

  17. Newborn screening in India.

    PubMed

    Rama Devi, A Radha; Naushad, S M

    2004-02-01

    Expanded newborn screening (NBS) is aimed for early detection and intervention of treatable inborn errors of metabolism and also to establish incidence of these disorders in this part of the globe. The first expanded NBS programme initiated in the capital city of Andhra Pradesh to screen all the newborns born in four major Government Maternity Hospitals in Hyderabad by heel prick capillary blood collected on S&S 903 filter paper. Chromatographic (TLC and HPLC), electrophoretic (cellulose acetate and agarose) and ELISA based assays have been employed for screening of common inborn errors of metabolism. This study has shown a high prevalence of treatable Inborn errors of metabolism. Congenital hypothyroidsm is the most common disorder (1 in 1700) followed by congenital Adrenal Hyperplasia (1 in 2575) and Hyperhomocystenemia (1 in 100). Interestingly, a very high prevalence of inborn errors of metabolism to the extent of 1 in every thousand newborns was observed. The study reveals the importance of screening in India, necessitating nation wide large-scale screening.

  18. Modelling Faraday Screens in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Wolleben, M.; Reich, W.

    2004-02-01

    Maps of Galactic polarized continuum emission at 1408, 1660, and 1713 MHz towards the local Taurus molecular cloud complex were made with the Effelsberg 100-m telescope. Minima in the polarized emission which are located at the boundary of a molecular cloud were detected. Beside high rotation measures and unusual spectral indices of the polarized intensity, these features are associated with the molecular gas. At the higher frequencies the minima get less distinct. We have modelled the multi-frequency observations by placing magneto-ionic Faraday screens at the distance of the molecular cloud. In this model Faraday rotated background emission adds to foreground emission towards these screens. The systematic variation of the observed properties is the result of different line-of-sight lengths through the screen assuming spherical symmetry. For a distance of 140 pc to the Taurus clouds the physical sizes of the Faraday screens are of the order of 2 pc. In this paper we describe the data calibration and modelling process for one such object. We find an intrinsic rotation measure of about -29 rad m-2 to model the observations. It is pointed out that the observed rotation measure differs from the physical. Further observational constraints from Hα observations limit the thermal electron density to less than 0.8 cm-3, and we conclude that the regular magnetic field strength parallel to the line-of-sight exceeds 20 μG to account for the intrinsic rotation measure.

  19. [Colorectal cancer screening].

    PubMed

    Castells, Antoni

    2013-10-01

    Colorectal cancer is the paradigm of tumoral growth that is susceptible to preventive measures, especially screening. Various screening strategies with demonstrated efficacy and efficiency are currently available, notable examples being the fecal occult blood test and endoscopic tests. In addition, new modalities have appeared in the last few years that could become viable alternatives in the near future. The present article reviews the most important presentations on colorectal screening at the annual congress of the American Gastroenterological Association held in Orlando in May 2013, with special emphasis on the medium- and long-term results of strategies using the fecal occult blood test and flexible sigmoidoscopy, as well as initial experiences with the use of new biomarkers.

  20. Magnetic classification of meteorites

    NASA Astrophysics Data System (ADS)

    Rochette, P.; Sagnotti, L.; Consolmagno, G.; Denise, M.; Folco, L.; Gattacceca, J.; Osete, M.; Pesonen, L.

    2003-04-01

    Magnetic susceptibility (X) provides a versatile rapid and non destructive way to quantify the amount of magnetic minerals (FeNi metal, magnetic oxides and sulfides) on large volume of material. As petrological studies of meteorites suggest that this parameter should be quite discriminant, we assembled a database of measurements on about 1200 stony meteorites from various European collections: Helsinki, Madrid, Moscou, Paris, Prague, Roma, Siena, Vatican, and other smaller collections. From 1 to >20 pieces and 1 to >100 cc per meteorite allow to define a representative mean value, using a large coil (8 cm) Kappabridge. For ordinary chondrites, it appears that weathering is responsible for a systematic bias toward low X for Antarctic (Frontier Mountain) and non Antarctic (mainly from Sahara) finds. Once only falls are considered a quite narrow range of X is observed for a given class, with no effect of petrological grade except for LL. This does not support suggested decrease of metal amount with metamorphism for L chondrites. High grade LLs (heated above 400°C) develop the weakly magnetic antitaenite-tetrataenite phases during slow cooling, explaining the difference with low grade taenite-bearing LLs. Once a few % of outliers are excluded, well defined means for H and L are observed with no overlap at 2 s.d.; this agrees with the lack of overlap on metal amount. For non ordinary chondrites and achondrites, weakly magnetic classes are HED, Aubrites and SNC (below LL), strongly ones are E (above H) and Ureilites (in the L-H range), while C chondrites are spread in the whole range, again with each class showing restricted variation. Outliers appeared to be in most cases either misclassified meteorites or misindentified samples, based on petrographic and microprobe investigations of thin sections from outlying samples. It appears that systematic magnetic screening of large collections is an efficient way to detect erroneous sample identification, due to exchange with

  1. Cytotoxicity and molecular effects of biocidal disinfectants (quaternary ammonia, glutaraldehyde, poly(hexamethylene biguanide) hydrochloride PHMB) and their mixtures in vitro and in zebrafish eleuthero-embryos.

    PubMed

    Christen, Verena; Faltermann, Susanne; Brun, Nadja Rebecca; Kunz, Petra Y; Fent, Karl

    2017-02-21

    Frequently used biocidal disinfectants, including quaternary ammonium compounds (QAC), glutaraldehyde and poly(hexamethylene biguanide) hydrochloride (PHMB), occur in the aquatic environment but their potential effects in fish are poorly known, in particular when occurring as mixtures. To investigate their joint activity, we assessed the cytotoxicity of three QACs (BAC, barquat and benzalkonium chloride), glutaraldehyde andPHMB by the MTT assay individually, followed by assessing binary and ternary mixtures in zebrafish liver cells (ZFL) and human liver cells (Huh7). We also analysed molecular effects by quantitative PCR in vitro and in zebrafish eleuthero-embryos employing a targeted gene expression approach. QACs displayed strong cytotoxicity in both cell lines with EC50 values in the low μg/ml range, while glutaraldehyde and PHMB were less cytotoxic. Most of the binary and both ternary mixtures showed synergistic activity at all equi-effective concentrations. A mixture containing all five compounds mixed at their no observed effect concentrations showed strong cytotoxicity, suggesting a synergistic interaction. Additionally, we determined transcriptional alterations of target genes related to endoplasmatic reticulum (ER) stress, general stress, inflammatory action and apoptosis. Induction of ER stress genes occurred at non-cytotoxic concentrations of barquat, glutaraldehyde and BAC in ZFL cells. Barquat and BAC induced tumor necrosis factor alpha (tnf-α). Similar transcriptional alterations were found in vivo upon exposure of zebrafish eleuthero-embryos for 120h. Glutaraldehyde led to induction of ER stress genes and tnf-α, while BAC additionally induced genes indicative of apoptosis, which was also the case with benzalkonium chloride at the highest concentration. We demonstrated strong cytotoxicity of QACs, and synergistic activity of binary, ternary and quintuple mixtures. Barquat and BAC let to induction of ER stress and inflammation in vitro, and BAC and

  2. Biocidal and Sporicidal Efficacy of Pathoster® 0.35% and Pathoster® 0.50% Against Bacterial Agents in Potential Bioterrorism Use

    PubMed Central

    Candeliere, Antonio; Donatiello, Adelia; Pagano, Stefania; Iatarola, Michela; Tolve, Francesco; Antonino, Leonardo; Fasanella, Antonio

    2016-01-01

    The use of products that can neutralize or significantly reduce the microbial load and that are not harmful to human health and the environment represents a milestone in the fight against the spread of infectious diseases. Peracetic acid, besides being an excellent sterilizing and sporicidal agent, is harmless to humans and the environment when it is used in a common dosage. However, the high costs and loss of efficacy of the product very quickly after its reconstitution limit its use. We evaluated the efficacy and stability of 2 commercial products, based on stabilized peracetic acid (Pathoster® 0.35% and Pathoster® 0.50%) used against spores of Bacillus anthracis and spores of Bacillus cereus and vegetative forms of Yersinia pestis, Burkholderia mallei, Burkholderia pseudomallei, Francisella tularensis, Brucella abortus, and Brucella melitensis. The efficacy tests were based on the direct contact of the products with a standard suspension of the bacteria. The stability of the products was defined as the period of time during which the biocidal and sporicidal properties remained unchanged. The limit of effectiveness was the period after which the product was unable to exert a complete sterilization after a contact of 5 minutes with at least 1 of the 8 bacteria used in this work. Both formulations showed good efficacy against the microorganisms used in the study, confirming the utility of peracetic acid as a sterilizing product. After the reconstitution, Pathoster® 0.35% was stable until 16±1 days, while Pathoster® 0.50% was stable until 24±1 days. The formulations used in this study showed good performance and a significant stability of peracetic acid. PMID:27482880

  3. [Examination of biocides for their effectiveness against animal viruses according to European Union Standards with emphasis on the selection of a suitable test virus].

    PubMed

    Al-Khleif, Ahmad; Baljer, Georg; Herbst, Werner

    2009-01-01

    Because of the changes to be expected in the methods for testing disinfectants deemed to be used in the veterinary field, candidate viral species were evaluated for their suitability as test virus. Considered viral species included different non-enveloped viruses [bovine enterovirus type 1 (ECBO (Enteric Cytopathogenic Bovine Orphan) virus), mammalian reovirus type 1, feline calici virus (FCV), and bovine parvovirus (BPV)], as well as enveloped viruses, as equine arteritisvirus (EAV), bovine herpesvirus type 1 (BHV1), Newcastle disease virus (NDV) and vaccinia virus. Viruses were tested for their tenacity against different biocidal agents (formaldehyde, formic acid, peracetic acid, and sodium hypochlorite) in the suspension test at a temperature of 20 degrees C which is given as an optional test temperature according to prEN 14675 "Quantitative suspension test for the evaluation of virucidal activity of chemical disinfectants and antiseptics used in veterinary field--Test method and requirements"elaborated by the "Comite Européen de Normalisation"(CEN) (Anonym, 2004). Of the animal viruses tested for their tenacity highest tenacity against the disinfectants. FCV and the enveloped viruses were of lower resistance. In addition to the tenacity of viruses, other parameters, such as the ability of the virus to replicate in permanent cells, the magnitude of the virus titre that can be obtained from such cultures, as well as the threat a virus poses to humans and animals are to be considered when selecting a suitable test virus. Based on these criteria and despite its tenacity being inferior to that of BPV, the ECBO virus was chosen as the most suitable test virus. The result of the efficacy of disinfectants is not based on the most resistant virus in this case. This circumstance is to be considered when giving recommendations for the practical use of disinfectants.

  4. Colorectal cancer screening in an expanding panorama of screening programmes.

    PubMed

    Hoff, Geir

    2010-08-01

    Cervical and breast cancer screening programmes have been introduced in times when both the professional requirements for evidence based medicine and public demand for quantification of benefits may have been less explicit. The World Health Organisation has recommended cancer screening only for cervix, breast and colorectal cancer (CRC) - the latter leaving health authorities with a choice between a multitude of screening methods of which the efficacy has been proven only for fecal occult blood testing (FOBT). Although we are far from seeing the perfect screening method and screening programme, cost effectiveness for CRC screening has been estimated at least as cost-effective as established programmes for cervix and breast cancer screening. Established and imminent screening programmes should be considered as natural platforms for randomised trial with commitment and responsibility to continuously improve the quality and effectiveness of the screening service provided.

  5. Neonatal screening: ethical aspects.

    PubMed

    Hermerén, G

    1999-12-01

    The purpose of this paper is to give an overview of the ethical issues raised by neonatal screening for cystic fibrosis and to propose a structure for the ethical analysis of these issues. The structure is based on an analysis of some of the most common shortcomings of ethical analyses. The structure needs to be supplemented by facts about the present state of the art concerning effects and costs of the various screening and treatment alternatives. Such information is provided by other contributions to these proceedings.

  6. Ball valve safety screen

    SciTech Connect

    Bolding, B.H.

    1981-09-01

    A device for preventing unwanted objects from entering the ball assembly of a float collar or float shoe and otherwise damaging or plugging the valve mechanism therein is disclosed. The device comprises a screen constructed of expanded metal and rigidly affixed to the interior of the float collar or float shoe above the ball valve assembly. The screen portion is either mounted to the interior surface of the float collar sleeve by an annular structural member or mounted to a structural band which is partially embedded in the concrete portion of the float collar or casing guide shoe.

  7. Lunar Dust Mitigation Screens

    NASA Astrophysics Data System (ADS)

    Knutson, Shawn; Holloway, Nancy

    With plans for the United States to return to the moon, and establish a sustainable human presence on the lunar surface many issues must be successfully overcome. Lunar dust is one of a number of issues with the potential to create a myriad of problems if not adequately addressed. Samples of dust brought back from Apollo missions show it to be soft, yet sharp and abrasive. The dust consists of a variety of morphologies including spherical, angular blocks, shards, and a number of irregular shapes. One of the main issues with lunar dust is its attraction to stick to anything it comes in contact with (i.e. astronauts, equipment, habitats, etc.). Ionized radiation from the sun strikes the moon's surface and creates an electrostatic charge on the dust. Further, the dust harbors van der Waals forces making it especially difficult to separate once it sticks to a surface. During the Apollo missions, it was discovered that trying to brush the lunar dust from spacesuits was not effective, and rubbing it caused degradation of the suit material. Further, when entering the lunar module after moonwalks, the astronauts noted that the dust was so prolific inside the cabin that they inhaled and ingested it, causing at least one of them, Harrison "Jack" Schmidt, to report irritation of the throat and lungs. It is speculated that the dust could also harm an astronaut's nervous and cardiovascular systems, especially during an extended stay. In addition to health issues, the dust can also cause problems by scouring reflective coatings off of thermal blankets, and roughening surfaces of windows and optics. Further, panels on solar cells and photovoltaics can also be compromised due to dust sticking on the surfaces. Lunar dust has the capacity to penetrate seals, interfere with connectors, as well as mechanisms on digging machines, all of which can lead to problems and failure. To address lunar dust issues, development of electrostatic screens to mitigate dust on sur-faces is currently

  8. Approaches to virtual screening and screening library selection.

    PubMed

    Wildman, Scott A

    2013-01-01

    The ease of access to virtual screening (VS) software in recent years has resulted in a large increase in literature reports. Over 300 publications in the last year report the use of virtual screening techniques to identify new chemical matter or present the development of new virtual screening techniques. The increased use is accompanied by a corresponding increase in misuse and misinterpretation of virtual screening results. This review aims to identify many of the common difficulties associated with virtual screening and allow researchers to better assess the reliability of their virtual screening effort.

  9. Faraday screens associated with local molecular clouds

    NASA Astrophysics Data System (ADS)

    Wolleben, M.; Reich, W.

    2004-11-01

    Polarization observations at λ 21 cm and λ 18 cm towards the local Taurus molecular cloud complex were made with the Effelsberg 100-m telescope. Highly structured, frequency-dependent polarized emission features were detected. We discuss polarization minima with excessive rotation m easures located at the boundaries of molecular clouds. These minima get less pronounced at the higher frequencies. The multi-frequency polarization data have been successfully modeled by considering magneto-ionic Faraday screens at the surface of the molecular clouds. Faraday rotated background emiss ion adds to foreground emission towards these screens in a different way than in its surroundings. The physical size of the Faraday screens is of the order of 2 pc for 140 pc distance to the Taurus clouds. Intrinsic rotation measures between about -18 rad m-2 to -30 rad m-2 are required to model the observations. Depolarization of the background emission is quite small (compatible with zero), indicating a regular magnetic field structure with little turbulence within the Faraday screens. With observational {constraints} for the thermal electron density from Hα observations of less than 0.8 cm-3 we conclude that the regular magnetic field strength along the line of sight exceeds 20 μ G, to account for the observed rotation measure. We discuss some possibilities for the origin of such strong and well ordered magnetic fields. The modeling also predicts a large-scale, regularly polarized emission in the foreground of the Taurus clouds which is of the order of 0.18 K at λ 21 cm. This in turn constrains the observed synchrotron emission in total intensity within 140 pc of the Taurus clouds. A lower limit of about 0.24 K, or about 1.7 K/kpc, is required for a perfectly ordered magnetic field with intrinsic (˜ 75%) percentage polarization. Since this is rather unlikely to be the case, the fraction of foreground synchrotron emission is even larger. This amount of synchrotron emission is

  10. Methane Screening in JET Reverse Field Experiments

    SciTech Connect

    J.D. Strachan; B. Alper; G. Corrigan; S.K. Erents; C. Giroud; A. Korotkov; H. Leggate; G.F. Mathews; R.A. Pitts; M. Stamp; J. Spence

    2004-05-17

    JET plasmas with reverse magnetic field feature a different SOL flow than those with normal field. The observed carbon fueling efficiency from injecting methane gas was similar in reverse and normal field. EDGE2D modeling used an externally applied force to create the SOL flows, without specifying the origin of the force. The resulting flow agreed reasonably with the experimental values between the separatrix and 4 cm mid-plane depth in the SOL. The effect of the flow on the calculated carbon screening was 5 to 15% higher carbon fueling efficiency for the low flow velocity with reverse field.

  11. Planetary magnetism

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1981-01-01

    A synoptic view of early and recent data on the planetary magnetism of Mercury, Venus, the moon, Mars, Jupiter, and Saturn is presented. The data on Mercury from Mariner 10 are synthesized with various other sources, while data for Venus obtained from 120 orbits of Pioneer Venus give the upper limit of the magnetic dipole. Explorer 35 Lunar Orbiter data provided the first evidence of lunar magnetization, but it was the Apollo subsatellite data that measured accurately the magnetic dipole of the moon. A complete magnetic survey of Mars is still needed, and only some preliminary data are given on the magnetic dipole of the planet. Figures on the magnetic dipoles of Jupiter and Saturn are also suggested. It is concluded that if the magnetic field data are to be used to infer the interior properties of the planets, good measures of the multiple harmonics in the field are needed, which may be obtained only through low altitude polar orbits.

  12. 21-Day Content Screen

    EPA Pesticide Factsheets

    Under PRIA, EPA has 21 days after it receives the pesticide application and the fee to conduct an initial screen of the application’s contents for completeness and for the applicant to make necessary corrections. This page provides the checklists we use.

  13. Early Dementia Screening.

    PubMed

    Panegyres, Peter K; Berry, Renee; Burchell, Jennifer

    2016-01-21

    As the population of the world increases, there will be larger numbers of people with dementia and an emerging need for prompt diagnosis and treatment. Early dementia screening is the process by which a patient who might be in the prodromal phases of a dementing illness is determined as having, or not having, the hallmarks of a neurodegenerative condition. The concepts of mild cognitive impairment, or mild neurocognitive disorder, are useful in analyzing the patient in the prodromal phase of a dementing disease; however, the transformation to dementia may be as low as 10% per annum. The search for early dementia requires a comprehensive clinical evaluation, cognitive assessment, determination of functional status, corroborative history and imaging (including MRI, FDG-PET and maybe amyloid PET), cerebrospinal fluid (CSF) examination assaying Aβ1-42, T-τ and P-τ might also be helpful. Primary care physicians are fundamental in the screening process and are vital in initiating specialist investigation and treatment. Early dementia screening is especially important in an age where there is a search for disease modifying therapies, where there is mounting evidence that treatment, if given early, might influence the natural history-hence the need for cost-effective screening measures for early dementia.

  14. Screens and Displays.

    ERIC Educational Resources Information Center

    Edstrom, Malin

    1987-01-01

    Discusses the characteristics of different computer screen technologies including the possible harmful effects on health of cathode ray tube (CRT) terminals. CRT's are compared to other technologies including liquid crystal displays, plasma displays, electroluminiscence displays, and light emitting diodes. A chart comparing the different…

  15. Early Dementia Screening

    PubMed Central

    Panegyres, Peter K.; Berry, Renee; Burchell, Jennifer

    2016-01-01

    As the population of the world increases, there will be larger numbers of people with dementia and an emerging need for prompt diagnosis and treatment. Early dementia screening is the process by which a patient who might be in the prodromal phases of a dementing illness is determined as having, or not having, the hallmarks of a neurodegenerative condition. The concepts of mild cognitive impairment, or mild neurocognitive disorder, are useful in analyzing the patient in the prodromal phase of a dementing disease; however, the transformation to dementia may be as low as 10% per annum. The search for early dementia requires a comprehensive clinical evaluation, cognitive assessment, determination of functional status, corroborative history and imaging (including MRI, FDG-PET and maybe amyloid PET), cerebrospinal fluid (CSF) examination assaying Aβ1–42, T-τ and P-τ might also be helpful. Primary care physicians are fundamental in the screening process and are vital in initiating specialist investigation and treatment. Early dementia screening is especially important in an age where there is a search for disease modifying therapies, where there is mounting evidence that treatment, if given early, might influence the natural history—hence the need for cost-effective screening measures for early dementia. PMID:26838803

  16. Visual Screening: A Procedure.

    ERIC Educational Resources Information Center

    Williams, Robert T.

    Vision is a complex process involving three phases: physical (acuity), physiological (integrative), and psychological (perceptual). Although these phases cannot be considered discrete, they provide the basis for the visual screening procedure used by the Reading Services of Colorado State University and described in this document. Ten tests are…

  17. Screening for fetal aneuploidy.

    PubMed

    Rink, Britton D; Norton, Mary E

    2016-02-01

    Screening is currently recommended in pregnancy for a number of genetic disorders, chromosomal aneuploidy, and structural birth defects in the fetus regardless of maternal age or family history. There is an overwhelming array of sonographic and maternal serum-based options available for carrying out aneuploidy risk assessment in the first and/or second trimester. As with any screening test, the patient should be made aware that a "negative" test or "normal" ultrasound does not guarantee a healthy baby and a "positive" test does not mean the fetus has the condition. The woman should have both pre- and post-test counseling to discuss the benefits, limitations, and options for additional testing. Rapid advancements of genetic technologies have made it possible to screen for the common aneuploidies traditionally associated with advanced maternal age with improved levels of accuracy beyond serum and ultrasound based testing. Prenatal screening for fetal genetic disorders with cell-free DNA has transformed prenatal care with yet unanswered questions related to the financial, ethical, and appropriate application in the provision of prenatal risk assessment.

  18. Competition between Kondo Screening and Quantum Hall Edge Reconstruction

    NASA Astrophysics Data System (ADS)

    Heine, A. W.; Tutuc, D.; Zwicknagl, G.; Haug, R. J.

    2016-03-01

    We report on a Kondo correlated quantum dot connected to two-dimensional leads where we demonstrate the renormalization of the g factor in the pure Zeeman case. i.e., for magnetic fields parallel to the plane of the quantum dot. For the same system, we study the influence of orbital effects by investigating the quantum Hall regime; i.e., a perpendicular magnetic field is applied. In this case an unusual behavior of the suppression of the Kondo effect and of the split zero-bias anomaly is observed. The splitting decreases with magnetic field and shows discontinuous changes that are attributed to the intricate interplay between Kondo screening and the quantum Hall edge structure originating from electrostatic screening. This edge structure, made up of compressible and incompressible stripes, strongly affects the Kondo temperature of the quantum dot and thereby influences the renormalized g factor.

  19. A Complete Analytical Screening Identifies the Real Pesticide Contamination of Surface Waters

    NASA Astrophysics Data System (ADS)

    Moschet, Christoph; Wittmer, Irene; Simovic, Jelena; Junghans, Marion; Singer, Heinz; Stamm, Christian; Leu, Christian; Hollender, Juliane

    2014-05-01

    A comprehensive assessment of pesticides in surface waters is challenging due to the large number of potential contaminants. In Switzerland for example, roughly 500 active ingredients are registered as either plant protection agent (PPA) or as biocide. In addition, an unlimited number of transformations products (TPs) can enter or be formed in surfaced waters. Most scientific publications or regulatory monitoring authorities have implemented 15-40 pesticides in their analytics. Only a few TPs are normally included. Interpretations of the surface water quality based on these subsets remains error prone. In the presented study, we carried out a nearly complete analytical screening covering 86% of all polar organic pesticides (from agricultural and urban sources) in Switzerland (300 substances) and 134 TPs with limits of quantification in the low ng/L range. The comprehensive pesticide screening was conducted by liquid-chromatography coupled to high-resolution tandem mass spectrometry. Five medium-sized rivers (Strahler stream order 3-4, catchment size 35-105 km2), containing high percentiles of diverse crops, orchards and urban settlements in their catchments, were sampled from March till July 2012. Nine subsequent time-proportional bi-weekly composite samples were taken in order to quantify average concentrations. In total, 104 different active ingredients could be detected in at least one of the five rivers. Thereby, 82 substances were only registered as PPA, 20 were registered as PPA and as biocide and 2 were only registered as biocide. Within the PPAs, herbicides had the most frequent detections and the highest concentrations, followed by fungicides and insecticides. Most concentrations were found between 1 and 50 ng/L; however 31 substances (mainly herbicides) had concentrations above 100 ng/L and 3 herbicides above 1000 ng/L. It has to be noted that the measured concentrations are average concentrations over two weeks in medium sized streams and that maximum

  20. PERFORMANCE DEMONSTRATIONS OF ALTERNATIVE SCREEN RECLAMATION PRODUCTS FOR SCREEN PRINTING

    EPA Science Inventory

    This project evaluated environmentally-preferable products for the screen reclamation process In screen printing during month-long demonstrations at 23 printing facilities nationwide. hrough the Environmental Protection Agency (EPA) Design for the Environment Printing Project, pr...