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Sample records for challenged antimicrobial materials

  1. Alternative Antimicrobial Approach: Nano-Antimicrobial Materials

    Directory of Open Access Journals (Sweden)

    Nurit Beyth

    2015-01-01

    Full Text Available Despite numerous existing potent antibiotics and other antimicrobial means, bacterial infections are still a major cause of morbidity and mortality. Moreover, the need to develop additional bactericidal means has significantly increased due to the growing concern regarding multidrug-resistant bacterial strains and biofilm associated infections. Consequently, attention has been especially devoted to new and emerging nanoparticle-based materials in the field of antimicrobial chemotherapy. The present review discusses the activities of nanoparticles as an antimicrobial means, their mode of action, nanoparticle effect on drug-resistant bacteria, and the risks attendant on their use as antibacterial agents. Factors contributing to nanoparticle performance in the clinical setting, their unique properties, and mechanism of action as antibacterial agents are discussed in detail.

  2. Methods of Antimicrobial Coating of Diverse Materials

    Science.gov (United States)

    Akse, James R.; Holtsnider, John T.; Kliestik, Helen

    2011-01-01

    Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

  3. Materials for Space: It's Challenging!

    Science.gov (United States)

    Johnson, Sylvia M.

    2016-01-01

    Space environments place tremendous demands on materials that must perform with exceptional reliability to realize the goals of human or robotic space exploration missions. Materials are subjected to extremes of temperature, pressure, radiation and mechanical loads during all phases of use, including takeoff and ascent, exposure to space or entry into an atmosphere, and operation in a planetary atmosphere. Space materials must be robust and enable the formation of lightweight structures or components that perform the required functions; materials that perform multiple functions are of particular interest. This talk will review the unique challenges for materials in space and some of the specific material capabilities that will be needed for future exploration missions. A description of needs and trends in thermal protection materials and systems will complete the talk.

  4. Antimicrobial and fluoride release capacity of orthodontic bonding materials

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    Erika Machado Caldeira

    2013-07-01

    Full Text Available OBJECTIVE: The aim of this study was to evaluate the antimicrobial and fluoride releasing capacity of 3 bonding materials. MATERIAL AND METHODS: Thirty nine specimens with standardized surface smoothness and dimensions were prepared. The antimicrobial capacity of the materials against S. mutans, L. casei and C. albicans was evaluated by determining the percentage of growth inhibition of these microorganisms in an inoculated medium, obtained by optical density readouts on a spectrophotometer. The potential to interfere in microbial growth on the surface of the studied materials was observed by means of scanning electron microscopy (SEM. The fluoride release capacity in ultrapure water for 14 days was analyzed by means of ion chromatography. RESULTS: The PLUS group presented the highest percentage of microbial inhibition and the most contamination-free surface. The FUJI group presented the best fluoride release capacity. CONCLUSIONS: The TransbondTM Plus Color Change was the one that presented the best general behavior considering the evaluated aspects.

  5. Current and future challenges in the development of antimicrobial agents.

    Science.gov (United States)

    Rennie, Robert P

    2012-01-01

    Micro-organisms exist to survive. Even in the absence of antimicrobial agents, many have determinants of resistance that may be expressed phenotypically, should the need arise. With the advent of the antibiotic age, as more and more drugs were developed to treat serious infections, micro-organisms (particularly bacteria) rapidly developed resistance determinants to prevent their own demise.The most important determinants of resistance have been in the Gram-positive and Gram-negative bacteria. Among Gram-positive bacteria, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE) and penicillin-resistant Streptococcus pneumoniae (PRSP) have taxed researchers and pharmaceutical companies to develop new agents that are effective against these resistant strains. Among the Gram-negative bacteria, extended-spectrum beta-lactamase (ESBL) enzymes, carbapenemases (CREs) and the so-called amp-C enzymes that may be readily transferred between species of enterobacteriaceae and other facultative species have created multi-drug resistant organisms that are difficult to treat. Other resistance determinants have been seen in other clinically important bacterial species such as Neisseria gonorrhoeae, Clostridium difficile, Haemophilus influenzae and Mycobacterium tuberculosis. These issues have now spread to fungal agents of infection.A variety of modalities have been used to stem the tide of resistance. These include the development of niche compounds that target specific resistance determinants. Other approaches have been to find new targets for antimicrobial activity, use of combination agents that are effective against more than one target in the cell, or new delivery mechanism to maximize the concentration of antimicrobial agents at the site of infection without causing toxicity to the host. It is important that such new modalities have been proved effective for clinical therapy. Animal models and non-mammalian systems have been developed to

  6. Using Soxhlet Ethanol Extraction to Produce and Test Plant Material (Essential Oils for Their Antimicrobial Properties

    Directory of Open Access Journals (Sweden)

    James Redfern

    2013-11-01

    Full Text Available As the issue of antimicrobial resistance continues to grow, there is a renewed interest in deriving antimicrobial products from natural compounds, particularly extracts from plant materials. This paper describes how essential oil can be extracted from the common herb, thyme (Thymus vulgaris in the classroom. Subsequently, the extract can be tested for its antimicrobial activity. A number of variables are suggested.

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

    Science.gov (United States)

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

    2012-01-01

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

  8. DETERMINATION OF ANTIMICROBIAL ACTIVITY OF ETHANOLIC EXTRACTS FROM SOME KINDS OF RAW MATERIALS WITH TANNINS

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    Boyko NN

    2015-04-01

    Full Text Available This paper presents data about determination of antimicrobial activity of extracts from some kinds of raw materials (13 plants with tannins. It was determined some kinds of technological parameters of extracts (concentration of total solids and density. A simple to use valuation method of antimicrobial properties of extracts – well method has been suggested and applied; for quantitative estimation of antimicrobial activity of extracts and compare them with each other, special mathematic method (vector algebra theory has been applied. It was determined parameters of antimicrobial properties of extracts: a complex indicator of medication antimicrobial activity for quantitative estimation of antimicrobial effect - A, and correlation coefficient - r (degree of similarity to the standard, which demonstrate the spectrum of antimicrobial activity of medication. It has been selected the most promising extracts that have the medium antimicrobial activity, which obtained from the root of bergenia crassifolia А=1.89; the root of potentilla erecta А=1.92; the bark of corylus avellana А=1.76; the leaf of cotinus coggygria А=2.21. Low level of antimicrobial activity has been demonstrated by the extract obtained from the cone of alnus incana А=0.78, r=0.58. It is noted antimicrobial properties of the solutions of tannin and gallic acids 0.5% m / m in 70% vol. ethanol, that showed respectively moderate and low strength antimicrobial properties: А=1.65, r=0.99 and А=1.26, r=0.91. This potentially allows to predict the antimicrobial properties of extracts from plants containing derivatives of tannin and gallic acids on their concentration in them. It has been shown in general that raw materials that contain different kinds of tannins have possibility to use in complex phytochemical medications as antimicrobial component.

  9. Current and future antimicrobial treatment of gonorrhoea - the rapidly evolving Neisseria gonorrhoeae continues to challenge.

    Science.gov (United States)

    Unemo, Magnus

    2015-01-01

    Neisseria gonorrhoeae has developed antimicrobial resistance (AMR) to all drugs previously and currently recommended for empirical monotherapy of gonorrhoea. In vitro resistance, including high-level, to the last option ceftriaxone and sporadic failures to treat pharyngeal gonorrhoea with ceftriaxone have emerged. In response, empirical dual antimicrobial therapy (ceftriaxone 250-1000 mg plus azithromycin 1-2 g) has been introduced in several particularly high-income regions or countries. These treatment regimens appear currently effective and should be considered in all settings where local quality assured AMR data do not support other therapeutic options. However, the dual antimicrobial regimens, implemented in limited geographic regions, will not entirely prevent resistance emergence and, unfortunately, most likely it is only a matter of when, and not if, treatment failures with also these dual antimicrobial regimens will emerge. Accordingly, novel affordable antimicrobials for monotherapy or at least inclusion in new dual treatment regimens, which might need to be considered for all newly developed antimicrobials, are essential. Several of the recently developed antimicrobials deserve increased attention for potential future treatment of gonorrhoea. In vitro activity studies examining collections of geographically, temporally and genetically diverse gonococcal isolates, including multidrug-resistant strains particularly with resistance to ceftriaxone and azithromycin, are important. Furthermore, understanding of effects and biological fitness of current and emerging (in vitro induced/selected and in vivo emerged) genetic resistance mechanisms for these antimicrobials, prediction of resistance emergence, time-kill curve analysis to evaluate antibacterial activity, appropriate mice experiments, and correlates between genetic and phenotypic laboratory parameters, and clinical treatment outcomes, would also be valuable. Subsequently, appropriately designed

  10. Inducible factors with antimicrobial activity after immune challenge in the haemolymph of Red Palm Weevil (Insecta).

    Science.gov (United States)

    Mastore, Maristella; Binda Rossetti, Simona; Giovannardi, Stefano; Scarì, Giorgio; Brivio, Maurizio F

    2015-05-01

    Insects are capable of innate immune responses elicited after microbial infection. In this process, the receptor-mediated recognition of foreign bodies and the subsequent activation of immunocompetent cells lead to the synthesis ex novo of a peptide pool with antimicrobial activity. We investigated the inducible immune response of a coleopteran, Rhynchophorus ferrugineus, challenged with both Gram-negative and Gram-positive bacteria. After immunization, we evaluated the presence of antimicrobial peptides using either biochemical analyses or microbiological techniques. The antimicrobial properties of the newly synthesized protein pool, detectable in haemolymph fractions of low molecular mass, showed strong antibacterial activity against various bacterial strains (Escherichia coli, Pseudomonas sp. OX1, Bacillus subtilis and Micrococcus luteus). In addition to the preliminary study of the mechanism of action of the pool of antimicrobial peptides, we also investigated its effects on bacterial cell walls by means of fluorescence microscopy and scanning electron microscopy. The data suggest that the main effects seem to be directed at destabilizing and damaging the bacterial wall. This study provides data that help us to understand some aspects of the inducible innate immunity in a system model that lacks anticipatory responses. However, the weevil has finely tuned its defensive strategies to counteract effectively microbial infection. PMID:25114180

  11. Critical challenges for EUV resist materials

    Energy Technology Data Exchange (ETDEWEB)

    Naulleau, Patrick P.; Anderson, Christopher N.; Baclea-an, Lorie-Mae; Denham, Paul; George, Simi; Goldberg, Kenneth A.; Jones, Gideon; McClinton, Brittany; Miyakawa, Ryan; Rekawa, Seno; Smith, Nathan

    2011-02-28

    Although Extreme ultraviolet lithography (EUVL) is now well into the commercialization phase, critical challenges remain in the development of EUV resist materials. The major issue for the 22-nm half-pitch node remains simultaneously meeting resolution, line-edge roughness (LER), and sensitivity requirements. Although several materials have met the resolution requirements, LER and sensitivity remain a challenge. As we move beyond the 22-nm node, however, even resolution remains a significant challenge. Chemically amplified resists have yet to demonstrate the required resolution at any speed or LER for 16-nm half pitch and below. Going to non-chemically amplified resists, however, 16-nm resolution has been achieved with a LER of 2 nm but a sensitivity of only 70 mJ/cm{sup 2}.

  12. Antimicrobial activity of transition metal acid MoO3 prevents microbial growth on material surfaces

    International Nuclear Information System (INIS)

    Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H2MoO4), which is based on molybdenum trioxide (MoO3). The modification of various materials (e.g. polymers, metals) with MoO3 particles or sol–gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments. Highlights: ► The presented modifications of materials surfaces with MoO3 are non-cytotoxic and decrease biofilm growth and bacteria transmission. ► The material is insensitive towards emerging resistances of bacteria. ► Strong potential to reduce spreading of infectious agents on inanimate surfaces.

  13. Nuclear material management: challenges and prospects

    International Nuclear Information System (INIS)

    The articles in this dossier were derived from the papers of the yearly S.F.E.N. convention, which took place in Paris, 12-13 March 2008. They deal with the new challenges and prospects in the field of nuclear material management, throughout the nuclear whole fuel cycle, namely: the institutional frame of nuclear materials management, the recycling, the uranium market, the enrichment market, the different scenarios for the management of civil nuclear materials, the technical possibilities of spent fuels utilization, the option of thorium, the convention on the physical protection of nuclear materials and installations, the characterisation of nuclear materials by nondestructive nuclear measurements, the proliferation from civil installations, the use of plutonium ( from military origin) and the international agreements. (N.C.)

  14. Structural materials challenges for fusion power systems

    International Nuclear Information System (INIS)

    Full text: Structural materials in a fusion power system must function in an extraordinarily demanding environment that includes various combinations of high temperatures, reactive chemicals, time-dependent thermal and mechanical stresses, and intense damaging radiation. The fusion neutron environment produces displacement damage equivalent to displacing every atom in the material about 150 times during its expected service life, and changes in chemical composition by transmutation reactions, which includes creation of reactive and insoluble gases. Fundamental materials challenges that must be resolved to effectively harness fusion power include (1) understanding the relationships between material strength, ductility and resistance to cracking, (2) development of materials with extraordinary phase stability, high-temperature strength and resistance to radiation damage, (3) establishment of the means to control corrosion of materials exposed to aggressive environments, (4) development of technologies for large-scale fabrication and joining, and (5) design of structural materials that provide for an economically attractive fusion power system while simultaneously achieving safety and environmental acceptability goals. The most effective approach to solve these challenges is a science-based effort that couples development of physics-based, predictive models of materials behavior with key experiments to validate the models. The U.S. Fusion Materials Sciences program is engaged in an integrated effort of theory, modeling and experiments to develop structural materials that will enable fusion to reach its safety, environmental and economic competitiveness goals. In this presentation, an overview of recent progress on reduced activation ferritic/martensitic steels, nanocomposited ferritic alloys, and silicon carbide fiber reinforced composites for fusion applications will be given

  15. ANTIMICROBIAL ACTIVITY OF MICROORGANISMS AND COLLOIDAL SILVER BASED ON COMPLEX MATERIALS

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    Voitenko O. Yu.

    2014-02-01

    Full Text Available The antimicrobial properties of complex materials containing ultradispersed silver particles directly formed in the Candida albіcans, Escherichia сolі, Pseudomonas fluorescens, and Bacillus cereus cell walls were investigated. Complex material based on pseudomonas was more active against gram-positive bacteria, the yeast like fungi based material was mainly active against colibacillus. After a cell-matrix treatment in a hypertonic solution or by acid hydrolysis, the antimicrobial properties of complex materials increased by 20—40%. In a liquid-phase medium, the complex materials with incorporated silver particles in composition with antibiotics strengthened anti-microbial properties of chloramphenicol, tetracycline and amoxiclav antibiotics with respect to E. faecalis, as well as penicillin antibiotics (ceftriaxone, cefotaxime, amoxicillin, amoxiclav against E. coli. The obtained data can serve as a basis for development of the new antibacterial and fungicide cells based materials impregnated with ultradispersed substances.

  16. Antimicrobial Polymeric Materials; Cellulose and m- Aramid Composite Fibers

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    Jaewoong Lee, Ph.D.

    2007-12-01

    Full Text Available Cellulose and m-aramid were dissolved in an ionic liquid, and dry-jet wet spinning was employed to prepare composite fibers which could be rendered antimicrobial through exposure to chlorine bleach. The small domains of the m-aramid allowed a much higher accessibility and degree of chlorination than has been reported even for 100% m-aramid fibers. The mechanical properties including denier, tenacity, and strain at break were evaluated. The chlorinated composite fiber inactivated both Gram-positive and Gram-negative bacteria. The antimicrobial activity was retained after repeated washing and recharging.

  17. Using Soxhlet Ethanol Extraction to Produce and Test Plant Material (Essential Oils) for Their Antimicrobial Properties †

    OpenAIRE

    James Redfern; Malcolm Kinninmonth; Dariel Burdass; Joanna Verran

    2014-01-01

    As the issue of antimicrobial resistance continues to grow, there is a renewed interest in deriving antimicrobial products from natural compounds, particularly extracts from plant materials. This paper describes how essential oil can be extracted from the common herb, thyme (Thymus vulgaris) in the classroom. Subsequently, the extract can be tested for its antimicrobial activity. A number of variables are suggested.

  18. Characteristics and antimicrobial activity of copper-based materials

    Science.gov (United States)

    Li, Bowen

    In this study, copper vermiculite was synthesized, and the characteristics, antimicrobial effects, and chemical stability of copper vermiculite were investigated. Two types of copper vermiculite materials, micron-sized copper vermiculite (MCV) and exfoliated copper vermiculite (MECV), are selected for this research. Since most of the functional fillers used in industry products, such as plastics, paints, rubbers, papers, and textiles prefer micron-scaled particles, micron-sized copper vermiculite was prepared by jet-milling vermiculite. Meanwhile, since the exfoliated vermiculite has very unique properties, such as high porosity, specific surface area, high aspect ratio of laminates, and low density, and has been extensively utilized as a functional additives, exfoliated copper vermiculite also was synthesized and investigated. The antibacterial efficiency of copper vermiculite was qualitatively evaluated by the diffusion methods (both liquid diffusion and solid diffusion) against the most common pathogenic species: Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), and Klebsiella pneumoniae (K. pneumoniae). The result showed that the release velocity of copper from copper vermiculite is very slow. However, copper vermiculite clearly has excellent antibacterial efficiency to S. aureus, K. pneumoniae and E. coli. The strongest antibacterial ability of copper vermiculite is its action on S. aureus. The antibacterial efficiency of copper vermiculite was also quantitatively evaluated by determining the reduction rate (death rate) of E. coli versus various levels of copper vermiculite. 10 ppm of copper vermiculite in solution is sufficient to reduce the cell population of E. coli, while the untreated vermiculite had no antibacterial activity. The slow release of copper revealed that the antimicrobial effect of copper vermiculite was due to the strong interactions between copper ions and bacteria cells. Exfoliated copper vermiculite has even stronger

  19. ASME Material Challenges for Advanced Reactor Concepts

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Ali Siahpush

    2013-07-01

    This study presents the material Challenges associated with Advanced Reactor Concept (ARC) such as the Advanced High Temperature Reactor (AHTR). ACR are the next generation concepts focusing on power production and providing thermal energy for industrial applications. The efficient transfer of energy for industrial applications depends on the ability to incorporate cost-effective heat exchangers between the nuclear heat transport system and industrial process heat transport system. The heat exchanger required for AHTR is subjected to a unique set of conditions that bring with them several design challenges not encountered in standard heat exchangers. The corrosive molten salts, especially at higher temperatures, require materials throughout the system to avoid corrosion, and adverse high-temperature effects such as creep. Given the very high steam generator pressure of the supercritical steam cycle, it is anticipated that water tube and molten salt shell steam generators heat exchanger will be used. In this paper, the ASME Section III and the American Society of Mechanical Engineers (ASME) Section VIII requirements (acceptance criteria) are discussed. Also, the ASME material acceptance criteria (ASME Section II, Part D) for high temperature environment are presented. Finally, lack of ASME acceptance criteria for thermal design and analysis are discussed.

  20. Structural materials challenges for advanced reactor systems

    Science.gov (United States)

    Yvon, P.; Carré, F.

    2009-03-01

    Key technologies for advanced nuclear systems encompass high temperature structural materials, fast neutron resistant core materials, and specific reactor and power conversion technologies (intermediate heat exchanger, turbo-machinery, high temperature electrolytic or thermo-chemical water splitting processes, etc.). The main requirements for the materials to be used in these reactor systems are dimensional stability under irradiation, whether under stress (irradiation creep or relaxation) or without stress (swelling, growth), an acceptable evolution under ageing of the mechanical properties (tensile strength, ductility, creep resistance, fracture toughness, resilience) and a good behavior in corrosive environments (reactor coolant or process fluid). Other criteria for the materials are their cost to fabricate and to assemble, and their composition could be optimized in order for instance to present low-activation (or rapid desactivation) features which facilitate maintenance and disposal. These requirements have to be met under normal operating conditions, as well as in incidental and accidental conditions. These challenging requirements imply that in most cases, the use of conventional nuclear materials is excluded, even after optimization and a new range of materials has to be developed and qualified for nuclear use. This paper gives a brief overview of various materials that are essential to establish advanced systems feasibility and performance for in pile and out of pile applications, such as ferritic/martensitic steels (9-12% Cr), nickel based alloys (Haynes 230, Inconel 617, etc.), oxide dispersion strengthened ferritic/martensitic steels, and ceramics (SiC, TiC, etc.). This article gives also an insight into the various natures of R&D needed on advanced materials, including fundamental research to investigate basic physical and chemical phenomena occurring in normal and accidental operating conditions, lab-scale tests to characterize candidate materials

  1. Material challenge for flexible organic devices

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    Jay Lewis

    2006-04-01

    Full Text Available Outside of the active device layers, there are a variety of requisite functional layers in flexible organic electronic devices. Whether the application is in displays, lighting, integrated circuits, or photovoltaics, there are materials challenges in implementing flexible and/or organic devices into practical applications. We highlight two topics that are common to most flexible electronic technologies. First, we describe the difficulty in developing suitable permeation barriers on polymer substrates, the approaches being taken to solve this problem, and their current status. Second, we highlight the limited mechanical ruggedness of brittle inorganic films and present approaches for improving overall device flexibility.

  2. Structural Materials: New Challenges, Manufacturing and Performance

    International Nuclear Information System (INIS)

    Important criteria of innovative fast reactors and advanced fuel cycle initiatives are improved efficiency, economic competitiveness and reduction of waste. To reach these goals and keep high safety standards, at least at the level of currently operating nuclear reactors, key issues are the availability of suitable structural materials and their performance assessment. The authors, on the basis of the wealth of experience gained in the European Union, India and Japan, aim to define the challenges and current status of material development and set the agenda for R and D in the coming years and decades. It is hoped that the joint perspective would enable realizing the expected criteria of sustainability envisaged through sodium cooled fast reactors and closed fuel cycles. (author)

  3. Selection and challenges for LFR reactor materials

    International Nuclear Information System (INIS)

    Nuclear energy using Fast GenIV reactors can fulfil future demands concerning CO2 free, base load capability and sustainability. One of the most promising coolants especially due to its high thermal inertia is liquid lead (Pb). Since several years researches all over the world investigate this coolant and its impact on the reactor design and by that on the materials to be selected. The LEADER project, a follow up of ELSY, aims to design a prototypical demonstrator ALFRED and to continue with several design related aspects of the ELFR reactor. For a demonstrator the criteria of material selection are somewhat different to a commercial type like the ELFR. Material selection for ELFR of course considers all the aspects relevant for ALFRED plus the targeted burn up and the expected total dpa related damage especially of the fuel pins. In the past compatibility of structural material (steels like 316L, T91 and 15-15Ti (1.4970)) that can be employed for Pb cooled fast nuclear reactors were investigated in several EU projects like EUROTRANS and worldwide. Solubility of steel alloying elements like Ni, Fe, Cr is the driving force for the reduced corrosion resistance in contact with Pb. In-situ oxidation is the acknowledged measure to protect steels in Pb up to certain temperatures that are material dependent. Based on experiments and the derived temperature limits the average core outlet temperatures of ALFRED and the ELFR are set to 480 C. The most challenging conditions with respect to temperature are at the fuel assembly and the heat exchangers. For both, thin stable oxide scales with negligible reduction in heat transfer are the requested protection method. This presentation will give an overview on the selected materials for ALFRED and ELFR considering, beside pure compatibility, the influence of mechanical interaction like creep and fretting. (orig.)

  4. Materials challenges and testing for supply of energy and resources

    Energy Technology Data Exchange (ETDEWEB)

    Boellinghaus, Thomas; Lexow, Juergen (eds.) [Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin (Germany); Kishi, Teruo [National Inst. for Materials Science, Tsukuba, Ibaraki (Japan); Kitagawa, Masaki [Isobe Mihamaku, Chiba (Japan)

    2012-07-01

    One major goal of the World Materials Research Institute Forum - WMRIF is to promote young scientists in the field of materials science and engineering. To enhance the international knowledge exchange between young postdoctoral scientists all over the world, WMRIF meanwhile regularly organizes joint workshops among the member institutes. These workshops also represent an increasingly appreciated platform to get known to each other and to build co-operations. For such workshops, various topics are selected, pointing to future perspectives and challenges in the field of materials science and engineering. This book contains the following contributions: I. Materials challenges for nuclear fission and fusion - Examination of Dust Particles from Present-Day Controlled Fusion Devices (Elzbieta Fortuna-Zalesna); Quantitative microstructural investigation of neutron-irradiated RAFM steel for nuclear fusion applications (Oliver J. Weiss), Controlling Welding Residual Stresses by means of Alloy Design (Arne Kromm); Degradation Mechanism of Creep Strength Enhanced Ferritic Steels for Power Plants (Kota Sawada); Electrochemical studies on pitting corrosion on Cr13 steel exposed to CO{sub 2} and artificial brine with high chloride concentration (Oleksandra Yevtushenko); Development of {sup 10}B{sub 2}O{sub 3} processing for use as a neutron conversion materials (Lars F. Voss). II. Materials challenges for water supply Water overlayers on Cu(110) studied by van der Waals density Functional (Sheng Meng). III. Challenges in conclusive, realistic and system oriented materials testing - Employment of high Resolution RBS to characterize ultrathin transparent electrode in high efficiency GaN based Light Emitting Diode (Grace Huiqi Wang); A possible route to the quantification of piezoresponse force microscopy through correlation with electron backscatter diffraction (Tim L. Burnett); High Resolution Analysis of Tungsten Doped Amorphous Carbon thin Films (Marcin Rasinski); Electron

  5. Materials challenges and testing for supply of energy and resources

    International Nuclear Information System (INIS)

    One major goal of the World Materials Research Institute Forum - WMRIF is to promote young scientists in the field of materials science and engineering. To enhance the international knowledge exchange between young postdoctoral scientists all over the world, WMRIF meanwhile regularly organizes joint workshops among the member institutes. These workshops also represent an increasingly appreciated platform to get known to each other and to build co-operations. For such workshops, various topics are selected, pointing to future perspectives and challenges in the field of materials science and engineering. This book contains the following contributions: I. Materials challenges for nuclear fission and fusion - Examination of Dust Particles from Present-Day Controlled Fusion Devices (Elzbieta Fortuna-Zalesna); Quantitative microstructural investigation of neutron-irradiated RAFM steel for nuclear fusion applications (Oliver J. Weiss), Controlling Welding Residual Stresses by means of Alloy Design (Arne Kromm); Degradation Mechanism of Creep Strength Enhanced Ferritic Steels for Power Plants (Kota Sawada); Electrochemical studies on pitting corrosion on Cr13 steel exposed to CO2 and artificial brine with high chloride concentration (Oleksandra Yevtushenko); Development of 10B2O3 processing for use as a neutron conversion materials (Lars F. Voss). II. Materials challenges for water supply Water overlayers on Cu(110) studied by van der Waals density Functional (Sheng Meng). III. Challenges in conclusive, realistic and system oriented materials testing - Employment of high Resolution RBS to characterize ultrathin transparent electrode in high efficiency GaN based Light Emitting Diode (Grace Huiqi Wang); A possible route to the quantification of piezoresponse force microscopy through correlation with electron backscatter diffraction (Tim L. Burnett); High Resolution Analysis of Tungsten Doped Amorphous Carbon thin Films (Marcin Rasinski); Electron Microscopy Studies on Oxide

  6. Structural materials: New challenges, manufacturing and performance

    International Nuclear Information System (INIS)

    Full texct: This paper reviews international perspectives on materials, manufacturing and performance on structural materials for fast reactors. It is recognized that fast reactors with closed fuel cycle shall play an eminent and major role to realize energy sustainability. Large scale exploitation of fast reactors shall require meeting of sustainability requirements such as economic competitiveness, safe and optimized waste management, increased proliferation resistance, improved use of uranium and thorium and enhanced efficiency. The designers of these reactors along with material specialists have a key role in meeting the above mentioned criteria of sustainability. The paper shall describe features of advanced sodium cooled fast reactors and the resulting requirements on the performance of the structural materials. The choice of the fuel governs the cladding material for these reactors. Considering the choice as oxide, carbide, metallic with or without minor actinides; cladding materials are chosen based on performance modeling, available experience and expertise. Improved varieties of 316 austenitic stainless steels and oxide dispersion ferritice-martensitic steels emerge as front runners to meet the requirements. The developments in Ti modified 316 austenitic stainless steels give enough confidence to take these fuels to burn-up of 120,000 MWd/t. It is inferred that the target burn-up of 250,000 MWd/t would only be achieved with oxide dispersion strengthened iron- chromium base steels. Research and development of modified austenitic stainless steels and ODS alloys in Japan, Europe and India would be described in the paper. For achieving high burn-up of 250,000 MWd/t, ferritic-martensitic steel has emerged as the choice for the wrapper material. The current status of development and the challenges shall be described in the paper. In particular, the European contribution to this paper addresses the development and performance assessment of the preferred

  7. The transport of radioactive materials - Future challenges

    International Nuclear Information System (INIS)

    The International Atomic Energy Agency (IAEA) Regulations for the Safe Transport of Radioactive Materials, TS-R-1, set the standards for the packages used in the transport of radioactive materials under both normal and accident conditions. Transport organisations are also required to implement Radiation Protection Programmes to control radiation dose exposure to both workers and the public. The industry has now operated under this regulatory regime safely and efficiently for nearly 50 years. It is vital that this record be maintained in the future when the demands on the transport industry are increasing. Nuclear power is being called upon more and more to satisfy the world's growing need for sustainable, clean and affordable electricity and there will be a corresponding demand for nuclear fuel cycle services. There will also be a growing need for other radioactive materials, notably large sources such as Cobalt 60 sources for a range of important medical and industrial uses, as well as radio-pharmaceuticals. A reliable transport infrastructure is essential to support all these industry sectors and the challenge will be to ensure that this can be maintained safely and securely in a changing world where public and political concerns are increasing. This paper will discuss the main issues which need to be addressed. The demand for uranium has led to increased exploration and the development of mines in new locations far removed from the demand centres. This inevitably leads to more transport, sometimes from areas potentially lacking in transport infrastructure, service providers, and experience. The demand for sources for medical applications will also increase, particularly from the rapidly developing regions and this will also involve new transport routes and increased traffic. This raises a variety of issues concerning the ability of the transport infrastructure to meet the future challenge, particularly in an environment where there already exists reluctance on

  8. Designing antimicrobial bioactive glass materials with embedded metal ions synthesized by the sol–gel method

    International Nuclear Information System (INIS)

    Bioactive glasses (SiO2–P2O5–CaO) having tailored concentrations of different biocide metal ions (copper or silver) were produced by the sol–gel method. All the particles release phosphorous ions when immersed in water and simulated body fluid (SBF). Moreover, a surface layer of polycrystalline hydroxy-carbonate apatite was formed on the particle surfaces after 10 day immersion in SBF as confirmed by X-ray diffraction and scanning electron microscopy (SEM) showing the bioactive materials. Samples with embedded either copper or silver ions were able to further release the biocide ions with a release rate that depends on the metal embedded and the dissolution medium: water or SBF. This biocide ion release from the samples explains the antimicrobial effect of our active particles against Escherichia coli DH5α ampicillin-resistant (Gram-negative) and Streptococcus mutans (Gram-positive) as determined by the Minimum Bactericidal Concentration (MBC) method. The antimicrobial behavior of the particles depends on the bacteria and the biocide ion used. Noteworthy, although samples with copper are able to release more metal ion than samples with silver, they present higher MBC showing the high effect of silver against these bacteria. - Highlights: • Copper and silver act as antimicrobial additives in bioactive glass materials. • Silver is more toxic than copper ions in these bioactive materials. • Sol–gel method allows the synthesis of antimicrobial bioactive materials

  9. Designing antimicrobial bioactive glass materials with embedded metal ions synthesized by the sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Palza, Humberto, E-mail: hpalza@ing.uchile.cl [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile); Escobar, Blanca; Bejarano, Julian [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile); Bravo, Denisse [Departamento de Patología, Facultad de Odontología, Universidad de Chile, Santiago (Chile); Diaz-Dosque, Mario [Departamento de Ciencias Básicas y Comunitarias, Facultad de Odontología, Universidad de Chile, Santiago (Chile); Perez, Javier [Departamento de Ingeniería Química y Biotecnología, Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Santiago (Chile)

    2013-10-15

    Bioactive glasses (SiO{sub 2}–P{sub 2}O{sub 5}–CaO) having tailored concentrations of different biocide metal ions (copper or silver) were produced by the sol–gel method. All the particles release phosphorous ions when immersed in water and simulated body fluid (SBF). Moreover, a surface layer of polycrystalline hydroxy-carbonate apatite was formed on the particle surfaces after 10 day immersion in SBF as confirmed by X-ray diffraction and scanning electron microscopy (SEM) showing the bioactive materials. Samples with embedded either copper or silver ions were able to further release the biocide ions with a release rate that depends on the metal embedded and the dissolution medium: water or SBF. This biocide ion release from the samples explains the antimicrobial effect of our active particles against Escherichia coli DH5α ampicillin-resistant (Gram-negative) and Streptococcus mutans (Gram-positive) as determined by the Minimum Bactericidal Concentration (MBC) method. The antimicrobial behavior of the particles depends on the bacteria and the biocide ion used. Noteworthy, although samples with copper are able to release more metal ion than samples with silver, they present higher MBC showing the high effect of silver against these bacteria. - Highlights: • Copper and silver act as antimicrobial additives in bioactive glass materials. • Silver is more toxic than copper ions in these bioactive materials. • Sol–gel method allows the synthesis of antimicrobial bioactive materials.

  10. Materials Challenges for Automotive PEM Fuel Cells

    Science.gov (United States)

    Gasteiger, Hubert

    2004-03-01

    Over the past few years, significant R efforts aimed at meeting the challenging cost and performance targets required for the use of Polymer Electrolyte Membrane (PEM) fuel cells in automotive applications. Besides engineering advances in bipolar plate materials and design, the optimization of membrane-electrode assemblies (MEAs) was an important enabler in reducing the cost and performance gaps towards commercial viability for the automotive market. On the one hand, platinum loadings were reduced from several mgPt/cm2MEA [1] to values of 0.5-0.6 mgPt/cm2MEA in current applications and loadings as low as 0.25 mgPt/cm2MEA have been demonstrated on the research level [2]. On the other hand, implementation of thin membranes (20-30 micrometer) [3, 4] as well as improvements in diffusion medium materials, essentially doubled the achievable power density of MEAs to ca. 0.9 W/cm2MEA (at 0.65 V) [5], thereby not only reducing the size of a PEMFC fuel cell system, but also reducing its overall materials cost (controlled to a large extent by membrane and Pt-catalyst cost). While this demonstrated a clear path towards automotive applications, a renewed focus of R efforts is now required to develop materials and fundamental materials understanding to assure long-term durability of PEM fuel cells. This presentation therefore will discuss the state-of-the-art knowledge of catalyst, catalyst-support, and membrane degradation mechanisms. In the area of Pt-catalysts, experience with phosphoric acid fuel cells (PAFCs) has shown that platinum sintering leads to long-term performance losses [6]. While this is less critical at the lower PEMFC operating temperatures (200C), very little is known about the dependence of Pt-sintering on temperature, cell voltage, and catalyst type (i.e., Pt versus Pt-alloys) and will be discussed here. Similarly, carbon-support corrosion can contribute significantly to voltage degradation in PAFCs [7], and even in the PEMFC environment more corrosion

  11. Coated conductors for power applications: materials challenges

    International Nuclear Information System (INIS)

    This manuscript reports on the recent progress and the remaining materials challenges in the development of coated conductors (CCs) for power applications and magnets, with a particular emphasis on the different initiatives being active at present in Europe. We first summarize the scientific and technological scope where CCs have been raised as a complex technology product and then we show that there exists still much room for performance improvement. The objectives and CC architectures being explored in the scope of the European project EUROTAPES are widely described and their potential in generating novel breakthroughs emphasized. The overall goal of this project is to create synergy among academic and industrial partners to go well beyond the state of the art in several scientific issues related to CCs’ enhanced performances and to develop nanoengineered CCs with reduced costs, using high throughput manufacturing processes which incorporate quality control tools and so lead to higher yields. Three general application targets are considered which will require different conductor architectures and performances and so the strategy is to combine vacuum and chemical solution deposition approaches to achieve the targeted goals. A few examples of such approaches are described related to defining new conductor architectures and shapes, as well as vortex pinning enhancement through novel paths towards nanostructure generation. Particular emphasis is made on solution chemistry approaches. We also describe the efforts being made in transforming the CCs into assembled conductors and cables which achieve appealing mechanical and electromagnetic performances for power systems. Finally, we briefly mention some outstanding superconducting power application projects being active at present, in Europe and worldwide, to exemplify the strong advances in reaching the demands to integrate them in a new electrical engineering paradigm. (paper)

  12. Coated conductors for power applications: materials challenges

    Science.gov (United States)

    Obradors, Xavier; Puig, Teresa

    2014-04-01

    This manuscript reports on the recent progress and the remaining materials challenges in the development of coated conductors (CCs) for power applications and magnets, with a particular emphasis on the different initiatives being active at present in Europe. We first summarize the scientific and technological scope where CCs have been raised as a complex technology product and then we show that there exists still much room for performance improvement. The objectives and CC architectures being explored in the scope of the European project EUROTAPES are widely described and their potential in generating novel breakthroughs emphasized. The overall goal of this project is to create synergy among academic and industrial partners to go well beyond the state of the art in several scientific issues related to CCs’ enhanced performances and to develop nanoengineered CCs with reduced costs, using high throughput manufacturing processes which incorporate quality control tools and so lead to higher yields. Three general application targets are considered which will require different conductor architectures and performances and so the strategy is to combine vacuum and chemical solution deposition approaches to achieve the targeted goals. A few examples of such approaches are described related to defining new conductor architectures and shapes, as well as vortex pinning enhancement through novel paths towards nanostructure generation. Particular emphasis is made on solution chemistry approaches. We also describe the efforts being made in transforming the CCs into assembled conductors and cables which achieve appealing mechanical and electromagnetic performances for power systems. Finally, we briefly mention some outstanding superconducting power application projects being active at present, in Europe and worldwide, to exemplify the strong advances in reaching the demands to integrate them in a new electrical engineering paradigm.

  13. Electrospun antimicrobial hybrid mats: Innovative packaging material for meat and meat-products.

    Science.gov (United States)

    Amna, Touseef; Yang, Jieun; Ryu, Kyeong-Seon; Hwang, I H

    2015-07-01

    To prevent the development and spread of spoilage/pathogenic microorganisms via meat foodstuffs, antimicrobial nanocomposite packaging can serve as a potential alternative. The objective of this study was to develop a new class of antimicrobial hybrid packaging mat composed of biodegradable polyurethane supplemented with virgin olive oil and zinc oxide via electrospinning. Instead of mixing antimicrobial compounds directly with food, incorporation in packaging materials allows the functional effect at food surfaces where microbial activity is localized. The nanofibers were characterized by SEM, EDX, XRD and TEM. The antibacterial activity was tested against two common foodborne pathogens viz., Staphylococcus aureus and Salmonella typhimurium. The present results indicated that incorporation of olive oil in the polymer affected morphology of PU nanofibers and nanocomposite packaging were able to inhibit growth of pathogens. Thus; as-spun mat can be used as prospective antimicrobial packaging, which potentially reduces contamination of meat/meat-products. Moreover, introduced biodegradable packaging for meat products could serve to replace PVC films and simultaneously help to protect natural environment. PMID:26139931

  14. Nisin as a Food Preservative: Part 2: Antimicrobial Polymer Materials Containing Nisin.

    Science.gov (United States)

    Gharsallaoui, Adem; Joly, Catherine; Oulahal, Nadia; Degraeve, Pascal

    2016-06-10

    Nisin is the only bacteriocin approved as a food preservative because of its antibacterial effectiveness and its negligible toxicity for humans. Typical problems encountered when nisin is directly added to foods are mainly fat adsorption leading to activity loss, heterogeneous distribution in the food matrix, inactivation by proteolytic enzymes, and emergence of resistance in normally sensitive bacteria strains. To overcome these problems, nisin can be immobilized in solid matrices that must act as diffusional barriers and allow controlling its release rate. This strategy allows maintaining a just sufficient nisin concentration at the food surface. The design of such antimicrobial materials must consider both bacterial growth kinetics but also nisin release kinetics. In this review, nisin incorporation in polymer-based materials will be discussed and special emphasis will be on the applications and properties of antimicrobial food packaging containing this bacteriocin. PMID:25674671

  15. Evaluation of antimicrobial efficacy of various root canal filling materials for primary teeth.

    Science.gov (United States)

    Pabla, T; Gulati, M S; Mohan, U

    1997-12-01

    Four materials viz. zinc oxide-eugenol, iodoform paste, Kri paste, Maisto's paste and Vitapex (Calcium hydroxide + iodoform) were tested for their antibacterial effect against the aerobic and anerobic bacteria, viz. Staphylococcus aureus, Streptococcus viridans, Streptococcus faecalis, Bacteroides melaninogenicus and mixed bacterial culture; obtained from infected non-vital deciduous anterior teeth. The antimicrobial sensitivity was checked on BHI-agar plates using well method. The results showed that all the 4 materials were distinctly different from each other in their antimicrobial activity. Maisto's paste was invariably the superior most in its antibacterial efficacy (in comparison to all the 5 micro-organism strains). Iodoformized zincoxide eugenol appeared to be the second best followed by Kri paste. Vitapex showed the least antibacterial activity. PMID:10635127

  16. Photovoltaic materials: Present efficiencies and future challenges.

    Science.gov (United States)

    Polman, Albert; Knight, Mark; Garnett, Erik C; Ehrler, Bruno; Sinke, Wim C

    2016-04-15

    Recent developments in photovoltaic materials have led to continual improvements in their efficiency. We review the electrical characteristics of 16 widely studied geometries of photovoltaic materials with efficiencies of 10 to 29%. Comparison of these characteristics to the fundamental limits based on the Shockley-Queisser detailed-balance model provides a basis for identifying the key limiting factors, related to efficient light management and charge carrier collection, for these materials. Prospects for practical application and large-area fabrication are discussed for each material. PMID:27081076

  17. Development of a new antimicrobial material for wound dressing

    OpenAIRE

    Pinho, Eva Patrícia Paiva Santos

    2014-01-01

    Tese de doutoramento em Engenharia Biomédica Nowadays, wound dressings are complex materials that, behind the mechanical protection, are also capable of interacting with the injury tissue. These complex products improve the healing process by maintaining suitable conditions, allowing skin to establish integrity with appropriate cosmetic results. The incidence of chronic wounds related with diseases, population ageing, and tissue infection caused by multi-resistant strains of ba...

  18. Antimicrobial Performance of Two Different Packaging Materials on the Microbiological Quality of Fresh Salmon

    OpenAIRE

    Manuela Rollini; Tim Nielsen; Alida Musatti; Sara Limbo; Luciano Piergiovanni; Pilar Hernandez Munoz; Rafael Gavara

    2016-01-01

    In the present research the antimicrobial activity of two active packaging materials on the spoilage microbiota of fresh salmon fillets was tested. A PET-coated film (PET: Polyethylene Terephthalate) containing lysozyme and lactoferrin was tested in parallel with a carvacrol-coextruded multilayer film. Salmon fillet samples were stored up to four days at 0 and 5 °C, comparatively. The carvacrol multilayer film was found effective in preventing mesophiles and psychrotrophs at shorter storage t...

  19. Modified Cellulosic Materials with Antioxidant and AntimicrobialProperties for Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Anamaria Irimia

    2015-04-01

    Full Text Available Elaboration of a two steps physico-chemical process to obtain antimicrobial and antioxidant materials. A two-step process was used for modification of a cellulose/chitin mix fiber (CCfirst an enzymatic activation with a commercial cellulase enzyme was applied and then a coupling reaction with phenolic antioxidants such as p-hydroxybenzoic acid (HBA,gallicacid(GA and eugenol (Eu was carried out to evolve antimicrobial and antioxidant properties. Both the enzyme activated and the subsequently modified with antioxidant moieties samples were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy scanning electron microscopy and thermogravimetry. Furthermore, the antioxidant and antibacterial capacities were tested. All obtained results confirm the morphological and structural changes on the fiber surface after the twostep procedure of modification. Based on the XPS results, the modification degrees of the superficial layers of the fibers varied between 35 and 43%. Both the antimicrobial and radical scavenging activities were up to 100% and the order of the antioxidant activity can be written as: CC/Eu > CC/ GA > CC/HBA. Materials with these functionalities can be widely applied in the dermo-cosmetic field to protect the skin from oxidative stress, as transdermal patches which could be effectively used as a material in wound dressings.

  20. Antimicrobial activity of transition metal acid MoO{sub 3} prevents microbial growth on material surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zollfrank, Cordt, E-mail: cordt.zollfrank@ww.uni-erlangen.de [University of Erlangen-Nuremberg, Department of Materials Science and Engineering 3-Glass and Ceramics, Martensstr. 5, D-91058 Erlangen (Germany); Gutbrod, Kai [University of Erlangen-Nuremberg, Department of Materials Science and Engineering 3-Glass and Ceramics, Martensstr. 5, D-91058 Erlangen (Germany); Wechsler, Peter [LEONI Kabel GmbH, Stieberstrasse 5, D-91154 Roth (Germany); Guggenbichler, Josef Peter [Laboratory for the Development of Healthcare Products, Leitweg 23, A-6345 Koessen (Austria)

    2012-01-01

    Serious infectious complications of patients in healthcare settings are often transmitted by materials and devices colonised by microorganisms (nosocomial infections). Current strategies to generate material surfaces with an antimicrobial activity suffer from the consumption of the antimicrobial agent and emerging multidrug-resistant pathogens amongst others. Consequently, materials surfaces exhibiting a permanent antimicrobial activity without the risk of generating resistant microorganisms are desirable. This publication reports on the extraordinary efficient antimicrobial properties of transition metal acids such as molybdic acid (H{sub 2}MoO{sub 4}), which is based on molybdenum trioxide (MoO{sub 3}). The modification of various materials (e.g. polymers, metals) with MoO{sub 3} particles or sol-gel derived coatings showed that the modified materials surfaces were practically free of microorganisms six hours after contamination with infectious agents. The antimicrobial activity is based on the formation of an acidic surface deteriorating cell growth and proliferation. The application of transition metal acids as antimicrobial surface agents is an innovative approach to prevent the dissemination of microorganisms in healthcare units and public environments. Highlights: Black-Right-Pointing-Pointer The presented modifications of materials surfaces with MoO{sub 3} are non-cytotoxic and decrease biofilm growth and bacteria transmission. Black-Right-Pointing-Pointer The material is insensitive towards emerging resistances of bacteria. Black-Right-Pointing-Pointer Strong potential to reduce spreading of infectious agents on inanimate surfaces.

  1. High throughput screening of perfumery raw materials for antimicrobial properties.

    Science.gov (United States)

    Rey, Sylvain; Anziani, Pauline; Seyfried, Markus

    2014-01-01

    A microdilution protocol was developed and automated using a liquid handling station, allowing the determination of minimum inhibitory concentrations (MIC) of hydrophobic raw materials commonly used in the perfume industry (essential oils and synthetic chemicals). Tests were performed in 96-well microtiter plates against standard bacterial test strains and skin isolates involved in underarm malodor. The comparison with data previously reported in the literature indicated that the protocol was suitable, yielding MIC values that were in general agreement with those derived from manual test methods. For the majority of active test compounds, results showed a pronounced difference in susceptibility pattern between the Gram-positive and Gram-negative test strains used in this study. For a group of acyclic aliphatic aldehydes, a structure-activity relationship depending on the chain length was found. PMID:24628279

  2. Materials Challenges for Advanced Combustion and Gasification Fossil Energy Systems

    Science.gov (United States)

    Sridhar, S.; Rozzelle, P.; Morreale, B.; Alman, D.

    2011-04-01

    This special section of Metallurgical and Materials Transactions is devoted to materials challenges associated with coal based energy conversion systems. The purpose of this introductory article is to provide a brief outline to the challenges associated with advanced combustion and advanced gasification, which has the potential of providing clean, affordable electricity by improving process efficiency and implementing carbon capture and sequestration. Affordable materials that can meet the demanding performance requirements will be a key enabling technology for these systems.

  3. Challenges in structural materials for thermal reactors

    International Nuclear Information System (INIS)

    The safe, reliable and economic operation of nuclear power plants is critically dependent on good performance of materials. Material selection is one of the most important steps in the design of the engineering components. Functional requirements and operating conditions such as stress, temperature and environment dictate the choice of materials and their properties. Criteria for selection of materials for non-nuclear components include mechanical properties (strength-ductility-toughness), corrosion properties (resistance to uniform and localized corrosion), fabricability (forming-welding-heat treatment) and cost. Additional considerations for nuclear components include neutron absorption, induced radioactivity and resistance to radiation damage. Nuclear core components are continuously subjected to bombardment by fast neutrons. Important effects of fast neutron irradiation on properties of materials are : (i) change in mechanical properties by irradiation hardening and irradiation embrittlement (ii) dimensional changes by irradiation growth, irradiation creep and void swelling and (iii) change in corrosion properties like increase in corrosion rate and introduction of new corrosion mode. There are 2 types of thermal power reactors viz., Pressure Vessel Type (BWRs and PWRs) and Pressure Tube Type (PHWRs). A very wide range of materials are used for nuclear reactor components. These include carbon and low alloy steels, stainless steels (austenitic, martensitic, precipitation hardenable), nickel-base alloys (inconels, incoloys), zirconium base alloys, etc. Three most important classes of materials are : (1) Low alloy steels for Reactor Pressure Vessel : the main concerns are increase in Ductile-Brittle transition temperature (DBTT) and decrease in toughness due to neutron irradiation. (2) Zirconium Alloys for Reactor Core Components : main concerns are Delayed Hydride cracking (DHC) and change in dimensions due to Irradiation Creep and Growth. (3) Stainless Steels

  4. A unique in vivo approach for investigating antimicrobial materials utilizing fistulated animals

    Science.gov (United States)

    Berean, Kyle J.; Adetutu, Eric M.; Zhen Ou, Jian; Nour, Majid; Nguyen, Emily P.; Paull, David; McLeod, Jess; Ramanathan, Rajesh; Bansal, Vipul; Latham, Kay; Bishop-Hurley, Greg J.; McSweeney, Chris; Ball, Andrew S.; Kalantar-Zadeh, Kourosh

    2015-06-01

    Unique in vivo tests were conducted through the use of a fistulated ruminant, providing an ideal environment with a diverse and vibrant microbial community. Utilizing such a procedure can be especially invaluable for investigating the performance of antimicrobial materials related to human and animal related infections. In this pilot study, it is shown that the rumen of a fistulated animal provides an excellent live laboratory for assessing the properties of antimicrobial materials. We investigate microbial colonization onto model nanocomposites based on silver (Ag) nanoparticles at different concentrations into polydimethylsiloxane (PDMS). With implantable devices posing a major risk for hospital-acquired infections, the present study provides a viable solution to understand microbial colonization with the potential to reduce the incidence of infection through the introduction of Ag nanoparticles at the optimum concentrations. In vitro measurements were also conducted to show the validity of the approach. An optimal loading of 0.25 wt% Ag is found to show the greatest antimicrobial activity and observed through the in vivo tests to reduce the microbial diversity colonizing the surface.

  5. Materials challenges for future nanoscale electronics

    International Nuclear Information System (INIS)

    Full text: Scaling of semiconductor technology (CMOS) has been the driving force for the success of information technology. However, as device dimensions continue to shrink into the nanometer length-scale regime, conventional semiconductor technology will be approaching fundamental physical limits. New strategies, including the use of novel materials and 1D-device concepts, innovative device architectures, and smart integration schemes need to be explored and assessed. They are crucial to extend current capabilities and maintain momentum beyond the end of the technology roadmap time frame (post-CMOS era). (author)

  6. Characterization and antimicrobial performance of nano silver coatings on leather materials

    Directory of Open Access Journals (Sweden)

    N. Lkhagvajav

    2015-03-01

    Full Text Available In this study, the characterization and the antimicrobial properties of nano silver (nAg coating on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg solutions prepared by the sol-gel method were measured. The formation of films from these solutions was characterized according to temperature by Differential Thermal Analysis-Thermogravimetry (DTA-TG equipment. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM. The antimicrobial performance of nAg coatings on leather materials to the test microorganisms as Escherichia coli, Staphylococcus aureus, Candida albicans and Aspergillius niger was evaluated by the application of qualitative (Agar overlay method and quantitative (percentage of microbial reduction tests. According to qualitative test results it was found that 20 μg/cm2 and higher concentrations of nAg on the leather samples were effective against all microorganisms tested. Moreover, quantitative test results showed that leather samples treated with 20 μg/cm2 of nAg demonstrated the highest antibacterial activity against E. coli with 99.25% bacterium removal, whereas a 10 μg/cm2 concentration of nAg on leather was enough to exhibit the excellent percentage reduction against S. aureus of 99.91%. The results are promising for the use of colloidal nano silver solution on lining leather as antimicrobial coating.

  7. Challenges in realizing ultraflat materials surfaces

    Directory of Open Access Journals (Sweden)

    Takashi Yatsui

    2013-12-01

    Full Text Available Ultraflat surface substrates are required to achieve an optimal performance of future optical, electronic, or optoelectronic devices for various applications, because such surfaces reduce the scattering loss of photons, electrons, or both at the surfaces and interfaces. In this paper, we review recent progress toward the realization of ultraflat materials surfaces. First, we review the development of surface-flattening techniques. Second, we briefly review the dressed photon–phonon (DPP, a nanometric quasiparticle that describes the coupled state of a photon, an electron, and a multimode-coherent phonon. Then, we review several recent developments based on DPP-photochemical etching and desorption processes, which have resulted in angstrom-scale flat surfaces. To confirm that the superior flatness of these surfaces that originated from the DPP process, we also review a simplified mathematical model that describes the scale-dependent effects of optical near-fields. Finally, we present the future outlook for these technologies.

  8. Materials challenges at the back end of the fuel cycle

    International Nuclear Information System (INIS)

    In this paper an attempt has been made to bring out the materials challenges in the back end activities of the fuel, and various issues related to problems associated with the use of current materials, development of newer alloys, future challenges associated with materials testing and inspection. For the implementation of several advanced materials and techniques a comprehensive programme for improving the reliability and integrity of the plant components needs to be established. As being proceeded in this path of development success will be seen in the continuous operation of the reprocessing plants with zero failure concept

  9. Emerging Infectious Diseases, Antimicrobial Resistance and Millennium Development Goals: Resolving the Challenges through One Health

    Directory of Open Access Journals (Sweden)

    G. V. Asokan

    2014-01-01

    Full Text Available Most emerging infectious diseases are zoonoses, which could severely hamper reaching the targets of millennium development goals (MDG. Five out of the total eight MDG’s are strongly associated with the Emerging Infectious Diseases (EIDs. Recent emergence and dissemination of drug-resistant pathogens has accelerated and prevent reaching the targets of MDG, with shrinking of therapeutic arsenal, mostly due to antimicrobial resistance (AMR. World Health Organization (WHO has identified AMR as 1 of the 3 greatest threats to global health. Until now, methicillin-resistant staphylococcus aureus (MRSA and vancomycin-resistant enterococci (VRE have been observed in hospital-acquired infections. In India, within a span of three years, New Delhi metallo-β-lactamase prevalence has risen from three percent in hospitals to twenty- fifty percent and is found to be colistin resistant as well. Routine use of antimicrobials in animal husbandry accounts for more than 50% in tonnage of all antimicrobial production to promote growth and prophylaxis. This has consequences to human health and environmental contamination with a profound impact on the environmental microbiome, resulting in resistance. Antibiotic development is now considered a global health crisis. The average time required to receive regulatory approval is 7.2 years. Moreover, the clinical approval success is only 16%. To overcome resistance in antimicrobials, intersectoral partnerships among medical, veterinary, and environmental disciplines, with specific epidemiological, diagnostic, and therapeutic approaches are needed. Joint efforts under “One Health”, beyond individual professional boundaries are required to stop antimicrobial resistance against zoonoses (EID and reach the MDG.

  10. Emerging Infectious Diseases, Antimicrobial Resistance and Millennium Development Goals: Resolving the Challenges through One Health

    OpenAIRE

    G. V. Asokan; R. K. Kasimanickam

    2014-01-01

    Most emerging infectious diseases are zoonoses, which could severely hamper reaching the targets of millennium development goals (MDG). Five out of the total eight MDG’s are strongly associated with the Emerging Infectious Diseases (EIDs). Recent emergence and dissemination of drug-resistant pathogens has accelerated and prevent reaching the targets of MDG, with shrinking of therapeutic arsenal, mostly due to antimicrobial resistance (AMR). World Health Organization (WHO has identified AMR a...

  11. Material challenges for the next generation of fission reactor systems

    International Nuclear Information System (INIS)

    The new generation of fission reactor systems wil require the deployment and construction of a series of advanced water cooled reactors as part of a package of measures to meet UK and European energy needs and to provide a near term non-fossil fuel power solution that addresses CO2 emission limits. In addition new longer term Generation IV reactor tye systems are being developed and evaluated to enhance safety, reliability, sustainability economics and proliferation resistance requirements and to meet alternative energy applications (outside of electricity generation) such as process heat and large scale hydrogen generation. New fission systems will impose significant challenges on materials supply and development. In the near term, because of the need to 'gear up' to large scale construction after decades of industrial hibernation/contraction and, in the longer term, because of the need for materials to operate under more challenging environments requiring the deployment and development of new alternative materials not yet established to an industrial stage. This paper investigates the materials challenges imposed by the new Generation III+ and Generation IV systems. These include supply and fabrication issues, development of new high temperature alloys and non-metallic materials, the use of new methods of manufacture and the best use of currently available resources and minerals. Recommendations are made as to how these materials challenges might be met and how governments, industry, manufacturers and researchers can all play their part. (orig.)

  12. Zwitterionic Cellulose Carbamate with Regioselective Substitution Pattern: A Coating Material Possessing Antimicrobial Activity.

    Science.gov (United States)

    Elschner, Thomas; Lüdecke, Claudia; Kalden, Diana; Roth, Martin; Löffler, Bettina; Jandt, Klaus D; Heinze, Thomas

    2016-04-01

    A polyzwitterion is synthesized by regioselective functionalization of cellulose possessing a uniform charge distribution. The positively charged ammonium group is present at position 6, while the negative charge of carboxylate is located at positions 2 and 3 of the repeating unit. The molecular structure of the biopolymer derivative is proved by NMR spectroscopy. This cellulose-based zwitterion is applied to several support materials by spin-coating and characterized by means of atomic force microscope, contact angle measurements, ellipsometry, and X-ray photoelectron spectroscopy. The coatings possess antimicrobial activity depending on the support materials (glass, titanium, tissue culture poly(styrene)) as revealed by confocal laser scanning microscopy and live/dead staining. PMID:26632022

  13. Materials challenges for the Supercritical Water-Cooled Reactor (SCWR)

    International Nuclear Information System (INIS)

    This paper discusses the materials requirements of the Supercritical Water-cooled Reactor (SCWR) which arise from its severe expected operating conditions: (i) Outlet Temperature (to 650 C); (ii) Pressure of 25 MPa for the coolant containment, (iii) Thermochemical stress in the presence of supercritical water, and (iv) Radiative damage (up to 150 dpa for the fast spectrum variant). These operating conditions are reviewed; the phenomenology of materials in the supercritical water environment that create the materials challenges is discussed; knowledge gaps are identified, and efforts to understand material behaviour under the operating conditions expected in the SCWR are described. (author)

  14. Emerging challenges and materials for thermal management of electronics

    Directory of Open Access Journals (Sweden)

    Arden L. Moore

    2014-05-01

    Full Text Available The rapid development of faster, cheaper, and more powerful computing has led to some of the most important technological and societal advances in modern history. However, the physical means associated with enhancing computing capabilities at the device and die levels have also created a very challenging set of circumstances for keeping electronic devices cool, a critical factor in determining their speed, efficiency, and reliability. With advances in nanoelectronics and the emergence of new application areas such as three-dimensional chip stack architectures and flexible electronics, now more than ever there are both needs and opportunities for novel materials to help address some of these pressing thermal management challenges. In this paper a number of cubic crystals, two-dimensional layered materials, nanostructure networks and composites, molecular layers and surface functionalization, and aligned polymer structures are examined for potential applications as heat spreading layers and substrates, thermal interface materials, and underfill materials in future-generation electronics.

  15. Achievement and New Challenges for High Performance Materials in Europe

    International Nuclear Information System (INIS)

    The European approach in the framework of nuclear energy advancement is described, in the light of such prominent objectives as safety, sustainability and transmutation of nuclear waste. The highlights are given on innovation and safety related design aspects of relevant fast neutron reactor component and systems. The materials requirements and related new challenges on materials for selected systems as decay heat removal systems, energy conversion systems, core components, etc., will be discussed and related European R&D programmes presented. (author)

  16. Improving the antimicrobial properties of titanium condenser material by surface modification using nanotechnology

    International Nuclear Information System (INIS)

    Biofouling is one of the major problems faced by condenser materials of power plants using seawater for cooling. Fouling control strategies in condensers include a combination of mechanical and chemical treatments like sponge ball cleaning, back washing and chlorination. In general, numerous studies have shown that no routine treatment regime can successfully keep the condenser tube clean over a period extending to years. Surface properties of the substratum influence initial adhesion and growth of bacterial cells on materials, modification of the surface for mitigating microbial attachment is the need of the hour. Metal nanoparticles are known to exhibit enhanced physical and chemical properties when compared to their bulk counter parts because of their high surface to volume ratios. Metals like copper are very toxic to microorganisms and effectively kill most of the microbes by blocking the respiratory enzyme. Copper alloys with their excellent resistance to biofouling are used extensively for marine applications. However, they are prone to localized corrosion initiation and consequently are getting replaced by extremely corrosion resistant titanium. Still, the inertness and biocompatibility of titanium makes it very susceptible to biofouling. Hence, this study attempts to use nano technology methods of surface modification of titanium using thin film of copper and also multilayers and bilayers of copper and nickel. This is aimed at improving the antimicrobial properties of this condenser pipe material. These nano structured thin films have been grown on titanium substrate using pulsed DC magnetron-sputtering and pulsed laser deposition. The thin films were characterized using Atomic Force Microscopy (AFM), Glancing Incidence X-ray Diffraction (GIXRD) and scanning electron microscopy (SEM with EDAX analysis). Antimicrobial properties were evaluated by exposure studies in seawater and bacterial cultures and by post exposure analysis using culture and

  17. OIL PALM FIBERS AS PAPERMAKING MATERIAL: POTENTIALS AND CHALLENGES

    OpenAIRE

    Wan Rosli Wan Daud; Kwei Nam Law

    2011-01-01

    This paper reviews the physical and chemical characteristics of fibers from the stem, fronds, and empty fruit bunches of oil palm tree in relation to their papermaking properties. Challenges regarding the use of this nonwood material for papermaking are raised, and possible solutions to them are given. A vision for the complete utilization of oil palm biomass is also outlined.

  18. OIL PALM FIBERS AS PAPERMAKING MATERIAL: POTENTIALS AND CHALLENGES

    Directory of Open Access Journals (Sweden)

    Wan Rosli Wan Daud

    2011-02-01

    Full Text Available This paper reviews the physical and chemical characteristics of fibers from the stem, fronds, and empty fruit bunches of oil palm tree in relation to their papermaking properties. Challenges regarding the use of this nonwood material for papermaking are raised, and possible solutions to them are given. A vision for the complete utilization of oil palm biomass is also outlined.

  19. Materials Challenges and Testing for Supply of Energy and Resources

    CERN Document Server

    Bollinghaus, Thomas

    2012-01-01

    One major goal of the World Materials Research Institute Forum - WMRIF is to promote young scientists in the field of materials science and engineering. To enhance the international knowledge exchange between young postdoctoral scientists all over the world, WMRIF meanwhile regularly organizes joint workshops among the member institutes. These workshops also represent an increasingly appreciated platform to get known to each other and to build co-operations. For such workshops, various topics are selected, pointing to future perspectives and challenges in the field of Materials Science and Eng

  20. Introducing the potential of antimicrobial materials for human and robotic spaceflight activities

    Science.gov (United States)

    Hahn, Claudia; Reitz, Guenther; Moeller, Ralf; Rettberg, Petra; Hans, Michael; Muecklich, Frank

    One major goal of space research is to discover past or present life on foreign planets such as Mars (Horneck et al., 2010). To detect extraterrestrial life on other planets it is important to prevent microbial contamination imported from the Earth, also known as forward contamination. Until now missions to Mars are solely progressed by robots like the Mars Science Laboratory mission with the Curiosity lander. The assembly of spacecraft components is performed in special bioburden controlled clean rooms. Nevertheless, the microbial diversity in these clean rooms is enormous (Vaishampayan et al., 2013). The propagation of microorganisms and in particular the spread of environmental and human-associated species can be facilitated through numerous exposure routes (e.g., air, personal contact, water, excretions, etc.). Besides robotic missions, on-board the International Space Station (ISS) and in (future) space vehicles for long-term journeys to special targets of astrobiological interests in the solar system, astronauts will have the unique opportunity for scientific exploration. The manned exploration of new environments (e.g. asteroids, Mars) require long-term residence in confined stations and habitats (e.g. space stations, spacecraft, vehicles). During these missions, the health of the crew members has to be protected, and the integrity of the materials and facilities should be carefully monitored (van Houdt et al., 2012). A major concern is the microbiological burden in enclosed environments, where human inhabitants are continuously exposed to potential harmful microorganisms over a long-duration, which may affect the health and performance of the human subjects (Horneck et al., 2010) in addition to potential risks by biofilm formation and biocorrosion of materials. In both scenarios, the application of antimicrobial surfaces is an encouraging approach to reduce microorganisms in a straightforward way. Antimicrobial agents and materials are characterized by

  1. Durability Challenges for Next Generation of Gas Turbine Engine Materials

    Science.gov (United States)

    Misra, Ajay K.

    2012-01-01

    Aggressive fuel burn and carbon dioxide emission reduction goals for future gas turbine engines will require higher overall pressure ratio, and a significant increase in turbine inlet temperature. These goals can be achieved by increasing temperature capability of turbine engine hot section materials and decreasing weight of fan section of the engine. NASA is currently developing several advanced hot section materials for increasing temperature capability of future gas turbine engines. The materials of interest include ceramic matrix composites with 1482 - 1648 C temperature capability, advanced disk alloys with 815 C capability, and low conductivity thermal barrier coatings with erosion resistance. The presentation will provide an overview of durability challenges with emphasis on the environmental factors affecting durability for the next generation of gas turbine engine materials. The environmental factors include gaseous atmosphere in gas turbine engines, molten salt and glass deposits from airborne contaminants, impact from foreign object damage, and erosion from ingestion of small particles.

  2. Outlook and challenges for hydrogen storage in nanoporous materials

    Science.gov (United States)

    Broom, D. P.; Webb, C. J.; Hurst, K. E.; Parilla, P. A.; Gennett, T.; Brown, C. M.; Zacharia, R.; Tylianakis, E.; Klontzas, E.; Froudakis, G. E.; Steriotis, Th. A.; Trikalitis, P. N.; Anton, D. L.; Hardy, B.; Tamburello, D.; Corgnale, C.; van Hassel, B. A.; Cossement, D.; Chahine, R.; Hirscher, M.

    2016-03-01

    Considerable progress has been made recently in the use of nanoporous materials for hydrogen storage. In this article, the current status of the field and future challenges are discussed, ranging from important open fundamental questions, such as the density and volume of the adsorbed phase and its relationship to overall storage capacity, to the development of new functional materials and complete storage system design. With regard to fundamentals, the use of neutron scattering to study adsorbed H2, suitable adsorption isotherm equations, and the accurate computational modelling and simulation of H2 adsorption are discussed. The new materials covered include flexible metal-organic frameworks, core-shell materials, and porous organic cage compounds. The article concludes with a discussion of the experimental investigation of real adsorptive hydrogen storage tanks, the improvement in the thermal conductivity of storage beds, and new storage system concepts and designs.

  3. Proteomic profile of hemolymph and detection of induced antimicrobial peptides in response to microbial challenge in Diatraea saccharalis (Lepidoptera: Crambidae).

    Science.gov (United States)

    Rocha, Iara Fernanda; Maller, Alexandre; de Cássia Garcia Simão, Rita; Kadowaki, Marina Kimiko; Angeli Alves, Luis Francisco; Huergo, Luciano Fernandes; da Conceição Silva, José Luis

    2016-04-29

    Insects are organisms extremely well adapted to diverse habitats, primarily due to their innate immune system, which provides them with a range of cellular and humoral responses against microorganisms. Lepidoptera hemolymph proteins involved in humoral responses are well known; however, there is a lack of knowledge about the sugarcane borer Diatraea saccharalis. In this present work, the hemolymph proteins of this pest insect were studied by applying proteomic methodologies. Two-dimensional electrophoresis (2-DE) gels of proteins extracted from naive larvae and larvae challenged with Escherichia coli (ATCC 11224) and Bacillus subtilis (ATCC 6623) showed an average of 300 spots, and 92 of these spots corresponded in all three 2-DE gels. Forty-one spots were excised and digested with trypsin and analyzed using mass spectrometry. After analysis, 10 proteins were identified, including some proteins of the immune system: β-defensin-like protein, Turandot A-like protein, attacin-like protein, peptidoglycan recognition protein and cyclophilin-like protein. Nine proteins were present in both experimental conditions; however, β-defensin-like protein was present only in hemolymph challenged by B. subtilis. Notably, attacin-like protein was strongly induced by challenge with E. coli, suggesting an immune response against the infection. However, antimicrobial activity was observed in the test zone of microbial growth inhibition of B. subtilis solely with the hemolymph extract of the larvae challenged with B. subtilis. We made for the first time a proteomic profile of the hemolymph of D. saccharalis in which it was possible to identify the presence of important proteins involved in the immune response. PMID:27012208

  4. Challenges of structural materials for innovative nuclear systems in Europe

    International Nuclear Information System (INIS)

    New fusion and fission reactors for generation IV are envisaged to operate at conditions well above the actual ones for commercial fission reactors. This type of reactor combined a high operation temperature with a high neutron dose and an aggressive coolant, which imply new challenges for structural materials. One of the key issues to assure the safety and feasibility of these new nuclear systems is the selection of the structural materials, especially for in core components. Beside the differences between them, especially the amount of transmutation He in fusion reactors, similar structural materials have been selected. Some of the selected materials are well characterized at least at medium temperatures, as conventional ferritic/martensitic steels, but the qualification for higher temperatures is needed. For other materials, as ODS steels, there is a need for a complete characterization and qualification. In this paper a review of the operating conditions and selected structural materials for generation IV and fusion reactors within Europe is made. The needs for a complete characterization of these candidate materials are identified in terms of high temperature behaviour, radiation damage and coolant compatibility. (author)

  5. Effects of composite antimicrobial peptides in weanling piglets challenged with deoxynivalenol: I. Growth performance, immune function, and antioxidation capacity.

    Science.gov (United States)

    Xiao, H; Wu, M M; Tan, B E; Yin, Y L; Li, T J; Xiao, D F; Li, L

    2013-10-01

    The mycotoxin deoxynivalenol (DON) is a food contaminant that leads to reduced feed intake and reduced BW gain, as well as organ impairment. On the other hand, antimicrobial peptides have been shown to have positive effects on growth performance, nutrient digestibility, and immune function. The purpose of this study was to investigate the protective effects of composite antimicrobial peptides (CAP) on piglets challenged with DON. After a 7-d adaptation period, 28 individually housed piglets (Duroc × Landrace × Large Yorkshire) weaned at 28 d of age were randomly assigned to receive 1 of 4 treatments (7 pigs/treatment): negative control, basal diet (NC), basal diet + 0.4% CAP (CAP), basal diet + 4 mg/kg DON (DON), and basal diet + 4 ppm DON + 0.4% CAP (DON + CAP). On d 15 and 30 after the initiation of treatment, blood samples were collected for the determination of blood profile. Piglets were monitored for 30 d to assess performance and then were slaughtered to obtain organs for the determination of the relative weight of organs. The results showed that dietary supplementation with DON decreased (P 0.05) on other relative weights of viscera, except the relative weight of the gallbladder, but the diamine oxidase activity in the liver decreased in DON-treated piglets (P 0.05) between the DON + CAP treatment and the other treatments. The DON treatment decreased the numbers of red blood cells and platelets, as well as the serum catalase concentrations, and decreased the serum concentrations of H2O2, maleic dialdehyde, and nitric oxide (P < 0.05). The numbers of platelets and thrombocytocrit, as well as the serum concentrations of catalase, were greater, whereas the maleic dialdehyde concentrations were decreased, in both the CAP and DON + CAP treatments compared with the other treatments (P < 0.05). Compared with the control treatment, DON decreased peripheral lymphocyte proliferation on d 15, whereas supplementation with CAP increased it on d 15 and 30 (P < 0

  6. Digital exchange of graphic arts material: the ultimate challenge

    Science.gov (United States)

    McDowell, David Q.

    1996-01-01

    The digital exchange of graphic arts material -- particularly advertising material for publications -- in an open standardized environment represents the ultimate challenge for electronic data exchange. To meet the needs of publication advertising, the graphic arts industry must be able to transmit advertisements in an open environment where there are many senders and many receivers of the material. The material being transmitted consists of combinations of pictorial material, text, and line art with these elements superimposed on top of each other and/or interrelated in complex ways. The business relationships established by the traditional workflow environment, the combination of aesthetic and technical requirements, and the large base of existing hardware and software play a major role in limiting the options available. Existing first- and second-generation standards are focused on the CEPS environment, which operates on and stores data as raster files. The revolution in personal computer hardware and software, and the acceptance of these tools by the graphic arts community, dictates that standards must also be created and implemented for this world of vector/raster-based systems. The requirements for digital distribution of advertising material for publications, the existing graphic arts standards base, and the anticipation of future standards developments in response to these needs are explored.

  7. Materials challenges in present and future wind energy

    DEFF Research Database (Denmark)

    Hayman, B.; Wedel-Heinen, J.; Brøndsted, Povl

    2008-01-01

    The main concept currently in use in wind energy involves horizontal-axis wind turbines with blades of fiber composite materials. This turbine concept is expected to remain as the major provider of wind power in the foreseeable future. However, turbine sizes are increasing, and installation...... offshore means that wind turbines will be exposed to more demanding environmental conditions. Many challenges are posed by the use of fiber composites in increasingly large blades and increasingly hostile environments. Among these are achieving adequate stiffness to prevent excessive blade deflection......, preventing buckling failure, ensuring adequate fatigue life under variable wind loading combined with gravitational loading, and minimizing the occurrence and consequences of production defects. A major challenge is to develop cost-effective ways to ensure that production defects do not cause unacceptable...

  8. Raw materials and energy: A challenge for polymer research

    Energy Technology Data Exchange (ETDEWEB)

    Weissermel, K.; Cherdron, H.

    1983-10-01

    The substantial rapid growth of synthetic polymers - plastics, man-made fibers, films, rubbers, and coatings - which continued unabated over many years, suffered a severe setback for the first time in 1973-1974 followed by another in 1980. A major cause of these reverses was the changed situation with respect to raw materials and energy. For industrial polymer research, in particular, this presents a fresh challenge with considerably changed priorities. The individual ways of meeting this challenge are highlighted and illustrated by examples: the search for alternative raw materials sources for monomers; the development of economic methods for the production and processing of polymers; the recycling of polymers; and finally the development of new raw material-saving and energy-saving technologies based on the use of polymers. In the future, the applications of polymers to new technologies such as communication- and information-systems or biotechnology will join the traditional uses. But the efforts required in research and development to achieve this demand wide-ranging interdisciplinary cooperation on an even greater scale than hitherto.

  9. Materials for ALFRED and ELFR – selection and challenges

    International Nuclear Information System (INIS)

    Materials are one of the challenging issues for all future GENIV reactors. Several EU funded projects, e.g. ELSY and LEADER, aimed to design Pb cooled nuclear systems including the European lead cooled reactor ELFR and the demonstrator ALFRED. The selection of the structural materials determines the design and the design has to consider the properties and the availability of the materials. Beside general requirements for material properties that are common for all fast reactor types specific issues arise from coolant compatibility. The high solubility of steel alloying elements in liquid Pb at reactor relevant temperatures is clearly detrimental. Therefore, all steels that are considered as structural materials have to be protected by dissolution barriers. The common barriers for all steels under consideration are oxide scales that form in situ during operation. However, increasing the temperature above 500 °C will result either in dissolution attack or in enhanced oxidation. For higher temperatures additional barriers like alumina forming surface alloys are discussed and investigated. Mechanical loads like creep stress and fretting will act on the steels. These mechanical loads will interact with the coolant and can increase the negative effects. For ALFRED austenitic steels (316 and 15-15Ti) are selected for most in core components. The 15-15Ti is the choice for the fuel cladding of ALFRED and the ferritic martensitic steel T91 was selected as fuel clad material of the ELFR. T91 is in both designs the material to be used for the heat exchanger. Surface alloying with alumina forming alloys is considered to assure material functionality at higher temperatures and is therefore selected for fuel cladding of the ELFR and the heat exchanger tubes. (author)

  10. An Injectable Hydrogel as Bone Graft Material with Added Antimicrobial Properties.

    Science.gov (United States)

    Tommasi, Giacomo; Perni, Stefano; Prokopovich, Polina

    2016-06-01

    Currently, the technique which provides the best chances for a successful bone graft, is the use of bone tissue from the same patient receiving it (autograft); the main limitations are the limited availability and the risks involved in removing living bone tissue, for example, explant site pain and morbidity. Allografts and xenografts may overcome these limitations; however, they increase the risk of rejection. For all these reasons the development of an artificial bone graft material is particularly important and hydrogels are a promising alternative for bone regeneration. Gels were prepared using 1,4-butanediol diacrylate as crosslinker and alpha tricalciumphosphate; ZnCl2 and SrCl2 were added to the aqueous phase. MTT results demonstrated that the addition of strontium had a beneficial effect on the osteoblast cells density on hydrogels, and zinc instead did not increase osteoblast proliferation. The amount of calcium produced by the osteoblast cells quantified through the Alizarin Red protocol revealed that both strontium and zinc positively influenced the formation of calcium; furthermore, their effect was synergistic. Rheology properties were used to mechanically characterize the hydrogels and especially the influence of crosslinker's concentration on them, showing the hydrogels presented had extremely good mechanical properties. Furthermore, the antimicrobial activity of strontium and zinc in the hydrogels against methicillin-resistant Staphylococcus aureus and Staphylococcus epidermidis was determined. PMID:27174392

  11. Antimicrobial nanocomposites based on natural modified materials: a review of carbons and clays.

    Science.gov (United States)

    Martynková, Grazyna Simha; Valásková, Marta

    2014-01-01

    The review is focused on the recent research and development of antimicrobial nanocomposites based on selected carbon nanomaterials and natural nanoclay minerals. The nanocomposites comprised of two or several components, where at least one presents antimicrobial properties, are discussed. Yet the most popular agent remains silver as nanoparticle or in ionic form. Second, broadly studied group, are organics as additives or polymeric matrices. Both carbons and clays in certain forms possess antimicrobial properties. A lot of interest is put on to research graphene oxide. The low-environmental impact technologies-based on sustainable biopolymers have been studied. Testing of antimicrobial properties of nanomaterials is performed most frequently on E. coli and S. aureus bacterias. PMID:24730289

  12. NASA Composite Materials Development: Lessons Learned and Future Challenges

    Science.gov (United States)

    Tenney, Darrel R.; Davis, John G., Jr.; Pipes, R. Byron; Johnston, Norman

    2009-01-01

    Composite materials have emerged as the materials of choice for increasing the performance and reducing the weight and cost of military, general aviation, and transport aircraft and space launch vehicles. Major advancements have been made in the ability to design, fabricate, and analyze large complex aerospace structures. The recent efforts by Boeing and Airbus to incorporate composite into primary load carrying structures of large commercial transports and to certify the airworthiness of these structures is evidence of the significant advancements made in understanding and use of these materials in real world aircraft. NASA has been engaged in research on composites since the late 1960 s and has worked to address many development issues with these materials in an effort to ensure safety, improve performance, and improve affordability of air travel for the public good. This research has ranged from synthesis of advanced resin chemistries to development of mathematical analyses tools to reliably predict the response of built-up structures under combined load conditions. The lessons learned from this research are highlighted with specific examples to illustrate the problems encountered and solutions to these problems. Examples include specific technologies related to environmental effects, processing science, fabrication technologies, nondestructive inspection, damage tolerance, micromechanics, structural mechanics, and residual life prediction. The current state of the technology is reviewed and key issues requiring additional research identified. Also, grand challenges to be solved for expanded use of composites in aero structures are identified.

  13. Novel functional materials from renewable lipids: Amphiphilic antimicrobial polymers and latent heat thermal energy storage

    Science.gov (United States)

    Floros, Michael Christopher

    Vegetable oils represent an ideal and renewable feedstock for the synthesis of a variety of functional materials. However, without financial incentive or unique applications motivating a switch, commercial products continue to be manufactured from petrochemical resources. Two different families of high value, functional materials synthesized from vegetable oils were studied. These materials demonstrate superior and unique performance to comparable petrochemical analogues currently on the market. In the first approach, 3 amphiphilic thermoplastic polytriazoles with differing lipophilic segment lengths were synthesized in a polymerization process without solvents or catalysts. Investigation of monomer structure influence on the resultant functional behaviour of these polymers found distinctive odd/even behaviour reliant on the number of carbon atoms in the monomers. Higher concentrations of triazole groups, due to shorter CH2 chains in the monomeric dialkynes, resulted in more brittle polymers, displaying higher tensile strengths but reduced elongation to break characteristics. These polymers had similar properties to commercial petroleum derived thermoplastics. One polymer demonstrated self-assembled surface microstructuring, and displayed hydrophobic properties. Antimicrobial efficacy of the polymers were tested by applying concentrated bacterial solutions to the surfaces, and near complete inhibition was demonstrated after 4 hours. Scanning electron microscope images of killed bacteria showed extensive membrane damage, consistent with the observed impact of other amphiphilic compounds in literature. These polytriazoles are suited for applications in medical devices and implants, where major concerns over antibiotic resistance are prevalent. In the second approach, a series of symmetric, saturated diester phase change materials (PCMs) were also synthesized with superior latent heat values compared to commercial petrochemical analogues. These diesters exhibit

  14. Modelling challenges for battery materials and electrical energy storage

    Science.gov (United States)

    Muller, Richard P.; Schultz, Peter A.

    2013-10-01

    Many vital requirements in world-wide energy production, from the electrification of transportation to better utilization of renewable energy production, depend on developing economical, reliable batteries with improved performance characteristics. Batteries reduce the need for gasoline and liquid hydrocarbons in an electrified transportation fleet, but need to be lighter, longer-lived and have higher energy densities, without sacrificing safety. Lighter and higher-capacity batteries make portable electronics more convenient. Less expensive electrical storage accelerates the introduction of renewable energy to electrical grids by buffering intermittent generation from solar or wind. Meeting these needs will probably require dramatic changes in the materials and chemistry used by batteries for electrical energy storage. New simulation capabilities, in both methods and computational resources, promise to fundamentally accelerate and advance the development of improved materials for electric energy storage. To fulfil this promise significant challenges remain, both in accurate simulations at various relevant length scales and in the integration of relevant information across multiple length scales. This focus section of Modelling and Simulation in Materials Science and Engineering surveys the challenges of modelling for energy storage, describes recent successes, identifies remaining challenges, considers various approaches to surmount these challenges and discusses the potential of these methods for future battery development. Zhang et al begin with atoms and electrons, with a review of first-principles studies of the lithiation of silicon electrodes, and then Fan et al examine the development and use of interatomic potentials to the study the mechanical properties of lithiated silicon in larger atomistic simulations. Marrocchelli et al study ionic conduction, an important aspect of lithium-ion battery performance, simulated by molecular dynamics. Emerging high

  15. Organic/inorganic hybrid materials: challenges for ab initio methodology.

    Science.gov (United States)

    Draxl, Claudia; Nabok, Dmitrii; Hannewald, Karsten

    2014-11-18

    CONSPECTUS: Organic/inorganic hybrid structures are most exciting since one can expect new properties that are absent in either of their building blocks. They open new perspectives toward the design and tailoring of materials with desired features and functions. Prerequisite for real progress is, however, the in-depth understanding of what happens on the atomic and electronic scale. In this respect, hybrid materials pose a challenge for electronic-structure theory. Methods that proved useful for describing one side may not be applicable for the other one, and they are likely to fail for the interfaces. In this Account, we address the question to what extent we can quantitatively describe hybrid materials and where we even miss a qualitative description. We note that we are dealing with extended systems and thus adopt a solid-state approach. Therefore, density-functional theory (DFT) and many-body perturbation theory (MBPT), the GW approach for charged and the Bethe-Salpeter equation for neutral excitations, are our methods of choice. We give a brief summary of the used methodology, focusing on those aspects where problems can be expected when materials of different character meet at an interface. These issues are then taken up when discussing hybrid materials. We argue when and why, for example, standard DFT may fall short when it comes to the electronic structure of organic/metal interfaces or where the framework of MBPT can or must take over. Selected examples of organic/inorganic interfaces, structural properties, electronic bands, optical excitation spectra, and charge-transport properties as obtained from DFT and MBPT highlight which properties can be reliably computed for such materials. The crucial role of van der Waals forces is shown for sexiphenyl films, where the subtle interplay between intermolecular and molecule-substrate interactions is decisive for growth and morphologies. With a PTCDA monolayer on metal surfaces we discuss the performance of DFT in

  16. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    K L Ramakumar

    2005-07-01

    Available analytical literature reveals that it is possible to identify a lot of procedures to carry out any determination using a plethora of analytical techniques. The fundamental analytical requirements for realizing the desired and acceptable information from a chemical analysis are representative nature of the sample, precision, accuracy, selectivity and sensitivity. These decide, to a larger extent, the selection of the most appropriate methodology in order to obtain chemical information from a system. A number of analytical methodologies are being used in the author’s laboratory for carrying out trace elemental analysis as a part of chemical quality control. Quite a good number of analytical challenges with specific reference to the characterization of high purity materials of relevance to nuclear technology were addressed and methodologies were developed for trace elemental analysis of both metallic and non-metallic constituents. A brief review of these analytical challenges and the analytical methodologies developed and also the future needs of analytical chemist are presented in this paper.

  17. A review of poly(lactic acid)-based materials for antimicrobial packaging.

    Science.gov (United States)

    Tawakkal, Intan S M A; Cran, Marlene J; Miltz, Joseph; Bigger, Stephen W

    2014-08-01

    Poly(lactic acid) (PLA) can be synthesized from renewable bio-derived monomers and, as such, it is an alternative to conventional petroleum-based polymers. Since PLA is a relatively new polymer, much effort has been directed toward its development in order to make it an acceptable and effective option to the more traditional petroleum-based polymers. Commercially, PLA has received considerable attention in food packaging applications with a focus on films and coatings that are suitable for short shelf life and ready-to-eat food products. The potential for PLA to be used in active packaging has also been recognized by a number of researchers. This review focuses on the use of PLA in antimicrobial systems for food packaging applications and explores the engineering characteristics and antimicrobial activity of PLA films incorporated and/or coated with antimicrobial agents. PMID:25039867

  18. MACRO DEFECT FREE MATERIALS; THE CHALLENGE OF MECHANOCHEMICAL ACTIVATION

    Directory of Open Access Journals (Sweden)

    MILAN DRÁBIK

    2012-12-01

    Full Text Available Macro-defect-free (MDF materials belong, according to Odler’s categorisation, to the type of materials where polymers may be successfully combined with cements and water to produce also the parameters of technological novelty and interests. A challenge, which has not been followed or indicated by now, is the option to intensify mixing of dry cement and polymer. The mechanochemical pre-reactions of dry MDF raw mixes consisting of Portland cement and polyphosphate, together with the model of atomic-level interpretations of the formed functional interfaces are proposed, experimentally tested and discussed in the present paper. The results ultimately show the activation of studied system due to the mechanochemical treatment, which consists in the initiation and measurable formation of Al(Fe–O–P cross-links already in the treated raw mixes. The mechanochemical activation of raw mixes in the high energy planetary mill for the duration of 5 minutes is proposed as the specific mixing and activation / pre-reaction step within the entire MDF synthesis procedure.

  19. Ab initio calculations for industrial materials engineering: successes and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Wimmer, Erich; Freeman, Clive; Christensen, Mikael; Wolf, Walter; Saxe, Paul [Materials Design, Inc., PO Box 2000, Angel Fire, NM 87710 (United States); Najafabadi, Reza; Young Jr, George A; Ballard, Jake D; Angeliu, Thomas M; Vollmer, James [Knolls Atomic Power Laboratory, PO Box 1072, Schenectady, NY 12301-1072 (United States); Chambers, James J; Niimi, Hiroaki; Shaw, Judy B, E-mail: ewimmer@materialsdesign.co [Advanced CMOS, Texas Instruments Incorporated, Dallas, TX 75243 (United States)

    2010-09-29

    Computational materials science based on ab initio calculations has become an important partner to experiment. This is demonstrated here for the effect of impurities and alloying elements on the strength of a Zr twist grain boundary, the dissociative adsorption and diffusion of iodine on a zirconium surface, the diffusion of oxygen atoms in a Ni twist grain boundary and in bulk Ni, and the dependence of the work function of a TiN-HfO{sub 2} junction on the replacement of N by O atoms. In all of these cases, computations provide atomic-scale understanding as well as quantitative materials property data of value to industrial research and development. There are two key challenges in applying ab initio calculations, namely a higher accuracy in the electronic energy and the efficient exploration of large parts of the configurational space. While progress in these areas is fueled by advances in computer hardware, innovative theoretical concepts combined with systematic large-scale computations will be needed to realize the full potential of ab initio calculations for industrial applications.

  20. Ab initio calculations for industrial materials engineering: successes and challenges

    International Nuclear Information System (INIS)

    Computational materials science based on ab initio calculations has become an important partner to experiment. This is demonstrated here for the effect of impurities and alloying elements on the strength of a Zr twist grain boundary, the dissociative adsorption and diffusion of iodine on a zirconium surface, the diffusion of oxygen atoms in a Ni twist grain boundary and in bulk Ni, and the dependence of the work function of a TiN-HfO2 junction on the replacement of N by O atoms. In all of these cases, computations provide atomic-scale understanding as well as quantitative materials property data of value to industrial research and development. There are two key challenges in applying ab initio calculations, namely a higher accuracy in the electronic energy and the efficient exploration of large parts of the configurational space. While progress in these areas is fueled by advances in computer hardware, innovative theoretical concepts combined with systematic large-scale computations will be needed to realize the full potential of ab initio calculations for industrial applications.

  1. The use of polyurethane foam as an antimicrobial dressing material in hand surgery

    Directory of Open Access Journals (Sweden)

    Nebil Yesiloglu

    2015-12-01

    Full Text Available Polyurethane foam is generally used in negative pressure-assisted wound closure therapy. It provides an antimicrobial environment around the wound, while reducing the rate of skin maceration. The authors used polyurethane foam in routine hand dressings after hand surgery operations that were performed for both congenital and acquired purposes. [Hand Microsurg 2015; 4(3.000: 91-92

  2. Material Challenges For Plasma Facing Components in Future Fusion Reactors

    International Nuclear Information System (INIS)

    Increasing attention is directed towards thermonuclear fusion as a possible future energy source. Major advantages of this energy conversion technology are the almost inexhaustible resources and the option to produce energy without CO2-emissions. However, in the most advanced field of magnetic plasma confinement a number of technological challenges have to be met. In particular high-temperature resistant and plasma compatible materials have to be developed and qualified which are able to withstand the extreme environments in a commercial thermonuclear power reactor. The plasma facing materials (PFMs) and components (PFCs) in such fusion devices, i.e. the first wall (FW), the limiters and the divertor, are strongly affected by the plasma wall interaction processes and the applied intense thermal loads during plasma operation. On the one hand, these mechanisms have a strong influence on the plasma performance; on the other hand, they have major impact on the lifetime of the plasma facing armour. In present-day and next step devices the resulting thermal steady state heat loads to the first wall remain below 1 MWm-2; the limiters and the divertor are expected to be exposed to power densities being at least one order of magnitude above the FW-level, i.e. up to 20 MWm-2 for next step tokamaks such as ITER or DEMO. These requirements are responsible for high demands on the selection of qualified PFMs and heat sink materials as well as reliable fabrication processes for actively cooled plasma facing components. The technical solutions which are considered today are mainly based on the PFMs beryllium, carbon or tungsten joined to copper alloys or stainless steel heat sinks. In addition to the above mentioned quasi-stationary heat loads, short transient thermal pulses with deposited energy densities up to several tens of MJm-2 are a serious concern for next step tokamak devices. The most frequent events are so-called Edge Localized Modes (type I ELMs) and plasma disruptions

  3. Antimicrobial Drugs in Fighting against Antimicrobial Resistance

    Directory of Open Access Journals (Sweden)

    Guyue eCheng

    2016-04-01

    Full Text Available The outbreak of antimicrobial resistance, together with the lack of newly developed antimicrobial drugs, represents an alarming signal for both human and animal healthcare worldwide. Selection of rational dosage regimens for traditional antimicrobial drugs based on pharmacokinetic/pharmacodynamic principles as well as development of novel antimicrobials targeting new bacterial targets or resistance mechanisms are key approaches in tackling AMR. In addition to the cellular level resistance (i.e., mutation and horizontal gene transfer of resistance determinants, the community level resistance (i.e., bilofilms and persisters is also an issue causing antimicrobial therapy difficulties. Therefore, anti-resistance and antibiofilm strategies have currently become research hotspot to combat antimicrobial resistance. Although metallic nanoparticles can both kill bacteria and inhibit biofilm formation, the toxicity is still a big challenge for their clinical applications. In conclusion, rational use of the existing antimicrobials and combinational use of new strategies fighting against antimicrobial resistance are powerful warranties to preserve potent antimicrobial drugs for both humans and animals.

  4. Materials control and accountability challenges associated with plutonium inventories

    International Nuclear Information System (INIS)

    There are currently many initiatives underway within the Department of Energy (DOE) to safely and securely manage large plutonium inventories arising from weapons dismantlement, changing missions and facility operations. Plutonium inventory information is increasingly accessible to the public as a result of the secretary of energy's openness initiative. As a result, knowledge of these inventories and levels to which the department has accounted for and controlled these inventories, will be under increased scrutiny from a variety of interest groups. The quality of this accountability data and what this data means will greatly influence the public's perception of how the US is protecting its plutonium inventories. In addition, the department's safeguards program provides an essential basis for the application of International Atomic Energy Agency (IAEA) safeguards that, in addition to possibly other international control regimes, will be in place over a large portion of these future inventories. The capability and functionality of the department's nuclear safeguards program will be important contributors to the success of US programs for the responsible stewardship of these vast plutonium inventories. This paper discusses some of the challenges, in terms of specific issues relating to one part of the department's safeguards program--materials control and accountability (MC and A)--to meet the growing domestic and international requirements and expectations associated with these plutonium inventories

  5. Opportunities and challenges for materials innovation in nuclear energy

    International Nuclear Information System (INIS)

    Materials performance is central to the satisfactory operation of current and future nuclear energy systems. For example, the remarkable improvement in the operation and reliability of Generation-II light water reactors (LWRs) over the past 25 years has been largely associated with improvements in steam generator materials, fuel cladding technology (composition and fabrication), and improved understanding of water chemistry impacts on corrosion and deposition. Future fission and proposed fusion energy systems will be increasingly dependent on advanced structural materials to reliably deliver high performance with favorable safety attributes and acceptable economic cost. In many cases, the proposed operating temperatures are significantly higher than the experience base for light water reactors. This motivates development of structural materials with improved high temperature strength for prolonged operating periods and engineered corrosion resistance for the candidate coolants and other materials in the system. The high radiation fluxes in future nuclear energy systems will require the structural materials to have superior radiation resistance compared to currently available materials. The material performance demands are particularly challenging for the fuel cladding and wrapper of next-generation sodium-cooled fast reactors, where simultaneous resistance to high temperature thermal creep and radiation-induced property degradation up to doses of ∼100-150 dpa is required. Several strategies can be utilized to develop structural materials with simultaneous high radiation resistance, high strength, good toughness and corrosion resistance, and moderate fabrication cost. There are three general approaches for designing radiation resistance: Nano-scale precipitates or interfaces to produce high point defect sink strength (e.g., oxide dispersion strengthened (ODS) and next-generation ferritic/martensitic steels with high particle densities); purposeful utilization of

  6. Effect of Storage in Distilled Water for Three Months on the Antimicrobial Properties of Poly(methyl methacrylate Denture Base Material Doped with Inorganic Filler

    Directory of Open Access Journals (Sweden)

    Grzegorz Chladek

    2016-04-01

    Full Text Available The colonization of poly(methyl methacrylate (PMMA denture base materials by pathogenic microorganisms is a major problem associated with the use of prostheses, and the incorporation of antimicrobial fillers is a method of improving the antimicrobial properties of these materials. Numerous studies have demonstrated the initial in vitro antimicrobial effectiveness of this type of material; however, reports demonstrating the stability of these fillers over longer periods are not available. In this study, silver sodium hydrogen zirconium phosphate was introduced into the powder component of a PMMA denture base material at concentrations of 0.25%, 0.5%, 1%, 2%, 4%, and 8% (w/w. The survival rates of the gram-positive bacterium Staphylococcus aureus, gram-negative bacterium Escherichia coli and yeast-type fungus Candida albicans were established after fungal or bacterial suspensions were incubated with samples that had been previously stored in distilled water. Storage over a three-month period led to the progressive reduction of the initial antimicrobial properties. The results of this study suggest that additional microbiological tests should be conducted for materials that are treated with antimicrobial fillers and intended for long-term use. Future long-term studies of the migration of silver ions from the polymer matrix and the influence of different media on this ion emission are required.

  7. Antimicrobial and antioxidant surface modification toward a new silk-fibroin (SF)-L-Cysteine material for skin disease management

    Science.gov (United States)

    Nogueira, Frederico; Granadeiro, Luíza; Mouro, Claudia; Gouveia, Isabel C.

    2016-02-01

    A novel dressing material - silk fibroin fabric (SF)-L-Cysteine (L-Cys) - is here developed to be used as standard treatment for atopic dermatitis (AD), which combines comfort, thermic, and tensile strength properties of silk materials with antioxidant and antimicrobial effects of L-Cys. A careful understanding about the linking strategies is needed in order not to compromise the bioavailability of L-Cys and deplenish its bioactivity. Durability was also addressed through washing cycles and compared with hospital requirements, according to international Standard EN ISO 105-C06:2010. The present research also analyze the interactions between Staphylococcus aureus and SF-L-Cys under simulating conditions of AD and demonstrated the effectiveness of a double covalent grafting, with the importance of SF tyrosine (Tyr) covalent linkage with L-Cys (SF-g-L-Cys/Tyr-g-L-Cys) even after several washing cycles, twenty five, whereas for a disposable application a single covalent mechanism of grafting L-Cys proved to be sufficient (SF-g-L-Cys). Results showed effective antimicrobial activities exhibiting higher inhibition ratios of 98.65% for SF-g-L-Cys after 5 washing cycles, whereas 97.55% for SF-g-L-Cys/Tyr-g-L-Cys after 25 washing cycles, both at pH 9.5 grafting strategy. Furthermore, it is also reported a non-protumoral effect of L-Cys. A new advance is herein achieved at the world of medical antimicrobial textiles tailored to address wound moisture environment and exudate self-cleaning, which may open novel applications as complementary therapy for AD disease.

  8. Characterization and antimicrobial performance of nano silver coatings on leather materials

    OpenAIRE

    Lkhagvajav, N.; Koizhaiganova, M.; Yasa, I.; Çelik, E.; Ö. Sari

    2015-01-01

    In this study, the characterization and the antimicrobial properties of nano silver (nAg) coating on leather were investigated. For this purpose, turbidity, viscosity and pH of nAg solutions prepared by the sol-gel method were measured. The formation of films from these solutions was characterized according to temperature by Differential Thermal Analysis-Thermogravimetry (DTA-TG) equipment. The surface morphology of treated leathers was observed using Scanning Electron Microscopy (SEM). The a...

  9. Covalent and non-covalent strategies for surface modification of different textile materials with antimicrobial properties

    OpenAIRE

    Nogueira, Frederico; Pedrosa, Marta; Teixeira, P.; Piskin, Erhan; Gouveia, Isabel

    2012-01-01

    New advances have been released in textile industry. Contributions at the level of textile fiber chains engineering has allowed modification of their structure, production of smart polymers responding to changes in environment, and attachment or entrapment of cells and bioactive molecules. Likewise, our society high demand of hygienic patterns, has raised the intensive research and development of antimicrobial textiles. Applications are being extended to underwear, sportswear, hom...

  10. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... issue of antimicrobial resistance is that the subject material appears abstract and is complex. This video was ... can develop and spread. All FDA CVM produced material may be copied, reproduced, and distributed as long ...

  11. Forging the Solution to the Energy Challenge: The Role of Materials Science and Materials Scientists

    Science.gov (United States)

    Wadsworth, Jeffrey

    2010-05-01

    The energy challenge is central to the most important strategic problems facing the United States and the world. It is increasingly clear that even large-scale deployments of the best technologies available today cannot meet the rising energy demands of a growing world population. Achieving a secure and sustainable energy future will require full utilization of, and substantial improvements in, a comprehensive portfolio of energy systems and technologies. This goal is complicated by several factors. First, energy strategies are inextricably linked to national security and health issues. Second, in developing and deploying energy technologies, it is vital to consider not only environmental issues, such as global climate change, but also economic considerations, which strongly influence both public and political views on energy policy. Third, a significant and sustained effort in basic and applied research and development (R&D) will be required to deliver the innovations needed to ensure a desirable energy future. Innovations in materials science and engineering are especially needed to overcome the limits of essentially all energy technologies. A wealth of historical evidence demonstrates that such innovations are also the key to economic prosperity. From the development of the earliest cities around flint-trading centers, to the Industrial Revolution, to today’s silicon-based global economy, the advantage goes to those who lead in exploiting materials. I view our challenge by considering the rate of innovation and the transition of discovery to the marketplace as the relationship among R&D investment, a skilled and talented workforce, business innovations, and the activities of competitors. Most disturbing in analyzing this relationship is the need for trained workers in science, technology, engineering, and mathematics (STEM). To develop the STEM workforce needed for innovation, we need sustainable, positive change in STEM education at all levels from preschool

  12. Durable innovative solar optical materials: the international challenge

    Energy Technology Data Exchange (ETDEWEB)

    Lampert, C.M.

    1982-01-01

    A variety of optical coatings are discussed in the context of solar energy utilization. Well known coatings such as heat mirrors, selective absorbers, and reflective films are covered briefly. Emphasis is placed on the materials limitations and design choices for various lesser known optical coatings and materials. Physical and optical properties are detailed for protective antireflection films, fluorescent concentrator materials, holographic films, cold mirrors, radiative cooling surfaces, and optical switching films including electrochromic, thermochromic, photochromic, and liquid crystal types. For many of these materials research is only now being considered, and various design and durability issues must be addressed.

  13. Advantages and challenges of dissimilar materials in automotive lightweight construction

    Science.gov (United States)

    Weberpals, Jan-Philipp; Schmidt, Philipp A.; Böhm, Daniel; Müller, Steffen

    2015-03-01

    The core of future automotive lightweight materials is the joining technology of various material mixes. The type of joining will be essential, particularly in electrified propulsion systems, especially as an improved electrical energy transmission leads to a higher total efficiency of the vehicle. The most evident parts to start the optimization process are the traction battery, the electrical performance modules and the engines. Consequently aluminum plays a very central role for lightweight construction applications. However, the physical-technical requirements of components often require the combination with other materials. Thus the joining of mixed material connections is an essential key technology for many of the current developments, for example in the areas E-Mobility, solar energy and lightweight construction. Due to these advantages mixed material joints are already established in the automotive industry and laser beam remote welding is now a focus technology for mixed material connections. The secret of the laser welding process with mixed materials lies within the different areas of the melting phase diagram depending on the mixing ratio and the cooling down rate. According to that areas with unwanted, prim, intermetallic phases arise in the fusion zone. Therefore, laser welding of mixed material connections can currently only be used with additional filler in the automotive industry.

  14. The challenge of developing structural materials for fusion power systems

    International Nuclear Information System (INIS)

    Nuclear fusion can be one of the most attractive sources of energy from the viewpoint of safety and minimal environmental impact. Central in the goal of designing a safe, environmentally benign, and economically competitive fusion power system is the requirement for high performance, low activation materials. The general performance requirements for such materials have been defined and it is clear that materials developed for other applications (e.g. aerospace, nuclear fission, fossil energy systems) will not fully meet the needs of fusion. Advanced materials, with composition and microstructure tailored to yield properties that will satisfy the specific requirements of fusion must be developed. The international fusion programs have made significant progress towards this goal. Compositional requirements for low activation lead to a focus of development efforts on silicon carbide composites, vanadium alloys, and advanced martensitic steels as candidate structural material systems. Control of impurities will be critically important in actually achieving low activation but this appears possible. Neutron irradiation produces significant changes in the mechanical and physical properties of each of these material systems raising feasibility questions and design limitations. A focus of the research and development effort is to understand these effects, and through the development of specific compositions and microstructures, produce materials with improved and adequate performance. Other areas of research that are synergistic with the development of radiation resistant materials include fabrication, joining technology, chemical compatibility with coolants and tritium breeders and specific questions relating to the unique characteristics of a given material (e.g. coatings to reduce gas permeation in SiC composites) or design concept (e.g. electrical insulator coatings for liquid metal concepts). (orig.)

  15. Photonic band gap materials: Technology, applications and challenges

    International Nuclear Information System (INIS)

    Last century has been the age of Artificial Materials. One material that stands out in this regard is the semiconductor. The revolution in electronic industry in the 20th century was made possible by the ability of semiconductors to microscopically manipulate the flow of electrons. Further advancement in the field made scientists suggest that the new millennium will be the age of photonics in which artificial materials will be synthesized to microscopically manipulate the flow of light. One of these will be Photonic Band Gap material (PBG). PBG are periodic dielectric structures that forbid propagation of electromagnetic waves in a certain frequency range. They are able to engineer most fundamental properties of electromagnetic waves such as the laws of refraction, diffraction, and emission of light from atoms. Such PBG material not only opens up variety of possible applications (in lasers, antennas, millimeter wave devices, efficient solar cells photo-catalytic processes, integrated optical communication etc.) but also give rise to new physics (cavity electrodynamics, localization, disorder, photon-number-state squeezing). Unlike electronic micro-cavity, optical waveguides in a PBG microchip can simultaneously conduct hundreds of wavelength channels of information in a three dimensional circuit path. In this article we have discussed some aspects of PBG materials and their unusual properties, which provided a foundation for novel practical applications ranging from clinical medicine to information technology. (author)

  16. Progress in materials for microelectronics and further challenges

    International Nuclear Information System (INIS)

    Development of materials and technologies for microelectronics is required by the needs of the constantly increasing level of integration of microelectronics circuits. Increase of the integration level compels down scaling of all the dimensions of devices, which in its turn requires very thin layers with exceptional quality due to rather high electric fields at working conditions. First, technological improvements are adopted aimed at fabrication of materials with uniform quality, geometrical flatness and extremely low density of intentionally introduced defects. Second, new fabrication methods are developed providing materials with much better quality. Third, new materials showing better properties than the standard (conventional) ones are obtained and developed further. Decreasing the dimensions of the layers changes the nature of the physical phenomena involved in the functioning of devices. Quantum mechanical mechanisms are more and more important in the description of the properties of the materials and devices on the nano scale. The question arises where is the limit of the possibilities of the materials and technologies for nano scale electronics. (Author)

  17. Challenges and Benefits of Utilizing Carbon Nanofilaments in Cementitious Materials

    Directory of Open Access Journals (Sweden)

    Ardavan Yazdanbakhsh

    2012-01-01

    Full Text Available Carbon nanofibers/tubes (CNF/Ts are very strong and stiff and as a result, are expected to be capable of enhancing the mechanical properties of cementitious materials significantly. Yet there are practical issues concerning the utilization of CNF/Ts in cementitious materials. This study summarizes some of the past efforts made by different investigators for utilizing carbon nanofilaments in cementitious materials and also reports recent experimental research performed by the authors on the mechanical properties of CNF-reinforced hardened cement paste. The major difficulties concerning the utilization of CNF/Ts in cementitious materials are introduced and discussed. Most of these difficulties are related to the poor dispersibility of CNF/Ts. However, the findings from the research presented in this work indicate that, despite these difficulties, carbon nanofilaments can significantly improve the mechanical properties of cementitious materials. The results show that CNFs, even when poorly dispersed within the cementitious matrix, can remarkably increase the flexural strength and cracking resistance of concrete subjected to drying conditions.

  18. Turning Waste into Value: Nanosized Natural Plant Materials of Solanum incanum L. and Pterocarpus erinaceus Poir with Promising Antimicrobial Activities.

    Science.gov (United States)

    Griffin, Sharoon; Tittikpina, Nassifatou Koko; Al-Marby, Adel; Alkhayer, Reem; Denezhkin, Polina; Witek, Karolina; Gbogbo, Koffi Apeti; Batawila, Komlan; Duval, Raphaël Emmanuel; Nasim, Muhammad Jawad; Awadh-Ali, Nasser A; Kirsch, Gilbert; Chaimbault, Patrick; Schäfer, Karl-Herbert; Keck, Cornelia M; Handzlik, Jadwiga; Jacob, Claus

    2016-01-01

    Numerous plants are known to exhibit considerable biological activities in the fields of medicine and agriculture, yet access to their active ingredients is often complicated, cumbersome and expensive. As a consequence, many plants harbouring potential drugs or green phyto-protectants go largely unnoticed, especially in poorer countries which, at the same time, are in desperate need of antimicrobial agents. As in the case of plants such as the Jericho tomato, Solanum incanum, and the common African tree Pterocarpus erinaceus, nanosizing of original plant materials may provide an interesting alternative to extensive extraction and isolation procedures. Indeed, it is straightforward to obtain considerable amounts of such common, often weed-like plants, and to mill the dried material to more or less uniform particles of microscopic and nanoscopic size. These particles exhibit activity against Steinernema feltiae or Escherichia coli, which is comparable to the ones seen for processed extracts of the same, respective plants. As S. feltiae is used as a model nematode indicative of possible phyto-protective uses in the agricultural arena, these findings also showcase the potential of nanosizing of crude "waste" plant materials for specific practical applications, especially-but not exclusively-in developing countries lacking a more sophisticated industrial infrastructure. PMID:27104554

  19. A review on the application of inorganic nano-structured materials in the modification of textiles: focus on anti-microbial properties.

    Science.gov (United States)

    Dastjerdi, Roya; Montazer, Majid

    2010-08-01

    Textiles can provide a suitable substrate to grow micro-organisms especially at appropriate humidity and temperature in contact to human body. Recently, increasing public concern about hygiene has been driving many investigations for anti-microbial modification of textiles. However, using many anti-microbial agents has been avoided because of their possible harmful or toxic effects. Application of inorganic nano-particles and their nano-composites would be a good alternative. This review paper has focused on the properties and applications of inorganic nano-structured materials with good anti-microbial activity potential for textile modification. The discussed nano-structured anti-microbial agents include TiO(2) nano-particles, metallic and non-metallic TiO(2) nano-composites, titania nanotubes (TNTs), silver nano-particles, silver-based nano-structured materials, gold nano-particles, zinc oxide nano-particles and nano-rods, copper nano-particles, carbon nanotubes (CNTs), nano-clay and its modified forms, gallium, liposomes loaded nano-particles, metallic and inorganic dendrimers nano-composite, nano-capsules and cyclodextrins containing nano-particles. This review is also concerned with the application methods for the modification of textiles using nano-structured materials. PMID:20417070

  20. Materials Challenges for High Performance Magnetocaloric Refrigeration Devices

    DEFF Research Database (Denmark)

    Smith, Anders; Bahl, Christian; Bjørk, Rasmus;

    2012-01-01

    Magnetocaloric materials with a Curie temperature near room temperature have attracted signifi cant interest for some time due to their possible application for high-effi ciency refrigeration devices. This review focuses on a number of key issues of relevance for the characterization, performance...

  1. PROFESSIONAL CHALLENGES CONCERNING THE CALCULATION AND USE OF MATERIALITY

    OpenAIRE

    Daniel Botez

    2013-01-01

    Significance is an essential reference in the judgments of the economic environment. It talks about significant influence, meaningful, significant risk, significant accounting policies, and the like. In accounting and auditing is used the term "materiality" when the submit financial information, to evaluate the risk or partial information or investigating events using statistical sampling technique. Starting from the premise that the conceptual and practical approach of the threshold of signi...

  2. Sustainable hydrogen - A challenge for materials science and equipment design

    International Nuclear Information System (INIS)

    Full text: Hydrogen is the ideal fuel, considering its fully non-polluting by-products. Still, in discussions on 'sustainable hydrogen', there must be considered all the steps implied in hydrogen production, storage and use and the overall energy balance represents the real starting point of evaluating the sustainability. So far, hydrogen production is related to rather energy-consuming processes; extended research is devoted to develop high efficiency processes, but the industrial hydrogen production makes use of either large electrical or thermal energy amounts. Hydrogen production via water photolysis represents, consequently a viable alternative although many steps have to be elaborated to reached the industrial scale of these processes. Hydrogen storing represents another problem that affects its application; a safe storage way, in metal hydrides, is still under intensive research all over the world. The group of the Centre of Product Design for Sustainable Development is engaged in research for developing a laboratory photolyser, able to produce hydrogen and to offer an efficient storage alternative. The photolyser is a photo-electrochemical cell, and the efficiency of the photolysis process depends on several factors: - the photo-electrodes: thin films of wide band gap semiconductors with tailored properties; - the aqueous environment, with effect on the electrode materials properties and stability; - the external bias; - the cell design. The paper focuses mainly on the photo-electrode materials that were tested. The influence of the composition, crystalline and defect structure, of the morphology and of the interfaces on the photolysis process are reviewed. The effect of the pH in the aqueous media is discussed along with the stability of the materials and the reversibility of the adsorption/desorption processes. The design criteria that must be fulfilled in developing the photolyser are also discussed. (authors)

  3. Meeting the challenges related to material issues in chemical industries

    Indian Academy of Sciences (India)

    Baldev Raj; U Kamachi Mudali; T Jayakumar; K V Kasiviswanathn; K Natarajan

    2000-12-01

    Reliable performance and profitability are two important requirements for any chemical industry. In order to achieve high level of reliability and excellent performance, several issues related to design, materials selection, fabrication, quality assurance, transport, storage, inputs from condition monitoring, failure analysis etc. have to be adequately addressed and implemented. Technology related to nondestructive testing and monitoring of the plant is also essential for precise identification of defect sites and to take appropriate remedial decision regarding repair, replacement or modification of process conditions. The interdisciplinary holistic approach enhances the life of critical engineering components in chemical plants. Further, understanding the failure modes of the components through the analysis of failed components throws light on the choice of appropriate preventive measures to be taken well in advance, to have a control over the overall health of the plant. The failure analysis also leads to better design modification and condition monitoring methodologies, for the next generation components and plants. At the Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, a unique combination of the expertise in design, materials selection, fabrication, NDT development, condition monitoring, life prediction and failure analysis exists to obtain desired results for achieving high levels of reliability and performance assessment of critical engineering components in chemical industries. Case studies related to design, materials selection and fabrication aspects of critical components in nuclear fuel reprocessing plants, NDT development and condition monitoring of various components of nuclear power plants, and important failure investigations on critical engineering components in chemical and allied industries are discussed in this paper. Future directions are identified and planned approaches are briefly described.

  4. Material challenges in ethylene pyrolysis furnace heater service

    Energy Technology Data Exchange (ETDEWEB)

    Ibarra, S.

    1980-02-01

    Operating temperatures of pyrolysis furnaces are sometimes in excess of 2000/sup 0/F (1100/sup 0/C). These temperatures are very detrimental to the life of the typical HK-40 furnace tubes which normally have a three to five year life in the hot section of these furnaces. Short life is attributed to rapid carburization of ID surfaces which subjects tubes to higher than normal stresses and results in creep cracking of furnace tubes. As an aid to understanding the materials problems the ethylene process will be presented, along with data on the carburization of furnace tubes.

  5. PAT challenges routine techniques on defect spectroscopy in material science

    International Nuclear Information System (INIS)

    Atomic or Point Defects are the most simple defects in solids. Due to the small size their direct observation by the routine techniques is not possible. A single type of defects (thermal defect) was observed in the quenching process. Using the Arrhenius method and threshold method we recommended the accurate both method of treatments. The calculated values for formation enthalpies and self-diffusion using positron lifetime and Doppler broadening in a good agreement in (A356.0) and (A413.1). Specifically it is show how PAT detect defect concentrations, (formation- migration) enthalpies and grain size for the material under investigation. Most of the these data are reported

  6. Materials for ALFRED and ELFR selection and challenges

    International Nuclear Information System (INIS)

    • Solubility, oxygen potential, dissolution and oxidation kinetics are key parameters for material compatibility; • Temperature limits for corrosion (dissolution) of steels in Pb/PbBi: 316 type steels: Tlimit limit3SiC2 good corrosion properties – erosion resistance to be tested; • Ta severe oxidation – hardening – not suitable in oxygen containing Pb; • Direct contact with Pb reduces mechanical properties – protective scales: - creep rupture strength; - LME (liquid metal embrittlement) at low temperature (2O3 scales forming on top increase heat transfer capability and reduce corrosion attack: • mitigates reduction in creep rupture strength; • reduces amount oxygen to be added – oxygen control easier. → We still have some work before Materials for ALFRED or ELFR are qualified; → E.g. verification of upper limit for austenitic steels; → Reliable production of surface barriers (GESA); → Proof of long term and irradiation stability → Fretting, Erosion, LM degradation.....?; → LM chemistry – oxygen supply and control

  7. The challenge for innovation in direct restorative materials

    DEFF Research Database (Denmark)

    Bayne, S; Petersen, P E; Piper, D;

    2013-01-01

    Convention). Dental caries is omnipresent around the globe, affecting 60% to 90% of school children and most adults, and producing discomfort that affects quality of life. Dental amalgam is frequently used to treat carious lesions and its use releases mercury into the environment. The best way to avoid the...... use of dental amalgam is to emphasize caries prevention. Alternatives to amalgam are suitable in some applications, but no replacement for amalgam has been found for large posterior restorations. For any restorative material, safety and environmental impacts are part of clinical risk assessment....... Safety is freedom from unacceptable risks. Risk is a combination of probability of exposure and severity of harm. Best management practices are crucial to manage dental amalgam, but these impose additional that are disproportionately more for developing countries. The Minamata Convention seeks a phase...

  8. Overview of DOE-NE Structural Materials Research, Materials Challenges and Operating Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Maloy, Stuart A. [Los Alamos National Laboratory; Busby, Jeremy T. [ORNL

    2012-06-12

    This presentation summarized materials conditions for application of nanomaterials to reactor components. Material performance is essential to reactor performance, economics, and safety. A modern reactor design utilizes many different materials and material systems to achieve safe and reliable performance. Material performance in these harsh environments is very complex and many different forms of degradation may occur (often together in synergistic fashions). New materials science techniques may also help understand degradation modes and develop new manufacturing and fabrication techniques.

  9. Vegetable-Oil-Based Hyperbranched Polyester-Styrene Copolymer Containing Silver Nanoparticle as Antimicrobial and Corrosion-Resistant Coating Materials

    Directory of Open Access Journals (Sweden)

    Manawwer Alam

    2013-01-01

    Full Text Available Pongamia oil (PO was converted to Pongamia oil hydroxyl (POH via epoxidation process. The esterification of POH with linolenic acid was carried out to form hyperbranched polyester (HBPE, and further styrenation was performed at the conjugated double bond in the chain of linolenic acid. After styrenation, silver nanoparticle was added in different weight percentages (0.1–0.4 wt%. The structural elucidation of POH, HBPE, and HBPE-St was carried out by FT-IR, 1H-NMR, and 13C-NMR spectroscopic techniques. Physicochemical and physicomechanical analyses were performed by standard method. Thermal behavior of the HBPE-St was analyzed by using thermogravimetric analysis (TGA and differential scanning calorimetry (DSC. The coatings of HBPE-St were prepared on mild steel strips. The anticorrosive behavior of HBPE-St resin-based coatings in acid, saline, and tap water was evaluated, and the molecular weight of HBPE-St was determined by gel permeation chromatography (GPC. The antibacterial activities of the HBPE-St copolymers were tested in vitro against bacteria and fungi by disc diffusion method. The HBPE-St copolymers exhibited good antibacterial activities and can be used as antimicrobial and corrosion-resistant coating materials.

  10. Antimicrobial Pesticides

    Science.gov (United States)

    ... US EPA US Environmental Protection Agency Search Search Pesticides Share Facebook Twitter Google+ Pinterest Contact Us You are here: EPA Home » Pesticides » Antimicrobial Pesticides Antimicrobial Pesticides News and Highlights Disinfection Hierarchy Workshop - October 7 ...

  11. Novel silver containing antimicrobial coatings for implant materials. new applications of Ag(I) coordination networks

    OpenAIRE

    Vig Slenters, Tünde

    2009-01-01

    Modern medicine continuously develops new artificial short-term or permanent devices to assist in the performance of physiological functions. Implantation of medical devices represents one of the most important risk factors of all nosocomial infections, when implant materials become infected due to bacterial adhesion and subsequent formation of bio films. The latter are impossible to treat with antibiotics and represent a dramatic complication for the patient, leading to implant replacement, ...

  12. Metal-Organic and Organic TADF-Materials: Status, Challenges and Characterization.

    Science.gov (United States)

    Bergmann, Larissa; Zink, Daniel M; Bräse, Stefan; Baumann, Thomas; Volz, Daniel

    2016-06-01

    This section covers both metal-organic and organic materials that feature thermally activated delayed fluorescence (TADF). Such materials are especially useful for organic light-emitting diodes (OLEDs), a technology that was introduced in commercial displays only recently. We compare both material classes to show commonalities and differences, highlighting current issues and challenges. Advanced spectroscopic techniques as valuable tools to develop solutions to those issues are introduced. Finally, we provide an outlook over the field and highlight future trends. PMID:27573262

  13. Materials Development in the Colombian Context: Some Considerations About Its Benefits and Challenges

    Directory of Open Access Journals (Sweden)

    Bertha Ramos Holguín

    2014-10-01

    Full Text Available Materials development is a field of study which has recently acquired significant importance in the Colombian context due to the fact that teachers, as materials developers, consider materials development as an area of knowledge that helps them to improve their teaching practices. However, the rationale, the gains as well as the challenges that drive materials designers have not been explored enough in Colombia. This article aims to provide some general considerations about the benefits teachers, as material developers, will obtain and some of the shortcomings which may emerge along this process. Finally, the authors discuss some implications for teachers, students, and teacher education programs.

  14. Antimicrobial Stewardship Programs: Role in Optimizing Infectious Disease Outcomes

    OpenAIRE

    Kubin, Christine J.

    2008-01-01

    Given increasing trends in antimicrobial resistance and the resulting limited treatment options, the treatment of hospital-acquired infections poses a significant challenge to healthcare providers. Optimization and conservation of current antimicrobials are necessary. Antimicrobial stewardship programs aim to optimize the use of antimicrobial agents through a multidisciplinary effort utilizing different strategies (prospective audit and feedback, formulary restriction and preauthorization, ed...

  15. RIMS International Conference : Mathematical Challenges in a New Phase of Materials Science

    CERN Document Server

    Kotani, Motoko

    2016-01-01

    This volume comprises eight papers delivered at the RIMS International Conference "Mathematical Challenges in a New Phase of Materials Science", Kyoto, August 4–8, 2014. The contributions address subjects in defect dynamics, negatively curved carbon crystal, topological analysis of di-block copolymers, persistence modules, and fracture dynamics. These papers highlight the strong interaction between mathematics and materials science and also reflect the activity of WPI-AIMR at Tohoku University, in which collaborations between mathematicians and experimentalists are actively ongoing.

  16. Challenging Ideological Exclusion of Curriculum Material: Rights of Students and Parents.

    Science.gov (United States)

    Stern, Nat

    1979-01-01

    Argues that, as a matter of constitutional law, public school boards of education do not possess unrestricted authority to exclude material from the curriculum on the basis of ideological content, and explores the rights of students and parents to challenge such exclusions. Available from Harvard Civil Rights-Civil Liberties Law Review, Harvard…

  17. Antimicrobial Resistance: Is the World UNprepared?

    Science.gov (United States)

    2016-09-01

    Long Blurb: On September 21st 2016 the United Nations General Assembly convenes in New York, United States to tackle a looming and seemingly inevitable global challenge with the potential to threaten the health and wellbeing of all people: antimicrobial resistance. In an Editorial, the PLOS Medicine Editors reflect on the challenge of coordinating the response to antimicrobial resistance in order to ensure the viability of current antimicrobials and the development of new therapies against resistant pathogens. Short Blurb: In this month's Editorial, the PLOS Medicine Editors reflect on the upcoming United Nations General Assembly meeting which convenes to discuss the global challenge of antimicrobial resistance. PMID:27618631

  18. Effect of different antimicrobial treatments on serum acute phase responses and leukocyte counts in pigs after a primary and a secondary challenge infection with Actinobacillus pleuropneumoniae

    DEFF Research Database (Denmark)

    Sjölund, M; Fossum, C; Martin de la Fuente, AJM;

    2011-01-01

    The susceptibility to an initial challenge and a re-challenge inoculation with Actinobacillus pleuropneumoniae was analysed in pigs that were treated with antimicrobials of different efficacies following the first exposure to A pleuropneumoniae. In brief, 30 nine-week-old specific pathogen......-free pigs were allocated to five groups of six. After acclimatisation, four groups were inoculated with A pleuropneumoniae serotype 2. At the onset of clinical signs, three of the groups of pigs were treated with enrofloxacin, tetracycline or penicillin. A fourth group served as the inoculated control and...

  19. Combating antimicrobial resistance: antimicrobial stewardship program in Taiwan.

    Science.gov (United States)

    Tseng, Shu-Hui; Lee, Chun-Ming; Lin, Tzou-Yien; Chang, Shan-Chwen; Chuang, Yin-Ching; Yen, Muh-Yong; Hwang, Kao-Pin; Leu, Hsieh-Shong; Yen, Che-Chieh; Chang, Feng-Yee

    2012-04-01

    Multi-drug-resistant organisms are increasingly recognized as a global public health issue. Healthcare-associated infection and antimicrobial resistance are also current challenges to the treatment of infectious diseases in Taiwan. Government health policies and the health care systems play a crucial role in determining the efficacy of interventions to contain antimicrobial resistance. National commitment to understand and address the problem is prerequisite. We analyzed and reviewed the antibiotic resistance related policies in Taiwan, USA, WHO and draft antimicrobial stewardship program to control effectively antibiotic resistance and spreading in Taiwan. Antimicrobial stewardship program in Taiwan includes establishment of national inter-sectoral antimicrobial stewardship task force, implementing antimicrobial-resistance management strategies, surveillance of HAI and antimicrobial resistance, conducting hospital infection control, enforcement of appropriate regulations and audit of antimicrobial use through hospital accreditation, inspection and national health insurance payment system. No action today, no cure tomorrow. Taiwan CDC would take a multifaceted, evidence-based approach and make every effort to combat antimicrobial resistance with stakeholders to limit the spread of multi-drug resistant strains and to reduce the generation of antibiotic resistant bacteria in Taiwan. PMID:22483434

  20. Textiles in the Material Practice of Architects – Opportunities, Challenges and Ways of Stimulating Use

    DEFF Research Database (Denmark)

    Wærsted, Elisabeth Heimdal; Lenau, Torben Anker; Brandt, Eva

    This dissertation reports on a design research project about textiles in the material practice of architects. Targeting practicing architects, its aim is to understand how textiles are currently part of their material practice, factors influencing their use and non-use of textiles, and how...... awareness of their benefits may be raised. The project’s three research questions are thus: 1) How are textiles currently used by architects? 2) Which challenges to the use of textiles in architecture can be found in the material practice of architects? 3) How can the use of textiles in architecture...... be stimulated? Based on Donald Schön’s view of design as reflective practice, material practice is defined as how architects work with, choose and apply materials. To reach the aim, the project integrates literature from material science, engineering design, textile engineering and design, as well...

  1. Nanomaterials for Polymer Electrolyte Membrane Fuel Cells; Materials Challenges Facing Electrical Energy Storate

    Energy Technology Data Exchange (ETDEWEB)

    Gopal Rao, MRS Web-Editor; Yury Gogotsi, Drexel University; Karen Swider-Lyons, Naval Research Laboratory

    2010-08-05

    Symposium T: Nanomaterials for Polymer Electrolyte Membrane Fuel Cells Polymer electrolyte membrane (PEM) fuel cells are under intense investigation worldwide for applications ranging from transportation to portable power. The purpose of this seminar is to focus on the nanomaterials and nanostructures inherent to polymer fuel cells. Symposium topics will range from high-activity cathode and anode catalysts, to theory and new analytical methods. Symposium U: Materials Challenges Facing Electrical Energy Storage Electricity, which can be generated in a variety of ways, offers a great potential for meeting future energy demands as a clean and efficient energy source. However, the use of electricity generated from renewable sources, such as wind or sunlight, requires efficient electrical energy storage. This symposium will cover the latest material developments for batteries, advanced capacitors, and related technologies, with a focus on new or emerging materials science challenges.

  2. Antimicrobials, stress and mutagenesis.

    Directory of Open Access Journals (Sweden)

    Alexandro Rodríguez-Rojas

    2014-10-01

    Full Text Available Cationic antimicrobial peptides are ancient and ubiquitous immune effectors that multicellular organisms use to kill and police microbes whereas antibiotics are mostly employed by microorganisms. As antimicrobial peptides (AMPs mostly target the cell wall, a microbial 'Achilles heel', it has been proposed that bacterial resistance evolution is very unlikely and hence AMPs are ancient 'weapons' of multicellular organisms. Here we provide a new hypothesis to explain the widespread distribution of AMPs amongst multicellular organism. Studying five antimicrobial peptides from vertebrates and insects, we show, using a classic Luria-Delbrück fluctuation assay, that cationic antimicrobial peptides (AMPs do not increase bacterial mutation rates. Moreover, using rtPCR and disc diffusion assays we find that AMPs do not elicit SOS or rpoS bacterial stress pathways. This is in contrast to the main classes of antibiotics that elevate mutagenesis via eliciting the SOS and rpoS pathways. The notion of the 'Achilles heel' has been challenged by experimental selection for AMP-resistance, but our findings offer a new perspective on the evolutionary success of AMPs. Employing AMPs seems advantageous for multicellular organisms, as it does not fuel the adaptation of bacteria to their immune defenses. This has important consequences for our understanding of host-microbe interactions, the evolution of innate immune defenses, and also sheds new light on antimicrobial resistance evolution and the use of AMPs as drugs.

  3. New challenges in homeland security: smart advanced materials and structural systems

    Science.gov (United States)

    Wu, H. Felix

    2003-07-01

    September 11th awakened us to the massive damage terrorists can cause with airplanes by bringing down the twin towers of World Trade Center and damaging Wedge-1 of the Pentagon. These incidents represent the worst disaster and loss of lives ever involving a single building structure. The South tower collapsed 56 minutes after the impact, and the North tower collapsed 1 hour and 43 minutes after the impact. Stronger and more durable building materials, as well as fully equipped sensor network monitoring systems may be able to limit structural damages and save lives in the future. America is now facing a great challenge in homeland security, we must build the national measurement infrastructure and develop new technologies that will protect our national infrastructure, strengthen homeland security, and help combat terrorism. The development of Smart Advanced Materials and Structural Systems technologies is one of the key challenges to meeting our national needs.

  4. Progress, challenges, and opportunities for HgCdTe infrared materials and detectors

    Science.gov (United States)

    Lei, Wen; Antoszewski, Jarek; Faraone, Lorenzo

    2015-12-01

    This article presents a review on the current status, challenges, and potential future development opportunities for HgCdTe infrared materials and detector technology. A brief history of HgCdTe infrared technology is firstly summarized and discussed, leading to the conclusion that HgCdTe-based infrared detectors will continue to be a core infrared technology with expanded capabilities in the future due to a unique combination of its favourable properties. Recent progress and the current status of HgCdTe infrared technology are reviewed, including material growth, device architecture, device processing, surface passivation, and focal plane array applications. The further development of infrared applications requires that future infrared detectors have the features of lower cost, smaller pixel size, larger array format size, higher operating temperature, and multi-band detection, which presents a number of serious challenges to current HgCdTe-based infrared technology. The primary challenges include well controlled p-type doping, lower cost, larger array format size, higher operating temperature, multi-band detection, and advanced plasma dry etching. Various new concepts and technologies are proposed and discussed that have the potential to overcome the existing primary challenges that are inhibiting the development of next generation HgCdTe infrared detector technology.

  5. Challenges in bridging theory and applications with examples from Materials Design

    Science.gov (United States)

    Shankar, Sadasivan

    2013-10-01

    Over the past 3 decades the semiconductor industry has doubled the number of transistors on integrated circuits every 2 years, following an empirical law widely known as Moore's law. The ability of the semiconductor industry to stay on Moore's law has enabled the digital revolution and now the convergence of communications and computing. However, as the size of the smallest structures decrease, this has required the introduction of many new materials and the interactions of these heterogeneous materials and processing is increasing in complexity. The increasing use of the nano materials and the ever-shrinking dimensions requires development of an improved understanding of material properties (electronic, thermal, mechanical, and optical) at differences scales. Due to the presence of multiple thin films and metal alloys in the nano technology, grains, and interfaces assume more significance than before. This paper reviews some of the challenges in materials and the opportunities for using fundamental modeling and characterization techniques to enable successful management of these heterogeneous interactions. As the industry evaluates new materials for future technologies, research is needed to develop new modeling and characterization techniques to evaluate nano-materials and materials with nano-scale dimensions and structure.

  6. A Private [School] Matter: The State of Materials Challenges in Private College Preparatory School Libraries in the Southeast United States

    Science.gov (United States)

    Franklin, Renee E.

    2008-01-01

    Materials challenges and censorship occur often in public and private educational settings. Private schools and their library media centers are not subject to the First Amendment but research reported in this article examines the state of challenges to materials held in private schools media centers in the southeast United States as a way to gauge…

  7. Protection and structural materials for fusion reactors: Main challenges, long term materials development needs, differences and commonalities with fission

    International Nuclear Information System (INIS)

    Developing plasma-facing and structural materials with Low nuclear Activation (LA), high heat and radiation resistance, is a challenge that the materials community has to address to enable reliable development and safe operation of fusion reactors in the future. This requires scientific innovation, new knowledge, and the exploration of a range of new materials. To address this challenge, the EU fusion programme has set up a Fusion Materials Topical Group to strengthen coordination of long-term fusion materials development for DEMO, and to undertake physically based modelling of radiation induced microstructure and degradation of mechanical properties required to guide the experimental developments. In this paper we describe main radiation effects induced by the intense flux of 14 MeV neutrons in the reference structural materials (i) for Tritium-Breeding Blanket (TBB) modules, LA Ferritic/Martensitic Steel EUROFER, Oxide Dispersion (ODS) EUROFER and ODS ferritic steels, and, (ii) for the divertor, W and W-alloys. Specific issues concerning the peculiar microstructure induced by the impact of α particles on the surface of tungsten, foreseen as a reference protection material, will also be discussed. Modelling radiation effects in EUROFER under fusion reactor relevant conditions is the first priority for the programme, in order to inter-correlate the data obtained with various neutron spectra, contribute to the definition of the irradiation matrix in the future intense source of 14 MeV neutrons, IFMIF, and bring comprehensive understanding and extrapolation capabilities towards the very large range of DEMO operating conditions. Formulating and developing predictive modelling tools is therefore a task of prime significance. Particular care has been taken (i) to focus the modelling effort on the scale where physics can be mastered, i.e. on the scale of the chemical bond, which is triggered by electronic correlation in the case of Fe-Cr system and body cubic centred

  8. Microbial challenge promotes the regenerative process of the injured central nervous system of the medicinal leech by inducing the synthesis of antimicrobial peptides in neurons and microglia

    Science.gov (United States)

    Schikorski, David; Cuvillier-Hot, Virginie; Leippe, Matthias; Boidin-Wichlacz, Céline; Slomianny, Christian; Macagno, Eduardo; Salzet, Michel; Tasiemski, Aurélie

    2010-01-01

    Following trauma, the central nervous system (CNS) of the medicinal leech, unlike the mammalian CNS, has a strong capacity to regenerate neurites and synaptic connections that restore normal function. Here, we show that this regenerative process is enhanced by a controlled bacterial infection, suggesting that induction of regeneration of normal CNS function may depend critically upon the co-initiation of an immune response. We explore the interaction between the activation of a neuroimmune response and the process of regeneration by assaying the potential roles of two newly characterized antimicrobial peptides. Our data provide evidence that microbial components differentially induce the transcription, by microglial cells, of both antimicrobial peptide genes, the products of which accumulate rapidly at sites in the CNS undergoing regeneration following axotomy. Using a preparation of leech CNS depleted of microglial cells, we also demonstrate the production of antimicrobial peptides by neurons. Interestingly, in addition to exerting antibacterial properties, both peptides act as promoters of the regenerative process of axotomized leech CNS. These data are the first to report the neuronal synthesis of antimicrobial peptides and their participation in the immune response and the regeneration of the CNS. Thus, the leech CNS appears as an excellent model for studying the implication of immune molecules in neural repair. PMID:18606660

  9. Laser powder bed fusion additive manufacturing of metals; physics, computational, and materials challenges

    International Nuclear Information System (INIS)

    The production of metal parts via laser powder bed fusion additive manufacturing is growing exponentially. However, the transition of this technology from production of prototypes to production of critical parts is hindered by a lack of confidence in the quality of the part. Confidence can be established via a fundamental understanding of the physics of the process. It is generally accepted that this understanding will be increasingly achieved through modeling and simulation. However, there are significant physics, computational, and materials challenges stemming from the broad range of length and time scales and temperature ranges associated with the process. In this paper, we review the current state of the art and describe the challenges that need to be met to achieve the desired fundamental understanding of the physics of the process

  10. Laser powder bed fusion additive manufacturing of metals; physics, computational, and materials challenges

    Energy Technology Data Exchange (ETDEWEB)

    King, W. E., E-mail: weking@llnl.gov [Physical and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Anderson, A. T.; Ferencz, R. M.; Hodge, N. E.; Khairallah, S. A. [Engineering Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Kamath, C. [Computation Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Rubenchik, A. M. [NIF and Photon Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2015-12-15

    The production of metal parts via laser powder bed fusion additive manufacturing is growing exponentially. However, the transition of this technology from production of prototypes to production of critical parts is hindered by a lack of confidence in the quality of the part. Confidence can be established via a fundamental understanding of the physics of the process. It is generally accepted that this understanding will be increasingly achieved through modeling and simulation. However, there are significant physics, computational, and materials challenges stemming from the broad range of length and time scales and temperature ranges associated with the process. In this paper, we review the current state of the art and describe the challenges that need to be met to achieve the desired fundamental understanding of the physics of the process.

  11. Current progress and future challenges in thermoelectric power generation: From materials to devices

    International Nuclear Information System (INIS)

    Thermoelectric power generation (TEG) represents one of the cleanest methods of energy conversion available today. It can be used in applications ranging from the harvesting of waste heat to conversion of solar energy into useful electricity. Remarkable advances have been achieved in recent years for various thermoelectric (TE) material systems. The introduction of nanostructures is used to tune the transport of phonons, while band structure engineering allows for the tailoring of electron transport. In this overview, top-down approaches to phonon engineering, such as atomic construction of new materials, will be reviewed. Bottom-up approaches to electron engineering, such as the formation of ordered nanostructures, will also be discussed. The assembly of TEG devices is still particularly challenging, and consequently, thermal-to-electric conversion utilizing these devices has been realized only in niche applications. In this review paper, we will discuss some of the challenges that must be overcome to enable widespread use of TE devices. These include thermal stability at the material level, and reliable contact at the device level

  12. Space Nuclear Power and Propulsion: Materials Challenges for the 21st Century

    Science.gov (United States)

    Houts, Mike

    2008-01-01

    The current focus of NASA s space fission effort is Fission Surface Power (FSP). FSP systems could be used to provide power anytime, anywhere on the surface of the Moon or Mars. FSP systems could be used at locations away from the lunar poles or in permanently shaded regions, with no performance penalty. A potential reference 40 kWe option has been devised that is cost-competitive with alternatives while providing more power for less mass. The potential reference system is readily extensible for use on Mars. At Mars the system could be capable of operating through global dust storms and providing year-round power at any Martian latitude. To ensure affordability, the potential near-term, 40 kWe reference concept is designed to use only well established materials and fuels. However, if various materials challenges could be overcome, extremely high performance fission systems could be devised. These include high power, low mass fission surface power systems; in-space systems with high specific power; and high performance nuclear thermal propulsion systems. This tutorial will provide a brief overview of space fission systems and will focus on materials challenges that, if overcome, could help enable advanced exploration and utilization of the solar system.

  13. Membranes from nanoporous 1D and 2D materials: A review of opportunities, developments, and challenges

    KAUST Repository

    Kim, Wun-gwi

    2013-12-01

    Membranes utilizing nanoporous one-dimensional (1D) and two-dimensional (2D) materials are emerging as attractive candidates for applications in molecular separations and related areas. Such nanotubular and nanolayered materials include carbon nanotubes, metal oxide nanotubes, layered zeolites, porous layered oxides, layered aluminophosphates, and porous graphenes. By virtue of their unique shape, size, and structure, they possess transport properties that are advantageous for membrane and thin film applications. These materials also have very different chemistry from more conventional porous 3D materials, due to the existence of a large, chemically active, external surface area. This feature also necessitates the development of innovative strategies to process these materials into membranes and thin films with high performance. This work provides the first comprehensive review of this emerging area. We first discuss approaches for the synthesis and structural characterization of nanoporous 1D and 2D materials. Thereafter, we elucidate different approaches for fabrication of membranes and thin films from these materials, either as multiphase (composite/hybrid) or single-phase membranes. The influence of surface chemistry and processing techniques on the membrane morphology is highlighted. We then discuss the applications of such membranes in areas relating to molecular transport and separation, e.g. gas and liquid-phase separations, water purification, and ion-conducting membranes. The review concludes with a discussion of the present outlook and some of the key scientific challenges to be addressed on the path to industrially applicable membranes containing nanoporous 1D and 2D materials. © 2013 Elsevier Ltd.

  14. Development of highly-filled, bioactive acrylic-based composite bone cements for orthopedic and craniofacial surgery: Tuning of material properties after incorporation of calcium phosphate and antimicrobial fillers

    Science.gov (United States)

    Rodriguez, Lucas Carlos

    Bone cements are used in a variety of healthcare specialties ranging from orthopedics to dentistry to craniofacial surgery to spinal disc reconstruction. These materials need characteristics which mimic their surrounding tissues. Currently available materials have struggled to maintain these necessary characteristics. Poly (methyl methacrylate) is a very high strength bio-inert polymer which has been utilized in healthcare since the 1940's. Calcium phosphate cements are well established as being bone mimicking, but cannot sustain the compressive loads in a weight bearing application. This study sought to solve the problem of currently available bone cements by filling calcium phosphates and antimicrobials into an acrylic polymer matrix. The intended outcome was a material capable of retaining high mechanical stability from the acrylic polymer phase, while becoming sufficiently bone mimicking and antimicrobial. This thesis work presented, characterizes the material properties of the developed materials and eventually isolates a material of interest for future studies.

  15. Evaluation of the Antimicrobial Activity of Nanostructured Materials of Titanium Dioxide Doped with Silver and/or Copper and Their Effects on Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Cristina Garcidueñas-Piña

    2016-01-01

    Full Text Available Nanostructured materials (NSMs of silver (Ag@TiO2 and copper (TiO2-Cu2+ doped titanium dioxide were synthesized, fully characterized, and evaluated for their antimicrobial efficiency and effects on Arabidopsis thaliana. The NSMs were prepared using an environmentally benign route. The physicochemical properties of the materials were determined with analytical techniques. These materials are active under visible light, exhibit a small size (10–12 nm, are crystalline (anatase, and liberate metal ions (Ag+ and Cu2+ in solution. Microbicide activity was observed in E. coli C600 and S. cerevisiae W303 strains treated with several concentrations of Ag@TiO2 and TiO2-Cu2+, radiated and nonradiated, and after different times. Higher inactivation was achieved with Ag@TiO2 in E. coli, with value of log inactivation of 2.2 with 0.5 mg/mL after 4 h, than in S. cerevisiae, with a log inactivation of 2.6 with 10 mg/mL after 24 h. The impact of these NSMs in plants was evaluated in Arabidopsis thaliana Col-0 strain exposed to such materials at different conditions and concentrations, and physical and biochemical effects were analyzed. Seeds exposed to NSMs did not show effects on germination and growth. However, seedlings treated with these materials modified their growth and their total chlorophyll content.

  16. Investigation of ultrafast laser photonic material interactions: challenges for directly written glass photonics

    CERN Document Server

    Ams, M; Dekker, P; Dubov, M; Mezentsev, V K; Bennion, I; Withford, M J

    2008-01-01

    Currently, direct-write waveguide fabrication is probably the most widely studied application of femtosecond laser micromachining in transparent dielectrics. Devices such as buried waveguides, power splitters, couplers, gratings and optical amplifiers have all been demonstrated. Waveguide properties depend critically on the sample material properties and writing laser characteristics. In this paper we discuss the challenges facing researchers using the femtosecond laser direct-write technique with specific emphasis being placed on the suitability of fused silica and phosphate glass as device hosts for different applications.

  17. The national system of nuclear material control development and challenges. Vol. 3

    International Nuclear Information System (INIS)

    This paper presents the major factors which may affect the implementation of the National System of Nuclear Material Accounting and Safeguards in Egypt. Developments of this National System-being a division of the Nuclear Regulatory Body in the country-are discussed. Also, recent requirements of the International Atomic Energy Agency within the policy of strengthening its regime of international nuclear control are reviewed. The challenges facing the National System are indicated taking in consideration the anticipated growth in the nuclear field in Egypt by the year 2000 and after. 2 figs

  18. Laser-assisted metal spinning for an efficient and flexible processing of challenging materials

    Science.gov (United States)

    Brummer, C.; Eck, S.; Marsoner, S.; Arntz, K.; Klocke, F.

    2016-03-01

    The demand for components made from high performance materials like titanium or nickel-based alloys as well as strain-hardening stainless steel is steadily increasing. However, conventional forming operations conducted on these materials are generally very laborious and time-consuming. This is where the limitations of metal spinning also become apparent. Using a laser to apply heat localized to the forming zone during metal spinning facilitates to enhance the formability of a material. In order to analyse the potential of the new manufacturing process, experimental investigations on laser-assisted shear forming and multi-pass metal spinning have been performed with austenitic stainless steel X5CrNi18-10, nickel-based alloy Inconel 718 and titanium grade 2. It could be demonstrated that the formability of these materials can be enhanced by laser-assistance. Besides the resulting enhancement of forming limits for metal spinning of challenging materials, the forming forces were reduced and the product quality was improved significantly.

  19. New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens

    International Nuclear Information System (INIS)

    Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells. - Highlights: • The novel antimicrobial inhibits growth of clinical staphylococci and enterococci. • The novel antimicrobial inhibits growth of Legionella in drinking water. • A putative mode of action of the antimicrobial coating is presented

  20. New antimicrobial contact catalyst killing antibiotic resistant clinical and waterborne pathogens

    Energy Technology Data Exchange (ETDEWEB)

    Guridi, A. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Diederich, A.-K. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Aguila-Arcos, S.; Garcia-Moreno, M. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Blasi, R.; Broszat, M. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Schmieder, W.; Clauss-Lendzian, E. [Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany); Sakinc-Gueler, T. [University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Andrade, R. [Advanced Research Facilities (SGIker), University of the Basque Country, UPV/EHU, 48940 Leioa (Spain); Alkorta, I. [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); Meyer, C.; Landau, U. [Largentec GmbH, Am Waldhaus 32, 14129 Berlin (Germany); Grohmann, E., E-mail: elisabeth.grohmann@googlemail.com [Biophysics Unit (CSIC, UPV/EHU), Department of Biochemistry and Molecular Biology, University of the Basque Country, 48940 Leioa (Spain); University Medical Center Freiburg, Division of Infectious Diseases, Hugstetter Strasse 55, 79106 Freiburg (Germany); Biology II, Microbiology, Albert-Ludwigs-University Freiburg, Schänzlestrasse 1, 79104 Freiburg (Germany)

    2015-05-01

    Microbial growth on medical and technical devices is a big health issue, particularly when microorganisms aggregate to form biofilms. Moreover, the occurrence of antibiotic-resistant bacteria in the clinical environment is dramatically growing, making treatment of bacterial infections very challenging. In search of an alternative, we studied a novel antimicrobial surface coating based on micro galvanic elements formed by silver and ruthenium with surface catalytic properties. The antimicrobial coating efficiently inhibited the growth of the nosocomial pathogens Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Enterococcus faecium as demonstrated by the growth inhibition on agar surface and in biofilms of antibiotic resistant clinical E. faecalis, E. faecium, and S. aureus isolates. It also strongly reduced the growth of Legionella in a drinking water pipeline and of Escherichia coli in urine. We postulate a mode of action of the antimicrobial material, which is independent of the release of silver ions. Thus, the novel antimicrobial coating could represent an alternative to combat microbial growth avoiding the toxic side effects of high levels of silver ions on eukaryotic cells. - Highlights: • The novel antimicrobial inhibits growth of clinical staphylococci and enterococci. • The novel antimicrobial inhibits growth of Legionella in drinking water. • A putative mode of action of the antimicrobial coating is presented.

  1. Dealing with the regional challenge of physical protection of nuclear materials

    International Nuclear Information System (INIS)

    Full text: The problem of protecting sensitive fissile and fissionable nuclear materials of misuses by governments has been the subject of the convention on physical protection of nuclear material (CPPNM), which entered into force on February 8, 1987. However, in May 2001 the final report of the expert meeting had already recognized 'a clear need to strengthen the international physical protection regime'. The board of governors of the International Atomic Energy Agency (IAEA) decided then to convene a group, which would meet in Vienna from 3 to 7 December 2001, to draft on amendment to the CPPNM. The tragic occurrences of September 11, 2001, however, changed the then generally accepted view on the problem of physical protection, because nuclear materials had to be protected from falling into the hands of terrorists rather than of governments thirst of nuclear sensitive materials. Moreover, crude explosive devices could be made by terrorists, or hired scientists, using readily available radioactive materials, like 226Ra or 137Cs to inflict damage to civilians. Thus physical protection of those and other radioactive materials became an instant challenge for national and international authorities to prevent the use of such materials in terrorist actions. The prevention of illicit trafficking of radioactive materials is now in the priority list of these authorities. Fortunately; an international conference on 'Measures to Detect, Intercept and Respond to the Illicit Uses of Nuclear Materials and Radioactive Sources' was held in Stockholm, Sweden, in May 2001. An IAEA document - GOV/2001/37-GC(45)/20 - recommended in its plan of activities a series of projects to be implemented between 2002 and 2005, which included developing and providing assistance for the application of: (i) standards for physical protection of nuclear materials and nuclear facilities in member states; (ii) norms and guidelines for nuclear material accounting and control in member states; (iii

  2. Catalysis:An old but new challenge for graphene-based materials

    Institute of Scientific and Technical Information of China (English)

    Ljubisa R. Radovic; Camila Mora-Vilches; Adolfo J. A. Salgado-Casanova

    2014-01-01

    An assessment is offered regarding the progress made, and the remaining challenges, in the field of carbocatalysis. The fundamental principles that govern the preparation and performance of sp2-hybridized carbon materials in heterogeneous catalysis have been known for decades, and the level of understanding of key issues-especially the importance of textural and ion-exchange prop-erties (i.e., surface area, pore size distribution, and proton transfer)-remains quite satisfactory. The opportunities for novel catalytic materials-especially graphene nanosheets and carbon nanotubes-are tremendous, especially when it comes to taking advantage of their structural order, such that electron transfer can be both better understood and controlled to enhance catalytic activity and selectivity.

  3. The challenge of identifying non-intentionally added substances from food packaging materials: a review.

    Science.gov (United States)

    Nerin, C; Alfaro, P; Aznar, M; Domeño, C

    2013-05-01

    Packaged food can contain non-intentionally added substances (NIAS) as a result of reaction and degradation processes or the presence of impurities in the raw materials used for the packaging production. This manuscript reviews the evidence of NIAS and their possible origin. One of the most challenging and difficult tasks when a sample of packaging materials arrives at the laboratory is knowing the procedure to apply for identifying the unknown compounds. This work proposes an analytical procedure for sample treatment, applicable to polymers as well as to migration samples, and for NIAS identification. The identification protocol comprises the determination of both volatile and non-volatile compounds. A review is presented of the most novel analytical techniques used for identification purposes, particularly high resolution mass spectrometry (HRMS). PMID:23601971

  4. Needs and challenges of using enrichment materials in the pig industry

    Directory of Open Access Journals (Sweden)

    Caio Abércio da Silva

    2016-02-01

    Full Text Available Pigs have certain needs that, when unfulfilled, can affect their behavior and their productive efficiency thus promoting welfare problems. Exploration and the search for food are inherent behaviors in pigs at all stages of production, and nest preparation is an exclusive antepartum need for females. In intensive rearing units, providing environmental enrichment materials is a way to meet these needs that allows the animals to fully express their behavior and avoid problems such as tail biting, stereotypes and, specifically in the case of breeding arrays, the onset of labor due to stress, which can result in impaired births and piglets. Straw is known as an enrichment material that best meets these demands, and it is an important requirement of animal welfare legislation in several countries. This study was developed to highlight the importance of meeting the biological needs of pigs through the provision of environmental enrichment materials and to demonstrate the positive results that these materials have on pig welfare. The challenges to the viability of the regular use of these resources in industrial pig farming are also addressed.

  5. Novel Formulations for Antimicrobial Peptides

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2014-10-01

    Full Text Available Peptides in general hold much promise as a major ingredient in novel supramolecular assemblies. They may become essential in vaccine design, antimicrobial chemotherapy, cancer immunotherapy, food preservation, organs transplants, design of novel materials for dentistry, formulations against diabetes and other important strategical applications. This review discusses how novel formulations may improve the therapeutic index of antimicrobial peptides by protecting their activity and improving their bioavailability. The diversity of novel formulations using lipids, liposomes, nanoparticles, polymers, micelles, etc., within the limits of nanotechnology may also provide novel applications going beyond antimicrobial chemotherapy.

  6. Dynamics of aluminum use in the global passenger car system: Challenges and solutions of recycling and material substitution

    OpenAIRE

    Modaresi, Roja

    2015-01-01

    This thesis analyzes the relationship between the design of vehicles, end-of-life vehicle (ELV) management, and global material production using aluminum as an example. Vehicle manufacturing, material industries and ELV management face different challenges. An important challenge for vehicle manufacturers is the design of lightweight vehicles to reduce energy use and greenhouse gas (GHG) emissions in the use phase for which an increased use of aluminum of different alloys is an...

  7. Triclosan antimicrobial polymers

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2016-03-01

    Full Text Available Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are enhanced even better through secondary bonding relationships. Further, polymer blend compatibilization is considered due to similar molecular relationships and polarities. With compatibilization of triclosan in polymers a more uniform stability for nonpolar triclosan in the polymer solid state is retained by the antimicrobial for extremely low release with minimum solubility into aqueous solution. As a result, triclosan is projected for long extended lifetimes as an antimicrobial polymer additive. Further, triclosan rapid alternating ether bond rotations disrupt secondary bonding between chain monomers in the resin state to reduce viscosity and enhance polymer blending. Thus, triclosan is considered for a polymer additive with multiple properties to be an antimicrobial with additional benefits as a nonpolar toughening agent and a hydrophobic wetting agent. The triclosan material relationships with alternating ether bond rotations are described through a complete different form of medium by comparisons with known antimicrobial properties that upset bacterial cell membranes through rapid fluctuating mechanomolecular energies. Also, triclosan bond entanglements with secondary bonding can produce structural defects in weak bacterial lipid membranes requiring pliability that can then interfere with cell division. Regarding applications with polymers, triclosan can be incorporated by mixing into a resin system before cure, melt mixed with thermoplastic polymers

  8. Regulatory challenges in the management of aging of structural materials in nuclear power plants

    International Nuclear Information System (INIS)

    The article discusses two major pathways by which a regulatory body, and in particular the CSN, may participate in the acquisition of the necessary knowledge on mechanisms of aging of nuclear structural materials: to participate in forums to share operational experience and R and R project, both nationally and internationally. It notes the importance of this participation to carry out its regulatory function based on the knowledge acquired and the unique challenge of transferring that knowledge to rules and guidelines for their application. The article discusses various R and D projects in which the CSN participates directly. It calls for the presence of regulatory bodies in R and D project funded by the EU and the transfer of the results of such projects to codes, standards or guidelines for feasible implementation. (Author)

  9. Triclosan antimicrobial polymers

    OpenAIRE

    Petersen, Richard C.

    2016-01-01

    Triclosan antimicrobial molecular fluctuating energies of nonbonding electron pairs for the oxygen atom by ether bond rotations are reviewed with conformational computational chemistry analyses. Subsequent understanding of triclosan alternating ether bond rotations is able to help explain several material properties in Polymer Science. Unique bond rotation entanglements between triclosan and the polymer chains increase both the mechanical properties of polymer toughness and strength that are ...

  10. Technical and management challenges associated with structural materials degradation in nuclear reactors in the future

    International Nuclear Information System (INIS)

    There are active plans worldwide to increase nuclear power production by significant amounts. In the near term (i.e. by 2020) this will be accomplished by, (a) increasing the power output of the existing reactors and extending their life, and by, (b) constructing new reactors that are very similar to the current water-cooled designs. Beyond 2025-2030, it is possible that new reactors (i.e. the 'GEN IV' designs) will be very different from those currently in service. A full discussion of the technical and management concerns associated with materials degradation that might arise over the next 40 years would need to address a wide range of topics. Quite apart from discussing the structural integrity issues for the materials of construction and the fuel cladding, the debate would also need to cover, for example, fuel resources and the associated issues of fuel cycle management and waste disposal, manufacturing capacity, inspection capabilities, human reliability, etc., since these all impact to one degree or another on the choice of material and the reactor operating conditions. For brevity, the scope of this article is confined to the integrity of the materials of construction for passive components in the current water-cooled reactors and the evolutionary designs (which will dominate the near term new constructions), and the very different GEN IV reactor designs. In all cases the operating environments will be more aggressive than currently encountered. For instance, the concerns for flow accelerated corrosion and flow-induced vibration will be increased under extended power uprate conditions for the current water-cooled reactors. Of greater concern, the design life will be at least 60 years for all of the new reactors and for those current reactors operating with extended licenses. This automatically presents challenges with regard to managing both irradiation damage in metallic and non-metallic materials of construction, and environmentally assisted cracking. This

  11. Antimicrobial technology in orthopedic and spinal implants

    Science.gov (United States)

    Eltorai, Adam EM; Haglin, Jack; Perera, Sudheesha; Brea, Bielinsky A; Ruttiman, Roy; Garcia, Dioscaris R; Born, Christopher T; Daniels, Alan H

    2016-01-01

    Infections can hinder orthopedic implant function and retention. Current implant-based antimicrobial strategies largely utilize coating-based approaches in order to reduce biofilm formation and bacterial adhesion. Several emerging antimicrobial technologies that integrate a multidisciplinary combination of drug delivery systems, material science, immunology, and polymer chemistry are in development and early clinical use. This review outlines orthopedic implant antimicrobial technology, its current applications and supporting evidence, and clinically promising future directions. PMID:27335811

  12. Synthesis and comparative study on the antimicrobial activity of hybrid materials based on silver nanoparticles (AgNps) stabilized by polyvinylpyrrolidone (PVP).

    Science.gov (United States)

    Bryaskova, Rayna; Pencheva, Daniela; Nikolov, Stanislav; Kantardjiev, Todor

    2011-10-01

    Hybrid materials based on polyvinylpyrrolidone (PVP) with silver nanoparticles (AgNps) were synthesized applying two different strategies based on thermal or chemical reduction of silver ions to silver nanoparticles using PVP as a stabilizer. The formation of spherical silver nanoparticles with diameter ranging from 9 to 16 nm was confirmed by TEM analysis. UV-vis and FTIR spectroscopy were also applied to confirm the successful formation of AgNps. The antibacterial activity of the synthesized AgNPs/PVP against etalon strains of three different groups of bacteria-Staphylococcus aureus (S. aureus; gram-positive bacteria), Escherichia coli (E. coli; gram-negative bacteria), Pseudomonas aeruginosa (P. aeruginosa; non-ferment gram-negative bacteria), as well as against spores of Bacillus subtilis (B. subtilis) was studied. AgNps/PVP were tested for the presence of fungicidal activity against different yeasts and mold such as Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Aspergillus brasiliensis. The hybrid materials showed a strong antimicrobial effect against the tested bacterial and fungal strains and therefore have potential applications in biotechnology and biomedical science. PMID:22837793

  13. Lead-Cooled Fast Reactor Systems and the Fuels and Materials Challenges

    Directory of Open Access Journals (Sweden)

    T. R. Allen

    2007-01-01

    Full Text Available Anticipated developments in the consumer energy market have led developers of nuclear energy concepts to consider how innovations in energy technology can be adapted to meet consumer needs. Properties of molten lead or lead-bismuth alloy coolants in lead-cooled fast reactor (LFR systems offer potential advantages for reactors with passive safety characteristics, modular deployment, and fuel cycle flexibility. In addition to realizing those engineering objectives, the feasibility of such systems will rest on development or selection of fuels and materials suitable for use with corrosive lead or lead-bismuth. Three proposed LFR systems, with varying levels of concept maturity, are described to illustrate their associated fuels and materials challenges. Nitride fuels are generally favored for LFR use over metal or oxide fuels due to their compatibility with molten lead and lead-bismuth, in addition to their high atomic density and thermal conductivity. Ferritic/martensitic stainless steels, perhaps with silicon and/or oxide-dispersion additions for enhanced coolant compatibility and improved high-temperature strength, might prove sufficient for low-to-moderate-temperature LFRs, but it appears that ceramics or refractory metal alloys will be necessary for higher-temperature LFR systems intended for production of hydrogen energy carriers.

  14. Challenges in high temperature low cycle fatigue testing of metallic materials

    International Nuclear Information System (INIS)

    The evaluation of the high strain Low Cycle Fatigue properties of structural materials is an involved and complicated procedure requiring skill and diligence from the experimentalist. This presentation describes the various testing methods to evaluate the LCF properties of structural materials, the complexities involved and some solutions to exacting requirements, not covered by the testing procedure standards. The basic components of servo-hydraulic fatigue testing machines is described, as are the calibration and maintenance procedures. Results of LCF tests conducted at the authors' laboratory on AISI 316L(N) stainless steel and Mod.9Cr-1Mo ferritic steel are described. The complications in total strain controlled testing of weld joints is brought out and soft zone development in Mod. 9Cr-1Mo ferritic steel is described. The special requirements for testing in environmental chambers is a challenging task. In-house chambers, designed to carry out testing in dynamic sodium environment is highlighted. These chambers have provision to accommodate extensometers for strain measurements, and also house all the safety instrumentation needed to carry out to mechanical testing in dynamic sodium environment. The variation of LCF results as a function of specimen geometry is examined. The various failure criteria adopted by laboratories in different countries are also touched upon. (author)

  15. Revisiting the Challenges in Fabricating Uniform Coatings with Polyfunctional Molecules on High Surface Energy Materials

    Directory of Open Access Journals (Sweden)

    Stephanie Oyola-Reynoso

    2015-12-01

    Full Text Available Modifying the chemistry of a surface has been widely used to influence interfacial properties of a material or nature of interaction between two materials. This article provides an overview on the role of polyfunctional molecules, specifically silanes, in surface modification of polar surfaces (bearing soft nucleophiles. An emphasis on the mechanism of the reaction in the presence of adsorbed water, where the modifying reagents are hydrolysable, is discussed. To highlight the complexity of the reaction, modification of paper with trichlorosilanes is highlighted. Preparation of hydrophobic cellulosic paper, and structure–property relations under different treatment conditions is used to highlight that a monolayer is not always formed during the surface modification. Gel-formation via step-growth polymerization suggests that at the right monomer:adsorbed water ratio, a monolayer will not form but rather self-assembly driven particle formation will occur leading to a textured surface. The review highlights recent work indicating that the focus on monolayer formation, is at the very least, not always the case but gel formation, with concomitant self-assembly, might be the culprit in understanding challenges associated with the use of polyfunctional molecules in surface modification.

  16. Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives

    International Nuclear Information System (INIS)

    The increasing penetration of renewable energy and the trend toward clean, efficient transportation have spurred growing interests in sodium-beta alumina batteries that store electrical energy via sodium ion transport across a β''-Al2O3 solid electrolyte at elevated temperatures (typically 300-350 C). Currently, the negative electrode or anode is metallic sodium in molten state during battery operation; the positive electrode or cathode can be molten sulfur (Na-S battery) or solid transition metal halides plus a liquid phase secondary electrolyte (e.g., ZEBRA battery). Since the groundbreaking works in the sodium-beta alumina batteries a few decades ago, encouraging progress has been achieved in improving battery performance, along with cost reduction. However, there remain issues that hinder broad applications and market penetration of the technologies. To better the Na-beta alumina technologies require further advancement in materials along with component and system design and engineering. This paper offers a comprehensive review on materials of electrodes and electrolytes for the Na-beta alumina batteries and discusses the challenges ahead for further technology improvement. (author)

  17. Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Sigrid Mayrhofer

    2011-01-01

    Full Text Available Strains of the genus Bifidobacterium are frequently used as probiotics, for which the absence of acquired antimicrobial resistance has become an important safety criterion. This clarifies the need for antibiotic susceptibility data for bifidobacteria. Based on a recently published standard for antimicrobial susceptibility testing of bifidobacteria with broth microdilution method, the range of susceptibility to selected antibiotics in 117 animal bifidobacterial strains was examined. Narrow unimodal MIC distributions either situated at the low-end (chloramphenicol, linezolid, and quinupristin/dalfopristin or high-end (kanamycin, neomycin concentration range could be detected. In contrast, the MIC distribution of trimethoprim was multimodal. Data derived from this study can be used as a basis for reviewing or verifying present microbiological breakpoints suggested by regulatory agencies to assess the safety of these micro-organisms intended for the use in probiotics.

  18. Antimicrobial resistance

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    -the-counter sale of antibiotics, the use of antimicrobial stewardship programmes, the active participation of clinicians in audits, the utilization of valid rapid point-of-care tests, the promotion of delayed antibiotic prescribing strategies, the enhancement of communication skills with patients with the aid...... of information brochures and the performance of more pragmatic studies in primary care with outcomes that are of clinicians' interest, such as complications and clinical outcomes....

  19. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring System About NARMS Bacteria (NARMS) NARMS at Work Reports ...

  20. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... 08 Animation of Antimicrobial Resistance (text version) Arabic Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) Chinese Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) French ...

  1. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of Antimicrobial Resistance Share Tweet Linkedin Pin it ... Veterinary Medicine is cited as the corporate author. Animation Animation of Antimicrobial Resistance (WMV - 19.2MB) 9: ...

  2. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... how antimicrobial resistance both emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial ...

  3. Food safety concerns deriving from the use of silver based food packaging materials

    OpenAIRE

    Pezzuto, Alessandra; Losasso, Carmen; Mancin, Marzia; Gallocchio, Federica; Piovesana, Alessia; Binato, Giovanni; Gallina, Albino; Marangon, Alberto; Mioni, Renzo; Favretti, Michela; Ricci, Antonia

    2015-01-01

    The formulation of innovative packaging solutions, exerting a functional antimicrobial role in slowing down food spoilage, is expected to have a significant impact on the food industry, allowing both the maintenance of food safety criteria for longer periods and the reduction of food waste. Different materials are considered able to exert the required antimicrobial activity, among which are materials containing silver. However, challenges exist in the application of silver to food contact mat...

  4. Antimicrobial beeswax coated polylactide films with silver control release capacity.

    Science.gov (United States)

    Martínez-Abad, Antonio; Lagarón, Jose Maria; Ocio, María Jose

    2014-03-17

    Although the application of silver based antimicrobial systems is a widespread technology, its implementation in areas such as food packaging is still challenging. The present paper describes the fabrication of poly(lactic acid) (PLA) coated with beeswax with controlled release properties for sustained antimicrobial performance. Release of silver ions from the polymers was monitored voltammetrically under various conditions (surface contact, immersion in various liquid media and at different pH values) throughout at least 7days. A higher release was noted with decreasing pH while surface release was much slower than the release when immersed in liquid medium. While uncoated films demonstrated a high burst release which in some instances implied surpassing some current migration restrictions (food), the addition of a beeswax layer allowed a sustained release of the antimicrobial compound. Increasing the thickness of the beeswax layer resulted in an increase in the water barrier properties of the films while reducing the relatively constant values of sustained release. Antimicrobial performance was correlated with the release of silver ions, indicating threshold concentrations for biocide action of materials for food packaging or other migration sensitive applications. PMID:24448276

  5. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring System ... Note: If you need help accessing information in different file formats, see Instructions for Downloading ...

  6. The potential, limitations, and challenges of divide and conquer quantum electronic structure calculations on energetic materials.

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Jon R.; Magyar, Rudolph J.

    2012-02-01

    High explosives are an important class of energetic materials used in many weapons applications. Even with modern computers, the simulation of the dynamic chemical reactions and energy release is exceedingly challenging. While the scale of the detonation process may be macroscopic, the dynamic bond breaking responsible for the explosive release of energy is fundamentally quantum mechanical. Thus, any method that does not adequately describe bonding is destined to lack predictive capability on some level. Performing quantum mechanics calculations on systems with more than dozens of atoms is a gargantuan task, and severe approximation schemes must be employed in practical calculations. We have developed and tested a divide and conquer (DnC) scheme to obtain total energies, forces, and harmonic frequencies within semi-empirical quantum mechanics. The method is intended as an approximate but faster solution to the full problem and is possible due to the sparsity of the density matrix in many applications. The resulting total energy calculation scales linearly as the number of subsystems, and the method provides a path-forward to quantum mechanical simulations of millions of atoms.

  7. Parabolic Flight Evaluation of Bacterial Adhesion on Multiple Antimicrobial Surface Treatments

    Science.gov (United States)

    Birmele, Michele

    2011-01-01

    This report describes the development of a test method and the evaluation of the effectiveness of antimicrobial technologies in reduced gravity based on parabolic flight experiments. Microbial growth is a common occurrence on fully immersed wetted surfaces in spacecraft environmental control and life support systems despite the use of chemical and/or physical \\disinfection. Many materials and surface treatments with antimicrobial properties are commercially available but none have been vetted for spaceflight applications. Herein a test method is explained that included ground and reduced gravity parabolic flight experiments with a standard microorganism recovered from spacecraft, Pseudomonas aeruginosa, added at a concentration of 1 x 10(exp 5) cells per milliliter (mL) onto challenge material coupon surfaces. Several experimental materials were observed to slightly reduce microbial attachment in reduced gravity flight experiments, but none were capable of eliminating all challenge bacteria. Lunar gravity had an increased antimicrobial effect in 28 out of 36 test coupons compared to microgravity when provided otherwise identical conditions for growth, suggesting trace .amounts of gravity may be required for maximum antimicrobial performance. Bacterial cells exposed to variable gravity had more than twice as ,much intracellular adenosine triphosphate (ATP) when compared to control cells exposed only to Earth gravity due to a short duration response to environmental stress. An ATP luminescence assay was the method most amenable to development of an in-flight microbial monitoring assay

  8. Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

    OpenAIRE

    EllenK.Silbergeld; YaqiYou

    2014-01-01

    Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance. Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome ...

  9. Assessment of Challenges in Developing Self-Instructional Course Materials at the National Open University of Nigeria

    Directory of Open Access Journals (Sweden)

    Charity Akuadi Okonkwo

    2012-04-01

    Full Text Available The National Open University of Nigeria (NOUN is Nigeria’s only university dedicated to providing education through the use of distance instructional methods. So far, however, the lack of availability and poor distribution of course materials, which underpin instructional delivery at NOUN, continue to be hindrances to achieving the university’s vision and mission. There are delays and difficulties in developing and distributing materials to students and Study Centres. Many pioneer students cannot graduate because of this challenge. This paper examines the process of developing self-instructional course materials at NOUN. It reflects on the challenges associated with the quantity, quality, and timely production of course materials, labelled “the hills, the wills, and the skills” obstacles. The paper concludes that there is a need for better professional development in order to provide efficient ODL delivery.

  10. Antimicrobial Effectiveness of Biobased Film Against Escherichia coli 0157:H7, Listeria monocytogenes and Salmonella typhimurium

    Directory of Open Access Journals (Sweden)

    Pornpun Theinsathid

    2011-08-01

    Full Text Available Antimicrobial packaging, an active packaging concept, can be considered challenging technology that could have a significant impact on food safety of meat and meat products. The feasibility of polylactic acid (PLA-based film was evaluated for its application as a material for antimicrobial film. A bio-based commercial polylactic acid (PLA product, Ecovio®, was used as an environmentally friendly polymer matrix. The PLA based film was incorporated with lactic acid or sodium lactate by extrusion film-blowing process. The antimicrobial activity of films against Escherichia coli O157:H7, Listeria monocytogenes and Salmonella enterica Serovar Typhimurium (S. Typhimurium were evaluated. Antimicrobial film incorporated with lactic acid packaging film was found to be highly effective in inhibiting L. monocytogenes. In contrast, no inhibitory activity was observed against E. coli O157:H7 and S. Typhimurium. This is consistent with Minimum Inhibitory Concentration (MIC studies which indicated that undissociated lactic acid was more efficient in inhibiting L. monocytogenes than enterobacteria. This preliminary study shows the potential use of bio-based film as one hurdle technology in combination with good manufacturing practices and adequate storage temperatures. The use of antimicrobial packaging may contribute to improve the safety in minimally processed foods. Further work is required to improve the mechanical properties of the material in order to meet industry requirements.

  11. Substaniation of antimicrobial dressings use in surgery

    Directory of Open Access Journals (Sweden)

    Paliy G.K.

    2014-06-01

    Full Text Available Antimicrobial materials incorporate in their structure modern antiseptics, which have the ability of dischargeng in the environment and provide death of opportunistic microorganisms. The results of the research of antimicrobial qualities of modern dressings, which include decamethoxine, chlorhexidine digluconate, furagin are shown. It was found that strains of Staphylococcus spp., Escherichia spp., Pseudomonas spp. are of high sensitivity to decamethoxin in dressing materials in comparison with textile materials, finished with chlorhexidine digluconate, furagin. The kinetics of decamethoxin release from antimicrobial materials is presented in the article. It was proven, that the release of decametoxin from antimicrobial materials in the environment occurs due to the diffusion and hydrolytic destruction of polymers in aqueous phase, which continues during 15 days.

  12. An objective approach for Burkholderia pseudomallei strain selection as challenge material for medical countermeasures efficacy testing

    Directory of Open Access Journals (Sweden)

    Kristopher E. Van Zandt

    2012-09-01

    Full Text Available Burkholderia pseudomallei is the causative agent of melioidosis, a rare disease of biodefense concern with high mortality and extreme difficulty in treatment. No human vaccines are available that protect against B. pseudomallei infection, and with the current limitations of antibiotic treatment, the development of new preventative and therapeutic interventions is crucial. Although clinical trials could be used to test the efficacy of new medical countermeasures (MCMs, the high mortality rates associated with melioidosis raises significant ethical issues concerning treating individuals with new compounds with unknown efficacies. The US Food and Drug Administration (FDA has formulated a set of guidelines for the licensure of new MCMs to treat diseases in which it would be unethical to test the efficacy of these drugs in humans. The FDA Animal Rule 21 CFR 314 calls for consistent, well-characterized B. pseudomallei strains to be used as challenge material in animal models. In order to facilitate the efficacy testing of new MCMs for melioidosis using animal models, we intend to develop a well-characterized panel of strains for use. This panel will comprise of strains that were isolated from human cases, have a low passage history, are virulent in animal models, and are well characterized phenotypically and genotypically. We have reviewed published and unpublished data on various B. pseudomallei strains to establish an objective method for selecting the strains to be included in the panel of B. pseudomallei strains with attention to five categories: animal infection models, genetic characterization, clinical and passage history, and availability of the strain to the research community. We identified 109 strains with data in at least one of the five categories, scored each strain based on the gathered data and identified 6 strains as candidate for a B. pseudomallei strain panel.

  13. IDENTIFICATION CHALLENGES IN EXAMINATION OF COMMERCIAL PLANT MATERIAL OF PSYCHOTRIA VIRIDIS.

    Science.gov (United States)

    Kowalczuk, Anna P; Łozak, Anna; Bachliński, Robert; Duszyński, Anna; Sakowska, Joanna; Zjawiony, Jordan K

    2015-01-01

    Psychoria viridis (chacruna) is a hallucinogenic plant with psychoactive properties associated with the presence of N,N-dimethyltryptamine (DMT). This species is primarily known as an ingredient of the beverage Ayahuasca, but dry leaves are also smoked by recreational users. The plant is controlled in Poland and France and its proper identification poses many challenges due to the fact that genus Psychotria is relatively large and there are other species that are easily confused with chacruna. The aim of the present work was to develop an effective authentication procedure for the dried and shredded leaves of P. viridis, to be used in comparison of chemical and botanical characteristics of its commercial products. Dried leaves of P. viridis originating from Brazil, Peru and Hawaii were purchased from Internet providers. For DMT identification, thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) methods have been elaborated, validated and applied. In order to clarify the existing differences among samples, chemometric methods have been used. Botanical features and the gas chromatography tandem mass spectrometry (GC-MS) chromatograms have been analyzed using hierarchical cluster analysis (HCA). Our studies revealed significant variety among plant material marketed as P. viridis. Grouping of samples based on their micromorphology features and GC-MS results did not correspond well with the presence of DMT. Based on our results an indisputable identification of dried specimens as P. viridis is very problematic. It is necessary to postulate changes in legislation regarding regulation of P. viridis and replace it with DMT as controlled substance. PMID:26647632

  14. Optimizing antimicrobial therapy in critically ill patients

    Directory of Open Access Journals (Sweden)

    Vitrat V

    2014-10-01

    Full Text Available Virginie Vitrat,1 Serge Hautefeuille,2 Cécile Janssen,1 David Bougon,2 Michel Sirodot,2 Leonardo Pagani1,3 1Antimicrobial Stewardship Program, Infectious Diseases Unit, 2Intensive Care Unit, Annecy-Genevois Hospital Center (CHANGE, Annecy, France; 3Infectious Diseases Unit, Bolzano Central Hospital, Bolzano, Italy Abstract: Critically ill patients with infection in the intensive care unit (ICU would certainly benefit from timely bacterial identification and effective antimicrobial treatment. Diagnostic techniques have clearly improved in the last years and allow earlier identification of bacterial strains in some cases, but these techniques are still quite expensive and not readily available in all institutions. Moreover, the ever increasing rates of resistance to antimicrobials, especially in Gram-negative pathogens, are threatening the outcome for such patients because of the lack of effective medical treatment; ICU physicians are therefore resorting to combination therapies to overcome resistance, with the direct consequence of promoting further resistance. A more appropriate use of available antimicrobials in the ICU should be pursued, and adjustments in doses and dosing through pharmacokinetics and pharmacodynamics have recently shown promising results in improving outcomes and reducing antimicrobial resistance. The aim of multidisciplinary antimicrobial stewardship programs is to improve antimicrobial prescription, and in this review we analyze the available experiences of such programs carried out in ICUs, with emphasis on results, challenges, and pitfalls. Any effective intervention aimed at improving antibiotic usage in ICUs must be brought about at the present time; otherwise, we will face the challenge of intractable infections in critically ill patients in the near future. Keywords: ICU, antimicrobial therapies, antimicrobial stewardship, pharmacokinetics, pharmacodynamics, antimicrobial resistance, early diagnosis

  15. Antimicrobial Efficiency of Edible Films in Food Industry

    Directory of Open Access Journals (Sweden)

    Dan Cristian VODNAR

    2015-12-01

    Full Text Available In this article, several applications of materials in food packaging and food safety are reviewed, including: polymers as high barrier packaging materials, natural substances as potent antimicrobial agents, and the efficiency of antimicrobial films in food industry. Active antimicrobial food packaging systems are supposed not only to passively protect food products against environmental factors, but also to inhibit or retard microbial growth on the food surface, extending the shelf life of products. Edible films can be incorporated into conventional food packaging systems with a dual purpose as an edible and antimicrobial component. Applications of antimicrobial films to fruits, vegetables and meat products have received increasing interest because films can serve as carriers for various natural antimicrobials that can maintain fresh quality, extend product shelf life and reduce the risk of pathogen growth. In the future, eco-friendly antimicrobial packaging films are promising food packaging materials because its biodegradability provides sustainable development for a modern community.In this article, several applications of materials in food packaging and food safety are reviewed, including: polymers as high barrier packaging materials, natural substances as potent antimicrobial agents, and the efficiency of antimicrobial films in food industry. Active antimicrobial food packaging systems are supposed not only to passively protect food products against environmental factors, but also to inhibit or retard microbial growth on the food surface, extending the shelf life of products. Edible films can be incorporated into conventional food packaging systems with a dual purpose as an edible and antimicrobial component. Applications of antimicrobial films to fruits, vegetables and meat products have received increasing interest because films can serve as carriers for various natural antimicrobials that can maintain fresh quality, extend product shelf

  16. [Antimicrobial peptide in dentisty. Literature review].

    Science.gov (United States)

    Sato, F Simain; Rompen, E; Heinen, E

    2009-12-01

    The use of antimicrobial substances has contributed to the development of multiple antimicrobial resistances (1), challenging the pharmaceutical industry to develop with new, innovative, and effective molecules. Discovered around 1980, molecules called natural antimicrobial peptides (AMPs) appear to hold great potential for the treatment of infections. These cationic peptides are able to stop the bacterial development and to control infections. The purpose of this review is to help improve the understanding of the way AMPs operate in the context of the development of new cures against viruses, bacteria, and mushrooms found in the human body in general and in the oral cavity in particular. PMID:20143750

  17. Antimicrobial resistance among nosocomial isolates in a teaching hospital in Goa

    OpenAIRE

    Kamat U; Ferreira AMA; Savio R; Motghare D

    2008-01-01

    Background: Emergence of polyantimicrobial resistant strains of hospital pathogens has presented a challenge in the provision of good quality in-patient care. Inappropriate use of antibiotics in the hospital is largely responsible for this catastrophe. Bacteriological surveillance of the cases of nosocomial infections is crucial for framing an evidence-based antimicrobial policy for a hospital. Materials and Methods: A prospective study was undertaken among 498 patients from medicine and s...

  18. Prospects and Challenges in Application of Radiation for Treating Exhaust Gases. Working Material

    International Nuclear Information System (INIS)

    Strategies to tackle environmental pollution are receiving increasing attention throughout the world in recent years. Besides improving conventional technologies, new ones are still being developed. Among them technologies for multipollutant control are of great interest. The electron beam flue gas treatment technology (EBFGT) is one of the most promising technologies for simultaneous removal of multiple pollutants. The process was originally invented in Japan in 1970's. Later on, the process was investigated at the pilot scale plants in USA, Germany, Japan, China, Republic of Korea and Poland. This resulted in construction of commercial scale installation in Poland treating approximately 270,000 Nm3/h of flue gases with the efficiency reaching up to 95% for SOx and up to 70% for NOx. The by-product of the process is a high quality fertilizer. The advantages of the technology has been clearly demonstrated both from technological and economical points of view. Recently an important research program has been realized in Maritza East 2 pilot plant in Bulgaria and another one considering application of electron beam technology for treatment of flue gas from heavy oils burning has been undertaken in Saudi Arabia. Apart of the research programs, new industrial plants are concerned. Another implementation of the EBFGT technology of industrial scale is the plant that is being constructed in Jingfeng Power Plant in Beijing (China) and should be put into operation soon. Another commercial plant (Sviloza Thermal Power plant in Svishtov, Bulgaria) is in the design phase. The IAEA has been supporting the activities by establishing the Technical Cooperation Projects (e.g. POL/8/014, BUL/8/014) and through organizing Advisory Group Meetings, Consultants Meeting, Symposium, Technical Meetings, and Coordinated Research Projects. The Technical Meeting on “Prospects and Challenges in Application of Radiation for Treating Exhaust Gases” held on 14-18 May 2007 in Warsaw, Poland was

  19. Antimicrobial Properties of a Novel Silver-Silica Nanocomposite Material▿

    Science.gov (United States)

    Egger, Salome; Lehmann, Rainer P.; Height, Murray J.; Loessner, Martin J.; Schuppler, Markus

    2009-01-01

    Nanotechnology enables development and production of novel silver-based composite materials. We used in vitro tests to demonstrate the antimicrobial activity of a silver-silica nanocomposite compared to the activities of conventional materials, such as silver nitrate and silver zeolite. A silver-silica-containing polystyrene material was manufactured and shown to possess strong antimicrobial properties. PMID:19270121

  20. Antimicrobial Properties of a Novel Silver-Silica Nanocomposite Material▿

    OpenAIRE

    Egger, Salome; Lehmann, Rainer P.; Height, Murray J.; Loessner, Martin J; Schuppler, Markus

    2009-01-01

    Nanotechnology enables development and production of novel silver-based composite materials. We used in vitro tests to demonstrate the antimicrobial activity of a silver-silica nanocomposite compared to the activities of conventional materials, such as silver nitrate and silver zeolite. A silver-silica-containing polystyrene material was manufactured and shown to possess strong antimicrobial properties.

  1. Antimicrobial activities of squalamine mimics.

    Science.gov (United States)

    Kikuchi, K; Bernard, E M; Sadownik, A; Regen, S L; Armstrong, D

    1997-07-01

    We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus faecium, and fungi. Some had little or no hemolytic activity. The hydrophobicity of the sterol backbone and the length and the cationic charge of the side chains appeared to be critical determinants of activity. One of the squalamine mimics, SM-7, was bactericidal against Escherichia coli, Pseudomonas aeruginosa, and S. aureus; its activity was decreased by divalent or monovalent cations and by bovine serum albumin. Subinhibitory concentrations of SM-7 markedly enhanced the antimicrobial activity of rifampin against gram-negative rods. These results suggest that the compounds may disrupt an outer membrane of gram-negative rods. Squalamine mimics are a new class of broad-spectrum antimicrobial agents. The antagonism of their activity by serum and albumin and their hemolytic properties may limit their use as systemic agents. The squalamine mimics, because of their potencies, broad spectra of antimicrobial activity, and potential for systemic toxicity, appear to be good candidates for development as topical antimicrobial agents. PMID:9210661

  2. Opportunities and challenges of 2D magnetic van der Waals materials: magnetic graphene?

    Science.gov (United States)

    Park, Je-Geun

    2016-08-01

    There has been a huge increase of interests in two-dimensional van der Waals materials over the past ten years or so with the conspicuous absence of one particular class of materials: magnetic van der Waals systems. In this Viewpoint, we point it out and illustrate how we might be able to benefit from exploring these so-far neglected materials.

  3. Materials to deliver the promise of fusion power - progress and challenges

    Science.gov (United States)

    Bloom, E. E.; Zinkle, S. J.; Wiffen, F. W.

    2004-08-01

    High-performance reduced-activation materials are crucial for fulfillment of the promise of fusion to provide safe, economical, and environmentally acceptable energy. Three reduced activation structural materials have emerged as promising candidates, based on 8-9Cr ferritic/martensitic steels, V-Cr-Ti alloys, and SiC/SiC composites. Due to advances in understanding how to control and engineer the nanoscale phase stability required for harsh neutron irradiation environments, these reduced activation materials have unirradiated properties that are superior to commercially available analogs. Perhaps the most important accomplishment to date from fusion materials research is the radiation effects knowledge base. Models of radiation effects and supporting experiments highlight the critical role of helium production on the microstructural stability and lifetime of irradiated materials. The proposed International Fusion Materials Irradiation Facility (IFMIF) would fill a critical need for fusion materials development.

  4. Notions of materiality and linearity: the challenges of marketing the Hadrian’s Wall place ‘product’

    OpenAIRE

    Gary Warnaby; Dominic Medway; David Bennison

    2010-01-01

    This paper provides a detailed examination of the marketing of Hadrian’s Wall in northern England. The focus of this case is built around two themes which encapsulate the complexities and challenges of marketing such a place entity: (1) the Wall’s existence as an historical monument of diminished materiality, and (2) its linearity and spatial diffuseness. These themes emphasise the fact that marketing Hadrian’s Wall is different from usual place-marketing activity, which is typically focused ...

  5. Antimicrobial Efficiency of Edible Films in Food Industry

    OpenAIRE

    Dan Cristian VODNAR; Pop, Oana Lelia; Francisc Vasile DULF; Socaciu, Carmen

    2015-01-01

    In this article, several applications of materials in food packaging and food safety are reviewed, including: polymers as high barrier packaging materials, natural substances as potent antimicrobial agents, and the efficiency of antimicrobial films in food industry. Active antimicrobial food packaging systems are supposed not only to passively protect food products against environmental factors, but also to inhibit or retard microbial growth on the food surface, extending the shelf life of pr...

  6. Geometry generation challenges for modelling and analysis of micro-structured materials

    Science.gov (United States)

    McMillan, A. J.

    2015-02-01

    Engineers evaluating the performance of a component at the design stage will typically convert Computer Aided Design (CAD) geometry into a Finite Element model, and run a Finite Element Analysis (FEA) to determine deformations and stress levels as a result of applied loads or displacements. The analysis results would then be interpreted by comparing them with the required duty of the component. For metallic components, homogeneous and isotropic material properties are generally assumed - "macro-scale" modelling. For components to be manufactured from composite materials, models may represent heterogeneity at the ply level, and orthotropic material properties applied with appropriate directionality. This ply-level modelling is often termed "meso-scale" modelling. Engineering interpretation of failure in materials is often based on empirical understanding of experimental data. This approach is generally robust: safety critical components would always be subject to validation by means of a suitable programme of testing. The aspect that is missing is the opportunity to improve understanding of the material performance by investigating the material performance at the "micro-scale". This paper describes computational algorithms for generating random geometries exhibiting similar characteristics to those seen at the "micro-scale" in real materials, and the use of these to predict the influence of the "micro-scale" structure on the "macro-scale" material performance.

  7. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... More in Antimicrobial Resistance National Antimicrobial Resistance Monitoring System About NARMS Bacteria (NARMS) NARMS at Work Reports ... Emergency Preparedness International Programs News & Events Training & Continuing Education Inspections & Compliance Federal, State & Local Officials Consumers Health ...

  8. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... emerges and proliferates among bacteria. Over time, the use of antimicrobial drugs will result in the development ... Data Recent Publications NARMS Meetings NARMS Resources Judicious Use of Antimicrobials Resources for You Windows Media Player ...

  9. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... Accordingly, efforts are underway in both veterinary and human medicine to preserve the ... Antimicrobials Resources for You Windows ...

  10. Optimizing antimicrobial therapy in critically ill patients.

    Science.gov (United States)

    Vitrat, Virginie; Hautefeuille, Serge; Janssen, Cécile; Bougon, David; Sirodot, Michel; Pagani, Leonardo

    2014-01-01

    Critically ill patients with infection in the intensive care unit (ICU) would certainly benefit from timely bacterial identification and effective antimicrobial treatment. Diagnostic techniques have clearly improved in the last years and allow earlier identification of bacterial strains in some cases, but these techniques are still quite expensive and not readily available in all institutions. Moreover, the ever increasing rates of resistance to antimicrobials, especially in Gram-negative pathogens, are threatening the outcome for such patients because of the lack of effective medical treatment; ICU physicians are therefore resorting to combination therapies to overcome resistance, with the direct consequence of promoting further resistance. A more appropriate use of available antimicrobials in the ICU should be pursued, and adjustments in doses and dosing through pharmacokinetics and pharmacodynamics have recently shown promising results in improving outcomes and reducing antimicrobial resistance. The aim of multidisciplinary antimicrobial stewardship programs is to improve antimicrobial prescription, and in this review we analyze the available experiences of such programs carried out in ICUs, with emphasis on results, challenges, and pitfalls. Any effective intervention aimed at improving antibiotic usage in ICUs must be brought about at the present time; otherwise, we will face the challenge of intractable infections in critically ill patients in the near future. PMID:25349478

  11. Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens: a co-culture study in vitro.

    Science.gov (United States)

    Zhao, Bingran; van der Mei, Henny C; Rustema-Abbing, Minie; Busscher, Henk J; Ren, Yijin

    2015-12-01

    Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity. PMID:26674427

  12. Antimicrobial Effects of Honey on Bacillus Cereus

    OpenAIRE

    This paper should be cited as: Javadzadeh M, Najafi M, Rezaei M, Dastoor M, Behzadi AS, Amiri A . [ Antimicrobial Effects of Honey on Bacillus Cereus ]. MLJ. 201 4 ; 8 ( 2 ): 55 - 61 [Article in Persian] Javadzadeh, M. (MSc; M Najafi; Rezaei, M. (MSc; Dastoor, M. (BSc; Behzadi, AS. (MSc; Amiri, A. (MSc

    2014-01-01

    Background and Objective: Honey is a healthy and nutritious food that has been used for a long time as a treatment for different diseases. One of the applied properties of honey is its antimicrobial effect, which differs between different types of honey due to variation of phenolic and antioxidant compositions. This study aimed to assess antimicrobial effect of honey on Bacillus cereus, considering its chemical properties. Material and Methods: Three samples of honey (A1 and A2 of Khorasan Ra...

  13. International safeguards challenges in the 1990's for controlling nuclear material

    International Nuclear Information System (INIS)

    The world in which we live during the 1990's is certainly more complex than it was before the breakup of the Soviet Union. We all have major challenges before us. Faced with shrinking budgets and competing priorities, we must keep nuclear nonproliferation in the foreground. It will require all of us in the international community to work together to make our plans to assure nonproliferation a reality, and to counter the increasing threat of nuclear proliferation through the decade of the 1990's and well into the 21st Century. (J.P.N.)

  14. Challenges of selecting materials for the process of biomass gasification in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Boukis, N.; Habicht, W.; Hauer, E.; Dinjus, E. [Karlsruher Institut fuer Technologie (KIT), Karlsruhe (Germany). Inst. fuer Technische Chemie

    2010-07-01

    A new process for the gasification of wet biomass is the reaction in supercritical water. The product is a combustible gas, rich in hydrogen with a high calorific value. The reaction is performed under high temperatures - up to 700 C - and pressures up to 30 MPa. The combination of these physical conditions and the corrosive environment is very demanding for the construction materials of the reactor. Only few alloys exhibit the required mechanical properties, especially the mechanical strength at temperatures higher than 600 C. Ni-Base alloys like alloy 625 can be applied up to a temperature of 700 C and are common materials for application under supercritical water conditions. During gasification experiments with corn silage and other biomasses, corrosion of the reactor material alloy 625 appears. The gasification of an aqueous methanol solution in supercritical water at temperatures up to 600 C and 25 - 30 MPa pressure results in an product gas rich in hydrogen, carbon dioxide and some methane. Alloy 625 shows very low corrosion rates in this environment. It is obvious that the heteroatoms and salts present in biomass cause corrosion of the reactor material. (orig.)

  15. Trends and challenges in the mechanics of complex materials: a view

    Science.gov (United States)

    Mariano, Paolo Maria

    2016-01-01

    This article introduces the collection of papers in this issue of the Philosophical Transactions of the Royal Society A and offers a perspective view on the description of the mechanics of material characterized by a prominent influence of small-scale phenomena on the gross mechanical behaviour. PMID:27002073

  16. Next nuclear challenge - how do we dispose of the excess nuclear materials?

    International Nuclear Information System (INIS)

    The ''Cold War'' was not fought only by soldiers but by scientists and engineers in Laboratories and plants located throughout the world. With the fall of the Berlin Wall, the ''Cold War'' was effectively over, but the weapons of nuclear war remained. Following signing of START 2 (Strategic Arms Reduction Treaty) in 1993, up to 100 tonnes of weapons usable plutonium is expected to be declared excess by the Super Powers. Steps must be taken to address the proliferation risks associated with this plutonium. Again the scientist and engineers, who were the ''Cold War'' warriors, are being asked to develop methods to disposition this plutonium such that it can never again be used for weapons. Will we burn the plutonium in reactors or immobilize the plutonium either in a glass or ceramic matrix? Interesting challenges face chemists and chemical engineers developing immobilization techniques to render the plutonium both environmentally benign, and proliferation resistant

  17. NATO Advanced Study Institute on Materials Issues for Generation IV Systems : Status, Open Questions and Challenges

    CERN Document Server

    Gorse, Dominique; Mazière, Dominique; Pontikis, Vassilis

    2008-01-01

    Global warming, shortage of low-cost oil resources and the increasing demand for energy are currently controlling the world's economic expansion while often opposing desires for sustainable and peaceful development. In this context, atomic energy satisfactorily fulfills the criteria of low carbon gas production and high overall yield. However, in the absence of industrial fast-breeders the use of nuclear fuel is not optimal, and the production of high activity waste materials is at a maximum. These are the principal reasons for the development of a new, fourth generation of nuclear reactors, minimizing the undesirable side-effects of current nuclear energy production technology while increasing yields by increasing operation temperatures and opening the way for the industrial production of hydrogen through the decomposition of water. The construction and use of such reactors is hindered by several factors, including performance limitations of known structural materials, particularly if the life of the project...

  18. ENERGY EFFICIENCY CHALLENGES ADDRESSED THROUGH THE USE OF ADVANCED REFRACTORY CERAMIC MATERIALS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL

    2014-01-01

    Refractory ceramics can play a critical role in improving the energy efficiency of traditional industrial processes through increased furnace efficiency brought about by the employment of novel refractory systems and techniques. Examples of advances in refractory materials related to aluminum, gasification, glass, and lime are highlighted. Energy savings are realized based on reduction of chemical reactions, elimination of mechanical degradation caused by the service environment, reduction of temperature limitations of materials, and elimination of costly installation and repair needs. Key results of projects resulting from US Department of Energy (DOE) funded research programs are discussed with emphasis on applicability of these results to high temperature furnace applications and needed research directions for the future.

  19. Textiles as Tangible Working Materials in Participatory Design Processes: Potentials and Challenges

    DEFF Research Database (Denmark)

    Heimdal, Elisabeth Jacobsen; Rosenqvist, Tanja Schultz

    Participatory design (PD) methods are currently of little use in the textile industry, even though the need for multiple stakeholder involvement in the industry is growing. In this paper, we argue that PD represents a potential for innovation in the textile industry, due to PD’s collaborative...... nature facilitating dialogue between different stakeholders and its ability to move stakeholder participation to the early stages of the design process. We have explored PD tools in a design process engaging architects and textile designers in designing textile products for Danish hospitals. From this we...... have realized a potential in dividing the materials into three types with different attributes, which should consequently be staged differently in a PD process. We have thereby seen that exploring PD in a textile design process improves the understanding of the role of tangible working materials in PD...

  20. Electrode materials: a challenge for the exploitation of protonic solid oxide fuel cells

    Directory of Open Access Journals (Sweden)

    Emiliana Fabbri, Daniele Pergolesi and Enrico Traversa

    2010-01-01

    Full Text Available High temperature proton conductor (HTPC oxides are attracting extensive attention as electrolyte materials alternative to oxygen-ion conductors for use in solid oxide fuel cells (SOFCs operating at intermediate temperatures (400–700 °C. The need to lower the operating temperature is dictated by cost reduction for SOFC pervasive use. The major stake for the deployment of this technology is the availability of electrodes able to limit polarization losses at the reduced operation temperature. This review aims to comprehensively describe the state-of-the-art anode and cathode materials that have so far been tested with HTPC oxide electrolytes, offering guidelines and possible strategies to speed up the development of protonic SOFCs.

  1. Antimicrobial activities of squalamine mimics.

    OpenAIRE

    Kikuchi, K.; Bernard, E M; Sadownik, A; Regen, S L; Armstrong, D

    1997-01-01

    We investigated the antimicrobial properties of compounds with structural features that were designed to mimic those of squalamine, an antibiotic isolated from the stomach of the dogfish shark. The mimics, like squalamine, are sterol-polyamine conjugates. Unlike squalamine, the mimics were simple to prepare, at high yield, from readily available starting materials. Several squalamine mimics showed activity against gram-negative rods, gram-positive cocci including methicillin-resistant Staphyl...

  2. Fashion and function: challenges faced by textiles incorporated with phase change materials

    OpenAIRE

    Gao, Chuansi

    2014-01-01

    Designers focus on fashion and appearance, whereas safety and protection engineers and physiologists emphasize functions in terms of developing functional and protective clothing. Phase change materials (PCMs) have been used in textiles and clothing to achieve cooling or warming function. The objective of this paper was to compare effectiveness of PCM cooling or warming determined by critical factors. Cooling or warming effectiveness and duration were directly dependent on physical activity l...

  3. High purity materials as targets for radioisotope production: Needs and challenges

    Indian Academy of Sciences (India)

    V Shivarudrappa; K V Vimalnath

    2005-07-01

    Radionuclides have become powerful and indispensable tools in many endeavours of human activities, most importantly in medicine, industry, biology and agriculture, apart from R&D activities. Ready availability of radionuclides in suitable radiochemical form, its facile detection and elegant tracer concepts are responsible for their unprecedented use. Application of radioisotopes in medicine has given birth to a new branch, viz. nuclear medicine, wherein radioisotopes are used extensively in the diagnosis and treatment of variety of diseases including cancer. Artificial transmutation of an element employing thermal neutrons in a reactor or high energy particle accelerators (cyclotrons) are the routes of radioisotope production world over. Availability of high purity target materials, natural or enriched, are crucial for any successful radioisotope programme. Selection of stable nuclides in suitable chemical form as targets with desired isotopic and chemical purity are among the important considerations in radioisotope production. Mostly the oxide, carbonate or the metal itself are the preferred target forms for neutron activation in a research reactor. Chemical impurities, particularly from the elements of the same group, put a limitation on the purity of the final radioisotope product. Whereas the isotopic impurities result in the production of undesirable radionuclidic impurities, which affect their effective utilization. Isotope Group, BARC, is in the forefront of radioisotope production and supply in the country, meeting demands for gamut of radioisotope applications indigenously for over four decades now. Radioisotopes such as 131I, 99Mo, 32P, 51Cr, 153Sm, 82Br, 203Hg, 198Au etc are produced in TBq quantities every month and supplied to several users and to Board of Radiation and Isotope Technology (BRIT). Such a large production programme puts a huge demand on the reliable sources of availability of high purity target materials which are at present mostly met

  4. Fundamentals of SO2 depolarized water electrolysis and challenges of materials used

    OpenAIRE

    Lokkiluoto, Anu

    2013-01-01

    Sulfur dioxide depolarized water electrolysis (SDE) produces sulfuric acid and hydrogen. Due to its lower cell voltage, the process requires far less electricity than traditional water electrolysis. When SO2 is obtained from flash smelting, sulfides roasting, sulfur combustion, or any other similar operation, SDE is a part of the OutotecR open cycle process. In the present work, materials to be used in SDE were studied together with the fundamentals of the process. Data on the co-productio...

  5. The Three Bacterial Lines of Defense against Antimicrobial Agents

    OpenAIRE

    Gang Zhou; Qing-Shan Shi; Xiao-Mo Huang; Xiao-Bao Xie

    2015-01-01

    Antimicrobial agents target a range of extra- and/or intracellular loci from cytoplasmic wall to membrane, intracellular enzymes and genetic materials. Meanwhile, many resistance mechanisms employed by bacteria to counter antimicrobial agents have been found and reported in the past decades. Based on their spatially distinct sites of action and distribution of location, antimicrobial resistance mechanisms of bacteria were categorized into three groups, coined the three lines of bacterial defe...

  6. Multiaxial and Thermomechanical Fatigue of Materials: A Historical Perspective and Some Future Challenges

    Science.gov (United States)

    Kalluri, Sreeramesh

    2013-01-01

    Structural materials used in engineering applications routinely subjected to repetitive mechanical loads in multiple directions under non-isothermal conditions. Over past few decades, several multiaxial fatigue life estimation models (stress- and strain-based) developed for isothermal conditions. Historically, numerous fatigue life prediction models also developed for thermomechanical fatigue (TMF) life prediction, predominantly for uniaxial mechanical loading conditions. Realistic structural components encounter multiaxial loads and non-isothermal loading conditions, which increase potential for interaction of damage modes. A need exists for mechanical testing and development verification of life prediction models under such conditions.

  7. Clinical impact of antimicrobial resistance in animals.

    Science.gov (United States)

    Vaarten, J

    2012-04-01

    It is almost impossible to imagine veterinary medicine today without the use of antimicrobials. Shortly after their discovery, antimicrobials found their way into the veterinary world. They have brought many benefits for the health and welfare of both animals and people, such as the lessening of pain and suffering, reduction in shedding of (zoonotic) bacteria and the containment of potentially large-scale epidemics. Indirectly, they also contribute to food security, protection of livelihoods and animal resources, and poverty alleviation. Given the broad range of animal species under veterinary care and the enormous variety of infectious agents, a complete range of antimicrobials is needed in veterinary medicine. Losing products, either through the occurrence of resistance or through a prohibition on their use, will have serious consequences for the health and welfare of all animals. It will also seriously affect people who depend on these animals. It is a great challenge to everyone involved to stop the growing trend of antimicrobial resistance and to safeguard the effectiveness of antimicrobials for the future. Transparent and responsible use of antimicrobials, together with continuous monitoring and surveillance of the occurrence of resistance, are key elements of any strategy. The current situation also urges us to re-think unsustainable practices and to work on the development of alternatives, in the interests of the health and welfare of both animals and people. PMID:22849278

  8. Consultancy on 'Implementing thorium in nuclear reactor fuel cycles: Potential benefits and challenges'. Working material

    International Nuclear Information System (INIS)

    The objective of this consultancy (CS) was to bring together experts from the MS to discuss R and D developments in the study of thorium fuel cycles and to identify MS needs in support of national activities in this area. The CS was also meant to define an appropriate IAEA response to these needs, e.g., recommend topics for information exchange and collaborative R andD activities to be implemented in a planned CRP. Presentations were made on past thorium-fuel-cycle activities at IAEA, and on R and D activities in Canada, India and the Russian Federation. Following these presentations and further discussions on topics of importance in thorium based fuel cycles, the CS arrived at a proposal for a new CRP entitled 'The Comparative Assessment of the Fuel-Cycle Aspects of Various Thorium-Based Reactor Concepts'. The CRP should be based on a unified systematic approach for a comparative assessment of the various designs for utilizing thorium fuel, and their potential benefits as compared to uranium-plutonium fuelled systems. The CS recommended a list of fuel-cycle performance parameters to be considered in the CRP for the above purpose. Finally, the CS proposed a plan of action for the initiation of the CRP by the Scientific Secretary. The meeting was very much appreciated by the participants and was a good opportunity to exchange information on research activities and methods, and discuss potential challenges to and solutions for the implementation of thorium fuel cycles. (author)

  9. Next nuclear challenge - how do we dispose of the excess nuclear materials?

    Energy Technology Data Exchange (ETDEWEB)

    Gray, L W

    1997-04-03

    The ''Cold War'' was not fought only by soldiers but by scientists and engineers in Laboratories and plants located throughout the world. With the fall of the Berlin Wall, the ''Cold War'' was effectively over, but the weapons of nuclear war remained. Following signing of START 2 (Strategic Arms Reduction Treaty) in 1993, up to 100 tonnes of weapons usable plutonium is expected to be declared excess by the Super Powers. Steps must be taken to address the proliferation risks associated with this plutonium. Again the scientist and engineers, who were the ''Cold War'' warriors, are being asked to develop methods to disposition this plutonium such that it can never again be used for weapons. Will we burn the plutonium in reactors or immobilize the plutonium either in a glass or ceramic matrix? Interesting challenges face chemists and chemical engineers developing immobilization techniques to render the plutonium both environmentally benign, and proliferation resistant.

  10. New Catalytic Materials for Meeting the Challenge of Clean Gasoline & Diesel Fuel Production

    Institute of Scientific and Technical Information of China (English)

    Zong Baoning; Min Enze; He Mingyuan; Li Dadong

    2000-01-01

    New catalytic materials, which may bring important improvement or technical breakthrough to the petroleum refining technology for producing reformulated gasoline and low sulfur and aromatics diesel fuel, are discussed. For the purpose of producing high octane number gasoline and light olefins for etherification and alkylation processes, major improvements are achieved by the use of high reactivity-stability MFI type ZRP and low cost beta zeolites. A solid P-W heteropolyacid supported on SiO2 for replacing currently used HF and H2SO4 in alkylation process of isobutane with butenes, is under the pilot trial. For the production of low sulfur and aromatics diesel fuel, high surface area supported metallic nitrides are under extensive studies.

  11. Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites

    International Nuclear Information System (INIS)

    There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. - Highlights: • A possible approach for fabrication of the

  12. Antimicrobial hyperbranched poly(ester amide)/polyaniline nanofiber modified montmorillonite nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Sujata [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India); Bharali, Pranjal; Konwar, B.K. [Department of Molecular Biology and Biotechnology, Tezpur University, Tezpur 784028 (India); Karak, Niranjan, E-mail: karakniranjan@yahoo.com [Advanced Polymer and Nanomaterial Laboratory, Department of Chemical Sciences, Tezpur University, Tezpur 784028 (India)

    2014-02-01

    There has been growing interest in the use of nanomaterials featuring potent of antimicrobial activity in the biomedical domain. It still remains a challenge for the researchers to develop an efficient nanocomposite possessing antimicrobial efficacy against broad spectrum microbes including bacteria, fungi as well as algal consortium, posing serious challenges for the human survival. In addressing the above problem, we report the fabrication of bio-based hyperbranched poly(ester amide) (HBPEA)/polyaniline nanofiber modified montmorillonite (MMT) nanocomposites by an ex-situ polymerization technique at varied weight percentages (1, 2.5, 5 wt.%) of the modified MMT (nanohybrid). The Fourier transform infrared spectroscopy confirmed the structural changes upon interaction of the nanohybrid with HBPEA. A probable mechanism is proposed for the formation of nanocomposites with partially exfoliated nanoplatelet structure, which was further confirmed from the high resolution transmission electron microscopic analyses. The prepared nanocomposites exhibited potent efficacy against gram positive bacteria like Bacillus subtilis and Staphylococcus aureus as compared to the gram negative ones like Pseudomonas aeruginosa and Escherichia coli. The nanocomposites showed significant antifungal activity against Aspergillus niger, Fusarium oxysporum and Coleotricum capcii and antialgal activity against algal consortium comprising of Chlorella, Hormidium and Cladophorella species. The formation of thermosetting nanocomposites resulted in the acceptable improvement of desired physico-chemical and mechanical properties including thermostability. Thus pronounced antimicrobial activity of the nanocomposites against a spectrum of bacterial and fungal strains as well as a consortium of algal species along with other desired performance vouched them as potent antimicrobial materials in the realm of health and biomedical industry. - Highlights: • A possible approach for fabrication of the

  13. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... clinician's efforts to select the appropriate antimicrobial for treatment. Accordingly, efforts are underway in both veterinary and ... Consumers Health Professionals Science & ...

  14. Possibilities and Challenges of Scanning Hard X-ray Spectro-microscopy Techniques in Material Sciences

    Directory of Open Access Journals (Sweden)

    Andrea Somogyi

    2015-06-01

    Full Text Available Scanning hard X-ray spectro-microscopic imaging opens unprecedented possibilities in the study of inhomogeneous samples at different length-scales. It gives insight into the spatial variation of the major and minor components, impurities and dopants of the sample, and their chemical and electronic states at micro- and nano-meter scales. Measuring, modelling and understanding novel properties of laterally confined structures are now attainable. The large penetration depth of hard X-rays (several keV to several 10 keV beam energy makes the study of layered and buried structures possible also in in situ and in operando conditions. The combination of different X-ray analytical techniques complementary to scanning spectro-microscopy, such as X-ray diffraction, X-ray excited optical luminescence, secondary ion mass spectrometry (SIMS and nano-SIMS, provides access to optical characteristics and strain and stress distributions. Complex sample environments (temperature, pressure, controlled atmosphere/vacuum, chemical environment are also possible and were demonstrated, and allow as well the combination with other analysis techniques (Raman spectroscopy, infrared imaging, mechanical tensile devices, etc. on precisely the very same area of the sample. The use of the coherence properties of X-rays from synchrotron sources is triggering emerging experimental imaging approaches with nanometer lateral resolution. New fast analytical possibilities pave the way towards statistically significant studies at multi- length-scales and three dimensional tomographic investigations. This paper gives an overview of these techniques and their recent achievements in the field of material sciences.

  15. Development of chitosan-based antimicrobial leather coatings.

    Science.gov (United States)

    Fernandes, Isabel P; Amaral, Joana S; Pinto, Vera; Ferreira, Maria José; Barreiro, Maria Filomena

    2013-10-15

    The development of antimicrobial coatings for footwear components is of great interest both from industry and consumer's point of view. In this work, antimicrobial leather materials were developed taking advantage of chitosan intrinsic antimicrobial activity and film forming capacity. Considering the specificities of the leather tanning industry, different coating technologies, namely drum, calender and spray, were tested, being the best results achieved with the drum. This last approach was further investigated to assess the effect of chitosan content, type of solubilizing acid, and impregnation time on the achieved antimicrobial capacity. Considering chitosan price (economic reasons) and the obtained results (antimicrobial activity and coating effectiveness, as inspected by SEM), the impregnation in the drum using a chitosan content of 1% (w/v) in a formic acid solution during 2h, is proposed as the best option for obtaining leather with antimicrobial capacity. PMID:23987468

  16. Prophylactic antimicrobial practice in the Orthopaedic wards of RIPAS Hospital.

    OpenAIRE

    Lah Kheng CHUA

    2012-01-01

    Introduction: Surgical site infections (SSI) are common healthcare associated infections (HAI) that is associated with increased morbidity and cost. Antimicrobial prophylaxis is effective when used appropriately. This study assesses the prophylactic antimicrobial prescribing and practice in the orthopaedic wards based on the Scottish Intercollegiate Guidelines Network (SIGN) guideline on antibiotic prophylaxis in surgery. Materials and Methods: Patients admitted to the Orthopaedics wards over...

  17. Packaging Technologies for 500 C SiC Electronics and Sensors: Challenges in Material Science and Technology

    Science.gov (United States)

    Chen, Liang-Yu; Neudeck, Philip G.; Behelm, Glenn M.; Spry, David J.; Meredith, Roger D.; Hunter, Gary W.

    2015-01-01

    This paper presents ceramic substrates and thick-film metallization based packaging technologies in development for 500C silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chip-level packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550C. The 96 alumina packaging system composed of chip-level packages and PCBs has been successfully tested with high temperature SiC discrete transistor devices at 500C for over 10,000 hours. In addition to tests in a laboratory environment, a SiC junction field-effect-transistor (JFET) with a packaging system composed of a 96 alumina chip-level package and an alumina printed circuit board was tested on low earth orbit for eighteen months via a NASA International Space Station experiment. In addition to packaging systems for electronics, a spark-plug type sensor package based on this high temperature interconnection system for high temperature SiC capacitive pressure sensors was also developed and tested. In order to further significantly improve the performance of packaging system for higher packaging density, higher operation frequency, power rating, and even higher temperatures, some fundamental material challenges must be addressed. This presentation will discuss previous development and some of the challenges in material science (technology) to improve high temperature dielectrics for packaging applications.

  18. Antimicrobial coatings — obtaining and characterization

    Indian Academy of Sciences (India)

    Cornelia Guran; Alexandra Pica; Denisa Ficai; Anton Ficai; Cezar Comanescu

    2013-04-01

    In this paper, we present inorganic–organic hybrid coatings with polymer matrix (water soluble) that contain silver nanoparticles (AgNPs). The structure and morphology of coating materials were determined by infrared spectroscopy (FT–IR) and scanning electron microscopy (SEM). Therefore, the antimicrobial activities and mechanisms of coatings for several pathogenic bacteria (Bacilius cereus and Staphylococcus aureus) were investigated. It was demonstrated that the obtained material with silver nanoparticles keep their antimicrobial effect even if they are subjected to several cycles of washing with water and detergent.

  19. Biodegradable polylactic acid polymer with nisin for use in antimicrobial food packaging

    Science.gov (United States)

    Biodegradable polylactic acid (PLA) polymer was evaluated for its application as a material for antimicrobial food packaging. PLA films were incorporated with nisin to provide slow release of the encapsulated antimicrobial for control of foodborne pathogens. Antimicrobial activity of PLA/nisin films...

  20. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) Chinese Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) ... by Product Area Product Areas back Food Drugs Medical Devices Radiation-Emitting Products Vaccines, Blood & Biologics Animal & ...

  1. Antimicrobial Peptides in 2014

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2015-03-01

    Full Text Available This article highlights new members, novel mechanisms of action, new functions, and interesting applications of antimicrobial peptides reported in 2014. As of December 2014, over 100 new peptides were registered into the Antimicrobial Peptide Database, increasing the total number of entries to 2493. Unique antimicrobial peptides have been identified from marine bacteria, fungi, and plants. Environmental conditions clearly influence peptide activity or function. Human α-defensin HD-6 is only antimicrobial under reduced conditions. The pH-dependent oligomerization of human cathelicidin LL-37 is linked to double-stranded RNA delivery to endosomes, where the acidic pH triggers the dissociation of the peptide aggregate to release its cargo. Proline-rich peptides, previously known to bind to heat shock proteins, are shown to inhibit protein synthesis. A model antimicrobial peptide is demonstrated to have multiple hits on bacteria, including surface protein delocalization. While cell surface modification to decrease cationic peptide binding is a recognized resistance mechanism for pathogenic bacteria, it is also used as a survival strategy for commensal bacteria. The year 2014 also witnessed continued efforts in exploiting potential applications of antimicrobial peptides. We highlight 3D structure-based design of peptide antimicrobials and vaccines, surface coating, delivery systems, and microbial detection devices involving antimicrobial peptides. The 2014 results also support that combination therapy is preferred over monotherapy in treating biofilms.

  2. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts to select the appropriate antimicrobial for treatment. Accordingly, efforts are underway in both veterinary and human medicine to preserve the effectiveness of these drugs. ...

  3. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) Chinese Translation - Animation of Antimicrobial Resistance (WMV - 19.2MB) ... FEAR Act Site Map Transparency Website Policies U.S. Food and Drug Administration 10903 New Hampshire Avenue Silver ...

  4. Development of antimicrobial optimum glass ionomer

    International Nuclear Information System (INIS)

    The use of glass ionomer for restorations in dentistry for lower income population is a well established practice in public clinics of Brazil. However the average price of this kind of material and its low durability still have a negative impact on public health for being imported and frequently replaced it becomes expensive for the manufacturers and for public agencies. In glass ionomer the main antimicrobial agent is fluoride, which is released gradually. The material used for filling provides an average life of five years and its durability can be increased if the ionomer contains other oligodynamic elements. It was formulated, merged a new optimized glass ionomer which was characterized by X-ray diffraction, ion measurement and antimicrobial activity. This new product showed promising results, that pointed structural stability an increase of antimicrobial efficiency. (author)

  5. Descriptors for antimicrobial peptides

    DEFF Research Database (Denmark)

    Jenssen, Håvard

    2011-01-01

    Introduction: A frightening increase in the number of isolated multidrug resistant bacterial strains linked to the decline in novel antimicrobial drugs entering the market is a great cause for concern. Cationic antimicrobial peptides (AMPs) have lately been introduced as a potential new class of...... antimicrobial drugs, and computational methods utilizing molecular descriptors can significantly accelerate the development of new peptide drug candidates. Areas covered: This paper gives a broad overview of peptide and amino-acid scale descriptors available for AMP modeling and highlights which of these are...

  6. ANTIMICROBIAL ACTIVITIES OF 1,3,4-OXADIAZOLE : A REVIEW

    Directory of Open Access Journals (Sweden)

    Bachwani Mukesh

    2011-06-01

    Full Text Available 1, 3, 4-Oxadiazole is a highly privileged structure the derivatives of which exhibit a wide range of biological activities including antibacterial, antitubercular, vasodialatory, antifungal, cytotoxic, anti-inflammatory and analgesic, hypolipidemic, anticancer and ulcerogenic activities. Resistance to number of antimicrobial agents among a variety of clinically significant species of bacteria is becoming increasingly important global problem. The search for new antimicrobial agents will consequently always remain as an important and challenging task for medicinal chemists. This Review has basic information about 1,3,4-oxadiazole and its antimicrobial activity work for further development in this field.

  7. Nanoliposomes containing Eucalyptus citriodora as antibiotic with specific antimicrobial activity.

    Science.gov (United States)

    Lin, Lin; Cui, Haiying; Zhou, Hui; Zhang, Xuejing; Bortolini, Christian; Chen, Menglin; Liu, Lei; Dong, Mingdong

    2015-02-14

    Bacterial infections are a serious issue for public health and represent one of the major challenges of modern medicine. In this work, a selective antimicrobial strategy based on triggering of pore-forming toxin, which is secreted by infective bacteria, was designed to fight Staphylococcus aureus. The antimicrobial activity is realized by employing Eucalyptus citriodora oil as antibiotic which in this study is encapsulated in nanoliposomes. PMID:25573466

  8. Antimicrobial durability of air filters coated with airborne Sophora flavescens nanoparticles

    International Nuclear Information System (INIS)

    Airborne biological particles containing viruses, bacteria, and/or fungi can be toxic and cause infections and allergy symptoms. Recently, natural materials such as tea tree oil and Sophora flavescens have shown promising antimicrobial activity when applied as air filter media. Although many of these studies demonstrated excellent antimicrobial efficacy, only a few of them considered external environmental effects such as the surrounding humidity, temperature, and natural degradation of chemicals, all of which can affect the antimicrobial performance of these natural materials. In this study, we investigated the antimicrobial durability of air filters containing airborne nanoparticles from S. flavescens for 5 months. Antimicrobial tests and quantitative chemical analyses were performed every 30 days. Morphological changes in the nanoparticles were also evaluated by scanning electron microscopy. The major antimicrobial compounds remained stable and active for ∼ 90 days at room temperature. After about 90 days, the quantities of major antimicrobial compounds decreased noticeably with a consequent decrease in antimicrobial activity. These results are promising for the implementation of new technologies using natural antimicrobial products and provide useful information regarding the average life expectancy of antimicrobial filters using nanoparticles of S. flavescens. - Graphical abstract: Variations in (a) the concentrations of major antimicrobial chemical compounds on S. flavescens nanoparticle-coated filters: kurarinone, kuraridin, and sophoraflavanone-G and (b) the inactivation rate of antimicrobial filters as a function of time.

  9. Antimicrobial durability of air filters coated with airborne Sophora flavescens nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Eui-seok; Hwang, Gi Byoung [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Nho, Chu Won [Functional Food Center, Korea Institute of Science and Technology (KIST Gangneung Institute), Gangneung, Gangwon-do 210-340 (Korea, Republic of); Kwon, Bo Mi [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Lee, Jung Eun [Biosafety Research Team, National Institute of Environmental Research, Kyungseo-Dong, Seo-Gu, Incheon 404-170 (Korea, Republic of); Seo, SungChul [Department of Environmental Health, College of Medicine, Korea University, Anam-dong 5-ga, Seongbuk-gu, Seoul 136-701 (Korea, Republic of); Bae, Gwi-Nam, E-mail: gnbae@kist.re.kr [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of); Jung, Jae Hee, E-mail: jaehee@kist.re.kr [Center for Environment, Health, and Welfare Research, Korea Institute of Science and Technology (KIST), Hwarangno 14-gil 5, Seongbuk-gu, Seoul 136-791 (Korea, Republic of)

    2013-02-01

    Airborne biological particles containing viruses, bacteria, and/or fungi can be toxic and cause infections and allergy symptoms. Recently, natural materials such as tea tree oil and Sophora flavescens have shown promising antimicrobial activity when applied as air filter media. Although many of these studies demonstrated excellent antimicrobial efficacy, only a few of them considered external environmental effects such as the surrounding humidity, temperature, and natural degradation of chemicals, all of which can affect the antimicrobial performance of these natural materials. In this study, we investigated the antimicrobial durability of air filters containing airborne nanoparticles from S. flavescens for 5 months. Antimicrobial tests and quantitative chemical analyses were performed every 30 days. Morphological changes in the nanoparticles were also evaluated by scanning electron microscopy. The major antimicrobial compounds remained stable and active for ∼ 90 days at room temperature. After about 90 days, the quantities of major antimicrobial compounds decreased noticeably with a consequent decrease in antimicrobial activity. These results are promising for the implementation of new technologies using natural antimicrobial products and provide useful information regarding the average life expectancy of antimicrobial filters using nanoparticles of S. flavescens. - Graphical abstract: Variations in (a) the concentrations of major antimicrobial chemical compounds on S. flavescens nanoparticle-coated filters: kurarinone, kuraridin, and sophoraflavanone-G and (b) the inactivation rate of antimicrobial filters as a function of time.

  10. Animation of Antimicrobial Resistance

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  11. Animation of Antimicrobial Resistance

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    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... Products Advisory Committees Regulatory Information Safety Emergency Preparedness International Programs News & Events Training & Continuing Education Inspections & Compliance ...

  12. Animation of Antimicrobial Resistance

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    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... Emergency Preparedness International Programs News & Events Training & Continuing Education Inspections & Compliance Federal, State & Local Officials Consumers Health ...

  13. Animation of Antimicrobial Resistance

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    Full Text Available ... use of antimicrobial drugs will result in the development of resistant strains of bacteria, complicating clinician's efforts ... Inspections & Compliance Federal, State & Local Officials Consumers Health Professionals Science & Research Industry Scroll back to top Popular ...

  14. Antimicrobial resistance in wildlife

    OpenAIRE

    Vittecoq, M.; Godreuil, S.; Prugnolle, Franck; Durand, P.; Brazier, L; Renaud, N; Arnal, A.; Aberkane, S.; Jean-Pierre, H.; Gauthier-Clerc, M; Thomas, F.; Renaud, F.

    2016-01-01

    The spread of antimicrobial resistance is of major concern for human health and leads to growing economic costs. While it is increasingly hypothesized that wildlife could play an important role in antimicrobial-resistant bacteria dynamics, empirical data remain scarce. The present work builds on a systematic review of the available data in order to highlight the main information we have and to suggest research pathways that should be followed if we aim to fill the gaps in our current knowledg...

  15. Using genomics to identify novel antimicrobials.

    Science.gov (United States)

    Kim, W H; Lillehoj, H S; Gay, C G

    2016-04-01

    There is a critical need in animal agriculture to develop novel antimicrobials and alternative strategies that will help to reduce the use of antibiotics and address the challenges of antimicrobial resistance. High-throughput gene expression analysis is providing new tools that are enabling the discovery of host-derived antimicrobial peptides. Examples of gene-encoded natural antibiotics that have gained attention include antimicrobial peptides such as human granulysin and its multi-species homolog, namely NK-lysin, which provide a protective response against a broad range of microbes and are a principal component of innate immunity in vertebrates. Both granulysin and NK-lysin are localised in cytolytic granules in natural killer and cytotoxic T lymphocytes. Host-derived NK-lysins that were first described in mammals are also found in avian species, and they have been shown to have antimicrobial activities that could potentially be used to control important poultry pathogens. Morphological alterations observed following chicken NK-lysin binding to Eimeria sporozoites and Escherichia coli membranes indicate damage and disruption of cell membranes, suggesting that NK-lysin kills pathogenic protozoans and bacteria by direct interaction. Genotype analysis revealed that chicken NK-lysin peptides derived from certain alleles were more effective at killing pathogens than those derived from others, which could potentially affect susceptibility to diseases. Although the host-derived antimicrobial peptides described in this paper may not, by themselves, be able to replace the antibiotics currently used in animal production, their use as specific treatments based on their known mechanisms of action is showing promising results. PMID:27217171

  16. In Vitro Antimicrobial Potential of the Lichen Parmotrema sp. Extracts against Various Pathogens

    OpenAIRE

    Ritika Chauhan; Jayanthi Abraham

    2013-01-01

      Objective(s):   The ongoing increasing antibiotic resistance is one of the biggest challenges faced by global public health. The perennial need for new antimicrobials against a background of increasing antibiotic resistance in pathogenic and opportunistic microorganisms obliges the scientific community to constantly develop new drugs and antimicrobial agents. Lichens are known prolific sources of natural antimicrobial drugs and biologically active natural products. This study ...

  17. Learning from agriculture: understanding low-dose antimicrobials as drivers of resistome expansion

    Directory of Open Access Journals (Sweden)

    EllenK.Silbergeld

    2014-06-01

    Full Text Available Antimicrobial resistance is a growing public health challenge worldwide, with agricultural use of antimicrobials being one major contributor to the emergence and dissemination of antimicrobial resistance. Globally, most antimicrobials are used in industrial food animal production, a major context for microbiomes encountering low-doses or subtherapeutic-levels of antimicrobial agents from all mechanistic classes. This modern practice exerts broad eco-evolutionary effects on the gut microbiome of food animals, which is subsequently transferred to animal waste. This waste contains complex constituents that are challenging to treat, including antimicrobial resistance determinants and low-dose antimicrobials. Unconfined storage or land deposition of a large volume of animal waste causes its wide contact with the environment and drives the expansion of the environmental resistome through mobilome facilitated horizontal genet transfer. The expanded environmental resistome, which encompasses both natural constituents and anthropogenic inputs, can persist under multiple stressors from agriculture and may re-enter humans, thus posing a public health risk to humans. For these reasons, this review focuses on agricultural antimicrobial use as a laboratory for understanding low-dose antimicrobials as drivers of resistome expansion, briefly summarizes current knowledge on this topic, highlights the importance of research specifically on environmental microbial ecosystems considering antimicrobial resistance as environmental pollution, and calls attention to the needs for longitudinal studies at the systems level.

  18. Integrones y cassettes genéticos de resistencia a antimicrobianos en cepas de Shigella flexneri Integrons and antimicrobial resistance gene cassettes in Shigella flexneri strains

    OpenAIRE

    Jeannette Muñoz A; Helia Bello T; Mariana Domínguez Y; Sergio Mella M; Raúl Zemelman Z; Gerardo González R

    2003-01-01

    Background: The resistance of Shigella flexneri to antimicrobial agents can be associated to the presence of integrons that may contain and express antimicrobial resistance gene cassettes. Aim: To study antimicrobial resistance and the presence of integrons and antimicrobial gene cassettes in Shigella flexneri strains. Material and methods: In vitro susceptibility to 27 antimicrobials was studied in twenty four Shigella flexneri strains isolated from stools. The presence of integrons class 1,...

  19. General principles of antimicrobial therapy.

    Science.gov (United States)

    Leekha, Surbhi; Terrell, Christine L; Edson, Randall S

    2011-02-01

    Antimicrobial agents are some of the most widely, and often injudiciously, used therapeutic drugs worldwide. Important considerations when prescribing antimicrobial therapy include obtaining an accurate diagnosis of infection; understanding the difference between empiric and definitive therapy; identifying opportunities to switch to narrow-spectrum, cost-effective oral agents for the shortest duration necessary; understanding drug characteristics that are peculiar to antimicrobial agents (such as pharmacodynamics and efficacy at the site of infection); accounting for host characteristics that influence antimicrobial activity; and in turn, recognizing the adverse effects of antimicrobial agents on the host. It is also important to understand the importance of antimicrobial stewardship, to know when to consult infectious disease specialists for guidance, and to be able to identify situations when antimicrobial therapy is not needed. By following these general principles, all practicing physicians should be able to use antimicrobial agents in a responsible manner that benefits both the individual patient and the community. PMID:21282489

  20. Antimicrobial stewardship: Limits for implementation

    NARCIS (Netherlands)

    Sinha, Bhanu

    2014-01-01

    Antibiotic stewardship programme (ASP) is a multifaceted approach to improve patients' clinical outcomes, prevent the emergence of antimicrobial resistance, and reduce hospital costs by prudent and focused antimicrobial use. Development of local treatment guidelines according to local ecology, rapid

  1. [Antimicrobial activity of orthodontic band cements].

    Science.gov (United States)

    Pavic, J; Arriagada, M; Elgueta, J; García, C

    1990-01-01

    The prevalence of enamel decalcification and caries beneath orthodontic bands, has indicated the need for a new enamel binding adhesive orthodontic cement. The purpose of this study was to evaluate the antimicrobial activity, in vitro, on Streptococcus mutans and Lactobacillus, acidophillus, of three materials used to cements the orthodontic bands. The cements studied were: Zinc phosphate cement, Glass-ionomer cement, and Policarboxylate cement. Thirty petri plates were seeded with S. mutans, and thirty with L. acidophillus; on each plate three pellet were placed, one of each cement studied. Petri plates were incubated under microaerophilic conditions at 37 C, and checked at 72 hrs. for Streptococcus, mutans, and four days for Lactobacillus acidophillus to evaluate the inhibition zone. The results were tabulated for each material. It was demonstrated that exists important variations in the antimicrobial properties of the materials studied, as in the microbial sensitivity to these cements. PMID:2135908

  2. Substandard/Counterfeit Antimicrobial Drugs

    OpenAIRE

    Kelesidis, Theodoros; Falagas, Matthew E

    2015-01-01

    Substandard/counterfeit antimicrobial drugs are a growing global problem. The most common substandard/counterfeit antimicrobials include beta-lactams (among antibiotics) and chloroquine and artemisin derivatives (among antimalarials). The most common type of substandard/counterfeit antimicrobial drugs have a reduced amount of the active drug, and the majority of them are manufactured in Southeast Asia and Africa. Counterfeit antimicrobial drugs may cause increased mortality and morbidity and ...

  3. Antimicrobial Peptides (AMPs

    Directory of Open Access Journals (Sweden)

    Mehrzad Sadredinamin

    2016-04-01

    Full Text Available Antimicrobial peptides (AMPs are extensive group of molecules that produced by variety tissues of invertebrate, plants, and animal species which play an important role in their immunity response. AMPs have different classifications such as; biosynthetic machines, biological sources, biological functions, molecular properties, covalent bonding patterns, three dimensional structures, and molecular targets.These molecules have multidimensional properties including antimicrobial activity, antiviral activity, antifungal activity, anti-parasite activity, biofilm control, antitumor activity, mitogens activity and linking innate to adaptive immunity that making them promising agents for therapeutic drugs. In spite of this advantage of AMPs, their clinical developments have some limitation for commercial development. But some of AMPs are under clinical trials for the therapeutic purpose such as diabetic foot ulcers, different bacterial infections and tissue damage. In this review, we emphasized on the source, structure, multidimensional properties, limitation and therapeutic applications of various antimicrobial peptides.

  4. Application of nanotechnology in antimicrobial finishing of biomedical textiles

    Science.gov (United States)

    Zille, Andrea; Almeida, Luís; Amorim, Teresa; Carneiro, Noémia; Fátima Esteves, Maria; Silva, Carla J.; Souto, António Pedro

    2014-09-01

    In recent years, the antimicrobial nanofinishing of biomedical textiles has become a very active, high-growth research field, assuming great importance among all available material surface modifications in the textile industry. This review offers the opportunity to update and critically discuss the latest advances and applications in this field. The survey suggests an emerging new paradigm in the production and distribution of nanoparticles for biomedical textile applications based on non-toxic renewable biopolymers such as chitosan, alginate and starch. Moreover, a relationship among metal and metal oxide nanoparticle (NP) size, its concentration on the fabric, and the antimicrobial activity exists, allowing the optimization of antimicrobial functionality.

  5. Quaternary Salts of Chitosan: History, Antimicrobial Features, and Prospects

    Directory of Open Access Journals (Sweden)

    Douglas de Britto

    2011-01-01

    Full Text Available Recently, increasing attention has been paid to water-soluble derivatives of chitosan at its applications. The chemical characteristics and the antimicrobial properties of these salts can play significant role in pharmacological and food areas mainly as carriers for drug delivery systems and as antimicrobial packaging materials. In the current paper, a historical sequence of the main preparative methods, physical chemistry aspects, and antimicrobial activity of chitosan quaternized derivatives are presented and briefly discussed. In general, the results indicated that the quaternary derivatives had better inhibitory effects than the unmodified chitosan.

  6. Application of nanotechnology in antimicrobial finishing of biomedical textiles

    International Nuclear Information System (INIS)

    In recent years, the antimicrobial nanofinishing of biomedical textiles has become a very active, high-growth research field, assuming great importance among all available material surface modifications in the textile industry. This review offers the opportunity to update and critically discuss the latest advances and applications in this field. The survey suggests an emerging new paradigm in the production and distribution of nanoparticles for biomedical textile applications based on non-toxic renewable biopolymers such as chitosan, alginate and starch. Moreover, a relationship among metal and metal oxide nanoparticle (NP) size, its concentration on the fabric, and the antimicrobial activity exists, allowing the optimization of antimicrobial functionality. (topical review)

  7. Antimicrobial Graft Copolymer Gels.

    Science.gov (United States)

    Harvey, Amanda C; Madsen, Jeppe; Douglas, C W Ian; MacNeil, Sheila; Armes, Steven P

    2016-08-01

    In view of the growing worldwide rise in microbial resistance, there is considerable interest in designing new antimicrobial copolymers. The aim of the current study was to investigate the relationship between antimicrobial activity and copolymer composition/architecture to gain a better understanding of their mechanism of action. Specifically, the antibacterial activity of several copolymers based on 2-(methacryloyloxy)ethyl phosphorylcholine [MPC] and 2-hydroxypropyl methacrylate (HPMA) toward Staphylococcus aureus was examined. Both block and graft copolymers were synthesized using either atom transfer radical polymerization or reversible addition-fragmentation chain transfer polymerization and characterized via (1)H NMR, gel permeation chromatography, rheology, and surface tensiometry. Antimicrobial activity was assessed using a range of well-known assays, including direct contact, live/dead staining, and the release of lactate dehydrogenase (LDH), while transmission electron microscopy was used to study the morphology of the bacteria before and after the addition of various copolymers. As expected, PMPC homopolymer was biocompatible but possessed no discernible antimicrobial activity. PMPC-based graft copolymers comprising PHPMA side chains (i.e. PMPC-g-PHPMA) significantly reduced both bacterial growth and viability. In contrast, a PMPC-PHPMA diblock copolymer comprising a PMPC stabilizer block and a hydrophobic core-forming PHPMA block did not exhibit any antimicrobial activity, although it did form a biocompatible worm gel. Surface tensiometry studies and LDH release assays suggest that the PMPC-g-PHPMA graft copolymer exhibits surfactant-like activity. Thus, the observed antimicrobial activity is likely to be the result of the weakly hydrophobic PHPMA chains penetrating (and hence rupturing) the bacterial membrane. PMID:27409712

  8. Effect of packaging materials and treatments on the shelf life of chicken breast treated with antimicrobial agents and stored under refrigerated condition

    OpenAIRE

    Kenawi M.A.; Abdel-Aal H.A.; Abbas H.M.

    2007-01-01

    Sliced chicken breast were treated by dippin in 8% Sodium lactate (SL) for 2 minutes or in 5 % Potassium sorbate (PS) for 5 minutes. The treated and untreated slices were packaged in two different packaging materials, Low density polyethylene bags (LDPE) at atmospheric pressure, and Laminated pouches (B-650) undervacuum, then stored refrigerated at 4oC for 24 days. Color evaluation, total volatile basic nitrogen (TVBN), total bacterial count (TC), psychrophilic bacterial count, coliform group...

  9. Pharmacy intervention on antimicrobial management of critically ill patients

    Directory of Open Access Journals (Sweden)

    Ijo I

    2011-06-01

    Full Text Available Frequent, suboptimal use of antimicrobial drugs has resulted in the emergence of microbial resistance, compromised clinical outcomes and increased costs, particularly in the intensive care unit (ICU. Mounting on these challenges is the paucity of new antimicrobial agents.Objectives: The study aims to determine the impact of prospective pharmacy-driven antimicrobial stewardship in the ICU on clinical and potential financial outcomes. The primary objectives were to determine the mean length of stay (LOS and mortality rate in the ICU resulting from prospective pharmacy interventions on antimicrobial therapy. The secondary objective was to calculate the difference in total drug acquisition costs resulting from pharmacy infectious diseases (ID-related interventions.Methods: In collaboration with an infectious disease physician, the ICU pharmacy team provided prospective audit with feedback to physicians on antimicrobial therapies of 70 patients over a 4-month period in a 31-bed ICU. In comparison with published data, LOS and mortality of pharmacy-monitored ICU patients were recorded. Daily cost savings on antimicrobial drugs and charges for medication therapy management (MTM services were added to calculate potential total cost savings. Pharmacy interventions focused on streamlining, dose optimization, intravenous-to-oral conversion, antimicrobial discontinuation, new recommendation and drug information consult. Antimicrobial education was featured in oral presentations and electronic newsletters for pharmacists and clinicians.Results: The mean LOS in the ICU was 6 days, which was lower than the published reports of LOS ranging from 11 to 36 days. The morality rate of 14% was comparable to the reported range of 6 to 20% in published literature. The total drug cost difference was a negative financial outcome or loss of USD192 associated with ID-related interventions.Conclusion: In collaboration with the infectious disease physician, prospective

  10. Benefits and Risks of Antimicrobial Use in Food-Producing animals

    Directory of Open Access Journals (Sweden)

    Zong-HuiYuan

    2014-06-01

    Full Text Available Benefits and risks of antimicrobial drugs, used in food-producing animals, continue to be complex and controversial issues. This review comprehensively presents the benefits of antimicrobials drugs regarding control of animal diseases, protection of public health, enhancement of animal production, improvement of environment, and effects of the drugs on biogas production and public health associated with antimicrobial resistance. The positive and negative impact, due to ban issue of antimicrobial agents used in food-producing animals, is also included in discussion. As a double-edged sword, use of these drugs in food-animals persists as a great challenge.

  11. Antimicrobial and Antioxidant Activities of Pycnocycla spinosa Extracts

    OpenAIRE

    Mahboubi, Mohaddese; Taghizadeh, Mohsen; Kazempour, Nastaran

    2014-01-01

    Background: Pycnocycla spinosa (P. spinosa) a member of the Umbelliferae family is traditionally used for treatment of different ailments. Objectives: This study aimed to evaluate the total phenolic and flavonoid content of P. spinosa extracts (methanol, ethanol and aqueous) and their antioxidant and antimicrobial effects. Materials and Methods: The antimicrobial activity of different extracts of P. spinosa was evaluated using micro broth dilution. Total phenolic and flavonoid contents were m...

  12. In vitro antimicrobial evaluation of toothpastes with natural compounds

    OpenAIRE

    de Camargo Smolarek, Priscila; Esmerino, Luis Antonio; Chibinski, Ana Cláudia; Bortoluzzi, Marcelo Carlos; dos Santos, Elizabete Brasil; Kozlowski, Vitoldo Antonio

    2015-01-01

    Objectives: This in vitro study evaluated the antimicrobial effects of commercial toothpastes containing natural compounds. Materials and Methods: The study groups were divided based on the natural compound present in the toothpaste composition: Sorbitol (I), tocopherol (II), mint (III), cinnamon/mint (IV), propolis/melaleuca (V), mint/açai (VI), mint/guarana (VII), propolis (VIII), negative control (IX), and the positive control (X). The antimicrobial properties of the toothpastes were teste...

  13. Antimicrobial activity of peppermint essential oil (Mentha piperita L.)

    OpenAIRE

    Shapoval O.G.; Durnova N.A.; Shub G.M.; Golikov A.G.; Raikova S.V.; Rakhmetova A.Yu.

    2011-01-01

    Рurposе. To study antimicrobial activity of fume of the essential oil of peppermint against gram-positive and gram-negative bacteria. Materials and methods: The screening study of antimicrobial activity of solutions of essential oil by disk-diffusion method and activity of essential oil fume of own preparation and pharmaceutical form of oil according to standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Esсherichia coli and 12 clinical strains of staphylococci (6 methicillin-r...

  14. Antimicrobial Activity of Calcium Hydroxide in Endodontics: A Review

    OpenAIRE

    Mohammadi, Z; Shalavi, S.; Yazdizadeh, M

    2012-01-01

    The purpose of endodontic therapy is to preserve the patient's natural teeth without compromising the patient's local or systemic health. Calcium hydroxide has been included in several materials and antimicrobial formulations that are used in several treatment modalities in endodontics, such as inter-appointment intracanal medicaments. The purpose of this article was to review the antimicrobial properties of calcium hydroxide in endodontics. Calcium hydroxide has a high pH (approximately 12.5...

  15. Chitosan-based leather functional coatings with improved antimicrobial properties

    OpenAIRE

    Amaral, J.S.; Fernandes, I.P.; De Pinto, V; Ferreira, M. J.; Barreiro, M.F.

    2012-01-01

    Among the interesting biological activities that have been ascribed to chitosan, the antimicrobial activity is probably the one that generates the higher number of applications. Developing antimicrobial coatings for footwear components to be used in direct contact with the feet is of great interest; both at industrial level (reducing the possibility of material deterioration and quality loss) and from the consumer’s point of view (decreasing skin infections and minimizing...

  16. Antimicrobial Stewardship Programs in Health Care Systems

    OpenAIRE

    MacDougall, Conan; Polk, Ron E.

    2005-01-01

    Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based o...

  17. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... En Español Search FDA Submit search Popular Content Home Food Drugs Medical Devices Radiation-Emitting Products Vaccines, ... Biologics Animal & Veterinary Cosmetics Tobacco Products Animal & Veterinary Home Animal & Veterinary Safety & Health Antimicrobial Resistance Animation of ...

  18. Antimicrobial properties of berries

    OpenAIRE

    Puupponen-Pimiä, Riitta

    2007-01-01

    Berries, especially their antimicrobial properties, have been studied intensively at VTT over the past ten years in several research projects. In these in vitro studies phenolic berry extracts of common Nordic berries selectively inhibited the growth of harmful bacteria and human intestinal pathogens, without affecting the growth of beneficial lactic acid bacteria.

  19. 抗菌肽histatherin研究进展%Research Progress of Antimicrobial Peptide Histatherin

    Institute of Scientific and Technical Information of China (English)

    高帅; 鞠志花; 宿烽; 王长法

    2011-01-01

    抗菌肽产于机体组织、具有广谱抗菌活性和独特抗菌的机制.对抗菌肽的研究有助于开发抗菌肽药物、进行动物抗性育种和培育抗菌肽转基因动物.论文对一种新的牛抗菌肽histatherin的研究进展进行概述.%As the drug-resistance and challenge to food safety caused by the abuse of antibiotics is becoming serious , more and more attentions have been attracted to the antimicrobial peptides, which has characteristics of antimicrobial mechanism and wide antimicrobial spectrum. The research on antimicrobial peptides will contribute to antimicrobial peptides drug development, resistive breeding, and transgenic animal breeding. This article introduced the studies about a new bovine antimicrobial peptide-histatherin.

  20. A Proposal for Including Patient-Generated Web-based Creative Writing Material into Psychotherapy: Advantages and Challenges

    OpenAIRE

    Lawver, Timothy

    2008-01-01

    Creative writing presents both a challenging and promising modality for psychotherapy. Though it has been used in various settings, the application within a session can be difficult. This case study presents a use of a web-based format to engage a resistant patient through her creative writing. Benefits and potential pitfalls of using a patient’s writing in therapy are discussed.

  1. Antimicrobial activity of Rhodobryum ontariense

    Directory of Open Access Journals (Sweden)

    Sabovljević Aneta

    2012-01-01

    Full Text Available The antimicrobial activity of dimethyl sulfoxide extract of moss Rhodobryum ontariense (Kindb. Kindb. was evaluated by microdilution method against eight bacterial (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Enterobacter cloacae, Listeria monocytogens, Bacillus cereus, Micrococcus flavus and Staphylococcus aureus and five fungal species (Aspergillus versicolor, Aspergillus fumigatus, Penicillium funiculosum, Penicillium ochrochloron and Trichoderma viride. The extract was proven to be active against all the bacteria and funghi tested but to varying degrees. It showed better inhibitory activity compared to the known antifungal drug against T. viride (MIC 100 and 200 μg/ml, respectively. This finding implies that R. ontariense could be considered as a promising material for natural antifungal products.

  2. Antimicrobial activity of galls of Quercus infectoria

    OpenAIRE

    Fırat Zafer Mengeloğlu; Umre Metin; Nesibe Özdemir; M. Kadir Oduncu

    2011-01-01

    Objectives: Gall oak (Quercus infectoria) is a species of tree belonging to fagaceae family and its galls has been used in the treatment of burn wounds traditionally. In this study, it is aimed to investigate the antimicrobial activity of the extract of oak galls on some microorganisms.Materials and methods: With using microdilution method, a solution which was obtained by boiling the galls was studied on 20 staphylococci, 20 Pseudomonas aeruginosa and 20 Candida albicans isolates which were ...

  3. Antimicrobial effects of methanolic extracts of some species of Stachys and Phlomis

    OpenAIRE

    Morteza-Semnani, K.; Saeedi, M.; Mahdavi, M. R.; Rahimi, F

    2007-01-01

    Abstract Background and purpose: The genus Phlomis and Stachys (Labiatae) are widely distributed in Iran. There are no reports on the antimicrobial activity of some of these plants. The medicinal properties attributed to the genus Phlomis and Stachys prompted us to investigate the antimicrobial activity of the methanolic extracts of Phlomis bruguieri, P. herba-venti, P. olivieri, Stachys byzantina, S. inflata, S. lavandulifolia and S. laxa.Materials and Methods: The antimicrobial activity of ...

  4. Osteoblast integration of dental implant materials after challenge by sub-gingival pathogens:a co-culture study in vitro

    Institute of Scientific and Technical Information of China (English)

    Bingran Zhao; Henny C van der Mei; Minie Rustema-Abbing; Henk J Busscher; Yijin Ren

    2015-01-01

    Sub-gingival anaerobic pathogens can colonize an implant surface to compromise osseointegration of dental implants once the soft tissue seal around the neck of an implant is broken. In vitro evaluations of implant materials are usually done in monoculture studies involving either tissue integration or bacterial colonization. Co-culture models, in which tissue cells and bacteria battle simultaneously for estate on an implant surface, have been demonstrated to provide a better in vitro mimic of the clinical situation. Here we aim to compare the surface coverage by U2OS osteoblasts cells prior to and after challenge by two anaerobic sub-gingival pathogens in a co-culture model on differently modified titanium (Ti), titanium-zirconium (TiZr) alloys and zirconia surfaces. Monoculture studies with either U2OS osteoblasts or bacteria were also carried out and indicated significant differences in biofilm formation between the implant materials, but interactions with U2OS osteoblasts were favourable on all materials. Adhering U2OS osteoblasts cells, however, were significantly more displaced from differently modified Ti surfaces by challenging sub-gingival pathogens than from TiZr alloys and zirconia variants. Combined with previous work employing a co-culture model consisting of human gingival fibroblasts and supra-gingival oral bacteria, results point to a different material selection to stimulate the formation of a soft tissue seal as compared to preservation of osseointegration under the unsterile conditions of the oral cavity.

  5. Covering Materials Incorporating Radiation-Preventing Techniques to Meet Greenhouse Cooling Challenges in Arid Regions: A Review

    OpenAIRE

    Ahmed M. Abdel-Ghany; Al-Helal, Ibrahim M.; Alzahrani, Saeed M.; Alsadon, Abdullah A.; Ilias M. Ali; Elleithy, Rabeh M.

    2012-01-01

    Cooling greenhouses is essential to provide a suitable environment for plant growth in arid regions characterized by brackish water resources. However, using conventional cooling methods are facing many challenges. Filtering out near infra-red radiation (NIR) at the greenhouse cover can significantly reduce the heating load and can solve the overheating problem of the greenhouse air. This paper is to review (i) the problems of using conventional cooling methods and (ii) the advantages of gree...

  6. Antimicrobial activity of peppermint essential oil (Mentha piperita L.

    Directory of Open Access Journals (Sweden)

    Shapoval O.G.

    2011-12-01

    Full Text Available Рurposе. To study antimicrobial activity of fume of the essential oil of peppermint against gram-positive and gram-negative bacteria. Materials and methods: The screening study of antimicrobial activity of solutions of essential oil by disk-diffusion method and activity of essential oil fume of own preparation and pharmaceutical form of oil according to standard strains of Staphylococcus aureus, Pseudomonas aeruginosa, Esсherichia coli and 12 clinical strains of staphylococci (6 methicillin-resistant and 6 methicillin-sensitive has been carried out. Results: Essential oil of own preparation and pharmaceutical form showed equal antimicrobial activity against strains of staphylococci. Essential oil of own preparation has been determined to reveal higher activity against gram-negative strains. Conclusion: Received data have proved the presence of antimicrobial activity against all strains of microorganisms and mostly against staphy-lococci

  7. The antimicrobial efficiency of silver activated sorbents

    Science.gov (United States)

    Đolić, Maja B.; Rajaković-Ognjanović, Vladana N.; Štrbac, Svetlana B.; Rakočević, Zlatko Lj.; Veljović, Đorđe N.; Dimitrijević, Suzana I.; Rajaković, Ljubinka V.

    2015-12-01

    This study is focused on the surface modifications of the materials that are used for antimicrobial water treatment. Sorbents of different origin were activated by Ag+-ions. The selection of the most appropriate materials and the most effective activation agents was done according to the results of the sorption and desorption kinetic studies. Sorption capacities of selected sorbents: granulated activated carbon (GAC), zeolite (Z), and titanium dioxide (T), activated by Ag+-ions were following: 42.06, 13.51 and 17.53 mg/g, respectively. The antimicrobial activity of Ag/Z, Ag/GAC and Ag/T sorbents were tested against Gram-negative bacteria E. coli, Gram-positive bacteria S. aureus and yeast C. albicans. After 15 min of exposure period, the highest cell removal was obtained using Ag/Z against S. aureus and E. coli, 98.8 and 93.5%, respectively. Yeast cell inactivation was unsatisfactory for all three activated sorbents. The antimicrobial pathway of the activated sorbents has been examined by two separate tests - Ag+-ions desorbed from the activated surface to the aqueous phase and microbial cell removal caused by the Ag+-ions from the solid phase (activated surface sites). The results indicated that disinfection process significantly depended on the microbial-activated sites interactions on the modified surface. The chemical state of the activating agent had crucial impact to the inhibition rate. The characterization of the native and modified sorbents was performed by X-ray diffraction technique, X-ray photoelectron spectroscopy and scanning electron microscope. The concentration of adsorbed and released ions was determined by inductively coupled plasma optical emission spectroscopy and mass spectrometry. The antimicrobial efficiency of activated sorbents was related not only to the concentration of the activating agent, but moreover on the surface characteristics of the material, which affects the distribution and the accessibility of the activating agent.

  8. State of the art and challenges in development of electrical contact materials in the light of the RoHS directive

    Directory of Open Access Journals (Sweden)

    Ćosović V.

    2012-01-01

    Full Text Available The article surveys current state of the art and challenges in the development of the electrical contact materials in the light of the EU Directive on Restriction of Hazardous Substances (RoHS. The focus was placed on widely used silver-cadmium alloys. According to this directive, as of July 1, 2006, use of six hazardous materials, including cadmium, are restricted for applicable electrical and electronic products intended for the EU market. In contrast, traditionally preferred material for production of electrical contacts is Ag-CdO, due to its outstanding functional properties. These conflicting interests result in present state where RoHS directive has not yet been implemented in its original form and has undergone numerous amendments and exceptions regarding the use of cadmium. Main reason for this seems to be the unrealistic time frame imposed by legislation. Although, significant effort has been put into research and development of alternative materials, there are still cases where adequate replacement materials had not been found. Therefore, importance of synchronicity between legislation and technological progress i.e. communication between legislative administration and industry and academia is brought to light as well as some common issues that may arise with an introduction of new replacement materials or product modification. [Projekat Ministarstva nauke Republike SRbije, br. OI 172037 and TR 34023

  9. Antimicrobial peptides in crustaceans

    OpenAIRE

    RD Rosa; MA Barracco

    2010-01-01

    Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs) are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP fam...

  10. Antimicrobial Drugs in the Home

    Centers for Disease Control (CDC) Podcasts

    2006-10-19

    Survey participants in the United Kingdom admitted keeping leftover antimicrobial drugs for future use and taking them without medical advice. Dr. J. Todd Weber, director of CDC's Office of Antimicrobial Resistance, advises against the practice, which can be dangerous and can promote antimicrobial drug resistance.  Created: 10/19/2006 by Emerging Infectious Diseases.   Date Released: 10/26/2006.

  11. Challenges in ensuring radiological safety and nuclear forensic for malicious acts involving nuclear and other radioactive material

    International Nuclear Information System (INIS)

    Nuclear and other radioactive materials may get smuggled into the country aimed at malicious acts. Radioactive material detected accidentally or during inspection at the entry points/national borders may indicate illicit trafficking for the purpose of nuclear/radiological terrorism. As country requires prevention and preparedness for response to these malicious acts, nuclear forensic techniques are to be developed incorporating radiological safety aspects. Nuclear forensics helps in determining the origin, intended use, legal owner and the smuggled route etc. by using fingerprinting as well as comparison with reference data. The suggested sequence of methods for analysis of radioactive material/samples will be radiological assessment, physical characterization, traditional forensic analysis, isotope analysis along with elemental/chemical analysis

  12. The Ethical Significance of Antimicrobial Resistance

    OpenAIRE

    Littmann, Jasper; Viens, A. M.

    2015-01-01

    In this paper, we provide a state-of-the-art overview of the ethical challenges that arise in the context of antimicrobial resistance (AMR), which includes an introduction to the contributions to the symposium in this issue. We begin by discussing why AMR is a distinct ethical issue, and should not be viewed purely as a technical or medical problem. In the second section, we expand on some of these arguments and argue that AMR presents us with a broad range of ethical problems that must be ad...

  13. Real-Time Optical Antimicrobial Susceptibility Testing

    DEFF Research Database (Denmark)

    Fredborg, Marlene; Andersen, Klaus R; Jørgensen, Erik;

    2013-01-01

    Rapid antibiotic susceptibility testing is in highly demand in health-care fields as antimicrobial resistant bacterial strains emerge and spread. Here we describe an optical screening system (oCelloScope), which based on time-lapse imaging of 96 bacteria-antibiotic combinations at a time......, introduces real-time detection of bacterial growth and antimicrobial susceptibility, with imaging material to support the automatically generated graphs. Automated antibiotic susceptibility tests of a monoculture showed statistically significant antibiotic effect within 6 minutes and within 30 minutes in...... complex samples from pigs suffering from catheter associated urinary tract infections. The oCelloScope system provides a fast high-throughput screening method to detect bacterial susceptibility that may entail earlier diagnosis and introduction of appropriate targeted therapy and thus combat the threat...

  14. Condensing Heat Exchanger with Hydrophilic Antimicrobial Coating

    Science.gov (United States)

    Thomas, Christopher M. (Inventor); Ma, Yonghui (Inventor)

    2014-01-01

    A multi-layer antimicrobial hydrophilic coating is applied to a substrate of anodized aluminum, although other materials may form the substrate. A silver layer is sputtered onto a thoroughly clean anodized surface of the aluminum to about 400 nm thickness. A layer of crosslinked, silicon-based macromolecular structure about 10 nm thickness overlies the silver layer, and the outermost surface of the layer of crosslinked, silicon-based macromolecular structure is hydroxide terminated to produce a hydrophilic surface with a water drop contact angle of less than 10.degree.. The coated substrate may be one of multiple fins in a condensing heat exchanger for use in the microgravity of space, which has narrow channels defined between angled fins such that the surface tension of condensed water moves water by capillary flow to a central location where it is pumped to storage. The antimicrobial coating prevents obstruction of the capillary passages.

  15. The Challenge of Characterising Large Assemblages of Exotic Materials: a case study of the obsidian from Domuztepe, SE Turkey

    Directory of Open Access Journals (Sweden)

    Elizabeth Healey

    2009-09-01

    Full Text Available Obsidian artefacts from Domuztepe (a large late Neolithic site in the Kahramanmaraş plain in south-east Turkey belonging to the Halaf culture and dated to c. 6000-5500 cal. BC account for about 18%, or some 10,000 artefacts, of the chipped stone assemblage. Obsidian is one of the few non-local materials at Domuztepe and as well as being used to make tools it is also used to make items of jewellery, mirrors, bowls and axe-like objects. We know from the geochemical analysis of a relatively small number of artefacts that the obsidian was imported from eight different and widely separated sources in Central, NE and SE Anatolia. These sources are between 200 and 900km distant from Domuztepe. All these factors suggest that obsidian was valued not only as a raw material for tool manufacture but also as a material from which to make luxury items. As an exotic material it is also likely to have a key role in forging and maintaining social and economic relationships, both within the site and more widely. Understanding of the origins of the obsidians and the form in which they were obtained, worked and used, context by context, is key to this. However, difficulties arise with provenancing such a large assemblage, not least because conventional geo-chemical methods are unfeasibly expensive. This article documents the approaches we have developed to overcome this problem.

  16. Consideration on the potential increasing risk of the proliferation of nuclear materials vs. Nonproliferation challenges from nuclear renaissance

    International Nuclear Information System (INIS)

    Managing Proliferation Risk in the Global Expansion of Nuclear Energy, enhancing the Security and Safety for the management of Nuclear Material (NM) is of high level of importance. It is to be noted that the IAEA has proposed the nuclear fuel cycle center concept for international management aiming at decreasing the Proliferation Risk of NM. The paper will presents some specific Security and Safety aspects need in order to apply and to improve its Nuclear Security Regime (Framework), the State Nuclear Security Risk Management associated with the transport of NM since sabotage or a malicious may happen during transport and potentially can involve the intentional increasing of the proliferation risk of such material. Such actions could result in severe deterministic health effects to population. Some additional or improved measures related to Nuclear Security, efforts to secure nuclear material and other radioactive material there will be also presented. An assessment of vulnerability of possible transport routes will be approached. It is to be noted that this paper considers some results carried out under the IAEA Scientific Research Contract on The State Management of Nuclear Security Regime (Framework), where the author is the CSI (Chief Scientific Investigator). (author)

  17. Simulations of inorganic-bioorganic interfaces to discover new materials: insights, comparisons to experiment, challenges, and opportunities.

    Science.gov (United States)

    Heinz, Hendrik; Ramezani-Dakhel, Hadi

    2016-01-21

    Natural and man-made materials often rely on functional interfaces between inorganic and organic compounds. Examples include skeletal tissues and biominerals, drug delivery systems, catalysts, sensors, separation media, energy conversion devices, and polymer nanocomposites. Current laboratory techniques are limited to monitor and manipulate assembly on the 1 to 100 nm scale, time-consuming, and costly. Computational methods have become increasingly reliable to understand materials assembly and performance. This review explores the merit of simulations in comparison to experiment at the 1 to 100 nm scale, including connections to smaller length scales of quantum mechanics and larger length scales of coarse-grain models. First, current simulation methods, advances in the understanding of chemical bonding, in the development of force fields, and in the development of chemically realistic models are described. Then, the recognition mechanisms of biomolecules on nanostructured metals, semimetals, oxides, phosphates, carbonates, sulfides, and other inorganic materials are explained, including extensive comparisons between modeling and laboratory measurements. Depending on the substrate, the role of soft epitaxial binding mechanisms, ion pairing, hydrogen bonds, hydrophobic interactions, and conformation effects is described. Applications of the knowledge from simulation to predict binding of ligands and drug molecules to the inorganic surfaces, crystal growth and shape development, catalyst performance, as well as electrical properties at interfaces are examined. The quality of estimates from molecular dynamics and Monte Carlo simulations is validated in comparison to measurements and design rules described where available. The review further describes applications of simulation methods to polymer composite materials, surface modification of nanofillers, and interfacial interactions in building materials. The complexity of functional multiphase materials creates

  18. Clinical and antimicrobial profile of Acinetobacter spp.: An emerging nosocomial superbug

    OpenAIRE

    Purti C Tripathi; Sunita R Gajbhiye; Gopal Nandlal Agrawal

    2014-01-01

    Background: Recently, Acinetobacter has emerged as significant hospital pathogen, notoriously known to acquire antibiotic resistance to most of the commonly prescribed antimicrobials. Many risk factors are associated with Acinetobacter infections, especially in patients in intensive care unit (ICU). This study aims to isolate Acinetobacter from various clinical specimens and to determine its antimicrobial sensitivity pattern. Materials and Methods: Identification, speciation and antimicro...

  19. Evaluation of antimicrobial effectiveness of ophthalmic drops according to the pharmacopeial tests criteria

    OpenAIRE

    N Samadi; Tarighi, P.; M.R Fazeli; H Mehrgan

    2009-01-01

    ABSTRACT Background: In this study antimicrobial effectiveness test was performed on eye-drops which had high microbial contaminations in hospital practice to find out whether their antimicrobial efficacies affect the magnitude of microbial contamination during their uses. Materials and Methods: Artificial tear, atropine sulfate, betamethasone, homatropine hydrobromide, phenylephrine hydrochloride, phenylephrine zinc, pilocarpine hydrochloride, tetracaine hydrochloride and tropicamide eye-dro...

  20. Development of antimicrobial textile materials for shoes

    OpenAIRE

    Matos, Joaquim Filipe Vasconcelos

    2014-01-01

    Dissertação de mestrado em Design e Marketing Atualmente, o sector do calçado tem um papel importante na economia Portuguesa e está entre os sectores com melhor desempenho relativamente às exportações. Este sector exporta cerca de 95% do total da produção nacional, tem o segundo preço médio de venda mais alto a nível mundial, perto de convergir com o líder Itália, utiliza tecnologia inovadora na produção, o que determina a capacidade e a importância deste sector em compreender ...

  1. Antimicrobial hydrogels: a new weapon in the arsenal against multidrug-resistant infections.

    Science.gov (United States)

    Ng, Victor W L; Chan, Julian M W; Sardon, Haritz; Ono, Robert J; García, Jeannette M; Yang, Yi Yan; Hedrick, James L

    2014-11-30

    The rapid emergence of antibiotic resistance in pathogenic microbes is becoming an imminent global public health problem. Treatment with conventional antibiotics often leads to resistance development as the majority of these antibiotics act on intracellular targets, leaving the bacterial morphology intact. Thus, they are highly prone to develop resistance through mutation. Much effort has been made to develop macromolecular antimicrobial agents that are less susceptible to resistance as they function by microbial membrane disruption. Antimicrobial hydrogels constitute an important class of macromolecular antimicrobial agents, which have been shown to be effective in preventing and treating multidrug-resistant infections. Advances in synthetic chemistry have made it possible to tailor molecular structure and functionality to impart broad-spectrum antimicrobial activity as well as predictable mechanical and rheological properties. This has significantly broadened the scope of potential applications that range from medical device and implant coating, sterilization, wound dressing, to antimicrobial creams for the prevention and treatment of multidrug-resistant infections. In this review, advances in both chemically and physically cross-linked natural and synthetic hydrogels possessing intrinsic antimicrobial properties or loaded with antibiotics, antimicrobial polymers/peptides and metal nanoparticles are highlighted. Relationships between physicochemical properties and antimicrobial activity/selectivity, and possible antimicrobial mechanisms of the hydrogels are discussed. Approaches to mitigating toxicity of metal nanoparticles that are encapsulated in hydrogels are reviewed. In addition, challenges and future perspectives in the development of safe and effective antimicrobial hydrogel systems especially involving co-delivery of antimicrobial polymers/peptides and conventional antimicrobial agents for eventual clinical applications are presented. PMID:25450263

  2. Targeting an antimicrobial effector function in insect immunity as a pest control strategy

    Science.gov (United States)

    Bulmer, Mark S.; Bachelet, Ido; Raman, Rahul; Rosengaus, Rebeca B.; Sasisekharan, Ram

    2009-01-01

    Insect pests such as termites cause damages to crops and man-made structures estimated at over $30 billion per year, imposing a global challenge for the human economy. Here, we report a strategy for compromising insect immunity that might lead to the development of nontoxic, sustainable pest control methods. Gram-negative bacteria binding proteins (GNBPs) are critical for sensing pathogenic infection and triggering effector responses. We report that termite GNBP-2 (tGNBP-2) shows β(1,3)-glucanase effector activity previously unknown in animal immunity and is a pleiotropic pattern recognition receptor and an antimicrobial effector protein. Termites incorporate this protein into the nest building material, where it functions as a nest-embedded sensor that cleaves and releases pathogenic components, priming termites for improved antimicrobial defense. By means of rational design, we present an inexpensive, nontoxic small molecule glycomimetic that blocks tGNBP-2, thus exposing termites in vivo to accelerated infection and death from specific and opportunistic pathogens. Such a molecule, introduced into building materials and agricultural methods, could protect valuable assets from insect pests. PMID:19506247

  3. Preparing for new solar cells through integrated research: challenges in translating social robustness into the selection of materials

    OpenAIRE

    Åm, Heidrun; Sørensen, Knut Holtan

    2015-01-01

    Research policy and research councils increasingly demand responsible innovation and socially robust knowledge. But what does that imply? Theories say little about how to translate social robustness into practice. In this chapter, we report from an integrated project on solar cells where Ethical, Legal and Social Aspects (ELSA) oriented scholars interacted with material scientists. The aim of the project was twofold. First, to achieve social robustness in the selection of ma...

  4. Antimicrobial susceptibilities of Clostridium difficile.

    OpenAIRE

    Shuttleworth, R; Taylor, M.; Jones, D M

    1980-01-01

    The antimicrobial susceptibilities of 78 strains of Clostridium difficile isolated from patients with and without gastrointestinal symptoms were determined and compared. Strains from patients with symptoms were more likely to show resistance to antibiotics. The antimicrobial susceptibilities of toxigenic and non-toxigenic strains were found to be similar.

  5. Engineering Antimicrobials Refractory to Resistance

    Science.gov (United States)

    Multi-drug resistant superbugs are a persistent problem in modern health care, demonstrating the need for a new class of antimicrobials that can address this concern. Triple-acting peptidoglycan hydrolase fusions are a novel class of antimicrobials which have qualities well suited to avoiding resis...

  6. A Review of Two Nanocomposite Insulating Materials Models: Lewis’ Contribution in the Development of the Models, their Differences, their Similarities and Future Challenges

    Directory of Open Access Journals (Sweden)

    M. Danikas

    2014-08-01

    Full Text Available Nanocomposite polymers are nowadays a major field of research. This paper investigates the interpretational possibilities of two models developed, namely, Tsagaropoulos’ model and Tanaka’s model. Particular emphasis is given to Lewis’ model, which was the first one to be proposed and whose contribution to the aforementioned models was significant. The two models were developed separately and independently from each other. They both consider various layers around the nanoparticles. They both consider well bonded and more loosen layers. Similarities and differences between the two models are pointed out and discussed as well as possibilities for further research in order to shed light on some aspects of electrical phenomena in these materials. Particular emphasis is given to the interfaces between the nanoparticles and the surrounding base material. Comments are offered regarding the challenges facing the two models w.r.t. the interpretation of discharges on nanocomposite surfaces. Possible new areas of research are suggested and new challenges for the aforementioned models are pointed out.

  7. Covering Materials Incorporating Radiation-Preventing Techniques to Meet Greenhouse Cooling Challenges in Arid Regions: A Review

    Directory of Open Access Journals (Sweden)

    Ahmed M. Abdel-Ghany

    2012-01-01

    Full Text Available Cooling greenhouses is essential to provide a suitable environment for plant growth in arid regions characterized by brackish water resources. However, using conventional cooling methods are facing many challenges. Filtering out near infra-red radiation (NIR at the greenhouse cover can significantly reduce the heating load and can solve the overheating problem of the greenhouse air. This paper is to review (i the problems of using conventional cooling methods and (ii the advantages of greenhouse covers that incorporate NIR reflectors. This survey focuses on how the cover type affects the transmittance of photosynthetically active radiation (PAR, the reflectance or absorptance of NIR and the greenhouse air temperature. NIR-reflecting plastic films seem to be the most suitable, low cost and simple cover for greenhouses under arid conditions. Therefore, this review discusses how various additives should be incorporated in plastic film to increase its mechanical properties, durability and ability to stand up to extremely harsh weather. Presently, NIR-reflecting covers are able to reduce greenhouse air temperature by no more than 5°C. This reduction is not enough in regions where the ambient temperature may exceed 45°C in summer. There is a need to develop improved NIR-reflecting plastic film covers.

  8. Cationic Antimicrobial Peptide Cytotoxicity

    OpenAIRE

    Laverty, Garry; Gilmore, Brendan

    2014-01-01

    Fluorescence microscopy serves as a valuable tool for assessing the structural integrity and viability of eukaryotic cells. Through the use of calcein AM and the DNA stain 4,6-diamidino-2 phenylindole (DAPI), cell viability and membrane integrity can be qualified. Our group has previously shown the ultra-short cationic antimicrobial peptide H-OOWW-NH2; the amphibian derived 27-mer peptide Maximin-4and the ultra-short lipopeptide C12-OOWW-NH2 to be effective against a range of bacterial biofil...

  9. The Challenge of Time-Dependent Control of Both Processing and Performance of Materials at the Mesoscale, and the MaRIE Project

    Science.gov (United States)

    Barnes, Cris W.

    DOE and NNSA are recognizing a mission need for flexible and reduced-cost product-based solutions to materials through accelerated qualification, certification, and assessment. The science challenge lies between the nanoscale of materials and the integral device scale, at the middle or ''mesoscale'' where interfaces, defects, and microstructure determine the performance of the materials over the lifecycle of the intended use. Time-dependent control of the processing, structure and properties of materials at this scale lies at the heart of qualifying and certifying additive manufactured parts; experimental data of high fidelity and high resolution are necessary to discover the right physical mechanisms to model and to validate and calibrate those reduced-order models in codes on Exascale computers. The scientific requirements to do this are aided by a revolution in coherent imaging of non-periodic features that can be combined with scattering off periodic structures. This drives the need to require a coherent x-ray source, brilliant and high repetition rate, of sufficiently high energy to see into and through the mesoscale. The Matter-Radiation Interactions in Extremes (MaRIE) Project is a proposal to build such a very-high-energy X-ray Free Electron Laser.

  10. Antimicrobial resistance of thermophilic Campylobacter

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Engberg, J.

    Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice ...... acquired resistance genes, has not become widespread so far. However, resistance genes originating from both Gram-positive and Gram-negative bacterial species have been found, showing the potential for acquired resistance to emerge in Campylobacter.......Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice...... for the treatment of infections, macrolides and fluoroquinolones has emerged as a clinical problem and interventions to reduce this are recommended. Resistance to fluoroquinolones and macrolides is mediated by chromosomal mutations. Resistance to other relevant antimicrobial agents, mediated by...

  11. The future of antimicrobial therapy in the era of antibiotic resistance in cystic fibrosis pulmonary infection.

    Science.gov (United States)

    McCaughey, G; Gilpin, Df; Elborn, Js; Tunney, Michael M

    2013-08-01

    Cystic fibrosis (CF) is characterised by chronic polymicrobial airway infection and inflammation, which is the major cause of morbidity and mortality. Aggressive use of antimicrobials has been fundamental in increasing the life expectancy of CF patients in recent years. However, enhanced culture and non-culture based detection methods have identified bacteria in the CF lung not previously isolated from CF patients by routine diagnostic microbiology Coupled with increasing antimicrobial resistance, the future of antimicrobial therapy in CF respiratory infection remains challenging. New strategies are needed to address these problems and ensure improvements in life expectancy are maintained. Potential future strategies include the use of new antimicrobial agents and formulations currently in clinical trials, alternative methods of selecting appropriate therapeutic regimens, determination of the pathogenicity of species newly associated with CF and the development of new antimicrobials and adjuvants for use in clinical practice. PMID:23964628

  12. Antimicrobial Effects of Honey on Bacillus Cereus

    Directory of Open Access Journals (Sweden)

    This paper should be cited as: Javadzadeh M, Najafi M, Rezaei M, Dastoor M, Behzadi AS, Amiri A . [ Antimicrobial Effects of Honey on Bacillus Cereus ]. MLJ. 201 4 ; 8 ( 2 : 55 - 61 [Article in Persian] Javadzadeh, M. (MSc

    2014-05-01

    Full Text Available Background and Objective: Honey is a healthy and nutritious food that has been used for a long time as a treatment for different diseases. One of the applied properties of honey is its antimicrobial effect, which differs between different types of honey due to variation of phenolic and antioxidant compositions. This study aimed to assess antimicrobial effect of honey on Bacillus cereus, considering its chemical properties. Material and Methods: Three samples of honey (A1 and A2 of Khorasan Razavi Province and A3 of South Khorasan province (were prepared and studied in terms of chemical parameters .The antibacterial effect of honey was surveyed throughTurbidimeter using spectrometer with incubator time of 2, 4, 6, and 8hrs. the level of turbidity caused by bacterium growth was measured at different times with a wavelength of 600nm. Results: According to the study, the samples containing higher concentration of polyphenol has more antimicrobial activity. The samples of A2, A3, and A1 had the highest concentration of polyphenol, respectively. Conclusion: The results indicate the prebiotic effect of honey that can be justified by the presence of fructo-oligosacharids and vitamin B. Keywords: Honey, Bacillus Cereus, Antibacterial, Turbidimetry.

  13. Antimicrobial Activity of Acanthephippium bicolor, Lindley

    Directory of Open Access Journals (Sweden)

    Kala, S.

    2010-01-01

    Full Text Available The Kolli hills, a part of Eastern Ghats of India is a treasure of medicinal plants. An attempt is made to gather information about the traditional use of herbs from the local healers. Acanthephippium bicolor Lindley is being used to treat urinary tract infection. Different parts (leaf, bulb and root are collected in two seasons (summer and winter and phytochemicals present in them are analyzed. Leaf is found to possess most of the phytochemicals. Hence leaf is selected as study material. Antimicrobial activity of the various solvent extracts (methanol, ethanol, chloroform, acetone, ethyl acetate, benzene and hexane is screened for both summer and winter samples. Of the 35 organisms studied, Staphylococcus aureus, Streptococcus foecalis, Bacillus cereus, Proteus vulgaris, Proteus mirabilis, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella dysenteriae, Escherichia coli, Microsporum audouinii, Microsporum fulvum, Candida albicans and Trichophyton rubrum are found to be sensitive to leaf extracts. The Gram-positive bacteria are found to be more sensitive than Gram-negative bacteria and fungi. The inhibition is found to be more in methanol extract. This proves that the bioactive compounds reside in methanolic extract. When the summer and winter samples are compared for their antimicrobial efficacy, there is no significant difference. This proves that there is no impact of season on antimicrobial activity of this plant. This research proves that Acanthephippium bicolor Lindley would be the best herbal medicine for Urinary Tract Infection and leaves can be used as herbal and scientific medicine throughout the year as there is no seasonal impact.

  14. Antimicrobial activity of galls of Quercus infectoria

    Directory of Open Access Journals (Sweden)

    Fırat Zafer Mengeloğlu

    2011-09-01

    Full Text Available Objectives: Gall oak (Quercus infectoria is a species of tree belonging to fagaceae family and its galls has been used in the treatment of burn wounds traditionally. In this study, it is aimed to investigate the antimicrobial activity of the extract of oak galls on some microorganisms.Materials and methods: With using microdilution method, a solution which was obtained by boiling the galls was studied on 20 staphylococci, 20 Pseudomonas aeruginosa and 20 Candida albicans isolates which were obtained from various clinical samples and the values of minimum inhibitor concentration (MIC were detected.Results: At the end of incubation MIC50 and MIC90 values were determined as 0,5 and 1 μg/ml for staphylococci, 1 and 2 μg/ml for Pseudomonas, 2 and 2 μg/ml for Candida, respectively.Conclusion: As a result, we concluded that galls of Q.infectoria has antimicrobial effect on common factors of burn wound infections. Larger studies about the antimicrobial and antiinflamatorial activity and in vivo effect of topical treatment of Q.infectoria will obtain more accurate data about using this plant in the treatment of burn wounds.

  15. Antimicrobial activity of antiproteinases.

    Science.gov (United States)

    Sallenave, J M

    2002-04-01

    Low-molecular-mass neutrophil elastase inhibitors have been shown to be important in the control of lung inflammation. In addition to inhibiting the enzyme neutrophil elastase, these low-molecular-mass compounds (10 kDa) have been shown to have other activities. For example, secretory leucocyte proteinase inhibitor (SLPI) and elastase-specific inhibitor/SKALP (skin-derived antileucoproteinase)/elafin have also been shown to have "defensin"-like antimicrobial activities. Indeed, these inhibitors have antimicrobial properties in vitro against bacteria, fungi and, potentially, HIV. In addition, we have shown, using an adenovirus-mediated gene transfer overexpression strategy, that elafin is also active against Pseudomonas aeruginosa infection in mice in vivo. The mechanism of action is currently under investigation. In addition to these direct or indirect effects on microbes, it has been shown that lipopolysaccharide is able to up-regulate SPLI production in macrophages in vitro, and that the addition of recombinant SLPI to human monocytes or the transfection of macrophages with SPLI can down-regulate pro-inflammatory mediators such as tumour necrosis factor, presumably to limit self-damaging excessive inflammation. Using viral gene transfer vectors, we are currently investigating the potential of these inhibitors in various models of inflammation in vivo. PMID:12023836

  16. Photodynamic antimicrobial polymers for infection control.

    Directory of Open Access Journals (Sweden)

    Colin P McCoy

    Full Text Available Hospital-acquired infections pose both a major risk to patient wellbeing and an economic burden on global healthcare systems, with the problem compounded by the emergence of multidrug resistant and biocide tolerant bacterial pathogens. Many inanimate surfaces can act as a reservoir for infection, and adequate disinfection is difficult to achieve and requires direct intervention. In this study we demonstrate the preparation and performance of materials with inherent photodynamic, surface-active, persistent antimicrobial properties through the incorporation of photosensitizers into high density poly(ethylene (HDPE using hot-melt extrusion, which require no external intervention except a source of visible light. Our aim is to prevent bacterial adherence to these surfaces and eliminate them as reservoirs of nosocomial pathogens, thus presenting a valuable advance in infection control. A two-layer system with one layer comprising photosensitizer-incorporated HDPE, and one layer comprising HDPE alone is also described to demonstrate the versatility of our approach. The photosensitizer-incorporated materials are capable of reducing the adherence of viable bacteria by up to 3.62 Log colony forming units (CFU per square centimeter of material surface for methicillin resistant Staphylococcus aureus (MRSA, and by up to 1.51 Log CFU/cm(2 for Escherichia coli. Potential applications for the technology are in antimicrobial coatings for, or materials comprising objects, such as tubing, collection bags, handrails, finger-plates on hospital doors, or medical equipment found in the healthcare setting.

  17. ANTIMICROBIAL ACTIVITY OF FEW SELECTED MEDICINAL PLANTS

    Directory of Open Access Journals (Sweden)

    Dash G. K

    2011-01-01

    Full Text Available The petroleum ether, chloroform, methanol and aqueous extracts of leaves of Ageratum conyzoides Linn (Fam: Asteraceae, Argemone mexicana Linn. (Fam: Papaveraceae, Heliotropium indicum Linn (Fam: Boraginaceae and stem barks of Alstonia scholaris (L. R. Brown (Fam: Apocynaceae were screened for their antimicrobial activity against Bacillus subtilis, Stapphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger respectively. The results indicated that the chloroform, methanol and aqueous extracts of all tested plant materials are active against both Gram-positive and Gram-negative bacteria at the tested concentration. The spectrum of activity observed in the present study may be an indicative of the presence of broad spectrum antimicroial compounds in the extracts. Among the tested extracts, methanol extracts of all selected plant materials were found to be more effective than the other extracts under study. Preliminary phytochmical screening of the methanol extracts of selected plant materials primarily revealed presence of alkaloids, tannins and flavonoids. The present work justifies the use of these plant materials for antimicrobial activity as claimed in the folklore remedies.

  18. Facilitating the entry into force and implementation of the amendment to the Convention on the Physical Protection of Nuclear Material: observations, challenges and benefits

    International Nuclear Information System (INIS)

    The Amendment to the Convention on the Physical Protection of Nuclear Material (CPPNM) was adopted in July 2005. The Amendment expands and deepens the effect of the CPPNM of 1980. However, more than nine years after its adoption and despite the perceived threat and recognized need to strengthen the CPPNM dating back some fifteen years ago, the Amendment is still not in force. Entry into force remains a major piece of unfinished business in international efforts to help ensure that nuclear material does not fall into the hands of terrorists or other criminals. Although to some CPPNM States Par ties, the pressing need for the Amendment to enter into force is clear and ts benefits are recognised, further consideration needs to be given to identifying why this has not happened. More particularly, what are the reasons why nearly half of the current CPPNM States Parties, including, those with and without nuclear material and nuclear facilities, have still not joined the Amendment? Also, what challenges do they face in joining and effectively implementing the instrument? The paper seeks to provide answers and identifies some benefits of the Amendment, as well as IAEA assistance available to Member States, upon request, to facilitate the entry into force and implementation of the Amendment. (author)

  19. The impacts of dental filling materials on RapidArc treatment planning and dose delivery: Challenges and solution

    Energy Technology Data Exchange (ETDEWEB)

    Mail, Noor; Al-Ghamdi, S.; Saoudi, A. [Princess Norah Oncology Center, National Guard Health Affairs, Jeddah 21423, Saudi Arabia and King Abdullah International Medical Research Center, Jeddah 21423 (Saudi Arabia); Albarakati, Y.; Ahmad Khan, M.; Saeedi, F.; Safadi, N. [Princess Norah Oncology Center, National Guard Health Affairs, Jeddah 21423 (Saudi Arabia)

    2013-08-15

    Purpose: The presence of high-density material in the oral cavity creates dose perturbation in both downstream and upstream directions at the surfaces of dental filling materials (DFM). In this study, the authors have investigated the effect of DFM on head and neck RapidArc treatment plans and delivery. Solutions are proposed to address (1) the issue of downstream dose perturbation, which might cause target under dosage, and (2) to reduce the upstream dose from DFM which may be the primary source of mucositis. In addition, an investigation of the clinical role of a custom-made plastic dental mold/gutter (PDM) in sparing the oral mucosa and tongue reaction is outlined.Methods: The influence of the dental filling artifacts on dose distribution was investigated using a geometrically well-defined head and neck intensity modulated radiation therapy (IMRT) verification phantom (PTW, Freiberg, Germany) with DFM inserts called amalgam, which contained 50% mercury, 25% silver, 14% tin, 8% copper, and 3% other trace metals. Three RapidArc plans were generated in the Varian Eclipse System to treat the oral cavity using the same computer tomography (CT) dataset, including (1) a raw CT image, (2) a streaking artifacts region, which was replaced with a mask of 10 HU, and (3) a 2 cm-thick 6000 HU virtual filter [a volume created in treatment planning system to compensate for beam attenuation, where the thickness of this virtual filter is based on the measured percent depth dose (PDD) data and Eclipse calculation]. The dose delivery for the three plans was verified using Gafchromic-EBT2 film measurements. The custom-made PDM technique to reduce backscatter dose was clinically tested on four head and neck cancer patients (T3, N1, M0) with DFM, two patients with PDM and the other two patients without PDM. The thickness calculation of the PDM toward the mucosa and tongue was purely based on the measured upstream dose. Patients’ with oral mucosal reaction was clinically examined

  20. The impacts of dental filling materials on RapidArc treatment planning and dose delivery: Challenges and solution

    International Nuclear Information System (INIS)

    Purpose: The presence of high-density material in the oral cavity creates dose perturbation in both downstream and upstream directions at the surfaces of dental filling materials (DFM). In this study, the authors have investigated the effect of DFM on head and neck RapidArc treatment plans and delivery. Solutions are proposed to address (1) the issue of downstream dose perturbation, which might cause target under dosage, and (2) to reduce the upstream dose from DFM which may be the primary source of mucositis. In addition, an investigation of the clinical role of a custom-made plastic dental mold/gutter (PDM) in sparing the oral mucosa and tongue reaction is outlined.Methods: The influence of the dental filling artifacts on dose distribution was investigated using a geometrically well-defined head and neck intensity modulated radiation therapy (IMRT) verification phantom (PTW, Freiberg, Germany) with DFM inserts called amalgam, which contained 50% mercury, 25% silver, 14% tin, 8% copper, and 3% other trace metals. Three RapidArc plans were generated in the Varian Eclipse System to treat the oral cavity using the same computer tomography (CT) dataset, including (1) a raw CT image, (2) a streaking artifacts region, which was replaced with a mask of 10 HU, and (3) a 2 cm-thick 6000 HU virtual filter [a volume created in treatment planning system to compensate for beam attenuation, where the thickness of this virtual filter is based on the measured percent depth dose (PDD) data and Eclipse calculation]. The dose delivery for the three plans was verified using Gafchromic-EBT2 film measurements. The custom-made PDM technique to reduce backscatter dose was clinically tested on four head and neck cancer patients (T3, N1, M0) with DFM, two patients with PDM and the other two patients without PDM. The thickness calculation of the PDM toward the mucosa and tongue was purely based on the measured upstream dose. Patients’ with oral mucosal reaction was clinically examined

  1. Dosimetric consideration for patients with dental filling materials undergoing irradiation of oral cavity using RapidArc: challenges and solution

    Science.gov (United States)

    Mail, Noor; Albarakati, Y.; Khan, M. Ahmad; Saeedi, F.; Safadi, N.; Al-Ghamdi, S.; Saoudi, A.

    2012-03-01

    In this study, we investigate the effect of dental filling materials (DFM) on RapidArcTM treatment plans and delivery in a patient undergoing radiotherapy treatment. The presence of DFM creates uncertainties in CT number and causes long streaking artifacts in the reconstructed images which greatly affect the dose distribution inside the oral cavity. The influence of extensive dental filling artifacts on dose distribution was performed using a geometrically well defined head and neck IMRT verification phantom (PTW, Freiburg, Germany) together with inserts from DFM (Amalgam, 11.3 g/cm3). The phantom was scanned using Siemens SOMATOM Sensation CT simulator (Siemens AG, Germany) under standard head and neck imaging protocol (120 kV, 120 mAs, voxel size 1×1×2 mm3). Three RapidArcTM plans were created in the Varian Eclipse treatment planning System (TPS) to treat oral cavity using the same CT dataset including; 1) raw CT image, 2) streaking artifacts replaced with a mask of 10 HU and 3) 2 cm thick 6000 HU virtual filter (a volume around the teeth in TPS to mimic extra attenuation). The virtual filter thickness optimization was purely based on measured PDD data acquired with DFM and the calculation in Eclipse Planning System using direct beam. The dose delivery and distribution for the three plans was verified using Gafchromic EBT2 (International Specialty Product, Wayne, NJ, USA) film measurements. The artifact mask and virtual filter around the teeth in the planning was found very useful to reduce the discrepancies between the dose plan and delivery. From clinical point of view, these results can be helpful to understand the increase of mucositis in patient having DFM, and further investigation is underway for clinical solution.

  2. Access to new antimicrobial 4-methylumbelliferone derivatives

    Indian Academy of Sciences (India)

    Marwa Zayane; Anis Romdhane; Mejda Daami-Remadi; Hichem Ben Jannet

    2015-09-01

    Synthesis of some novel coumarin esters has been accomplished through iodine-catalyzed method using 4-methylumbelliferone as the starting material. Condensation of hydrazide, which was obtained in two steps from 4-methylumbelliferone, with some arylaldhydes provided hydrazone derivatives, while the reaction with phenylthioisocyanate leads to the thiosemicarbazide that evolved into two new compounds. Finally, condensation reaction of hydrazide with three diketones afforded new pyrrole and pyrazole derivatives. Structures of all synthesized compounds were established on the basis of spectroscopic methods including 1H NMR, 13C NMR and ES-HRMS. They were finally tested for their antimicrobial activity and the structure-activity relationship was discussed.

  3. Safe and Effective Ag Nanoparticles Immobilized Antimicrobial NanoNonwovens

    DEFF Research Database (Denmark)

    Song, Jie; Chen, Menglin; Regina, Viduthalai R.;

    2012-01-01

    Silver nanoparticles (AgNPs) with large surface-to-volume ratio have been widely studied as a valuable material for their strong antimicrobial effect. However, the practical applications of AgNPs in health care and water purification are often hampered by the concern of their toxicity and...

  4. Regulatory challenges in the management of aging of structural materials in nuclear power plants; Retos reguladores en la gestion del envejecimiento de los materiales estructurales de centrales nucleares

    Energy Technology Data Exchange (ETDEWEB)

    Castelo, C.; Mendoza, C.; Mas, E.; Conde, J. M.

    2013-07-01

    The article discusses two major pathways by which a regulatory body, and in particular the CSN, may participate in the acquisition of the necessary knowledge on mechanisms of aging of nuclear structural materials: to participate in forums to share operational experience and R and R project, both nationally and internationally. It notes the importance of this participation to carry out its regulatory function based on the knowledge acquired and the unique challenge of transferring that knowledge to rules and guidelines for their application. The article discusses various R and D projects in which the CSN participates directly. It calls for the presence of regulatory bodies in R and D project funded by the EU and the transfer of the results of such projects to codes, standards or guidelines for feasible implementation. (Author)

  5. The Antimicrobial Properties of Red Algae. The Fight of Your Life: Battling Bacteria.

    Science.gov (United States)

    Case, Christine L.; Warner, Michael

    2001-01-01

    Describes a research project in which a professor and a student collaborated in the screening of macroscopic algae for antimicrobial properties. Includes background information, materials and methods, results, and a discussion of the experiment. (SAH)

  6. Anti-microbial effect of Nigella sativa seed extract against staphylococcal skin Infection

    OpenAIRE

    Rafati, Shiva; Niakan, Mohammad; Naseri, Mohsen

    2014-01-01

    Background: The development of microbial resistance to the existing anti-microbial agents has become a real challenge and a serious problem facing patients suffering from skin infections. Seeds of Nigella sativa have been used for a long time in folk medicine for the treatment of skin infections. Production of new potent agents is urgently needed, especially for hospitals and health care centers. This study is designed to explore anti-microbial effect of extract from the Nigella sativa seeds ...

  7. Antimicrobial resistance: risk associated with antibiotic overuse and initiatives to reduce the problem

    OpenAIRE

    Llor, Carl; Bjerrum, Lars

    2014-01-01

    Antimicrobial resistance is a global public health challenge, which has accelerated by the overuse of antibiotics worldwide. Increased antimicrobial resistance is the cause of severe infections, complications, longer hospital stays and increased mortality. Overprescribing of antibiotics is associated with an increased risk of adverse effects, more frequent re-attendance and increased medicalization of self-limiting conditions. Antibiotic overprescribing is a particular problem in primary care...

  8. Antimicrobial, Antioxidant, and Wound Healing Properties of Kigelia africana (Lam.) Beneth. and Strophanthus hispidus DC.

    OpenAIRE

    Christian Agyare; Anita Serwaa Dwobeng; Nicholas Agyepong; Yaw Duah Boakye; Kwesi Boadu Mensah; Patrick George Ayande; Martin Adarkwa-Yiadom

    2013-01-01

    Microbial infections of various types of wounds are a challenge to the treatment of wounds and wound healing. The study was to investigate antimicrobial and antioxidant properties of methanol leaf and stem bark extracts of Kigelia africana and methanol leaf and root extracts of Strophanthus hispidus and also to determine wound healing properties of the extracts. The antimicrobial activities of the methanol extracts were determined against two Gram-positive and two Gram-negative bacteria and a...

  9. The New Antimicrobial Peptide SpHyastatin from the Mud Crab Scylla paramamosain with Multiple Antimicrobial Mechanisms and High Effect on Bacterial Infection

    Science.gov (United States)

    Shan, Zhongguo; Zhu, Kexin; Peng, Hui; Chen, Bei; Liu, Jie; Chen, Fangyi; Ma, Xiaowan; Wang, Shuping; Qiao, Kun; Wang, Kejian

    2016-01-01

    SpHyastatin was first identified as a new cationic antimicrobial peptide in hemocytes of the mud crab Scylla paramamosain. Based on the amino acid sequences deduced, it was predicted that this peptide was composed of two different functional domains, a proline-rich domain (PRD) and a cysteine-rich domain (CRD). The recombinant product of SpHyastatin displayed potent antimicrobial activities against the human pathogen Staphylococcus aureus and the aquatic animal pathogens Aeromonas hydrophila and Pseudomonas fluorescens. Compared with the CRD of SpHyastatin, the PRD presented better antimicrobial and chitin binding activities, but both regions were essential for allowing SpHyastatin complete antimicrobial activity. The binding properties of SpHyastatin to different microbial surface molecules suggested that this might be an initial and crucial step for performing its antimicrobial activities. Evaluated using propidium iodide uptake assays and scanning electron microscopy images, the antimicrobial mechanism of SpHyastatin was found to be prone to disrupt cell membrane integrity. Interestingly, SpHyastatin exerted its role specifically on the surface of S. aureus and Pichia pastoris whereas it directly killed P. fluorescens through simultaneous targeting the membrane and the cytoplasm, indicating that SpHyastatin could use different antimicrobial mechanisms to kill different species of microbes. As expected, the recombinant SpHyastatin increased the survival rate of crabs challenged with Vibrio parahaemolyticus. In addition, SpHyastatin could modulate some V. parahaemolyticus-responsive genes in S. paramamosain. PMID:27493644

  10. Comparative Evaluation of the Antimicrobial Properties of Glass Ionomer Cements with and without Chlorhexidine Gluconate

    Science.gov (United States)

    Jampanapalli, Sharada Reddy; Konda, Suhasini; Inguva, Hema Chandrika; Chimata, Vamsi Krishna

    2016-01-01

    ABSTRACT Background: Chlorhexidine gluconate is a widely used antimicrobial agent. Adding chlorhexidine and quaternary ammonium compounds to filling materials, such as composite resins, acrylic resins, and glass ionomer cements increases the antibacterial property of restorative materials. This study includes antibacterial property of glass ionomer restorative cements with chlorhexidine gluconate. Aim: The primary objective of our study was to compare the antimicrobial properties of two commercially available glass ionomer cements with and without chlorhexidine gluconate on strains of mutans streptococci. Materials and methods: Two glass ionomers (Fuji II Conventional and Fuji IX) were used. Chlorhexidine gluconate was mixed with glass ionomer cements, and antimicrobial properties against mutans streptococci were assessed by agar diffusion. The tested bacterial strain was inhibited and the antimicrobial properties decreased with time. Results: The highest amount of antimicrobial activity with mean inhibitory zone was found in Fuji II with chlorhexidine gluconate followed by Fuji IX with chlorhexidine gluconate, Fuji II without chlorhexidine gluconate, and Fuji IX without chlorhexidine gluconate. Conclusion: The results of the study confirmed that the addition of 5% chlorhexidine gluconate to Fuji II and Fuji IX glass ionomer cements resulted in a restorative material that had increased antimicrobial properties over the conventional glass ionomer cements alone for Streptococcus mutans. How to cite this article: Yadiki JV, Jampanapalli SR , Konda S, Inguva HC, Chimata VK. Comparative Evaluation of the Antimicrobial Properties of Glass Ionomer Cements with and without Chlorhexidine Gluconate. Int J Clin Pediatr Dent 2016;9(2):99-103. PMID:27365927

  11. Building Student Awareness of Societal Decision-Making Challenges about Energy through the Study of Earth System Data and Innovations in Energy-Related Materials Research

    Science.gov (United States)

    Zalles, D. R.; Acker, J. G.; Berding, M.

    2014-12-01

    Energy literacy requires knowledge about the trade-offs inherent in energy alternatives, about how humans use energy and have choices in how much energy to use, and about what changes to the Earth system are occurring from energy uses. It also requires collaborative decision-making skills coupled with awareness about what values we bring to the table as we negotiate solutions that serve both personal needs and the common good. Coming up with a notion of the common good requires delineating how environmental crises occurring in other parts of the world compare to our own. We also need to understand criteria for judging what might be viable solutions. This presentation describes work that SRI International is carrying out to meet these awareness-building needs. SRI educational researchers created a curriculum that immerses students in studying regional climate change data about California in comparison to global climate change. Students ponder solution energy-related strategies and impact analyses. The curriculum will be described, as will a collaboration between SRI educational researchers and materials scientists. The scientists are designing and testing technologies for producing biofuels and solar power, and for sequestering carbon from coal fired power plants. As they apply principles of science and engineering to test materials intended to meet these energy challenges, they understand that even if the tests prove successful, if there is not economic feasibility or environmental advantage, the technology may not stand as a viable solution. This educator-scientist team is using the Essential Energy Principles and Next Generation Science Standards to articulate milestones along a trajectory of energy learning. The trajectory starts with simple understandings of what energy is and what constitute our energy challenges. It ends with more the types of more sophisticated understandings needed for designing and testing energy technology solutions.

  12. Ability of Laboratory Methods To Predict In-Use Efficacy of Antimicrobial Preservatives in an Experimental Cosmetic

    OpenAIRE

    Farrington, J. K.; Martz, E L; Wells, S. J.; Ennis, C C; Holder, J.; Levchuk, J. W.; Avis, K. E.; Hoffman, P. S.; Hitchins, A. D.; Madden, J M

    1995-01-01

    The abilities of nine antimicrobial systems to preserve an experimental water-based cosmetic formulation were evaluated by six microbiological challenge tests: the U.S. Pharmacopeia test; the British Pharmacopeia test; the Cosmetic, Toiletry, and Fragrance Association test; the rapid screen test; the sequential challenge test; and the post-use test. The antimicrobial systems contained various combinations and amounts of two parabens and a quaternary compound in order to provide a broad range ...

  13. Synthesis of a novel multi N-halamines siloxane precursor and its antimicrobial activity on cotton

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lin; Xu, Yan; Cai, Lu; Zang, Xiong [National Engineering Laboratory for Modern Silk, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, No 199 Renai Road, Industry Park, Suzhou 215021 (China); Li, Zhanxiong, E-mail: lizhanxiong@suda.edu.cn [National Engineering Laboratory for Modern Silk, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, No 199 Renai Road, Industry Park, Suzhou 215021 (China)

    2014-09-30

    A novel N-halamine siloxane antibacterial precursor N-(3-triethoxysilylpropyl)-N′- (N″′-heptylcarbamido-N″-ethyl)-butanediamide (TSHCEB) was synthesized and characterized in this study. The compound was then tethered to the surface of cotton fabrics through covalent ether linkages, followed by exposure to dilute sodium hypochlorite solutions to confer the cotton fabrics antibacterial property. The chemical structure of the monomer was confirmed by FTIR, {sup 1}H NMR and MS, and the surface of the treated cotton fabrics was characterized by FTIR, TGA, SEM, and XPS analysis. The antimicrobial cotton materials were then challenged with Gram-negative Escherichia coli O157:H7 (ATCC 43895) and Gram-positive Staphylococcus aureus (ATCC 6538). Results showed that it provided excellent antimicrobial properties against E. coli O157:H7 and S. aureus via direct contacting for 2–15 min. The controlled release of diverse chlorines was proved by inhibition zone. The chlorine bonded to the coating was stable under standard washing test and routine storage, stability toward UVA irradiation was also investigated, and the lost chlorine could be regenerated by rechlorination. The new N-halamine antibacterial precursor can provide superior antibacterial property within a short contact time.

  14. Synthesis of a novel multi N-halamines siloxane precursor and its antimicrobial activity on cotton

    International Nuclear Information System (INIS)

    A novel N-halamine siloxane antibacterial precursor N-(3-triethoxysilylpropyl)-N′- (N″′-heptylcarbamido-N″-ethyl)-butanediamide (TSHCEB) was synthesized and characterized in this study. The compound was then tethered to the surface of cotton fabrics through covalent ether linkages, followed by exposure to dilute sodium hypochlorite solutions to confer the cotton fabrics antibacterial property. The chemical structure of the monomer was confirmed by FTIR, 1H NMR and MS, and the surface of the treated cotton fabrics was characterized by FTIR, TGA, SEM, and XPS analysis. The antimicrobial cotton materials were then challenged with Gram-negative Escherichia coli O157:H7 (ATCC 43895) and Gram-positive Staphylococcus aureus (ATCC 6538). Results showed that it provided excellent antimicrobial properties against E. coli O157:H7 and S. aureus via direct contacting for 2–15 min. The controlled release of diverse chlorines was proved by inhibition zone. The chlorine bonded to the coating was stable under standard washing test and routine storage, stability toward UVA irradiation was also investigated, and the lost chlorine could be regenerated by rechlorination. The new N-halamine antibacterial precursor can provide superior antibacterial property within a short contact time

  15. Facilitating the entry into force and implementation of the Amendment to the Convention on the Physical Protection of Nuclear Material: Observations, challenges and benefits

    International Nuclear Information System (INIS)

    While the responsibility for nuclear security at the national level rests entirely with each state, international co-operation can be crucial in helping states to fulfil their nuclear security responsibilities and obligations. The central role of the International Atomic Energy Agency (IAEA) in strengthening the nuclear security framework and leading the co-ordination of international activities in the field of nuclear security is now widely recognised. Although much has been done to help states in improving nuclear security, by and under the auspices of the IAEA and other intergovernmental organisations, nuclear terrorism has gained a global recognition as one of the most challenging threats to global security in the 21. century Reports by IAEA member states to the IAEA's Incident and Trafficking Database (ITDB) indicate that nuclear material continues to go missing. Also, too many nuclear facilities are still inadequately protected and sabotage thereof is a threat. Border security remains lax in too many places and the possibility for nuclear smuggling may exist. Attempts by individuals and groups of persons are still made to acquire nuclear material for terrorist and other malicious purposes. The threat of nuclear terrorism remains real. Adopted under the auspices of the IAEA on 8 July 2005, the Amendment to the Convention on the Physical Protection of Nuclear Material ('Amendment') and the existing convention, the Convention on the Physical Protection of Nuclear Material (CPPNM or 'Convention') of 1980, are one of a number of treaties comprising the international legal framework on nuclear security. As will be explained later in the article, the Amendment expands and deepens the effect of the CPPNM. However, more than nine years after its adoption and despite the perceived threat and recognised need to strengthen the CPPNM dating back some 15 years ago, the Amendment is still not in force. Although to some CPPNM states parties, the pressing need for the

  16. Automation of antimicrobial activity screening.

    Science.gov (United States)

    Forry, Samuel P; Madonna, Megan C; López-Pérez, Daneli; Lin, Nancy J; Pasco, Madeleine D

    2016-03-01

    Manual and automated methods were compared for routine screening of compounds for antimicrobial activity. Automation generally accelerated assays and required less user intervention while producing comparable results. Automated protocols were validated for planktonic, biofilm, and agar cultures of the oral microbe Streptococcus mutans that is commonly associated with tooth decay. Toxicity assays for the known antimicrobial compound cetylpyridinium chloride (CPC) were validated against planktonic, biofilm forming, and 24 h biofilm culture conditions, and several commonly reported toxicity/antimicrobial activity measures were evaluated: the 50 % inhibitory concentration (IC50), the minimum inhibitory concentration (MIC), and the minimum bactericidal concentration (MBC). Using automated methods, three halide salts of cetylpyridinium (CPC, CPB, CPI) were rapidly screened with no detectable effect of the counter ion on antimicrobial activity. PMID:26970766

  17. Antimicrobial seafood packaging: a review.

    Science.gov (United States)

    Singh, Suman; Ho Lee, Myung; Park, Lnsik; Shin, Yangjai; Lee, Youn Suk

    2016-06-01

    Microorganisms are the major cause of spoilage in most seafood products; however, only few microbes, called the specific spoilage organisms (SSOs), contribute to the offensive off-flavors associated with seafood spoilage. In food, microbial degradation manifests itself as spoilage, or changes in the sensory properties of a food product, rendering it unsuitable for human consumption. The use of antimicrobial substances can control the general microflora as well as specific microorganisms related to spoilage to provide products with higher safety and better quality. Many antimicrobial compounds have been evaluated in film structures for use in seafood, especially organic acids and their salts, enzymes, bacteriocins; some studies have considered inorganic compounds such as AgSiO2, zinc oxide, silver zeolite, and titanium oxide. The characteristics of some organic antimicrobial packaging systems for seafood and their antimicrobial efficiency in film structures are reviewed in this article. PMID:27478206

  18. Human Antimicrobial Peptides and Proteins

    OpenAIRE

    Guangshun Wang

    2014-01-01

    As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs) play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified ...

  19. Antimicrobial drugs for treating cholera

    OpenAIRE

    Leibovici-Weissman, Ya'ara; Neuberger, Ami; Bitterman, Roni; Sinclair, David; Salam, Mohammed Abdus; Paul, Mical

    2014-01-01

    Background Cholera is an acute watery diarrhoea caused by infection with the bacterium Vibrio cholerae, which if severe can cause rapid dehydration and death. Effective management requires early diagnosis and rehydration using oral rehydration salts or intravenous fluids. In this review, we evaluate the additional benefits of treating cholera with antimicrobial drugs. Objectives To quantify the benefit of antimicrobial treatment for patients with cholera, and determine whether there are diffe...

  20. Nanomaterial with high antimicrobial efficacy--copper/polyaniline nanocomposite.

    Science.gov (United States)

    Bogdanović, Una; Vodnik, Vesna; Mitrić, Miodrag; Dimitrijević, Suzana; Škapin, Srečo D; Žunič, Vojka; Budimir, Milica; Stoiljković, Milovan

    2015-01-28

    This study explores different mechanisms of antimicrobial action by designing hybrid nanomaterials that provide a new approach in the fight against resistant microbes. Here, we present a cheap copper-polyaniline (Cu-PANI) nanocomposite material with enhanced antimicrobial properties, prepared by simple in situ polymerization method, when polymer and metal nanoparticles are produced simultaneously. The copper nanoparticles (CuNPs) are uniformly dispersed in the polymer and have a narrow size distribution (dav = 6 nm). We found that CuNPs and PANI act synergistically against three strains, Escherichia coli, Staphylococcus aureus, and Candida albicans, and resulting nanocomposite exhibits higher antimicrobial activity than any component acting alone. Before using the colony counting method to quantify its time and concentration antimicrobial activity, different techniques (UV-visible spectroscopy, transmission electron microscopy, scanning electron microscope, field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectrophotometry, and inductively coupled plasma optical emission spectrometry) were used to identify the optical, structural, and chemical aspects of the formed Cu-PANI nanocomposite. The antimicrobial activity of this nanocomposite shows that the microbial growth has been fully inhibited; moreover, some of the tested microbes were killed. Atomic force microscopy revealed dramatic changes in morphology of tested cells due to disruption of their cell wall integrity after incubation with Cu-PANI nanocomposite. PMID:25552193

  1. Challenge and Strategy of Chinese Textile Fiber Material%我国纺织纤维原料面临的挑战及应对策略

    Institute of Scientific and Technical Information of China (English)

    姚穆

    2011-01-01

    Challenge and strategy of Chinese textile fiber material were introduced. Challenge of Chinese textile industry material shortage was analyzed. It is considered that now Chinese textile industry are facing new transformation and upgrading period. Our idea should be changed and horizons should be broadened. Industry chain should be extended forward and backward. From final product design, production, market and service to raw material breeding, production and provision, all should be paid attention to. Differential fiber, high performance fiber and new functional fiber should be adopted widely. New technology should be used including siro spinning, sirofil spinning, parallel spinning, embodied compound spinning et al,filament should be used as acompanying spinning,blending or fasciated spinning et al fully in spinning short fiber yarn. Waste textile should be reused to boost textile industry stable development.%阐述我国纺织纤维原料面临的挑战及应对策略.分析了我国纺织工业面临原料紧缺的严峻挑战,认为:当前我国纺织工业正面临着新的转型升级期,应转变观念、开拓视野,加速产业链向前后两个方向的延伸,既关注最终产品的设计、生产、市场和服务化,又关注原料的育种、生产、供应;放手采用差剐化、高性能、新功能纤维原料;运用赛络纺、赛络菲尔纺、平行纺、嵌入式复合纺等新技术,在短纤维纺纱同时,充分利用长丝纤维伴纺、混纺、包缠纺等;注重废弃纺织品再生利用,以促进纺织工业的稳定发展.

  2. Antimicrobial stewardship programs in health care systems.

    Science.gov (United States)

    MacDougall, Conan; Polk, Ron E

    2005-10-01

    Antimicrobial stewardship programs in hospitals seek to optimize antimicrobial prescribing in order to improve individual patient care as well as reduce hospital costs and slow the spread of antimicrobial resistance. With antimicrobial resistance on the rise worldwide and few new agents in development, antimicrobial stewardship programs are more important than ever in ensuring the continued efficacy of available antimicrobials. The design of antimicrobial management programs should be based on the best current understanding of the relationship between antimicrobial use and resistance. Such programs should be administered by multidisciplinary teams composed of infectious diseases physicians, clinical pharmacists, clinical microbiologists, and infection control practitioners and should be actively supported by hospital administrators. Strategies for changing antimicrobial prescribing behavior include education of prescribers regarding proper antimicrobial usage, creation of an antimicrobial formulary with restricted prescribing of targeted agents, and review of antimicrobial prescribing with feedback to prescribers. Clinical computer systems can aid in the implementation of each of these strategies, especially as expert systems able to provide patient-specific data and suggestions at the point of care. Antibiotic rotation strategies control the prescribing process by scheduled changes of antimicrobial classes used for empirical therapy. When instituting an antimicrobial stewardship program, a hospital should tailor its choice of strategies to its needs and available resources. PMID:16223951

  3. Antimicrobial activity of different endodontic sealers: An in vitro evaluation

    Directory of Open Access Journals (Sweden)

    Saha S

    2010-01-01

    Full Text Available Background: Microbes are considered as the primary etiological agents in endodontic diseases. The ways of reducing these agents are root canal debridement, antimicrobial irrigants, and antibacterial filling materials. But the complexity of the pulp canal system presents a problem for chemomechanical preparation. One of the factors determining the success of endodontic treatment is the sealing material with a potent bactericidal effect. Aim: The aim of the present study was to assess the antimicrobial activity of endodontic sealers of different bases - in vitro. Materials and Method: The antimicrobial activity of three root canal sealers (endomethasone, AH 26, and apexit was evaluated against seven strains of bacteria at various time intervals using the agar diffusion test. The freshly mixed sealers were placed in prepared wells of agar plates inoculated with the test microorganisms. The plates were incubated for 24, 48, 72 hours, and 7 and 15 days. The mean zones of inhibition were measured. Statistical Analysis: All statistical analysis was performed using the SPSS 13 statistical software version. The analysis of variance (ANOVA, post-hoc Bonferroni test, and paired t test were performed to reveal the statistical significance. Results: Statistically significant zones of bacterial growth inhibition were observed in descending order of antimicrobial activity: endomethasone, AH 26, and apexit. Conclusion: Zinc oxide eugenol based root canal sealer produced largest inhibitory zones followed in decreasing order by epoxy resin based sealer and least by calcium hydroxide based root canal sealer.

  4. Antimicrobial azobenzene compounds and their potential use in biomaterials

    Science.gov (United States)

    Sessa, L.; Concilio, S.; Iannelli, P.; De Santis, F.; Porta, A.; Piotto, S.

    2016-04-01

    We recently synthesized a class of active compounds with azobenzene structure [1] and lowest in silico toxicity values. The antimicrobial activity of these molecules and their thermal stability are very promising and indicate that they may have interesting and therapeutically significant applications. This work aims to develop new materials with antibacterial and antifungal activity inserting different percentages of synthetic antimicrobial azo compounds in commercial polymer matrices. We realized thin films using solvent casting and melt compounding techniques. The obtained materials retained the proprieties of the pure matrices. This means that azo dye dissolved in the matrix does not influence the thermal behavior and the morphology of the material. Tested films exhibited the capability to inhibit biofilms formation of S. aureus and C. albicans. Spectrophotometric investigation of the azo compound released from the polymer matrices confirmed that the realized materials might be interesting for biomedical tools, antibacterial surfaces, and films for active packaging.

  5. Testing methods for antimicrobial activity of TiO2 photocatalyst

    Directory of Open Access Journals (Sweden)

    Markov Siniša L.

    2014-01-01

    Full Text Available In recent years, a lot of commercial TiO2 photocatalyst products have been developed and extensively studied for prospective and safe antimicrobial application in daily life, medicine, laboratories, food and pharmaceutical industry, waste water treatments and in development of new self-cleaning and antimicrobial materials, surfaces and paints. This paper reviews the studies published worldwide on killing microorganisms, methods for testing the antimicrobial activity, light sources and intensities, as well as calculation methods usually used when evaluating the antimicrobial properties of the TiO2-based products. Additionally, some strengths and weaknesses of the available methods for testing the antimicrobial activity of TiO2 photocatalyst products have been pointed out.[Projekat Ministarstva nauke Republike Srbije, br. III45008

  6. Distinct Profiling of Antimicrobial Peptide Families

    KAUST Repository

    Khamis, Abdullah M.

    2014-11-10

    Motivation: The increased prevalence of multi-drug resistant (MDR) pathogens heightens the need to design new antimicrobial agents. Antimicrobial peptides (AMPs) exhibit broad-spectrum potent activity against MDR pathogens and kills rapidly, thus giving rise to AMPs being recognized as a potential substitute for conventional antibiotics. Designing new AMPs using current in-silico approaches is, however, challenging due to the absence of suitable models, large number of design parameters, testing cycles, production time and cost. To date, AMPs have merely been categorized into families according to their primary sequences, structures and functions. The ability to computationally determine the properties that discriminate AMP families from each other could help in exploring the key characteristics of these families and facilitate the in-silico design of synthetic AMPs. Results: Here we studied 14 AMP families and sub-families. We selected a specific description of AMP amino acid sequence and identified compositional and physicochemical properties of amino acids that accurately distinguish each AMP family from all other AMPs with an average sensitivity, specificity and precision of 92.88%, 99.86% and 95.96%, respectively. Many of our identified discriminative properties have been shown to be compositional or functional characteristics of the corresponding AMP family in literature. We suggest that these properties could serve as guides for in-silico methods in design of novel synthetic AMPs. The methodology we developed is generic and has a potential to be applied for characterization of any protein family.

  7. Interaction between antimicrobial peptides and mycobacteria.

    Science.gov (United States)

    Gutsmann, Thomas

    2016-05-01

    Mycobacteria can cause different severe health problems, including tuberculosis (TB). The treatment of TB with conventional antibiotics is successful, however, the number of multi-drug and extensively-drug resistant Mycobacterium tuberculosis strains increases. Moreover, many classical antimycobacterial antibiotics have severe side effects. Therefore, antimicrobial peptides (AMPs) seem to be good candidates for new therapeutic strategies. On the one hand AMPs can be used as a single drug or in combination with conventional antibiotics to directly kill mycobacteria, or on the other hand to act as immunstimulatory agents. This review summarizes the findings on the role of endogenous human AMPs being involved in TB, the antimycobacterial activity of various AMPs, and the molecular modes of action. Most active AMPs interact with the mycobacterial cell envelope and in particular with the mycomembrane and the plasma membrane. The mycomembrane is a very rigid membrane probably leading to a lower activity of the AMPs against mycobacteria as compared to other Gram-negative or Gram-positive bacteria. For some AMPs also other targets have been identified. Because of the complex environment of intracellular mycobacteria being trapped in the phagosome, within the macrophage, within the granuloma, within the lung, the external administration of AMPs in the latent phase of TB is a challenge. However, in the acute phase the AMPs can attack mycobacteria in a direct way. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. PMID:26851776

  8. CZTSSe: Materials and Physics Challenges

    Science.gov (United States)

    Gunawan, Oki

    2011-03-01

    Thin-film photovoltaic (PV) technologies led by CdTe and Cu(In,Ga) Se 2 (CIGS) are enjoying growing market share, due to their high performance and cost competitiveness, in the quest for renewable energy for the future. However the reliance on non-earth abundant elements tellurium and indium in these technologies presents a potential obstacle to ultimate terawatt deployment. We recently demonstrated kesterite Cu 2 ZnSn(Se,S)4 (CZTSSe) solar cells, comprised of the earth abundant metals copper, zinc and tin, with world record efficiency of 9.7%. In this talk we present a comprehensive device characterization study that pinpoints the key performance bottlenecks in these cells. We find strong buffer-absorber interface recombination and low minority carrier lifetimes that limit the open circuit voltage and a high and diverging device series resistance at lower temperature that suggests a blocking back contact that may limit the fill factor. These findings help to identify key areas for improvement for these CZTSSe cells in the pursuit of a high performance terawatt-scalable PV technology. In collaboration with Teodor K. Todorov, Aaron Barkhouse, Kejia Wang, David B. Mitzi, Supratik Guha, IBM T J Watson Research Center.

  9. Editorial of the Special Issue Antimicrobial Polymers

    Directory of Open Access Journals (Sweden)

    Iolanda Francolini

    2013-09-01

    Full Text Available The special issue “Antimicrobial Polymers” includes research and review papers concerning the recent advances on preparation of antimicrobial polymers and their relevance to industrial settings and biomedical field. Antimicrobial polymers have recently emerged as promising candidates to fight microbial contamination onto surfaces thanks to their interesting properties. In this special issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with antimicrobial agents or synthesis of polymers bearing antimicrobial moieties, were discussed. The future application of these polymers either in industrial or healthcare settings could result in an extremely positive impact not only at the economic level but also for the improvement of quality of life.

  10. A new vision of the post-NIST civil infrastructure program: the challenges of next-generation construction materials and processes

    Science.gov (United States)

    Wu, H. Felix; Wan, Yan

    2014-03-01

    Our nation's infrastructural systems are crumbling. The deteriorating process grows over time. The physical aging of these vital facilities and the remediation of their current critical state pose a key societal challenge to the United States. Current sensing technologies, while well developed in controlled laboratory environments, have not yet yielded tools for producing real-time, in-situ data that are adequately comprehensible for infrastructure decision-makers. The need for advanced sensing technologies is national because every municipality and state in the nation faces infrastructure management challenges. The need is critical because portions of infrastructure are reaching the end of their life-spans and there are few cost-effective means to monitor infrastructure integrity and to prioritize the renovation and replacement of infrastructure elements. New advanced sensing technologies that produce cost-effective inspection and real-time monitoring data, and that can also help or aid in meaningful interpretation of the acquired data, therefore will enhance the safety in regard to the public on structural integrity by issuing timely and accurate alert data for effective maintenance to avoid disasters happening. New advanced sensing technologies also allow more informed management of infrastructural investments by avoiding premature replacement of infrastructure and identifying those structures in need of immediate action to prevent from catastrophic failure. Infrastructure management requires that once a structural defect is detected, an economical and efficient repair be made. Advancing the technologies of repairing infrastructure elements in contact with water, road salt, and subjected to thermal changes requires innovative research to significantly extend the service life of repairs, lower the costs of repairs, and provide repair technologies that are suitable for a wide range of conditions. All these new technologies will provide increased lifetimes

  11. Antimicrobial resistance in bacteria from horses: Epidemiology of antimicrobial resistance.

    Science.gov (United States)

    Maddox, T W; Clegg, P D; Williams, N J; Pinchbeck, G L

    2015-11-01

    Antimicrobial resistance poses a significant threat to the continued successful use of antimicrobial agents for the treatment of bacterial infections. While the epidemiology of antimicrobial resistance in bacteria from man has been studied extensively, less work has been undertaken in companion animals, particularly horses. Methicillin-resistant Staphylococcus aureus has been identified as a cause of infections, with a low prevalence of nasal carriage by horses in the community but higher for hospitalised horses. Molecular characterisation has shown methicillin-resistant Staphylococcus aureus strains either to be predominantly of types associated with horses or of sequence type ST398. Antimicrobial-resistant Escherichia coli (including multidrug-resistant and extended spectrum β-lactamase-producing isolates) have caused infections and been documented in faecal carriage by horses, with many significant resistance mechanisms identified. More sporadic reports and molecular characterisation exist for resistance in other bacteria such as enterococci, Salmonella, Acinetobacter and Pseudomonas species. Limited work has been undertaken evaluating risk factors and much of the epidemiology of antimicrobial resistance in bacteria from horses remains to be determined. PMID:26084443

  12. Antimicrobial Effects of Quercus Brantii Fruits on Bacterial Pathogens

    Directory of Open Access Journals (Sweden)

    Issa Sadeghian

    2012-08-01

    Full Text Available Background: In recent years, a number of antibiotics have lost their effectiveness due to the development of resistant strains, mostly through the expression of resistance genes.Objectives: The aim of the present study was to investigate the antimicrobial property of Quercus brantii fruits and compare its effects with some current antibiotics.Materials and Methods: The antimicrobial activities of an ethanol extract of Q. brantii (Oak fruits (brown cortex: B.C and white core: W.C were tested in vitro against eight reference strains of enteric pathogenic bacteria. The antimicrobial activities of the extracts were examined based on the disc diffusion method. The results were evaluated as inhibition zones around the discs impregnated with B.C and W.C extracts at different concentrations (2 to 10 %.Results: The antibacterial effect of the B.C ethanolic extract on Escherichia coli was significant and had a concentration-related effect, although there was no significant effect found on Helicobacter pylori. The W.C ethanolic extract has a high antimicrobial effect on Streptococcus pyogenes; at the same time significant antibacterial activity occurred against H pylori. Comparisons between the antimicrobial activities of these extracts (B.C and W.C and standard antibiotics; gentamicin, colistin, and methicillin, showed that in the most commonly tested bacteria the antibacterial activity of these extracts was even greater than with the antibiotics. Analysis of the extracts components by gas chromatography, showed that tannins and phenolic compounds could be responsible for these antimicrobial activities.Conclusions: The results of this study showed that different parts of Q. brantii have antimicrobial activity against gastrointestinal bacterial pathogens. These antimicrobial activities, in almost all cases, were greater than with standard antibiotics..--------------------------------------------------------------------------------Implication for health

  13. Antimicrobial Peptides from Plants

    Science.gov (United States)

    Tam, James P.; Wang, Shujing; Wong, Ka H.; Tan, Wei Liang

    2015-01-01

    Plant antimicrobial peptides (AMPs) have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs) of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic), lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms. PMID:26580629

  14. Antimicrobial Peptides from Plants

    Directory of Open Access Journals (Sweden)

    James P. Tam

    2015-11-01

    Full Text Available Plant antimicrobial peptides (AMPs have evolved differently from AMPs from other life forms. They are generally rich in cysteine residues which form multiple disulfides. In turn, the disulfides cross-braced plant AMPs as cystine-rich peptides to confer them with extraordinary high chemical, thermal and proteolytic stability. The cystine-rich or commonly known as cysteine-rich peptides (CRPs of plant AMPs are classified into families based on their sequence similarity, cysteine motifs that determine their distinctive disulfide bond patterns and tertiary structure fold. Cystine-rich plant AMP families include thionins, defensins, hevein-like peptides, knottin-type peptides (linear and cyclic, lipid transfer proteins, α-hairpinin and snakins family. In addition, there are AMPs which are rich in other amino acids. The ability of plant AMPs to organize into specific families with conserved structural folds that enable sequence variation of non-Cys residues encased in the same scaffold within a particular family to play multiple functions. Furthermore, the ability of plant AMPs to tolerate hypervariable sequences using a conserved scaffold provides diversity to recognize different targets by varying the sequence of the non-cysteine residues. These properties bode well for developing plant AMPs as potential therapeutics and for protection of crops through transgenic methods. This review provides an overview of the major families of plant AMPs, including their structures, functions, and putative mechanisms.

  15. Antimicrobial peptides in annelids

    Directory of Open Access Journals (Sweden)

    A Tasiemski

    2008-06-01

    Full Text Available Gene encoded antimicrobial peptides (AMPs are widely distributed among living organisms including plants, invertebrates and vertebrates. They constitute important effectors of the innate immune response by exerting multiple roles as mediators of inflammation with impact on epithelial and inflammatory cells influencing diverse processes such as cytokine release, cell proliferation, angiogenesis, wound healing, chemotaxis and immune induction. In invertebrates, most of the data describe the characterization and/or the function of AMPs in the numerically and economically most representative group which are arthropods. Annelids are among the first coelomates and are therefore of special phylogenetic interest. Compared to other invertebrate groups, data on annelid’s immunity reveal heavier emphasis on the cellular than on the humoral response suggesting that immune defense of annelids seems to be principally developed as cellular immunity.This paper gives an overview of the variety of AMPs identified in the three classes of annelids, i.e. polychaetes, oligochaetes and achaetes. Their functions, when they have been studied, in the humoral or cellular response of annelids are also mentioned.

  16. Antimicrobial peptides in crustaceans

    Directory of Open Access Journals (Sweden)

    RD Rosa

    2010-11-01

    Full Text Available Crustaceans are a large and diverse invertebrate animal group that mounts a complex and efficient innate immune response against a variety of microorganisms. The crustacean immune system is primarily related to cellular responses and the production and release of important immune effectors into the hemolymph. Antimicrobial proteins and/or peptides (AMPs are key components of innate immunity and are widespread in nature, from bacteria to vertebrate animals. In crustaceans, 15 distinct AMP families are currently recognized, although the great majority (14 families comes from members of the order Decapoda. Crustacean AMPs are generally cationic, gene-encoded molecules that are mainly produced by circulating immune-competent cells (hemocytes or are derived from unrelated proteins primarily involved in other biological functions. In this review, we tentatively classified the crustacean AMPs into four main groups based on their amino acid composition, structural features and multi-functionality. We also attempted to summarize the current knowledge on their implication both in an efficient response to microbial infections and in crustacean survival.

  17. Antimicrobials in urogenital infections.

    Science.gov (United States)

    Wagenlehner, Florian M E; Wullt, Björn; Perletti, Gianpaolo

    2011-12-01

    Urinary tract infections (UTIs) and male genital infections are amongst the most prevalent infections. A prudent antibiotic policy therefore has a large impact on society. The clinical classification in uncomplicated cystitis, uncomplicated pyelonephritis, complicated UTI and genital infections is useful, also for the right choice of antibiotic treatment. In this regard pharmacokinetic and pharmacodynamic aspects have to be considered. Nowadays in uncomplicated cystitis antibiotics exclusively reserved for this indication are preferred, such as fosfomycin trometamol, nitrofurantoin and pivmecillinam, in order to reduce antibiotic pressure in this extremely frequent entity. In complicated UTI a broad bacterial spectrum has to be considered. Different antibiotic substances should be used for treatment, such as penicillins, with β-lactamase inhibitors, cephalosporins or carbapenems, fluoroquinolones, aminoglycosides or cotrimoxazole, if tested susceptible. For genital infections the pharmacokinetic properties of the antibiotics should especially be considered, such as in prostatitis, where mainly fluoroquinolones and macrolides show sufficient pharmacokinetic parameters for treatment of bacterial infections. Furthermore in genital infections fastidious organisms, such as Chlamydia or Mycoplasma spp. have to be considered with respect to their antimicrobial susceptibility. PMID:22019184

  18. Antimicrobial Activity of Protamine against Oral Microorganisms.

    Science.gov (United States)

    Kim, Yeon-Hee; Kim, Sang Moo; Lee, Si Young

    2015-01-01

    Protamine is an arginine-rich polycationic protein extracted from sperm cells of vertebrates including fishes such as salmon. The purpose of this study was to investigate the suppressive effects of protamine on the growth of oral pathogens for possible usage in dental materials. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were determined by the microdilution method. Twelve strains of oral viridans streptococci, Actinomyces naeslundii, Actinomyces odontolyticus, Enterococcus faecalis, Lactobacillus acidophilus, Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, Porphyromonas gingivalis and Candida albicans were suppressed by protamine. MIC and MBC values were between 0.009 ~ 20 mg/mL and 0.019 ~ 80 mg/mL, respectively. The bactericidal activities of protamine against susceptible bacterial species were dependent on the concentration of protamine and incubation time. Based on the results of this study, protamine would be a useful compound for the development of antimicrobial agents against oral pathogens in dental materials. PMID:26699859

  19. Antimicrobial stewardship in small animal veterinary practice

    DEFF Research Database (Denmark)

    Guardabassi, Luca; Prescott, John F

    2015-01-01

    Despite the increasing recognition of the critical role for antimicrobial stewardship in preventing the spread of multidrug-resistant bacteria, examples of effective antimicrobial stewardship programs are rare in small animal veterinary practice. This article highlights the basic requirements for...

  20. Polysaccharide-based biomaterials with antimicrobial and antioxidant properties

    Directory of Open Access Journals (Sweden)

    Véronique Coma

    2013-01-01

    Full Text Available Active packaging is one of the responses to the recent food-borne microbial outbreaks and to the consumer’s demand for high quality food and for packaging that is more advanced and creative than what is currently offered. Moreover, with the recent increase in ecological awareness associated with the dramatic decrease in fossil resources, research has turned towards the elaboration of more natural materials. This paper provides a short review of biomaterials exhibiting antimicrobial and antioxidant properties for applications in food preservation. The two main concepts of active biopackaging materials are briefly introduced. The different polysaccharides potentially used in packaging materials are then presented associated with a brief overview of research works related to biopackaging, exhibiting notably antimicrobial or antioxidant properties. Finally, future trends such as the release-on-demand of bioactive agents are discussed.

  1. Editorial of the Special Issue Antimicrobial Polymers

    OpenAIRE

    Iolanda Francolini; Antonella Piozzi

    2013-01-01

    The special issue “Antimicrobial Polymers” includes research and review papers concerning the recent advances on preparation of antimicrobial polymers and their relevance to industrial settings and biomedical field. Antimicrobial polymers have recently emerged as promising candidates to fight microbial contamination onto surfaces thanks to their interesting properties. In this special issue, the main strategies pursued for developing antimicrobial polymers, including polymer impregnation with...

  2. Antimicrobial resistance of thermophilic Campylobacter

    DEFF Research Database (Denmark)

    Aarestrup, Frank Møller; Engberg, J.

    2001-01-01

    Campylobacter has become the leading cause of zoonotic enteric infections in developed and developing countries world-wide. Antimicrobial resistance has emerged among Campylobacter mainly as a consequence of the use of antimicrobial agents in food animal production. Resistance to drugs of choice...... for the treatment of infections, macrolides and fluoroquinolones has emerged as a clinical problem and interventions to reduce this are recommended. Resistance to fluoroquinolones and macrolides is mediated by chromosomal mutations. Resistance to other relevant antimicrobial agents, mediated by...... acquired resistance genes, has not become widespread so far. However, resistance genes originating from both Gram-positive and Gram-negative bacterial species have been found, showing the potential for acquired resistance to emerge in Campylobacter....

  3. Antimicrobial Packaging for Extending the Shelf Life of Bread-A Review.

    Science.gov (United States)

    Jideani, V A; Vogt, K

    2016-06-10

    Antimicrobial packaging is an important form of active packaging that can release antimicrobial substances for enhancing the quality and safety of food during extended storage. It is in response to consumers demand for preservative-free food as well as more natural, disposable, biodegradable, and recyclable food-packaging materials. The potential of a combination of allyl isothiocyanate and potassium sorbate incorporated into polymers in providing the needed natural antimicrobial protection for bread products is discussed. The role of double extrusion process as a means for obtaining a homogeneous mix of the sorbate into the polymer (polyethylene or ethylenevinyalcohol), is highlighted. PMID:25603190

  4. Evaluation of antimicrobial activity of the crude ethanol extract of Eugenia uniflora L. leaves

    OpenAIRE

    F. C. PIMENTA; L.M.F. TRESVENZOL; J.R. Paula; S. M.T. SABóIA-MORAIS; T. S. FIúZA

    2009-01-01

    Eugenia unifl ora L. is a tree whose leaves are used in popular medicine as an antihypertensive, antimicrobial drug, in the treatment of bronchitis, infl uenza and as an antipyretic. This paper reports the antimicrobial activity of a crude ethanol extract of E. unifl ora L. leaves. The crude extract was prepared from material collected in Goiânia, Goiás (Brazil), dried, pulverized and subjected to phytochemical screening. The antimicrobial activity was tested against spore-forming and non-spo...

  5. Uses of antimicrobial genes from microbial genome

    Science.gov (United States)

    Sorek, Rotem; Rubin, Edward M.

    2013-08-20

    We describe a method for mining microbial genomes to discover antimicrobial genes and proteins having broad spectrum of activity. Also described are antimicrobial genes and their expression products from various microbial genomes that were found using this method. The products of such genes can be used as antimicrobial agents or as tools for molecular biology.

  6. Non-thermal plasma technology for the development of antimicrobial surfaces: a review

    Science.gov (United States)

    Nikiforov, Anton; Deng, Xiaolong; Xiong, Qing; Cvelbar, U.; DeGeyter, N.; Morent, R.; Leys, Christophe

    2016-05-01

    Antimicrobial coatings are in high demand in many fields including the biomaterials and healthcare sectors. Within recent progress in nanoscience and engineering at the nanoscale, preparation of nanocomposite films containing metal nanoparticles (such as silver nanoparticles, copper nanoparticles, zinc oxide nanoparticles) is becoming an important step in manufacturing biomaterials with high antimicrobial activity. Controlled release of antibiotic agents and eliminating free nanoparticles are of equal importance for engineering antimicrobial nanocomposite materials. Compared to traditional chemical ‘wet’ methods, plasma deposition and plasma polymerization are promising approaches for the fabrication of nanocomposite films with the advantages of gas phase dry processes, effective use of chemicals and applicability to various substrates. In this article, we present a short overview of state-of-the-art engineering of antimicrobial materials based on the use of non-thermal plasmas at low and atmospheric pressure.

  7. Cholesterol suppresses antimicrobial effect of statins

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Haeri

    2015-12-01

    Full Text Available Objective(s:Isoprenoid biosynthesis is a key metabolic pathway to produce a wide variety of biomolecules such as cholesterol and carotenoids, which target cell membranes. On the other hand, it has been reported that statins known as inhibitors of isoprenoid biosynthesis and cholesterol lowering agents, may have a direct antimicrobial effect on the some bacteria. The exact action of statins in microbial metabolism is not clearly understood. It is possible that statins inhibit synthesis or utilization of some sterol precursor necessary for bacterial membrane integrity. Accordingly, this study was designed in order to examine if statins inhibit the production of a compound, which can be used in the membrane, and whether cholesterol would replace it and rescue bacteria from toxic effects of statins. Materials and Methods: To examine the possibility we assessed antibacterial effect of statins with different classes; lovastatin, simvastatin, and atorvastatin, alone and in combination with cholesterol on two Gram-positive (Staphylococcus aureus and Enterococcus faecalis and two Gram-negative (Pseudomonas aeruginosa and Escherichia coli bacteria using gel diffusion assay. Results: Our results showed that all of the statins except for lovastatin had significant antibacterial property in S. aureus, E. coli, and Enter. faecalis. Surprisingly, cholesterol nullified the antimicrobial action of effective statins in statin-sensitive bacteria. Conclusion: It is concluded that statins may deprive bacteria from a metabolite responsible for membrane stability, which is effectively substituted by cholesterol.

  8. Osteomyelitis: a current challenge

    Directory of Open Access Journals (Sweden)

    Luciana Souza Jorge

    2010-06-01

    Full Text Available Over the last 30 years, the pathogenesis of osteomyelitis has almost been totally elucidated, and many factors responsible for the persistence of this infection have been identified. Numerous antimicrobial agents with distinct spectrums of action, pharmacokinetics, and pharmacodynamics have been used in its treatment. Surgical techniques, including muscle grafts, the Ilizarov technique, and antibiotic bone cements, have been applied. However, bone infections are still a challenge. Despite the importance of isolation and identification of microorganisms to determine the antimicrobial treatment of bone infections, there are few systematic national studies about the etiological profile of these diseases. This article describes the current knowledge of osteomyelitis and summarizes published national data based on the experience of different Orthopedic and Traumatology Services. In general, S. aureus was described as an important etiological agent; however, the difference in design of national studies makes a comparison between the prevalence of bone infection, the associated risk factors, and the different therapeutic approaches difficult. In conclusion, effort is necessary in order to stimulate systematic national studies in different Orthopedics and Traumatology Services to obtain a better consensus on preventive measures and therapies of bone infections.

  9. Green and biodegradable composite films with novel antimicrobial performance based on cellulose.

    Science.gov (United States)

    Wu, Yuehan; Luo, Xiaogang; Li, Wei; Song, Rong; Li, Jing; Li, Yan; Li, Bin; Liu, Shilin

    2016-04-15

    In order to obtain a safe and biodegradable material with antimicrobial properties from cellulose for food packaging, we presented a facile way to graft chitosan onto the oxidized cellulose films. The obtained films had a high transparent property of above 80% transmittance, excellent barrier properties against oxygen and antimicrobial properties against Escherichia coli and Staphylococcus aureus. The antimicrobial properties, mechanical properties, and water vapor permeability of composites are essential characteristics in determining their applicability as food-packaging materials. Moreover, using a sausage model, it was shown that the composites exhibited better performance than traditional polyethylene packaging material and demonstrated good potential as food packaging materials. The results presented a new insight into the development of green materials for food packaging. PMID:26616947

  10. Physicochemical and antimicrobial properties of copaiba oil: implications on product quality control

    OpenAIRE

    Renata G. Fonseca; Francisco M. Barros; Miriam A. Apel; Gilsane L. von Poser; Jo&#o L. Andriolli; Pedro C. Campos Filho; Dhierlate F. Sousa; Ivon P. Lobo; Aline O. Conceiç&#o

    2015-01-01

    Background. The copaiba oil is a common natural product used in cosmetic industry and as a nutraceutical product. However, lack of quality control and scarce knowledge about its antimicrobial activity is a point of concern. The proposal of this study was to investigate the physicochemical properties and the antimicrobial activity of five commercial brands of copaiba oil. Material and methods. Acidity and ester index, refractory index, solubility in alcohol, and thin layer chromatography w...

  11. Chemical composition, antimicrobial activity and antiviral activity of essential oil of Carum copticum from Iran

    OpenAIRE

    Reza Kazemi Oskuee; Javad Behravan; Mohammad Ramezani

    2011-01-01

    Objectives: Evaluation of therapeutic effects of Carum copticum (C. copticum) has been the subject of several studies in recent years. Thymol the major component of C. copticum is a widely known anti-microbial agent. In this study, the antibacterial and anti viral activities of essential oil of C. copticum fruit were determined. Materials and Methods: Essential oil of C. copticum was analyzed by means of gas chromatography-mass spectrometry (GC-MS). The antimicrobial activity of the oil wa...

  12. ANTIMICROBIAL PROPERTIES OF ARECA CATECHU (ARECA NUT) HUSK EXTRACTS AGAINST COMMON ORAL PATHOGENS

    OpenAIRE

    Maria Bobby Cyriac; Vidya Pai; Ipe Varghese; Manjula Shantaram; Maji Jose

    2012-01-01

    The husk fibres of Areca catechu (areca nut) are reported to be used by the people of rural areas of Dakshina Kannada, Karnataka for cleaning their teeth. The beneficial effects of these plant materials are not scientifically proven, so the study was carried out to estimate the antimicrobial properties of A.catechu against common oral pathogens. These antimicrobial properties in addition to mechanical cleansing property of the fibers of areca nut could improve the oral health. Alcoholic an...

  13. Physical, Antioxidant and Antimicrobial Characteristics of Carboxymethyl Cellulose Edible Film Cooperated with Clove Essential Oil

    OpenAIRE

    Ramin Khaksar; Alireza Dashipour; Hedayat Hosseini; Saeedeh Shojaee-Aliabadi; Kiandokht Ghanati

    2014-01-01

    Background: Carboxymethyl cellulose (CMC) is one of the most common cellulose derivatives. It has many applications such as edible films and coating. Antioxidant and antimicrobial of essential oils and their direct or indirect usage in foods have been investigated. This study focuses on the physical, chemical, antioxidant and antimicrobial characteristics of CMC edible film incorporated with clove essential oils (CEO). Materials and Methods: In this experimental study, CMC edible films wit...

  14. In vitro antimicrobial status of methanolic extract of Citrus sinensis Linn. fruit peel

    OpenAIRE

    Anju Dhiman; Arun Nanda; Sayeed Ahmad; Balasubramanian Narasimhan

    2012-01-01

    Aim : The present investigation evaluated the antimicrobial potential of methanolic extract of Citrus sinensis Linn. (Rutaceae) fruit peel. There is a basis for the traditional use of this plant for local health remedies. Materials and Methods: The antimicrobial activity of methanolic extract of C. sinensis fruit peel was tested against three bacterial and two fungal strains. Turbidimetric or tube dilution method and paper disc diffusion method were followed. Results are expressed as mean ± s...

  15. CNS SPECIES AND ANTIMICROBIAL RESISTANCE IN CLINICAL AND SUBCLINICAL BOVINE MASTITIS

    OpenAIRE

    Persson Waller, K.; Aspán, A; Nyman, A.; Persson, Y.; Grönlund Andersson, U.

    2011-01-01

    Abstract Coagulase-negative staphylococci (CNS) are often associated with bovine mastitis. Knowledge about the relative importance of specific CNS species in different types of mastitis, and differences in antimicrobial resistance among CNS species is, however, scarce. Therefore, the aims of this study were to compare prevalence and antimicrobial susceptibility of CNS species in clinical and subclinical mastitis using material from two national surveys. Overall, S. chromogenes and ...

  16. Antimicrobial Property of Extracts of Indian Lichen against Human Pathogenic Bacteria

    OpenAIRE

    Srivastava, Priya; Upreti, D. K.; Dhole, T. N.; Srivastava, Apurva K.; Nayak, Meghanand T

    2013-01-01

    Context. Usnea ghattensis G. Awasthi (Usneaceae) endemic fruticose lichen found growing luxuriantly in Northern Western Ghats of India, it also contains Usnic acid as a major chemical and tested against some human pathogenic bacteria. Objective. To explore antimicrobial properties of Usnea ghattensis against some human pathogenic bacteria. Materials and Methods. The lichen was extracted in acetone, methanol, and ethanol. In vitro antimicrobial activity was tested initially by Kirby-Bauer tech...

  17. Antimicrobial and cytotoxic effects of phosphoric acid solution compared to other root canal irrigants

    OpenAIRE

    PRADO, Maíra; Emmanuel João Nogueira Leal da SILVA; Thais Mageste DUQUE; ZAIA, Alexandre Augusto; Ferraz, Caio Cezar Randi; de Almeida, José Flávio Affonso; GOMES, Brenda Paula Figueiredo de Almeida

    2015-01-01

    Phosphoric acid has been suggested as an irrigant due to its effectiveness in removing the smear layer. Objectives : The purpose of this study was to compare the antimicrobial and cytotoxic effects of a 37% phosphoric acid solution to other irrigants commonly used in endodontics. Material and Methods : The substances 37% phosphoric acid, 17% EDTA, 10% citric acid, 2% chlorhexidine (solution and gel), and 5.25% NaOCl were evaluated. The antimicrobial activity was tested against Candida albican...

  18. An effective zinc phthalocyanine derivative for photodynamic antimicrobial chemotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Zhuo, E-mail: zchen@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Zhou, Shanyong; Chen, Jincan [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Li, Linsen [Department of Biochemistry, Shenyang Medical College, Shenyang, Liaoning 110034 (China); Hu, Ping; Chen, Song [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China); Huang, Mingdong, E-mail: mhuang@fjirsm.ac.cn [State Key Laboratory of Structural Chemistry and Danish-Chinese Centre for Proteases and Cancer, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2014-08-01

    Bacterial infection is a common clinical problem. The emergence of antibiotic resistant bacteria posts a severe challenge to medical practice worldwide. Photodynamic antimicrobial chemotherapy (PACT) uses laser light at specific wavelength to activate oxygen molecule in the human tissue into reactive oxygen species as antimicrobial agent. This activation of oxygen by laser light is mediated through a photosensitizer. Two key properties for potent photosensitizer are its absorbance of light in the infrared region (630–700 nm), which promotes tissue penetration depth, and the selective accumulation on bacteria instead of human tissue. We herein report a zinc phthalocyanine derivative, pentalysine β-carbonylphthalocyanine zinc (ZnPc-(Lys){sub 5}) and its antimicrobial effects in vitro and in an animal infection model. This photosensitizer has strong capability to kill bacteria at 670 nm. Chemically, it is a water-soluble and cationic photosensitizer carrying positive charge under physiological pH, and can specifically target to bacteria which usually bears negative charges on its surface. Compared with anionic ZnPc counterparts, ZnPc-(Lys){sub 5} shows a higher phototoxicity toward bacteria. PACT studies of ZnPc-(Lys){sub 5} in experimental infection animal model showed a significant bacteria inhibition compared to controls, and high selectivity of ZnPc-(Lys){sub 5} toward bacteria. These findings suggest ZnPc-(Lys){sub 5} is a promising antimicrobial photosensitizer for the treatment of infectious diseases. - Highlights: • Photodynamic antimicrobial chemotherapy (PACT) with water-soluble zinc phthalocyanine derivative offers a promising measure to deal with antibiotic resistance of bacteria. • The use of portable LED light sources that are battery-powered and with low cost may make possible the deployment of systems that can be used for wound decontamination. • ZnPc-(Lys){sub 5} is a potent photosensitizer for treatment of infectious diseases.

  19. An effective zinc phthalocyanine derivative for photodynamic antimicrobial chemotherapy

    International Nuclear Information System (INIS)

    Bacterial infection is a common clinical problem. The emergence of antibiotic resistant bacteria posts a severe challenge to medical practice worldwide. Photodynamic antimicrobial chemotherapy (PACT) uses laser light at specific wavelength to activate oxygen molecule in the human tissue into reactive oxygen species as antimicrobial agent. This activation of oxygen by laser light is mediated through a photosensitizer. Two key properties for potent photosensitizer are its absorbance of light in the infrared region (630–700 nm), which promotes tissue penetration depth, and the selective accumulation on bacteria instead of human tissue. We herein report a zinc phthalocyanine derivative, pentalysine β-carbonylphthalocyanine zinc (ZnPc-(Lys)5) and its antimicrobial effects in vitro and in an animal infection model. This photosensitizer has strong capability to kill bacteria at 670 nm. Chemically, it is a water-soluble and cationic photosensitizer carrying positive charge under physiological pH, and can specifically target to bacteria which usually bears negative charges on its surface. Compared with anionic ZnPc counterparts, ZnPc-(Lys)5 shows a higher phototoxicity toward bacteria. PACT studies of ZnPc-(Lys)5 in experimental infection animal model showed a significant bacteria inhibition compared to controls, and high selectivity of ZnPc-(Lys)5 toward bacteria. These findings suggest ZnPc-(Lys)5 is a promising antimicrobial photosensitizer for the treatment of infectious diseases. - Highlights: • Photodynamic antimicrobial chemotherapy (PACT) with water-soluble zinc phthalocyanine derivative offers a promising measure to deal with antibiotic resistance of bacteria. • The use of portable LED light sources that are battery-powered and with low cost may make possible the deployment of systems that can be used for wound decontamination. • ZnPc-(Lys)5 is a potent photosensitizer for treatment of infectious diseases

  20. Animation of Antimicrobial Resistance

    Medline Plus

    Full Text Available ... CVM produced material may be copied, reproduced, and distributed as long as FDA's Center for Veterinary ... Monitoring System About NARMS Bacteria (NARMS) NARMS at Work Reports ...

  1. PLANT PRODUCTS AS ANTIMICROBIAL AGENTS

    OpenAIRE

    Ionela Daciana Ciocan; Ion Bara

    2007-01-01

    Plants produce a diverse array of secondary metabolites, many of which have antimicrobial activity.Some of this compounds are constitutive, existing in healthy plants in their biologically active forms. Others such as cyanogenic glycosides and glucosinolates, occur as inactive precursors and are activated in response to tissue damage or pathogen attack.

  2. An Antimicrobial Susceptibility Management System

    OpenAIRE

    Farmer, James J.; O'Donnell, Edward D.

    1981-01-01

    A computerized system is described which is used to store, manipulate and retrieve antimicrobial susceptibility data in the clinical microbiology lab. Features include facilitated input of susceptibility data, rapid generation of reports, realtime access to data, and enhanced retrieval of information for Infection Control.

  3. Helical Antimicrobial Sulfono- {gamma} -AApeptides

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yaqiong; Wu, Haifan; Teng, Peng; Bai, Ge; Lin, Xiaoyang; Zuo, Xiaobing; Cao, Chuanhai; Cai, Jianfeng

    2015-06-11

    Host-defense peptides (HDPs) such as magainin 2 have emerged as potential therapeutic agents combating antibiotic resistance. Inspired by their structures and mechanism of action, herein we report the fi rst example of antimicrobial helical sulfono- γ - AApeptide foldamers. The lead molecule displays broad-spectrum and potent antimicrobial activity against multi-drug-resistant Gram- positive and Gram-negative bacterial pathogens. Time-kill studies and fl uorescence microscopy suggest that sulfono- γ -AApeptides eradicate bacteria by taking a mode of action analogous to that of HDPs. Clear structure - function relationships exist in the studied sequences. Longer sequences, presumably adopting more-de fi ned helical structures, are more potent than shorter ones. Interestingly, the sequence with less helical propensity in solution could be more selective than the stronger helix-forming sequences. Moreover, this class of antimicrobial agents are resistant to proteolytic degradation. These results may lead to the development of a new class of antimicrobial foldamers combating emerging antibiotic-resistant pathogens.

  4. Antimicrobial Activity of Resveratrol Analogues

    Directory of Open Access Journals (Sweden)

    Malik Chalal

    2014-06-01

    Full Text Available Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew. Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold. The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups and antimicrobial activity.

  5. Antimicrobial Polymers with Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Humberto Palza

    2015-01-01

    Full Text Available Metals, such as copper and silver, can be extremely toxic to bacteria at exceptionally low concentrations. Because of this biocidal activity, metals have been widely used as antimicrobial agents in a multitude of applications related with agriculture, healthcare, and the industry in general. Unlike other antimicrobial agents, metals are stable under conditions currently found in the industry allowing their use as additives. Today these metal based additives are found as: particles, ions absorbed/exchanged in different carriers, salts, hybrid structures, etc. One recent route to further extend the antimicrobial applications of these metals is by their incorporation as nanoparticles into polymer matrices. These polymer/metal nanocomposites can be prepared by several routes such as in situ synthesis of the nanoparticle within a hydrogel or direct addition of the metal nanofiller into a thermoplastic matrix. The objective of the present review is to show examples of polymer/metal composites designed to have antimicrobial activities, with a special focus on copper and silver metal nanoparticles and their mechanisms.

  6. ANTIMICROBIAL RESISTANCE TRENDS IN SALMONELLA

    Science.gov (United States)

    Background: Since the early 1990’s there has been increasing awareness and concern regarding the development of antimicrobial resistance among bacteria of public health significance. Reports targeting zoonotic bacteria, and in particular Salmonella species, suggest that resistance is trending upwar...

  7. Antimicrobial activity of Rhodobryum ontariense

    OpenAIRE

    Sabovljević Aneta; Pejin Boris; Vujičić Milorad; Ćirić Ana; Glamočlija Jasmina; Soković Marina; Sabovljević Marko

    2012-01-01

    The antimicrobial activity of dimethyl sulfoxide extract of moss Rhodobryum ontariense (Kindb.) Kindb. was evaluated by microdilution method against eight bacterial (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhimurium, Enterobacter cloacae, Listeria monocytogens, Bacillus cereus, Micrococcus flavus and Staphylococcus aureus) and five fungal species (Aspergillus versicolor, Aspergillus fumigatus, Penicillium funiculosum, Penicillium ochrochloron and Trichoderma viride). The ...

  8. Antimicrobial activity of resveratrol analogues.

    Science.gov (United States)

    Chalal, Malik; Klinguer, Agnès; Echairi, Abdelwahad; Meunier, Philippe; Vervandier-Fasseur, Dominique; Adrian, Marielle

    2014-01-01

    Stilbenes, especially resveratrol and its derivatives, have become famous for their positive effects on a wide range of medical disorders, as indicated by a huge number of published studies. A less investigated area of research is their antimicrobial properties. A series of 13 trans-resveratrol analogues was synthesized via Wittig or Heck reactions, and their antimicrobial activity assessed on two different grapevine pathogens responsible for severe diseases in the vineyard. The entire series, together with resveratrol, was first evaluated on the zoospore mobility and sporulation level of Plasmopara viticola (the oomycete responsible for downy mildew). Stilbenes displayed a spectrum of activity ranging from low to high. Six of them, including the most active ones, were subsequently tested on the development of Botrytis cinerea (fungus responsible for grey mold). The results obtained allowed us to identify the most active stilbenes against both grapevine pathogens, to compare the antimicrobial activity of the evaluated series of stilbenes, and to discuss the relationship between their chemical structure (number and position of methoxy and hydroxy groups) and antimicrobial activity. PMID:24918540

  9. Antimicrobial activity of Securidaca longipedunculata.

    Science.gov (United States)

    Ajali, U; Chukwurah, B K C

    2004-11-01

    The folk herbal uses of Securidaca longipedunculata in the treatment of diarrhea, boils, gonorrhea, and cough prompted phytochemical analyses and antimicrobial activity screening of extracts of the root. Some flavonoids isolated showed activity against many micro-organisms. These flavonoids were isolated using chromatographic methods. PMID:15636189

  10. Antimicrobial Susceptibility Pattern of Enterococci Isolated From Patients in Tehran

    Directory of Open Access Journals (Sweden)

    Saderi

    2015-11-01

    Full Text Available Background Enterococci are one of the most common nosocomial pathogens and the emergence of multidrug-resistant strains has been increasing. Objectives We studied the antimicrobial susceptibility of enterococci isolated from different clinical specimens of patients in Tehran. Materials and Methods From the beginning of April 2013 to the end of June 2013, a total of 146 enterococci were isolated from the Pars General Hospital in Tehran. The antimicrobial susceptibility pattern of the isolates against ampicillin, clindamaycin, ciprofloxacin, erythromycin, levofloxacin, linezolid, nitrofurantoin, tetracycline, and vancomycin was determined using the disk diffusion method according to the guidelines of clinical laboratory standards institute (CLSI. Results The rates of resistance were high to clindamycin, tetracycline, and erythromycin (97.2%, 89%, and 74.5%, respectively; moderate to ciprofloxacilin and levofloxacilin (40.6% and 36.4%, respectively; and low to ampicillin and nitrofurantoin (13.8% and 3.5%, respectively. All isolates were linezolid sensitive. Vancomycin-resistant enterococci (VRE accounted for 9.6% of the isolates. Conclusions VRE and a high rate of resistance to some of antimicrobial agents were found among the enterococci isolated from patients in Tehran. These findings highlight the importance of regular supervision of antimicrobial susceptibilities.

  11. Synthesis and Antimicrobial Activity of a Silver-Hydroxyapatite Nanocomposite

    Directory of Open Access Journals (Sweden)

    Marcos Díaz

    2009-01-01

    Full Text Available A silver-hydroxyapatite nanocomposite has been obtained by a colloidal chemical route and subsequent reduction process in H2/Ar atmosphere at 350∘C. This material has been characterized by TEM, XRD, and UV-Visible spectroscopy, showing the silver nanoparticles (∼65 nm supported onto the HA particles (∼130 nm surface without a high degree of agglomeration. The bactericidal effect against common Gram-positive and Gram-negative bacteria has been also investigated. The results indicated a high antimicrobial activity for Staphylococcus aureus, Pneumococcus and Escherichia coli, so this material can be a promising antimicrobial biomaterial for implant and reconstructive surgery applications.

  12. Antimicrobial factor from Bacillus amyloliquefaciens inhibits Paenibacillus larvae, the causative agent of American foulbrood.

    Science.gov (United States)

    Benitez, Lisianne Brittes; Velho, Renata Voltolini; de Souza da Motta, Amanda; Segalin, Jéferson; Brandelli, Adriano

    2012-03-01

    Bacillus amyloliquefaciens LBM 5006 produces an antimicrobial factor active against Paenibacillus larvae, a major honeybee pathogen. The antagonistic effect and the mode of action of the antimicrobial factor were investigated. The antibacterial activity was produced starting at mid-logarithmic growth phase, reaching its maximum during the stationary phase. Exposure of cell suspensions of P. larvae to this antimicrobial resulted in loss of cell viability and reduction in optical density associated with cell lysis. Scanning electron microscopy showed damaged cell envelope and loss of protoplasmic material. The antimicrobial factor was stable for up to 80°C, but it was sensitive to proteinase K and trypsin. Mass spectrometry analysis indicates that the antimicrobial activity is associated with iturin-like peptides. The antimicrobial factor from B. amyloliquefaciens LBM 5006 showed a bactericidal effect against P. larvae cells and spores. This is the first report on iturin activity against P. larvae. This antimicrobial presents potential for use in the control of American foulbrood disease. PMID:21858429

  13. Biofilm induced tolerance towards antimicrobial peptides.

    Directory of Open Access Journals (Sweden)

    Anders Folkesson

    Full Text Available Increased tolerance to antimicrobial agents is thought to be an important feature of microbes growing in biofilms. We address the question of how biofilm organization affects antibiotic susceptibility. We established Escherichia coli biofilms with differential structural organization due to the presence of IncF plasmids expressing altered forms of the transfer pili in two different biofilm model systems. The mature biofilms were subsequently treated with two antibiotics with different molecular targets, the peptide antibiotic colistin and the fluoroquinolone ciprofloxacin. The dynamics of microbial killing were monitored by viable count determination, and confocal laser microscopy. Strains forming structurally organized biofilms show an increased bacterial survival when challenged with colistin, compared to strains forming unstructured biofilms. The increased survival is due to genetically regulated tolerant subpopulation formation and not caused by a general biofilm property. No significant difference in survival was detected when the strains were challenged with ciprofloxacin. Our data show that biofilm formation confers increased colistin tolerance to cells within the biofilm structure, but the protection is conditional being dependent on the structural organization of the biofilm, and the induction of specific tolerance mechanisms.

  14. Polymyxins: Antimicrobial susceptibility concerns and therapeutic options

    Directory of Open Access Journals (Sweden)

    V Balaji

    2011-01-01

    Full Text Available The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.

  15. Antimicrobial evaluation of Huilliche plant medicine used to treat wounds

    DEFF Research Database (Denmark)

    Mølgaard, Per; Holler, Jes Gitz; Asar, Betül;

    2011-01-01

    Ethnopharmacological relevanceThe traditional use of 40 plant species used for treatment of wounds and associated infections by the Huilliche people of Chile was evaluated against bacterial and fungal human pathogens, especially including wound pathogens. Materials and methodsThe extracts were......). ResultsThirteen of the plant species have interesting antimicrobial activities, with that of Acaena argentea, Aristotelia chilensis, Blechnum chilense, Francoa appendiculta, Gevuina avellana and Laureliopsis philippiana being the most noteworthy. ConclusionsThe findings in the manuscript support the...

  16. Synergistic Antimicrobial Effect of Tribulus terrestris and Bitter Almond Extracts

    OpenAIRE

    Hamid Abtahi; Ali Ghazavi; Masode Karimi

    2014-01-01

    Background: The antimicrobial effects of the extracts of different kinds of plants have been demonstrated in several studies. However, no study has been conducted so far on the synergistic effects of two herbal extracts on their germicidal effects. In this study, in addition to antibacterial effects of the aqueous, methanol or ethanol extracts of Tribulus terrestris and bitter almond on some bacteria, the synergistic effects of the extracts of these two plants were also evaluated. Material...

  17. Polysaccharide-based biomaterials with antimicrobial and antioxidant properties

    OpenAIRE

    Véronique Coma

    2013-01-01

    Active packaging is one of the responses to the recent food-borne microbial outbreaks and to the consumer’s demand for high quality food and for packaging that is more advanced and creative than what is currently offered. Moreover, with the recent increase in ecological awareness associated with the dramatic decrease in fossil resources, research has turned towards the elaboration of more natural materials. This paper provides a short review of biomaterials exhibiting antimicrobial and antiox...

  18. A new active and antimicrobial package for preservation of vegetables

    OpenAIRE

    Taboada Rodríguez, Amaury

    2013-01-01

    [ENG] The food packaging industry is demanding new packages able to improve the quality of the packed products. In this regard some of the problems to be solved are the recyclable and compostable character of the materials, the antimicrobial properties of some substances to be involved in the packaging system and the optimum control of the internal atmosphere in the package. As a solution for these problems a new flow-pack active packaging design was proposed to be developed in this investiga...

  19. ANTIMICROBIAL ACTIVITY OF WHITE AND PINK NELUMBO NUCIFERA GAERTN FLOWERS

    OpenAIRE

    D.BRINDHA, D.ARTHI

    2013-01-01

    Nelumbo nucifera Gaertn (Family: Nelumbonaceae), medicinally versatile and used as an important raw material of age-old traditional medical practices like Ayurveda and folk medicine. Bioassays for antimicrobial activities were carried out using hydroethanolic extract of both white and pink flowers of Nelumbo nucifera Gaertn plant. Both the flower extracts were tested against five important bacterial strains and two fungal strains. Further, Minimum Inhibitory Concentration (MIC) was evaluated ...

  20. Emerging antimicrobial resistance pattern of Helicobacter pylori in central Gujarat

    OpenAIRE

    H B Pandya; Harihar Har Agravat; J S Patel; NRK Sodagar

    2014-01-01

    Background: Antimicrobial resistance is a growing problem in H. pylori treatment. The study was intended to evaluate the prevalence of resistance amongst 80 H.pylori isolates cultured from biopsy taken during routine endoscopies in 2008-2011. Materials and Methods: 855 gastro duodenal biopsies were collected and cultured on H.pylori selective medium (containing Brucella agar and Columbia agar (Hi media), with Skirrow′s supplement (antibiotic supplement) and 7% human blood cells). H.pylori was...

  1. Comparative Antimicrobial Activities of Aerosolized Sodium Hypochlorite, Chlorine Dioxide, and Electrochemically Activated Solutions Evaluated Using a Novel Standardized Assay

    OpenAIRE

    Thorn, R. M. S.; G.M. Robinson; Reynolds, D M

    2013-01-01

    The main aim of this study was to develop a standardized experimental assay to enable differential antimicrobial comparisons of test biocidal aerosols. This study represents the first chlorine-matched comparative assessment of the antimicrobial activities of aerosolized sodium hypochlorite, chlorine dioxide, and electrochemically activated solution (ECAS) to determine their relative abilities to decontaminate various surface-associated health care-relevant microbial challenges. Standard micro...

  2. The challenges of green nanotechnology

    OpenAIRE

    Miguel de la Guardia

    2014-01-01

    Nanomaterials have great impacts on life sciences; however, these advanced materials may induce inadvertant consequences. Thus, this editorial will highlight the futuristic challenges ingreen nanotechnology.

  3. Assessing the antimicrobial activity of zinc oxide thin films using disk diffusion and biofilm reactor

    International Nuclear Information System (INIS)

    The electronic and chemical properties of semiconductor materials may be useful in preventing growth of microorganisms. In this article, in vitro methods for assessing microbial growth on semiconductor materials will be presented. The structural and biological properties of silicon wafers coated with zinc oxide thin films were evaluated using atomic force microscopy, X-ray photoelectron spectroscopy, and MTT viability assay. The antimicrobial properties of zinc oxide thin films were established using disk diffusion and CDC Biofilm Reactor studies. Our results suggest that zinc oxide and other semiconductor materials may play a leading role in providing antimicrobial functionality to the next-generation medical devices

  4. A molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide

    Science.gov (United States)

    Rodina, N. P.; Yudenko, A. N.; Terterov, I. N.; Eliseev, I. E.

    2013-08-01

    Antimicrobial peptides are a class of small, usually positively charged amphiphilic peptides that are used by the innate immune system to combat bacterial infection in multicellular eukaryotes. Antimicrobial peptides are known for their broad-spectrum antimicrobial activity and thus can be used as a basis for a development of new antibiotics against multidrug-resistant bacteria. The most challengeous task on the way to a therapeutic use of antimicrobial peptides is a rational design of new peptides with enhanced activity and reduced toxicity. Here we report a molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide D51. This peptide was earlier designed by Loose et al. using a linguistic model of natural antimicrobial peptides. Molecular dynamics simulation of the peptide folding in explicit solvent shows fast formation of two antiparallel beta strands connected by a beta-turn that is confirmed by circular dichroism measurements. Obtained from simulation amphipatic conformation of the peptide is analysed and possible mechanism of it's interaction with bacterial membranes together with ways to enhance it's antibacterial activity are suggested.

  5. A molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide

    International Nuclear Information System (INIS)

    Antimicrobial peptides are a class of small, usually positively charged amphiphilic peptides that are used by the innate immune system to combat bacterial infection in multicellular eukaryotes. Antimicrobial peptides are known for their broad-spectrum antimicrobial activity and thus can be used as a basis for a development of new antibiotics against multidrug-resistant bacteria. The most challengeous task on the way to a therapeutic use of antimicrobial peptides is a rational design of new peptides with enhanced activity and reduced toxicity. Here we report a molecular dynamics and circular dichroism study of a novel synthetic antimicrobial peptide D51. This peptide was earlier designed by Loose et al. using a linguistic model of natural antimicrobial peptides. Molecular dynamics simulation of the peptide folding in explicit solvent shows fast formation of two antiparallel beta strands connected by a beta-turn that is confirmed by circular dichroism measurements. Obtained from simulation amphipatic conformation of the peptide is analysed and possible mechanism of it's interaction with bacterial membranes together with ways to enhance it's antibacterial activity are suggested

  6. Recent Advances on Multi-Parameter Flow Cytometry to Characterize Antimicrobial Treatments.

    Science.gov (United States)

    Léonard, Lucie; Bouarab Chibane, Lynda; Ouled Bouhedda, Balkis; Degraeve, Pascal; Oulahal, Nadia

    2016-01-01

    The investigation on antimicrobial mechanisms is a challenging and crucial issue in the fields of food or clinical microbiology, as it constitutes a prerequisite to the development of new antimicrobial processes or compounds, as well as to anticipate phenomenon of microbial resistance. Nowadays it is accepted that a cells population exposed to a stress can cause the appearance of different cell populations and in particular sub-lethally compromised cells which could be defined as viable but non-culturable (VBNC). Recent advances on flow cytometry (FCM) and especially on multi-parameter flow cytometry (MP-FCM) provide the opportunity to obtain high-speed information at real time on damage at single-cell level. This review gathers MP-FCM methodologies based on individual and simultaneous staining of microbial cells employed to investigate their physiological state following different physical and chemical antimicrobial treatments. Special attention will be paid to recent studies exploiting the possibility to corroborate MP-FCM results with additional techniques (plate counting, microscopy, spectroscopy, molecular biology techniques, membrane modeling) in order to elucidate the antimicrobial mechanism of action of a given antimicrobial treatment or compound. The combination of MP-FCM methodologies with these additional methods is namely a promising and increasingly used approach to give further insight in differences in microbial sub-population evolutions in response to antimicrobial treatments. PMID:27551279

  7. A Study of Anti-Microbial Effect of Pycnocycla Spinosa's Fruit Extracts

    Directory of Open Access Journals (Sweden)

    M. Jalali, Ph.D.

    2007-09-01

    Full Text Available Background and purpose: Infectious diseases account for approximately one-half of all deaths in tropical country. In developed country, despite the progress made on the control of disease, incidence of epidemics due to drug resistant microorganisms and unknown diseases spreading microbes pose enormous public health concerns. On the other hand, in spite of improvements in food production hygiene, food safety is increasingly an important health issue. There is, therefore, still a need for new antimicrobial agent to reduce or eliminate foodborne pathogen as well as food spoilage microorganisms. Historically, plants play a major role in primary health-care as therapeutic remedies in developing countries. The screening of plant extracts has been of great interest to scientists for the discovery of new drugs effective in the treatment of infectious disease. Umbelleferea is known to be a potential source for the antimicrobial agents. The present study attempts to investigate the antimicrobial activity of Pycnocycla spinosa as a member of Umbelleferea against selected microorganisms.Materials and Methods: The plants were collected from Isfahan and different solvent extracts of plants were prepared. Then, the antimicrobial activity of extract was determined, using disk diffusion method. The minimal inhibitory concentration (MIC was determined by tube dilution method.Results: Results demonstrated that different extracts of plants indicate antimicrobial activity against bucillu subtilis, aspergiluse niger and candida albicans. Generally, the antimicrobial activity of the plant’s fruit extracts is considered medium.Conclusion: Pycnocycla spinosa fruit's extract showed medium antimicrobial activity. Hydroalcoholic extract of the fruit demonstrated higher antimicrobial activity. This may reflect a low concentration of active components in extracts. Further studies are needed to investigate antimicrobial activity of the plant's essential oil and other parts

  8. Antimicrobial particulate silver coatings on stainless steel implants for fracture management

    International Nuclear Information System (INIS)

    We have used particulate silver coating on stainless steel to prevent in vivo bacterial infection. Stainless steel is commonly used as an implant material for fracture management. The antimicrobial use of silver has been well documented and studied, therefore the novelty of this research is the use of a particulate coating as well as facing the real world challenges of a fracture repair implant. The variable parameters for applying the coating were time of deposition, silver solution concentration, voltage applied, heat treatment temperature between 400 and 500 °C and time. The resultant coating is shown to be non-toxic to human osteoblasts using an MTT assay for proliferation and SEM images for morphology. In vitro silver release studies of various treatments were done using simulated body fluid. The bactericidal effects were tested by challenging the coatings with Pseudomonas aeruginosa in a bioreactor and compared against uncoated stainless steel. A 13-fold reduction in bacteria was observed at 24 h and proved to be statistically significant. - Highlights: ► Processing of particulate silver coating that are strongly adherent on SS surface. ► Optimized the amount of silver that is sufficient to reduce bacterial colonization but non-toxic to human bone tissue. ► The adhesion strength of silver was sufficient to survive industrial sterilization steps used for fracture management devices.

  9. In vitro evaluation of the antimicrobial activity of some endodontic sealers

    Directory of Open Access Journals (Sweden)

    Denise Piotto LEONARDI

    2009-12-01

    Full Text Available Introduction: When performing endodontic treatment, the dentalsurgeon must find ways to eliminate or reduce the microorganismssituated in the root canal in cases of pulpal necrosis. Objective: Toanalyze the antimicrobial action of Endofill, Sealer 26, AHPlus andAcroseal endodontic sealers. Material and methods: Evaluation wasmade by Agar diffusion method in plates previously inoculated with thefollowing microorganisms: E. coli, E. faecalis, B. cereus and S. aureus. The zones of inhibition were measured after 48 hours of incubation at 37°C. Results: Acroseal sealer showed no antimicrobial activity against E. coli and E. faecalis and it showed moderate activity against B. cereus and S. aureus; AHPlus and Endofill showed high activity mainly against E. coli; Sealer 26 showed moderate activity against all of the microorganisms used. Conclusion: The majority of endodontic sealers have showed antimicrobial activity against the microorganisms used. AHPlus and Endofill sealers were the ones that showed greater antimicrobial activity.

  10. Extraction and functionalization of bagasse cellulose nanofibres to Schiff-base based antimicrobial membranes.

    Science.gov (United States)

    Bansal, Monica; Chauhan, Ghanshyam S; Kaushik, Anupama; Sharma, Avantika

    2016-10-01

    The work reported in this paper involves synthesis of a nanocellulose/chitosan composite and its further modification to antimicrobial films. Bagasse, an easily available biowaste, was used as source to extract nanocellulose fibres (CNFs) by subjecting it to mechanical and chemical treatments including alkaline steam explosion and high shear homogenization. The CNFs were subjected to periodate oxidation to obtain nanocellulose dialdehyde (CDA). The aldehyde groups of CDA were reacted with amino groups of chitosan to form Schiff-base. The resulting CDA/chitosan composite fibres were characterized at various steps. The fibres were then cast into films using cellulose acetate as a binder. The films have good physical strength. The composite films show excellent antimicrobial properties when tested against Staphylococcus aureus and Escherichia coli. Such antimicrobial films have potential applications in the formation of antimicrobial packaging material. PMID:27316771

  11. Size-dependent antimicrobial effects of novel palladium nanoparticles.

    Science.gov (United States)

    Adams, Clara P; Walker, Katherine A; Obare, Sherine O; Docherty, Kathryn M

    2014-01-01

    Investigating the interactions between nanoscale materials and microorganisms is crucial to provide a comprehensive, proactive understanding of nanomaterial toxicity and explore the potential for novel applications. It is well known that nanomaterial behavior is governed by the size and composition of the particles, though the effects of small differences in size toward biological cells have not been well investigated. Palladium nanoparticles (Pd NPs) have gained significant interest as catalysts for important carbon-carbon and carbon-heteroatom reactions and are increasingly used in the chemical industry, however, few other applications of Pd NPs have been investigated. In the present study, we examined the antimicrobial capacity of Pd NPs, which provides both an indication of their usefulness as target antimicrobial compounds, as well as their potency as potential environmental pollutants. We synthesized Pd NPs of three different well-constrained sizes, 2.0 ± 0.1 nm, 2.5 ± 0.2 nm and 3.1 ± 0.2 nm. We examined the inhibitory effects of the Pd NPs and Pd(2+) ions toward gram negative Escherichia coli (E. coli) and gram positive Staphylococcus aureus (S. aureus) bacterial cultures throughout a 24 hour period. Inhibitory growth effects of six concentrations of Pd NPs and Pd(2+) ions (2.5 × 10(-4), 10(-5), 10(-6), 10(-7), 10(-8), and 10(-9) M) were examined. Our results indicate that Pd NPs are generally much more inhibitory toward S. aureus than toward E. coli, though all sizes are toxic at ≥ 10(-5) M to both organisms. We observed a significant difference in size-dependence of antimicrobial activity, which differed based on the microorganism tested. Our work shows that Pd NPs are highly antimicrobial, and that fine-scale (<1 nm) differences in size can alter antimicrobial activity. PMID:24465824

  12. Cholic acid derivatives: novel antimicrobials.

    Science.gov (United States)

    Savage, P B; Li, C

    2000-02-01

    Mimics of squalamine and polymyxin B (PMB) have been prepared from cholic acid in hope of finding new antimicrobial agents. The squalamine mimics include the polyamine and sulphate functionalities found in the parent antibiotic, however, the positions relative to the steroid nucleus have been exchanged. The PMB mimics include the conservation of functionality among the polymyxin family of antibiotics, the primary amine groups and a hydrophobic chain. Although the squalamine and PMB mimics are morphologically dissimilar, they display similar activities. Both are simple to prepare and demonstrate broad spectrum antimicrobial activity against Gram-negative and Gram-positive organisms. Specific examples may be inactive alone, yet effectively permeabilise the outer membranes of Gram-negative bacteria rendering them sensitive to hydrophobic antibiotics. Problems associated with some of the squalamine and PMB mimics stem from their haemolytic activity and interactions with serum proteins, however, examples exist without these side effects which can sensitise Gram-negative bacteria to hydrophobic antibiotics. PMID:11060676

  13. Antimicrobial Peptides from Marine Proteobacteria

    OpenAIRE

    Yannick Fleury; Patrick Le Chevalier; Benjamin Brillet; Eric Balnois; Camille Jégou; Florie Desriac

    2013-01-01

    After years of inadequate use and the emergence of multidrug resistant (MDR) strains, the efficiency of “classical” antibiotics has decreased significantly. New drugs to fight MDR strains are urgently needed. Bacteria hold much promise as a source of unusual bioactive metabolites. However, the potential of marine bacteria, except for Actinomycetes and Cyanobacteria, has been largely underexplored. In the past two decades, the structures of several antimicrobial compounds have been elucidated ...

  14. Collagen-like antimicrobial peptides.

    Science.gov (United States)

    Masuda, Ryo; Kudo, Masakazu; Dazai, Yui; Mima, Takehiko; Koide, Takaki

    2016-11-01

    Combinatorial library composed of rigid rod-like peptides with a triple-helical scaffold was constructed. The component peptides were designed to have various combinations of basic and neutral (or hydrophobic) amino acid residues based on collagen-like (Gly-Pro-Yaa)-repeating sequences, inspired from the basic and amphiphilic nature of naturally occurring antimicrobial peptides. Screening of the peptide pools resulted in identification of antimicrobial peptides. A structure-activity relationship study revealed that the position of Arg-cluster at N-terminus and cystine knots at C-terminus in the triple helix significantly contributed to the antimicrobial activity. The most potent peptide RO-A showed activity against Gram-negative Escherichia coli and Gram-positive Bacillus subtilis. In addition, Escherichia coli exposed to RO-A resulted in abnormal elongation of the cells. RO-A was also shown to have remarkable stability in human serum and low cytotoxicity to mammalian cells. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 453-459, 2016. PMID:27271210

  15. ANTIMICROBIAL RESISTANCE PATTERN OF STAPHYLOCOCCUS AUREUS ISOLATES FROM DAKSHINA KANNADA

    Directory of Open Access Journals (Sweden)

    Rao Venkatakrishna

    2011-03-01

    Full Text Available Methicillin resistant Staphylococcus aureus (MRSA is an important cause of infections in hospitals and pose a great challenge to the treating clinicians; even emergence of vancomycin resistance has been reported. Therefore the knowledge of prevalence of MRSA and their antimicrobial profile becomes necessary. This study is aimed to determine prevalence of MRSA and their antimicrobial sensitivity pattern in Dakshina Kannada.Clinical specimens and carrier samples were cultured as per standard methods. The isolates were identified by using catalase test, coagulase tube test, mannitol fermentation and DNAase test. Antimicrobial susceptibility test was done for the isolates as per Kirby-Bauer disc diffusion method; the isolates were also tested for methicillin resistance using oxacillin and cefoxitin discs.A total of 250 isolates were tested (200 clinical isolates and 50 from carriers and 67 MRSA isolates were obtained (52 clinical samples and 15 from carriers. The degree of resistance to penicillin, ampicillin, ciprofloxacin, clindamycin and erythromycin were 100%, 100%, 53-56%, 14-16 % and 45-48% respectively. Resistance to vancomycin was not found. As the degree of resistance of MRSA towards antibiotics varies from region to region, in vitro susceptibility testing of every isolate of MRSA in clinical laboratories is inevitable.

  16. Antimicrobial defence and persistent infection in insects revisited.

    Science.gov (United States)

    Makarova, Olga; Rodriguez-Rojas, Alex; Eravci, Murat; Weise, Chris; Dobson, Adam; Johnston, Paul; Rolff, Jens

    2016-05-26

    Insects show long-lasting antimicrobial immune responses that follow the initial fast-acting cellular processes. These immune responses are discussed to provide a form of phrophylaxis and/or to serve as a safety measure against persisting infections. The duration and components of such long-lasting responses have rarely been studied in detail, a necessary prerequisite to understand their adaptive value. Here, we present a 21 day proteomic time course of the mealworm beetle Tenebrio molitor immune-challenged with heat-killed Staphylococcus aureus The most upregulated peptides are antimicrobial peptides (AMPs), many of which are still highly abundant 21 days after infection. The identified AMPs included toll and imd-mediated AMPs, a significant number of which have no known function against S. aureus or other Gram-positive bacteria. The proteome reflects the selective arena for bacterial infections. The results also corroborate the notion of synergistic interactions in vivo that are difficult to model in vitroThis article is part of the themed issue 'Evolutionary ecology of arthropod antimicrobial peptides'. PMID:27160598

  17. Antimicrobial resistance among nosocomial isolates in a teaching hospital in Goa

    Directory of Open Access Journals (Sweden)

    Kamat U

    2008-01-01

    Full Text Available Background: Emergence of polyantimicrobial resistant strains of hospital pathogens has presented a challenge in the provision of good quality in-patient care. Inappropriate use of antibiotics in the hospital is largely responsible for this catastrophe. Bacteriological surveillance of the cases of nosocomial infections is crucial for framing an evidence-based antimicrobial policy for a hospital. Materials and Methods: A prospective study was undertaken among 498 patients from medicine and surgery wards in a tertiary teaching hospital in Goa. The patients were followed up clinico-bacteriologically for the occurrence of nosocomial infections (NI. Antibiotic susceptibility testing was done using Kirby-Bauer disc diffusion method. Results: The overall infection rate was 33.93 ± 4.16 infections per 100 patients. Urinary tract infection was the most common NI (26.63%, followed by surgical site infection (23.67%, wound infection (23% and nosocomial pneumonia (18.34%. Ninety-seven percent of the isolates were bacterial, while the others were fungal. More than 80% of the NIs were caused by Gram-negative bacteria, predominantly Pseudomonas aeruginosa, Escherichia coli and Aceinetobacter baumanii . Almost 70% of the isolates were resistant to all the antibiotics for which susceptibility was tested; the rest were sensitive to amikacin, cefoperazone-sulbactam and other antibiotics including methicillin, co-trimoxazole, teicoplenin, vancomycin and rifampicin, either singly or in combination. The proportion of MRSA was 71.4%. Resistance to a particular antibiotic was found to be directly proportional to the antibiotic usage in the study setting. Conclusion: Surveillance of nosocomial infections with emphasis on the microbiologic surveillance and frequent antimicrobial audit are critical towards curbing the evil of polyantimicrobial resistant nosocomial infections in a hospital.

  18. Antimicrobial activity of Argemone ochroleuca Sweet (Chicalote)

    OpenAIRE

    Francisco Daniel REYES; Celia Jimena PEÑA; Canales, Margarita; Jiménez, Manuel; Samuel MERÁZ; Tzasna HERNANDEZ

    2011-01-01

    Argemone ochroleuca Sweet (Papaveraceae) is used to treat eye infection, respiratory and dermatological disorders in Tepotzotlán, State of México (México). The aim of this work was to investigate antimicrobial activity of hexane, ethyl acetate and methanol extracts from aerial parts of A. ochroleuca. The antimicrobial activity was evaluated against thirteen bacteria and nine fungal strains. Only methanol extract showed antimicrobial activity. S. aureus (MIC= 125 ¿g/mL) and C. neoformans (MIC=...

  19. Antimicrobial resistance in Libya: 1970-2011

    OpenAIRE

    Ghenghesh, Khalifa Sifaw; Rahouma, Amal; Tawil, Khaled; Zorgani, Abdulaziz; Franka, Ezzedin

    2013-01-01

    Resistance to antimicrobial agents is a major health problem that affects the whole world. Providing information on the past state of antimicrobial resistance in Libya may assist the health authorities in addressing the problem more effectively in the future. Information was obtained mainly from Highwire Press (including PubMed) search for the period 1970-2011 using the terms ‘antibiotic resistance in Libya’, ‘antimicrobial resistance in Libya’, ‘tuberculosis in Libya’, and ‘primary and acqui...

  20. Antimicrobial peptides in human skin disease

    OpenAIRE

    Kenshi, Yamasaki; Richard, L. Gallo

    2007-01-01

    The skin continuously encounters microbial pathogens. To defend against this, cells of the epidermis and dermis have evolved several innate strategies to prevent infection. Antimicrobial peptides are one of the primary mechanisms used by the skin in the early stages of immune defense. In general, antimicrobial peptides have broad antibacterial activity against gram-positive and negative bacteria and also show antifungal and antiviral activity. The antimicrobial activity of most peptides occur...

  1. Nanoparticle-Based Antimicrobials: Surface Functionality is Critical

    Science.gov (United States)

    Gupta, Akash; Landis, Ryan F.; Rotello, Vincent M.

    2016-01-01

    Bacterial infections cause 300 million cases of severe illness each year worldwide. Rapidly accelerating drug resistance further exacerbates this threat to human health. While dispersed (planktonic) bacteria represent a therapeutic challenge, bacterial biofilms present major hurdles for both diagnosis and treatment. Nanoparticles have emerged recently as tools for fighting drug-resistant planktonic bacteria and biofilms. In this review, we present the use of nanoparticles as active antimicrobial agents and drug delivery vehicles for antibacterial therapeutics. We further focus on how surface functionality of nanomaterials can be used to target both planktonic bacteria and biofilms. PMID:27006760

  2. Cooperative development of antimicrobials: looking back to look ahead.

    Science.gov (United States)

    Nathan, Carl

    2015-10-01

    As foundations and governments mobilize to tackle antimicrobial resistance (AMR), several experiments in academic-industrial collaboration have emerged. Here, I examine two historical precedents, the Penicillin Project and the Malaria Project of the Second World War, and two contemporary examples, the Tuberculosis Drug Accelerator programme and the Tres Cantos Open Lab. These and related experiments suggest that different strategies can be effective in managing academic-industrial collaborations, and that such joint projects can prosper in both multisite and single-site forms, depending on the specific challenges and goals of each project. The success of these strategies and the crisis of AMR warrant additional investment in similar projects. PMID:26373373

  3. Carbon nanodots as molecular scaffolds for development of antimicrobial agents.

    Science.gov (United States)

    Ngu-Schwemlein, Maria; Chin, Suk Fun; Hileman, Ryan; Drozdowski, Chris; Upchurch, Clint; Hargrove, April

    2016-04-01

    We report the potential of carbon nanodots (CNDs) as a molecular scaffold for enhancing the antimicrobial activities of small dendritic poly(amidoamines) (PAMAM). Carbon nanodots prepared from sago starch are readily functionalized with PAMAM by using N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS). Electron microscopy images of these polyaminated CNDs show that they are approximately 30-60nm in diameter. Infrared and fluorescence spectroscopy analyses of the water-soluble material established the presence of the polyamidoaminated moiety and the intrinsic fluorescence of the nanodots. The polyaminated nanodots (CND-PAM1 and CND-PAM2) exhibit in vitro antimicrobial properties, not only to non-multidrug resistant bacteria but also to the corresponding Gram-negative multidrug bacteria. Their minimum inhibitory concentration (MIC) ranges from 8 to 64μg/mL, which is much lower than that of PAMAM G1 or the non-active PAMAM G0 and CNDs. Additionally, they show synergistic effect in combination with tetracycline or colistin. These preliminary results imply that CNDs can serve as a promising scaffold for facilitating the rational design of antimicrobial materials for combating the ever-increasing threat of antibiotic resistance. Moreover, their fluorescence could be pertinent to unraveling their mode of action for imaging or diagnostic applications. PMID:26923697

  4. Synthesis of New Macrocyclic Polyamides as Antimicrobial Agent Candidates

    Directory of Open Access Journals (Sweden)

    Osama I. Abd El-Salam

    2012-12-01

    Full Text Available A series of macrocyclic imides and Schiff-bases have been prepared via the cyclocondensation of pyridine-2,6-dicarbonyl dichloride (1 with L-ornithine methyl ester to give the corresponding macrocyclic bisester 2. Treatment of 2 with hydrazine hydrate gave macrocyclic bisacid hydrazide 3, which was used as starting material. Condensation of bishydrazide 3 with diacid anhydrides or aromatic aldehydes in refluxing acetic acid or ethanol gave the corresponding macrocyclic bisimides 4, 5a,b and macrocyclic bis- hydrazones 6a–j, respectively. The structure assignments of the new compounds were based on chemical and spectroscopic evidence. The antimicrobial screening showed that many of these newly synthesized compounds have good antimicrobial activities, comparable to ampicillin and ketaconazole used as reference drugs.

  5. Ultrafast Killing and Self-Gelling Antimicrobial Imidazolium Oligomers.

    Science.gov (United States)

    Riduan, Siti Nurhanna; Yuan, Yuan; Zhou, Feng; Leong, Jiayu; Su, Haibin; Zhang, Yugen

    2016-04-01

    Infectious diseases and the increasing threat of worldwide pandemics have underscored the importance of antibiotics and hygiene. Intensive efforts have been devoted to developing new antibiotics to meet the rapidly growing demand. In particular, advancing the knowledge of the structure-property-activity relationship is critical to expedite the design and development of novel antimicrobial with the needed potential and efficacy. Herein, a series of new antimicrobial imidazolium oligomers are developed with the rational manipulation of terminal group's hydrophobicity. These materials exhibit superior activity, excellent selectivity, ultrafast killing (>99.7% killing within 30 s), and desirable self-gelling properties. Molecular dynamic simulations reveal the delicate effect of structural changes on the translocation motion across the microbial cell membrane. The energy barrier of the translocation process analyzed by free energy calculations provides clear kinetic information to suggest that the spontaneous penetration requires a very short timescale of seconds to minutes for the new imidazolium oligomers. PMID:26891016

  6. Driving engineering of novel antimicrobial peptides from simulations of peptide-micelle interactions

    DEFF Research Database (Denmark)

    Khandelia, Himanshu; Langham, Allison A; Kaznessis, Yiannis N

    2006-01-01

    Simulations of antimicrobial peptides in membrane mimics can provide the high resolution, atomistic picture that is necessary to decipher which sequence and structure components are responsible for activity and toxicity. With such detailed insight, engineering new sequences that are active but non...... peptides and their interaction with membrane mimics. In this article, we discuss the promise and the challenges of widely used models and detail our recent work on peptide-micelle simulations as an attractive alternative to peptide-bilayer simulations. We detail our results with two large structural...... classes of peptides, helical and beta-sheet and demonstrate how simulations can assist in engineering of novel antimicrobials with therapeutic potential....

  7. Antimicrobial resistance among Brazilian Corynebacterium diphtheriae strains

    Directory of Open Access Journals (Sweden)

    Gabriela Andrade Pereira

    2008-08-01

    Full Text Available The increasing problems with multidrug resistance in relation to Corynebacterium, including C. diphtheriae, are examples of challenges confronting many countries. For this reason, Brazilian C. diphtheriae strains were evaluated by the E-Test for their susceptibility to nine antibacterial drugs used in therapy. Resistance (MIC < 0.002; 0.38 µg/ml to penicillin G was found in 14.8% of the strains tested. Although erythromycin (MIC90 0.75 µg/ml and azithromycin (MIC90 0.064 µg/ml were active against C. diphtheriae in this study, 4.2% of the strains showed decreased susceptibility (MIC 1.0 µg/ml to erythromycin. Multiple resistance profiles were determined by the disk diffusion method using 31 antibiotics. Most C. diphtheriae strains (95.74% showed resistance to mupirocin, aztreonam, ceftazidime, and/or oxacillin, ampicillin, penicillin, tetracycline, clindamycin, lincomycin, and erythromycin. This study presents the antimicrobial susceptibility profiles of Brazilian C. diphtheriae isolates. The data are of value to practitioners, and suggest that some concern exists regarding the use of penicillin.

  8. Impregnation of silver sulfadiazine into bacterial cellulose for antimicrobial and biocompatible wound dressing

    International Nuclear Information System (INIS)

    Silver sulfadiazine (SSD) is a useful antimicrobial agent for wound treatment. However, recent findings indicate that conventional SSD cream has several drawbacks for use in treatments. Bacterial cellulose (BC) is a promising material for wound dressing due to its outstanding properties of holding water, strength and degradability. Unfortunately, BC itself exhibits no antimicrobial activity. A combination of SSD and BC is envisaged to form a new class of wound dressing with both antimicrobial activity and biocompatibility, which has not been reported to date. To achieve antimicrobial activity, SSD particles were impregnated into BC by immersing BC into SSD suspension after ultrasonication, namely SSD–BC. Parameters influencing SSD–BC impregnation were systematically studied. Optimized conditions of sonication time for no less than 90 min and the proper pH value between 6.6 and 9.0 were suggested. The absorption of SSD onto the BC nanofibrous network was revealed by XRD and SEM analyses. The SSD–BC membranes exhibited significant antimicrobial activities against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus evaluated by the disc diffusion method. In addition, the favorable biocompatibility of SSD–BC was verified by MTT colorimetry, epidermal cell counting method and optical microscopy. The results demonstrate the potential of SSD–BC membranes as a new class of antimicrobial and biocompatible wound dressing. (paper)

  9. Antimicrobial use in swine production and its effect on the swine gut microbiota and antimicrobial resistance.

    Science.gov (United States)

    Holman, Devin B; Chénier, Martin R

    2015-11-01

    Antimicrobials have been used in swine production at subtherapeutic levels since the early 1950s to increase feed efficiency and promote growth. In North America, a number of antimicrobials are available for use in swine. However, the continuous administration of subtherapeutic, low concentrations of antimicrobials to pigs also provides selective pressure for antimicrobial-resistant bacteria and resistance determinants. For this reason, subtherapeutic antimicrobial use in livestock remains a source of controversy and concern. The swine gut microbiota demonstrates a number of changes in response to antimicrobial administration depending on the dosage, duration of treatment, age of the pigs, and gut location that is sampled. Both culture-independent and -dependent studies have also shown that the swine gut microbiota contains a large number of antimicrobial resistance determinants even in the absence of antimicrobial exposure. Heavy metals, such as zinc and copper, which are often added at relatively high doses to swine feed, may also play a role in maintaining antimicrobial resistance and in the stability of the swine gut microbiota. This review focuses on the use of antimicrobials in swine production, with an emphasis on the North American regulatory context, and their effect on the swine gut microbiota and on antimicrobial resistance determinants in the gut microbiota. PMID:26414105

  10. Activity of Antimicrobial Silver Polystyrene Nanocomposites

    Directory of Open Access Journals (Sweden)

    M. Palomba

    2012-01-01

    Full Text Available A simple technique based on doping polymers with in situ generated silver nanoparticles (Ag/PS films has been developed. In particular, an antiseptic material has been prepared by dissolving silver 1,5-cyclooctadiene-hexafluoroacetylacetonate in amorphous polystyrene, and the obtained solid solution has been heated for ca. 10 s at a convenient temperature (180°C. Under such conditions the metal precursor decomposes producing silver atoms that diffuse into the polymer and clusterize. The antimicrobial characteristics of the resulting polystyrene-based material have been accurately evaluated toward Escherichia coli (E. coli comparing the cytotoxicity effect of 10 wt.% and 30 wt.% (drastic and mild annealing silver-doped polystyrene to the corresponding pure micrometric silver powder. Two different bacterial viability assays were performed in order to demonstrate the cytotoxic effect of Ag/PS films on cultured E. coli: (1 turbidimetric determination of optical density; (2 BacLight fluorescence-based test. Both methods have shown that silver-doped polystyrene (30 wt.% provides higher antibacterial activity than pure Ag powder, under similar concentration and incubation conditions.

  11. From antimicrobial to anticancer peptides. A review.

    Directory of Open Access Journals (Sweden)

    Diana eGaspar

    2013-10-01

    Full Text Available Antimicrobial peptides (AMPs are part of the innate immune defense mechanism of many organisms. Although AMPs have been essentially studied and developed as potential alternatives for fighting infectious diseases, their use as anticancer peptides (ACPs in cancer therapy either alone or in combination with other conventional drugs has been regarded as a therapeutic strategy to explore. As human cancer remains a cause of high morbidity and mortality worldwide, an urgent need of new, selective and more efficient drugs is evident. Even though ACPs are expected to be selective towards tumor cells without impairing the normal body physiological functions, the development of a selective ACP has been a challenge. It is not yet possible to predict antitumor activity based on ACPs structures. ACPs are unique molecules when compared to the actual chemotherapeutic arsenal available for cancer treatment and display a variety of modes of action which in some types of cancer seem to co-exist. Regardless the debate surrounding the definition of structure-activity relationships for ACPs, great effort has been invested in ACP design and the challenge of improving effective killing of tumor cells remains. As detailed studies on ACPs mechanisms of action are crucial for optimizing drug development, in this review we provide an overview of the literature concerning peptides’ structure, modes of action, selectivity and efficacy and also summarize some of the many ACPs studied and/or developed for targeting different solid and hematologic malignancies with special emphasis on the first group. Strategies described for drug development and for increasing peptide selectivity towards specific cells while reducing toxicity are also discussed.

  12. Featherweight Challenge

    Science.gov (United States)

    Love, Tyler S.; Ryan, Larry

    2012-01-01

    As science, technology education, and engineering programs suffer budget cuts, educators continue to seek cost-effective activities that engage students and reinforce standards. The featherweight challenge is a hands-on activity that challenges students to continually refine their design while not breaking the budget. This activity uses one of the…

  13. Cationic Antimicrobial Polymers and Their Assemblies

    Directory of Open Access Journals (Sweden)

    Ana Maria Carmona-Ribeiro

    2013-05-01

    Full Text Available Cationic compounds are promising candidates for development of antimicrobial agents. Positive charges attached to surfaces, particles, polymers, peptides or bilayers have been used as antimicrobial agents by themselves or in sophisticated formulations. The main positively charged moieties in these natural or synthetic structures are quaternary ammonium groups, resulting in quaternary ammonium compounds (QACs. The advantage of amphiphilic cationic polymers when compared to small amphiphilic molecules is their enhanced microbicidal activity. Besides, many of these polymeric structures also show low toxicity to human cells; a major requirement for biomedical applications. Determination of the specific elements in polymers, which affect their antimicrobial activity, has been previously difficult due to broad molecular weight distributions and random sequences characteristic of radical polymerization. With the advances in polymerization control, selection of well defined polymers and structures are allowing greater insight into their structure-antimicrobial activity relationship. On the other hand, antimicrobial polymers grafted or self-assembled to inert or non inert vehicles can yield hybrid antimicrobial nanostructures or films, which can act as antimicrobials by themselves or deliver bioactive molecules for a variety of applications, such as wound dressing, photodynamic antimicrobial therapy, food packing and preservation and antifouling applications.

  14. Next-Generation Antimicrobial Susceptibility Testing

    OpenAIRE

    Belkum, Alex van; Dunne, W. Michael

    2013-01-01

    Antimicrobial resistance has emerged as one of the most-significant health care problems of the new millennium, and the clinical microbiology laboratory plays a central role in optimizing the therapeutic management of patients with infection. This minireview explores the potential value of innovative methods for antimicrobial susceptibility testing of microorganisms that could provide valuable alternatives to existing methodologies in the very near future.

  15. Synthesis and antimicrobial activity of squalamine analogue.

    Science.gov (United States)

    Kim, H S; Choi, B S; Kwon, K C; Lee, S O; Kwak, H J; Lee, C H

    2000-08-01

    Synthesis and antimicrobial activity of squalamine analogue 2 are reported. The synthesis of 2 was accomplished from bisnoralcohol 3. The spermidine moiety was introduced via reductive amination of an appropriately functionalized 3beta-aminosterol with spermidinyl aldehyde 17 utilizing sodium triacetoxyborohydride as the reducing agent. Compound 2 shows weaker antimicrobial activity than squalamine. PMID:11003150

  16. Antimicrobial activity of Ethiopian medicinal plants

    OpenAIRE

    Bernášková, Eva

    2013-01-01

    In vitro antimicrobial activity of eighteen Ethiopian medicinal plant species that were selected based on ethnobotanical information on their traditional use to treat infectious diseases was determined by the broth microdilution method. The antimicrobial activity of ethanol extracts of selected plants against potentially pathogenic microorganism such as Bacillus cereus, Bacteroides fragilis, Candida albicans, Clostridium perfringens, Enterococcus faecalis, Escherichia coli, Listeria monocytog...

  17. Sixty years of antimicrobial use in animals

    DEFF Research Database (Denmark)

    Guardabassi, Luca

    2013-01-01

    This, the last in our series of feature articles celebrating 125 years of Veterinary Record, aims to provide an overview of antimicrobial use in animals. Starting with a journey through the history of antimicrobial use in animals, Luca Guardabassi gives his opinion on the current zoonotic risks...

  18. International cooperation to improve access to and sustain effectiveness of antimicrobials.

    Science.gov (United States)

    Årdal, Christine; Outterson, Kevin; Hoffman, Steven J; Ghafur, Abdul; Sharland, Mike; Ranganathan, Nisha; Smith, Richard; Zorzet, Anna; Cohn, Jennifer; Pittet, Didier; Daulaire, Nils; Morel, Chantal; Rizvi, Zain; Balasegaram, Manica; Dar, Osman A; Heymann, David L; Holmes, Alison H; Moore, Luke S P; Laxminarayan, Ramanan; Mendelson, Marc; Røttingen, John-Arne

    2016-01-16

    Securing access to effective antimicrobials is one of the greatest challenges today. Until now, efforts to address this issue have been isolated and uncoordinated, with little focus on sustainable and international solutions. Global collective action is necessary to improve access to life-saving antimicrobials, conserving them, and ensuring continued innovation. Access, conservation, and innovation are beneficial when achieved independently, but much more effective and sustainable if implemented in concert within and across countries. WHO alone will not be able to drive these actions. It will require a multisector response (including the health, agriculture, and veterinary sectors), global coordination, and financing mechanisms with sufficient mandates, authority, resources, and power. Fortunately, securing access to effective antimicrobials has finally gained a place on the global political agenda, and we call on policy makers to develop, endorse, and finance new global institutional arrangements that can ensure robust implementation and bold collective action. PMID:26603920

  19. Purification Technology and Antimicrobial Activity Analysis of Antimicrobial Peptide from Ovotransferrin

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tie-hua; ZHENG Jian; YE Hai-qing; YU Ya-li; ZHAO Ping; LIU Jing-bo

    2011-01-01

    Antibacterial peptides mixture purified from Ovotransferrin by pepsin digest was used as the raw material.Peptide sections with good antibacterial activity were determined after bacteriostasis experiments, its molecular weight and amino acid composition were analyzed. The results of experiments indicate that with Sephadex G-50 and distilled water as mobile phase, detection wavelength 220 nm, flow rate 1.5 mL/min, sample density 0.2 g/mL, and volume 0.2 mL are the optimal conditions. Bacteriostasis experiments of the fraction of purified peaks were carried out and the result was: peak 1>peak 3>peak 2; the molecular weight of peak 1 was about 3015 by high performance liquid chromatography; active peptide possessed positive charges by amino acid analysis, its cationic characteristics are in accordance with the nature of antimicrobial peptides.

  20. Antimicrobial resistance and genetic characterization of fluoroquinolone resistance of Pseudomonas aeruginosa isolated from canine infections.

    Science.gov (United States)

    Rubin, J; Walker, R D; Blickenstaff, K; Bodeis-Jones, S; Zhao, S

    2008-09-18

    Infections with antimicrobial-resistant bacteria are a great challenge in both human and veterinary medicine. The purpose of this study was to determine antimicrobial susceptibility of 106 strains of Pseudomonas aeruginosa isolated from dogs with otitis and pyoderma from 2003 to 2006 in the United States. Three antimicrobial panels, including 6 classes and 32 antimicrobial agents, were used. A wide range of susceptibility patterns were noted with some isolates being resistant to between 8 and 28 (mean 16) of the antimicrobials tested. Among the beta-lactams, all isolates were resistant to ampicillin, cefoxitin, cefpodoxime, cephalothin and cefazolin followed by amoxicillin/clavulanic acid (99%), ceftiofur (97%), ceftriaxone (39%), cefotaxime (26%), and cefotaxime/clavulanic acid (20%), whereas less than 7% of isolates were resistant to ceftazidime/clavulanic acid, ceftazidime, piperacillin/tazobactam or cefepime. Two isolates were resistant to the carbapenems. Among the quinolones and fluoroquinolones, the most isolates were resistant to naladixic acid (96%), followed by orbifloxacin (52%), difloxacin (43%), enrofloxacin (31%), marbofloxacin (27%), gatifloxacin (23%), levofloxacin (21%), and ciprofloxacin (16%). Among the aminoglycosides, the most resistance was seen to kanamycin (90%), followed by streptomycin (69%), gentamicin (7%), and amikacin (3%). Of the remaining antimicrobials 100% of the isolates were resistant to chloramphenicol followed by tetracycline (98%), trimethoprim/sulfamethoxazole (57%), and sulfisoxazole (51%). Point mutations were present in gyrA, gyrB, parC, and/or parE genes among 34 of the 102 naladixic acid-resistant isolates. Two isolates contained class 1 integrons carrying aadA gene conferring streptomycin and spectinomycin resistance. The findings suggest that many antimicrobial agents commonly used in companion animals may not constitute appropriate therapy for canine pseudomonas infections. PMID:18395369

  1. Development of antimicrobial optimum glass ionomer; Desenvolvimento de ionomero de vidro antimicrobiano otimo

    Energy Technology Data Exchange (ETDEWEB)

    Angioletto, E.; Tezza, V.B.; Santos, M.J.; Montedo, O.R.K.; Pich, C.T.; Fiori, M.A. [Universidade do Extremo Sul Catarinense (UNESC), Criciuma, SC (Brazil); Angioletto, Ev. [Biorosam Biotecnologia Ltda., SC (Brazil)

    2010-07-01

    The use of glass ionomer for restorations in dentistry for lower income population is a well established practice in public clinics of Brazil. However the average price of this kind of material and its low durability still have a negative impact on public health for being imported and frequently replaced it becomes expensive for the manufacturers and for public agencies. In glass ionomer the main antimicrobial agent is fluoride, which is released gradually. The material used for filling provides an average life of five years and its durability can be increased if the ionomer contains other oligodynamic elements. It was formulated, merged a new optimized glass ionomer which was characterized by X-ray diffraction, ion measurement and antimicrobial activity. This new product showed promising results, that pointed structural stability an increase of antimicrobial efficiency. (author)

  2. Effect of Graphene Nanoplatelets on the Physical and Antimicrobial Properties of Biopolymer-Based Nanocomposites

    Directory of Open Access Journals (Sweden)

    Roberto Scaffaro

    2016-05-01

    Full Text Available In this work, biopolymer-based nanocomposites with antimicrobial properties were prepared via melt-compounding. In particular, graphene nanoplatelets (GnPs as fillers and an antibiotic, i.e., ciprofloxacin (CFX, as biocide were incorporated in a commercial biodegradable polymer blend of poly(lactic acid (PLA and a copolyester (BioFlex®. The prepared materials were characterized by scanning electron microscopy (SEM, and rheological and mechanical measurements. Moreover, the effect of GnPs on the antimicrobial properties and release kinetics of CFX was evaluated. The results indicated that the incorporation of GnPs increased the stiffness of the biopolymeric matrix and allowed for the tuning of the release of CFX without hindering the antimicrobial activity of the obtained materials.

  3. Comparative performance of a panel of commercially available antimicrobial nanocoatings in Europe

    Science.gov (United States)

    Molling, Johan W; Seezink, Jacques W; Teunissen, Birgit EJ; Muijrers-Chen, Inhua; Borm, Paul JA

    2014-01-01

    Background Bacterial resistance against the classic antibiotics is posing an increasing challenge for the prevention and treatment of infections in health care environments. The introduction of antimicrobial nanocoatings with active ingredients provides alternative measures for active killing of microorganisms, through a preventive hygiene approach. Purpose The purpose of this study was to investigate the antimicrobial activity of a panel of antimicrobial coatings available on the European market. Methods A comparative, biased selection of commercially available antimicrobial coatings was tested for antimicrobial efficiency. Suppliers were contacted to deliver their coatings on glass and/or stainless steel substrates. In total, 23 coatings from eleven suppliers were received, which were investigated for their effect on the growth of Escherichia coli, using the International Organization for Standardization (ISO) 22196 protocol. Results The majority of nanomaterial-containing coatings (n=13) contained nanosilver (n=12), while only one had photocatalytic TiO2 as the active particle. The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2. Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6) was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix. Besides these two compounds, coatings containing TiO2, poly(dimethylsiloxane), triclosan, or zinc pyrithione evoked 100% killing of E. coli. Conclusion Our findings indicate that nanosilver dominates the nanoparticle-based coatings and performs adequately. However, considering the unknowns in relation to ecotoxicological emission and effects, it needs further consideration before widespread application into different

  4. Comparative performance of a panel of commercially available antimicrobial nanocoatings in Europe

    Directory of Open Access Journals (Sweden)

    Molling JW

    2014-11-01

    Full Text Available Johan W Molling, Jacques W Seezink, Birgit EJ Teunissen, Inhua Muijrers-Chen, Paul JA Borm Zuyd University of Applied Sciences, Heerlen, the Netherlands Background: Bacterial resistance against the classic antibiotics is posing an increasing challenge for the prevention and treatment of infections in health care environments. The introduction of antimicrobial nanocoatings with active ingredients provides alternative measures for active killing of microorganisms, through a preventive hygiene approach. Purpose: The purpose of this study was to investigate the antimicrobial activity of a panel of antimicrobial coatings available on the European market. Methods: A comparative, biased selection of commercially available antimicrobial coatings was tested for antimicrobial efficiency. Suppliers were contacted to deliver their coatings on glass and/or stainless steel substrates. In total, 23 coatings from eleven suppliers were received, which were investigated for their effect on the growth of Escherichia coli, using the International Organization for Standardization (ISO 22196 protocol. Results: The majority of nanomaterial-containing coatings (n=13 contained nanosilver (n=12, while only one had photocatalytic TiO2 as the active particle. The differences in antimicrobial activity among all of the coatings, expressed as log reduction values, varied between 1.3 and 6.6, while the variation within the nanomaterial-based group was between 2.0 and 6.2. Although nanosilver coatings were on average very effective in reducing the number of viable bacteria after challenge, the strongest log reduction (6.6 was seen with a coating that has immobilized, covalently bound quaternary ammonium salt in its matrix. Besides these two compounds, coatings containing TiO2, poly(dimethylsiloxane, triclosan, or zinc pyrithione evoked 100% killing of E. coli. Conclusion: Our findings indicate that nanosilver dominates the nanoparticle-based coatings and performs adequately

  5. Attitudes and Behaviours to Antimicrobial Prescribing following Introduction of a Smartphone App

    Science.gov (United States)

    Panesar, Preet; Jones, Alisdair; Aldous, Alicia; Kranzer, Katharina; Halpin, Eamus; Fifer, Helen; Macrae, Bruce; Curtis, Carmel

    2016-01-01

    Objectives Our hospital replaced the format for delivering portable antimicrobial prescribing guidance from a paper-based pocket guide to a smartphone application (app). We used this opportunity to assess the relationship between its use and the attitudes and behaviours of antimicrobial prescribers. Methods We used 2 structured cross-sectional questionnaires issued just prior to and 3 months following the launch of the smartphone app. Ordinal Likert scale responses to both frequencies of use and agreement statements permitted quantitative assessment of the relationship between variables. Results The smartphone app was used more frequently than the pocket guide it replaced (p < 0.01), and its increased use was associated with sentiments that the app was useful, easy to navigate and its content relevant. Users who used the app more frequently were more likely to agree that the app encouraged them to challenge inappropriate prescribing by their colleagues (p = 0.001) and were more aware of the importance of antimicrobial stewardship (p = 0.005). Reduced use of the app was associated with agreement that senior physicians’ preferences for antimicrobial prescribing would irrespectively overrule guideline recommendations (p = 0.0002). Conclusions Smartphone apps are an effective and acceptable format to deliver guidance on antimicrobial prescribing. Our findings suggest that they may empower users to challenge incorrect prescribing, breaking well-established behaviours, and thus supporting vital stewardship efforts in an era of increased antimicrobial resistance. Future work will need to focus on the direct impact on drug prescriptions as well as identifying barriers to implementing smartphone apps in other clinical settings. PMID:27111775

  6. Maillard reaction products as antimicrobial components for packaging films.

    Science.gov (United States)

    Hauser, Carolin; Müller, Ulla; Sauer, Tanja; Augner, Kerstin; Pischetsrieder, Monika

    2014-02-15

    Active packaging foils with incorporated antimicrobial agents release the active ingredient during food storage. Maillard reaction products (MRPs) show antimicrobial activity that is at least partially mediated by H2O2. De novo generation of H2O2 by an MRP fraction, extracted from a ribose/lysine Maillard reaction mixture by 85% ethanol, was monitored at three concentrations (1.6, 16.1, and 32.3g/L) and three temperatures (4, 25, and 37 °C) between 0 and 96 h, reaching a maximum of 335 μM H2O2 (32.3g/L, 37 °C, 96 h). The active MRP fraction (16.1g/L) completely inhibited the growth of Escherichia coli for 24h and was therefore incorporated in a polyvinyl acetate-based lacquer and dispersed onto a low-density polyethylene film. The coated film generated about 100 μM H2O2 and resulted in a log-reduction of >5 log-cycles against E. coli. Thus, MRPs can be considered as active ingredients for antimicrobial packaging materials. PMID:24128521

  7. Essential oils as natural food antimicrobial agents: a review.

    Science.gov (United States)

    Vergis, Jess; Gokulakrishnan, P; Agarwal, R K; Kumar, Ashok

    2015-01-01

    Food-borne illnesses pose a real scourge in the present scenario as the consumerism of packaged food has increased to a great extend. Pathogens entering the packaged foods may survive longer, which needs a check. Antimicrobial agents either alone or in combination are added to the food or packaging materials for this purpose. Exploiting the antimicrobial property, essential oils are considered as a "natural" remedy to this problem other than its flavoring property instead of using synthetic agents. The essential oils are well known for its antibacterial, antiviral, antimycotic, antiparasitic, and antioxidant properties due to the presence of phenolic functional group. Gram-positive organisms are found more susceptible to the action of the essential oils. Essential oils improve the shelf-life of packaged products, control the microbial growth, and unriddle the consumer concerns regarding the use of chemical preservatives. This review is intended to provide an overview of the essential oils and their role as natural antimicrobial agents in the food industry. PMID:24915323

  8. Antimicrobial Peptides: Versatile Biological Properties

    Directory of Open Access Journals (Sweden)

    Muthuirulan Pushpanathan

    2013-01-01

    Full Text Available Antimicrobial peptides are diverse group of biologically active molecules with multidimensional properties. In recent past, a wide variety of AMPs with diverse structures have been reported from different sources such as plants, animals, mammals, and microorganisms. The presence of unusual amino acids and structural motifs in AMPs confers unique structural properties to the peptide that attribute for their specific mode of action. The ability of these active AMPs to act as multifunctional effector molecules such as signalling molecule, immune modulators, mitogen, antitumor, and contraceptive agent makes it an interesting candidate to study every aspect of their structural and biological properties for prophylactic and therapeutic applications. In addition, easy cloning and recombinant expression of AMPs in heterologous plant host systems provided a pipeline for production of disease resistant transgenic plants. Besides these properties, AMPs were also used as drug delivery vectors to deliver cell impermeable drugs to cell interior. The present review focuses on the diversity and broad spectrum antimicrobial activity of AMPs along with its multidimensional properties that could be exploited for the application of these bioactive peptides as a potential and promising drug candidate in pharmaceutical industries.

  9. Antimicrobial outcomes in plasma medicine

    Science.gov (United States)

    Ryan, Thomas P.; Stalder, Kenneth R.; Woloszko, Jean

    2015-03-01

    Plasma is referred to as the fourth state of matter and is frequently generated in the environment of a strong electric field. The result consists of highly reactive species--ions, electrons, reactive atoms and molecules, and UV radiation. Plasma Medicine unites a number of fields, including Physics, Plasma Chemistry, Cell Biology, Biochemistry, and Medicine. The treatment modality utilizes Cold Atmospheric Plasma (CAP), which is able to sterilize and treat microbes in a nonthermal manner. These gas-based plasma systems operate at close to room temperature and atmospheric pressure, making them very practical for a range of potential treatments and are highly portable for clinical use throughout the health care system. The hypothesis is that gas based plasma kills bacteria, fungus, and viruses but spares mammalian cells. This paper will review systematic work which shows examples of systems and performance in regards to antimicrobial effects and the sparing of mammalian cells. The mechanism of action will be discussed, as well as dosing for the treatment of microbial targets, including sterilization processes, another important healthcare need. In addition, commercial systems will be overviewed and compared, along with evidence-based, patient results. The range of treatments cover wound treatment and biofilms, as well as antimicrobial treatment, with little chance for resistance and tolerance, as in drug regimens. Current clinical studies include applications in dentistry, food treatment, cancer treatment, wound treatment for bacteria and biofilms, and systems to combat health care related infections.

  10. Determining Chemical Composition and Antimicrobial Activity of Feverfew (Tanacetum parthenium L.) Essential Oil on Some Microbial Strains

    OpenAIRE

    Zahra Izadi; Majid Aghaalikhani; Mahmood Esna-Ashari; Poorandokht Davoodi

    2013-01-01

    Background: Feverfew (Tanacetum parthenium L.) is a herbal plant that has anti- septic, anti-microbial, anti-parasitic and anti-inflammatory effects. The main objective of this study is to evaluate the antimicrobial effect of shoot essential oil (essential oil of the aerial parts of the plant) of the feverfew on a number of microorganisms including gram-negative and gram-positive bacteria, filamentous fungi and yeasts. Materials and Methods: In this empirical study, plant samples were collect...

  11. Comparison of the antimicrobial effect of heavy silicone oil and conventional silicone oil against endophthalmitis-causing agents

    OpenAIRE

    Nurgül Örnek; Teoman Apan; Reyhan Oğurel; Kemal Örnek

    2014-01-01

    Purpose: To conduct an in vitro experimental study comparing the effectiveness of conventional silicone oil and heavy silicone oil against endophthalmitis-causing agents. Materials and Methods: The antimicrobial activity of conventional silicone oil (RS OIL 5000) and heavy silicone oil (heavySil 1500) was tested. The antimicrobial effects of both silicone oils were determined by the growing capability of the microorganism. Results: The number of Staphylococcus aureus, Staphylococcus epidermid...

  12. Chemical Composition and Antimicrobial Activity of Leaf, Ripe and Unripe Peel of Bitter Orange (Citrus aurantium) Essential Oils

    OpenAIRE

    Fatemeh Azhdarzadeh; Mohammad Hojjati

    2016-01-01

    Background and Objectives: The chemical composition and antimicrobial activity of bitter orange (Citrus aurantium) leaf, ripe and unripe peel essential oils, cultivated in southwest of Iran, were investigated. Materials and Methods: The analysis of chemical composition of hydro-distilled essential oils was carried out by GC-MS. The disc diffusion and broth micro-dilution were used to assay the antimicrobial effect of achieved essential oils. Results: According to the GC-MS analysis, 3...

  13. Antimicrobial activity of novel nanostructured Cu-SiO2 coatings prepared by chemical vapour deposition against hospital related pathogens

    OpenAIRE

    Varghese, Sajnu; ElFakhri, Souad O; Sheel, David W.; Sheel, Paul; Bolton, Frederick J Eric; Foster, Howard A

    2013-01-01

    There is increasing recognition that the healthcare environment acts as an important reservoir for transmission of healthcare acquired infections (HCAI). One method of reducing environmental contamination would be use of antimicrobial materials. The antimicrobial activity of thin silica-copper films prepared by chemical vapour deposition was evaluated against standard strains of bacteria used for disinfectant testing and bacteria of current interest in HCAI. The structure of the coatings was ...

  14. Nanoscale imaging and hydrophobicity mapping of the antimicrobial effect of copper on bacterial surfaces.

    Science.gov (United States)

    Wang, Congzhou; Ehrhardt, Christopher J; Yadavalli, Vamsi K

    2016-09-01

    Copper has a long historical role in the arena of materials with antimicrobial properties. Various forms of copper ranging from surfaces to impregnation in textiles and particles, have attracted considerable interest owing to their versatility, potency, chemical stability, and low cost. However, the effects and mechanisms of their antimicrobial action is still unclear. In this study, the effect of copper particles on Escherichia coli was studied at the nanoscale using atomic force microscopy (AFM). Time-lapse AFM images at the single cell level show the morphological changes on live E. coli during antimicrobial treatment, in which for the first time, this process was followed in situ on the same cell over time. AFM-based hydrophobicity mapping further showed that incubating cells with Cu decreased the surface hydrophobicity with an increase of incubation time. Specifically, we are able to visualize both morphology and physico-chemical nature of the bacterial cell surface change in response to copper treatment, leading to the membrane damage and cytoplasm leakage. Overall, the time-lapse AFM imaging combined with hydrophobicity mapping approach presented here provides spatio-temporal insight into the antimicrobial mechanisms of copper at the single cell level, and can be applied to design of better metallic antimicrobial materials as well as investigate different microorganisms. PMID:27258941

  15. ANTIMICROBIAL PROPERTIES OF ARECA CATECHU (ARECA NUT HUSK EXTRACTS AGAINST COMMON ORAL PATHOGENS

    Directory of Open Access Journals (Sweden)

    Maria Bobby Cyriac

    2012-02-01

    Full Text Available The husk fibres of Areca catechu (areca nut are reported to be used by the people of rural areas of Dakshina Kannada, Karnataka for cleaning their teeth. The beneficial effects of these plant materials are not scientifically proven, so the study was carried out to estimate the antimicrobial properties of A.catechu against common oral pathogens. These antimicrobial properties in addition to mechanical cleansing property of the fibers of areca nut could improve the oral health. Alcoholic and aqueous extracts of husk of Areca catechu were prepared and antimicrobial properties against common oral pathogens like Streptococcus mutans, Streptococcus salivarius, Streptococcus mitis, Lactobacillus acidophilus, Candida albicans, Prevotella intermedia were performed by agar well diffusion method. Alcoholic extract of Areca catechu husk fibers showed dose dependent positive inhibitory effect against Candida albicans with zone of inhibition of 5-9 mm. Alcoholic and aqueous extracts did not show significant antimicrobial activity against other tested organisms. As our study failed to demonstrate significant inhibitory effect on cariogenic organisms and a periodontal pathogen, we conclude that areca husk when used for routine oral care, would improve the oral health primarily through mechanical cleansing rather than antimicrobial activity. However, the results indicate that areca husk contains chemical components that has antifungal effect. Therefore this plant material can be a potential source for developing natural antifungal agents against C. albicans which is a common oral pathogen.

  16. Challenges while Updating Planning Parameters of an ERP System and How a Simulation-Based Support System Can Support Material Planners

    Directory of Open Access Journals (Sweden)

    Ulrike Stumvoll

    2016-01-01

    Full Text Available In an Enterprise Resource Planning (ERP system, production planning is influenced by a variety of parameters. Previous investigations show that setting parameter values is highly relevant to a company’s target system. Parameter settings should be checked and adjusted, e.g., after a change in environmental factors, by material planners. In practice, updating the parameters is difficult due to several reasons. This paper presents a simulation-based decision support system, which helps material planners in all stages of decision-making processes. It will present the system prototype’s user interface and the results of applying the system to a case study.

  17. Moderation of Stimulus Material on the Prediction of IQ with Infants' Performance in the Visual Expectation Paradigm: Do Greebles Make the Task More Challenging?

    Science.gov (United States)

    Teubert, Manuel; Lohaus, Arnold; Fassbender, Ina; Vöhringer, Isabel A.; Suhrke, Janina; Poloczek, Sonja; Freitag, Claudia; Lamm, Bettina; Teiser, Johanna; Keller, Heidi; Knopf, Monika; Schwarzer, Gudrun

    2015-01-01

    The objective of this study was to examine the role of the stimulus material for the prediction of later IQ by early learning measures in the Visual Expectation Paradigm (VExP). The VExP was assessed at 9?months using two types of stimuli, Greebles and human faces. Greebles were assumed to be associated with a higher load on working memory in…

  18. Human Antimicrobial Peptides and Proteins

    Directory of Open Access Journals (Sweden)

    Guangshun Wang

    2014-05-01

    Full Text Available As the key components of innate immunity, human host defense antimicrobial peptides and proteins (AMPs play a critical role in warding off invading microbial pathogens. In addition, AMPs can possess other biological functions such as apoptosis, wound healing, and immune modulation. This article provides an overview on the identification, activity, 3D structure, and mechanism of action of human AMPs selected from the antimicrobial peptide database. Over 100 such peptides have been identified from a variety of tissues and epithelial surfaces, including skin, eyes, ears, mouths, gut, immune, nervous and urinary systems. These peptides vary from 10 to 150 amino acids with a net charge between −3 and +20 and a hydrophobic content below 60%. The sequence diversity enables human AMPs to adopt various 3D structures and to attack pathogens by different mechanisms. While α-defensin HD-6 can self-assemble on the bacterial surface into nanonets to entangle bacteria, both HNP-1 and β-defensin hBD-3 are able to block cell wall biosynthesis by binding to lipid II. Lysozyme is well-characterized to cleave bacterial cell wall polysaccharides but can also kill bacteria by a non-catalytic mechanism. The two hydrophobic domains in the long amphipathic α-helix of human cathelicidin LL-37 lays the basis for binding and disrupting the curved anionic bacterial membrane surfaces by forming pores or via the carpet model. Furthermore, dermcidin may serve as ion channel by forming a long helix-bundle structure. In addition, the C-type lectin RegIIIα can initially recognize bacterial peptidoglycans followed by pore formation in the membrane. Finally, histatin 5 and GAPDH(2-32 can enter microbial cells to exert their effects. It appears that granulysin enters cells and kills intracellular pathogens with the aid of pore-forming perforin. This arsenal of human defense proteins not only keeps us healthy but also inspires the development of a new generation of personalized

  19. Antimicrobial Activity of Drosera rotundifolia L.

    Directory of Open Access Journals (Sweden)

    Miroslava Kačániová

    2014-11-01

    Full Text Available Droseracae spp. is widely used in folk medicine. In the present study, the antimicrobial activities of the four Drosera rotundifolia L. (D8.11, D15.12, 18.10, 8.11 samples were investigated. The antimicrobial activities were determined by using agar disc diffusion method against grampositive bacteria (Bacillus thurigiensis, Staphylococcus aureus, Listeria monocytogenes and gramnegative bacteria (Yersinia enterocolitica, Salmonella enteritidis.  The results of the disk diffusion method showed very different activity against all tested strains of microorganisms. The best antimicrobial activity of ethanolic extract Drosera rotundifolia L. against Salmonella enteritidis was found at Drosera rotundifolia (D8.11.

  20. Comparative evaluation of antimicrobials for textile applications.

    Science.gov (United States)

    Windler, Lena; Height, Murray; Nowack, Bernd

    2013-03-01

    Many antimicrobial technologies are available for textiles. They may be used in many different textile applications to prevent the growth of microorganisms. Due to the biological activity of the antimicrobial compounds, the assessment of the safety of these substances is an ongoing subject of research and regulatory scrutiny. This review aims to give an overview on the main compounds used today for antimicrobial textile functionalization. Based on an evaluation of scientific publications, market data as well as regulatory documents, the potential effects of antimicrobials on the environment and on human health were considered and also life cycle perspectives were taken into account. The characteristics of each compound were summarized according to technical, environmental and human health criteria. Triclosan, silane quaternary ammonium compounds, zinc pyrithione and silver-based compounds are the main antimicrobials used in textiles. The synthetic organic compounds dominate the antimicrobials market on a weight basis. On the technical side the application rates of the antimicrobials used to functionalize a textile product are an important parameter with treatments requiring lower dosage rates offering clear benefits in terms of less active substance required to achieve the functionality. The durability of the antimicrobial treatment has a strong influence on the potential for release and subsequent environmental effects. In terms of environmental criteria, all compounds were rated similarly in effective removal in wastewater treatment processes. The extent of published information about environmental behavior for each compound varies, limiting the possibility for an in-depth comparison of all textile-relevant parameters across the antimicrobials. Nevertheless the comparative evaluation showed that each antimicrobial technology has specific risks and benefits that should be taken into account in evaluating the suitability of different antimicrobial products. The

  1. Silver-containing antimicrobial membrane based on chitosan-TPP hydrogel for the treatment of wounds.

    Science.gov (United States)

    Sacco, Pasquale; Travan, Andrea; Borgogna, Massimiliano; Paoletti, Sergio; Marsich, Eleonora

    2015-03-01

    Treatment of non-healing wounds represents hitherto a severe dilemma because of their failure to heal caused by repeated tissue insults, bacteria contamination and altered physiological condition. This leads to face huge costs for the healthcare worldwide. To this end, the development of innovative biomaterials capable of preventing bacterial infection, of draining exudates and of favoring wound healing is very challenging. In this study, we exploit a novel technique based on the slow diffusion of tripolyphosphate for the preparation of macroscopic chitosan hydrogels to obtain soft pliable membranes which include antimicrobial silver nanoparticles (AgNPs) stabilized by a lactose-modified chitosan (Chitlac). UV-Vis and TEM analyses demonstrated the time stability and the uniform distribution of AgNPs in the gelling mixture, while swelling studies indicated the hydrophilic behavior of membrane. A thorough investigation on bactericidal properties of the material pointed out the synergistic activity of chitosan and AgNPs to reduce the growth of S. aureus, E. coli, S. epidermidis, P. aeruginosa strains and to break apart mature biofilms. Finally, biocompatibility assays on keratinocytes and fibroblasts did not prove any harmful effects on the viability of cells. This novel technique enables the production of bioactive membranes with great potential for the treatment of non-healing wounds. PMID:25693676

  2. The Concrete and Pavement Challenge

    Science.gov (United States)

    Roman, Harry T.

    2012-01-01

    The modern world is characterized by the extensive use of concrete and asphalt pavement. Periodically, these materials are replaced and the old materials disposed of. In this challenge, students will be asked to develop ways to reuse the old materials. It is important for students to understand how concrete and asphalt are made and applied, as…

  3. Preparation and Activity of a Nanometer Anti-microbial Polyurethane

    Institute of Scientific and Technical Information of China (English)

    GUAN Yanqing; TAO Huimin; LI Yuechuan; WANG Wenwen; LI Zhibin; PENG Changlian

    2009-01-01

    A novel way for photo-immobilization with interferon-α(IFN-α)on the surface of polyurethane(PU)material,which makes PU condom more effective function in the future,was investigated.A kind of photoactive arylazide-4-azidobenzoic acid was modified to IFN-α with the confirmation of IR and Raman spectrum.Micro morphology of the photo-immobilized cell factors was observed by FESEM as well as CSLM at the level of nanometer.Finally,the product with ele-mentary test of anti-microbial was also evaluated.

  4. The impact of antimicrobial allergy labels on antimicrobial usage in cancer patients

    OpenAIRE

    Trubiano, Jason A; Leung, Vivian K.; Chu, Man Y.; Leon J. Worth; Slavin, Monica A.; Thursky, Karin A

    2015-01-01

    Background Antibiotic allergy labels are associated with sub-optimal prescribing patterns and poorer clinical outcomes in non-cancer populations, but the effect of labelling on antimicrobial usage in patients with cancer is unknown. Findings A retrospective review of hospitalized patients admitted to the Peter MacCallum Cancer Centre (2010-2012) identified 23 % of cancer patients (n = 198) with an antimicrobial allergy label (AA). Comparison of those with an antimicrobial allergy label to tho...

  5. Antimicrobial properties of chitosan-poly (vinyl alcohol) films containing dragon blood extract

    International Nuclear Information System (INIS)

    Hydro alcoholic, alcoholic and aqueous Dragon's blood (Croton lechleri) extracts were introduced in gamma irradiated chitosan-poly (vinyl alcohol) films and their antimicrobial properties against Staphylococcus aureus, Escherichia coli y Pseudomonas aeruginosa have been evaluated. These films as well as the latex exhibit activity against S. aureus only and have potential application as wound healing material. (author)

  6. TESTING ANTIMICROBIAL PAINT EFFICACY ON GYPSUM WALLBOARD CONTAMINATED WITH STACHYBOTRYS CHARTARUM

    Science.gov (United States)

    Often mold contaminated building materials are not properly removed, some surface cleaning is performed and paint is applied in an attempt to alleviate the problem. The efficacy of antimicrobial paints to eliminate or control mold regrowth on surfaces can easily be tested on non-...

  7. TESTING ANTIMICROBIAL CLEANER EFFICACY ON GYPSUM WALLBOARD CONTAMINATED WITH STACHYBOTRYS CHARTARUM

    Science.gov (United States)

    Reducing occupant exposure to indoor mold growth is the goal of this research, through the efficacy testing of antimicrobial cleaners. Often mold contaminated building materials are not properly removed, but instead surface cleaners are applied in an attempt to alleviate the prob...

  8. Antimicrobial dihydroisocoumarins from Crassocephalum biafrae.

    Science.gov (United States)

    Tabopda, Turibio K; Fotso, Gislain W; Ngoupayo, Joseph; Mitaine-Offer, Anne-Claire; Ngadjui, Bonaventure T; Lacaille-Dubois, Marie-Aleth

    2009-09-01

    Bioassay-guided fractionation of the CHCl (3)-soluble extract of the stem bark of Crassocephalum biafrae (Asteraceae) resulted in the isolation of three new dihydroisocoumarins, named biafraecoumarins A ( 1), B ( 2), and C ( 3); two known triterpenes ( 4 and 5); and a known ceramide ( 6). The structures of the new compounds were established as 7-but-15-enyl-6,8-dihydroxy-3( R)-penta-9,11-dienylisochroman-1-one ( 1), 7-butyl-6,8-dihydroxy-3( R)-penta-9,11-dienylisochroman-1-one ( 2), and 7-butyl-6,8-dihydroxy-3( R)-pent-10-enylisochroman-1-one ( 3) using spectroscopic data. Compounds 1- 3 exhibit low to significant antimicrobial activities against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Pseudomonas picketti, Trichphyton longifusus, Aspergillus flavus, Microsporum canis, Fusarium solani, Candida albicans, and Candida glabrata. PMID:19350487

  9. Antimicrobial activity of benzylisoquinoline alkaloids.

    Science.gov (United States)

    Villar, A; Mares, M; Rios, J L; Canton, E; Gobernado, M

    1987-04-01

    The antimicrobial in vitro activity of 14 benzylisoquinoline alkaloids was investigated by agar diffusion and agar dilution methods against several genera of microorganisms that included Streptococcus, Staphylococcus, Bacillus, Lysteria, Escherichia, Salmonella, Klebsiella, Pseudomonas, Enterobacter, Serratia, Shigella, Mycobacterium and Candida. Anolobine was the most active compound against grampositive bacteria with MIC90 between 12 and 50 mg/l; less active were anonaine, lysicamine and liriodenine. All the alkaloids of the noraporphine and oxoaporphine groups, with the exception of isopiline, showed activity against Mycobacterium phlei (MIC 6-25 mg/l). Candida albicans ATCC26555 was inhibited by anonaine, nornantenine and xylopine (MIC 3-12 mg/l). None of the alkaloids tested had a significant activity against gramnegative rods. The action against susceptible microorganisms was bactericidal. PMID:3615557

  10. Antimicrobial activities of Barringtonia acutangula.

    Science.gov (United States)

    Rahman, M Mukhlesur; Polfreman, David; MacGeachan, Jodie; Gray, Alexander I

    2005-06-01

    Crude extracts and VLC fractions from the stem bark of Barringtonia acutangula (L.) Gaertn (Fam. Lecythidaceae) were screened for their antimicrobial activities against two Gram-positive bacteria, two Gram-negative bacteria and two fungi using a microdilution titre assay. Among the crude extracts, petroleum ether extract showed good activity against all test organisms. The VLC fraction PE 16 was found to be very effective against Bacillus subtilis (MIC=25 microg/ml) and Aspergillus niger (MIC=12.5 microg/ml). The activities were compared to standard antibiotics-kanamycin and fluconazole. The major compound from PE16 was identified as 12, 20(29)-lupadien-3-ol by NMR spectroscopy. PMID:16114086

  11. Comparative Evaluation of the Antimicrobial Activity of Different Antimicrobial Peptides against a Range of Pathogenic Bacteria

    DEFF Research Database (Denmark)

    Ebbensgaard, Anna Elisabeth; Mordhorst, Hanne; Overgaard, Michael Toft;

    2015-01-01

    The rapid emergence of resistance to classical antibiotics has increased the interest in novel antimicrobial compounds. Antimicrobial peptides (AMPs) represent an attractive alternative to classical antibiotics and a number of different studies have reported antimicrobial activity data of various...... AMPs, but there is only limited comparative data available. The mode of action for many AMPs is largely unknown even though several models have suggested that the lipopolysaccharides (LPS) play a crucial role in the attraction and attachment of the AMP to the bacterial membrane in Gram...... among the different peptides. Further, the antimicrobial activity of a selection of cationic AMPs was investigated in various E. coli LPS mutants....

  12. An antimicrobial stewardship program reduces antimicrobial therapy duration and hospital stay in surgical wards.

    Science.gov (United States)

    Güerri-Fernández, R; Villar-García, J; Herrera-Fernández, S; Trenchs-Rodríguez, M; Fernández-Morato, J; Moro, L; Sancho, J; Grande, L; Clará, A; Grau, S; Horcajada, J P

    2016-06-01

    We report a quasi-experimental study of the implementation of an antimicrobial stewardship program in two surgical wards, with a pre-intervention period with just assessment of prescription and an intervention period with a prospective audit on antibiotic prescription model. There was a significant reduction of length of stay and the total days of antimicrobial administration. There were no differences in mortality between groups. The antimicrobial stewardship program led to the early detection of inappropriate empirical antibiotic treatment and was associated with a significant reduction in length of stay and the total duration of antimicrobial therapy. PMID:27167764

  13. Optimizing antimicrobial therapy in children.

    Science.gov (United States)

    Long, Sarah S

    2016-07-01

    Management of common infections and optimal use of antimicrobial agents are presented, highlighting new evidence from the medical literature that enlightens practice. Primary therapy of staphylococcal skin abscesses is drainage. Patients who have a large abscess (>5 cm), cellulitis or mixed abscess-cellulitis likely would benefit from additional antibiotic therapy. When choosing an antibiotic for outpatient management, the patient, pathogen and in vitro drug susceptibility as well as tolerability, bioavailability and safety characteristics of antibiotics should be considered. Management of recurrent staphylococcal skin and soft tissue infections is vexing. Focus is best placed on reducing density of the organism on the patient's skin and in the environment, and optimizing a healthy skin barrier. With attention to adherence and optimal dosing, acute uncomplicated osteomyelitis can be managed with early transition from parenteral to oral therapy and with a 3-4 week total course of therapy. Doxycycline should be prescribed when indicated for a child of any age. Its use is not associated with dental staining. Azithromycin should be prescribed for infants when indicated, whilst being alert to an associated ≥2-fold excess risk of pyloric stenosis with use under 6 weeks of age. Beyond the neonatal period, acyclovir is more safely dosed by body surface area (not to exceed 500 mg/m(2)/dose) than by weight. In addition to the concern of antimicrobial resistance, unnecessary use of antibiotics should be avoided because of potential later metabolic effects, thought to be due to perturbation of the host's microbiome. PMID:27263076

  14. The quality of outpatient antimicrobial prescribing

    DEFF Research Database (Denmark)

    Malo, Sara; Bjerrum, Lars; Feja, Cristina;

    2013-01-01

    The aim of the study was to analyse and compare the quality of outpatient antimicrobial prescribing in Denmark and Aragón (in northeastern Spain), with the objective of assessing inappropriate prescribing....

  15. Antimicrobial susceptibility pattern of Helicobacter suis strains.

    Science.gov (United States)

    Vermoote, Miet; Pasmans, Frank; Flahou, Bram; Van Deun, Kim; Ducatelle, Richard; Haesebrouck, Freddy

    2011-12-15

    Helicobacter suis is a very fastidious porcine gastric pathogen, which is also considered to be of zoonotic importance. In vitro antimicrobial susceptibility cannot be determined using standard assays, as this agent only grows in a biphasic medium with an acidic pH. Therefore, a combined agar and broth dilution method was used to analyse the activity of nine antimicrobial agents against nine H. suis isolates. After 48 h microaerobic incubation, minimal inhibitory concentrations (MICs) were determined by software-assisted calculation of bacterial growth. Only for enrofloxacin a bimodal distribution of MICs was demonstrated, indicating acquired resistance in one strain, which showed an AGT→AGG (Ser→Arg) substitution at codon 99 of gyrA. In conclusion, the assay developed here is suitable for determination of the antimicrobial susceptibility of H. suis isolates, although activity of acid sensitive antimicrobial agents may be higher than predicted from MIC endpoints. PMID:21733643

  16. SecA inhibitors: next generation antimicrobials

    Institute of Scientific and Technical Information of China (English)

    Weixuan Chen; Arpana Chaudhary; Jianmei Cui; Jinshan Jin; Yinghsin Hsieh; Hsiuchin Yang; Yingju Huang; Phang C. Tai; Binghe Wang

    2012-01-01

    Health problems caused by bacterial infection have become a major public health concern in recent years due to the widespread emergence of drug-resistant bacterial strains.Therefore,the need for the development of new types of antimicrobial agents,especially those with a novel mechanism of action,is urgent.SecA,one of the key components of the secretion (Sec) pathway,is a new promising target for antimicrobial agent design.In recent years,promising leads targeting SecA have been identified and the feasibility of developing antimicrobial agents through the inhibition of SecA has been demonstrated.We hope this review will help stimulate more research in this area so that new antimicrobials can be obtained by targeting SecA.

  17. ANTIMICROBIAL ACTIVITY OF LACTIC ACID BACTERIAL ISOLATES

    Directory of Open Access Journals (Sweden)

    Utkarsha S. Shivsharan

    2013-08-01

    Full Text Available Micro-organisms have tendency to produce antimicrobial substances which show biological activity against other kind of micro-organisms. This phenomenon of bacterial antagonism is observed in lactic acid bacteria with competitive advantages. The lactic acid bacteria are commonly present in many fermented products, fruits and milk products. The variety of antimicrobial substances produced by lactic acid bacteria showing good inhibition capacity include production of lactic acid, acetic acid, hydrogen peroxide, carbon dioxide, diacetyl and bacteriocin. Bacteriocins produced by lactic acid bacteria are the subject of intense research because of their antimicrobial activity against food born bacteria such as Listeria monocytogenes, staphylococcus aureus, Bacillus cereus, Clostridium botulinum and several others .Bacteriocins may be bacteriostatic or bactericidal with narrow or broad range of activity. The main of the study was to study the antimicrobial activity of such lactic acid bacterial isolates.

  18. Antimicrobial activity of UMFix tissue fixative

    OpenAIRE

    Cleary, T J; Morales, A. R.; Nadji, M.; Nassiri, M.; Vincek, V.

    2005-01-01

    Aims: The aim of this study was to determine the antimicrobial effects of UMFix, an alcohol based tissue fixative, on various microorganisms. The UMFix solution was compared with 10% neutral buffered formalin.

  19. Antimicrobial activity of some Iranian medicinal plants

    Directory of Open Access Journals (Sweden)

    Ghasemi Pirbalouti Abdollah

    2010-01-01

    Full Text Available The major aim of this study was to determine the antimicrobial activity of the extracts of eight plant species which are endemic in Iran. The antimicrobial activities of the extracts of eight Iranian traditional plants, including Hypericum scabrum, Myrtus communis, Pistachia atlantica, Arnebia euchroma, Salvia hydrangea, Satureja bachtiarica, Thymus daenensis and Kelussia odoratissima, were investigated against Escherichia coli O157:H7, Bacillus cereus, Listeria monocytogenes and Candida albicans by agar disc diffusion and serial dilution assays. Most of the extracts showed a relatively high antimicrobial activity against all the tested bacteria and fungi. Of the plants studied, the most active extracts were those obtained from the essential oils of M. communis and T. daenensis. The MIC values for active extract and essential oil ranged between 0.039 and 10 mg/ml. It can be said that the extract and essential oil of some medicinal plants could be used as natural antimicrobial agents in food preservation. .

  20. Heritage materials and biofouling mitigation through UV-C irradiation in show caves: state-of-the-art practices and future challenges.

    Science.gov (United States)

    Borderie, Fabien; Alaoui-Sossé, Badr; Aleya, Lotfi

    2015-03-01

    Biofouling, i.e., colonization of a given substrate by living organisms, has frequently been reported for heritage materials and particularly on stone surfaces such as building facades, historical monuments, and artworks. This also concerns subterranean environments such as show caves, in which the installation of artificial light for tourism has led to the proliferation of phototrophic microorganisms. In Europe nowadays, the use of chemicals in these very sensitive environments is scrutinized and regulated by the European Union. New and environmentally friendly processes must be developed as alternative methods for cave conservation. For several years, the UV irradiation currently used in medical facilities and for the treatment of drinking water has been studied as a new innovative method for the conservation of heritage materials. This paper first presents a review of the biofouling phenomena on stone materials such as building facades and historical monuments. The biological disturbances induced by tourist activity in show caves are then examined, with special attention given to the methods and means to combat them. Thirdly, a general overview is given of the effects of UV-C on living organisms, and especially on photosynthetic microorganisms, through different contexts and studies. Finally, the authors' own experiments and findings are presented concerning the study and use of UV-C irradiation to combat algal proliferation in show caves. Both laboratory and in situ results are summarized and synthesized from their previously published works. The application of UV in caves is discussed and further experiments are proposed to enhance research in this domain. PMID:25548019

  1. Public health measures to control the spread of antimicrobial resistance in Neisseria gonorrhoeae in men who have sex with men

    NARCIS (Netherlands)

    Xiridou, M; Soetens, L C; Koedijk, F D H; VAN DER Sande, M A B; Wallinga, J

    2015-01-01

    Gonorrhoea is one of the most common sexually transmitted infections. The control of gonorrhoea is extremely challenging because of the repeated development of resistance to the antibiotics used for its treatment. We explored different strategies to control the spread of antimicrobial resistance and

  2. Matrix Organization and Merit Factor Evaluation as a Method to Address the Challenge of Finding a Polymer Material for Roll Coated Polymer Solar Cells

    DEFF Research Database (Denmark)

    Bundgaard, Eva; Livi, Francesco; Hagemann, Ole;

    2015-01-01

    The results presented demonstrate how the screening of 104 light-absorbing low band gap polymers for suitability in roll coated polymer solar cells can be accomplished through rational synthesis according to a matrix where 8 donor and 13 acceptor units are organized in rows and columns. Synthesis...... silver comb back electrode structure. The matrix organization enables fast identification of active layer materials according to a weighted merit factor that includes more than simply the power conversion efficiency and is used as a method to identify the lead candidates. Based on several characteristics...

  3. Antimicrobial activity of Aspilia latissima (Asteraceae)

    OpenAIRE

    Souza, Jeana M.E.; Chang, Marilene R.; Brito, Daniela Z.; Katyuce S. Farias; Damasceno-Junior, Geraldo A.; Izabel C.C. Turatti; Norberto P. Lopes; Santos, Edson A.; Carollo, Carlos A.

    2015-01-01

    Abstract We evaluated the antimicrobial activity of Aspilia latissima - an abundant plant from the Brazilian Pantanal region - against Candida albicans, Candida parapsilosis, Candida krusei, Candida tropicalis, Pseudomonas aeruginosa, Enterococcus faecalis, Escherichia coli and Staphylococcus aureus. The crude extracts and fractions showed activity in all tested microorganisms. The chloroform fraction of the leaves and roots showed the most antimicrobial activity against S. aureus, with an MI...

  4. Antimicrobial Activity of Drosera rotundifolia L.

    OpenAIRE

    Miroslava Kačániová; Dominika Ďurechová; Nenad Vuković; Attila Kántor; Jana Petrová; Lukáš Hleba; Alexander Vatľák

    2014-01-01

    Droseracae spp. is widely used in folk medicine. In the present study, the antimicrobial activities of the four Drosera rotundifolia L. (D8.11, D15.12, 18.10, 8.11) samples were investigated. The antimicrobial activities were determined by using agar disc diffusion method against grampositive bacteria (Bacillus thurigiensis, Staphylococcus aureus, Listeria monocytogenes) and gramnegative bacteria (Yersinia enterocolitica, Salmonella enteritidis).  The results of the disk diffusion method show...

  5. Phytochemical and Antimicrobial Studies of Chlorophytum borivilianum

    OpenAIRE

    Guno Sindhu Chakraborthy; Vidhu Aeri

    2009-01-01

    Extracts of leaves and stems of Chlorophytum borivilianum were subjected to preliminary phytochemical screening and in-vitro antimicrobial studies. The results of the preliminary investigation revealed the presence of alkaloids, glycosides, steroidal nucleus, saponins and tannins in both parts. The methanolic extract of leaf and stems part were investigated for antimicrobial activity using agar disc diffusion method. Six clinical strains of human pathogenic microorganisms, comprising 3 Gram +...

  6. Leaves Antimicrobial Activity of Glycyrrhiza glabra L.

    OpenAIRE

    Irani, Mahboubeh; Sarmadi, Marziyeh; Bernard, Françoise; Ebrahimi pour, Gholam Hossein; Shaker Bazarnov, Hossein

    2010-01-01

    Licorice (Glycyrrhiza glabra L.) is an important medicinal plant. In this study, the antimicrobial activities of ethanolic and aqueous extracts from licorice leaves were studied compared to root extracts activities. Bacillus subtilis, Enterococcus faecalis, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Escherichia coli, and Candida albicans were used as test organisms. Antimicrobial activity was tested by paper disc agar diffusion and serial dilution methods in orde...

  7. Optimizing antimicrobial therapy in critically ill patients

    OpenAIRE

    Pagani, Leonardo

    2014-01-01

    Virginie Vitrat,1 Serge Hautefeuille,2 Cécile Janssen,1 David Bougon,2 Michel Sirodot,2 Leonardo Pagani1,3 1Antimicrobial Stewardship Program, Infectious Diseases Unit, 2Intensive Care Unit, Annecy-Genevois Hospital Center (CHANGE), Annecy, France; 3Infectious Diseases Unit, Bolzano Central Hospital, Bolzano, Italy Abstract: Critically ill patients with infection in the intensive care unit (ICU) would certainly benefit from timely bacterial identification and effective antimicrobi...

  8. Optimizing antimicrobial therapy in critically ill patients

    OpenAIRE

    Vitrat V; Hautefeuille S; Janssen C; Bougon D; Sirodot M; Pagani L

    2014-01-01

    Virginie Vitrat,1 Serge Hautefeuille,2 Cécile Janssen,1 David Bougon,2 Michel Sirodot,2 Leonardo Pagani1,3 1Antimicrobial Stewardship Program, Infectious Diseases Unit, 2Intensive Care Unit, Annecy-Genevois Hospital Center (CHANGE), Annecy, France; 3Infectious Diseases Unit, Bolzano Central Hospital, Bolzano, Italy Abstract: Critically ill patients with infection in the intensive care unit (ICU) would certainly benefit from timely bacterial identification and effective antimicrobial t...

  9. The antimicrobial activity of Physalis peruviana L.

    OpenAIRE

    Göztok, Ferda; Zengin, Fikriye

    2013-01-01

    In this study, the antimicrobial activity of Physalis peruviana L. was investigated. The antimicrobial activity was evaluated according to the microdilution method by using Bacillus megaterium DMS 32, Pseudomonas aeruginosa DMS 50071, Escherichia coli ATCC 25922, Klebsiella pneumoniae FMC 5, Proteus vulgaris FMC 1, Enterobacter aeregenes CCM 2531, Candida albicans FMC 17, Candida globrata ATCC 66032, Candida tropicalis ATCC 13803, Trichophyton sp. and Epidermaphyton sp. In the end of experim...

  10. Mechanism of action of cyclic antimicrobial peptides

    OpenAIRE

    Díaz i Cirac, Anna

    2011-01-01

    This PhD thesis is the result of the combination of experimental and computational techniques with the aim of understanding the mechanism of action of de novo cyclic decapeptides with high antimicrobial activity. By experimental techniques the influence of the replacement of the phenylalanine for tryptophan residue in their antimicrobial activity was tested and the stability in human serum was also analyzed, in order to evaluate their potential therapeutic application as antitumor agents. ...

  11. Antimicrobial activity of some Iranian medicinal plants

    OpenAIRE

    Ghasemi Pirbalouti Abdollah; Jahanbazi Parvin; Enteshari Shekoofeh; Malekpoor Fatemeh; Hamedi Behzad

    2010-01-01

    The major aim of this study was to determine the antimicrobial activity of the extracts of eight plant species which are endemic in Iran. The antimicrobial activities of the extracts of eight Iranian traditional plants, including Hypericum scabrum, Myrtus communis, Pistachia atlantica, Arnebia euchroma, Salvia hydrangea, Satureja bachtiarica, Thymus daenensis and Kelussia odoratissima, were investigated against Escherichia coli O157:H7, Bacillus cereus, Listeria monocytogenes and Candida albi...

  12. Antimicrobial activity of peach and grapevine defensins

    OpenAIRE

    Nanni, Valentina

    2012-01-01

    Antimicrobial peptides (AMPs) are an important component of the innate immune system of the plants. Plant defensins are a large family of antimicrobial peptides with several interesting features, such as small dimension, high stability and broad spectrum of action. The discovery of new molecules and the study of their mechanism of action allow to consider them attractive for biotechnological applications. In this PhD thesis a defensin from Prunus persica (PpDFN1) and four novel DEFensin Li...

  13. Seaweed extracts as antimicrobial agents in aquaculture

    OpenAIRE

    Vatsos, Ioannis N.; Rebours, Celine

    2014-01-01

    In the last 20 years, there has been an increasing interest in using various seaweed extracts as prophylactic and/or therapeutic agents in aquaculture. Up until now, most studies on the direct antimicrobial effect of seaweeds have taken place in various parts of Asia, particularly in India. All groups of seaweeds exhibit significant antimicrobial properties against many infectious agents of fish and shrimp, but the genera that appear to exhibit a broader range of antibacterial proper...

  14. Antimicrobial activity of amazonian medicinal plants

    OpenAIRE

    Oliveira, Amanda A; Segovia, Jorge FO; Sousa, Vespasiano YK; Mata, Elida CG; Gonçalves, Magda CA; Bezerra, Roberto M; Junior, Paulo OM; Kanzaki, Luís IB

    2013-01-01

    Objectives The aqueous extracts of currently utilized Amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms. Methods Medium resuspended lyophilized aqueous extracts of different organs of Amazonian medicinal plants were assayed by in vitro screening for antimicrobial activity. ATCC and standardized microorganisms obtained from Oswaldo Cruz Foundation/Brazil were individually and homogeneously grown in agar plat...

  15. Logistical challenges

    Directory of Open Access Journals (Sweden)

    Steve Matthews

    2005-07-01

    Full Text Available The impact of the Asian tsunami was unprecedented and the logistical challenges of meeting the needs of those affected were enormous. Had the tsunami happened even five years ago, World Vision would not have been able to respond nearly as effectively as it did.

  16. Mobility Challenges

    DEFF Research Database (Denmark)

    Jensen, Ole B.; Lassen, Claus

    2011-01-01

    This article takes point of departure in the challenges to understand the importance of contemporary mobility. The approach advocated is a cross-disciplinary one drawing on sociology, geography, urban planning and design, and cultural studies. As such the perspective is to be seen as a part of th...

  17. Ethical Challenges

    Science.gov (United States)

    Morris, Michael

    2004-01-01

    All evaluators face the challenge of striving to adhere to the highest possible standards of ethical conduct. Translating the AEA's Guiding Principles and the Joint Committee's Program Evaluation Standards into everyday practice, however, can be a complex, uncertain, and frustrating endeavor. Moreover, acting in an ethical fashion can require…

  18. Editorial Challenges

    OpenAIRE

    Budin, Wendy C.

    2008-01-01

    In this column, the editor of The Journal of Perinatal Education (JPE) discusses some of the challenges involved in becoming the new editor of JPE. The editor also describes the contents of this issue, which offer a broad range of resources, research, and inspiration for childbirth educators in their efforts to promote normal birth.

  19. Archiving challenges

    OpenAIRE

    Ringersma, J.

    2010-01-01

    Teaching slides on: What is a digital archive? Parties involved in digital archiving Archiving challenges organization of data coherence and persistency access and safety Language archiving software Different users, different needs For: Saami Language Documentation and Revitalization. Winter school, Bodø, Norway

  20. Antimicrobial peptides on calcium phosphate-coated titanium for the prevention of implant-associated infections

    DEFF Research Database (Denmark)

    Kazemzadeh-Narbat, Mehdi; Kindrachuk, Jason; Duan, Ke;

    2010-01-01

    ) bacteria with 106-fold reductions of both bacterial strains within 30 min as assessed by measuring colony-forming units (CFU). Repeated CFU assays on the same CaP-Tet213 specimen demonstrated retention of antimicrobial activity by the CaP-Tet213 surfaces through four test cycles. The susceptibility of......Prevention of implant-associated infections has been one of the main challenges in orthopaedic surgery. This challenge is further complicated by the concern over the development of antibiotic resistance as a result of using traditional antibiotics for infection prophylaxis. The objective of this...... study was to develop a technique that enables the loading and local delivery of a unique group of cationic antimicrobial peptides (AMP) through implant surfaces. A thin layer of micro-porous calcium phosphate (CaP) coating was processed by electrolytic deposition onto the surface of titanium as the drug...

  1. Quorum sensing inhibitory drugs as next generation antimicrobials: worth the effort?

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, Michael Christian

    2008-01-01

    Bacterial resistance poses a major challenge to the development of new antimicrobial agents. Conventional antibiotics have an inherent obsolescence because they select for development of resistance. Bacterial infections have again become a serious threat in developed countries. Particularly...... biofilms are more tolerant to antibiotics than their planktonic counterparts. Therefore, research should identify new antimicrobial agents and their corresponding targets to decrease the biofilm-forming capability or persistence of the infectious bacteria. Here, we review one such drug target: bacterial......, elderly, immunocompromised, and hospitalized patients are susceptible to infections caused by bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. These bacteria form chronic, biofilm-based infections, which are challenging because bacterial cells living as...

  2. Antimicrobial Activity of Starch Hydrogel Incorporated with Copper Nanoparticles.

    Science.gov (United States)

    Villanueva, María Emilia; Diez, Ana María Del Rosario; González, Joaquín Antonio; Pérez, Claudio Javier; Orrego, Manuel; Piehl, Lidia; Teves, Sergio; Copello, Guillermo Javier

    2016-06-29

    In order to obtain an antimicrobial gel, a starch-based hydrogel reinforced with silica-coated copper nanoparticles (Cu NPs) was developed. Cu NPs were synthesized by use of a copper salt and hydrazine as a reducing agent. In order to enhance Cu NP stability over time, they were synthesized in a starch medium followed by a silica coating. The starch hydrogel was prepared by use of urea and water as plasticizers and it was treated with different concentrations of silica-coated copper nanoparticles (Si-Cu NPs). The obtained materials were characterized by Fourier transform infrared (FT-IR) spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, scanning electron microscopy (SEM), and rheometry. FT-IR and EPR spectra were used for characterization of Cu NPs and Si-Cu NPs, confirming that a starch cap was formed around the Cu NP and demonstrating the stability of the copper nanoparticle after the silica coating step. SEM images showed Cu NP, Si-Cu NP, and hydrogel morphology. The particle size was polydisperse and the structure of the gels changed along with particle concentration. Increased NP content led to larger pores in starch structure. These results were in accordance with the rheological behavior, where reinforcement by the Si-Cu NP was seen. Antimicrobial activity was evaluated against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacterial species. The hydrogels were demonstrated to maintain antimicrobial activity for at least four cycles of use. A dermal acute toxicity test showed that the material could be scored as slightly irritant, proving its biocompatibility. With these advantages, it is believed that the designed Si-Cu NP loaded hydrogel may show high potential for applications in various clinical fields, such as wound dressings and fillers. PMID:27295333

  3. In vitro antimicrobial activity of methanolic leaf extract of Psidium guajava L.

    Directory of Open Access Journals (Sweden)

    Anju Dhiman

    2011-01-01

    Full Text Available Aim: This study was designed to examine the chemical composition and in vitro antimicrobial potential of methanolic extract of Psidium guajava Linn (Myrtaceae. Materials and Methods: The inhibitory effect of methanolic extract of P. guajava was tested against three bacterial and two fungal strains by using the paper disc diffusion method. Results: The methanolic extract exhibited antibacterial activity against E. coli with minimum inhibitory concentration, 0.78 μg/ml, minimum bactericidal concentration of 50 μg/ml, and appreciable antifungal activity with minimum inhibitory concentration of 12.5 μg/ml. Preliminary phytochemical analysis of methanolic extract revealed the presence of antimicrobial compounds such as flavonoids, steroids, and tannins, which may contribute for the antimicrobial action of P. guajava. Conclusion: The extract was found to be bacteriostatic and fungistatic in action.

  4. ANTIMICROBIAL ACTIVITY OF WATER EXTRACTS OF TRIKATU CHURNA AND ITS INDIVIDUAL INGREDIENT

    Directory of Open Access Journals (Sweden)

    P.R. Malvankar* and M. M. Abhyankar

    2012-04-01

    Full Text Available Trikatu churna is one of the traditional poly herbal preparation, formed by mixing equal quantities of three important spicy materials such as Piper longum L. (Piperaceae, Piper nigrum L. (Piperaceae and Zingiber officinale Roscoe (Zingiberaceae. Trikatu is also known as “ Three Bitters”. The trikatu preparation was reported to contain alkaloids, phenols, tannins, flavanoids, steroids, lignin & saponins. The objective of study is to evaluate the antimicrobial activity of trikatu churna & its individual ingredients with their preliminary phytochemical study. The aqueous extracts of trikatu churna & its each ingredient were tested for antimicrobial activity against certain bacterial strains of Escherichia coli, Staphylococcus aureus by in vitro agar well diffusion method and the results are recorded as the zone of inhibition. Trikatu churna was found to possess higher extent of phytoconstituents with promising antimicrobial activity.

  5. The challenges of green nanotechnology

    Directory of Open Access Journals (Sweden)

    Miguel de la Guardia

    2014-03-01

    Full Text Available Nanomaterials have great impacts on life sciences; however,these advanced materials may induce inadvertant consequences.Thus, this editorial will highlight the futuristic challenges in green nanotechnology.

  6. The antimicrobial possibilities of green tea

    Directory of Open Access Journals (Sweden)

    Wanda C Reygaert

    2014-08-01

    Full Text Available Green tea is a popular drink, especially in Asian countries, although its popularity continues to spread across the globe. The health benefits of green tea, derived from the leaves of the Camellia sinensis plant, have been studied for many years. Fairly recently, researchers have begun to look at the possibility of using green tea in antimicrobial therapy, and the potential prevention of infections. The particular properties of catechins found in the tea have shown promise for having antimicrobial effects. There are four main catechins (polyphenols found in green tea: (--epicatechin (EC, (--epicatechin-3-gallate (ECG, (--epigallocatechin (EGC, and (--epigallocatechin-3-gallate (EGCG. Three of these, ECG, EGC, and EGCG have been shown to have antimicrobial effects against a variety of organisms. These catechins have exhibited a variety of antimicrobial mechanisms. The results of studies on the antimicrobial effects of green tea have shown that the potential for preventive and therapeutic purposes is present. Further data collection on studies performed with human consumption during the course of infections, and studies on the occurrence of infections in populations that consume regular amounts of green tea will be necessary to complete the picture of its antimicrobial possibilities.

  7. Biocompatibility and antimicrobial activity of zinc(II doped hydroxyapatite, synthesized by hydrothermal method

    Directory of Open Access Journals (Sweden)

    Kojić Vesna

    2012-01-01

    Full Text Available In order to obtain multifunctional materials with good biocompatibility and antimicrobial effect, hydroxyapatite (HAp doped with Zn2+ was synthesized by hydrothermal method. Powders with different content of zinc ions were synthesized and compared with undoped HAp to investigation of Zn2+ ion influence on the antimicrobial activity of HAp. Analyses of undoped and Zn2+-doped powders before and after thermal treatment at 1200ºC were performed by SEM and XRD. Antimicrobial effects of powders were examined in relation to Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Candida albicans in liquid medium. The results showed that the obtained powders have good antimicrobial activity, but higher antimicrobial activities of powders doped with Zn2+ were observed after annealing at 1200°C. For powders annealed at 1200°C in vitro biocompatibility tests MTT and DET with MRC-5 fibroblast cells in liquid medium were carried out. Based on MTT and DET tests it was shown that powders do not have a significant cytotoxic effect, which was confirmed by SEM analysis of MRC-5 fibroblast cells after theirs in vitro contact with powders. [Projekat Ministarstva nauke Republike Srbije, br. III 45019 and FP7-REGPOT-2009-1 NANOTECH FTM

  8. Polydimethylsiloxane-polymethacrylate block copolymers tethering quaternary ammonium salt groups for antimicrobial coating

    International Nuclear Information System (INIS)

    Highlights: • A series of PDMS-b-QPDMAEMA block copolymers were synthesized via RAFT polymerization. • The composition and morphology of the copolymer films strongly depended on the content of QPDMAEMA. • Migration of QPDMAEMA blocks toward surface was promoted when contacting with water. • Heterogeneous film surfaces with higher N+ content exhibited more obvious antimicrobial activity. - Abstract: Block copolymers PDMS-b-PDMAEMA were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization involving N,N-dimethylaminoethyl methacrylate (DMAEMA) by using poly(dimethylsiloxane) (PDMS) macro-chain transfer agent. And, the tertiary amino groups in PDMAEMA were quaternized with n-octyliodide to provide quaternary ammonium salts (QPDMAEMA). The well-defined copolymers generated composition variation and morphology evolvement on film surfaces, which were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The results indicated that the enrichment of QPDMAEMA brought about lower elemental ratios of Si/N on the film surfaces. The surface morphologies evolved with the variations of QPDMAEMA content, and the variation trend of film roughness was exactly opposite to that of water contact angle hysteresis. With regard to structure-antimicrobial relationships, the copolymer films had more evident antimicrobial activity against Gram-positive, Bacillus subtilis, and the surfaces with heterogeneous morphology and higher N+ content presented better antimicrobial activity. The functionalized copolymers based PDMS and quaternary ammonium salts materials have the potential applications as antimicrobial coatings

  9. Antimicrobial activity of Paenibacillus kribbensis POC 115 against the dermatophyte Trichophyton rubrum.

    Science.gov (United States)

    Cotta, Simone Raposo; da Mota, Fabio Faria; Tupinambá, Gleiser; Ishida, Kelly; Rozental, Sonia; E Silva, Davi Oliveira; da Silva, Antônio Jorge Ribeiro; Bizzo, Humberto Ribeiro; Alviano, Daniela Sales; Alviano, Celuta Sales; Seldin, Lucy

    2012-03-01

    In a search for an antifungal substance with activity against the dermatophyte fungus Trichophyton rubrum, strain POC 115 was chosen among different Paenibacillus strains for its phenotypic and genetic characterization and for preliminary characterization of its antimicrobial substance. Strain POC 115 was identified as belonging to Paenibacillus kribbensis. Physico-chemical characterization of the antimicrobial substance showed that it was not stable during heat and organic solvents treatments, but its activity was preserved at a wide range of pH and after treatment with pronase E, trypsin and DNase I. The crude concentrated supernatant of POC 115 culture was partially purified and the fraction presenting antimicrobial activity was further analyzed by UPLC/Mass Spectrometry. Two peaks were observed at 2.02 (mass 1,207 D) and 2.71 (mass 1,014 D) min in the mass chromatogram. The antimicrobial substance produced by POC 115 was correlated to iturin family compounds based on a set of primers designed for the amplification of PKS operon in the POC 115 genome. As happens with the mode of action of the antibiotics of the iturin group, the AMS produced by POC 115 caused the disruption of cytoplasmic membrane of T. rubrum and the subsequent withdraw of the intracellular material. This is the first report on the production of antimicrobial substances in P. kribbensis, and it may be of great relevance as an alternative or supplementary substance to antifungal drugs currently used against dermatophytes. PMID:22805816

  10. Polydimethylsiloxane-polymethacrylate block copolymers tethering quaternary ammonium salt groups for antimicrobial coating

    Energy Technology Data Exchange (ETDEWEB)

    Qin, Xiaoshuai; Li, Yancai; Zhou, Fang; Ren, Lixia; Zhao, Yunhui, E-mail: zhaoyunhui@tju.edu.cn; Yuan, Xiaoyan

    2015-02-15

    Highlights: • A series of PDMS-b-QPDMAEMA block copolymers were synthesized via RAFT polymerization. • The composition and morphology of the copolymer films strongly depended on the content of QPDMAEMA. • Migration of QPDMAEMA blocks toward surface was promoted when contacting with water. • Heterogeneous film surfaces with higher N{sup +} content exhibited more obvious antimicrobial activity. - Abstract: Block copolymers PDMS-b-PDMAEMA were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization involving N,N-dimethylaminoethyl methacrylate (DMAEMA) by using poly(dimethylsiloxane) (PDMS) macro-chain transfer agent. And, the tertiary amino groups in PDMAEMA were quaternized with n-octyliodide to provide quaternary ammonium salts (QPDMAEMA). The well-defined copolymers generated composition variation and morphology evolvement on film surfaces, which were characterized by X-ray photoelectron spectroscopy, atomic force microscopy, and contact angle measurements. The results indicated that the enrichment of QPDMAEMA brought about lower elemental ratios of Si/N on the film surfaces. The surface morphologies evolved with the variations of QPDMAEMA content, and the variation trend of film roughness was exactly opposite to that of water contact angle hysteresis. With regard to structure-antimicrobial relationships, the copolymer films had more evident antimicrobial activity against Gram-positive, Bacillus subtilis, and the surfaces with heterogeneous morphology and higher N{sup +} content presented better antimicrobial activity. The functionalized copolymers based PDMS and quaternary ammonium salts materials have the potential applications as antimicrobial coatings.

  11. Physical, Antioxidant and Antimicrobial Characteristics of Carboxymethyl Cellulose Edible Film Cooperated with Clove Essential Oil

    Directory of Open Access Journals (Sweden)

    Ramin Khaksar

    2014-08-01

    Full Text Available Background: Carboxymethyl cellulose (CMC is one of the most common cellulose derivatives. It has many applications such as edible films and coating. Antioxidant and antimicrobial of essential oils and their direct or indirect usage in foods have been investigated. This study focuses on the physical, chemical, antioxidant and antimicrobial characteristics of CMC edible film incorporated with clove essential oils (CEO. Materials and Methods: In this experimental study, CMC edible films with or without clove essential oil were prepared by casting method and many characteristics such as thickness, water vapor permeability (WVP, tensile strength, elongation at break, optical characteristics, microstructure, antimicrobial and antioxidant properties of the films were assessed. Results: Tensile strength values were higher when compared with those of control film (pure CMC film, especially in 1% EO concentration. Elongation at break value in 1% EO was higher than control film, but by increasing of EO portion, it decreased. Antioxidant properties and total phenolic compounds as expected increased in higher concentration of EO. Antimicrobial properties of the films showed that films incorporated with EO are effective against selected pathogen bacteria, especially in the higher concentration of EO. Some variations in the structure of various films were shown by scanning electron microscopy (SEM. Additions of EO into CMC film disrupted condense structure of film and produced a heterogeneous structure. Conclusion: As antimicrobial and antioxidant properties of CEO retain when it used in CMC edible film, it could be beneficial in food packaging to retard of deterioration.

  12. Zinc Pyrithione: A Topical Antimicrobial With Complex Pharmaceutics.

    Science.gov (United States)

    Schwartz, James R

    2016-02-01

    Zinc pyrithione (ZPT) is an active material that has been used for over 50 years to effectively treat dandruff and seborrheic dermatitis (D/SD). It has become the most common material for that purpose, its use has expanded to include other skin benefits such as skin hygiene. However, there is much about ZPT that is unappreciated. It is a rationally developed molecule that was modeled after the naturally occurring antimicrobial aspergillic acid. The molecular basis for its antifungal activity has been elucidated. The efficacy of ZPT originates from two attributes. First, it has a very broad antimicrobial spectrum of activity, including fungi, gram-positive and -negative bacteria. Second, the material has very low solubility, resulting in formulation and delivery as a particulate material, which has distinct performance advantages. The particles are deposited and retained on the target skin surfaces even when delivered from rinse-off products. These particles slowly release molecularly active material to interact with the surface fungal and bacteria cells to control their population, functioning as slow-release reservoirs to provide extended and persistent benefits. This particulate nature, though, results in complex pharmaceutics to realize the full efficacy benefits; it is common to see products with the same ZPT level having widely varying levels of clinical performance. Several product matrix-determined factors directly impact resultant benefits: ZPT must be retained on the skin surface achieving uniform spatial distribution laterally as well as within hair follicles (especially on scalp); ZPT must be maintained as a physically stable dispersion in product; ZPT must be maintained in a chemically active form as there are many chemical reactions that can occur that can harm ZPT bioactivity. The benefits achievable by employing ZPT require significant pharmaceutics expertise to realize the full benefits of this active material. J Drugs Dermatol. 2016

  13. Understanding the mechanisms and drivers of antimicrobial resistance.

    Science.gov (United States)

    Holmes, Alison H; Moore, Luke S P; Sundsfjord, Arnfinn; Steinbakk, Martin; Regmi, Sadie; Karkey, Abhilasha; Guerin, Philippe J; Piddock, Laura J V

    2016-01-01

    To combat the threat to human health and biosecurity from antimicrobial resistance, an understanding of its mechanisms and drivers is needed. Emergence of antimicrobial resistance in microorganisms is a natural phenomenon, yet antimicrobial resistance selection has been driven by antimicrobial exposure in health care, agriculture, and the environment. Onward transmission is affected by standards of infection control, sanitation, access to clean water, access to assured quality antimicrobials and diagnostics, travel, and migration. Strategies to reduce antimicrobial resistance by removing antimicrobial selective pressure alone rely upon resistance imparting a fitness cost, an effect not always apparent. Minimising resistance should therefore be considered comprehensively, by resistance mechanism, microorganism, antimicrobial drug, host, and context; parallel to new drug discovery, broad ranging, multidisciplinary research is needed across these five levels, interlinked across the health-care, agriculture, and environment sectors. Intelligent, integrated approaches, mindful of potential unintended results, are needed to ensure sustained, worldwide access to effective antimicrobials. PMID:26603922

  14. [The role of antimicrobial stewardship programs in the control of bacterial resistance].

    Science.gov (United States)

    Pasquau, J; Sadyrbaeva, S; De Jesús, S E; Hidalgo-Tenorio, C

    2016-09-01

    In order to improve infection prognosis and reduce the existing microbial resistance problem (a challenge similar to that of climate change), a higher implication of the Administration, an increased level of social awareness and the development of specific corporate networks, including the pharmaceutical industry, is needed. However, we must first consolidate Antimicrobial Stewardship Programmes with experts who seek to improve antibiotic therapy effectivity in severe infections and to reduce global antibiotic exposure. PMID:27608314

  15. Quorum sensing inhibitory drugs as next generation antimicrobials: worth the effort?

    DEFF Research Database (Denmark)

    Bjarnsholt, Thomas; Givskov, M.

    2008-01-01

    , elderly, immunocompromised, and hospitalized patients are susceptible to infections caused by bacteria such as Pseudomonas aeruginosa, Staphylococcus aureus, and Staphylococcus epidermidis. These bacteria form chronic, biofilm-based infections, which are challenging because bacterial cells living as...... biofilms are more tolerant to antibiotics than their planktonic counterparts. Therefore, research should identify new antimicrobial agents and their corresponding targets to decrease the biofilm-forming capability or persistence of the infectious bacteria. Here, we review one such drug target: bacterial...

  16. Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

    OpenAIRE

    Marcela Radaelli; Bárbara Parraga da Silva; Luciana Weidlich; Lucélia Hoehne; Adriana Flach; Luiz Antonio Mendonça Alves da Costa; Eduardo Miranda Ethur

    2016-01-01

    Abstract Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piper...

  17. Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

    OpenAIRE

    Radaelli, Marcela; da Silva, Bárbara Parraga; Weidlich, Luciana; Hoehne, Lucélia; FLACH, ADRIANA; da Costa, Luiz Antonio Mendonça Alves; Ethur, Eduardo Miranda

    2016-01-01

    Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. va...

  18. Antimicrobial activity and phytochemical analysis of selected Indian folk medicinal plants

    OpenAIRE

    Mohamed Sham Shihabudeen. H; Hansi Priscilla. D; Kavitha Thirumurugan

    2010-01-01

    The success of chemotherapy lies in the continuous search for new drugs to counter the challenge posed by resistant strains. Methanol extracts of six plant species traditionally used in Indian folklore medicine for the treatment of various bacterial and fungal infections were investigated for in vitro antimicrobial activity against pathogens namely Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans and Aspergill...

  19. Antimicrobial use and infections in Finnish long-term care facilities

    OpenAIRE

    Rummukainen, Maija-Liisa

    2013-01-01

    Background and aims. The rapidly growing ageing population results in a demand for new types of housing that may face the same challenges as nursing homes (NHs) do today. Elderly persons are at particular risk for healthcare-associated infections, since few long-term care facilities (LTCFs) have in-house expertise in infection control or in infectious diseases. This may lead to inappropriate prescription of antimicrobials and promote development of multidrug-resistant bacteria. The movement o...

  20. Mechanical joining and adhesive bonding. Joining processes with new challenges to materials testing; Umformen und Kleben. Fuegeverfahren mit neuen Herausforderungen fuer die Materialpruefung

    Energy Technology Data Exchange (ETDEWEB)

    Meschut, G. [Volkswagen AG, Wolfsburg (Germany)

    2002-07-01

    This contribution highlights new material combinations in the automotive industry to demonstrate the mutual dependence of joining processes and their implications for the geometric shaping of fasteners in the combined shaping and adhesive bonding joining process. The mechanical properties of joints produced by combined and elementary methods are compared taking into consideration quasi static, oscillating and impact-type loads, and ageing characteristics. The results demonstrate that the combination of mechanical and adhesive bonding methods produces joints of high technological quality which can be implemented in optimised light-weight construction. General information is provided on the use of low-heat hybrid joining technology for project planning of this type of connections in industrial practice. (orig.)