WorldWideScience

Sample records for microbial barrier properties

  1. Comfort and microbial barrier properties of garments worn next to the skin

    Science.gov (United States)

    Kopitar, D.; Rogina-Car, B.; Skenderi, Z.

    2017-10-01

    Compared with viscose fibre, modal fibre is characterized by some advantageous properties such as higher dry and wet tenacities, higher wet modulus, lower water retention capacity and lower level of swelling. Impact of different knitted fabric structure made of cotton and 97 % CMD/3 % EL fibres on thermo-physiological comfort and microbial barrier properties were investigated. All knitted fabrics have very good physiological properties. The microbial barrier permeability of knitted fabric after extreme contamination with bacterial spores in dry state showed that double jersey offered more effective microbial barrier than the single jersey knitted fabrics respectively the greater thickness of double jersey knitted fabric provide more difficult barrier to bacterial spores to pass. In wet state all knitted fabrics have more effective microbial barrier which could be explained by cellulose fibres swelling. In wet state 97 % CMD/3 % EL single jersey knitted fabric have more effective microbial barrier then cotton double and single jersey knitted fabrics.

  2. Bentonite. Geotechnical barrier and source for microbial life

    Energy Technology Data Exchange (ETDEWEB)

    Matschiavelli, Nicole; Kluge, Sindy; Cherkouk, Andrea [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). HZDR Young Investigator Group; Steglich, Jennifer

    2017-06-01

    Due to their properties, namely a high swelling capacity and a low hydraulic conductivity, Bentonites fulfil as geotechnical barrier a sealing and buffering function in the nuclear waste repository. Depending on the mineral composition Bentonites contain many suitable electron-donors and -acceptors, enabling potential microbial life. For the potential repository of highly radioactive waste the microbial mediated transformation of Bentonite could influence its properties as a barrier material. Microcosms were set up containing Bentonite and anaerobic synthetic Opalinus-clay-pore water solution under an N{sub 2}/CO{sub 2}-atmosphere to elucidate the microbial potential within selected Bentonites. Substrates like acetate and lactate were supplemented to stimulate potential microbial activity. First results show that bentonites represent a source for microbial life, demonstrated by the consumption of lactate and the formation of pyruvate. Furthermore, microbial iron-reduction was determined, which plays a crucial role in Betonite-transformation.

  3. Bentonite. Geotechnical barrier and source for microbial life

    International Nuclear Information System (INIS)

    Matschiavelli, Nicole; Kluge, Sindy; Cherkouk, Andrea; Steglich, Jennifer

    2017-01-01

    Due to their properties, namely a high swelling capacity and a low hydraulic conductivity, Bentonites fulfil as geotechnical barrier a sealing and buffering function in the nuclear waste repository. Depending on the mineral composition Bentonites contain many suitable electron-donors and -acceptors, enabling potential microbial life. For the potential repository of highly radioactive waste the microbial mediated transformation of Bentonite could influence its properties as a barrier material. Microcosms were set up containing Bentonite and anaerobic synthetic Opalinus-clay-pore water solution under an N_2/CO_2-atmosphere to elucidate the microbial potential within selected Bentonites. Substrates like acetate and lactate were supplemented to stimulate potential microbial activity. First results show that bentonites represent a source for microbial life, demonstrated by the consumption of lactate and the formation of pyruvate. Furthermore, microbial iron-reduction was determined, which plays a crucial role in Betonite-transformation.

  4. Measuring solvent barrier properties of paper

    International Nuclear Information System (INIS)

    Bollström, Roger; Saarinen, Jarkko J; Toivakka, Martti; Räty, Jukka

    2012-01-01

    New methods for measuring barrier properties against solvents, acids and bases on dispersion coated paper were developed and investigated. Usability, reliability and repeatability were compared both between the new methods and with the standardized method for measuring barrier properties against water vapor. Barrier properties could be measured with all methods and the results obtained by the different methods were in correlation with each other. A qualitative method based on a trace color provided an indicative result, whereas further developed methods also took into account the durability. The effective barrier lifetime could be measured by measuring the conductivity through the substrate as a function of time, or by utilizing a glass prism where the change in refractive index caused by penetrated liquid was monitored, also as a function of time. Barrier properties against water and humidity were also measured and were found not to be predictors for barrier properties against either solvents, or acids or bases, which supports the need to develop new methods

  5. Thermal barriers constrain microbial elevational range size via climate variability.

    Science.gov (United States)

    Wang, Jianjun; Soininen, Janne

    2017-08-01

    Range size is invariably limited and understanding range size variation is an important objective in ecology. However, microbial range size across geographical gradients remains understudied, especially on mountainsides. Here, the patterns of range size of stream microbes (i.e., bacteria and diatoms) and macroorganisms (i.e., macroinvertebrates) along elevational gradients in Asia and Europe were examined. In bacteria, elevational range size showed non-significant phylogenetic signals. In all taxa, there was a positive relationship between niche breadth and species elevational range size, driven by local environmental and climatic variables. No taxa followed the elevational Rapoport's rule. Climate variability explained the most variation in microbial mean elevational range size, whereas local environmental variables were more important for macroinvertebrates. Seasonal and annual climate variation showed negative effects, while daily climate variation had positive effects on community mean elevational range size for all taxa. The negative correlation between range size and species richness suggests that understanding the drivers of range is key for revealing the processes underlying diversity. The results advance the understanding of microbial species thermal barriers by revealing the importance of seasonal and diurnal climate variation, and highlight that aquatic and terrestrial biota may differ in their response to short- and long-term climate variability. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Functional barriers: Properties and evaluation

    NARCIS (Netherlands)

    Feigenbaum, A.; Dole, P.; Aucejo, S.; Dainelli, D.; Cruz Garcia, C. de la; Hankemeier, T.; N'Gono, Y.; Papaspyrides, C.D.; Paseiro, P.; Pastorelli, S.; Pavlidou, S.; Pennarun, P.Y.; Saillard, P.; Vidal, L.; Vitrac, O.; Voulzatis, Y.

    2005-01-01

    Functional barriers are multilayer structures deemed to prevent migration of some chemicals released by food-contact materials into food. In the area of plastics packaging, different migration behaviours of mono- and multilayer structures are assessed in terms of lag time and of their influence of

  7. Gluconic Acid: Properties, Applications and Microbial Production

    Directory of Open Access Journals (Sweden)

    Sumitra Ramachandran

    2006-01-01

    Full Text Available Gluconic acid is a mild organic acid derived from glucose by a simple oxidation reaction. The reaction is facilitated by the enzyme glucose oxidase (fungi and glucose dehydrogenase (bacteria such as Gluconobacter. Microbial production of gluconic acid is the preferred method and it dates back to several decades. The most studied and widely used fermentation process involves the fungus Aspergillus niger. Gluconic acid and its derivatives, the principal being sodium gluconate, have wide applications in food and pharmaceutical industry. This article gives a review of microbial gluconic acid production, its properties and applications.

  8. Investigating the impact of microbial interactions with geologic media on geophysical properties

    Science.gov (United States)

    Davis, Caroline Ann

    The goals of this study were to investigate the effect of: (1) microbial metabolic byproducts, microbial growth, and biofilm formation on the low frequency electrical properties of porous media, (2) biofilm formation on acoustic wave properties, and (3) the natural electrical (self-potential) signatures associated with an in-situ biological permeable reactive barrier (PRB). The results suggest: (1) increases in electrolytic conductivity are consistent with increased concentrations of organic acids and biosurfactants; (2) mineral weathering promoted by organic acids causes increases in electrolytic conductivity, concomitant with increases in major cation concentrations; (3) interfacial conductivity generally parallels microbial cell concentrations and biofilm formation; (4) variations in microbial growth and biofilms causes spatiotemporal heterogeneity in the elastic properties of porous media; (5) SP signatures associated with the injection of groundwater into an in-situ biological PRB are dominated by diffusion potentials induced by the injections. The results suggest that electrolytic conductivity may be useful as an indicator of metabolism, while interfacial conductivity may be used as proxy indicator for microbial growth and biofilm formation in porous media. In addition, acoustic measurements may provide diagnostic spatiotemporal data for the validation of bioclogging models/simulations. Collectively, this study provides further evidence that geophysical measurements are sensitive to microbial-induced changes to geologic media, and may be useful for the detection and monitoring of subsurface microbial growth, activity, and distribution such as in microbial enhanced oil recovery, assessing biofilm barriers used for contaminant remediation, or as sealants for reservoirs in CO2 sequestration studies.

  9. Characterization of Mechanical Properties of Microbial Biofilms

    Science.gov (United States)

    Callison, Elizabeth; Gose, James; Perlin, Marc; Ceccio, Steven

    2017-11-01

    The physical properties of microbial biofilms grown subject to shear flows determine the form and mechanical characteristics of the biofilm structure, and consequently, the turbulent interactions over and through the biofilm. These biofilms - sometimes referred to as slime - are comprised of microbial cells and extracellular polymeric substance (EPS) matrices that surround the multicellular communities. Some of the EPSs take the form of streamers that tend to oscillate in flows, causing increased turbulent mixing and drag. As the presence of EPS governs the compliance and overall stability of the filamentous streamers, investigation of the mechanical properties of biofilms may also inform efforts to understand hydrodynamic performance of fouled systems. In this study, a mixture of four diatom genera was grown under turbulent shear flow on test panels. The mechanical properties and hydrodynamic performance of the biofilm were investigated using rheology and turbulent flow studies in the Skin-Friction Flow Facility at the University of Michigan. The diatoms in the mixture of algae were identified, and the elastic and viscous moduli were determined from small-amplitude oscillations, while a creep test was used to evaluate the biofilm compliance.

  10. Microbial lipases: Production, properties and biotechnological applications

    Directory of Open Access Journals (Sweden)

    Josana Maria Messias

    2011-09-01

    Full Text Available Lipases belong to the group of hydrolases that catalyze the hydrolysis of triacylglycerol lipids to free fatty acids and glycerol. They have significant potential biotechnological applications in catalyzing organic synthesis reactions in non-aqueous solvents using simplified procedures resulting in conversions of high yields. Lipase production has conventionally been performed by submerged fermentation; however, solid-state fermentation processes have been prominent when residues are used as substrates because they serve as low-cost nutrient sources. Microbial lipases can be used as additives in foods to modify and enhance organoleptic properties, as well as in detergents to hydrolyse fats in the treatment of oily effluents, and also have value for pharmaceutical, cosmetic, agrochemical, and oil chemical industries. More recently, they are used in transesterification reactions to convert plant seed oils into biodiesel. The objective of this work was to review the published literature on the production, properties and applications of microbial lipases, and its biotechnological role in producing biodiesel.

  11. Microbial diversity and structure are drivers of the biological barrier effect against Listeria monocytogenes in soil.

    Science.gov (United States)

    Vivant, Anne-Laure; Garmyn, Dominique; Maron, Pierre-Alain; Nowak, Virginie; Piveteau, Pascal

    2013-01-01

    Understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. We investigated the relationship between soil microbial diversity and the barrier effect against Listeria monocytogenes invasion. By using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on L. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundance in soil microcosms. We demonstrated that highly diverse soil microbial communities act as a biological barrier against L. monocytogenes invasion and that phylogenetic composition of the community also has to be considered. This suggests that erosion of diversity may have damaging effects regarding circulation of pathogenic microorganisms in the environment.

  12. Technical considerations for the implementation of subsurface microbial barriers for restoration of groundwater at UMTRA sites

    International Nuclear Information System (INIS)

    Tucker, M.D.

    1996-01-01

    The Uranium Mill Tailings Remediation Action (UMTRA) Program is responsible for the assessment and remedial action at the 24 former uranium mill tailings sites located in the United States. The surface remediation phase, which has primarily focused on containment and stabilization of the abandoned uranium mill tailings piles, is nearing completion. Attention has now turned to the groundwater restoration phase. One alternative under consideration for groundwater restoration at UMTRA sites is the use of in-situ permeable reactive subsurface barriers. In this type of a system, contaminated groundwater will be allowed to flow naturally through a barrier filled with material which will remove hazardous constituents from the water by physical, chemical or microbial processes while allowing passage of the pore water. The subject of this report is a reactive barrier which would remove uranium and other contaminants of concern from groundwater by microbial action (i.e., a microbial barrier). The purpose of this report is to assess the current state of this technology and to determine issues that must be addressed in order to use this technology at UMTRA sites. The report focuses on six contaminants of concern at UMTRA sites including uranium, arsenic, selenium, molybdenum, cadmium and chromium. In the first section of this report, the fundamental chemical and biological processes that must occur in a microbial barrier to control the migration of contaminants are described. The second section contains a literature review of research which has been conducted on the use of microorganisms to immobilize heavy metals. The third section addresses areas which need further development before a microbial barrier can be implemented at an UMTRA site

  13. Technical considerations for the implementation of subsurface microbial barriers for restoration of groundwater at UMTRA sites

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, M.D.

    1996-01-01

    The Uranium Mill Tailings Remediation Action (UMTRA) Program is responsible for the assessment and remedial action at the 24 former uranium mill tailings sites located in the United States. The surface remediation phase, which has primarily focused on containment and stabilization of the abandoned uranium mill tailings piles, is nearing completion. Attention has now turned to the groundwater restoration phase. One alternative under consideration for groundwater restoration at UMTRA sites is the use of in-situ permeable reactive subsurface barriers. In this type of a system, contaminated groundwater will be allowed to flow naturally through a barrier filled with material which will remove hazardous constituents from the water by physical, chemical or microbial processes while allowing passage of the pore water. The subject of this report is a reactive barrier which would remove uranium and other contaminants of concern from groundwater by microbial action (i.e., a microbial barrier). The purpose of this report is to assess the current state of this technology and to determine issues that must be addressed in order to use this technology at UMTRA sites. The report focuses on six contaminants of concern at UMTRA sites including uranium, arsenic, selenium, molybdenum, cadmium and chromium. In the first section of this report, the fundamental chemical and biological processes that must occur in a microbial barrier to control the migration of contaminants are described. The second section contains a literature review of research which has been conducted on the use of microorganisms to immobilize heavy metals. The third section addresses areas which need further development before a microbial barrier can be implemented at an UMTRA site.

  14. Heavy metal levels, physicochemical properties and microbial ...

    African Journals Online (AJOL)

    Journal of Applied Sciences and Environmental Management ... out to assess the microbial, physicochemical and heavy metal characteristics of soil samples from five different waste collection sites within the University of Benin, Benin City and evaluated using standard analytical and classical microbiological methods.

  15. Barrier properties of cultured retinal pigment epithelium.

    Science.gov (United States)

    Rizzolo, Lawrence J

    2014-09-01

    The principal function of an epithelium is to form a dynamic barrier that regulates movement between body compartments. Each epithelium is specialized with barrier functions that are specific for the tissues it serves. The apical surface commonly faces a lumen, but the retinal pigment epithelium (RPE) appears to be unique by a facing solid tissue, the sensory retina. Nonetheless, there exists a thin (subretinal) space that can become fluid filled during pathology. RPE separates the subretinal space from the blood supply of the outer retina, thereby forming the outer blood-retinal barrier. The intricate interaction between the RPE and sensory retina presents challenges for learning how accurately culture models reflect native behavior. The challenge is heightened by findings that detail the variation of RPE barrier proteins both among species and at different stages of the life cycle. Among the striking differences is the expression of claudin family members. Claudins are the tight junction proteins that regulate ion diffusion across the spaces that lie between the cells of a monolayer. Claudin expression by RPE varies with species and life-stage, which implies functional differences among commonly used animal models. Investigators have turned to transcriptomics to supplement functional studies when comparing native and cultured tissue. The most detailed studies of the outer blood-retinal barrier have focused on human RPE with transcriptome and functional studies reported for human fetal, adult, and stem-cell derived RPE. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Effect of the barrier properties on the surface part of the barrier discharge

    International Nuclear Information System (INIS)

    Sokolova, M.V.; Zhukov, S.V.

    1998-01-01

    The effect of barrier characteristics on the discharge processes in a barrier discharge was investigated, main attention being paid to the amount and distribution of the charge left on the barrier surface by the volume discharge in the main air gap. The measurements show that the main part of the gap charge is due to the volume part of the discharge. The measured values of the surface charge significantly increase with the voltage applied and with the length of the gas gap, while the dimensions of the charge spot and the distribution of charge density are determined by the barrier properties. (J.U.)

  17. Tight junction proteins contribute to barrier properties in human pleura.

    Science.gov (United States)

    Markov, Alexander G; Voronkova, Maria A; Volgin, George N; Yablonsky, Piotr K; Fromm, Michael; Amasheh, Salah

    2011-03-15

    The permeability of pleural mesothelium helps to control the volume and composition of the liquid lubricating pleural surfaces. Information on pleural barrier function in health and disease, however, is scarce. Tissue specimens of human pleura were mounted in Ussing chambers for measurement of transmesothelial resistance. Expression of tight junction (TJ) proteins was studied by Western blots and immune fluorescence confocal microscopy. Both visceral and parietal pleura showed barrier properties represented by transmesothelial resistance. Occludin, claudin-1, -3, -5, and -7, were detected in visceral pleura. In parietal pleura, the same TJ proteins were detected, except claudin-7. In tissues from patients with pleural inflammation these tightening claudins were decreased and in visceral pleura claudin-2, a paracellular channel former, became apparent. We report that barrier function in human pleura coincides with expression of claudins known to be key determinants of epithelial barrier properties. In inflamed tissue, claudin expression indicates a reduced barrier function. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Antivirulence Properties of Probiotics in Combating Microbial Pathogenesis.

    Science.gov (United States)

    Surendran Nair, M; Amalaradjou, M A; Venkitanarayanan, K

    2017-01-01

    Probiotics are nonpathogenic microorganisms that confer a health benefit on the host when administered in adequate amounts. Ample evidence is documented to support the potential application of probiotics for the prevention and treatment of infections. Health benefits of probiotics include prevention of diarrhea, including antibiotic-associated diarrhea and traveler's diarrhea, atopic eczema, dental carries, colorectal cancers, and treatment of inflammatory bowel disease. The cumulative body of scientific evidence that demonstrates the beneficial effects of probiotics on health and disease prevention has made probiotics increasingly important as a part of human nutrition and led to a surge in the demand for probiotics in clinical applications and as functional foods. The ability of probiotics to promote health is attributed to the various beneficial effects exerted by these microorganisms on the host. These include lactose metabolism and food digestion, production of antimicrobial peptides and control of enteric infections, anticarcinogenic properties, immunologic enhancement, enhancement of short-chain fatty acid production, antiatherogenic and cholesterol-lowering attributes, regulatory role in allergy, protection against vaginal or urinary tract infections, increased nutritional value, maintenance of epithelial integrity and barrier, stimulation of repair mechanism in cells, and maintenance and reestablishment of well-balanced indigenous intestinal and respiratory microbial communities. Most of these attributes primarily focus on the effect of probiotic supplementation on the host. Hence, in most cases, it can be concluded that the ability of a probiotic to protect the host from infection is an indirect result of promoting overall health and well-being. However, probiotics also exert a direct effect on invading microorganisms. The direct modes of action resulting in the elimination of pathogens include inhibition of pathogen replication by producing

  19. Physicochemical, microbial and sensory properties of milk, butter ...

    African Journals Online (AJOL)

    A study on the physicochemical, microbial load and sensory properties of milk, butter with or without garlic was carried out using fresh milk from white Fulani cow for eight weeks of the lactation. The milk used was milked manually by the Fulanis early in the morning. Fat content was highest in milk (4.13±0.16) and least in ...

  20. Biochemical properties and microbial analysis of honey from North ...

    African Journals Online (AJOL)

    In the present study, physicochemical properties (pH, ash, commercial glucose, starch, reducing sugars and moisture) and microbial (yeast and enterobacterial) contaminations of 263 honey samples from North-western regions of Iran were evaluated in a 2 year period in different seasons of 2010 and 2011. Levels of ...

  1. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions

    Science.gov (United States)

    Gentil, Dana; del Campo, Valeria; Henrique Rodrigues da Cunha, Thiago; Henríquez, Ricardo; Garín, Carolina; Ramírez, Cristian; Flores, Marcos; Seeger, Michael

    2017-01-01

    In this work we present a study on the performance of CVD (chemical vapor deposition) graphene coatings grown and transferred on Ni as protection barriers under two scenarios that lead to unwanted metal ion release, microbial corrosion and allergy test conditions. These phenomena have a strong impact in different fields considering nickel (or its alloys) is one of the most widely used metals in industrial and consumer products. Microbial corrosion costs represent fractions of national gross product in different developed countries, whereas Ni allergy is one of the most prevalent allergic conditions in the western world, affecting around 10% of the population. We found that grown graphene coatings act as a protective membrane in biological environments that decreases microbial corrosion of Ni and reduces release of Ni2+ ions (source of Ni allergic contact hypersensitivity) when in contact with sweat. This performance seems not to be connected to the strong orbital hybridization that Ni and graphene interface present, indicating electron transfer might not be playing a main role in the robust response of this nanostructured system. The observed protection from biological environment can be understood in terms of graphene impermeability to transfer Ni2+ ions, which is enhanced for few layers of graphene grown on Ni. We expect our work will provide a new route for application of graphene as a protection coating for metals in biological environments, where current strategies have shown short-term efficiency and have raised health concerns. PMID:29292763

  2. HIV enteropathy and aging: gastrointestinal immunity, mucosal epithelial barrier, and microbial translocation.

    Science.gov (United States)

    Wang, Hongyin; Kotler, Donald P

    2014-07-01

    Despite decreases in morbidity and mortality as a result of antiretroviral therapy, gastrointestinal dysfunction remains common in HIV infection. Treated patients are at risk for complications of 'premature' aging, such as cardiovascular disease, osteopenia, neurocognitive decline, malignancies, and frailty. This review summarizes recent observations in this field. Mucosal CD4 lymphocytes, especially Th17 cells, are depleted in acute HIV and simian immune deficiency virus (SIV) infections, although other cell types also are affected. Reconstitution during therapy often is incomplete, especially in mucosa. Mucosal barrier function is affected by both HIV infection and aging and includes paracellular transport via tight junctions and uptake through areas of apoptosis; other factors may affect systemic antigen exposure. The resultant microbial translocation is associated with systemic immune activation in HIV and SIV infections. There is evidence of immune activation and microbial translocation in the elderly. The immune phenotypes of immunosenescence in HIV infection and aging appear similar. There are several targets for intervention; blockage of residual mucosal virus replication, preventing antigen uptake, modulating the microbiome, improving T cell recovery, combining therapies aimed at mucosal integrity, augmenting mucosal immunity, and managing traditional risk factors for premature aging in the general population. Aging may interact with HIV enteropathy to enhance microbial translocation and immune activation.

  3. The Many Faces of Graphene as Protection Barrier. Performance under Microbial Corrosion and Ni Allergy Conditions

    Directory of Open Access Journals (Sweden)

    Carolina Parra

    2017-12-01

    Full Text Available In this work we present a study on the performance of CVD (chemical vapor deposition graphene coatings grown and transferred on Ni as protection barriers under two scenarios that lead to unwanted metal ion release, microbial corrosion and allergy test conditions. These phenomena have a strong impact in different fields considering nickel (or its alloys is one of the most widely used metals in industrial and consumer products. Microbial corrosion costs represent fractions of national gross product in different developed countries, whereas Ni allergy is one of the most prevalent allergic conditions in the western world, affecting around 10% of the population. We found that grown graphene coatings act as a protective membrane in biological environments that decreases microbial corrosion of Ni and reduces release of Ni2+ ions (source of Ni allergic contact hypersensitivity when in contact with sweat. This performance seems not to be connected to the strong orbital hybridization that Ni and graphene interface present, indicating electron transfer might not be playing a main role in the robust response of this nanostructured system. The observed protection from biological environment can be understood in terms of graphene impermeability to transfer Ni2+ ions, which is enhanced for few layers of graphene grown on Ni. We expect our work will provide a new route for application of graphene as a protection coating for metals in biological environments, where current strategies have shown short-term efficiency and have raised health concerns.

  4. Fingolimod promotes blood-nerve barrier properties in vitro.

    Science.gov (United States)

    Nishihara, Hideaki; Maeda, Toshihiko; Sano, Yasuteru; Ueno, Maho; Okamoto, Nana; Takeshita, Yukio; Shimizu, Fumitaka; Koga, Michiaki; Kanda, Takashi

    2018-04-01

    The main effect of fingolimod is thought to be functional antagonism of lymphocytic S1P1 receptors and the prevention of lymphocyte egress from lymphoid tissues, thereby reducing lymphocyte infiltration into the nervous system. However, a growing number of reports suggest that fingolimod also has a direct effect on several cell types in the nervous system. Although we previously reported that fingolimod enhances blood-brain barrier (BBB) functions, there have been no investigations regarding the blood-nerve barrier (BNB). In this study, we examine how fingolimod affects the BNB. An immortalized human peripheral nerve microvascular endothelial cell line (HPnMEC) was used to evaluate BNB barrier properties. We examined tight junction proteins and barrier functions of HPnMECs in conditioned medium with or without fingolimod-phosphate and blood sera from patients with typical chronic inflammatory demyelinating polyneuropathy (CIDP). Incubation with fingolimod-phosphate increased levels of claudin-5 mRNA and protein as well as TEER values in HPnMECs. Conversely, typical CIDP sera decreased claudin-5 mRNA/protein levels and TEER values in HPnMECs; however, pretreatment with fingolimod-phosphate inhibited the effects of the typical CIDP sera. Fingolimod-phosphate directly modifies the BNB and enhances barrier properties. This mechanism may be a viable therapeutic target for CIDP, and fingolimod may be useful in patients with typical CIDP who have severe barrier disruption.

  5. Noninvasive evaluation of the barrier properties of the skin

    Directory of Open Access Journals (Sweden)

    Utz S.R.

    2014-09-01

    Full Text Available Skin as an organ of protection covers the body and accomplishes multiple defensive functions. The intact skin represents a barrier to the uncontrolled loss of water, proteins, and plasma components from the organism. Due to its complex structure, the epidermal barrier with its major component, stratum corneum, is the rate-limiting unit for the penetration of exogenous substances through the skin. The epidermal barrier is not a static structure. The permeability barrier status can be modified by different external and internal factors such as climate, physical stressors, and a number of skin and systemic diseases. Today, different non-invasive approaches are used to monitor the skin barrier physical properties in vivo. The quantification of parameters such as transepidermal water loss, stratum corneum hydration, and skin surface acidity is essential for the integral evaluation of the epidermal barrier status. This paper will allow the readership to get acquainted with the non-invasive, in vivo methods for the investigation of the skin barrier.

  6. Impedance-based cell monitoring: barrier properties and beyond

    Directory of Open Access Journals (Sweden)

    Benson Kathrin

    2013-01-01

    Full Text Available Abstract In multicellular organisms epithelial and endothelial cells form selective permeable interfaces between tissue compartments of different chemical compositions. Tight junctions which connect adjacent cells, control the passage of molecules across the barrier and, in addition, facilitate active transport processes. The cellular barriers are not static but can be deliberately modulated by exposure to specific external stimuli. In vitro models representing the essential absorption barriers of the body are nowadays available, thus allowing investigation of the parameters that control permeability as well as transport processes across those barriers. Independent of the origin of the barrier forming cells, techniques are needed to quantify their barrier integrity. One simple assay is to measure the permeability for given hydrophilic substrates possessing different molecular weights like sucrose or dextrans. However, this technique is time-consuming and labor-intensive. Moreover, radioactive or fluorescently-labeled substrates are needed to allow easy analytical detection. Finally, if transport processes are investigated, the standard permeant may interfere with the transport process under investigation or might even alter the barrier integrity by itself. Thus, independent, non-invasive techniques are needed to quantify the barrier integrity continuously during the experiment. Such techniques are available and are mainly based on the measurement of the transendothelial or transepithelial electrical resistance (TEER of barrier forming cells grown on porous membranes. Simple devices using two sets of electrodes (so-called Voltohmeters are widely used. In addition, an easy-to-use physical technique called impedance spectroscopy allows the continuous analysis of both the TEER and the electrical capacitance giving additional information about the barrier properties of cells grown on permeable membranes. This technique is useful as a quality control

  7. Improvement of barrier properties of rotomolded PE containers with nanoclay

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidi, Shadi; Sundararaj, Uttandaraman, E-mail: u.sundararaj@ucalgary.ca [Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, Alberta, T2N 1N4 (Canada)

    2015-05-22

    Polyethylene (PE) is widely used to make bulk containers in rotational molding process. The challenge in this study is to improve permeation resistance of PE to hydrocarbon solvents and gases. Adding organomodified clay improves the thermal, barrier and mechanical properties of PE. In fact, clay layers create a tortuous path against the permeant, yielding better barrier properties. Due to the non-polar hydrophobic nature of PE and polar hydrophilic structure of clay minerals, the compatibilizer plays a crucial role to enhance the dispersion level of clay in the matrix. In this study High Density Polyethylene (HDPE) and Linear Low Density Polyethylene (LLDPE) layered silicate nanocomposite were melt-compounded with two concentrations of organomodified clay (2 and 4 wt. %). The interaction between nanoclay, compatibilizer and rotomolding grade of PE were examined by using X-ray diffraction, transmission electron microscopy (TEM) and rheology test. Rheology was used to determine the performance of our material at low shear processing condition.

  8. Contribution on the study of microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers

    International Nuclear Information System (INIS)

    Spor, H.

    1994-05-01

    The aim of this work is to study the different interactions mechanisms between microorganisms and radioelements in conditions similar to those of a radioactive waste disposal site and to determine all the mechanisms due to microbial effects on the leaching of radionuclides embedded in nuclear waste engineered barriers. In this work are presented the different following points: - a bibliographic study on the microorganisms-radioelements interactions; - the conditions of metabolites production during the microbial growth (influence of the nature of the carbonated source, pH effects, aerobiosis conditions...); the mechanisms of a direct effect for determining the importance of the bio-sorption mechanism by microorganisms; the fact that the microbial biomass can strongly interact with actinides, heavy metals and radioelements; the effects of microorganisms on storage materials (cement and clay) containing radioelements (uranium, cesium); the complexation capacities of the organic and mineral acids produced during the microbial growth. (O.M.)

  9. Amino Acid Block Copolymers with Broad Antimicrobial Activity and Barrier Properties.

    Science.gov (United States)

    Bevilacqua, Michael P; Huang, Daniel J; Wall, Brian D; Lane, Shalyn J; Edwards, Carl K; Hanson, Jarrod A; Benitez, Diego; Solomkin, Joseph S; Deming, Timothy J

    2017-10-01

    Antimicrobial properties of a long-chain, synthetic, cationic, and hydrophobic amino acid block copolymer are reported. In 5 and 60 min time-kill assays, solutions of K 100 L 40 block copolymers (poly(l-lysine·hydrochloride) 100 -b-poly(l-leucine) 40 ) at concentrations of 10-100 µg mL -1 show multi-log reductions in colony forming units of Gram-positive and Gram-negative bacteria, as well as yeast, including multidrug-resistant strains. Driven by association of hydrophobic segments, K 100 L 40 copolymers form viscous solutions and self-supporting hydrogels in water at concentrations of 1 and 2 wt%, respectively. These K 100 L 40 preparations provide an effective barrier to microbial contamination of wounds, as measured by multi-log decreases of tissue-associated bacteria with deliberate inoculation of porcine skin explants, porcine open wounds, and rodent closed wounds with foreign body. Based on these findings, amino acid copolymers with the features of K 100 L 40 can combine potent, direct antimicrobial activity and barrier properties in one biopolymer for a new approach to prevention of wound infections. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Aluminum oxide barrier coating on polyethersulfone substrate by atomic layer deposition for barrier property enhancement

    International Nuclear Information System (INIS)

    Kim, Hyun Gi; Kim, Sung Soo

    2011-01-01

    Aluminum oxide layers were deposited on flexible polyethersulfone (PES) substrates via plasma enhanced atomic layer deposition (PEALD) process using trimethylaluminum (TMA) and oxygen as precursor and reactant materials. Several process parameters in PEALD process were investigated in terms of refractive index and layer thickness. Number of process cycle increased the thickness and refractive index of the layer to enhance the barrier properties. Non-physisorbed TMA and unreacted oxygen were purged before and after the plasma reaction, respectively. Identical purge time was applied to TMA and oxygen and it was optimized for 10 s. Thinner and denser layer was formed as substrate temperature increased. However, the PES substrate could be deformed above 120 o C. Aluminum oxide layer formed on PES at optimized conditions have 11.8 nm of thickness and reduced water vapor transmission rate and oxygen transmission rate to below 4 x 10 -3 g/m 2 day and 4 x 10 -3 cm 3 /m 2 day, respectively. Polycarbonate and polyethylene naphthalate films were also tested at optimized conditions, and they also showed quite appreciable barrier properties to be used as plastic substrates.

  11. Graphene Oxide Bionanocomposite Coatings with High Oxygen Barrier Properties

    Directory of Open Access Journals (Sweden)

    Ilke Uysal Unalan

    2016-12-01

    Full Text Available In this work, we present the development of bionanocomposite coatings on poly(ethylene terephthalate (PET with outstanding oxygen barrier properties. Pullulan and graphene oxide (GO were used as main polymer phase and nanobuilding block (NBB, respectively. The oxygen barrier performance was investigated at different filler volume fractions (ϕ and as a function of different relative humidity (RH values. Noticeably, the impermeable nature of GO was reflected under dry conditions, in which an oxygen transmission rate (OTR, mL·m−2·24 h−1 value below the detection limit of the instrument (0.01 mL·m−2·24 h−1 was recorded, even for ϕ as low as 0.0004. A dramatic increase of the OTR values occurred in humid conditions, such that the barrier performance was totally lost at 90% RH (the OTR of coated PET films was equal to the OTR of bare PET films. Modelling of the experimental OTR data by Cussler’s model suggested that the spatial ordering of GO sheets within the main pullulan phase was perturbed because of RH fluctuations. In spite of the presence of the filler, all the formulations allowed the obtainment of final materials with haze values below 3%, the only exception being the formulation with the highest loading of GO (ϕ ≈ 0.03. The mechanisms underlying the experimental observations are discussed.

  12. Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

    Science.gov (United States)

    Zhu, Dongming; Miller, Robert A.

    2000-01-01

    Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  13. Psychometric Properties of the Barriers to Treatment Participation Scale-Expectancies

    NARCIS (Netherlands)

    Nanninga, Marieke; Jansen, Danielle E. M. C.; Kazdin, Alan E.; Knorth, Erik J.; Reijneveld, Sijmen A.

    Expectations concerning barriers to children's psychosocial care seem to be major drivers when seeking help, but validated questionnaires measuring expectations are not available. Therefore, this study examined the psychometric properties of the parent and adolescent versions of the Barriers to

  14. Fermented Camel Milk (Chal: Chemical, Microbial and Functional Properties

    Directory of Open Access Journals (Sweden)

    Maryam Salami

    2016-12-01

    Full Text Available The aim of this study was to determine physicochemical, microbial properties and antioxidant activity of fermented camel milk (Chal and introduce it as a functional food. The protein content of the samples was determined using Kjeldahl method and total dry matter using oven drying method. The amount of fat content with Gerber method and pH was measured using a pH meter. Antioxidant activity was also determined using 2,2’-azino-bis-(3-ethylbensothiazoline-6- sulfonic acid (ABTS method. The mineral analysis was performed with atomic absorption spectroscopy and microbial count by pour plate method. Results revealed that fat, protein content and total solid determined 5.82±0.27%, 3.07±0.073%, and 12.24±0.16%, respectively. Acidity and pH determined 80±7 °D and 4.52±0.10, respectively. When a food has calcium by itself, this calcium is bonded with the protein of food, this calcium is more effective in our body than the calcium we add to food and they have not bonded any proteins. Adequate calcium consumption may support to decrease the risk of osteoporosis in life. Calcium ranged 103.29±3.87% and phosphorus 10.25±0.1% for Chal samples, respectively. The total counts were equal 6.54±0.19 log CFUmL -1; Coliform count was determined in the ranges of 2.34±0.23 logCFUmL -1 for Chal samples. The results showed that Chal was rich in antioxidant. The antioxidant inhibitory activity of Chal was obtained 45.38%. Diets rich in antioxidants, can inhibit LDL oxidation, influence the activities of immune-competent cells and inhibit the formation of cell-to-cell adhesion factors. Therefore, Chal is introduced as a traditional functional food.

  15. Time-dependent effect of composted tannery sludge on the chemical and microbial properties of soil.

    Science.gov (United States)

    de Sousa, Ricardo Silva; Santos, Vilma Maria; de Melo, Wanderley Jose; Nunes, Luis Alfredo Pinheiro Leal; van den Brink, Paul J; Araújo, Ademir Sérgio Ferreira

    2017-12-01

    Composting has been suggested as an efficient method for tannery sludge recycling before its application to the soil. However, the application of composted tannery sludge (CTS) should be monitored to evaluate its effect on the chemical and microbial properties of soil. This study evaluated the time-dependent effect of CTS on the chemical and microbial properties of soil. CTS was applied at 0, 2.5, 5, 10, and 20 Mg ha -1 and the soil chemical and microbial properties were evaluated at 0, 45, 75, 150, and 180 days. Increased CTS rates increased the levels of Ca, Cr, and Mg. While Soil pH, organic C, and P increased with the CTS rates initially, this effect decreased over time. Soil microbial biomass, respiration, metabolic quotient, and dehydrogenase increased with the application of CTS, but decreased over time. Analysis of the Principal Response Curve showed a significant effect of CTS rate on the chemical and microbial properties of the soil over time. The weight of each variable indicated that all soil properties, except β-glucosidase, dehydrogenase and microbial quotient, increased due to the CTS application. However, the highest weights were found for Cr, pH, Ca, P, phosphatase and total organic C. The application of CTS in the soil changed the chemical and microbial properties over time, indicating Cr, pH, Ca, phosphatase, and soil respiration as the more responsive chemical and microbial variables by CTS application.

  16. Contribution of intestinal barrier damage, microbial translocation and HIV-1 infection status to an inflammaging signature.

    Directory of Open Access Journals (Sweden)

    Amanda K Steele

    Full Text Available Systemic inflammation is a characteristic of both HIV-1 infection and aging ("inflammaging". Intestinal epithelial barrier damage (IEBD and microbial translocation (MT contribute to HIV-associated inflammation, but their impact on inflammaging remains unclear.Plasma biomarkers for IEBD (iFABP, MT (LPS, sCD14, T-cell activation (sCD27, and inflammation (hsCRP, IL-6 were measured in 88 HIV-1 uninfected (HIV(neg and 83 treated, HIV-1-infected (HIV(pos adults from 20-100 years old.Age positively correlated with iFABP (r = 0.284, p = 0.008, sCD14 (r = 0.646, p = <0.0001 and LPS (r = 0.421, p = 0.0002 levels in HIV(neg but not HIV(pos subjects. Age also correlated with sCD27, hsCRP, and IL-6 levels regardless of HIV status. Middle-aged HIV(pos subjects had elevated plasma biomarker levels similar to or greater than those of elderly HIV(neg subjects with the exception of sCD14. Clustering analysis described an inflammaging phenotype (IP based on iFABP, sCD14, sCD27, and hsCRP levels in HIV(neg subjects over 60 years of age. The IP in HIV(neg subjects was used to develop a classification model that was applied to HIV(pos subjects to determine whether HIV(pos subjects under 60 years of age were IP+. HIV(pos IP+ subjects were similar in age to IP- subjects but had a greater risk of cardiovascular disease (CVD based on Framingham risk score (p =  0.01.We describe a novel IP that incorporates biomarkers of IEBD, MT, immune activation as well as inflammation. Application of this novel IP in HIV-infected subjects identified a group at higher risk of CVD.

  17. Barrier and mechanical properties of plasticized and cross-linked nanocellulose coatings for paper packaging applications

    OpenAIRE

    Herrera, M. A. (Martha A.); Mathew, A. P. (Aji P.); Oksman, K. (Kristiina)

    2017-01-01

    Abstract Barrier, mechanical and thermal properties of porous paper substrates dip-coated with nanocellulose (NC) were studied. Sorbitol plasticizer was used to improve the toughness, and citric acid cross-linker to improve the moisture stability of the coatings. In general, the addition of sorbitol increased the barrier properties, maximum strength and toughness as well as the thermal stability of the samples when compared to the non-modified NC coatings. The barrier properties significan...

  18. Microbial biosurfactants with their high-value functional properties

    Science.gov (United States)

    Microbial world is a rich source for finding valuable industrial chemicals and ingredients. Specifically, many microbial metabolites are surface-active compounds that can be developed into bio-based surfactants, detergents, and emulsifiers. Techno-economic analyses for the production of bio-based ...

  19. Soil microbial and physical properties and their relations along a steep copper gradient

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Møldrup, Per; Holmstrup, Martin

    2012-01-01

    years; from background concentrations up to 3837 mg Cu kg–1) on soil microbial enzyme activity, physical properties and resilience to compression. Soil samples and cores were taken from a fallow sandy loam field in Denmark. Microbial activity was quantified using fluorescein diacetate (FDA...

  20. Effects of a Chitosan Coating Layer on the Surface Properties and Barrier Properties of Kraft Paper

    Directory of Open Access Journals (Sweden)

    Shanhui Wang

    2016-01-01

    Full Text Available Biodegradable chitosan can be applied as a coating on the surface of kraft paper in order to improve its barrier properties against water vapor and air. The food packaging industry can benefit from the addition of chitosan to its current packaging, and in turn reduce pollution from plastic packaging plants. This paper discusses the film formation of chitosan, the permeability of paper coated with a chitosan layer, and the influence on the paper’s surface and barrier properties under different process conditions. SEM (scanning electron microscope, AFM (atomic force microscope, ATR-FTIR (Fourier transmission infrared spectroscope with attenuated total reflection, and PDA (penetration dynamics analysis were used to analyze the properties of chitosan’s film formation and permeability. A controlled experiment showed that the chitosan layer was smoother than the surface of the uncoated kraft paper, had better film formation, and that there was no chitosan penetration through the kraft paper. The barrier properties against water vapor were strongest when there was a higher concentration of chitosan solution at the optimum pH, stirring speed, and those with a thicker coating on the kraft paper.

  1. Transport properties of damaged materials. Cementitious barriers partnership

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2014-11-01

    The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

  2. Transport properties of damaged materials. Cementitious barriers partnership

    International Nuclear Information System (INIS)

    Langton, C.

    2014-01-01

    The objective of the Cementitious Barriers Partnership (CBP) project is to develop tools to improve understanding and prediction of the long-term structural, hydraulic, and chemical performance of cementitious barriers used in low-level waste storage applications. One key concern for the long-term durability of concrete is the degradation of the cementitious matrix, which occurs as a result of aggressive chemical species entering the material or leaching out in the environment, depending on the exposure conditions. The objective of the experimental study described in this report is to provide experimental data relating damage in cementitious materials to changes in transport properties, which can eventually be used to support predictive model development. In order to get results within a reasonable timeframe and to induce as much as possible uniform damage level in materials, concrete samples were exposed to freezing and thawing (F/T) cycles. The methodology consisted in exposing samples to F/T cycles and monitoring damage level with ultrasonic pulse velocity measurements. Upon reaching pre-selected damage levels, samples were tested to evaluate changes in transport properties. Material selection for the study was motivated by the need to get results rapidly, in order to assess the relevance of the methodology. Consequently, samples already available at SIMCO from past studies were used. They consisted in three different concrete mixtures cured for five years in wet conditions. The mixtures had water-to-cement ratios of 0.5, 0.65 and 0.75 and were prepared with ASTM Type I cement only. The results showed that porosity is not a good indicator for damage caused by the formation of microcracks. Some materials exhibited little variations in porosity even for high damage levels. On the other hand, significant variations in tortuosity were measured in all materials. This implies that damage caused by internal pressure does not necessarily create additional pore space in

  3. Aroma barrier properties of sodium caseinate-based films.

    Science.gov (United States)

    Fabra, Maria José; Hambleton, Alicia; Talens, Pau; Debeaufort, Fréderic; Chiralt, Amparo; Voilley, Andrée

    2008-05-01

    The mass transport of six different aroma compounds (ethyl acetate, ethyl butyrate, ethyl hexanoate, 2-hexanone, 1-hexanol, and cis-3-hexenol) through sodium caseinate-based films with different oleic acid (OA)/beeswax (BW) ratio has been studied. OA is less efficient than BW in reducing aroma permeability, which can be attributed to its greater polarity. Control film (without lipid) and films prepared with 0:100 OA/BW ratio show the lowest permeability. OA involves a decrease in aroma barrier properties of the sodium caseinate-based films due to its plasticization ability. Preferential sorption and diffusion occurs through OA instead of caseinate matrix and/or BW. The efficiency of sodium caseinate-based films to retain or limit aroma compound transfers depend on the affinity of the volatile compound to the films, which relates physicochemical interaction between volatile compound and film. Specific interactions (aroma compound-hydrocolloid and aroma compound-lipid) induce structural changes during mass transfer.

  4. Barrier, mechanical and optical properties of whey protein concentrate films

    Directory of Open Access Journals (Sweden)

    Viviane Machado Azevedo

    2014-08-01

    Full Text Available Whey is recognized as a valuable source of high quality protein and, when processed as protein concentrate, may be used in the production of biodegradable films. The objective of the study was to develop films of whey protein concentrate 80% (WPC at concentrations of 6, 8, 10 and 12% and evaluate the influence of this factor in the barrier, mechanical and optical properties of the films. Treatments showed moisture content with a mean value of 22.10% ± 0.76and high solubility values between 56.67 to 62.42%. Thus, there is little or no influence of varying the concentration of WPC in these properties and high hydrophilicity of the films. With increasing concentration of WPC, increases the water vapor permeability of the films (7.42 x 10-13 to 3.49 x 10-12 g.m-1.s-1.Pa-1. The treatment at the concentration of 6% of WPC showed a higher modulus of elasticity (287.90 ± 41.79 MPa. Thegreater rigidity in films with higher concentrations is possibly due to the greater number of bonds between molecules of the polymeric matrix. The films have the same puncture resistance. The increased concentration of WPC promotes resistance to the action of a localized force. In general, films of whey protein concentrate in the tested concentrations exhibited slightly yellowish color and transparency, and can be used in food packaging that requiring intermediate permeability to water vapor, to keep moisture and texture desired.

  5. Development of dielectric barrier discharge for reducing microbial contamination in pepper (Piper nigrum) and sesame (Sesamum indicum Linn.) powder

    Science.gov (United States)

    Promping, J.; Prakongsil, P.; Picha, R.; Traikool, T.

    2017-09-01

    This research is designed to determine the efficacy of DBD plasma to reduce the microbial contamination of pepper and sesame powder. The AC high voltage power supply was used with voltages of up to 20 kV and the frequency of 5.5 kHz was applied to the DBD. The gap of DBD electrodes was set at 5 mm. In raw initial samples, the total aerobic count of pepper (Piper nigrum) was found at quite a high level at 5.40 × 105 CFU/g. Coliform bacteria was also found in both the sesame (Sesamum indicum Linn.) powder and pepper (Piper nigrum) powder. Both kinds of samples were treated with plasma for 2, 4, 6 and 10 minutes. Results indicated that plasma treatment at 2-10 minutes reduced the total aerobic count of pepper allowed to achieve the acceptable microbial level for spices. The plasma treatment times in this experiment were also effective in reducing faecal coliform bacteria in both pepper and sesame powders (MPN/g <3) as indicated in the standard. Plasma from dielectric barrier charge can reduce Staphylococcus epidermidis in sesame powder which was artificially contaminated with 3.50 × 102 CFU/g resulting in 0.15-0.5 log cycle reductions of microbial load.

  6. Characterisation and functional properties of antimicrobial bio-barriers formed by natural fibres.

    Science.gov (United States)

    Tomšič, Brigita; Ilec, Eva; Žerjav, Metka; Hladnik, Aleš; Simončič, Andrej; Simončič, Barbara

    2014-10-01

    Antimicrobial bio-barriers formed on cotton (CO), silk (SE), and woollen (WO) fabrics were prepared by the application of 3-(trimethoxysilyl)-propyldimethyloctadecyl ammonium chloride (Si-QAC) at 11 concentrations ranging from 0.5% to 20% using an exhaustion method. The presence of the Si-QAC coating on the treated fabric samples was detected by X-ray photoelectron spectroscopy. The bromophenol blue reagent was used to determine the concentration of quaternary ammonium groups in the coating. The antimicrobial activity of the coated fibres against Gram-negative and Gram-positive bacteria (Escherichia coli and Staphylococcus aureus), fungi (Aspergillus niger and Chaetomium globosum), and soil microflora was assessed using standard microbiological methods. The antimicrobial protection of the fibres increased with increases in the applied concentration of Si-QAC. The fibre type strongly influenced the antimicrobial activity of Si-QAC. Si-QAC was most effective for CO fibres, less effective for WO fibres, and least effective for SE fibres, suggesting that Si-QAC is less accessible for interactions with microorganisms when applied to protein fibres than to cellulose. Although Si-QAC reduced the microbial growth, it did not significantly hinder the biodegradability or sustainability of the coated fibres when exposed to soil microflora. The extent of rotting was more influenced by the morphological and chemical properties of the fibres than by the presence of Si-QAC. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Properties of Whey-Protein-Coated Films and Laminates as Novel Recyclable Food Packaging Materials with Excellent Barrier Properties

    Directory of Open Access Journals (Sweden)

    Markus Schmid

    2012-01-01

    Full Text Available In case of food packaging applications, high oxygen and water vapour barriers are the prerequisite conditions for preserving the quality of the products throughout their whole lifecycle. Currently available polymers and/or biopolymer films are mostly used in combination with barrier materials derived from oil based plastics or aluminium to enhance their low barrier properties. In order to replace these non-renewable materials, current research efforts are focused on the development of sustainable coatings, while maintaining the functional properties of the resulting packaging materials. This article provides an introduction to food packaging requirements, highlights prior art on the use of whey-based coatings for their barriers properties, and describes the key properties of an innovative packaging multilayer material that includes a whey-based layer. The developed whey protein formulations had excellent barrier properties almost comparable to the ethylene vinyl alcohol copolymers (EVOH barrier layer conventionally used in food packaging composites, with an oxygen barrier (OTR of <2 [cm³(STP/(m²d bar] when normalized to a thickness of 100 μm. Further requirements of the barrier layer are good adhesion to the substrate and sufficient flexibility to withstand mechanical load while preventing delamination and/or brittle fracture. Whey-protein-based coatings have successfully met these functional and mechanical requirements.

  8. Effect of temperature on shelf life, chemical and microbial properties ...

    African Journals Online (AJOL)

    Cream cheese samples were analyzed to find out the effect of recommended storage temperature (4±1°C) and ambient room temperature (21±1°C) on pH, titratable acidity (% lactic acid), moisture content and microbial growth. Percent reduction in moisture content and increase in titratable acidity of cheeses were found to ...

  9. Effect of temperature on shelf life, chemical and microbial properties ...

    African Journals Online (AJOL)

    use

    2011-11-23

    Nov 23, 2011 ... and extrinsic factors (microbial quality of raw milk, production phases, ripening and packaging conditions, etc) (Prencipe et al., 2010; Hosny et al., 2011; Giammanco et al., 2011). Among the dairy products, cheese is the only product really susceptible to fungal growth and also production of mycotoxins.

  10. Microbial Load And Antimicrobial Property Of Two Nigerian Herbal ...

    African Journals Online (AJOL)

    Qualitative phytochemical screening of the herbal remedies revealed the presence of saponin, tannins, alkaloids, anthraquinone and cardiac glycosides which suggest possible antimicrobial effect. However, the presence of microbial contaminants in the herbal remedies suggests that they may serve as source of infection to ...

  11. Properties of Whey-Protein-Coated Films and Laminates as Novel Recyclable Food Packaging Materials with Excellent Barrier Properties

    OpenAIRE

    Markus Schmid; Kerstin Dallmann; Elodie Bugnicourt; Dario Cordoni; Florian Wild; Andrea Lazzeri; Klaus Noller

    2012-01-01

    In case of food packaging applications, high oxygen and water vapour barriers are the prerequisite conditions for preserving the quality of the products throughout their whole lifecycle. Currently available polymers and/or biopolymer films are mostly used in combination with barrier materials derived from oil based plastics or aluminium to enhance their low barrier properties. In order to replace these non-renewable materials, current research efforts are focused on the development of sustain...

  12. Reduction of microbial contamination and improvement of germination of sweet basil (Ocimum basilicum L.) seeds via surface dielectric barrier discharge

    Science.gov (United States)

    Ambrico, Paolo F.; Šimek, Milan; Morano, Massimo; De Miccolis Angelini, Rita M.; Minafra, Angelantonio; Trotti, Pasquale; Ambrico, Marianna; Prukner, Václav; Faretra, Francesco

    2017-08-01

    Naturally contaminated basil seeds were treated by a surface dielectric barrier discharge driven in the humid air by an amplitude modulated AC high voltage to avoid heat shock. In order to avoid direct contact of seeds with microdischarge filaments, the seeds to be treated were placed at sufficient distance from the surface discharge. After treatment, the seeds were analyzed in comparison with control samples for their microbial contamination as well as for the capability of germination and seedling growth. Moreover, chemical modification of seed surface was observed through the elemental energy dispersive x-ray analysis and wettability tests. We found that treatment applied at 20% duty cycle (effective discharge duration up to 20 s) significantly decreases microbial load without reducing the viability of the seeds. On the other side, seedling growth was considerably accelerated after the treatment, and biometric growth parameters of seedlings (total length, weight, leaf extension) considerably increased compared to the controls. Interestingly, scanning electron microscopy images taken for the different duration of treatment revealed that seed radicle micropylar regions underwent significant morphological changes while the coat was substantially undamaged. Inside the seed, the embryo seemed to be well preserved while the endosperm body was detached from the epithelial tegument. A total of 9 different genera of fungi were recovered from the analyzed seeds. Scanning electron microscopy images revealed that conidia were localized especially in the micropylar region, and after plasma treatment, most of them showed substantial damages. Therefore, the overall effect of the treatment of naturally contaminated seeds by reactive oxygen and nitrogen species produced by plasma and the consequent changes in surface chemistry and microbial load can significantly improve seed vigor.

  13. Reduction of microbial contamination and improvement of germination of sweet basil ( Ocimum basilicum L.) seeds via surface dielectric barrier discharge

    International Nuclear Information System (INIS)

    Ambrico, Paolo F; Ambrico, Marianna; Šimek, Milan; Prukner, Václav; Morano, Massimo; De Miccolis Angelini, Rita M; Trotti, Pasquale; Faretra, Francesco; Minafra, Angelantonio

    2017-01-01

    Naturally contaminated basil seeds were treated by a surface dielectric barrier discharge driven in the humid air by an amplitude modulated AC high voltage to avoid heat shock. In order to avoid direct contact of seeds with microdischarge filaments, the seeds to be treated were placed at sufficient distance from the surface discharge. After treatment, the seeds were analyzed in comparison with control samples for their microbial contamination as well as for the capability of germination and seedling growth. Moreover, chemical modification of seed surface was observed through the elemental energy dispersive x-ray analysis and wettability tests. We found that treatment applied at 20% duty cycle (effective discharge duration up to 20 s) significantly decreases microbial load without reducing the viability of the seeds. On the other side, seedling growth was considerably accelerated after the treatment, and biometric growth parameters of seedlings (total length, weight, leaf extension) considerably increased compared to the controls. Interestingly, scanning electron microscopy images taken for the different duration of treatment revealed that seed radicle micropylar regions underwent significant morphological changes while the coat was substantially undamaged. Inside the seed, the embryo seemed to be well preserved while the endosperm body was detached from the epithelial tegument. A total of 9 different genera of fungi were recovered from the analyzed seeds. Scanning electron microscopy images revealed that conidia were localized especially in the micropylar region, and after plasma treatment, most of them showed substantial damages. Therefore, the overall effect of the treatment of naturally contaminated seeds by reactive oxygen and nitrogen species produced by plasma and the consequent changes in surface chemistry and microbial load can significantly improve seed vigor. (paper)

  14. Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

    KAUST Repository

    Hayrapetyan, Suren; Kelarakis, Antonios; Estevez, Luis; Lin, Qin; Dana, Kausik; Chung, Yi-Lin; Giannelis, Emmanuel P.

    2012-01-01

    Motivated by the technological need for poly(ethylene terephthalate) materials with improved barrier properties together with the requirement for sustainability this study focuses on an eco-friendly sulfonated polyester as clay compatibilizer

  15. Simulation of thermo-Elastics Properties of Thermal Barrier Coatings ...

    African Journals Online (AJOL)

    Thermal barrier coatings are used to protect different parts in compressors and turbines from heat. They are generally composed of two layers, one metallic layer providing resistance to heat corrosion and oxidation, and one thermally insulating ceramic layer. Two different techniques are industrially used. Plasma spray ...

  16. Composite Films of Arabinoxylan and Fibrous Sepiolite: Morphological, Mechanical, and Barrier Properties

    DEFF Research Database (Denmark)

    Sárossy, Zsuzsa; Blomfeldt, J.O.; Hedenqvist, Mikael S.

    2012-01-01

    (ethylene glycol) methyl ether (mPEG) plasticizer addition. Incorporation of sepiolite did not significantly influence the thermal degradation or the gas barrier properties of arabinoxylan films, which is likely a consequence of sepiolite fiber morphology. In summary, sepiolite was shown to have potential...... as an additive to obtain stronger hemicellulose films although other approaches, possibly in combination with the use of sepiolite, would be needed if enhanced film barrier properties are required for specific applications....

  17. Ethylene vinyl alcohol: a review of barrier properties for packaging shelf stable foods.

    Science.gov (United States)

    Mokwena, K Khanah; Tang, Juming

    2012-01-01

    Ethylene vinyl alcohol (EVOH) is one of the best known flexible thermoplastic oxygen barrier materials in use today. It is especially important for refrigerated and shelf-stable foods where oxygen deteriorates the quality of packaged products and reduces their shelf life. EVOH accounts for a majority of thermoplastic barrier materials used for rigid or semi-rigid retortable food containers. However. it is of limited use in flexible packages or lid films for rigid trays used for packaging thermally processed shelf-stable low acid foods due to its moisture sensitivity. Nevertheless, current use of other oxygen barrier materials such as polyvinylidene chloride and aluminum foil creates environmental concerns. Innovations in food processing technologies provide opportunities for increased use of EVOH in food packaging. The aim of this review is to give an overview of research on the oxygen barrier properties of EVOH from the perspective of structure-barrier property relationships and the consequences of food processing conditions.

  18. THERMAL PROPERTIES OF TRANSPARENT BARRIER MODIFIED WITH ORGANIC PCMS

    Directory of Open Access Journals (Sweden)

    Michał MUSIAŁ

    2016-03-01

    Full Text Available Renewable energy sources are increasingly often applied in civil engineering as a mean to reduce buildings energy demand for heating. One of the ways to reduce HVAC energy demand is to limit heat transfer and excessive solar gain through building's glazed barriers. Preliminary results of the research conducted on organic PCM-modified transparent barrier are presented in this paper. Multiple publications concerning PCMs application in structural materials have recently appeared. Most of them are focused on modification of structure of non-transparent sections of buildings' envelope. Augmenting a glazed barrier with PCMs increases its heat capacity and thermal resistance. The most important feature of the assembly is the thermal buffer, a product of PCM's considerable value of specific latent heat. Research were conducted on a triple-pane transparent rectangular barrier, that constituted one of the faces of cubic chamber. Internal volume of the chamber was 1m3. The applied PCM was a mixture of saturated and non-saturated hydrocarbons. The described assembly was subjected to temperature and radiation that occur in Poland during winter. Glazing temperature, melted/total PCM ratio were measured, as well as energy demand for keeping internal temperature at constant level. Measurements were made in steady states, for various PCM layer thickness. The influence of the modification on energy demand was determined, along with the most effective and rational thickness of PCM layer to be applied. Conducted research enabled to develop a basis for further investigation of PCMs application in civil engineering.

  19. The effect of pH on hydrolysis, cross-linking and barrier properties of starch barriers containing citric acid.

    Science.gov (United States)

    Olsson, Erik; Menzel, Carolin; Johansson, Caisa; Andersson, Roger; Koch, Kristine; Järnström, Lars

    2013-11-06

    Citric acid cross-linking of starch for e.g. food packaging applications has been intensely studied during the last decade as a method of producing water-insensitive renewable barrier coatings. We managed to improve a starch formulation containing citric acid as cross-linking agent for industrial paper coating applications by adjusting the pH of the starch solution. The described starch formulations exhibited both cross-linking of starch by citric acid as well as satisfactory barrier properties, e.g. fairly low OTR values at 50% RH that are comparable with EVOH. Furthermore, it has been shown that barrier properties of coated papers with different solution pH were correlated to molecular changes in starch showing both hydrolysis and cross-linking of starch molecules in the presence of citric acid. Hydrolysis was shown to be almost completely hindered at solution pH≥4 at curing temperatures≤105 °C and at pH≥5 at curing temperatures≤150 °C, whereas cross-linking still occurred to some extent at pH≤6.5 and drying temperatures as low as 70 °C. Coated papers showed a minimum in water vapor transmission rate at pH 4 of the starch coating solution, corresponding to the point where hydrolysis was effectively hindered but where a significant degree of cross-linking still occurred. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Evaluation of diffusion barrier and electrical properties of tantalum oxynitride thin films for silver metallization

    International Nuclear Information System (INIS)

    Misra, E.; Wang, Y.; Theodore, N.D.; Alford, T.L.

    2004-01-01

    The thermal stability and the diffusion barrier properties of DC reactively sputtered tantalum oxynitride (Ta-O-N) thin films, between silver (Ag) and silicon (Si) p + n diodes were investigated. Both materials characterization (X-ray diffraction analysis, Rutherford backscattering spectrometry (RBS), Auger depth profiling) and electrical measurements (reverse-biased junction leakage current-density) were used to evaluate diffusion barrier properties of the thin films. The leakage current density of p + n diodes with the barrier (Ta-O-N) was approximately four orders of magnitude lower than those without barriers after a 30 min, 400 deg. C back contact anneal. The Ta-O-N barriers were stable up to 500 deg. C, 30 min anneals. However, this was not the case for the 600 deg. C anneal. RBS spectra and cross-sectional transmission electron microscopy of as-deposited and vacuum annealed samples of Ag/barrier (Ta-O-N)/Si indicate the absence of any interfacial interaction between the barrier and substrate (silicon). The failure of the Ta-O-N barriers has been attributed to thermally induced stresses, which cause the thin film to crack at elevated temperatures

  1. Time-dependent effect of composted tannery sludge on the chemical and microbial properties of soil

    NARCIS (Netherlands)

    Sousa, de Ricardo Silva; Santos, Vilma Maria; Melo, de Wanderley Jose; Nunes, Luis Alfredo Pinheiro Leal; Brink, van den Paul J.; Araújo, Ademir Sérgio Ferreira

    2017-01-01

    Composting has been suggested as an efficient method for tannery sludge recycling before its application to the soil. However, the application of composted tannery sludge (CTS) should be monitored to evaluate its effect on the chemical and microbial properties of soil. This study evaluated the

  2. Chemical and microbial properties in contaminated soils around a magnesite mine in northeast China

    Science.gov (United States)

    D Yang; D-H Zeng; J Zhang; L-J Li; R. Mao

    2012-01-01

    We measured soil chemical and microbial properties at a depth of 0–20 cm among mine tailings, abandoned mined land, contaminated cropland, and uncontaminated cropland around a magnesite mine near Haicheng City, Liaoning Province, China. The objective was to clarify the impact of Mg on the soils. We found that soluble Mg2+ concentration and pH...

  3. Volatile-mediated suppression of plant pathogens is related to soil properties and microbial community composition

    NARCIS (Netherlands)

    Van Agtmaal, M.; Straathof, A.L.; Termorshuizen, Aad J; Lievens, Bart; Hoffland, Ellis; De Boer, W.

    2018-01-01

    There is increasing evidence that the soil microbial community produces a suite of volatile organic compounds that suppress plant pathogens. However, it remains unknown which soil properties and management practices influence volatile-mediated pathogen suppression. The aim of this study was to

  4. Volatile-mediated suppression of plant pathogens is related to soil properties and microbial community composition

    NARCIS (Netherlands)

    Agtmaal, van Maaike; Straathof, Angela L.; Termorshuizen, Aad; Lievens, Bart; Hoffland, Ellis; Boer, de Wietse

    2018-01-01

    There is increasing evidence that the soil microbial community produces a suite of volatile organic compounds that suppress plant pathogens. However, it remains unknown which soil properties and management practices influence volatile-mediated pathogen suppression. The aim of this study was to

  5. A 3D-printed microbial cell culture platform with in situ PEGDA hydrogel barriers for differential substrate delivery.

    Science.gov (United States)

    Kadilak, Andrea L; Rehaag, Jessica C; Harrington, Cameron A; Shor, Leslie M

    2017-09-01

    Additive manufacturing, or 3D-printing techniques have recently begun to enable simpler, faster, and cheaper production of millifluidic devices at resolutions approaching 100-200  μ m. At this resolution, cell culture devices can be constructed that more accurately replicate natural environments compared with conventional culturing techniques. A number of microfluidics researchers have begun incorporating additive manufacturing into their work, using 3D-printed devices in a wide array of chemical, fluidic, and even some biological applications. Here, we describe a 3D-printed cell culture platform and demonstrate its use in culturing Pseudomonas putida KT2440 bacteria for 44 h under a differential substrate gradient. Polyethylene glycol diacrylate (PEGDA) hydrogel barriers are patterned in situ within a 3D-printed channel. Transport of the toluidine blue tracer dye through the hydrogel barriers is characterized. Nutrients and oxygen were delivered to cells in the culture region by diffusion through the PEGDA hydrogel barriers from adjacent media or saline perfusion channels. Expression of green fluorescent protein by P. putida KT2440 enabled real time visualization of cell density within the 3D-printed channel, and demonstrated cells were actively expressing protein over the course of the experiment. Cells were observed clustering near hydrogel barrier boundaries where fresh substrate and oxygen were being delivered via diffusive transport, but cells were unable to penetrate the barrier. The device described here provides a versatile and easy to implement platform for cell culture in readily controlled gradient microenvironments. By adjusting device geometry and hydrogel properties, this platform could be further customized for a wide variety of biological applications.

  6. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Directory of Open Access Journals (Sweden)

    Hudson Alves Silvério

    2014-12-01

    Full Text Available In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH30 on the mechanical, thermal, and barrier properties of methylcellulose (MC nanocomposites were evaluated. MC/WSH30 nanocomposite films with different filler levels (2, 4, 6, 8, and 10% were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH30, formation of a continuous network of WSH30 linked by hydrogen interactions and a close association between filler and matrix.

  7. Mechanical, thermal, and barrier properties of methylcellulose/cellulose nanocrystals nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Silverio, Hudson Alves; Flauzino Neto, Wilson Pires; Silva, Ingrid Souza Vieira da; Rosa, Joyce Rover; Pasquini, Daniel, E-mail: pasquini@iqufu.ufu.br, E-mail: danielpasquini2005@yahoo.com.br [Universidade de Uberlandia (USU), MG (Brazil). Instituto de Quimica; Assuncao, Rosana Maria Nascimento de [Universidade de Uberlandia (USU), Ituiutaba, MG (brazil). Fac. de Ciencias Integradas do Pontal; Barud, Hernane da Silva; Ribeiro, Sidney Jose Lima [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Araraquara, SP (Brazil). Instituto de Quimica

    2014-11-15

    In this work, the effects of incorporating cellulose nanocrystals from soy hulls (WSH{sub 30}) on the mechanical, thermal, and barrier properties of methylcellulose (MC) nanocomposites were evaluated. MC/WSH{sub 30} nanocomposite films with different filler levels (2, 4, 6, 8, and 10%) were prepared by casting. Compared to neat MC film, improvements in the mechanical and barrier properties were observed, while thermal stability was retained. The improved mechanical properties of nanocomposites prepared may be attributed to mechanical percolation of WSH{sub 30}, formation of a continuous network of WSH{sub 30} linked by hydrogen interactions and a close association between filler and matrix. (author)

  8. Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow's and Soymilk.

    Science.gov (United States)

    Temiz, Hasan; Dağyıldız, Kübra

    2017-01-01

    The objective of this research was to investigate the effects microbial transglutaminase (m-TGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein.

  9. Investigation of the Effects of Rosemary Extract on Barrier and Colorimetric Properties of Mungbean Starch Films

    Directory of Open Access Journals (Sweden)

    H. Safari Maznabi

    2013-08-01

    Full Text Available Barrier properties are one of the most important factors in the edible film. In this study, edible mungbean films were prepared containing (0%, 15%, 30%, 45% concentrations of rosemary aqueous extract. Then the effect of rosemary was investigated on colorimetric and barrier properties (water vapor permeability, oxygen permeability. Rosemary extract increased the absorption of color in the visible region, which in turn led to increase of the parameters a (index color tends toward green and b (index color tends towards yellow. The results showed that increasing concentrations of rosemary extract have a significant effect( p <0.05 to reduce the amount of oxygen and water vapor permeability.  Also turbidity of mungbean starch was increased with increasing concentrations of rosemary in the film. Improving barrier properties and the colorimetric properties were showed by rosemary extract compounds that these materials can use as the safety of food and pharmaceutical packaging industry.

  10. Antibacterial, mechanical, and barrier properties of sago starch film incorporated with Betel leaves extract.

    Science.gov (United States)

    Nouri, Leila; Mohammadi Nafchi, Abdorreza

    2014-05-01

    The antimicrobial, mechanical and barrier properties and light transmission of sago starch film incorporated with different percentage of Betel leaf extract (5%, 10%, 20%, and 30%) were evaluated. With regard to mechanical properties, tensile strength decreased when the percentage of extract increased. Elongation at break (%) and seal strength (N/m) increased with increasing percentage of extract from 5% to 20%, while decreased for films containing 30% extract due to heterogeneity of films in this percentage. With regard to barrier properties, water vapour and oxygen barrier properties decreased in all samples when percentage of the extract increased. Antimicrobial activity of all the films increased against both Gram positive and Gram negative bacteria as percentage of Betel leaf extract increased, except for Psuedomonas aeruginosa, which was not susceptible at any percentage of the extract. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. A study of the barrier properties of polyethylene coated with a nanocellulose/magnetite composite film

    Directory of Open Access Journals (Sweden)

    Đorđević Nenad

    2016-01-01

    Full Text Available The morphological, thermal and barrier properties of low-density polyethylene/polycaprolactone-modified nanocellulose hybrid materials were investigated in this paper. Nanonocelulose/magnetite (NC-Fe3O4 nanocomposite and maleic acid functionalized NC/magnetite (NCMA-Fe3O4 nanocomposite were prepared and used as filler at various concentrations (5, 10 and 15 wt. % in polycaprolactone (PCL layer. PE was coated with PCL/NC/magnetite layer. The addition of the filler did not unfavorably affect the inherent properties of the polymer, especially its barrier properties. Oxygen permeation measurements show that the oxygen barrier properties of magnetite enriched PCL film were improved due to chemical activity of added material. The highest level of barrier capacity was observed for PE samples coated with PCL based composite with NCMA-Fe3O4 micro/-nanofiller, which implies the significant contribution of nanocellulose surface modification with maleic anhydride residue to improved barrier properties. [Projekat Ministarstva nauke Republike Srbije, br. III45019 i br. OI172013

  12. Properties of dielectric barrier discharges in different arrangements

    International Nuclear Information System (INIS)

    Pietsch, G.J.

    2001-01-01

    Dielectric barrier discharges (DBDs) occur in arrangements where at least one dielectric is positioned in a gas space in between conducting electrodes. When breakdown field strength is reached in such a device, charge carriers are created in the gas region, accelerated, multiplied and finally collected on the surface(s) of the dielectric(s). The charge accumulation on the dielectric creates a counter field to that resulting from the power supply and as all of these processes are rather fast, the discharge quenches rapidly. The dielectric has two tasks, it limits the transferred charge and by this the energy conversion and distributes the discharge over the electrode area. That is why DBDs are non-thermal discharges which exist even at atmospheric pressure

  13. Designed cellulose nanocrystal surface properties for improving barrier properties in polylactide nanocomposites.

    Science.gov (United States)

    Espino-Pérez, Etzael; Bras, Julien; Almeida, Giana; Plessis, Cédric; Belgacem, Naceur; Perré, Patrick; Domenek, Sandra

    2018-03-01

    Nanocomposites are an opportunity to increase the performance of polymer membranes by fine-tuning their morphology. In particular, the understanding of the contribution of the polymer matrix/nanofiller interface to the overall transport properties is key to design membranes with tailored selective and adsorptive properties. In that aim, cellulose nanocrystals (CNC)/polylactide (PLA) nanocomposites were fabricated with chemically designed interfaces, which were ensuring the compatibility between the constituents and impacting the mass transport mechanism. A detailed analysis of the mass transport behaviour of different permeants in CNC/PLA nanocomposites was carried out as a function of their chemical affinity to grafted CNC surfaces. Penetrants (O 2 and cyclohexane), which were found to slightly interact with the constituents of the nanocomposites, provided information on the small tortuosity effect of CNC on diffusive mass transport. The mass transport of water (highly interacting with CNC) and anisole (interacting only with designed CNC surfaces) exhibited non-Fickian, Case II behaviour. The water vapour caused significant swelling of the CNC, which created a preferential pathway for mass transport. CNC surface grafting could attenuate this phenomenon and decrease the water transport rate. Anisole, an aromatic organic vapour, became reversibly trapped at the specifically designed CNC/PLA interface, but without any swelling or creation of an accelerated pathway. This caused the decrease of the overall mass transport rate. The latter finding could open a way to the creation of materials with specifically designed barrier properties by designing nanocomposites interfaces with specific interactions towards permeants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Discriminating Microbial Species Using Protein Sequence Properties and Machine Learning

    NARCIS (Netherlands)

    Shahib, Ali Al-; Gilbert, David; Breitling, Rainer

    2007-01-01

    Much work has been done to identify species-specific proteins in sequenced genomes and hence to determine their function. We assumed that such proteins have specific physico-chemical properties that will discriminate them from proteins in other species. In this paper, we examine the validity of this

  15. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Science.gov (United States)

    Periolatto, M.; Sangermano, M.; Spena, P. Russo

    2016-05-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  16. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Periolatto, M.; Spena, P. Russo [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, Bolzano (Italy); Sangermano, M. [Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, C.so Duca degli Abruzzi 24, Torino (Italy)

    2016-05-18

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  17. Permeation barrier properties of thin oxide films on flexible polymer substrates

    International Nuclear Information System (INIS)

    Fahlteich, John; Fahland, Matthias; Schoenberger, Waldemar; Schiller, Nicolas

    2009-01-01

    Solar cells and organic electronic devices require an encapsulation to ensure sufficient lifetime. Key parameters of the encapsulation are permeation barrier, UV stability, temperature stability, optical transmission spectra and mechanical stability. The requirements depend very much on the specific application. Many work groups suggest multilayer stacks to meet the permeation requirements. In this paper the permeation barrier properties of the different constituents of such a multilayer stack are characterized. Different layer materials are compared regarding their water vapour and oxygen permeability as well as the influence of process parameters is examined. Finally temperature dependent permeation measurements are used to characterize the permeation mechanisms in the different constituents of the multilayer barrier

  18. Photocured epoxy/graphene nanocomposites with enhanced water vapor barrier properties

    International Nuclear Information System (INIS)

    Periolatto, M.; Spena, P. Russo; Sangermano, M.

    2016-01-01

    A transparent, water vapor barrier film made of an epoxy resin and graphene oxide (GO) was synthesized by photopolymerization process. The epoxy/GO film with just 0.05 wt% GO gives a 93% WVTR reduction with respect to the pristine polymer, reaching barrier properties better than other polymer composites containing higher amounts of graphene. The excellent water vapor barrier is attributed to the good dispersion of GO in the polymer matrix. Moreover, GO significantly enhances the toughness and the damping capacity of the epoxy resins. The hybrid film can have potential applications in anticorrosive coatings, electronic devices, pharmaceuticals and food packaging.

  19. Microbial dynamics in petroleum oilfields and their relationship with physiological properties of petroleum oil reservoirs.

    Science.gov (United States)

    Varjani, Sunita J; Gnansounou, Edgard

    2017-12-01

    Petroleum is produced by thermal decay of buried organic material over millions of years. Petroleum oilfield ecosystems represent resource of reduced carbon which favours microbial growth. Therefore, it is obvious that many microorganisms have adapted to harsh environmental conditions of these ecosystems specifically temperature, oxygen availability and pressure. Knowledge of microorganisms present in ecosystems of petroleum oil reservoirs; their physiological and biological properties help in successful exploration of petroleum. Understanding microbiology of petroleum oilfield(s) can be used to enhance oil recovery, as microorganisms in oil reservoirs produce various metabolites viz. gases, acids, solvents, biopolymers and biosurfactants. The aim of this review is to discuss characteristics of petroleum oil reservoirs. This review also provides an updated literature on microbial ecology of these extreme ecosystems including microbial origin as well as various types of microorganisms such as methanogens; iron, nitrate and sulphate reducing bacteria, and fermentative microbes present in petroleum oilfield ecosystems. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Long-Term Effects of Legacy Copper Contamination on Microbial Activity and Soil Physical Properties

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Møldrup, Per; Holmstrup, Martin

    Soils heavily contaminated with copper (Cu) are considered unsuitable for agricultural use due to adverse impacts on microbial activity, soil physical properties, and direct toxicity to crops. This study investigated effects of Cu pollution from timber preservation activities between 1911 and 1924...... on soil micro-organisms and subsequent effects on physical properties of a sandy loam soil. Tillage operations over the last 70 years have caused spreading of the initially localized contamination and have created a Cu concentration gradient from 20 to 3800 mg kg-1 across an agricultural field in Hygum......, Denmark. Soil samples obtained from the fallow field were used to determine total microbial activity using fluorescein diacetate and dehydrogenase assays. The physical properties measured included water-dispersible clay, bulk density, air permeability and air-filled porosity. Significant differences...

  1. Assessment of Soil Health in Urban Agriculture: Soil Enzymes and Microbial Properties

    Directory of Open Access Journals (Sweden)

    Avanthi Deshani Igalavithana

    2017-02-01

    Full Text Available Urban agriculture has been recently highlighted with the increased importance for recreation in modern society; however, soil quality and public health may not be guaranteed because of continuous exposure to various pollutants. The objective of this study was to evaluate the soil quality of urban agriculture by soil microbial assessments. Two independent variables, organic and inorganic fertilizers, were considered. The activities of soil enzymes including dehydrogenase, β-glucosidase, arylsulfatase, urease, alkaline and acid phosphatases were used as indicators of important microbial mediated functions and the soil chemical properties were measured in the soils applied with organic or inorganic fertilizer for 10 years. Fatty acid methyl ester analysis was applied to determine the soil microbial community composition. Relatively higher microbial community richness and enzyme activities were found in the organic fertilizers applied soils as compared to the inorganic fertilizers applied soils. Principal component analysis explained the positive influence of organic fertilizers on the microbial community. The application of organic fertilizers can be a better alternative compared to inorganic fertilizers for the long-term health and security of urban agriculture.

  2. Microbial alkaline proteases: Optimization of production parameters and their properties

    Directory of Open Access Journals (Sweden)

    Kanupriya Miglani Sharma

    2017-06-01

    Full Text Available Proteases are hydrolytic enzymes capable of degrading proteins into small peptides and amino acids. They account for nearly 60% of the total industrial enzyme market. Proteases are extensively exploited commercially, in food, pharmaceutical, leather and detergent industry. Given their potential use, there has been renewed interest in the discovery of proteases with novel properties and a constant thrust to optimize the enzyme production. This review summarizes a fraction of the enormous reports available on various aspects of alkaline proteases. Diverse sources for isolation of alkaline protease producing microorganisms are reported. The various nutritional and environmental parameters affecting the production of alkaline proteases in submerged and solid state fermentation are described. The enzymatic and physicochemical properties of alkaline proteases from several microorganisms are discussed which can help to identify enzymes with high activity and stability over extreme pH and temperature, so that they can be developed for industrial applications.

  3. A biodegradable polymer nanocomposite: Mechanical and barrier properties

    Science.gov (United States)

    Lilichenko, N.; Maksimov, R. D.; Zicans, J.; Merijs Meri, R.; Plume, E.

    2008-01-01

    The preparation of an environmentally friendly nanocomposite based on plasticized potato starch and unmodified montmorillonite clay is described. Data on the influence of montmorillonite concentration on the mechanical properties of the materials obtained are reported. The effective elastic constants of the nanocomposites are calculated. The calculation results are compared with experimental data. The influence of montmorillonite content on the moisture permeability is also investigated.

  4. Alyssum homolocarpum seed gum-polyvinyl alcohol biodegradable composite film: Physicochemical, mechanical, thermal and barrier properties.

    Science.gov (United States)

    Monjazeb Marvdashti, Leila; Koocheki, Arash; Yavarmanesh, Masoud

    2017-01-02

    Films made from Alyssum homolocarpum seeds gum (AHSG) have poor mechanical and barrier (to oxygen) properties. In the present study poly vinyl alcohol (PVA) was used to improve the physicochemical properties of AHSG films. Results indicated that the addition of PVA significantly increased the moisture content, solubility, elongation at break (EB) and transparency while it decreased the density, oxygen permeability, chroma, water contact angle and Young modulus of AHSG based films. Films with higher AHSG to PVA ratios had lower water vapor permeability (WVP). The light barrier measurements presented low values of transparency at 600nm for PVA/AHSG films, indicating that films were very transparent while they had excellent barrier properties against UV light. Results for FTIR, DSC and SEM showed a clear interaction between PVA and AHSG, forming a new material. These results indicated that PVA/AHSG blend films had good compatibility. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Properties of internal transport barrier formation in JT-60U

    International Nuclear Information System (INIS)

    Sakamoto, Yoshiteru; Suzuki, T.; Ide, S.

    2003-01-01

    The dependence of the ion thermal diffusivity (χ i ) on the radial electric field (E r ) shear has been investigated in JT-60U plasmas. In positive magnetic shear (PS) plasmas, χ i in the core region generally increases with the heating power, similar to the L mode at low heating power. However, as a result of the intensive central heating, which is relevant to the enhancement of the E γ shear, a weak internal transport barrier (ITB) is formed, and χ i in the core region starts to decrease. Corresponding to a further increase of the heating power, a strong ITB is formed and χ i is reduced substantially. In the case of reversed magnetic shear (RS) plasmas, on the other hand, no power degradation of χ i is observed in any of heating regimes. The electron thermal diffusivity (χ e ) is strongly correlated with χ i in PS and RS plasmas. There exists a threshold in the effective E γ shear to change the state from a weak to a strong ITB. It is found that the threshold of the effective E γ shear in the case of a PS plasma depends on the poloidal magnetic field at the ITB. There are multiple levels of reduced transport in the strong ITB for RS plasmas. (author)

  6. Properties of internal transport barrier formation in JT-60U

    International Nuclear Information System (INIS)

    Sakamoto, Y.; Suzuki, T.; Ide, S.

    2003-01-01

    The dependence of the ion thermal diffusivity (χ i ) on the radial electric field (E r ) shear has been investigated in JT-60U plasmas. In positive magnetic shear (PS) plasmas, χ i in the core region generally increases with the heating power, similar to the L mode at low heating power. However, as a result of the intensive central heating, which is relevant to the enhancement of the E r shear, a weak internal transport barrier (ITB) is formed, and χ i in the core region starts to decrease. Corresponding to a further increase of the heating power, a strong ITB is formed and χ i is reduced substantially. In the case of reversed magnetic shear (RS) plasmas, on the other hand, no power degradation of χ i is observed in any of the heating regimes. The electron thermal diffusivity (χ e ) is strongly correlated with χ i in PS and RS plasmas. There exists a threshold in the effective E r shear to change the state from a weak to a strong ITB. It is found that the threshold of the effective E r shear in the case of a PS plasma depends on the poloidal magnetic field at the ITB. There are multiple levels of reduced transport in the strong ITB for RS plasmas. (author)

  7. Effects of 1-Alkyl-3-Methylimidazolium Nitrate on Soil Physical and Chemical Properties and Microbial Biomass.

    Science.gov (United States)

    Zhou, Tongtong; Wang, Jun; Ma, Zhiqiang; Du, Zhongkun; Zhang, Cheng; Zhu, Lusheng; Wang, Jinhua

    2018-05-01

    Ionic liquids (ILs), also called room temperature ILs, are widely applied in many fields on the basis of their unique physical and chemical properties. However, numerous ILs may be released into and gradually accumulate in the environment due to their extensive use and absolute solubility. The effects of 1-alkyl-3-methylimidazolium nitrate ([C n mim]NO 3 , n = 4, 6, 8) on soil pH, conductivity, cation exchange capacity, microbial biomass carbon, and microbial biomass nitrogen were examined at the doses of 1, 10, and 100 mg/kg on days 10, 20, 30, and 40. The results demonstrated that the soil pH decreased and the conductivity increased with increasing IL doses. No significant differences were observed in the soil cation-exchange capacity. All three of the tested ILs decreased the soil microbial biomass carbon and nitrogen. Additionally, there were few differences among the ILs with different alkyl chain lengths on the tested indicators except for the microbial biomass nitrogen. The present study addressed a gap in the literature regarding the effects of the aforementioned ILs with different alkyl side chains on the physicochemical properties of soil, and the results could provide the basic data for future studies on their toxicity to soil organisms, such as earthworms and soil microbes.

  8. Effects of different soil management practices on soil properties and microbial diversity

    Science.gov (United States)

    Gajda, Anna M.; Czyż, Ewa A.; Dexter, Anthony R.; Furtak, Karolina M.; Grządziel, Jarosław; Stanek-Tarkowska, Jadwiga

    2018-01-01

    The effects of different tillage systems on the properties and microbial diversity of an agricultural soil was investigated. In doing so, soil physical, chemical and biological properties were analysed in 2013-2015, on a long-term field experiment on a loamy sand at the IUNG-PIB Experimental Station in Grabów, Poland. Winter wheat was grown under two tillage treatments: conventional tillage using a mouldboard plough and traditional soil tillage equipment, and reduced tillage based on soil crushing-loosening equipment and a rigid-tine cultivator. Chopped wheat straw was used as a mulch on both treatments. Reduced tillage resulted in increased water content throughout the whole soil profile, in comparison with conventional tillage. Under reduced tillage, the content of readily dispersible clay was also reduced, and, therefore, soil stability was increased in the toplayers, compared with conventional tillage. In addition, the beneficial effects of reduced tillage were reflected in higher soil microbial activity as measured with dehydrogenases and hydrolysis of fluorescein diacetate, compared with conventional tillage. Moreover, the polimerase chain reaction - denaturing gradient gel electrophoresis analysis showed that soil under reduced till-age had greater diversity of microbial communities, compared with conventionally-tilled soil. Finally, reduced tillage increased organic matter content, stability in water and microbial diversity in the top layer of the soil.

  9. Transport properties of electrons in fractal magnetic-barrier structures

    Science.gov (United States)

    Sun, Lifeng; Fang, Chao; Guo, Yong

    2010-09-01

    Quantum transport properties in fractal magnetically modulated structures are studied by the transfer-matrix method. It is found that the transmission spectra depend sensitively not only on the incident energy and the direction of the wave vector but also on the stage of the fractal structures. Resonance splitting, enhancement, and position shift of the resonance peaks under different magnetic modulation are observed at four different fractal stages, and the relationship between the conductance in the fractal structure and magnetic modulation is also revealed. The results indicate the spectra of the transmission can be considered as fingerprints for the fractal structures, which show the subtle correspondence between magnetic structures and transport behaviors.

  10. The Barrier Properties of PET Coated DLC Film Deposited by Microwave Surface-Wave PECVD

    Science.gov (United States)

    Yin, Lianhua; Chen, Qiang

    2017-12-01

    In this paper we report the investigation of diamond-like carbon (DLC) deposited by microwave surface-wave plasma enhanced chemical vapor deposition (PECVD) on the polyethylene terephthalate (PET) web for the purpose of the barrier property improvement. In order to characterize the properties of DLC coatings, we used several substrates, silicon wafer, glass, and PET web and KBr tablet. The deposition rate was obtained by surface profiler based on the DLC deposited on glass substrates; Fourier transform infrared spectroscope (FTIR) was carried out on KBr tablets to investigate chemical composition and bonding structure; the morphology of the DLC coating was analyzed by atomic force microscope (AFM) on Si substrates. For the barrier properties of PET webs, we measured the oxygen transmission rate (OTR) and water vapor transmission rate (WVTR) after coated with DLC films. We addressed the film barrier property related to process parameters, such as microwave power and pulse parameter in this work. The results show that the DLC coatings can greatly improve the barrier properties of PET webs.

  11. Photochemical and microbial alterations of DOM spectroscopic properties in the estuarine system Ria de Aveiro.

    Science.gov (United States)

    Santos, L; Santos, E B H; Dias, J M; Cunha, A; Almeida, A

    2014-08-01

    The influence of photochemical transformations of chromophoric dissolved organic matter (CDOM) on microbial communities was evaluated in the estuarine system Ria de Aveiro. Two sites, representative of the marine and brackish water zones of the estuary, were surveyed regularly in order to determine seasonal and vertical profiles of variation of CDOM properties. Optical parameters of CDOM indicative of aromaticity and molecular weight were used to establish CDOM sources, and microbial abundance and activity was characterized. Additionally, microcosm experiments were performed in order to simulate photochemical reactions of CDOM and to evaluate microbial responses to light-induced changes in CDOM composition. The CDOM of the two estuarine zones showed different spectral characteristics, with significantly higher values of the specific ultra-violet absorbance at 254 nm (SUVA254) (5.5 times) and of the absorption coefficient at 350 nm (a350) (12 times) and lower SR (S275-295/S350-400) ratio at brackish water compared with the marine zone, reflecting the different amounts and prevailing sources of organic matter, as well as distinct riverine and oceanic influences. At the marine zone, the abundance of bacteria and the activity of Leu-AMPase correlated with a350 and a254, suggesting a microbial contribution to the HMW CDOM pool. The irradiation of DOM resulted in a decrease of the values of a254 and a350 and an increase of the slope S275-295 and of the ratios E2 : E3 (a250/a365) and SR, which in turn increase its bioavailability. However, the extent of photoinduced transformations and microbial responses was dependent on the initial optical characteristics of CDOM. In Ria de Aveiro both photochemical and microbial processes yielded optical changes in CDOM and the overall results of these combined processes determine the fate of CDOM in the estuarine system and have an influence on local productivity and in adjacent coastal areas.

  12. Xyloglucan, a Plant Polymer with Barrier Protective Properties over the Mucous Membranes: An Overview

    Directory of Open Access Journals (Sweden)

    Núria Piqué

    2018-02-01

    Full Text Available Disruption of the epithelial barrier function has been recently associated with a variety of diseases, mainly at intestinal level, but also affecting the respiratory epithelium and other mucosal barriers. Non-pharmacological approaches such as xyloglucan, with demonstrated protective barrier properties, are proposed as new alternatives for the management of a wide range of diseases, for which mucosal disruption and, particularly, tight junction alterations, is a common characteristic. Xyloglucan, a natural polysaccharide derived from tamarind seeds, possesses a “mucin-like” molecular structure that confers mucoadhesive properties, allowing xyloglucan formulations to act as a barrier capable of reducing bacterial adherence and invasion and to preserve tight junctions and paracellular flux, as observed in different in vitro and in vivo studies. In clinical trials, xyloglucan has been seen to reduce symptoms of gastroenteritis in adults and children, nasal disorders and dry eye syndrome. Similar mucosal protectors containing reticulated proteins have also been useful for the treatment of irritable bowel syndrome and urinary tract infections. The role of xyloglucan in other disorders with mucosal disruption, such as dermatological or other infectious diseases, deserves further research. In conclusion, xyloglucan, endowed with film-forming protective barrier properties, is a safe non-pharmacological alternative for the management of different diseases, such as gastrointestinal and nasal disorders.

  13. Effect of storage on physicochemical, microbial and antioxidant properties of pumpkin (Cucurbita moschata) candy

    OpenAIRE

    Sabeera Muzzaffar; Waqas N Baba; Nuzhat Nazir; F.A. Masoodi; Mohd Munaff Bhat; Rafiya Bazaz

    2016-01-01

    Pumpkin (Cucurbita moschata) is highly nutritious and antioxidant-rich vegetable widely grown all over the world. Present study reports the effect of storage on physicochemical, microbial, and antioxidant properties of pumpkin candy. Pumpkin and its candy were analyzed for the physicochemical characteristics like moisture content, ash, total soluble solids (TSS), titrable acidity, total sugar, reducing sugar, and color. Beta-carotene and vitamin-C content of pumpkin and its candy were also st...

  14. Transport properties of Dirac electrons in graphene based double velocity-barrier structures in electric and magnetic fields

    International Nuclear Information System (INIS)

    Liu, Lei; Li, Yu-Xian; Liu, Jian-Jun

    2012-01-01

    Using transfer matrix method, transport properties in graphene based double velocity-barrier structures under magnetic and electric fields are numerically studied. It is found that velocity barriers for the velocity ratio (the Fermi velocity inside the barrier to that outside the barrier) less than one (or for the velocity ratio greater than one) have properties similar to electrostatic wells (or barriers). The velocity barriers for the velocity ratio greater than one significantly enlarge the resonant tunneling region of electrostatic barriers. In the presence of magnetic field, the plateau width of the Fano factor with a Poissonian value shortens (or broadens) for the case of the velocity ratio less than one (or greater than one). When the Fermi energy is equal to the electrostatic barrier height, for different values of the velocity ratio, both the conductivities and the Fano factors remain fixed. -- Highlights: ► We model graphene based velocity-barrier structures in electric and magnetic fields. ► Velocity barrier for ξ 1) have property similar to electrostatic well (barrier). ► Velocity barrier for ξ>1 enlarge the resonant tunneling region of electrostatic barrier. ► The plateau width of Fano factor shortens (or broadens) for the case of ξ 1). ► The conductivity remains fixed at the point of E F =U 0 for different values of ξ.

  15. Physicochemical properties influencing denitrification rate and microbial activity in denitrification bioreactors

    Science.gov (United States)

    Schmidt, C. A.

    2012-12-01

    The use of N-based fertilizer will need to increase to meet future demands, yet existing applications have been implicated as the main source of coastal eutrophication and hypoxic zones. Producing sufficient crops to feed a growing planet will require efficient production in combination with sustainable treatment solutions. The long-term success of denitrification bioreactors to effectively remove nitrate (NO¬3), indicates this technology is a feasible treatment option. Assessing and quantifying the media properties that affect NO¬3 removal rate and microbial activity can improve predictions on bioreactor performance. It was hypothesized that denitrification rates and microbial biomass would be correlated with total C, NO¬3 concentration, metrics of organic matter quality, media surface area and laboratory measures of potential denitrification rate. NO¬3 removal rates and microbial biomass were evaluated in mesocosms filled with different wood treatments and the unique influence of these predictor variables was determined using a multiple linear regression analysis. NO3 reduction rates were independent of NO¬3 concentration indicating zero order reaction kinetics. Temperature was strongly correlated with denitrification rate (r2=0.87; Q10=4.7), indicating the variability of bioreactor performance in differing climates. Fiber quality, and media surface area were strong (R>0.50), unique predictors of rates and microbial biomass, although C:N ratio and potential denitrification rate did not predict actual denitrification rate or microbial biomass. Utilizing a stepwise multiple linear regression, indicates that the denitrification rate can be effectively (r2=0.56;pdetergent fiber and surface area alone are quantified. These results will assist with the widespread implementation of denitrification bioreactors to achieve significant N load reductions in large watersheds. The nitrate reduction rate as a function of groundwater temperature for all treatments

  16. Polymer/Silicate Nanocomposites Developed for Improved Thermal Stability and Barrier Properties

    Science.gov (United States)

    Campbell, Sandi G.

    2001-01-01

    The nanoscale reinforcement of polymers is becoming an attractive means of improving the properties and stability of polymers. Polymer-silicate nanocomposites are a relatively new class of materials with phase dimensions typically on the order of a few nanometers. Because of their nanometer-size features, nanocomposites possess unique properties typically not shared by more conventional composites. Polymer-layered silicate nanocomposites can attain a certain degree of stiffness, strength, and barrier properties with far less ceramic content than comparable glass- or mineral-reinforced polymers. Reinforcement of existing and new polyimides by this method offers an opportunity to greatly improve existing polymer properties without altering current synthetic or processing procedures.

  17. [Soil organic pollution characteristics and microbial properties in coal mining areas of Mentougou].

    Science.gov (United States)

    Jia, Jian-Li; Zhang, Yue; Wang, Chen; Li, Dong; Liu, Bo-Wen; Liu, Ying; Zhao, Le; Yang, Si-Qi

    2011-03-01

    Soil micro-ecosystem including organic pollution characteristics, basic physicochemical parameters, and microbial properties was analyzed which contaminated with organic pollutants in coal mining area. Results showed that the organic pollution level in coal mining area soils distributed from 0.4 to 1.5 mg/g dry soil, which was 1. 5-6 times as much as the background sample. Furthermore, the column chromatography and GC-MS analysis revealed that content of lightly components including saturated and aromatic hydrocarbons exceeded 40%, specifically was alkenes (> C15), hydrocarbon derivatives, and a small amount aromatic hydrocarbons. Totally, the components of organic pollutants extracted in soils were similar to which in coal gangue samples, illustrating the source of soil pollution to a certain extent in coal mining areas. The physicochemical factors such as nutrient level and moisture contents were not conducive to the growth and reproduction of microbe except pH level, which might show inhibition to microbial activities. Microbial density of pollutant soils in coal mining areas was totally low, with specific amount 10(4)-10(5) cell/g dry soil and FDA activity 2.0-2.9 mg/(g x min). Generally, the microbial density and activity were decreased as the enhancing pollution level. However, in-depth analysis was needed urgently because of the complex impact of environmental conditions like pH, moisture, and nutrition.

  18. The effect of the stretching of PLA extruded films on their crystallinity and gas barrier properties

    Science.gov (United States)

    Guinault, A.; Menary, G. H.; Courgneau, C.; Griffith, D.; Ducruet, V.; Miri, V.; Sollogoub, C.

    2011-05-01

    Driven by environmental concerns, new polymers based on renewable resources are arriving on the market to replace conventional polymers, obtained from petroleum, for different applications like food packaging. One of the most prominent polymers among these materials is poly(lactic acid) (PLA), a biodegradable, thermoplastic, aliphatic polyester derived from renewable resources, such as corn starch (in the USA) or sugarcanes (in the rest of the world). However this polymer presents different disadvantages and especially low gas barrier properties [1]. Thermal crystallization can be used to increase its gas barrier properties but long times are necessary [2] and are not compatible with an industrial process. Another way to increase the gas barrier properties consists in stretching the film in order to increase its crystallinity and so its diffusion coefficient. We have prepared stretched PLA films with different stretch ratio and we have studied the effect of the stretching parameters on the gas barrier properties of PLA films. Finally we compared this process with the isothermal crystallization process by taking into account the crystallinity degree and the crystalline morphology.

  19. CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces

    Science.gov (United States)

    2002-09-30

    CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces Alan W. Decho Department...TITLE AND SUBTITLE CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces 5a. CONTRACT...structures produced by bacteria. Their growth appears to depend on biofilm processes and light distributions ( photosynthesis ). Therefore, the data acquired

  20. Electrical and mechanical properties of Bi-2223/Ag/barrier/Ag composite tapes

    International Nuclear Information System (INIS)

    Kovac, P.; Husek, I.; Goemoery, F.; Oduleye, O.O.; Alford, N.McN.; Pachla, W.; Diduszko, R.

    2000-01-01

    Bi-2223/Ag/barrier/Ag single-core tapes with various oxide barrier materials (BaZrO 3 , SrCO 3 , ZrO 2 and Al 2 O 3 ) have been prepared by PIT. The I-V curves and ac susceptibility measurements have been performed for tapes with identical heat treatment history. Young's moduli of these tape samples have been evaluated by three-point bending and the structure of barrier powders and BSCCO cores was analysed by SEM and XRD, respectively. It was found that the shape of I-V curves, the current transfer lengths and the mechanical properties of tapes are all affected by the oxide barrier type and the barrier thickness, as well as by its porosity and uniformity. This is because the oxide barrier controls the oxygen diffusion during the tape heat treatment and simultaneously the HTS phase formation kinetics, its purity and content within the superconducting core. On the base of the results obtained for single-core tapes, two kinds of multifilamentary composite were made and tested. (author)

  1. Fabrication and properties of Ag-Bi2223 tapes with resistive barriers for filament decoupling

    International Nuclear Information System (INIS)

    Inada, Ryoji; Fukumoto, Yohei; Yasunami, Taeko; Nakamura, Yuichi; Oota, Akio; Li Chengshang; Zhang Pingxiang

    2007-01-01

    In this paper, we prepared the Bi2223 multifilamentary tapes with Ca 2 CuO 3 + Bi2212 as interfilamentary resistive barriers to suppress the electromagnetic coupling among the filaments under AC external magnetic field. The tapes with thin barrier layers of Ca 2 CuO 3 + 30 wt% Bi2212 around the filaments were prepared by using a standard powder-in-tube (PIT) method. The outside surface of monocore Ag-sheathed rods was coated by barrier materials. Then, the several coated monocore wires were stacked and packed into another Ag or Ag-Mg alloy tube. The packed tube was drawn and rolled into tape shape. The tape was subsequently sintered to form Bi2223 phase inside filaments. For the characterization of tapes, X-ray diffraction measurements were performed to investigate the phase formation inside the filaments. The uniformity of transport properties (J c ) for barrier tapes were evaluated on the order of several metre lengths and compared with the result for the tapes without barriers. Finally, AC loss characteristics under AC parallel transverse magnetic field were investigated to examine the effect of introducing the barriers on the filament decoupling

  2. Maple sap predominant microbial contaminants are correlated with the physicochemical and sensorial properties of maple syrup.

    Science.gov (United States)

    Filteau, Marie; Lagacé, Luc; Lapointe, Gisèle; Roy, Denis

    2012-03-01

    Maple sap processing and microbial contamination are significant aspects that affect maple syrup quality. In this study, two sample sets from 2005 and 2008 were used to assess the maple syrup quality variation and its relationship to microbial populations, with respect to processing, production site and harvesting period. The abundance of maple sap predominant bacteria (Pseudomonas fluorescens group and two subgroups, Rahnella spp., Janthinobacterium spp., Leuconostoc mesenteroides) and yeast (Mrakia spp., Mrakiella spp.,Guehomyces pullulans) was assessed by quantitative PCR. Maple syrup properties were analyzed by physicochemical and sensorial methods. Results indicate that P. fluorescens, Mrakia spp., Mrakiella spp. G. pullulans and Rahnella spp. are stable contaminants of maple sap, as they were found for every production site throughout the flow period. Multiple factor analysis reports a link between the relative abundance of P. fluorescens group and Mrakia spp. in maple sap with maple and vanilla odor as well as flavor of maple syrup. This evidence supports the contribution of these microorganisms or a consortium of predominant microbial contaminants to the characteristic properties of maple syrup. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Evaluation of catalytic properties of tungsten carbide for the anode of microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbaum, Miriam; Zhao, Feng; Quaas, Marion; Wulff, Harm; Schroeder, Uwe; Scholz, Fritz [Universitaet Greifswald, Institut fuer Biochemie, Felix-Hausdorff-Strasse 4, 17487 Greifswald (Germany)

    2007-07-31

    In this communication we discuss the properties of tungsten carbide, WC, as anodic electrocatalyst for microbial fuel cell application. The electrocatalytic activity of tungsten carbide is evaluated in the light of its preparation procedure, its structural properties as well as the pH and the composition of the anolyte solution and the catalyst load. The activity of the noble-metal-free electrocatalyst towards the oxidation of several common microbial fermentation products (hydrogen, formate, lactate, ethanol) is studied for microbial fuel cell conditions (e.g., pH 5, room temperature and ambient pressure). Current densities of up to 8.8 mA cm{sup -2} are achieved for hydrogen (hydrogen saturated electrolyte solution), and up to 2 mA cm{sup -2} for formate and lactate, respectively. No activity was observed for ethanol electrooxidation. The electrocatalytic activity and chemical stability of tungsten carbide is excellent in acidic to pH neutral potassium chloride electrolyte solutions, whereas higher phosphate concentrations at neutral pH support an oxidative degradation. (author)

  4. Effect of hydrogen on the diode properties of reactively sputtered amorphous silicon Schottky barrier structures

    International Nuclear Information System (INIS)

    Morel, D.L.; Moustakas, T.D.

    1981-01-01

    The diode properties of reactively sputtered hydrogenated amorphous silicon Schottky barrier structures (a-SiH/sub x/ /Pt) have been investigated. We find a systematic relation between the changes in the open circuit voltage, the barrier height, and the diode quality factor. These results are accounted for by assuming that hydrogen incorporation into the amorphous silicon network removes states from the top of the valence band and sharpens the valence-band tail. Interfacial oxide layers play a significant role in the low hydrogen content, and low band-gap regime

  5. Tuning biomimetic membrane barrier properties by hydrocarbon, cholesterol and polymeric additives

    DEFF Research Database (Denmark)

    Palanco, Marta Espina; Skovgaard, Nils; Hansen, Jesper Søndergaard

    2017-01-01

    The barrier properties of cellular membranes are increasingly attracting attention as a source of inspiration for designing biomimetic membranes. The broad range of potential technological applications makes the use of lipid and lately also polymeric materials a popular choice for constructing...... biomimetic membranes, where the barrier properties can be controlled by the composition of the membrane constituent elements. Here we investigate the membrane properties reported by the light-induced proton pumping activity of bacteriorhodopsin (bR) reconstituted in three vesicle systems of different...... membrane composition. Specifically we quantify how the resulting proton influx and efflux rates are influenced by the membrane composition using a variety of membrane modulators. We demonstrate that by adding hydrocarbons to vesicles with reconstituted bR formed from asolectin lipids the resulting...

  6. Nonmetallic engineered barriers, their properties and role in a geologic repository for high level radioactive waste

    International Nuclear Information System (INIS)

    Lisy, F.

    1994-01-01

    The efficiency of engineered barrier systems depends to a great extent on the properties of the materials used. Backfill and sealing materials must fulfill certain requirements and criteria. They must feature low hydraulic conductivity, high retardation capacity, extremely good sorption properties for a wide range of radionuclides potentially leachable from the deposited waste, low permeability, good compatibility with engineered and natural barriers, good workability, and availability in the necessary quantity and at a reasonable price. Some basic properties are presented of materials which fulfill, to a considerable degree, these requirements and which are thus suggested as suitable backfills, sealings of buffers, namely clay- and cement-based materials (concretes, mortars, etc.). A brief information is also given on some other materials like bitumen, asphalt, etc. (Z.S.) 4 refs

  7. Relationships between waste physicochemical properties, microbial activity and vegetation at coal ash and sludge disposal sites.

    Science.gov (United States)

    Woch, Marcin W; Radwańska, Magdalena; Stanek, Małgorzata; Łopata, Barbara; Stefanowicz, Anna M

    2018-06-11

    The aim of the study was to assess the relationships between vegetation, physicochemical and microbial properties of substrate at coal ash and sludge disposal sites. The study was performed on 32 plots classified into 7 categories: dried ash sedimentation ponds, dominated by a grass Calamagrostis epigejos (AH-Ce), with the admixture of Pinus sylvestris (AH-CePs) or Robinia pseudoacacia (AH-CeRp), dry ash landfill dominated by Betula pendula and Pinus sylvestris (AD-BpPs) or Salix viminalis (AD-Sv) and coal sludge pond with drier parts dominated by Tussilago farfara (CS-Tf) and the wetter ones by Cyperus flavescens (CS-Cf). Ash sites were covered with soil layer imported as a part of technical reclamation. Ash had relatively high concentrations of some alkali and alkaline earth metals, Mn and pH, while coal sludge had high water and C, S, P and K contents. Concentrations of heavy metals were lower than allowable limits in all substrate types. Microbial biomass and, particularly, enzymatic activity in ash and sludge were generally low. The only exception were CS-Tf plots characterized by the highest microbial biomass, presumably due to large deposits of organic matter that became available for aerobic microbial biomass when water level fell. The properties of ash and sludge adversely affected microbial biomass and enzymatic activity as indicated by significant negative correlations between the content of alkali/alkaline earth metals, heavy metals, and macronutrients with enzymatic activity and/or microbial biomass, as well as positive correlations of these parameters with metabolic quotient (qCO 2 ). Plant species richness and cover were relatively high, which may be partly associated with alleviating influence of soil covering the ash. The effect of the admixture of R. pseudoacacia or P. sylvestris to stands dominated by C. epigejos was smaller than expected. The former species increased NNH 4 , NNO 3 and arylsulfatase activity, while the latter reduced activity of

  8. Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment

    Directory of Open Access Journals (Sweden)

    Chi-Wai Kan

    2013-01-01

    Full Text Available Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment.

  9. Barrier Properties and Structural Study of Nanocomposite of HDPE/Montmorillonite Modified with Polyvinylalcohol

    Directory of Open Access Journals (Sweden)

    María C. Carrera

    2013-01-01

    Full Text Available In this work was studied the permeation of CO2 in films of high-density polyethylene (HDPE and organoclay modified with polyvinylalcohol (MMTHDTMA/PVA obtained from melt blending. Permeation study showed that the incorporation of the modified organoclay generates a significant effect on the barrier properties of HDPE. When a load of 2 wt% of MMTHDTMA/PVA was incorporated in the polymer matrix, the flow of CO2 decreased 43.7% compared to pure polyethylene. The results of TEM showed that clay layers were dispersed in the polymeric matrix, obtaining an exfoliated-structure nanocomposite. The thermal stability of nanocomposite was significantly enhanced with respect to the pristine HDPE. DSC results showed that the crystallinity was maintained as the pure polymeric matrix. Consequently, the decrease of permeability was attributable only to the effect of tortuosity generated by the dispersion of MMTHDTMA/PVA. Notably the mechanical properties remain equal to those of pure polyethylene, but with an increase in barrier properties to CO2. This procedure allows obtaining nanocomposites of HDPE with a good barrier property to CO2 which would make it competitive in the use of packaging.

  10. Effect of Microwave Treatment on Microbial Contamination of Honeys and on Their Physicochemical and Thermal Properties

    Directory of Open Access Journals (Sweden)

    Paz Moliné María de la

    2015-06-01

    Full Text Available In recent years, microwave heating has become a common method for pasteurization and sterilization of food. Honey is a sweet substance produced by worker honeybees from nectar of flowers. The major microbial contaminants include moulds and yeasts, as well as the spore-forming bacteria, being their counts indicative of honeys’ commercial quality and safety. Paenibacillus larvae is also of interest since it causes American foulbrood (AFB in honeybee larvae. The main quality factors that are used in the honey international trade are moisture, hydroxymethylfurfural content (HMF, and enzymatic indices. Moreover, honey exhibits several thermal events, the most important being the glass transition temperature (Tg. The aim of this work was to evaluate microwave effect (800 watts during 45 and 90 seconds on microbial content in particular over P. larvae spores retained in honey, and on physicochemical and thermal properties. Microwave promoted a decrease of microbial count with time of exposure, including P. larvae. Moisture content diminished after treatment, while Tg increased linearly, and acidity decremented in the majority of cases. Honeys darkened and HMF exceeded the permissible value. Diastase and glucose-oxidase enzymes were totally inactivated by microwave treatment.

  11. Impact of Organic and Conventional Systems of Coffee Farming on Soil Properties and Culturable Microbial Diversity.

    Science.gov (United States)

    Velmourougane, Kulandaivelu

    2016-01-01

    A study was undertaken with an objective of evaluating the long-term impacts of organic (ORG) and conventional (CON) methods of coffee farming on soil physical, chemical, biological, and microbial diversity. Electrical conductivity and bulk density were found to increase by 34% and 21%, respectively, in CON compared to ORG system, while water holding capacity was found decreased in both the systems. Significant increase in organic carbon was observed in ORG system. Major nutrients, nitrogen and potassium, levels showed inclination in both ORG and CON system, but the trend was much more pronounced in CON system. Phosphorus was found to increase in both ORG and CON system, but its availability was found to be more with CON system. In biological attributes, higher soil respiration and fluorescein diacetate activity were recorded in ORG system compared to CON system. Higher soil urease activity was observed in CON system, while dehydrogenase activity does not show significant differences between ORG and CON systems. ORG system was found to have higher macrofauna (31.4%), microbial population (34%), and microbial diversity indices compared to CON system. From the present study, it is accomplished that coffee soil under long-term ORG system has better soil properties compared to CON system.

  12. Microbial properties explain temporal variation in soil respiration in a grassland subjected to nitrogen addition

    Science.gov (United States)

    Li, Yue; Liu, Yinghui; Wu, Shanmei; Niu, Lei; Tian, Yuqiang

    2015-01-01

    The role of soil microbial variables in shaping the temporal variability of soil respiration has been well acknowledged but is poorly understood, particularly under elevated nitrogen (N) deposition conditions. We measured soil respiration along with soil microbial properties during the early, middle, and late growing seasons in temperate grassland plots that had been treated with N additions of 0, 2, 4, 8, 16, or 32 g N m−2 yr−1 for 10 years. Representing the averages over three observation periods, total (Rs) and heterotrophic (Rh) respiration were highest with 4 g N m−2 yr−1, but autotrophic respiration (Ra) was highest with 8 to 16 g N m−2 yr−1. Also, the responses of Rh and Ra were unsynchronized considering the periods separately. N addition had no significant impact on the temperature sensitivity (Q10) for Rs but inhibited the Q10 for Rh. Significant interactions between observation period and N level occurred in soil respiration components, and the temporal variations in soil respiration components were mostly associated with changes in microbial biomass carbon (MBC) and phospholipid fatty acids (PLFAs). Further observation on soil organic carbon and root biomass is needed to reveal the long-term effect of N deposition on soil C sequestration. PMID:26678303

  13. Potential contribution of microbial communities in technical ceramics for the improvement of rheological properties

    Science.gov (United States)

    Moreira, Bernardino; Miller, Ana Z.; Santos, Ricardo; Monteiro, Sílvia; Dias, Diamantino; Neves, Orquídia; Dionísio, Amélia; Saiz-Jimenez, Cesareo

    2014-05-01

    Several bacterial and fungal species naturally occurring in ceramic raw materials used in construction, such as Aspergillus, Penicillium and Aureobasidium, are known to produce exopolysaccharides (EPS). These polymers excreted by the cells are of widespread occurrence and may confer unique and potentially interesting properties with potential industrial uses, such as viscosity control, gelation, and flocculation, during ceramic manufacturing. In this study, the microbial communities present in clay raw materials were identified by both cultural methods and DNA-based molecular techniques in order to appraise their potential contribution to enhance the performance of technical ceramics through the use of EPS. Mineralogical identification by X- Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy of the clay raw materials, as well as characterization of rheological properties of ceramic slips were also performed. Microbial EPS production and its introduction into ceramic slips will be then carried out in order to evaluate their effects on the rheological properties of the ceramic slips, powders and conformed bodies. Some positive aspects related to the use of EPS are: reduction of the environmental impact caused by synthetic organic additives, reduction of production costs, as well as the costs related with operator protection systems, gaseous effluent treatments, complex landfill, among others.

  14. Influence of ionizing radiation and use of plasticizers on the mechanical properties and barrier properties of biodegradable films

    International Nuclear Information System (INIS)

    Ponce, Patricia; Parra, Duclerc F.; Carr, Laura G.; Sato, Juliana S.; Lugao, Ademar B.

    2005-01-01

    This work reports the influence of radiation and plasticizers on the barrier properties [water vapour permeability (WVP)] and mechanical properties (tensile strength and elongation) of edible films made of starch. These films were prepared with 4 g of starch/100 mL of water; 2-10 g polyethylene glycol (PEG)/100 g starch; and at natural pH. Tensile strength and percentage elongation were measured using a Mechanical Universal Testing Machine Instron 4400R and the water vapour permeability was determined according to ASTM E96-80 (ASTM, 1989). The mechanical properties of starch films are influenced by the plasticizer concentration. An increase in PEG content showed a considerable increase in elongation percentage and a decrease in the tensile strength of the films, also increase the permeability of the films in water. After irradiation, the barrier properties [water vapour permeability (WVP)] and mechanical properties (tensile strength and elongation) of the films were improved due to chemical reactions among polymer molecules. The films were irradiated at room temperature with gamma radiation. Irradiated starch cassava films with polyethylene glycol (PEG) as plasticizer have good flexibility and low water permeability, which indicate potential application as edible films (author)

  15. Moisture barrier properties of single-layer graphene deposited on Cu films for Cu metallization

    Science.gov (United States)

    Gomasang, Ploybussara; Abe, Takumi; Kawahara, Kenji; Wasai, Yoko; Nabatova-Gabain, Nataliya; Thanh Cuong, Nguyen; Ago, Hiroki; Okada, Susumu; Ueno, Kazuyoshi

    2018-04-01

    The moisture barrier properties of large-grain single-layer graphene (SLG) deposited on a Cu(111)/sapphire substrate are demonstrated by comparing with the bare Cu(111) surface under an accelerated degradation test (ADT) at 85 °C and 85% relative humidity (RH) for various durations. The change in surface color and the formation of Cu oxide are investigated by optical microscopy (OM) and X-ray photoelectron spectroscopy (XPS), respectively. First-principle simulation is performed to understand the mechanisms underlying the barrier properties of SLG against O diffusion. The correlation between Cu oxide thickness and SLG quality are also analyzed by spectroscopic ellipsometry (SE) measured on a non-uniform SLG film. SLG with large grains shows high performance in preventing the Cu oxidation due to moisture during ADT.

  16. Dependence of the Josephson coupling of unconventional superconductors on the properties of the tunneling barrier

    International Nuclear Information System (INIS)

    Ledvij, M.; Klemm, R.A.

    1994-01-01

    The Josephson coupling between a conventional and an unconventional superconductor is investigated as a function of the properties of the tunneling barrier. A simple model is adopted for the tunneling probability and it is shown that its variation dramatically affects the I c R n product of an s-d, as opposed to an s-s junction. Based on these conclusions, experiments are proposed to probe the symmetry of the order parameter in high temperature superconductors

  17. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate)/Graphene Oxide Nanocomposites

    OpenAIRE

    Szymczyk, Anna; Paszkiewicz, Sandra; Pawelec, Iwona; Lisiecki, Slawomir; Jotko, Marek; Spitalsky, Zdenko; Mosnácek, Jaroslav; Roslaniec, Zbigniew

    2015-01-01

    Poly(ethylene terephthalate) nanocomposites with low loading (0.1–0.5 wt%) of graphene oxide (GO) have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for ...

  18. Psychometric properties of the Exercise Benefits/Barriers Scale in Mexican elderly women

    Directory of Open Access Journals (Sweden)

    María Cristina Enríquez-Reyna

    Full Text Available ABSTRACT Objective: analyze and assess the psychometric properties of the subscales in the Spanish version of the Exercise Benefits/Barriers Scale in an elderly population in the Northeast of Mexico. Method: methodological study. The sample consisted of 329 elderly associated with one of the five public centers for senior citizens in the metropolitan area of Northeast Mexico. The psychometric properties included the assessment of the Cronbach's alpha coefficient, the Kaiser Meyer Olkin coefficient, the inter-item correlation, exploratory and confirmatory factor analysis. Results: in the principal components analysis, two components were identified based on the 43 items in the scale. The item-total correlation coefficient of the exercise benefits subscale was good. Nevertheless, the coefficient for the exercise barriers subscale revealed inconsistencies. The reliability and validity were acceptable. The confirmatory factor analysis revealed that the elimination of items improved the goodness of fit of the baseline scale, without affecting its validity or reliability. Conclusion: the Exercise Benefits/Barriers subscale presented satisfactory psychometric properties for the Mexican context. A 15-item short version is presented with factorial structure, validity and reliability similar to the complete scale.

  19. Effects of modified cellulose nanocrystals on the barrier and migration properties of PLA nano-biocomposites.

    Science.gov (United States)

    Fortunati, E; Peltzer, M; Armentano, I; Torre, L; Jiménez, A; Kenny, J M

    2012-10-01

    The aim of this paper is to report the impact of the addition of cellulose nanocrystals on the barrier properties and on the migration behaviour of poly(lactic acid), PLA, based nano-biocomposites prepared by the solvent casting method. Their microstructure, crystallinity, barrier and overall migration properties were investigated. Pristine (CNC) and surfactant-modified cellulose nanocrystals (s-CNC) were used, and the effect of the cellulose modification and content in the nano-biocomposites was investigated. The presence of surfactant on the nanocrystal surface favours the dispersion of CNC in the PLA matrix. Electron microscopy analysis shows the good dispersion of s-CNC in the nanoscale with well-defined single crystals indicating that the surfactant allowed a better interaction between the cellulose structures and the PLA matrix. Reductions of 34% in water permeability were obtained for the cast films containing 1 wt.% of s-CNC while good oxygen barrier properties were detected for nano-biocomposites with both 1 wt.% and 5 wt.% of modified and un-modified cellulose nanocrystals, underlining the improvement provided by cellulose on the PLA films. Moreover, the migration level of the studied nano-biocomposites was below the overall migration limits required by the current normative for food packaging materials in both non-polar and polar simulants. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Preparation, characterization, mechanical, barrier and antimicrobial properties of chitosan/PVOH/clay nanocomposites.

    Science.gov (United States)

    Giannakas, Aris; Vlacha, Maria; Salmas, Constantinos; Leontiou, Areti; Katapodis, Petros; Stamatis, Haralambos; Barkoula, Nektaria-Marianthi; Ladavos, Athanasios

    2016-04-20

    In the current study low molecular weight poly(vinylalcohol) (PVOH) was used to prepare chitosan/PVOH blends and chitosan/PVOH/montmorillonite nanocomposites via a reflux - solution - heat pressing method. The effect of PVOH content and montmorillonite type (hydrophylic vs. organically modified) on the morphology, mechanical, thermomechanical, barrier and antimicrobial properties of the obtained polymer blends and nanocomposite films was studied. Higher amounts of PVOH (20 and 30%) resulted in plasticization of the films, with an increase in the elongation at break and decrease of the stiffness and the strength while effective blending between chitosan and PVOH chains was observed based on the XRD and DMA findings. Addition of PVOH was beneficial for water and oxygen barrier properties of the obtained films while it did not influence the antimicrobial activity of films against the growth of Escherichia coli. Intercalated structures were obtained after the addition of hydrophilic and organo-modified clays leading into stiffening of the nano-modified films and enhancement of their barrier and antimicrobial properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Thermal Shock Property of Al/Ni-ZrO2 Gradient Thermal Barrier Coatings

    Institute of Scientific and Technical Information of China (English)

    FANJin-juan; WANGQuan-sheng; ZHANGWei-fang

    2004-01-01

    Al/Ni-ZrO2 gradient thermal barrier coatings are made on aluminum substrate using plasma spraying method and one direction thermal shock properties of the coatings are studied in this paper. The results show that pores in coatings link to form cracks vertical to coating surface. They go through the whole ZrO2 coating once vertical cracks form. When thermal shock cycles increase, horizontal cracks that result in coatings failure forms in the coatings and interface. And vertical cracks delay appearance of horizontal cracks and enhance thermal shock property of coatings. Failure mechanisms of coating thermal shock are discussed using experiments and finite element method.

  2. Non-toxic poly(ethylene terephthalate)/clay nanocomposites with enhanced barrier properties

    KAUST Repository

    Hayrapetyan, Suren

    2012-01-01

    Motivated by the technological need for poly(ethylene terephthalate) materials with improved barrier properties together with the requirement for sustainability this study focuses on an eco-friendly sulfonated polyester as clay compatibilizer to facilitate polymer mixing during melt compounding. We demonstrate that the nanocomposites based on sulfonated polyester are a reliable alternative to their imidazolium counterparts, exhibiting enhanced properties (water vapor and UV transmission), without sacrificing the excellent transparency, clarity and mechanical strength of the matrix. © 2011 Elsevier Ltd. All rights reserved.

  3. Mechanical Properties of Air Plasma Sprayed Environmental Barrier Coating (EBC) Materials

    Science.gov (United States)

    Richards, Bradley; Zhu, Dongming; Ghosn, Louis; Wadley, Haydn

    2015-01-01

    Development work in Environmental Barrier Coatings (EBCs) for Ceramic Matrix Composites (CMCs) has focused considerably on the identification of materials systems and coating architectures to meet application needs. The evolution of these systems has occurred so quickly that modeling efforts and requisite data for modeling lag considerably behind development. Materials property data exists for many systems in the bulk form, but the effects of deposition on the critical properties of strength and fracture behavior are not well studied. We have plasma sprayed bulk samples of baseline EBC materials (silicon, ytterbium disilicate) and tested the mechanical properties of these materials to elicit differences in strength and toughness. We have also endeavored to assess the mixed-mode fracture resistance, Gc, of silicon in a baseline EBC applied to SiCSiC CMC via four point bend test. These results are compared to previously determined properties of the comparable bulk material.

  4. Microbial production of polyhydroxybutyrate with tailor-made properties: an integrated modelling approach and experimental validation.

    Science.gov (United States)

    Penloglou, Giannis; Chatzidoukas, Christos; Kiparissides, Costas

    2012-01-01

    The microbial production of polyhydroxybutyrate (PHB) is a complex process in which the final quantity and quality of the PHB depend on a large number of process operating variables. Consequently, the design and optimal dynamic operation of a microbial process for the efficient production of PHB with tailor-made molecular properties is an extremely interesting problem. The present study investigates how key process operating variables (i.e., nutritional and aeration conditions) affect the biomass production rate and the PHB accumulation in the cells and its associated molecular weight distribution. A combined metabolic/polymerization/macroscopic modelling approach, relating the process performance and product quality with the process variables, was developed and validated using an extensive series of experiments and measurements. The model predicts the dynamic evolution of the biomass growth, the polymer accumulation, the consumption of carbon and nitrogen sources and the average molecular weights of the PHB in a bioreactor, under batch and fed-batch operating conditions. The proposed integrated model was used for the model-based optimization of the production of PHB with tailor-made molecular properties in Azohydromonas lata bacteria. The process optimization led to a high intracellular PHB accumulation (up to 95% g of PHB per g of DCW) and the production of different grades (i.e., different molecular weight distributions) of PHB. Copyright © 2011 Elsevier Inc. All rights reserved.

  5. Antioxidant, Anti-microbial Properties and Chemical Composition of Cumin Essential Oils Extracted by Three Methods

    Directory of Open Access Journals (Sweden)

    Fang Lianying

    2018-04-01

    Full Text Available The purpose of this study is to evaluate the chemical composition, antioxidant and anti-bacterial activity of cumin essential oils (CEOs extracted by different techniques, including supercritical carbon dioxide extraction (SCE, subcritical butane extraction (SBE and traditional solvent extraction (SE. Our results indicated that CEOs are a valuable source of bioactive compounds, including cumin aldehyde, γ-terpinene and β-pinene. The most abundant components found in CEOs obtained by SCE and SBE were similar, while the abundant components in SE, β-Cumic aldehyde (19.31% and α-phellandrene (9.49%, were distinctive. CEOs obtained by SCE exhibited higher antioxidant activity, followed by those extracted by SE and SBE. Moreover, the anti-microbial properties of CEOs obtained by SCE and SBE were higher than that of CEOs collected by SE. In conclusion, CEOs exhibit strong antioxidant and anti-microbial properties, which suggests a potential role of CEOs in preventing diseases associated with aging and oxidative stress, and our results highlight the potential usage of CEOs in the food industry.

  6. Barrier, structural and mechanical properties of bovine gelatin-chitosan blend films related to biopolymer interactions.

    Science.gov (United States)

    Benbettaïeb, Nasreddine; Kurek, Mia; Bornaz, Salwa; Debeaufort, Frédéric

    2014-09-01

    The increased use of synthetic packaging films has led to a high ecological problem due to their total non-biodegradability. Thus, there is a vital need to develop renewable and environmentally friendly bio-based polymeric materials. Films and coatings made from polysaccharide polymers, particularly chitosans and gelatins have good gas barrier properties and are envisaged more and more for applications in the biomedical and food fields, as well as for packaging. In this study a casting method was used to develop an edible plasticised film from chitosan and gelatin. Aiming to develop a blend film with enhanced properties, the effects of mixing chitosan (CS) and gelatin (G) in different proportions (CS:G, 75:25, 50:50, 25:75, w/w) on functional and physico-chemical properties have been studied. Mean film thickness increased linearly (R2 =0.999) with surface density of the film forming solution. An enhancement of mechanical properties by increasing the tensile strength (38.7±11 MPa for pure chitosan and 76.8±9 MPa for pure gelatin film) was also observed in blends, due to gelatin content.When the gelatin content in blend filmswas increased an improvement of both water vapour barrier properties [(4±0.3)×10(-10) g m(-1) s(-1) Pa(-1) for pure chitosan and (2.5±0.14)×10(-10) g m(-1) s(-1) Pa(-1) for pure gelatin, at 70% RH gradient] and oxygen barrier properties ((822.62±90.24)×10(-12) g m(-1) s(-1) Pa(-1) for blend film chitosan:gelatin (25:75 w/w) and (296.67±18.76)×10(-12) g m(-1) s(-1) Pa(-1) for pure gelatin was observed. Fourier transform infrared spectra of blend films showed a shift in the peak positions related to the amide groups (amide-I and amide-III) indicating interactions between biopolymers. Addition of gelatin in chitosan induced greater functional properties (mechanical, barrier) due to chemical interactions, suggesting an inter-penetrated network. © 2014 Society of Chemical Industry.

  7. Poly(3-hydroxybutyrate/ZnO Bionanocomposites with Improved Mechanical, Barrier and Antibacterial Properties

    Directory of Open Access Journals (Sweden)

    Ana M. Díez-Pascual

    2014-06-01

    Full Text Available Poly(3-hydroxybutyrate (PHB-based bionanocomposites incorporating different contents of ZnO nanoparticles were prepared via solution casting technique. The nanoparticles were dispersed within the biopolymer without the need for surfactants or coupling agents. The morphology, thermal, mechanical, barrier, migration and antibacterial properties of the nanocomposites were investigated. The nanoparticles acted as nucleating agents, increasing the crystallization temperature and the degree of crystallinity of the matrix, and as mass transport barriers, hindering the diffusion of volatiles generated during the decomposition process, leading to higher thermal stability. The Young’s modulus, tensile and impact strength of the biopolymer were enhanced by up to 43%, 32% and 26%, respectively, due to the strong matrix-nanofiller interfacial adhesion attained via hydrogen bonding interactions, as revealed by the FT-IR spectra. Moreover, the nanocomposites exhibited reduced water uptake and superior gas and vapour barrier properties compared to neat PHB. They also showed antibacterial activity against both Gram-positive and Gram-negative bacteria, which was progressively improved upon increasing ZnO concentration. The migration levels of PHB/ZnO composites in both non-polar and polar simulants decreased with increasing nanoparticle content, and were well below the current legislative limits for food packaging materials. These biodegradable nanocomposites show great potential as an alternative to synthetic plastic packaging materials especially for use in food and beverage containers and disposable applications.

  8. Study of the Properties of Bentonites for their use in Clay Geo synthetic Barriers

    International Nuclear Information System (INIS)

    Leiro Lopez, A.; Mateo Sanz, B.; Garcia Cidoncha, H.; Blanco Fernandez, M.

    2014-01-01

    Bentonites used for the production of clay geo synthetic barriers need to meet some properties so that they can be a waterproofing system. among the bentonites used in industry, sodium bentonite has the lowest permeability due to its high water absorption capacity in the inter-laminar space, causing it to swell and form a barrier to water flow. this paper provides the study of the properties of four bentonite to evaluate their quality the study of the properties of four bentonite to evaluate their quality. For this study, the main properties have been tested: water absorption, swelling index, fluid loss, cation exchange capacity and montmorillonite content. In order to optimize the procedure for the characterization of bentonites, correlations between different tests have been done, to identify the most suitable ones. Finally, a compatibility test has been carried out to study the performance of bentonites in water containing a high amount of sales, because in this case, an ion exchange between the interlayer sodium ions of bentonite and cations dissolved in the water can take, resulting in a decrease swell of the bentonite. (Author)

  9. Robust Superhydrophobic Graphene-Based Composite Coatings with Self-Cleaning and Corrosion Barrier Properties.

    Science.gov (United States)

    Nine, Md J; Cole, Martin A; Johnson, Lucas; Tran, Diana N H; Losic, Dusan

    2015-12-30

    Superhydrophobic surfaces for self-cleaning applications often suffer from mechanical instability and do not function well after abrasion/scratching. To address this problem, we present a method to prepare graphene-based superhydrophobic composite coatings with robust mechanical strength, self-cleaning, and barrier properties. A suspension has been formulated that contains a mixture of reduced graphene oxide (rGO) and diatomaceous earth (DE) modified with polydimethylsiloxane (PDMS) that can be applied on any surface using common coating methods such as spraying, brush painting, and dip coating. Inclusion of TiO2 nanoparticles to the formulation shows further increase in water contact angle (WCA) from 159 ± 2° to 170 ± 2° due to the structural improvement with hierarchical surface roughness. Mechanical stability and durability of the coatings has been achieved by using a commercial adhesive to bond the superhydrophobic "paint" to various substrates. Excellent retention of superhydrophobicity was observed even after sandpaper abrasion and crosscut scratching. A potentiodynamic polarization study revealed excellent corrosion resistance (96.78%) properties, and an acid was used to provide further insight into coating barrier properties. The ease of application and remarkable properties of this graphene-based composite coating show considerable potential for broad application as a self-cleaning and protective layer.

  10. Radionuclides distribution, properties, and microbial diversity of soils in uranium mill tailings from southeastern China

    International Nuclear Information System (INIS)

    Yan, Xun; Luo, Xuegang

    2015-01-01

    Objective: To collect the radioactive contamination data for environmental rehabilitation in uranium mill tailings in southeastern China. Method: The sample areas were divided into high, moderate and low concentration areas, according to the uranium concentration. For every area, 3 soil samples were collected at 0–15 cm, 15–30 cm and 30–45 cm depth respectively, with 5 repetitions for each. Total 45 (3 × 5 × 3) soil samples were collected. Physicochemical properties and enzyme activities of soils were determined as described by references. The concentrations of the radionuclides 238 U, 232 Th, 226 Ra and 40 K in soils were determined by using HPGe gamma-ray spectrometer. Soil microbial diversity was analyzed via denaturing gradient gel electrophoresis (DGGE). Results: Soil samples were all acidic. Physicochemical properties, like pH, content of total/available N, P and K, as well as enzyme activities were all increased along with decreased uranium concentration. The 232 Th concentration was increased with the decreased uranium concentration and was not influenced by the depth of sample sites. However, uranium concentration and depth of sample showed no significant influence on the concentrations of 226 Ra and 40 K. The concentration of 232 Th was significantly correlated with that of 226 Ra and 40 K, while the concentrations of 226 Ra and 40 K were significantly correlated. However, Pearson correlation coefficients between 238 U and other radionuclides were not significant. The microbial population in different concentration areas was different with four domain strains in low area, and two for both moderate and high areas. Furthermore, in each sample site, Proteobacteria was the most dominant flora, while environmental samples were the second according to GenBank database. Moreover, Serratia sp. of Proteobacteria was the dominant strain. Conclusion: Radionuclides distribution in the uranium mill tailing showed a profound influence on soil properties and

  11. Gamma irradiation effect on mechanical and barrier properties of foamed articles based on cassava starch

    International Nuclear Information System (INIS)

    Naime, Natalia; Ponce, Patricia; Lugao, Ademar B.

    2009-01-01

    With the increasing environmental concern, replacing the traditional non-biodegradable synthetic materials for biodegradable products is the challenge for many researchers and companies. Starch is considered one of the most promising natural polymers for packaging application because of its renewability, biodegradability and low cost. However, there are some limitations in developing starch-based products due to its poor mechanical properties and high moisture sensitivity. These properties can change when subjected to any process of sterilization, especially by gamma radiation. This work aims to study the mechanical and barrier properties of cassava starch in front of gamma radiation, for cobalt-60 ( 60 C0), when subjected to doses of 3 kGy, 6 kGy, 12 kGy and 25 kGy for the development of packaging, and then it compares the results to those of conventional packaging, as the expanded polystyrene (styrofoam) and paper cards. The starch foams (packaging) were obtained by thermopressing process. After baking, the foams were conditioned for one month at 23 deg C and 60% relative humidity (RH) before mechanical and barrier testing. Polyethyleneglycol (PEG 300) was selected as plasticizer. The packaging in which the cassava starch was subjected to irradiation had higher resistance to compression and higher flexibility compared to that in which the starch had not been irradiated. The expanded polystyrene and paper card packages are less resistant to compression than the cassava starch packages. The styrofoam is more flexible than the paper cards, which in turn is more flexible than packages of starch. After irradiation, the barrier properties of the foams were improved. (author)

  12. Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

    International Nuclear Information System (INIS)

    Kaeaeriaeinen, Tommi O.; Maydannik, Philipp; Cameron, David C.; Lahtinen, Kimmo; Johansson, Petri; Kuusipalo, Jurkka

    2011-01-01

    One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O 2 TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O 2 TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

  13. Atomic layer deposition on polymer based flexible packaging materials: Growth characteristics and diffusion barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Kaeaeriaeinen, Tommi O., E-mail: tommi.kaariainen@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Maydannik, Philipp, E-mail: philipp.maydannik@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Cameron, David C., E-mail: david.cameron@lut.f [ASTRaL, Lappeenranta University of Technology, Prikaatinkatu 3 E, 50100 Mikkeli (Finland); Lahtinen, Kimmo, E-mail: kimmo.lahtinen@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Johansson, Petri, E-mail: petri.johansson@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland); Kuusipalo, Jurkka, E-mail: jurkka.kuusipalo@tut.f [Tampere University of Technology, Paper Converting and Packaging Technology, P.O. Box 541, 33101 Tampere (Finland)

    2011-03-01

    One of the most promising areas for the industrial application of atomic layer deposition (ALD) is for gas barrier layers on polymers. In this work, a packaging material system with improved diffusion barrier properties has been developed and studied by applying ALD on flexible polymer based packaging materials. Nanometer scale metal oxide films have been applied to polymer-coated papers and their diffusion barrier properties have been studied by means of water vapor and oxygen transmission rates. The materials for the study were constructed in two stages: the paper was firstly extrusion coated with polymer film, which was then followed by the ALD deposition of oxide layer. The polymers used as extrusion coatings were polypropylene, low and high density polyethylene, polylactide and polyethylene terephthalate. Water vapor transmission rates (WVTRs) were measured according to method SCAN-P 22:68 and oxygen transmission rates (O{sub 2}TRs) according to a standard ASTM D 3985. According to the results a 10 nm oxide layer already decreased the oxygen transmission by a factor of 10 compared to uncoated material. WVTR with 40 nm ALD layer was better than the level currently required for most common dry flexible packaging applications. When the oxide layer thickness was increased to 100 nm and above, the measured WVTRs were limited by the measurement set up. Using an ALD layer allowed the polymer thickness on flexible packaging materials to be reduced. Once the ALD layer was 40 nm thick, WVTRs and O{sub 2}TRs were no longer dependent on polymer layer thickness. Thus, nanometer scale ALD oxide layers have shown their feasibility as high quality diffusion barriers on flexible packaging materials.

  14. Visualization of physico-chemical properties and microbial distribution in soil and root microenvironments

    Science.gov (United States)

    Eickhorst, Thilo; Schmidt, Hannes

    2016-04-01

    Plant root development is influenced by soil properties and environmental factors. In turn plant roots can also change the physico-chemical conditions in soil resulting in gradients between roots and the root-free bulk soil. By releasing a variety of substances roots facilitate microbial activities in their direct vicinity, the rhizosphere. The related microorganisms are relevant for various ecosystem functions in the root-soil interface such as nutrient cycling. It is therefore important to study the impact and dynamics of microorganisms associated to different compartments in root-soil interfaces on a biologically meaningful micro-scale. The analysis of microorganisms in their habitats requires microscopic observations of the respective microenvironment. This can be obtained by preserving the complex soil structure including the root system by resin impregnation resulting in high quality thin sections. The observation of such sections via fluorescence microscopy, SEM-EDS, and Nano-SIMS will be highlighted in this presentation. In addition, we will discuss the combination of this methodological approach with other imaging techniques such as planar optodes or non-invasive 3D X-ray CT to reveal the entire spatial structure and arrangement of soil particles and roots. When combining the preservation of soil structure via resin impregnation with 16S rRNA targeted fluorescence in situ hybridization (FISH) single microbial cells can be visualized, localized, and quantified in the undisturbed soil matrix including the root-soil interfaces. The simultaneous use of multiple oligonucleotide probes thereby provides information on the spatial distribution of microorganisms belonging to different phylogenetic groups. Results will be shown for paddy soils, where management induced physico-chemical dynamics (flooding and drying) as well as resulting microbial dynamics were visualized via correlative microscopy in resin impregnated samples.

  15. Evaluation of properties and thermal stress field for thermal barrier coatings

    Institute of Scientific and Technical Information of China (English)

    王良; 齐红宇; 杨晓光; 李旭

    2008-01-01

    In order to get thermal stress field of the hot section with thermal barrier coating (TBCs), the thermal conductivity and elastic modulus of top-coat are the physical key properties. The porosity of top-coat was tested and evaluated under different high temperatures. The relationship between the microstructure (porosity of top-coat) and properties of TBCs were analyzed to predict the thermal properties of ceramic top-coat, such as thermal conductivity and elastic modulus. The temperature and stress field of the vane with TBCs were simulated using two sets of thermal conductivity data and elastic modulus, which are from literatures and this work, respectively. The results show that the temperature and stress distributions change with thermal conductivity and elastic modulus. The differences of maximum temperatures and stress are 6.5% and 8.0%, respectively.

  16. Long-Term Coffee Monoculture Alters Soil Chemical Properties and Microbial Communities.

    Science.gov (United States)

    Zhao, Qingyun; Xiong, Wu; Xing, Yizhang; Sun, Yan; Lin, Xingjun; Dong, Yunping

    2018-04-17

    Long-term monoculture severely inhibits coffee plant growth, decreases its yield and results in serious economic losses in China. Here, we selected four replanted coffee fields with 4, 18, 26 and 57 years of monoculture history in Hainan China to investigate the influence of continuous cropping on soil chemical properties and microbial communities. Results showed long-term monoculture decreased soil pH and organic matter content and increased soil EC. Soil bacterial and fungal richness decreased with continuous coffee cropping. Principal coordinate analysis suggested monoculture time was a major determinant of bacterial and fungal community structures. Relative abundances of bacterial Proteobacteria, Bacteroidetes and Nitrospira and fungal Ascomycota phyla decreased over time. At genus level, potentially beneficial microbes such as Nitrospira and Trichoderma, significantly declined over time and showed positive relationships with coffee plant growth in pots. In conclusion, continuous coffee cropping decreased soil pH, organic matter content, potentially beneficial microbes and increased soil EC, which might lead to the poor growth of coffee plants in pots and decline of coffee yields in fields. Thus, developing sustainable agriculture to improve soil pH, organic matter content, microbial activity and reduce the salt stress under continuous cropping system is important for coffee production in China.

  17. Changes in Microbial Community Structure and Soil Biological Properties in Mined Dune Areas During Re-vegetation.

    Science.gov (United States)

    Escobar, Indra Elena C; Santos, Vilma M; da Silva, Danielle Karla A; Fernandes, Marcelo F; Cavalcante, Uided Maaze T; Maia, Leonor C

    2015-06-01

    The aim of this study was to describe the impact of re-vegetation on the restoration of microbial community structure and soil microbiological properties in sand dunes that had been affected by mining activity. Soil samples were collected during the dry and rainy seasons from a chronosequence (1, 9, 21 years) of re-vegetated dunes using a single preserved dune as a reference. The composition of the fatty acid methyl esters and soil microbial properties were evaluated. The results showed that the changes in microbial community structure were related to seasonal variations: biomarkers of Gram-positive bacteria were higher than Gram-negative bacteria during the dry season, showing that this group of organisms is more tolerant to these stressful conditions. The microbial community structure in the natural dune was less affected by seasonal variation compared to the re-vegetated areas, whereas the opposite was observed for microbiological properties. Thus, in general, the proportion of saprobic fungi was higher in the natural dune, whereas Gram-negative bacteria were proportionally more common in the younger areas. Although over time the re-vegetation allows the recovery of the microbial community and the soil functions, these communities and functions are different from those found in the undisturbed areas.

  18. Preparation of pectin/silver nanoparticles composite films with UV-light barrier and properties.

    Science.gov (United States)

    Shankar, Shiv; Tanomrod, Nattareya; Rawdkuen, Saroat; Rhim, Jong-Whan

    2016-11-01

    Silver nanoparticles (AgNPs) was synthesized by a green method using an aqueous extract of Caesalpinia mimosoides Lamk (CMLE) as reducing and stabilizing agents, and they were used for the preparation of pectin-based antimicrobial composite films. The AgNPs were spherical in shape with the size in the range of 20-80nm and showed the absorption peak around 500nm. The pectin/AgNPs composite film exhibited characteristic absorption peak of AgNPs at 480nm. The surface color and light transmittance of the pectin films were greatly influenced by the addition of AgNPs. The lightness of the films decreased, however, redness and yellowness of the films increased after incorporation of AgNPs. UV-light barrier property of the pectin film increased significantly with a little decrease in the transparency. Though there were no structural changes in the pectin film by the incorporation of CMLE and AgNPs as indicated by the FTIR results, the film properties such as thermal stability, mechanical strength, and water vapor barrier properties of the pectin films increased. The pectin/AgNPs nanocomposite films exhibited strong antibacterial activity against food-borne pathogenic bacteria, Escherichia coli and Listeria monocytogenes. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. Morphology, thermal, mechanical, and barrier properties of graphene oxide/poly(lactic acid) nanocomposite films

    International Nuclear Information System (INIS)

    Kim, Seong Woo; Choi, Hyun Muk

    2016-01-01

    To improve the physical and gas barrier properties of biodegradable poly(lactic acid) (PLA) film, two graphene nanosheets of highly functionalized graphene oxide (0.3 wt% to 0.7 wt%) and low-functionalized graphene oxide (0.5 wt%) were incorporated into PLA resin via solution blending method. Subsequently, we investigated the effects of material parameters such as loading level and degree of functionalization for the graphene nanosheets on the morphology and properties of the resultant nanocomposites. The highly functionalized graphene oxide (GO) caused more exfoliation and homogeneous dispersion in PLA matrix as well as more sustainable suspensions in THF, compared to low-functionalized graphene oxide (LFGO). When loaded with GO from 0.3 wt% to 0.7 wt%, the glass transition temperature, degree of crystallinity, tensile strength and modulus increased steadily. The GO gave rise to more pronounced effect in the thermal and mechanical reinforcement, relative to LFGO. In addition, the preparation of fairly transparent PLA-based nanocomposite film with noticeably improved barrier performance achieved only when incorporated with GO up to 0.7wt%. As a result, GO may be more compatible with hydrophilic PLA resin, compared to LFGO, resulting in more prominent enhancement of nanocomposites properties.

  20. Transparent nanocellulosic multilayer thin films on polylactic acid with tunable gas barrier properties.

    Science.gov (United States)

    Aulin, Christian; Karabulut, Erdem; Tran, Amy; Wågberg, Lars; Lindström, Tom

    2013-08-14

    The layer-by-layer (LbL) deposition method was used for the build-up of alternating layers of nanofibrillated cellulose (NFC) or carboxymethyl cellulose (CMC) with a branched, cationic polyelectrolyte, polyethyleneimine (PEI) on flexible poly (lactic acid) (PLA) substrates. With this procedure, optically transparent nanocellulosic films with tunable gas barrier properties were formed. 50 layer pairs of PEI/NFC and PEI/CMC deposited on PLA have oxygen permeabilities of 0.34 and 0.71 cm(3)·μm/m(2)·day·kPa at 23 °C and 50% relative humidity, respectively, which is in the same range as polyvinyl alcohol and ethylene vinyl alcohol. The oxygen permeability of these multilayer nanocomposites outperforms those of pure NFC films prepared by solvent-casting. The nanocellulosic LbL assemblies on PLA substrates was in detailed characterized using a quartz crystal microbalance with dissipation (QCM-D). Atomic force microscopy (AFM) reveals large structural differences between the PEI/NFC and the PEI/CMC assemblies, with the PEI/NFC assembly showing a highly entangled network of nanofibrils, whereas the PEI/CMC surfaces lacked structural features. Scanning electron microscopy images showed a nearly perfect uniformity of the nanocellulosic coatings on PLA, and light transmittance results revealed remarkable transparency of the LbL-coated PLA films. The present work demonstrates the first ever LbL films based on high aspect ratio, water-dispersible nanofibrillated cellulose, and water-soluble carboxymethyl cellulose polymers that can be used as multifunctional films and coatings with tailorable properties, such as gas barriers and transparency. Owing to its flexibility, transparency and high-performance gas barrier properties, these thin film assemblies are promising candidates for several large-scale applications, including flexible electronics and renewable packaging.

  1. Nonlinear properties of double and triple barrier resonant tunneling structures in the sub-THz range

    International Nuclear Information System (INIS)

    Karuzskij, A.L.; Perestoronin, A.V.; Volchkov, N.A.

    2012-01-01

    The high-frequency nonlinear properties of GaAs/AlAs resonant tunneling diode (RTD) nanostructures and perspectives of implementation of the quantum regime of amplification in such structures, which is especially efficient in the range of sub-THz and THz ranges, are investigated. It is shown that in a triple barrier RTD the symmetry between the processes of amplification and dissipation can be avoided because of the interaction of an electromagnetic wave with both of resonant states in two quantum wells, that results in the significant growth of an RTD efficiency [ru

  2. Microbial utilization of low molecular weight organics in soil depends on the substances properties

    Science.gov (United States)

    Gunina, Anna

    2016-04-01

    Utilization of low molecular weight organic substances (LMWOS) in soil is regulated by microbial uptake from solution and following incorporation of into specific cell cycles. Various chemical properties of LMWOS, namely oxidation state, number of carbon (C) atoms, number of carboxylic (-COOH) groups, can affect their uptake from soil solution and further microbial utilization. The aim of the study was to trace the initial fate (including the uptake from soil solution and utilization by microorganisms) of three main classes of LMWOS, having contrast properties - sugars, carboxylic and amino acids. Top 10 cm of mineral soil were collected under Silver birch stands within the Bangor DIVERSE experiment, UK. Soil solution was extracted by centrifugation at 4000 rpm during 15 min. Soil was spiked with 14C glucose or fructose; malic, succinic or formic acids; alanine or glycine. No additional non-labeled LMWOS were added. 14C was traced in the dissolved organic matter (DOM), CO2, cytosol and soil organic matter (SOM) during one day. To estimate half-life times (T1 /2)of LMWOS in soil solution and in SOM pools, the single and double first order kinetic equations were fitted to the uptake and mineralization dynamics, respectively. The LMWOS T1 /2in DOM pool varied between 0.6-5 min, with the highest T1 /2for sugars (3.7 min) and the lowest for carboxylic acids (0.6-1.4 min). Thus, initial uptake of LMWOS is not a limiting step of microbial utilization. The T1 /2 of carboxylic and amino acids in DOM were closely related with oxidation state, showing that reduced substances remain in soil solution longer, than oxidized. The initial T1 /2 of LMWOS in SOM ranged between 30-80 min, with the longest T1 /2 for amino acids (50-80 min) and the shortest for carboxylic acids (30-48 min). These T1 /2values were in one-two orders of magnitude higher than LMWOS T1 /2 in soil solution, pointing that LMWOS mineralization occur with a delay after the uptake. Absence of correlations between

  3. Effect of barrier layers on the properties of indium tin oxide thin films on soda lime glass substrates

    International Nuclear Information System (INIS)

    Lee, Jung-Min; Choi, Byung-Hyun; Ji, Mi-Jung; An, Yong-Tae; Park, Jung-Ho; Kwon, Jae-Hong; Ju, Byeong-Kwon

    2009-01-01

    In this paper, the electrical, structural and optical properties of indium tin oxide (ITO) films deposited on soda lime glass (SLG) haven been investigated, along with high strain point glass (HSPG) substrate, through radio frequency magnetron sputtering using a ceramic target (In 2 O 3 :SnO 2 , 90:10 wt.%). The ITO films deposited on the SLG show a high electrical resistivity and structural defects compared with those deposited on HSPG due to the Na ions from the SLG diffusing to the ITO film by annealing. However, these properties can be improved by intercalating a barrier layer of SiO 2 or Al 2 O 3 between the ITO film and the SLG substrate. SIMS analysis has confirmed that the barrier layer inhibits the Na ion's diffusion from the SLG. In particular, the ITO films deposited on the Al 2 O 3 barrier layer, show better properties than those deposited on the SiO 2 barrier layer.

  4. Acoustic and Electrical Property Changes Due to Microbial Growth and Biofilm Formation in Porous Media

    Science.gov (United States)

    A laboratory study was conducted to investigate the effect of microbial growth and biofilm formation on compressional waves, and complex conductivity during stimulated microbial growth. Over the 29 day duration of the experiment, compressional wave amplitudes and arrival times f...

  5. Physicochemical, microbial, and sensory properties of nanopowdered eggshell-supplemented yogurt during storage.

    Science.gov (United States)

    Al Mijan, Mohammad; Choi, Kyung-Hoon; Kwak, Hae-Soo

    2014-01-01

    This study was carried out to investigate the possibility of adding nanopowdered eggshell (NPES) into yogurt to improve the functionality of yogurt and the effects of adding NPES on the physicochemical, microbial, and sensory properties of the products during storage. The pH and mean lactic acid bacteria counts of NPES-added (0.15-0.45%, wt/vol) yogurt ranged from 4.31 to 4.66 and from 6.56 × 10(8) to 8.56 × 10(8)cfu/mL, respectively, whereas these values ranged from 4.13 to 4.44 and 8.46 × 10(8) to 1.39 × 10(9), respectively, for the control samples during storage at 5 °C for 16d, which indicates a prolonged shelf-life with NPES-supplemented yogurt. Color analysis showed that the lightness (L*) and position between red and green (a*) values were not significantly influenced by the addition of NPES. However, the position between yellow and blue (b*) value significantly increased with the addition of the concentration (0.45%, wt/vol) of NPES at d 16 of storage. Sensory evaluation revealed that NPES-added yogurts showed a notably less sourness score and a higher astringency score than the control. An earthy flavor was higher in 0.45% NPES-supplemented yogurt compared with the control. Based on the results obtained from the current study, the concentration (0.15 to 0.30%, wt/vol) of NPES can be used to formulate NPES-supplemented yogurt without any significant adverse effects on the physicochemical, microbial, and sensory properties. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  6. Influence of dielectric barrier discharge treatment on mechanical and dyeing properties of wool

    Science.gov (United States)

    Rahul, NAVIK; Sameera, SHAFI; Md Miskatul, ALAM; Md Amjad, FAROOQ; Lina, LIN; Yingjie, CAI

    2018-06-01

    Physical and chemical properties of wool surface significantly affect the absorbency, rate of dye bath exhaustion and fixation of the industrial dyes. Hence, surface modification is a necessary operation prior to coloration process in wool wet processing industries. Plasma treatment is an effective alternative for physiochemical modification of wool surface. However, optimum processing parameters to get the expected modification are still under investigation, hence this technology is still under development in the wool wet processing industries. Therefore, in this paper, treatment parameters with the help of simple dielectric barrier discharge plasma reactor and air as a plasma gas, which could be a promising combination for treatment of wool substrate at industrial scale were schematically studied, and their influence on the water absorbency, mechanical, and dyeing properties of twill woven wool fabric samples are reported. It is expected that the results will assist to the wool coloration industries to improve the dyeing processes.

  7. Enhancement of Gas Barrier Properties of CFRP Laminates Fabricated Using Thin-Ply Prepregs

    Science.gov (United States)

    横関, 智弘; 高木, 智宏; 吉村, 彰記; Ogasawara, Toshio; 荻原, 慎二

    Composite laminates manufactured using thin-ply prepregs are expected to have superior resistance properties against microcracking compared to those using standard prepregs. In this study, comparative investigations are presented on the microcrack accumulation and gas leakage characteristics of CFRP laminates fabricated using standard and thin-ply prepregs, consisting of high-performance carbon fiber and toughened epoxy, as a fundamental research on the cryogenic composite tanks for future space vehicles. It was shown that laminates using thin-ply prepregs exhibited much higher strain at microcrack initiation compared to those using standard prepregs at room and cryogenic temperatures. In addition, helium gas leak tests using CFRP laminated tubular specimens subjected to quasi-static tension loadings were performed. It was demonstrated that CFRP laminates using thin-ply prepregs have higher gas barrier properties than those using standard prepregs.

  8. Morphological, mechanical, barrier and properties of films based on acetylated starch and cellulose from barley.

    Science.gov (United States)

    El Halal, Shanise Lisie Mello; Colussi, Rosana; Biduski, Bárbara; Evangelho, Jarine Amaral do; Bruni, Graziella Pinheiro; Antunes, Mariana Dias; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2017-01-01

    Biodegradable films of native or acetylated starches with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. The tensile strength of the acetylated starch film was lower than those of the native starch film, without fibers. The addition of fibers increased the tensile strength and decreased the elongation and the moisture of native and acetylated starches films. The acetylated starch film showed higher water solubility when compared to native starch film. The addition of cellulose fibers reduced the water solubility of the acetylated starch film. The films reinforced with cellulose fiber exhibited a higher initial decomposition temperature and thermal stability. The mechanical, barrier, solubility, and thermal properties are factors which direct the type of the film application in packaging for food products. The films elaborated with acetylated starches of low degree of substitution were not effective in a reduction of the water vapor permeability. The addition of the cellulose fiber in acetylated and native starches films can contribute to the development of more resistant films to be applied in food systems that need to maintain their integrity. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  9. Mechanical and water barrier properties of agar/κ-carrageenan/konjac glucomannan ternary blend biohydrogel films.

    Science.gov (United States)

    Rhim, Jong-Whan; Wang, Long-Feng

    2013-07-01

    Multicomponent hydrogel films composed of agar, κ-carrageenan, konjac glucomannan powder, and nanoclay (Cloisite(®) 30B) were prepared and their mechanical and water barrier properties such as water vapor permeability (WVP), water contact angle (CA), water solubility (WS), water uptake ratio (WUR), water vapor uptake ratio (WVUR) were determined. Mechanical, water vapor barrier, and water resistance properties of the ternary blend film exhibited middle range of individual component films, however, they increased significantly after formation of nanocomposite with the clay. Especially, the water holding capacity of the ternary blend biopolymer films increased tremendously, from 800% to 1681% of WUR for agar and κ-carrageenan films up to 5118% and 5488% of WUR for the ternary blend and ternary blend nanocomposite films, respectively. Water vapor adsorption behavior of films was also tested by water vapor adsorption kinetics and water vapor adsorption isotherms test. Preliminary test result for fresh spinach packaging revealed that the ternary blend biohydrogel films had a high potential for the use as an antifogging film for packaging highly respiring agricultural produce. In addition, the ternary blend nanocomposite film showed an antimicrobial activity against Gram-positive bacteria, Listeria monocytogenes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Hemicelluloses/montmorillonite hybrid films with improved mechanical and barrier properties

    Science.gov (United States)

    Chen, Ge-Gu; Qi, Xian-Ming; Li, Ming-Peng; Guan, Ying; Bian, Jing; Peng, Feng; Yao, Chun-Li; Sun, Run-Cang

    2015-11-01

    A facile and environmentally friendly method was introduced to incorporate montmorillonite (MMT) as an inorganic phase into quaternized hemicelluloses (QH) for forming hemicellulose-based films. Two fillers, polyvinyl alcohol (PVA) and chitin nanowhiskers (NCH), were added into the hemicelluloses/MMT hybrid matrices to prepare hybrid films, respectively. The hybrid films were nanocomposites with nacre-like structure and multifunctional characteristics including higher strength and good oxygen barrier properties via the electrostatic and hydrogen bonding interactions. The addition of PVA and NCH could induce changes in surface topography, and effectively enhance mechanical strength, thermal stability, transparency, and oxygen barrier properties. The tensile strengths of the composite films FPVA(0.3), FPVA(0.5), and FNCH(0.8) were 53.7, 46.3, and 50.1 MPa, respectively, which were 171%, 134%, and 153% larger than the FQH-MMT film (19.8 MPa). The tensile strength, and oxygen transmission rate of QH-MMT-PVA film were better than those of quaternized hemicelluloses/MMT films. Thus, the proper filler is very important for the strength of the hybrid film. These results provide insights into the understanding of the structural relationships of hemicellulose-based composite films in coating and packaging application for the future.

  11. Nagra technical report 14-02, Geological basics - Dossier VI - Barrier properties of proposed host rock sediments and neighbouring rock

    International Nuclear Information System (INIS)

    Gautschi, A.; Deplazes, G.; Traber, D.; Marschall, P.; Mazurek, M.; Gimmi, T.; Maeder, U.

    2014-01-01

    This dossier is the sixth of a series of eight reports concerning the safety and technical aspects of locations for the disposal of radioactive wastes in Switzerland. It discusses the barrier properties of the proposed host rock sediments and neighbouring rock layers. The mineralogical composition of the host rocks are discussed as are their pore densities and hydrological properties. Diffusion aspects are discussed. The aquifer systems in the proposed depository areas and their classification are looked at. The barrier properties of the host rocks and those of neighbouring sediments are discussed. Finally, modelling concepts and parameters for the transport of radionuclides in the rocks are discussed

  12. Microbial Diversity and Mineralogical-Mechanical Properties of Calcitic Cave Speleothems in Natural and in Vitro Biomineralization Conditions

    Directory of Open Access Journals (Sweden)

    Navdeep K. Dhami

    2018-02-01

    Full Text Available Natural mineral formations are a window into important processes leading to carbon storage and mineralized carbonate structures formed through abiotic and biotic processes. In the current study, we made an attempt to undertake a comprehensive approach to characterize the mineralogical, mechanical, and microbial properties of different kinds of speleothems from karstic caves; with an aim to understand the bio-geo-chemical processes in speleothem structures and their impact on nanomechanical properties. We also investigated the biomineralization abilities of speleothem surface associated microbial communities in vitro. Mineralogical profiling using techniques such as X-ray powder Diffraction (XRD and Tescan Integrated Mineral Analyzer (TIMA demonstrated that calcite was the dominant mineral in the majority of speleothems with Energy Dispersive X-ray Analysis (EDS indicating a few variations in the elemental components. Differing proportions of polymorphs of calcium carbonate such as aragonite and vaterite were also recorded. Significant variations in trace metal content were recorded through Inductively Coupled Plasma Mass Spectrometer (ICP-MS. Scanning Electron Microscopy (SEM analysis revealed differences in morphological features of the crystals which varied from triangular prismatic shapes to etched spiky forms. Microbial imprints and associations were seen in a few sections. Analysis of the associated microbial diversity showed significant differences between various speleothems at Phylum level; although Proteobacteria and Actinobacteria were found to be the predominant groups. Genus level microbial associations showed a relationship with the geochemistry, mineralogical composition, and metal content of the speleothems. The assessment of nanomechanical properties measured by Nanoindentation revealed that the speleothems with a dominance of calcite were stronger than the speleothems with mixed calcium carbonate polymorphs and silica content

  13. Antimicrobial, Physicochemical, Mechanical, and Barrier Properties of Tapioca Starch Films Incorporated with Eucalyptus Extract

    Directory of Open Access Journals (Sweden)

    M. Rojhan

    2013-11-01

    Full Text Available Starch is found in abundance in nature and it is one of the raw materials used for food packagingbecause of the low price, biodegradability, good mechanical and barrier properties. The recycling ability ofcoating materials was significantly increased by using edible films and coating in comparison to traditionalpackaging and it could be an alternative for synthetic films. In this research, the effect of eucalyptus extract(Aqueous Extract was investigated on tapioca starch films. Tapioca starch films were prepared by castingmethod with addition of eucalyptus extract and a mixture of sorbitol/glycerol (weight ratio of 3 to 1 asplasticizers. Eucalyptus extract incorporated to the tapioca starch films were dried at different concentrations(0, 15, 25, and 35 of total solid under controlled conditions. Physicochemical properties such as waterabsorption capacity (WAC, water vapor permeability (WVP and mechanical properties of the films wereevaluated. Results showed that by increasing the concentration of eucalyptus extract, tensile strength wasincreased from 20.60 to 15.68 (MPa, also elongation was increased from 19.31 to 23.57 (% at break andYoung’s modulus was decreased from 800.31 to 500.32 (MPa. Also incorporation of eucalyptus extract in thestructure of biopolymer increased permeability of water vapor of starch films. Tapioca starch filmsincorporated with eucalyptus extract exhibited excellent antimicrobial activity against E. Coli. In summary,eucalyptus extract improves functional properties of tapioca starch films and this types of films can be used infood packaging.

  14. Inferred effects of cloud deposition on forest floor nutrient cycling and microbial properties along a short elevation gradient

    International Nuclear Information System (INIS)

    Lavoie, M.; Bradley, R.L.

    2003-01-01

    Higher cloud cover significantly decreases forest floor pH, decrease exchangeable cations, modifies mineral-N speciation and increases physiological stress within microbial communities. - Cloud water deposition often increases with elevation, and it is widely accepted that this cloud water increases acid loading to upland forest ecosystems. A study was undertaken in south-eastern Quebec to determine if a 250 m elevation gradient (i.e. 420-665 m), along a uniform sugar-maple stand on the slope of Mount Orford, corresponded to a pH gradient in the forest floor and to predictable changes in soil nutrient availability and microbial properties. Precipitation data from a nearby study, and a photographic survey, provided presumptive evidence that this elevation gradient corresponded to a strong gradient in cloud water deposition. Forest floor temperature did not differ significantly across elevations. Forest floor moisture content was significantly higher, whereas pH and exchangeable Ca and Mg were significantly lower, at the higher elevations. Average seasonal net nitrification rates, determined by long-term laboratory incubations, did not differ significantly across elevations, whereas average seasonal net ammonification rates were significantly higher at higher elevations. Basal respiration rates and microbial biomass did not differ significantly across elevations, but metabolic quotient was significantly higher at higher elevations indicating possible environmental stress on forest floor microbial communities due to cloud water deposition. Anaerobic N mineralisation rates were significantly higher at higher elevations suggesting that N-limited microbial communities frequently exposed to cloud cover can be important short-term sinks for atmospheric N, thereby contributing to increase the active-N fraction of forest floors. We conclude that, where no significant changes in vegetation or temperature occur, elevation gradients can still be used to understand the spatial

  15. Influence of supplementary cementitious materials on the properties of concrete for secondary protection barrier in radioactive waste repositories

    Czech Academy of Sciences Publication Activity Database

    Koťátková, J.; Čáchová, M.; Bezdička, Petr; Vejmelková, E.; Konvalinka, P.; Zemanová, L.; Černý, R.

    2018-01-01

    Roč. 760, SI (2018), s. 96-101 ISSN 1662-9795. [Special Concrete and Composites 2017 /14./. Lísek, 10.10.2017-11.10.2017] R&D Projects: GA ČR(CZ) GA17-11635S Institutional support: RVO:61388980 Keywords : Basic physical properties * Mechanical properties * Repository * Secondary protection barrier * Supplementary cementitious materials * Thermal properties Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry

  16. Spatial heterogeneity of physicochemical properties explains differences in microbial composition in arid soils from Cuatro Cienegas, Mexico

    Directory of Open Access Journals (Sweden)

    Silvia Pajares

    2016-09-01

    Full Text Available Arid ecosystems are characterized by high spatial heterogeneity, and the variation among vegetation patches is a clear example. Soil biotic and abiotic factors associated with these patches have also been well documented as highly heterogeneous in space. Given the low vegetation cover and little precipitation in arid ecosystems, soil microorganisms are the main drivers of nutrient cycling. Nonetheless, little is known about the spatial distribution of microorganisms and the relationship that their diversity holds with nutrients and other physicochemical gradients in arid soils. In this study, we evaluated the spatial variability of soil microbial diversity and chemical parameters (nutrients and ion content at local scale (meters occurring in a gypsum-based desert soil, to gain knowledge on what soil abiotic factors control the distribution of microbes in arid ecosystems. We analyzed 32 soil samples within a 64 m2 plot and: (a characterized microbial diversity using T-RFLPs of the bacterial 16S rRNA gene, (b determined soil chemical parameters, and (c identified relationships between microbial diversity and chemical properties. Overall, we found a strong correlation between microbial composition heterogeneity and spatial variation of cations (Ca2, K+ and anions (HCO ${}_{3}^{-}$ 3 − , Cl−, SO ${}_{4}^{2-}$ 4 2 − content in this small plot. Our results could be attributable to spatial differences of soil saline content, favoring the patchy emergence of salt and soil microbial communities.

  17. Microbial mat of the thermal springs Kuchiger Republic of Buryatia: species composition, biochemical properties and electrogenic activity in biofuel cell

    Science.gov (United States)

    Aleksandrovich Yuriev, Denis; Viktorovna Zaitseva, Svetlana; Olegovna Zhdanova, Galina; Yurievich Tolstoy, Mikhail; Dondokovna Barkhutova, Darima; Feodorovna Vyatchina, Olga; Yuryevna Konovalova, Elena; Iosifovich Stom, Devard

    2018-02-01

    Electrogenic, molecular and some other properties of a microbial mat isolated from the Kuchiger hot spring (Kurumkansky District, Republic of Buryatia) were studied. Molecular analysis showed that representatives of Proteobacteria (85.5 % of the number of classified bacterial sequences) prevailed in the microbial mat of the Kuchiger springs, among which sulfur bacteria of the genus Thiothrix were the most numerous. In the microbial mat there were bacteria from the families Rhodocyclaceae, Comamonadaceae and Flavobacteriaceae. Phylum Bacteroidetes, Cyanobacteria/Chloroplast, Fusobacteria, Fibrobacteres, Acidobacteria, Chlorobi, Spirochaetes, Verrucomicrobia, Firmicutes, Deinococcus-Thermus, Chloroflexi and Actinobacteria are also noted in the composition of the microbial mat. Under the experimental conditions using Kuchiger-mat 16 as bioagents, glucose and peptone as substrates, the power of BFC was 240 and 221 mW / m2, respectively. When replacing the substrate with sodium acetate, the efficiency of the BFC was reduced by a factor of 10 (20 mW / m2). The prospects of using a microbial mat “Kuchiger-16” as an electrogen in BFC when utilizing alkaline waste water components to generate electricity are discussed.

  18. Mechanical, barrier and morphological properties of starch nanocrystals-reinforced pea starch films.

    Science.gov (United States)

    Li, Xiaojing; Qiu, Chao; Ji, Na; Sun, Cuixia; Xiong, Liu; Sun, Qingjie

    2015-05-05

    To characterize the pea starch films reinforced with waxy maize starch nanocrystals, the mechanical, water vapor barrier and morphological properties of the composite films were investigated. The addition of starch nanocrystals increased the tensile strength of the composite films, and the value of tensile strength of the composite films was highest when starch nanocrystals content was 5% (w/w). The moisture content (%), water vapor permeability, and water-vapor transmission rate of the composite films significantly decreased as starch nanocrystals content increased. When their starch nanocrystals content was 1-5%, the starch nanocrystals dispersed homogeneously in the composite films, resulting in a relatively smooth and compact film surface and better thermal stability. However, when starch nanocrystals content was more than 7%, the starch nanocrystals began to aggregate, which resulted in the surface of the composite films developing a longitudinal fibrous structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Skin barrier properties in patients with recessive X-linked ichthyosis

    DEFF Research Database (Denmark)

    Johansen, J D; Ramsing, D; Vejlsgaard, G

    1995-01-01

    increased in controls compared to ichthyosis patients, when evaluated by TEWL. When evaluated by erythema index a statistically significant increase in redness was found in controls, but not in ichthyosis patients. Electrical capacitance, reflecting skin hydration, was significantly reduced in RXLI patients......Patients with X-linked recessive ichthyosis (RXLI) were studied as a model of the effect of disturbed epidermal lipid composition on skin barrier function. Thirteen patients with RXLI and 15 age- and sex-matched controls were patch-tested with sodium lauryl sulphate (SLS) 0.5% for 24 h. Basal skin...... properties and skin response to SLS were studied by measurement of transepidermal water loss (TEWL), electrical capacitance and erythema index. No statistically significant difference in basal TEWL was found between the two groups. The skin response to SLS was found to be statistically significantly...

  20. Transparent films based on PLA and montmorillonite with tunable oxygen barrier properties

    DEFF Research Database (Denmark)

    Svagan, Anna; Åkesson, Anna; Cárdenas, Marité

    2012-01-01

    Polylactide (PLA) is viewed as a potential material to replace synthetic plastics (e.g., poly(ethylene terephthalate) (PET)) in food packaging, and there have been a number of developments in this direction. However, for PLA to be competitive in more demanding uses such as the packaging of oxygen......-sensitive foods, the oxygen permeability coefficient (OP) needs to be reduced by a factor of ∼10. To achieve this, a layer-by-layer (Lbl) approach was used to assemble alternating layers of montmorillonite clay and chitosan on extruded PLA film surfaces. When 70 bilayers were applied, the OP was reduced by 99...... and 96%, respectively, at 20 and 50% RH. These are, to our knowledge, the best improvements in oxygen barrier properties ever reported for a PLA/clay-based film. The process of assembling such multilayer structures was characterized using a quartz crystal microbalance with dissipation monitoring...

  1. Fine-tuning the physicochemical properties of peptide-based blood-brain barrier shuttles.

    Science.gov (United States)

    Ghasemy, Somaye; García-Pindado, Júlia; Aboutalebi, Fatemeh; Dormiani, Kianoush; Teixidó, Meritxell; Malakoutikhah, Morteza

    2018-05-01

    N-methylation is a powerful method to modify the physicochemical properties of peptides. We previously found that a fully N-methylated tetrapeptide, Ac-(N-MePhe) 4 -CONH 2 , was more lipophilic than its non-methylated analog Ac-(Phe) 4 -CONH 2 . In addition, the former crossed artificial and cell membranes while the latter did not. Here we sought to optimize the physicochemical properties of peptides and address how the number and position of N-methylated amino acids affect these properties. To this end, 15 analogs of Ac-(Phe) 4 -CONH 2 were designed and synthesized in solid-phase. The solubility of the peptides in water and their lipophilicity, as measured by ultra performance liquid chromatography (UPLC) retention times, were determined. To study the permeability of the peptides, the Parallel Artificial Membrane Permeability Assay (PAMPA) was used as an in vitro model of the blood-brain barrier (BBB). Contrary to the parent peptide, the 15 analogs crossed the artificial membrane, thereby showing that N-methylation improved permeability. We also found that N-methylation enhanced lipophilicity but decreased the water solubility of peptides. Our results showed that both the number and position of N-methylated residues are important factors governing the physicochemical properties of peptides. There was no correlation between the number of N-methylated amide bonds and any of the properties measured. However, for the peptides consecutively N-methylated from the N-terminus to the C-terminus (p1, p5, p11, p12 and p16), lipophilicity correlated well with the number of N-methylated amide bonds and the permeability of the peptides. Moreover, the peptides were non-toxic to HEK293T cells, as determined by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Plasma sprayed thermal barrier coatings for industrial gas turbines: morphology, processing and properties

    International Nuclear Information System (INIS)

    Gruenling, H.W.; Mannsmann, W.

    1993-01-01

    Thermal barrier coatings out of fully or partially stabilized zirconia offer a unique chance in gas turbines to increase the gas inlet temperature significantly while keeping the temperature of the structural material of the component within conventional limits. The protection of combustor parts and transition pieces as well as of some stationary gas turbine parts however is state of the art. As a consequence of still insufficient reliability, the application for hot rotating parts is very limited. The introduction as a design element requires safe life within defined time intervals. These depend on the overhaul and repair intervals of the engines. For large land based industrial or utility gas turbines, for example, coating life between 25.000 and 30.000 hrs. is a minimum requirement. Premature failure of a coating by e.g. local spalling causes local overheating of the component with the consequence of its total destruction or even more expensive secondary damages. Life limiting is the corrosion rate at the ceramic-metal interface and the behavior of the coated system under transient operating conditions, where multiaxial strain and stress distributions are generated. Sufficient strain tolerance of the coating both under tensile as well as compressive conditions is required. The properties of thermal barrier coating systems depend strongly on the structure and phase composition of the coating layers and the morphology of and the adhesion at the ceramic-metal interface. They have to be controlled by the process itself, the process parameters and the characteristics of the applied materials (e.g. chemical composition, processing, morphology, particle size and size distribution). It will be reviewed, how properties and structures of coating systems correlate and how structures can be modified by careful control of the process parameters. (orig.)

  3. Reduction of microbial contamination and improvement of germination of sweet basil (Ocimum basilicum L.) seeds via surface dielectric barrier discharge

    Czech Academy of Sciences Publication Activity Database

    Ambrico, P. F.; Šimek, Milan; Morano, M.; De Miccolis Angelini, R.M.; Minafra, A.; Trotti, P.; Ambrico, M.; Prukner, Václav; Faretra, F.

    2017-01-01

    Roč. 50, č. 30 (2017), č. článku 305401. ISSN 0022-3727 R&D Projects: GA ČR(CZ) GA15-04023S Institutional support: RVO:61389021 Keywords : dielectric barrier discharges (DBD) * bio-decontamination * etching * polymers * biomolecules * spores * surface treatment Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.588, year: 2016 https://doi.org/10.1088/1361-6463/aa77c8

  4. Microbial community, and biochemical and physiological properties of Korean traditional black raspberry (Robus coreanus Miquel) vinegar.

    Science.gov (United States)

    Song, Nho-Eul; Cho, Sung-Ho; Baik, Sang-Ho

    2016-08-01

    The aim of this study was to elucidate the changes in microbial community and biochemical and physiological properties of traditional Muju black raspberry (Robus coreanus Miquel) vinegar (TMBV) during fermentation by culture-independent methods. During vinegar fermentation, ethanol produced up to 120 g L(-1) until day 35, with continuously increasing yeast concentration to a total of log 7.6 CFU mL(-1) . After day 35, acetic acid bacteria (AAB) concentrations rose to log 5.8 CFU mL(-1) until day 144. Denaturing gradient gel electrophoresis analysis showed that Saccharomyces cerevisiae was detected until day 87 of the fermentation, at which point Acetobacter pasteurianus gradually took over as the dominant species. Total sugar was reduced to 6.6 °Brix and total acidity produced up to 44 g L(-1) . In this study, we established the physicochemical analysis and growth dynamics of yeast and AAB during alcoholic and acetic acid fermentation of black raspberry by a traditional method. Overall, S. cerevisiae and A. pasteurianus species appeared to dominate the TMBV fermentation. In conclusion, this study demonstrated a suitable fermentation system for TMBV by the static surface method. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

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

    Science.gov (United States)

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

    2015-01-01

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

  6. Effects of Calcium Source on Biochemical Properties of Microbial CaCO3 Precipitation.

    Science.gov (United States)

    Xu, Jing; Du, Yali; Jiang, Zhengwu; She, Anming

    2015-01-01

    The biochemical properties of CaCO3 precipitation induced by Sporosarcina pasteurii, an ureolytic type microorganism, were investigated. Effects of calcium source on the precipitation process were examined, since calcium source plays a key role in microbiologically induced mineralization. Regardless of the calcium source type, three distinct stages in the precipitation process were identified by Ca(2+), NH4 (+), pH and cell density monitoring. Compared with stage 1 and 3, stage 2 was considered as the most critical part since biotic CaCO3 precipitation occurs during this stage. Kinetics studies showed that the microbial CaCO3 precipitation rate for calcium lactate was over twice of that for calcium nitrate, indicating that calcium lactate is more beneficial for the cell activity, which in turn determines urease production and CaCO3 precipitation. X-ray diffraction analysis confirmed the CaCO3 crystal as calcite, although scanning electron microscopy revealed a difference in crystal size and morphology if calcium source was different. The findings of this paper further suggest a promising application of microbiologically induced CaCO3 precipitation in remediation of surface and cracks of porous media, e.g., cement-based composites, particularly by using organic source of calcium lactate.

  7. The chemical properties and microbial community characterization of the thermophilic microaerobic pretreatment process.

    Science.gov (United States)

    Fu, Shan-Fei; He, Shuai; Shi, Xiao-Shuang; Katukuri, Naveen Reddy; Dai, Meng; Guo, Rong-Bo

    2015-12-01

    Thermophilic microaerobic pretreatment (TMP) was recently reported as an efficient pretreatment method of anaerobic digestion (AD). In this study, the chemical properties and microbial community were characterized to reveal how TMP working. Compared with thermophilic treatment under anaerobic condition (TMP0), cellulase activity obviously improved under microaerobic condition (TMP1), which was 10.9-49.0% higher than that of TMP0. Reducing sugar, SCOD and VFAs concentrations of TMP1 were 2.6-8.9%, 1.8-4.8% and 13.8-24% higher than those of TMP0, respectively. TMP gave obvious rise to phylum Firmicutes, which associated with extracellular enzymes production. The proportion of class Bacilli (belongs to phylum Firmicutes and mainly acts during hydrolysis) in TMP1 was 124.89% higher than that of TMP0, which reflected the greater hydrolytic ability under microaerobic condition. The improved abundance of phylum Firmicutes (especially class Bacilli, order Bacillales) under microaerobic condition could be the fundamental reason for the improved AD performance of thermophilic microaerobic pretreated corn straw. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Effect of gamma irradiation on the microbial load, chemical and sensory properties of the goat meat

    International Nuclear Information System (INIS)

    Al-Bachir, M.; Zeinou, R.

    2010-07-01

    The present study was undertaken to assess the quality characteristics and to evaluate the effects of gamma irradiation (0, 2, 4, and 6 kGy) of Jabaly Syrian goat meat on microbiological, chemical, and sensory characteristics during storage at 4 degree centigrade (1, 3, 4, and 5 weeks). Irradiation was effective in reducing the microbial load and increasing the shelf-life of goat meat. The radiation doses required to reduce the microorganisms by 90 percent (D10) in goat meat were 294 and 400 Gy for the Salmonella and E. coli, respectively. The main fatty acids identified from the goat meat were oleic, stearic, and palmitic acids. No significant differences were observed in moisture, crud protein, crud fat, ash, pH value, fatty acids, total acidity, volatile basic nitrogen, and sensory properties (texture, flavor, color, and taste) of the radiation processing and non-irradiated goat meat. Lipid peroxidation measured in term of thiobarbituric acid-reactive substances (TBARS) on irradiation and chilled storage increased. (Author)

  9. Microbial-Induced Heterogeneity in the Acoustic Properties of Porous Media

    Science.gov (United States)

    Acoustic wave data were acquired over a two-dimensional region of a microbial-stimulated sand column and an unstimulated sand column to assess the spatiotemporal changes in a porous medium caused by microbial growth and biofilm formation. The acoustic signals from the unstimulate...

  10. Physical, mechanical and barrier properties of corn starch films incorporated with plant essential oils.

    Science.gov (United States)

    Ghasemlou, Mehran; Aliheidari, Nahal; Fahmi, Ronak; Shojaee-Aliabadi, Saeedeh; Keshavarz, Behnam; Cran, Marlene J; Khaksar, Ramin

    2013-10-15

    Corn starch-based films are inherently brittle and lack the necessary mechanical integrity for conventional packaging. However, the incorporation of additives can potentially improve the mechanical properties and processability of starch films. In this work two essential oils, Zataria multiflora Boiss (ZEO) or Mentha pulegium (MEO) at three levels (1%, 2% and 3% (v/v)), were incorporated into starch films using a solution casting method to improve the mechanical and water vapor permeability (WVP) properties and to impart antimicrobial activity. Increasing the content of ZEO or MEO from 2% to 3% (v/v) increased values for elongation at break from 94.38% to 162.45% and from 53.34% to 107.71% respectively, but did not significantly change tensile strength values of the films. The WVP properties of the films decreased from 7.79 to 3.37 or 3.19 g mm m(-2) d(-1) kPa(-1) after 3% (v/v) ZEO or MEO incorporation respectively. The oxygen barrier properties were unaffected at the 1% and 2% (v/v) oil concentration used but oxygen transmission increased with 3% (v/v) for both formulations. The films' color became slightly yellow as the levels of ZEO or MEO were increased although transparency was maintained. Both films demonstrated antimicrobial activity with films containing ZEO more effective against Escherichia coli and Staphylococcus aureus than those containing MEO. These results suggest that ZEO and MEO have the potential to be directly incorporated into corn starch to prepare antimicrobial biodegradable films for various food packaging applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Preparation and Characterization of Composites Based on Polylactic Acid and Beeswax with Improved Water Vapor Barrier Properties.

    Science.gov (United States)

    Lim, Jung Hoon; Kim, Jeong Ae; Ko, Jung A; Park, Hyun Jin

    2015-11-01

    Beeswax and a plasticizer (ATBC) were added to polylactic acid (PLA) films in order to enhance the water vapor barrier properties of the films. Beeswax improved the barrier properties; the water vapor permeability in the composite containing 1% beeswax was 58% lower than that of the neat PLA. Fourier transform infrared spectroscopy and X-ray diffraction analysis revealed that the incorporation of beeswax and ATBC had so little effect on the PLA structure. In addition, the structure of PLA did not vary substantially with the additions. The surfaces of the composites were examined by using field emission scanning electron microscopy. Differential scanning calorimetry results showed that the degree of crystallinity of the PLA films increased with the addition of beeswax and ATBC. However, the tensile strength and elongation at break of the composites containing beeswax were up to approximately 50% lower than those of the neat PLA. Although further study is needed to improve the mechanical properties, the aforementioned results showed that the PLA barrier properties can be improved by the incorporation of a small amount of beeswax and ATBC. The results of this study can be applied for the preparation of PLA composite films with improved barrier properties. Such biodegradable films are extremely useful for applications in the food packaging industry. © 2015 Institute of Food Technologists®

  12. Long-term reactive nitrogen loading alters soil carbon and microbial community properties in a subalpine forest ecosystem

    Science.gov (United States)

    Boot, Claudia M.; Hall, Ed K.; Denef, Karolien; Baron, Jill S.

    2016-01-01

    Elevated nitrogen (N) deposition due to increased fossil fuel combustion and agricultural practices has altered global carbon (C) cycling. Additions of reactive N to N-limited environments are typically accompanied by increases in plant biomass. Soil C dynamics, however, have shown a range of different responses to the addition of reactive N that seem to be ecosystem dependent. We evaluated the effect of N amendments on biogeochemical characteristics and microbial responses of subalpine forest organic soils in order to develop a mechanistic understanding of how soils are affected by N amendments in subalpine ecosystems. We measured a suite of responses across three years (2011–2013) during two seasons (spring and fall). Following 17 years of N amendments, fertilized soils were more acidic (control mean 5.09, fertilized mean 4.68), and had lower %C (control mean 33.7% C, fertilized mean 29.8% C) and microbial biomass C by 22% relative to control plots. Shifts in biogeochemical properties in fertilized plots were associated with an altered microbial community driven by reduced arbuscular mycorrhizal (control mean 3.2 mol%, fertilized mean 2.5 mol%) and saprotrophic fungal groups (control mean 17.0 mol%, fertilized mean 15.2 mol%), as well as a decrease in N degrading microbial enzyme activity. Our results suggest that decreases in soil C in subalpine forests were in part driven by increased microbial degradation of soil organic matter and reduced inputs to soil organic matter in the form of microbial biomass.

  13. Microbial status, aerobic stability and fermentation of maize silage sealed with an oxygen barrier film or standard polyethylene film

    Directory of Open Access Journals (Sweden)

    Szilvia Orosz

    2013-03-01

    Full Text Available An experiment was conducted to compare a bunker silo sealing system comprising an oxygen barrier film (OB: 45μm thickness with protective woven polypropylene with one comprising standard black polyethylene film (S; 125μm thickness with protective tyres. Analysis of samples taken to 30 cm depth after 365 days of storage showed no differences in pH or lactic acid between the two sealing systems. There were no differences in aerobic bacterial count between silages. Whilst 2.56 log10 CFU moulds g-1 fresh weight were found in samples of silage sealed with S, no moulds were found in samples of silage sealed with OB. Aerobic stability, averaged 249 hours and 184 hours for OB and S, respectively. The OB system probably inhibited the development of the micro-organisms responsible for the initiation of aerobic deterioration to a greater extent than the standard silo sealing system.  

  14. Influence of graphene oxide on mechanical, morphological, barrier, and electrical properties of polymer membranes

    Directory of Open Access Journals (Sweden)

    Ali Ammar

    2016-03-01

    Full Text Available This paper expresses a short review of research on the effects of graphene oxide (GO as a nanocomposite element on polymer morphology and resulting property modifications including mechanical, barrier, and electrical conductivity. The effects on mechanical enhancement related to stress measurements in particular are a focus of this review. To first order, varying levels of aggregation of GO in different polymer matrices as a result of their weak inter-particle attractive interactions mainly affect the nanocomposite mechanical properties. The near surface dispersion of GO in polymer/GO nanocomposites can be investigated by studying the surface morphology of these nanocomposites using scanning probe microscopy such as atomic force microscope (AFM and scanning electron microscope (SEM. In the bulk, GO dispersion can be studied by wide-angle X-ray scattering (WAXD by analyzing the diffraction peaks corresponding to the undispersed GO fraction in the polymer matrix. In terms of an application, we review how the hydrophilicity of graphene oxide and its hydrogen bonding potential can enhance water flux of these nanocomposite materials in membrane applications. Likewise, the electrical conductivity of polymer films and bulk polymers can be advantageously enhanced via the percolative dispersion of GO nanoparticles, but this typically requires some additional chemical treatment of the GO nanoparticles to transform it to reduced GO.

  15. Load rate dependence of the mechanical properties of thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Zotov, Nikolay; Eggeler, Gunther [Institut fuer Werkstoffe, Ruhr Universitaet Bochum, 44780 Bochum (Germany); Bartsch, Marion [Institut fuer Werkstoff-Forschung, DLR Koeln, 51147 Koeln (Germany)

    2009-07-01

    Thermal barrier coatings (TBC), composed of yttrium-stabilized zirconia (YSZ) ceramic top coat (TC) and intermetallic NiCoCrAlY bond coat (BC) are commonly used as protective coatings of Ni-based high temperature gas engine components. Nanoindentation techniques are increasingly applied for determining the TBC mechanical properties on a nanometre scale. However, little is known about the load-rate dependence of the mechanical properties, which is important for better understanding of cyclic thermal fatigue experiments. Nanoindentations with different load rates omega were performed on polished cross-sections of TBC, deposited by EB-PVD on IN625 substrates (S), using a XP Nanoindenter (MTS) equipped with Berkovich diamond tip. The Young's modulus (E) of the TC is independent of omega, while E for the BC and the S decreases with omega. The hardness (H) of the TC and the BC increases, while H for the S decreases with omega. From the dependence of H on omega, creep power-law exponents c = 0.24(11) and c = 0.023(6) for the TC and the BC were determined. For all TBC components, a decrease with omega of the power-law exponents n and m, describing the loading and unloading nanoindentation curves, is observed.

  16. Barrier Properties of Polylactic Acid in Cellulose Based Packages Using Montmorillonite as Filler

    Directory of Open Access Journals (Sweden)

    Daniela Sánchez Aldana

    2014-09-01

    Full Text Available Polylactic acid (PLA and montmorillonite (CB as filler were studied as coatings for cellulose based packages. Amorphous (AM and semi crystalline (SC PLA were used at different concentrations according to a 2 × 6 × 3 full factorial experimental design. CB loading was three concentrations and coating was performed by casting. Contact angle (CA, water vapor (WVP and grease permeabilities were measured for each resultant package and were compared to commercial materials (Glassine Paper, Grease Proof Papers 1 and 2 produced commercially. Significant differences were found and the main factors were the type and concentration of PLA. The best values were: for grease penetration, +1800 s; WVP from 161.36 to 237.8 g·µm·kPa−1·m−2·d−1 and CA from 69° to 73° for PLA–AM 0.5% and CB variable. These parameters are comparable to commercial packages used in the food industry. DSC revealed three different thermal events for PLA–SC and just Tg for PLA–AM. Crystallinity was also verified, obtaining a ΔHcrys of 3.7 J·g−1 for PLA–SC and 14 J·g−1 for PLA–SC–BC, evidencing clay interaction as a crystal nucleating agent. Differences found were explained on terms of the properties measured, where structural and chemical arrays of the coatings play a fundamental role for the barrier properties.

  17. Mechanical properties of EB-PVD ZrO2 thermal barrier coatings

    International Nuclear Information System (INIS)

    Held, Carolin

    2014-01-01

    In this work, the elastic properties of thermal barrier coatings which were produced by electron-beam enhanced physical vapour deposition were investigated, as well as the dependency of the properties on the sample microstructure, the thermal treatment and the test method. For this purpose, not only commercial coatings were characterized, but also special sample material was used which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 C, 1100 C and 1200 C and then tested in a specially developed miniaturized bend test and by dynamic mechanical analysis. The sample material was tested by nanoindentation in order to measure the Young's modulus on a local scale, and the porosity of the samples was determined by microstructure analysis and porosimetry. The decrease of porosity could be connected with sintering and subsequent stiffening of the material. The test results are dependent on the tested volume. A small test volume leads to larger measured Young's moduli, while a large test volume yields lower values. The test volume also has an influence on the increase of stiffness during thermal exposure. With a small tested volume, a quicker increase of the Young's modulus was registered, which could be associated to the sintering of local structures.

  18. Effects of air dielectric barrier discharge plasma treatment time on surface properties of PBO fiber

    International Nuclear Information System (INIS)

    Wang Qian; Chen Ping; Jia Caixia; Chen, Mingxin; Li Bin

    2011-01-01

    In this paper, the effects of air dielectric barrier discharge (DBD) plasma treatment time on surface properties of poly(p-phenylene benzobisoxazole) (PBO) fiber were investigated. The surface characteristics of PBO fiber before and after the plasma treatments were analyzed by dynamic contact angle (DCA) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). DCA measurements indicated that the surface wettability of PBO fiber was improved significantly by increasing the fiber surface free energy via air DBD plasma treatments. The results were confirmed by the improvement of adhesion of a kind of thermoplastic resin to PBO fiber which was observed by SEM, showing that more resin was adhering evenly to the fiber surface. AFM measurement revealed that the surface topography of PBO fiber became more complicated and the surface roughness was greatly enhanced after the plasma treatments, and XPS analysis showed that some new polar groups (e.g. -O-C=O) were introduced on plasma treated PBO fiber surface. The results of this study also showed that the surface properties of PBO fiber changed with the elongation of plasma treatment time.

  19. Effects of Microbial Transglutaminase on Physicochemical, Microbial and Sensorial Properties of Kefir Produced by Using Mixture Cow’s and Soymilk

    Science.gov (United States)

    2017-01-01

    The objective of this research was to investigate the effects microbial transglutaminase (m-TGs) on the physicochemical, microbial and sensory properties of kefir produced by using mix cow and soymilk. Kefir batches were prepared using 0, 0.5, 1 and 1.5 Units m-TGs for per g of milk protein. Adding m-TGs to milk caused an increase in the pH and viscosity and caused a decrease in titratable acidity and syneresis in the kefir samples. Total bacteria, lactobacilli and streptococci counts decreased, while yeast counts increased in all the samples during storage. Alcohols and acids compounds have increased in all the samples except in the control samples, while carbonyl compounds have decreased in all the samples during storage (1-30 d). The differences in the percentage of alcohols, carbonyl compounds and acids in total volatiles on the 1st and the 30th d of storage were observed at 8.47-23.52%, 6.94-25.46% and 59.64-63.69%, respectively. The consumer evaluation of the kefir samples showed that greater levels of acceptability were found for samples which had been added 1.5 U m-TGs for per g of milk protein. PMID:28943774

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

    Science.gov (United States)

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

    2013-10-01

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

  1. Barrier and adhesion properties of anti-corrosion coatings based on surfactant-free latexes from anhydride-containing polymers

    NARCIS (Netherlands)

    Soer, W.J.; Ming, W.; Koning, C.E.; Benthem, van R.A.T.M.; Mol, J.M.C.; Terryn, H.

    2009-01-01

    We have successfully obtained surfactant-free latexes from anhydride-containing polymers, including poly(styrene-alt-maleic anhydride) (PSMA), maleinized polybutadiene (PBDMA), and poly(octadecene-alt-maleic anhydride) (POMA). Here we report barrier and adhesion properties of the coatings made from

  2. Soil microbial properties after long-term swine slurry application to conventional and no-tillage systems in Brazil.

    Science.gov (United States)

    Balota, Elcio L; Machineski, Oswaldo; Hamid, Karima I A; Yada, Ines F U; Barbosa, Graziela M C; Nakatani, Andre S; Coyne, Mark S

    2014-08-15

    Swine waste can be used as an agricultural fertilizer, but large amounts may accumulate excess nutrients in soil or contaminate the surrounding environment. This study evaluated long-term soil amendment (15 years) with different levels of swine slurry to conventional (plow) tillage (CT) and no tillage (NT) soils. Long-term swine slurry application did not affect soil organic carbon. Some chemical properties, such as calcium, base saturation, and aluminum saturation were significantly different within and between tillages for various application rates. Available P and microbial parameters were significantly affected by slurry addition. Depending on tillage, soil microbial biomass and enzyme activity increased up to 120 m(3) ha(-1) year(-1) in all application rates. The NT system had higher microbial biomass and activity than CT at all application levels. There was an inverse relationship between the metabolic quotient (qCO2) and MBC, and the qCO2 was 53% lower in NT than CT. Swine slurry increased overall acid phosphatase activity, but the phosphatase produced per unit of microbial biomass decreased. A comparison of data obtained in the 3rd and 15th years of swine slurry application indicated that despite slurry application the CT system degraded with time while the NT system had improved values of soil quality indicators. For these Brazilian oxisols, swine slurry amendment was insufficient to maintain soil quality parameters in annual crop production without additional changes in tillage management. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Impact of nano/micron vegetable carbon black on mechanical, barrier and anti-photooxidation properties of fish gelatin film.

    Science.gov (United States)

    Ding, Junsheng; Wu, Xiaomeng; Qi, Xiaona; Guo, Heng; Liu, Anjun; Wang, Wenhang

    2018-05-01

    In this paper, two kinds of commonly used vegetable carbon black (VCB, 3000 mesh; nano) at 50 g kg -1 concentration (based on dried gelatin) were added to 48 g kg -1 of fish gelatin (GEL) solutions and their effects on mechanical, barrier and anti-photooxidation properties of GEL films were investigated. From the SEM images, it was shown that compared with 3000 mesh VCB (1-2 μm), nano VCB (100-200 nm) made the microstructure of GEL film more compact and more gelatin chains were cross-linked by nano VCB. The addition of nano VCB significantly increased gelatin film strength with the greatest tensile strength of 52.589 MPa and stiffness with the highest Young's modulus of 968.874 MPa, but led to the reduction of film elongation. Also, the VCB presence significantly improved water vapour and oxygen barrier properties of GEL film. Importantly, nano VCB increased GEL film with better UV barrier property due to its stronger UV absorption nature when compared with micron VCB. This property could help in the preservation of oil samples in the photooxidation accelerated test. With improved properties, the nano VCB-reinforced GEL film may have great potential for application in the edible packaging field, especially for the anti-photooxidation property. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  4. Structural properties of ultraviolet cured polysilazane gas barrier layers on polymer substrates

    International Nuclear Information System (INIS)

    Morlier, Arnaud; Cros, Stéphane; Garandet, Jean-Paul; Alberola, Nicole

    2014-01-01

    Perhydropolysilazane (PHPS) conversion to silica through high energy ultraviolet irradiation has been studied. Precursor conversion speed and structural properties of the UV cured PHPS have been investigated and showed that this conversion method is fast but that complete conversion into silica is not achieved in an oxygen depleted atmosphere for layer thicknesses higher than 30 nm, resulting in a composite structure with concentration gradients. We further show that Fourier transform infrared spectroscopy data allow investigating the local structure and composition over the depth of the obtained layers. Gas permeability of the thin UV cured PHPS layers deposited on polymers has been studied. We used a high sensitivity permeation measurement technique to determine water vapor and oxygen permeabilities of the barrier layers and show the correlation between helium, oxygen and water permeability of these materials. Oxygen and water vapor transmission rates of respectively 0.06 cm 3 /m 2 /day/bar and 0.2 g/m 2 /day have been obtained with layers deposited on a polymer substrate. - Highlights: • Perhydropolysilazane has been converted into dense layers by vacuum UV irradiation. • Cured perhydropolysilazane layers have an inhomogeneous structure. • The cured material consists in 3 spontaneously formed layers. • Oxygen and water transmission rates of 0.06 cm 3 /m 2 /day/bar and 0.02 g/m 2 /day are reached

  5. Barrier Properties of Polymeric Packaging Materials to Major Aroma Volatiles in Herbs

    Directory of Open Access Journals (Sweden)

    Leelaphiwat Pattarin

    2016-01-01

    Full Text Available This study determined the main transport coefficients (diffusion, solubility and permeability of key aroma compounds present in tropical herbs (eucalyptol and estragol through low‒density polyethylene (LDPE, polypropylene (PP, nylon (Nylon, polyethylene terephthalate (PET, metalized‒polyethylene terephthalate (MPET and poly(lactic acid (PLA films at 15 and 25 °C. The concentration of aroma compounds permeating through the films were evaluated at various time intervals using a gas chromatograph flame ionization detector (GC–FID. Results showed that the diffusion coefficients of aroma compounds were highest in LDPE whereas the solubility coefficients were highest in PLA at both temperatures. PLA had the highest permeability coefficients for estragol at both temperatures. PP and LDPE had the highest permeability coefficients for eucalyptol at 15 and 25 °C, respectively. MPET had the lowest permeability for both aroma compounds studied. Aroma barrier properties can be used when selecting polymeric packaging materials to prevent aroma loss in various food and consumer products.

  6. Gas barrier properties of diamond-like carbon films coated on PTFE

    International Nuclear Information System (INIS)

    Ozeki, K.; Nagashima, I.; Ohgoe, Y.; Hirakuri, K.K.; Mukaibayashi, H.; Masuzawa, T.

    2009-01-01

    Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapour deposition (PE-CVD). Before the DLC coating, the PTFE substrate was modified with a N 2 plasma pre-treatment to enhance the adhesive strength of the DLC to the substrate. The influences of the N 2 plasma pre-treatment and process pressure on the gas permeation properties of these DLC-coated PTFE samples were investigated. In the Raman spectra, the G peak position shifted to a lower wave number with increasing process pressure. With scanning electron microscopy (SEM), a network of microcracks was observed on the surface of the DLC film without N 2 plasma pre-treatment. The density of these cracks decreased with increasing process pressure. In the film subjected to a N 2 plasma pre-treatment, no cracks were observed at any process pressure. In the gas barrier test, the gas permeation decreased drastically with increasing film thickness and saturated at a thickness of 0.2 μm. The DLC-coated PTFE with the N 2 plasma pre-treatment exhibited a greater reduction in gas permeation than did the samples without pre-treatment. For both sample types, gas permeation decreased with increasing process pressure.

  7. Mechanical Properties of Layered La2Zr2O7 Thermal Barrier Coatings

    Science.gov (United States)

    Guo, Xingye; Li, Li; Park, Hyeon-Myeong; Knapp, James; Jung, Yeon-Gil; Zhang, Jing

    2018-04-01

    Lanthanum zirconate (La2Zr2O7) has been proposed as a promising thermal barrier coating (TBC) material due to its low thermal conductivity and high stability at high temperatures. In this work, both single and double-ceramic-layer (DCL) TBC systems of La2Zr2O7 and 8 wt.% yttria-stabilized zirconia (8YSZ) were prepared using air plasma spray (APS) technique. The thermomechanical properties and microstructure were investigated. Thermal gradient mechanical fatigue (TGMF) tests were applied to investigate the thermal cycling performance. The results showed that DCL La2Zr2O7 + 8YSZ TBC samples lasted fewer cycles compared with single-layered 8YSZ TBC samples in TGMF tests. This is because DCL La2Zr2O7 TBC samples had higher residual stress during the thermal cycling process, and their fracture toughness was lower than that of 8YSZ. Bond strength test results showed that 8YSZ TBC samples had higher bond strength compared with La2Zr2O7. The erosion rate of La2Zr2O7 TBC samples was higher than that of 8YSZ samples, due to the lower critical erodent velocity and fracture toughness of La2Zr2O7. DCL porous 8YSZ + La2Zr2O7 had a lower erosion rate than other SCL and DCL La2Zr2O7 coatings, suggesting that porous 8YSZ serves as a stress-relief buffer layer.

  8. Influence of chitosan concentration on mechanical and barrier properties of corn starch/chitosan films.

    Science.gov (United States)

    Ren, Lili; Yan, Xiaoxia; Zhou, Jiang; Tong, Jin; Su, Xingguang

    2017-12-01

    The active packaging films based on corn starch and chitosan were prepared through mixing the starch solution and the chitosan solution (1:1) by casting. The aim of this work was to characterize and analyze the effects of the chitosan concentrations (0, 21, 41, 61 and 81wt% of starch) on physicochemical, mechanical and water vapor barrier properties as well as morphological characteristics of the corn starch/chitosan (CS/CH) films. Starch molecules and chitosan could interact through hydrogen bonding as confirmed from the shift of the main peaks to higher wavenumbers in FTIR and the reduction of crystallinity in XRD. Results showed that the incorporation of chitosan resulted in an increase in film solubility, total color differences, tensile strength and elongation at break and a decrease in Young's modulus and water vapor permeability (WVP). Elongation at break of the CS/CH films increased with increasing of chitosan concentration, and reached a maximum at 41 wt%, then declined at higher chitosan concentration. The WVP of CS/CH films increased with an increase of chitosan concentration and the same tendency observed for the moisture content. The results suggest that this biodegradable CS/CH films could potentially be used as active packaging films for food and pharmaceutical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The influence of creep properties on crack propagation in thermal barrier coatings

    International Nuclear Information System (INIS)

    Baeker, Martin

    2010-01-01

    Thermal barrier coatings are used to protect turbine blades from the high temperature of the process gas inside a turbine. They consist of a metallic bond coat and of a ceramic top coat with low thermal conductivity. During service, an additional oxide layer forms between bond coat and top coat that eventually causes failure. Finite element simulations show that the roughness of the interface between top and bond coat is crucial for determining the stress state. Lifetime models have been inferred that assume that cracks form in the peak positions at small oxide thickness and propagate when the oxide layer grows and the stress field shifts. A two-dimensional finite element model of crack propagation in the TBC layer is presented. Since the cracks propagate near a material interface and since plasticity may occur in the bond coat, standard tools of fracture mechanics for predicting the crack propagation direction are difficult to apply. This problem is circumvented in a very simple way by propagating short 'test cracks' in different directions and optimising to find the crack direction with the maximum energy release rate. It is shown that the energy release rate and the crack propagation direction are sensitive to the details of the stress state and especially to the creep properties of the materials. Implications for failure models are discussed.

  10. Oxygen Barrier Properties and Melt Crystallization Behavior of Poly(ethylene terephthalate/Graphene Oxide Nanocomposites

    Directory of Open Access Journals (Sweden)

    Anna Szymczyk

    2015-01-01

    Full Text Available Poly(ethylene terephthalate nanocomposites with low loading (0.1–0.5 wt% of graphene oxide (GO have been prepared by using in situ polymerization method. TEM study of nanocomposites morphology has shown uniform distribution of highly exfoliated graphene oxide nanoplatelets in PET matrix. Investigations of oxygen permeability of amorphous films of nanocomposites showed that the nanocomposites had better oxygen barrier properties than the neat PET. The improvement of oxygen permeability for PET nanocomposite films over the neat PET is approximately factors of 2–3.3. DSC study on the nonisothermal crystallization behaviors proves that GO acts as a nucleating agent to accelerate the crystallization of PET matrix. The evolution of the lamellar nanostructure of nanocomposite and neat PET was monitored by SAXS during nonisothermal crystallization from the melt. It was found that unfilled PET and nanocomposite with the highest concentration of GO (0.5 wt% showed almost similar values of the long period (L=11.4 nm for neat PET and L=11.5 nm for PET/0.5GO.

  11. The influence of the structures and compounds of DLC coatings on the barrier properties of PET bottles

    International Nuclear Information System (INIS)

    Li, Yang; Zhen-Duo, Wang; Shou-Ye, Zhang; Li-Zhen, Yang; Qiang, Chen

    2009-01-01

    To reduce the oxygen transmission rate through a polyethylene terephthalate (PET) bottle (an organic plastic) diamond-like carbon (DLC) coatings on the inner surface of the PET bottle were deposited by radio frequency plasma-enhanced chemical vapour deposition (RF-PECVD) technology with C 2 H 2 as the source of carbon and Ar as the diluted gas. As the barrier layer to humidity and gas permeation, this paper analyses the DLC film structure, composition, morphology and barrier properties by Fourier transform infrared, atomic force microscopy, scanning electron microscopy and oxygen transmission rate in detail. From the spectrum, it is found that the DLC film mainly consists of sp 3 bonds. The barrier property of the films is significantly relevant to the sp 3 bond concentration in the coating, the film thickness and morphology. Additionally, it is found that DLC film deposited in an inductively coupled plasma enhanced capacitively coupled plasma source shows a compact, homogeneous and crack-free surface, which is beneficial for a good gas barrier property in PET bottles. (fluids, plasmas and electric discharges)

  12. Mechanical and barrier properties of starch-based films plasticized with two- or three component deep eutectic solvents.

    Science.gov (United States)

    Zdanowicz, Magdalena; Johansson, Caisa

    2016-10-20

    The aim of this work was to prepare two- and three-components deep eutectic solvents (DES) and investigate their potential as starch plasticizers. Starch/DES films were prepared via casting method. Mechanical properties, water vapor- and oxygen transmission rates were measured; additionally contact angle and moisture sorption were determined and FTIR analysis was applied on the films. Native potato starch and hydroxypropylated and oxidized starch (HOPS) with common plasticizers (e.g. polyols, urea) and DES were studied. Moreover, influence of three methods of DES introduction and concentration of plasticizer on the films properties were compared. HOPS films were prepared by two methods: as non-cured and cured samples. Some of DESs containing citrate anion exhibited crosslinking ability of polysaccharide matrix. Non-cured HOPS/DES films exhibited more favourable mechanical and barrier properties than cured analogue films. Samples prepared with unmodified potato starch had higher mechanical and barrier properties than films made with HOPS. Starch-based films plasticized with novel DESs with parallel crosslinking activity exhibited satisfactory mechanical and barrier properties. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Dispersion of SiC nanoparticles in cellulose for study of tensile, thermal and oxygen barrier properties.

    Science.gov (United States)

    Kisku, Sudhir K; Dash, Satyabrata; Swain, Sarat K

    2014-01-01

    Cellulose/silicon carbide (cellulose/SiC) nanobiocomposites were prepared by solution technique. The interaction of SiC nanoparticles with cellulose were confirmed by Fourier transformed infrared (FTIR) spectroscopy. The structure of cellulose/SiC nanobiocomposites was investigated by X-ray diffraction (XRD), and transmission electron microscopy (TEM). The tensile properties of the nanobiocomposites were improved as compared with virgin cellulose. Thermal stabilities of cellulose/SiC nanobiocomposites were studied by thermogravimetric analysis (TGA). The cellulose/SiC nanobiocomposites were thermally more stable than the raw cellulose. It may be due to the delamination of SiC with cellulose matrix. The oxygen barrier properties of cellulose composites were measured using gas permeameter. A substantial reduction in oxygen permeability was obtained with increase in silicon carbide concentrations. The thermally resistant and oxygen barrier properties of the prepared nanobiocomposites may enable the materials for the packaging applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Reinforcement of the Gas Barrier Properties of Polyethylene and Polyamide Through the Nanocomposite Approach: Key Factors and Limitations

    Directory of Open Access Journals (Sweden)

    Picard E.

    2015-02-01

    Full Text Available In this study, polyamide 6 (PA6 and polyethylene (PE nanocomposites were prepared from melt blending and a detailed characterization of the nanocomposite morphology and gas barrier properties was performed. The choice of the organoclay was adapted to each polymer matrix. Exfoliated morphology and improved gas transport properties were obtained by melt mixing the polar PA6 matrix and the organoclay, whereas a microcomposite with poor barrier properties was formed from the binary PE/organomodified clay mixture. Different modified polyethylenes were examined as compatibilizers for the polyethylene/organoclay system. The effect of compatibilizer molar mass, polarity and content was investigated on the clay dispersion and on the gas barrier properties. The optimal compatibilizer to clay weight ratio was found to be equal to 4 whatever the compatibilizer. However, a high degree of clay delamination was obtained with the high molar mass compatibilizer whereas highly swollen clay aggregates resulted from the incorporation of the low molar mass interfacial agents. Contrary to the PA based system, the barrier properties of PE nanocomposites were not directly related to the clay dispersion state but resulted also from the matrix/clay interfacial interactions. Oxidized wax was identified as a very promising interfacial agent and a step by step study was performed to optimize the gas transport properties of the systems based on PE, oxidized wax and organoclay. In particular, an interesting combination of oxidized wax and high molar mass maleic anhydride grafted polyethylene allowing dividing the gas permeability by a factor 2 in comparison with neat PE was proposed.

  15. Gas barrier properties of hydrogenated amorphous carbon films coated on polyethylene terephthalate by plasma polymerization in argon/n-hexane gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Polonskyi, Oleksandr; Kylián, Ondřej, E-mail: ondrej.kylian@gmail.com; Petr, Martin; Choukourov, Andrei; Hanuš, Jan; Biederman, Hynek

    2013-07-01

    Hydrogenated amorphous carbon thin films were deposited by RF plasma polymerization in argon/n-hexane gas mixture on polyethylene terephthalate (PET) foils. It was found that such deposited films may significantly improve the barrier properties of PET. It was demonstrated that the principal parameter that influences barrier properties of such deposited films towards oxygen and water vapor is the density of the coatings. Moreover, it was shown that for achieving good barrier properties it is advantageous to deposit coatings with very low thickness. According to the presented results, optimal thickness of the coating should not be higher than several tens of nm. - Highlights: • a-C:H films were prepared by plasma polymerization in Ar/n-hexane atmosphere. • Barrier properties of coatings are dependent on their density and thickness. • Highest barrier properties were observed for films with thickness 15 nm.

  16. Long-term application of bioorganic fertilizers improved soil biochemical properties and microbial communities of an apple orchard soil

    Directory of Open Access Journals (Sweden)

    Wang Lei

    2016-11-01

    Full Text Available Soil biochemical properties and microbial communities are usually considered as important indicators of soil health because of their association with plant nutrition. In this study, we investigated the impact of long-term application of bioorganic fertilizer (BOF on soil biochemical properties and microbial communities in the apple orchard soil of the Loess Plateau. The experiment included three treatments: (1 control without fertilization (CK; (2 chemical fertilizer application (CF; and (3 bioorganic fertilizer application (BOF. The high throughput sequencing was used to examine the bacterial and fungal communities in apple orchard soil. The results showed that the BOF treatment significantly increased the apple yield during the experimental time (2009-2015. The application of BOF significantly increased the activities of catalase and invertase compared to those in CK and CF treatments. The high throughput sequencing data showed that the application of BOF changed the microbial community composition of all soil depths considered (0-20cm, 20-40cm, and 40-60cm, e.g., the relative abundance of bio-control bacteria (Xanthomonadales, Lysobacter, Pseudomonas and Bacillus, Proteobacteria, Bacteroidetes, Ohtaekwangia, Ilyonectria and Lecanicillium was increased while that of Acidobacteria, Chloroflexi, Gp4, Gp6 and Sphaerobacter was decreased. The increase in apple yield after the application of BOF might be due to increase in organic matter, total nitrogen and catalase and invertase activities of soil and change in the bacterial community composition by enriching Bacillus, Pseudomonas, Lysobacter and Ohtaekwangia. These results further enhance the understanding on how BOFs alter soil microbial community composition to stimulate soil productivity.

  17. Correlation of morphology and barrier properties of thin microwave plasma polymer films on metal substrate

    International Nuclear Information System (INIS)

    Barranco, V.; Carpentier, J.; Grundmeier, G.

    2004-01-01

    The barrier properties of thin model organosilicon plasma polymers layers on iron are characterised by means of electrochemical impedance spectroscopy (EIS). Tailored thin plasma polymers of controlled morphology and chemical composition were deposited from a microwave discharge. By the analysis of the obtained impedance diagrams, the evolution of the water uptake φ, coating resistance and polymer capacitance with immersion time were monitored and the diffusion coefficients of the water through the films were calculated. The impedance data correlated well with the chemical structure and morphology of the plasma polymer films with a thickness of less than 100 nm. The composition of the films were determined by means of infrared reflection absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The morphology of the plasma polymer surface and the interface between the plasma polymer and the metal were characterised using atomic force microscopy (AFM). It could be shown that, at higher pressure, the film roughness increases which is probably due to the adsorption of plasma polymer nanoparticles formed in the plasma bulk and the faster film growth. This leads to voids with a size of a few tens of nanometers at the polymer/metal interface. The film roughness increases from the interface to the outer surface of the film. By lowering the pressure and thereby slowing the deposition rate, the plasma polymers perfectly imitate the substrate topography and lead to an excellent blocking of the metal surface. Moreover, the ratio of siloxane bonds to methyl-silyl groups increases which implies that the crosslink density is higher at lower deposition rate. The EIS data consistently showed higher coating resistance as well as lower interfacial capacitance values and a better stability over time for the film deposited at slower pressure. The diffusion coefficient of water in thin and ultra-thin plasma

  18. Enhancing Electrophoretic Display Lifetime: Thiol-Polybutadiene Evaporation Barrier Property Response to Network Microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Caitlyn Christian [California State Polytechnic State Univ., San Luis Obispo, CA (United States)

    2017-02-27

    An evaporation barrier is required to enhance the lifetime of electrophoretic deposition (EPD) displays. As EPD functions on the basis of reversible deposition and resuspension of colloids suspended in a solvent, evaporation of the solvent ultimately leads to device failure. Incorporation of a thiol-polybutadiene elastomer into EPD displays enabled display lifetime surpassing six months in counting and catalyzed rigid display transition into a flexible package. Final flexible display transition to mass production compels an electronic-ink approach to encapsulate display suspension within an elastomer shell. Final thiol-polybutadiene photosensitive resin network microstructure was idealized to be dense, homogeneous, and expose an elastic response to deformation. Research at hand details an approach to understanding microstructural change within display elastomers. Polybutadiene-based resin properties are modified via polymer chain structure, with and without added aromatic urethane methacrylate difunctionality, and in measuring network response to variation in thiol and initiator concentration. Dynamic mechanical analysis results signify that cross-linked segments within a difunctionalized polybutadiene network were on average eight times more elastically active than that of linked segments within a non-functionalized polybutadiene network. Difunctionalized polybutadiene samples also showed a 2.5 times greater maximum elastic modulus than non-functionalized samples. Hybrid polymer composed of both polybutadiene chains encompassed TE-2000 stiffness and B-1000 elasticity for use in encapsulating display suspension. Later experiments measured kinetic and rheological response due to alteration in dithiol cross-linker chain length via real time Fourier transform infrared spectroscopy and real-time dynamic rheology. Distinct differences were discovered between dithiol resin systems, as maximum thiol conversion achieved in short and long chain length dithiols was 86% and

  19. Composition, structure and electrical properties of alumina barrier layers grown in fluoride-containing oxalic acid solutions

    Energy Technology Data Exchange (ETDEWEB)

    Jagminas, A. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)], E-mail: jagmin@ktl.mii.lt; Vrublevsky, I. [Department of Microelectricals, Belarusian State University of Informatics and Radioelectricals, 6 Brovka Street, Minsk 220013 (Belarus); Kuzmarskyte, J.; Jasulaitiene, V. [Institute of Chemistry, A. Gostauto 9, LT-01108 Vilnius (Lithuania)

    2008-04-15

    The composition, structure and electrical properties of alumina barrier layers grown by anodic oxidation in F{sup -}-containing (FC) and F{sup -}-free (FF) oxalic acid solutions were studied using the re-anodizing/dissolution technique, Fourier-transformed infrared and X-ray photoelectron spectroscopy. These results confirmed formation in FC anodizing solutions of films structurally different from ones grown in FF oxalic acid baths. It was found that the barrier layer of FC alumina films is composed of two layers differing in the dissolution rate. These differences are related to the formation in the FC electrolyte of a barrier layer composed of a more microporous outer part and a thin, non-porous and non-scalloped inner part consisting of aluminum oxide and aluminum fluoride.

  20. Effects of passage barriers on demographics and stability properties of a virtual trout populations

    Science.gov (United States)

    Bret Harvey; Steven Railsback

    2011-01-01

    Habitat fragmentation is widely assumed to have negative effects on populations and communities, but some effects of fragmentation are subtle, difficult to measure and not always negative. For stream fish, barriers to upstream passage, such as waterfalls or culverts with perched outlets, are a common cause of fragmentation. We explored the effects of barriers on a...

  1. Diffusion barriers for Cu metallisation in Si integrated circuits : deposition and related thin film properties

    NARCIS (Netherlands)

    van Nieuwkasteele-Bystrova, Svetlana Nikolajevna

    2004-01-01

    In modern integrated circuits with Cu interconnects a diffusion barrier is used between the dielectric and Cu in order to prevent diffusion of Cu through the dielectrics. The choice of such a barrier requires a material exploration and a study of the material reactivity with both Cu and the

  2. Effect of Gallic acid on mechanical and water barrier properties of zein-oleic acid composite films.

    Science.gov (United States)

    Masamba, Kingsley; Li, Yue; Hategekimana, Joseph; Liu, Fei; Ma, Jianguo; Zhong, Fang

    2016-05-01

    In this study, the effect of gallic acid on mechanical and water barrier properties of zein-oleic acid 0-4 % composite films was investigated. Molecular weight distribution analysis was carried out to confirm gallic acid induced cross linking through change in molecular weight in fraction containing zein proteins. Results revealed that gallic acid treatment increased tensile strength from 17.9 MPa to 26.0 MPa, decreased water vapour permeability from 0.60 (g mm m(-2) h(-1) kPa(-1)) to 0.41 (g mm m(-2) h(-1) kPa(-1)), increased solubility from 6.3 % to 10.2 % and marginally increased elongation at break from 3.7 % to 4.2 % in zein films only. However, gallic acid treatment in zein-oleic composite films did not significantly influence mechanical and water barrier properties and in most instances irrespective of oleic acid concentration, the properties were negatively affected. Results from scanning electron microscopy showed that both gallic acid treated and untreated zein films and composite films containing 3 % oleic acid had a compact and homogeneous structure while those containing 4 % oleic acid had inhomogeneous structure. The findings have demonstrated that gallic acid treatment can significantly improve mechanical and water barrier properties especially in zein films only as opposed to when used in composite films using zein and oleic acid.

  3. The relationship between barriers to change and the work engagement of employees in a South African property management company

    Directory of Open Access Journals (Sweden)

    Elsabé Bell

    2011-09-01

    Full Text Available Orientation: For any organisational change initiative to have a successful outcome, people need to contribute and be engaged in the process. Research purpose: The main objective of the research was to determine the relationship between barriers to change and work engagement. The secondary objectives of the research were to determine whether there are significant relationships between barriers to change, work engagement and demographic variables. Motivation for the study: Exploring and understanding the relationship between barriers to change and work engagement amongst different demographic groups will help organisations to predict which working environments and jobs are amenable to organisational change and which will alleviate, and maybe even eliminate, the negative effects of change. Research design, approach and method: The researchers used a cross-sectional survey research design. They drew a convenience sample of 234 employees (N = 234 from a South African property management company. They administered the Barriers to Change Questionnaire and the Utrecht Work Engagement Scale. Main findings: The results showed a practically significant relationship, with a large effect, between barriers to change and work engagement. In addition, the results showed significant differences between barriers to change and demographic groupings based on home language, ethnicity and organisational level. The results also showed significant differences between work engagement and demographic groupings based on home language, ethnicity and level of education. Practical/managerial implications: Managing barriers to change can increase the work engagement of employees. Contribution/value-add: The research adds to the knowledge about the adverse effects of organisational change initiatives on people.

  4. Effect of lignin on water vapor barrier, mechanical, and structural properties of agar/lignin composite films.

    Science.gov (United States)

    Shankar, Shiv; Reddy, Jeevan Prasad; Rhim, Jong-Whan

    2015-11-01

    Biodegradable composite films were prepared using two renewable resources based biopolymers, agar and lignin alkali. The lignin was used as a reinforcing material and agar as a biopolymer matrix. The effect of lignin concentration (1, 3, 5, and 10wt%) on the performance of the composite films was studied. In addition, the mechanical, water vapor barrier, UV light barrier properties, FE-SEM, and TGA of the films were analyzed. The agar/lignin films exhibited higher mechanical and UV barrier properties along with lower water vapor permeability compared to the neat agar film. The FTIR and SEM results showed the compatibility of lignin with agar polymer. The swelling ratio and moisture content of agar/lignin composite films were decreased with increase in lignin content. The thermostability and char content of agar/lignin composite films increased with increased lignin content. The results suggested that agar/lignin films have a potential to be used as a UV barrier food packaging material for maintaining food safety and extending the shelf-life of the packaged food. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Emulsion properties of pork myofibrillar protein in combination with microbial transglutaminase and calcium alginate under various pH conditions.

    Science.gov (United States)

    Hong, Geun Pyo; Min, Sang-Gi; Chin, Koo Bok

    2012-01-01

    In this study, the effects of microbial transglutaminase (MTG) and calcium alginate (CA) systems in combination with soybean oil on the emulsion properties of porcine myofibrillar protein (MP) were evaluated under various pH conditions. MTG was shown to improve emulsifying capacity and creaming stability, which increased with increasing pH values up to 6.5. The CA did not influence emulsifying capacity, but it improved the creaming stability of the MP-stabilized emulsions. Both MTG and CA enhanced the rheological properties, but their effects on the physical characteristics of the protein evidenced an opposite trend in relation to pH, i.e., the MTG system improved both the emulsion and gelling properties with increasing pH, whereas the CA system was effective when the pH was lowered. By combining the two MP gelling systems, a stable and pH-insensible emulsion could be produced. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Structural, Thermal, Physical, Mechanical, and Barrier Properties of Chitosan Films with the Addition of Xanthan Gum.

    Science.gov (United States)

    de Morais Lima, Maria; Carneiro, Lucia Cesar; Bianchini, Daniela; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa; Prentice, Carlos; Moreira, Angelita da Silveira

    2017-03-01

    Films based on chitosan and xanthan gum were prepared using casting technique aiming to investigate the potential of these polymers as packaging materials. Six formulations of films were studied varying the proportion of chitosan and xanthan gum: 100:0 (chitosan:xanthan gum, w/w, C100XG0 film); 90:10 (chitosan:xanthan gum, w/w, C90XG10 film); 80:20 (chitosan:xanthan gum, w/w, C80XG20 film); 70:30 (chitosan:xanthan gum, w/w, C70XG30 film); 60:40 (chitosan:xanthan gum, w/w, C60XG40 film); and 50:50 (chitosan:xanthan gum, w/w, C50XG50 film). The total quantity of solids (chitosan and xanthan gum) in the filmogenic solution was 1.5 g per 100 mL of aqueous solution for all treatments, according to the proportion of each polymer. The films were evaluated by their functional groups, structural, thermal, morphological, physical, mechanical, and barrier properties. All films have presented endothermic peaks in the range of 122 to 175 °C and broad exothermic peaks above 200 °C, which were assigned to the melting temperature and thermal decomposition, respectively. These results demonstrated that films with xanthan gum have the highest T m and Δ m H. The films containing higher content of xanthan gum show also the highest tensile strength and the lowest elongation. Xanthan gum addition did not affect the water vapor permeability, solubility, and moisture of films. This set of data suggests the formation of chitosan-xanthan complexes in the films. © 2017 Institute of Food Technologists®.

  7. Mechanical, barrier and morphological properties of pea starch and peanut protein isolate blend films.

    Science.gov (United States)

    Sun, Qingjie; Sun, Cuixia; Xiong, Liu

    2013-10-15

    Mechanical, barrier and morphological properties of edible films based on blends of Pea starch (PS) and Peanut protein isolate (PPI) plasticized with glycerol (30%, w/w) were investigated. As PPI ratio in PS/PPI blends increased, the thickness of films decreased, the opacity slightly elevated and color intensified. The addition of PPI to the PS film significantly reduced tensile strength from 5.44 MPa to 3.06 MPa, but increased elongation from 28.56% to 98.12% with the incorporation of PPI into PS at 50% level. Film solubility value fell from 22.31% to 9.78% upon the incorporation of PPI ranged from 0 to 50% level. When PPI was added into PS film at 40% level, the WVP and WVTR of the films markedly dropped from 11.18% to 4.19% and 6.16 to 1.95%, respectively. Scanning electron microscopy (SEM) of the surface of films showed that many swollen starch granules were presented in the 100% PS film, while 100% PPI film was observed to have rougher surfaces with presence of pores or cavities. The PS/PPI blend films upon the incorporation of PPI at 20% and 50% level were not homogeneous. However, the smoother film surface was observed in PS/PPI blend films with the addition of PPI at 40% level. SEM image of the cross-sections of the films revealed that the 100% PS film showed a uniform and compact matrix without disruption, and pore formation and 100% PPI film displayed a smooth structure. Rougher and flexible network was shown in blend film with the addition of PPI reaching 40% level. Copyright © 2013. Published by Elsevier Ltd.

  8. Psychometric properties of the Exercise Benefits/Barriers Scale in Mexican elderly women.

    Science.gov (United States)

    Enríquez-Reyna, María Cristina; Cruz-Castruita, Rosa María; Ceballos-Gurrola, Oswaldo; García-Cadena, Cirilo Humberto; Hernández-Cortés, Perla Lizeth; Guevara-Valtier, Milton Carlos

    2017-06-05

    analyze and assess the psychometric properties of the subscales in the Spanish version of the Exercise Benefits/Barriers Scale in an elderly population in the Northeast of Mexico. methodological study. The sample consisted of 329 elderly associated with one of the five public centers for senior citizens in the metropolitan area of Northeast Mexico. The psychometric properties included the assessment of the Cronbach's alpha coefficient, the Kaiser Meyer Olkin coefficient, the inter-item correlation, exploratory and confirmatory factor analysis. in the principal components analysis, two components were identified based on the 43 items in the scale. The item-total correlation coefficient of the exercise benefits subscale was good. Nevertheless, the coefficient for the exercise barriers subscale revealed inconsistencies. The reliability and validity were acceptable. The confirmatory factor analysis revealed that the elimination of items improved the goodness of fit of the baseline scale, without affecting its validity or reliability. the Exercise Benefits/Barriers subscale presented satisfactory psychometric properties for the Mexican context. A 15-item short version is presented with factorial structure, validity and reliability similar to the complete scale. analisar e avaliar as propriedades psicométricas das subescalas que compõem a versão em espanhol da Escala de Benefícios/Barreiras para o Exercício em uma população idosa do nordeste do México. estudo metodológico. A amostra abrangeu 329 idosas adstritas a uma das cinco casas de convivência públicas da área metropolitana do Nordeste mexicano. As propriedades psicométricas incluíram a avaliação do coeficiente alfa de Cronbach, o coeficiente Kaiser-Meyer-Olkin, a correlação inter-itens, análise fatorial exploratória e confirmatória. na análise de componentes principais, foram identificados dois componentes a partir dos 43 itens da escala. O coeficiente de correlação item-total da subescala

  9. Tailoring barrier properties of thermoplastic corn starch-based films (TPCS) by means of a multilayer design.

    Science.gov (United States)

    Fabra, María José; López-Rubio, Amparo; Cabedo, Luis; Lagaron, Jose M

    2016-12-01

    This work compares the effect of adding different biopolyester electrospun coatings made of polycaprolactone (PCL), polylactic acid (PLA) and polyhydroxybutyrate (PHB) on oxygen and water vapour barrier properties of a thermoplastic corn starch (TPCS) film. The morphology of the developed multilayer structures was also examined by Scanning Electron Microscopy (SEM). Results showed a positive linear relationship between the amount of the electrospun coatings deposited onto both sides of the TPCS film and the thickness of the coating. Interestingly, the addition of electrospun biopolyester coatings led to an exponential oxygen and water vapour permeability drop as the amount of the electrospun coating increased. This study demonstrated the versatility of the technology here proposed to tailor the barrier properties of food packaging materials according to the final intended use. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Barrier properties to surrogates of hydrogenated carbon nano-films deposited on PET by plasma-enhanced chemical vapour deposition.

    Science.gov (United States)

    Oliveira, Éder C; Echegoyen, Yolanda; Nerin, Cristina; Cruz, Sandra A

    2014-01-01

    Poly(ethylene terephthalate) resin was contaminated with a series of surrogates using a US Food and Drug Administration protocol. The contaminated samples were coated with two different kinds of hydrogenated amorphous carbon thin films (a-C:H): one with diamond-like hydrogenated amorphous carbon and another with polymer-like hydrogenated carbon (PLCH) phases. To evaluate the barrier properties of the a-C:H films, migration assays were performed using food simulants. After the tests, analysis by gas chromatography with different detectors was carried out. The appearance of the films before and after the migration experiments was studied by field emission scanning electron microscopy. The results showed that a-C:H films have good barrier properties for most of the evaluated compounds, mainly when they are deposited as PLCH phase.

  11. Effects of oregano oil, carvacrol, cinnamaldehyde, and citral on antimicrobial, mechanical and barrier properties of carrot puree films

    Science.gov (United States)

    Wang, Xinwei; Liu, Huan; Wei, Jing; Ma, Zhongsu

    2011-02-01

    The effects against staphfloccus aureus and escherichia coli of oregano oil, carvacrol, cinnamaldehyde, and citral in chitosan-corn starch-gelatin-carrot puree films at 0.5% to 3% (w/w) concentrations were investigated along with the mechanical and barrier properties of the films. The presence of oregano oil, carvacrol, cinnamaldehyde, and citral did not change the good oxygen barrier of the films, but did significantly modify tensile properties and water vapor permeability, and made films darker. The data also show that the antimicrobial activities were in the following order: cinnamaldehyde > carvacrol > oregano oil > citral. Moreover, the antimicrobial films were more effective against staphfloccus aureus than against the escherichia coli. This study showed that oregano oil, carvacrol, cinnamaldehyde, and citral, especially the first three, could be used to prepare antimicrobial edible films for food applications.

  12. Microbial community assembly in an evolving ecosystem : Ecological succession and functional properties of soil microbes

    NARCIS (Netherlands)

    Dini Andreote, Francisco

    2016-01-01

    Thema’s omtrent “gemeenschapssamenstelling” en “ecologische successie in bodems” zijn traditionele concepten binnen de ecologie, doch minder gewaardeerd in bodemmicrobiologie. Dit proefschrift is gericht op integratie van deze thema’s in microbiële ecologie door gebruik te maken van een natuurlijk

  13. PHYSICOCHEMICAL PROPERTIES AS PREDICTORS OF ORGANIC CHEMICAL EFFECTS ON SOIL MICROBIAL RESPIRATION

    Science.gov (United States)

    Structure-activity analysis was used to evaluate the effects of 19 hazardous organic chemicals on microbial respiration in two slightly acidic soils (a Captina silt loam from Roane County Tennessee, and a McLaurin sandy loam from Stone County, Mississippi), both low in organic ca...

  14. Influence of the voltage polarity on the properties of a nanosecond surface barrier discharge in atmospheric-pressure air

    International Nuclear Information System (INIS)

    Nudnova, M. M.; Aleksandrov, N. L.; Starikovskii, A. Yu.

    2010-01-01

    The properties of a surface barrier discharge in atmospheric-pressure air at different polarities of applied voltage were studied experimentally. The influence of the voltage polarity on the spatial structure of the discharge and the electric field in the discharge plasma was determined by means of spectroscopic measurements. It is found that the energy deposited in the discharge does not depend on the voltage polarity and that discharges of positive polarity are more homogenous and the electric fields in them are higher.

  15. Roll-to-roll DBD plasma pretreated polyethylene web for enhancement of Al coating adhesion and barrier property

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haibao; Li, Hua; Fang, Ming; Wang, Zhengduo; Sang, Lijun; Yang, Lizhen; Chen, Qiang, E-mail: lppmchenqiang@hotmail.com

    2016-12-01

    Graphical abstract: The images of Al coating adhesion testes for (a) untreated and (b) roll-to-roll DBD plasma treated PE. - Highlights: • Over three-months ageing a high surface energy was still existed in roll-to-roll DBD plasma-treated PE surface. • The adhesion and barrier property of Al-coated PE web were greatly improved. • The mechanism of plasma grafting to improve the properties of Al-coated PE web was found. - Abstract: In this paper the roll-to-roll atmospheric dielectric barrier discharge (DBD) was used to pre-treat polyethylene (PE) web surface before the conventional thermal evaporation aluminum (Al) was performed as a barrier layer. We emphasized the plasma environment effect based on the inlet three kinds of reactive monomers. The cross hatch test was employed to assess the Al coating adhesion; and the oxygen transmission rate (OTR) was used to evaluate gas barrier property. The results showed that after roll-to-roll DBD plasma treatment all Al coatings adhered strongly on PE films and were free from pinhole defects with mirror morphology. The OTR was reduced from 2673 cm{sup 3}/m{sup 2} day for Al-coated original PE to 138 cm{sup 3}/m{sup 2} day for Al-coated allyamine (C{sub 3}H{sub 7}N) modified PE. To well understand the mechanism the chemical compositions of the untreated and DBD plasma pretreated PE films were analyzed by X-ray photoelectron spectroscopy (XPS). The surface topography was characterized by atomic force microscopy (AFM). For the property of surface energy the water contact angle measurement was also carried out in the DBD plasma treated samples with deionized water.

  16. Roll-to-roll DBD plasma pretreated polyethylene web for enhancement of Al coating adhesion and barrier property

    International Nuclear Information System (INIS)

    Zhang, Haibao; Li, Hua; Fang, Ming; Wang, Zhengduo; Sang, Lijun; Yang, Lizhen; Chen, Qiang

    2016-01-01

    Graphical abstract: The images of Al coating adhesion testes for (a) untreated and (b) roll-to-roll DBD plasma treated PE. - Highlights: • Over three-months ageing a high surface energy was still existed in roll-to-roll DBD plasma-treated PE surface. • The adhesion and barrier property of Al-coated PE web were greatly improved. • The mechanism of plasma grafting to improve the properties of Al-coated PE web was found. - Abstract: In this paper the roll-to-roll atmospheric dielectric barrier discharge (DBD) was used to pre-treat polyethylene (PE) web surface before the conventional thermal evaporation aluminum (Al) was performed as a barrier layer. We emphasized the plasma environment effect based on the inlet three kinds of reactive monomers. The cross hatch test was employed to assess the Al coating adhesion; and the oxygen transmission rate (OTR) was used to evaluate gas barrier property. The results showed that after roll-to-roll DBD plasma treatment all Al coatings adhered strongly on PE films and were free from pinhole defects with mirror morphology. The OTR was reduced from 2673 cm 3 /m 2 day for Al-coated original PE to 138 cm 3 /m 2 day for Al-coated allyamine (C 3 H 7 N) modified PE. To well understand the mechanism the chemical compositions of the untreated and DBD plasma pretreated PE films were analyzed by X-ray photoelectron spectroscopy (XPS). The surface topography was characterized by atomic force microscopy (AFM). For the property of surface energy the water contact angle measurement was also carried out in the DBD plasma treated samples with deionized water.

  17. Barrier properties of lipid bilayers composed of lecithins with odd chain fatty acids

    NARCIS (Netherlands)

    Salvati, S.; Serlupi-Crescenzi, G.; Gier, J. de

    Lecithins with fatty acid chain length of 17 carbon atoms and different degrees of unsaturation were synthesized. The thermotropic behaviour and barrier function of derived liposomal bilayers were studied.

  18. Mechanical, barrier and antimicrobial properties of biodegradable poly(e-caprolactone) nanocomposites

    CSIR Research Space (South Africa)

    Makhado, E

    2015-05-01

    Full Text Available the potential to develop improved barrier packaging materials; however, increasing the antimicrobial activity on composite surfaces is needed for the development of PCL-based advanced packaging materials....

  19. International conference on the performance of engineered barriers. Physical and chemical properties, behaviour and evolution. Short abstracts

    Energy Technology Data Exchange (ETDEWEB)

    Schaefers, Annika; Fahland, Sandra (eds.)

    2014-08-01

    The volume includes the abstracts of the papers presented at the international conference on the performance of engineered barrier systems, their physical and chemical properties, behavior and evolution. The papers cover the topics bentonite buffers, radioactive waste repository safety, geophysical and geochemical property monitoring, repository sealing materials, thermo-hydro-mechanical characterization, gas injection tests, hydration and heating tests, clay-iron interaction experiments, water retention behavior, thermal stability of materials, numerical modeling studies, long-term simulations, thermo-hydrologic phenomena, uncertainty and sensitivity studies, probabilistic assessments, preliminary safety analyses of Gorleben.

  20. Relationships between respiration, chemical and microbial properties of afforested mine soils with different soil texture and tree species: Does the time of incubation matter

    Czech Academy of Sciences Publication Activity Database

    Józefowska, A.; Pietrzykowski, M.; Woś, B.; Cajthaml, T.; Frouz, Jan

    2017-01-01

    Roč. 80, May (2017), s. 102-109 ISSN 1164-5563 Institutional support: RVO:60077344 Keywords : afforested mine soils * soil texture * tree species * chemical properties * microbial properties Subject RIV: DF - Soil Science OBOR OECD: Soil science Impact factor: 2.445, year: 2016

  1. Effects of material properties and speed of compression on microbial survival and tensile strength in diclofenac tablet formulations.

    Science.gov (United States)

    Ayorinde, J O; Itiola, O A; Odeniyi, M A

    2013-03-01

    A work has been done to study the effects of material properties and compression speed on microbial survival and tensile strength in diclofenac tablet formulations. Tablets were produced from three formulations containing diclofenac and different excipients (DC, DL and DDCP). Two types of machines (Hydraulic hand press and single punch press), which compress the tablets at different speeds, were used. The compression properties of the tablets were analyzed using Heckel and Kawakita equations. A 3-dimensional plot was produced to determine the relationship between the tensile strength, compression speed and percentage survival of Bacillus subtilis in the diclofenac tablets. The mode of consolidation of diclofenac was found to depends on the excipient used in the formulation. DC deformed mainly by plastic flow with the lowest Py and Pk values. DL deformed plastically at the initial stage, followed by fragmentation at the later stage of compression, whereas DDCP deformed mainly by fragmentation with the highest Py and Pk values. The ranking of the percentage survival of B. subtilis in the formulations was DDCP > DL > DC, whereas the ranking of the tensile strength of the tablets was DDCP > DL > DC. Tablets produced on a hydraulic hand press with a lower compression speed had a lower percentage survival of microbial contaminants than those produced on a single punch press, which compressed the tablets at a much higher speed. The mode of consolidation of the materials and the speed at which tablet compression is carried out have effects on both the tensile strength of the tablets and the extent of destruction of microbial contaminants in diclofenac tablet formulations.

  2. Transfection of brain capillary endothelial cells in primary culture with defined blood-brain barrier properties.

    Science.gov (United States)

    Burkhart, Annette; Thomsen, Louiza Bohn; Thomsen, Maj Schneider; Lichota, Jacek; Fazakas, Csilla; Krizbai, István; Moos, Torben

    2015-08-07

    Primary brain capillary endothelial cells (BCECs) are a promising tool to study the blood-brain barrier (BBB) in vitro, as they maintain many important characteristics of the BBB in vivo, especially when co-cultured with pericytes and/or astrocytes. A novel strategy for drug delivery to the brain is to transform BCECs into protein factories by genetic modifications leading to secretion of otherwise BBB impermeable proteins into the central nervous system. However, a huge challenge underlying this strategy is to enable transfection of non-mitotic BCECs, taking a non-viral approach. We therefore aimed to study transfection in primary, non-mitotic BCECs cultured with defined BBB properties without disrupting the cells' integrity. Primary cultures of BCECs, pericytes and astrocytes were generated from rat brains and used in three different in vitro BBB experimental arrangements, which were characterised based on a their expression of tight junction proteins and other BBB specific proteins, high trans-endothelial electrical resistance (TEER), and low passive permeability to radiolabeled mannitol. Recombinant gene expression and protein synthesis were examined in primary BCECs. The BCECs were transfected using a commercially available transfection agent Turbofect™ to express the red fluorescent protein HcRed1-C1. The BCECs were transfected at different time points to monitor transfection in relation to mitotic or non-mitotic cells, as indicated by fluorescence-activated cell sorting analysis after 5-and 6-carboxylfluorescein diacetate succinidyl ester incorporation. The cell cultures exhibited important BBB characteristics judged from their expression of BBB specific proteins, high TEER values, and low passive permeability. Among the three in vitro BBB models, co-culturing with BCECs and astrocytes was well suited for the transfection studies. Transfection was independent of cell division and with equal efficacy between the mitotic and non-mitotic BCECs. Importantly

  3. Stability of operational taxonomic units: an important but neglected property for analyzing microbial diversity.

    Science.gov (United States)

    He, Yan; Caporaso, J Gregory; Jiang, Xiao-Tao; Sheng, Hua-Fang; Huse, Susan M; Rideout, Jai Ram; Edgar, Robert C; Kopylova, Evguenia; Walters, William A; Knight, Rob; Zhou, Hong-Wei

    2015-01-01

    The operational taxonomic unit (OTU) is widely used in microbial ecology. Reproducibility in microbial ecology research depends on the reliability of OTU-based 16S ribosomal subunit RNA (rRNA) analyses. Here, we report that many hierarchical and greedy clustering methods produce unstable OTUs, with membership that depends on the number of sequences clustered. If OTUs are regenerated with additional sequences or samples, sequences originally assigned to a given OTU can be split into different OTUs. Alternatively, sequences assigned to different OTUs can be merged into a single OTU. This OTU instability affects alpha-diversity analyses such as rarefaction curves, beta-diversity analyses such as distance-based ordination (for example, Principal Coordinate Analysis (PCoA)), and the identification of differentially represented OTUs. Our results show that the proportion of unstable OTUs varies for different clustering methods. We found that the closed-reference method is the only one that produces completely stable OTUs, with the caveat that sequences that do not match a pre-existing reference sequence collection are discarded. As a compromise to the factors listed above, we propose using an open-reference method to enhance OTU stability. This type of method clusters sequences against a database and includes unmatched sequences by clustering them via a relatively stable de novo clustering method. OTU stability is an important consideration when analyzing microbial diversity and is a feature that should be taken into account during the development of novel OTU clustering methods.

  4. An assessment of gas impact on geological repository. Methodology and material property of gas migration analysis in engineered barrier system

    International Nuclear Information System (INIS)

    Yamamoto, Mikihiko; Mihara, Morihiro; Ooi, Takao

    2004-01-01

    Gas production in a geological repository has potential hazard, as overpressurisation and enhanced release of radionuclides. Amongst data needed for assessment of gas impact, gas migration properties of engineered barriers, focused on clayey and cementitious material, was evaluated in this report. Gas injection experiments of saturated bentonite sand mixture, mortar and cement paste were carried out. In the experiments, gas entry phenomenon and gas outflow rate were observed for these materials. Based on the experimental results, two-phase flow parameters were evaluated quantitatively. A conventional continuum two-phase flow model, which is only practically used multidimensional multi-phase flow model, was applied to fit the experimental results. The simulation results have been in good agreement with the gas entry time and the outflow flux of gas and water observed in the experiments. It was confirmed that application of the continuum two-phase flow model to gas migration in cementitious materials provides sufficient degree of accuracy for assessment of repository performance. But, for sand bentonite mixture, further extension of basic two-phase flow model is needed especially for effect of stress field. Furthermore, gas migration property of other barrier materials, including rocks, but long-term gas injection test, clarification of influence of chemicals environment and large-scale gas injection test is needed for multi-barrier assessment tool development and their verification. (author)

  5. Structure and Barrier Properties of Multinanolayered Biodegradable PLA/PBSA Films: Confinement Effect via Forced Assembly Coextrusion.

    Science.gov (United States)

    Messin, Tiphaine; Follain, Nadège; Guinault, Alain; Sollogoub, Cyrille; Gaucher, Valérie; Delpouve, Nicolas; Marais, Stéphane

    2017-08-30

    Multilayer coextrusion processing was applied to produce 2049-layer film of poly(butylene succinate-co-butylene adipate) (PBSA) confined against poly(lactic acid) (PLA) using forced assembly, where the PBSA layer thickness was about 60 nm. This unique technology allowed to process semicrystalline PBSA as confined polymer and amorphous PLA as confining polymer in a continuous manner. The continuity of PBSA layers within the 80/20 wt % PLA/PBSA layered films was clearly evidenced by atomic force microscopy (AFM). Similar thermal events to the reference films were revealed by thermal studies; indicating no diffusion of polymers during the melt-processing. Mechanical properties were measured for the multilayer film and the obtained results were those expected considering the fraction of each polymer, revealing the absence of delamination in the PLA/PBSA multinanolayer film. The confinement effect induced by PLA led to a slight orientation of the crystals, an increase of the rigid amorphous fraction (RAF) in PBSA with a densification of this fraction without changing film crystallinity. These structural changes allowed to strongly improve the water vapor and gas barrier properties of the PBSA layer into the multilayer film up to two decades in the case of CO 2 gas. By confining the PBSA structure in very thin and continuous layers, it was then possible to improve the barrier performances of a biodegradable system and the resulting barrier properties were successfully correlated to the effect of confinement on the microstructure and the chain segment mobility of the amorphous phase. Such investigation on these multinanolayers of PLA/PBSA with the aim of evidencing relationships between microstructure implying RAF and barrier performances has never been performed yet. Besides, gas and water permeation results have shown that the barrier improvement obtained from the multilayer was mainly due to the reduction of solubility linked to the reduction of the free volume while

  6. Suberin fatty acids isolated from outer birch bark improve moisture barrier properties of cellulose ether films intended for tablet coatings.

    Science.gov (United States)

    Heinämäki, Jyrki; Halenius, Anna; Paavo, Maaja; Alakurtti, Sami; Pitkänen, Pauliina; Pirttimaa, Minni; Paaver, Urve; Kirsimäe, Kalle; Kogermann, Karin; Yliruusi, Jouko

    2015-07-15

    We showed that the addition of suberin fatty acids (SFAs) even at small concentrations significantly improves the water vapor barrier properties of hydroxypropyl methylcellulose (HPMC) films. SFAs were isolated from the outer birch bark using extractive hydrolysis. The effects of SFAs on the film formation of aqueous HPMC were investigated with free films plasticized with polyethylene glycol (PEG 400). Special attention was paid on the physical solid-state, moisture barrier and mechanical stress-strain properties of films intended for tablet film coatings. Topography and surface morphology, glass transition temperature (Tg), tensile strength, Young's modulus, and water vapor permeation (WVP) of films were studied. The addition of SFAs lowered the Tg of films suggesting partial enhancement in film plasticization. The WVP of films decreased with increasing SFAs concentration up to 15% (calculated as a % w/w from a polymer weight). The WVP value for a non-suberized reference film and suberized film plasticized with PEG 400 was 2.13×10(-6) and 0.69[×10(-6) g/(mm(2)×h)×mm/Pa], respectively. The addition of SFAs impaired the mechanical stress-strain properties of HPMC films by reducing the deformation capacity of film. In conclusion, the film properties and performance of aqueous HPMC can be modified by including SFAs in the films. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Mechanical Properties and Durability of Advanced Environmental Barrier Coatings in Calcium-Magnesium-Alumino-Silicate Environments

    Science.gov (United States)

    Miladinovich, Daniel S.; Zhu, Dongming

    2011-01-01

    Environmental barrier coatings are being developed and tested for use with SiC/SiC ceramic matrix composite (CMC) gas turbine engine components. Several oxide and silicate based compositons are being studied for use as top-coat and intermediate layers in a three or more layer environmental barrier coating system. Specifically, the room temperature Vickers-indentation-fracture-toughness testing and high-temperature stability reaction studies with Calcium Magnesium Alumino-Silicate (CMAS or "sand") are being conducted using advanced testing techniques such as high pressure burner rig tests as well as high heat flux laser tests.

  8. Transport Properties of a Kinetic Model for Chemical Reactions without Barriers

    International Nuclear Information System (INIS)

    Alves, Giselle M.; Kremer, Gilberto M.; Soares, Ana Jacinta

    2011-01-01

    A kinetic model of the Boltzmann equation for chemical reactions without energy barrier is considered here with the aim of evaluating the reaction rate and characterizing the transport coefficient of shear viscosity for the reactive system. The Chapman-Enskog solution of the Boltzmann equation is used to compute the chemical reaction effects, in a flow regime for which the reaction process is close to the final equilibrium state. Some numerical results are provided illustrating that the considered chemical reaction without energy barrier can induce an appreciable influence on the reaction rate and on the transport coefficient of shear viscosity.

  9. 12C+16O: Properties of sub-barrier resonance γ-decay

    International Nuclear Information System (INIS)

    Goasduff, A.; Courtin, S.; Haas, F.; Lebhertz, D.; Jenkins, D. G.; Fallis, J.; Ruiz, C.; Hutcheon, D. A.; Amandruz, P.-A.; Davis, C.; Hager, U.; Ottewell, D.; Ruprecht, G.

    2012-01-01

    In a recent experiment performed at Triumf using the Dragon 0° spectrometer and its associated BGO array, the complete γ-decay of the radiative capture channel below the Coulomb barrier has been measured for the first time. This measurement has been performed at two energies E c.m. = 6.6 and 7.2 MeV. A selective contribution of the entrance spins 2 + and 3 − has been evidenced which is consistent with existing results above the barrier.

  10. Effect of annealing temperature on electrical properties of Au/polyvinyl alcohol/n-InP Schottky barrier structure

    International Nuclear Information System (INIS)

    Reddy, V. Rajagopal; Reddy, M. Siva Pratap; Kumar, A. Ashok; Choi, Chel-Jong

    2012-01-01

    In the present work, thin film of polyvinyl alcohol (PVA) is fabricated on n-type InP substrate as an interfacial layer for electronic modification of Au/n-InP Schottky contact. The electrical characteristics of Au/PVA/n-InP Schottky diode are determined at annealing temperature in the range of 100–300 °C by current–voltage (I-V) and capacitance–voltage (C-V) methods. The Schottky barrier height and ideality factor (n) values of the as-deposited Au/PVA/n-InP diode are obtained at room temperature as 0.66 eV (I-V), 0.82 eV (C-V) and 1.32, respectively. Upon annealing at 200 °C in nitrogen atmosphere for 1 min, the barrier height value increases to 0.81 eV (I-V), 0.99 eV (C-V) and ideality factor decreases to 1.18. When the contact is annealed at 300 °C, the barrier height value decreases to 0.77 eV (I-V), 0.96 eV (C-V) and ideality factor increases to 1.22. It is observed that the interfacial layer of PVA increases the barrier height by the influence of the space charge region of the Au/n-InP Schottky junction. The discrepancy between Schottky barrier heights calculated from I-V and C-V measurements is also explained. Further, Cheung's functions are used to extract the series resistance of Au/PVA/n-InP Schottky diode. The interface state density as determined by Terman's method is found to be 1.04 × 10 12 and 0.59 × 10 12 cm −2 eV −1 for the as-deposited and 200 °C annealed Au/PVA/n-InP Schottky diodes. Finally, it is seen that the Schottky diode parameters changed with increase in the annealing temperature. - Highlights: ► Electrical properties of Au/polyvinyl alcohol (PVA)/n-InP structure have been studied. ► The Au/PVA/n-InP Schottky structure showed a good rectifying behavior. ► A maximum barrier height is obtained when the contact is annealed at 200 °C. ► Interface state density found to be 0.59 × 10 12 cm −2 eV −1 for 200 °C annealed contact. ► Significant effect of interface state density and series resistance on electrical

  11. Measurement of interfacial shear mechanical properties in thermal barrier coating systems by a barb pullout method

    International Nuclear Information System (INIS)

    Guo, S.Q.; Mumm, D.R.; Karlsson, A.M.; Kagawa, Y.

    2005-01-01

    A test technique has been developed to facilitate evaluation of the fracture characteristics of coatings and interfaces in thermal barrier coating (TBC) systems. The methodology has particular application in analyzing delamination crack growth, where crack propagation occurs under predominantly mode II loading. The technique has been demonstrated by quantitatively measuring the effective delamination fracture resistance of an electron-beam physical vapor deposition TBC

  12. Skin barrier properties in patients with recessive X-linked ichthyosis

    DEFF Research Database (Denmark)

    Johansen, J D; Ramsing, D; Vejlsgaard, G

    1995-01-01

    Patients with X-linked recessive ichthyosis (RXLI) were studied as a model of the effect of disturbed epidermal lipid composition on skin barrier function. Thirteen patients with RXLI and 15 age- and sex-matched controls were patch-tested with sodium lauryl sulphate (SLS) 0.5% for 24 h. Basal skin...

  13. Anti-browning and barrier properties of edible coatings prepared with electrospraying

    NARCIS (Netherlands)

    Khan, M.K.I.; Cakmak, I.; Tavman, S.; Schutyser, M.A.I.; Schroen, C.G.P.H.

    2014-01-01

    Electrospraying is a novel technique for the application of coating to foods. In this study, thin lipid-based coatings were prepared by electrospraying on model surface and evaluated for their moisture barrier functionality. Sunflower oil and chocolate based coating materials were electrosprayed at

  14. IPE : EVALUATION OF ORTHOTROPIC ELASTIC PROPERTIES AND ITS APPLICATION IN ROADSIDE BARRIERS

    Science.gov (United States)

    2017-12-24

    Roadside barriers are the primary structural safety devices on surface roads. They can be made from any material as long as they can absorb the energy involved in an impact scenario. One material that has that potential is Ipe, which is a hardwood ma...

  15. Effect of antimicrobial on mechanical, barrier and optical properties of corn starch based self-supporting edible film

    Directory of Open Access Journals (Sweden)

    Tanima Chowdhury

    2013-10-01

    Full Text Available Antimicrobials like potassium sorbate, sodium propionate, and benzoic acid were incorporated in corn starch based formulation to investigate their effect on mechanical, water vapour barrier and optical properties of the developed self supporting edible film. The film was prepared by casting technique. When incorporated at 1.40% and above, potassium sorbate decreased the tensile strength (about 22% and increased the elongation (about 55% of control film; whereas, it increased the water vapour permeability by 15% only when added at 2.66%. At 2.66%, benzoic acid reduced the tensile strength by 24% and sodium propionate increased elongation by 17%. These two antimicrobials did not change the water vapour permeability. However, all the three antimicrobials adversely affected the optical properties by decreasing the whiteness index, increasing yellowness index, and reducing the surface gloss, with potassium sorbate showing the maximum effect. Among the three antimicrobials, sodium propionate appeared to be the best with minimum deterioration of film properties.

  16. Improvement of barrier and mechanical properties of whey protein isolate based food packaging films by incorporation of zein nanoparticles as a novel bionanocomposite

    OpenAIRE

    Oymacı, Pelin; Alsoy Altınkaya, Sacide

    2016-01-01

    In this study, whey protein isolate (WPI) based bio-nanocomposite films embedded with zein nanoparticles (ZNP) were prepared by solution casting. Nanoparticles were coated with sodium caseinate to obtain a uniform distribution in the films. The mechanical, water vapor barrier, surface wetting, morphological and viscoelastic properties of the films were investigated. The addition of ZNP significantly improved the water vapor barrier and mechanical properties of the WPI without adversely affect...

  17. Study of phytochemical, anti-microbial, anti-oxidant, and anti-cancer properties of Allium wallichii.

    Science.gov (United States)

    Bhandari, Jaya; Muhammad, BushraTaj; Thapa, Pratiksha; Shrestha, Bhupal Govinda

    2017-02-08

    There is growing interest in the use of plants for the treatment and prevention of cancer. Medicinal plants are currently being evaluated as source of promising anticancer agents. In this paper, we have investigated the anticancer potential of plant Allium wallichii, a plant native to Nepal and growing at elevations of 2300-4800 m. This is the first study of its kind for the plant mentioned. The dried plant was extracted in aqueous ethanol. Phytochemical screening, anti-microbial assay, anti-oxidant assay, cytotoxicity assay and the flow-cytometric analysis were done for analyzing different phytochemicals present, anti-microbial activity, anti-oxidant activity and anti-cancer properties of Allium wallichii. We observed the presence of steroids, terpenoids, flavonoids, reducing sugars and glycosides in the plant extract and the plant showed moderate anti-microbial and anti-oxidant activity. The IC 50 values of Allium wallichii in different cancer cell lines are 69.69 μg/ml for Prostate cancer (PC3) cell line, 55.29 μg/ml for Breast Cancer (MCF-7) cell line and 46.51 μg/ml for cervical cancer (HeLa) cell line as compared to Doxorubicin (0.85 μg/ml). The cell viability assay using FACS showed that the IC 50 value of Allium wallichii for Burkitt's lymphoma (B-Lymphoma) cell line was 3.817 ± 1.99 mg/ml. Allium wallichii can be an important candidate to be used as an anticancer agent. Separation of pure compounds with bioassay guided extraction, spectrometric analysis and subsequent cytotoxicity assay of the pure bioactive compounds from Allium wallichii is highly recommended as the crude extract itself showed promising cytotoxicity.

  18. Characterization of plasma-polymerized 4-vinyl pyridine with silver nanoparticies on poly(ethylene terephthalate) film for anti-microbial properties

    DEFF Research Database (Denmark)

    Jiang, J.; Winther-Jensen, Bjørn; Kjær, Erik Michael

    2006-01-01

    scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Different thicknesses Of poly(4-vinyl pyridine) coating under different plasma polymerization conditions were studied. Silver nanoparticles with diameter around 50nm deposit were precipitated...... on the poly(4-vinyl pyridine) coating by UV irradiation in Silver nitride water solution, in order to enhance the anti-microbial properties. Different kinds of modified PET films were tested for anti-microbial properties against yeast (Debaryomyces hansenii) by using microbiological analyser mu-4200...

  19. Application of manures to mitigate the harmful effects of electrokinetic remediation of heavy metals on soil microbial properties in polluted soils.

    Science.gov (United States)

    Tahmasbian, Iman; Safari Sinegani, Ali Akbar; Nguyen, Thi Thu Nhan; Che, Rongxiao; Phan, Thuc D; Hosseini Bai, Shahla

    2017-12-01

    Ethylenediaminetetraacetic acid (EDTA) used with electrokinetic (EK) to remediate heavy metal-polluted soils is a toxic chelate for soil microorganisms. Therefore, this study aimed to evaluate the effects of alternative organic chelates to EDTA on improving the microbial properties of a heavy metal-polluted soil subjected to EK. Cow manure extract (CME), poultry manure extract (PME) and EDTA were applied to a lead (Pb) and zinc (Zn)-polluted calcareous soil which were subjected to two electric intensities (1.1 and 3.3 v/cm). Soil carbon pools, microbial activity, microbial abundance (e.g., fungal, actinomycetes and bacterial abundances) and diethylenetriaminepentaacetic acid (DTPA)-extractable Pb and Zn (available forms) were assessed in both cathodic and anodic soils. Applying the EK to soil decreased all the microbial variables in the cathodic and anodic soils in the absence or presence of chelates. Both CME and PME applied with two electric intensities decreased the negative effect of EK on soil microbial variables. The lowest values of soil microbial variables were observed when EK was combined with EDTA. The following order was observed in values of soil microbial variables after treating with EK and chelates: EK + CME or EK + PME > EK > EK + EDTA. The CME and PME could increase the concentrations of available Pb and Zn, although the increase was less than that of EDTA. Overall, despite increasing soil available Pb and Zn, the combination of EK with manures (CME or PME) mitigated the negative effects of using EK on soil microbial properties. This study suggested that the synthetic chelates such as EDTA could be replaced with manures to alleviate the environmental risks of EK application.

  20. Characterization of the cell surface properties of drinking water pathogens by microbial adhesion to hydrocarbon and electrophoretic mobility measurements.

    Science.gov (United States)

    Popovici, Jonathan; White, Colin P; Hoelle, Jill; Kinkle, Brian K; Lytle, Darren A

    2014-06-01

    The surface characteristics of microbial cells directly influence their mobility and behavior within aqueous environments. The cell surface hydrophobicity (CSH) and electrophoretic mobility (EPM) of microbial cells impact a number of interactions and processes including aggregation, adhesion to surfaces, and stability of the cells within the aqueous environments. These cell characteristics are unique to the bacterial species and are a reflection of the large diversity of surface structures, proteins, and appendages of microorganisms. CSH and EPM of bacterial cells contribute substantially to the effectiveness of drinking water treatment to remove them, and therefore an investigation of these properties will be useful in predicting their removal through drinking water treatment processes and transport through drinking water distribution systems. EPM and CSH measurements of six microbiological pathogen or surrogate species suspended in phosphate-buffered water are reported in this work. Two strains of Vibrio cholerae were hydrophobic, while three strains of Escherichia coli were hydrophilic. Bacillus cereus was categorized as moderately hydrophobic. The strains of E. coli had the highest (most negative) EPM. Based on the measurements, E. coli species is predicted to be most difficult to remove from water while V. cholerae will be the easiest to remove. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Influence of Gamma Irradiation on Microbial Quality, Biological Properties and Some Chemical Compositions of Propolis and Bee Pollen In Egypt

    International Nuclear Information System (INIS)

    Eltablawy, S.Y.

    2012-01-01

    Propolis and bee pollen may be subjected to microbial contamination as a result of handling and storage, so, the current study was conducted to evaluate the microbial quality and quantity of Egyptian propolis and pollen and to study microbial contamination, antimicrobial activity, antioxidant activity and some chemical properties as amino acid composition and mineral content of irradiated and non-irradiated tested samples.The results showed that most samples were of unsatisfactory microbiological quality where the total bacterial and mold and yeast counts ranged between 6.6x10-6x10 6 CFU/g and 1.2 x 10 3 -3.7x10 3 CFU/g, respectively. Agar disk diffusion method was used for in vitro antimicrobial evaluation of propolis and pollen using water and 70% ethanolic extract against four gram positive, three gram negative bacteria and one yeast pathogens. The results exhibited that ethanolic extract has effective antibacterial activities than water extract. The free radical-scavenging activity of 70% ethanolic extract of the tested samples was determined using 1,1-diphenyl-2-picryl hydrazyl (DPPH). Pollen ethanolic extract showed higher antioxidant activity than propolis ethanolic extract. Amino acid profile of 70% ethanolic extract was determined. The results of the analysis showed the predominant amino acids in propolis and pollen were cystine and leucine, respectively. Mineral analysis of the tested samples was carried out by atomic absorption. The tested minerals were higher in pollen than in propolis except manganese and selenium. Propolis and pollen heavily bacterial and mold contaminated samples were subjected to increasing doses of gamma radiation (1-5 kGy). Exposure to 4 kGy was sufficient for microbial decontamination or reducing the count less than 10 CFU/g with no detectable effect on their antimicrobial activity. The same irradiation dose showed variable effects on amino acids and mineral content of the tested samples. Propolis and pollen have pharmacological

  2. Electrical properties of nanosized non-barrier inhomogeneities in Zn-based metal-semiconductor contacts to InP

    DEFF Research Database (Denmark)

    Clausen, Thomas; Leistiko, Otto

    1998-01-01

    We have found that the electrical properties of carriers across the metal-semiconductor interface for alloyed Zn based metallizations to n- and p-InP are dominated by nanosized non-barrier inhomogeneities. The effective area covered by the nanosized regions is a small fraction of the contact area...... resulting in high values of the specific contact resistance to p-InP. For n(-)-InP, thermionic emission across nanosized inhomogeneities dominates the carrier flow when T-ann > 440 degrees C. (C) 1998 Elsevier Science B.V....

  3. Arsenic compromises conducting airway epithelial barrier properties in primary mouse and immortalized human cell cultures.

    Directory of Open Access Journals (Sweden)

    Cara L Sherwood

    Full Text Available Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4μM [~300 μg/L (ppb] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE cell model we found that both micromolar (3.9 μM and submicromolar (0.8 μM arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-. We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway.

  4. Functional and structural alterations of epithelial barrier properties of rat ileum following X-irradiation

    International Nuclear Information System (INIS)

    Dublineau, I.; Lebrun, F.; Grison, S.; Griffiths, N.M.

    2004-01-01

    Irradiation of the digestive system leads to alterations of the small intestine. We have characterized the disruption of the barrier integrity in rat ileum from 1 to 14 days following irradiation ranging from 6 to 12 Gy. The intestinal permeability to 14 C-mannitol and 3 H-dextran 70,000 was measured in vitro in Ussing chambers. In parallel to these functional studies, immunohistochemical analyses of junctional proteins (ZO-1 and β-catenin) of ileal epithelium were performed by confocal microscopy. Irradiation with 10 Gy induced a marked decrease in epithelial tissue resistance at three days and a fivefold increase in mannitol permeability, without modifications of dextran permeability. A disorganization of the localization for ZO-1 and β-catenin was also observed. At 7 days after irradiation, we observed a recovery of the organization of junctional proteins in parallel to a return of intestinal permeability to control value. In addition to these time-dependent effects, a gradual effect on epithelial integrity of the radiation doses was observed 3 days after irradiation. This study shows a disruption of the integrity of the intestinal barrier in rat ileum following abdominal X-irradiation, depending on the time postirradiation and on the delivered dose. The loss of barrier integrity was characterized by a disorganization of proteins of tight and adherent junctions, leading to increased intestinal permeability to mannitol. (author)

  5. Magnetic properties and potential barrier between crystallites model of MgGa2-xFexO4 ceramics

    Directory of Open Access Journals (Sweden)

    V. A. dos S. Ribeiro

    Full Text Available Abstract The aim of this work was to investigate the magnetic properties and the electrical conductivity temperature dependence associated to the potential barrier between the crystallites model. Gallium and magnesium containing spinel ceramic has low magnetic coercivity and high electrical resistivity. MgGa2-xFexO4 samples (x= 0.01, 0.05, 0.15, 0.25, 0.35 were prepared by solid-state method and sintered at 800 °C for 8 h. X-ray diffraction analysis confirmed the formation of a single phase with compact cubic spinel structure. The magnetic measurements show that the saturation magnetization and remanence of all samples increased with increasing iron concentration. The coercive field decreased up to the concentration x= 0.15, and above x= 0.25 it was observed an increase in the coercive field. Through electrical characterization it was found that the samples presented highly insulating behavior for x= 0.01, and further increase in x above 0.15 gives a semiconductor behavior compatible with the potential barrier between the crystallites model, i.e. fulfills the condition L/2 > LD (crystallite size L in comparison with the Debye length LD, and the conduction is limited by potential barriers between the crystallites.

  6. Effects of earthworms on physicochemical properties and microbial profiles during vermicomposting of fresh fruit and vegetable wastes.

    Science.gov (United States)

    Huang, Kui; Li, Fusheng; Wei, Yongfen; Fu, Xiaoyong; Chen, Xuemin

    2014-10-01

    This study aimed to investigate the effect of earthworms on physicochemical and microbial properties during vermicomposting of fresh fruit and vegetable wastes (FVW) by contrasting two decomposing systems of FVW with and without earthworms for 5weeks. Compared to control treatment (without earthworms), vermicomposting treatment resulted in a rapid decrease of electrical conductivity and losses of total carbon and nitrogen from the 2nd week. Quantitative PCR displayed that earthworms markedly enhanced bacterial and fungal densities, showing the higher values than control, during the whole decomposition process. In addition, denaturing gradient gel electrophoresis combined with sequencing analysis revealed that earthworms pronouncedly modified bacterial and fungal community structures, through broadening the community diversities of Actinobacteria, Bacteroidetes, Proteobacteria, and Ascomycotina. These results suggest that the presence of earthworms promoted the activity and population of bacteria and fungi, and modified their communities, thus altering the decomposition pathway of fresh FVW. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Metal contamination disturbs biochemical and microbial properties of calcareous agricultural soils of the Mediterranean area.

    Science.gov (United States)

    de Santiago-Martín, Ana; Cheviron, Natalie; Quintana, Jose R; González, Concepción; Lafuente, Antonio L; Mougin, Christian

    2013-04-01

    Mediterranean climate characteristics and carbonate are key factors governing soil heavy-metal accumulation, and low organic matter (OM) content could limit the ability of microbial populations to cope with resulting stress. We studied the effects of metal contamination on a combination of biological parameters in soils having these characteristics. With this aim, soils were spiked with a mixture of cadmium, copper, lead, and zinc, at the two limit values proposed by current European legislation, and incubated for ≤12 months. Then we measured biochemical (phosphatase, urease, β-galactosidase, arylsulfatase, and dehydrogenase activities) and microbial (fungal and bacterial DNA concentration by quantitative polymerase chain reaction) parameters. All of the enzyme activities were strongly affected by metal contamination and showed the following inhibition sequence: phosphatase (30-64 %) soils was attributed to the different proportion of fine mineral fraction, OM, crystalline iron oxides, and divalent cations in soil solution. The decrease of fungal DNA concentration in metal-spiked soils was negligible, whereas the decrease of bacterial DNA was ~1-54 % at the lowest level and 2-69 % at the highest level of contamination. The lowest bacterial DNA decrease occurred in soils with the highest OM, clay, and carbonate contents. Finally, regarding the strong inhibition of the biological parameters measured and the alteration of the fungal/bacterial DNA ratio, we provide strong evidence that disturbance on the system, even within the limiting values of contamination proposed by the current European Directive, could alter key soil processes. These limiting values should be established according to soil characteristics and/or revised when contamination is produced by a mixture of heavy metals.

  8. Ecological effects of soil properties and metal concentrations on the composition and diversity of microbial communities associated with land use patterns in an electronic waste recycling region.

    Science.gov (United States)

    Wu, Wencheng; Dong, Changxun; Wu, Jiahui; Liu, Xiaowen; Wu, Yingxin; Chen, Xianbin; Yu, Shixiao

    2017-12-01

    Soil microbes play vital roles in ecosystem functions, and soil microbial communities may be strongly structured by land use patterns associated with electronic waste (e-waste) recycling activities, which can increase the heavy metal concentration in soils. In this study, a suite of soils from five land use types (paddy field, vegetable field, dry field, forest field, and e-waste recycling site) were collected in Longtang Town, Guangdong Province, South China. Soil physicochemical properties and heavy metal concentrations were measured, and the indigenous microbial assemblages were profiled using 16S rRNA high-throughput sequencing and clone library analyses. The results showed that mercury concentration was positively correlated with both Faith's PD and Chao1 estimates, suggesting that the soil microbial alpha diversity was predominantly regulated by mercury. In addition, redundancy analysis indicated that available phosphorus, soil moisture, and mercury were the three major drivers affecting the microbial assemblages. Overall, the microbial composition was determined primarily by land use patterns, and this study provides a novel insight on the composition and diversity of microbial communities in soils associated with e-waste recycling activities. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Nanocrystalline cellulose-dispersed AKD emulsion for enhancing the mechanical and multiple barrier properties of surface-sized paper.

    Science.gov (United States)

    Yang, Luming; Lu, Sheng; Li, Juanjuan; Zhang, Fengshan; Cha, Ruitao

    2016-01-20

    In this study, we employed nanocrystalline cellulose (NCC) as an efficient dispersant to perpare alkyl ketene dimer (AKD) emulsion. The particle size and zeta potential of AKD/NCC emulsion were measured, which were approximately 5 μm and -50 mV, respectively. The surface-sized paper possessed multiple barriers properties. The air permeability of surface-sized paper was 0.29 μm/Pas and the sizing degree reached 42 s when the amount of sizing was 12.58 g/m(2) with a 96.83% decrease and a 40.00%, increase, respectively. Furthermore, the mechanical properties were optimal when the amount of sizing was about 8 g/m(2). AKD/NCC emulsion acted as a good reinforcing agent in surface-sized paper. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Determination of attenuation properties of massive ceramic bricks cladded with mortars containing barite used as protective barrier for radiodiagnostic rooms

    International Nuclear Information System (INIS)

    Barros, Frieda S.; Schelin, Hugo R.; Tilly Junior, Joao G.; Costa, Paulo R.; Nersissian, Denise Y.; Pereira, Marco A.G.

    2001-01-01

    The purpose of this work is to determine the properties of attenuation of the walls built with massive ceramic bricks to be used as protection barriers in environments of Medicine and Dentistry, when submitted to X-ray diagnosis. Massive ceramic bricks are used thoroughly in constructions as a calking element. The properties of attenuation of these materials were obtained starting from the application of the model of Archer to a group of attenuation curves with wide beams generated in the tensions of 70, 80, 100, 120, 140 and 150 kVp. A radiological equipment of constant potential was used in the Laboratory of IEE/USP, two cameras of ionization of 6cm 3 , coupled to two radiation monitors. The results show that for a tension of 100kVp, the thickness of 10cm of wall made with massive ceramic bricks corresponds to 1mm of lead. (author)

  11. Plant species and functional group effects on abiotic and microbial soil properties and plant-soil feedback responses in two grasslands

    NARCIS (Netherlands)

    Bezemer, T.M.; Lawson, C.S.; Hedlund, K.; Edwards, A.R.; Brooks, A.J.; Igual, J.M.; Mortimer, S.R.; Putten, van der W.H.

    2006-01-01

    1 Plant species differ in their capacity to influence soil organic matter, soil nutrient availability and the composition of soil microbial communities. Their influences on soil properties result in net positive or negative feedback effects, which influence plant performance and plant community

  12. Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand.

    Science.gov (United States)

    Jones, Benjamin E H; Haynes, Richard J; Phillips, Ian R

    2011-02-01

    In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tone of alumina produced, about 2 tones of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation. Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tones ha(-1) in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination. Additions of residue mud increased exchangeable Na(+), ESP and the pH, and HCO (3) (-) and Na(+) concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH (4) (+) , K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (2 mm diameter) increased; greatest aggregation occurred where a combination of residue mud and poultry manure were added. Stability of aggregates, as measured by

  13. Silver nanoparticle-loaded chitosan-starch based films: Fabrication and evaluation of tensile, barrier and antimicrobial properties

    International Nuclear Information System (INIS)

    Yoksan, Rangrong; Chirachanchai, Suwabun

    2010-01-01

    The fabrication of silver nanoparticles was accomplished by γ-ray irradiation reduction of silver nitrate in a chitosan solution. The obtained nanoparticles were stable in the solution for more than six months, and showed the characteristic surface plasmon band at 411 nm as well as a positively charged surface with 40.4 ± 2.0 mV. The silver nanoparticles presented a spherical shape with an average size of 20-25 nm, as observed by TEM. Minimum inhibitory concentration (MIC) against E. coli, S. aureus and B. cereus of the silver nanoparticles dispersed in the γ-ray irradiated chitosan solution was 5.64 μg/mL. The silver nanoparticle-loaded chitosan-starch based films were prepared by a solution casting method. The incorporation of silver nanoparticles led to a slight improvement of the tensile and oxygen gas barrier properties of the polysaccharide-based films, with diminished water vapor/moisture barrier properties. In addition, silver nanoparticle-loaded films exhibited enhanced antimicrobial activity against E. coli, S. aureus and B. cereus. The results suggest that silver nanoparticle-loaded chitosan-starch based films can be feasibly used as antimicrobial materials for food packaging and/or biomedical applications.

  14. Using carboxylated cellulose nanofibers to enhance mechanical and barrier properties of collagen fiber film by electrostatic interaction.

    Science.gov (United States)

    Wang, Wenhang; Zhang, Xiuling; Li, Cong; Du, Guanhua; Zhang, Hongjie; Ni, Yonghao

    2018-06-01

    Collagen-based films including casings with a promising application in meat industry are still needed to improve its inferior performance. In the present study, the reinforcement of carboxylated cellulose nanofibers (CNF) for collagen film, based on inter-/intra- molecular electrostatic interaction between cationic acid-swollen collagen fiber and anionic carboxylated CNF, was investigated. Adding CNF decreased the zeta-potential but increased particle size of collagen fiber suspension, with little effect on pH. Furthermore, CNF addition led to a higher tensile strength but a lower elongation, and the water vapor and oxygen barrier properties were improved remarkably. Because the CNF content was 50 g kg -1 or lower, the films had a homogeneous interwoven network, and CNF homogeneously embedded into collagen fiber matrix according to the scanning electron microscopy and atomic force microscopy analysis. Additionally, CNF addition increased film thickness and opacity, as well as swelling rate. The incorporation of CNF endows collagen fiber films good mechanical and barrier properties over a proper concentration range (≤ 50 g kg -1 collagen fiber), which is closely associated with electrostatic reaction of collagen fiber and CNF and, subsequently, the form of the homogenous, compatible spatial network, indicating a potential applications of CNF in collagenous protein films, such as edible casings. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Improving the physical and moisture barrier properties of Lepidium perfoliatum seed gum biodegradable film with stearic and palmitic acids.

    Science.gov (United States)

    Seyedi, Samira; Koocheki, Arash; Mohebbi, Mohebbat; Zahedi, Younes

    2015-01-01

    Stearic and palmitic fatty acids (10%, 20% and 30%, W/W gum) were used to improve the barrier properties of Lepidium perfoliatum seed gum (LPSG) film. The impact of the incorporation of fatty acids into the film matrix was studied by investigating the physical, mechanical, and barrier properties of the films. Addition of stearic and palmitic fatty acids to LPSG films reduced their water vapor permeability (WVP), moisture content, water solubility and water adsorption. Increasing fatty acid concentration from 10% to 30%, reduced the elongation at break (EB). Lower values of tensile strength (TS) and elastic modulus (EM) were obtained in the presence of higher fatty acids concentrations. Incorporation of fatty acids led to production of opaque films and the opacity increased as function of fatty acids concentration. Results showed that moisture content, water solubility and WVP decreased as the chain length of fatty acid increased. Therefore, LPSG-fatty acids composite film could be used for packaging in which a low affinity toward water is needed. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Electrical properties of Schottky barrier diodes fabricated on (001) β-Ga2O3 substrates with crystal defects

    Science.gov (United States)

    Oshima, Takayoshi; Hashiguchi, Akihiro; Moribayashi, Tomoya; Koshi, Kimiyoshi; Sasaki, Kohei; Kuramata, Akito; Ueda, Osamu; Oishi, Toshiyuki; Kasu, Makoto

    2017-08-01

    The electrical properties of Schottky barrier diodes (SBDs) on a (001) β-Ga2O3 substrate were characterized and correlated with wet etching-revealed crystal defects below the corresponding Schottky contacts. The etching process revealed etched grooves and etched pits, indicating the presence of line-shaped voids and small defects near the surface, respectively. The electrical properties (i.e., leakage currents, ideality factor, and barrier height) exhibited almost no correlation with the density of the line-shaped voids. This very weak correlation was reasonable considering the parallel positional relation between the line-shaped voids extending along the [010] direction and the (001) basal plane in which the voids are rarely exposed on the initial surface in contact with the Schottky metals. The distribution of small defects and SBDs with unusually large leakage currents showed similar patterns on the substrate, suggesting that these defects were responsible for the onset of fatal leak paths. These results will encourage studies on crystal defect management of (001) β-Ga2O3 substrates for the fabrication of devices with enhanced performance using these substrates.

  17. Phospholipids fatty acids of drinking water reservoir sedimentary microbial community: Structure and function responses to hydrostatic pressure and other physico-chemical properties.

    Science.gov (United States)

    Chai, Bei-Bei; Huang, Ting-Lin; Zhao, Xiao-Guang; Li, Ya-Jiao

    2015-07-01

    Microbial communities in three drinking water reservoirs, with different depth in Xi'an city, were quantified by phospholipids fatty acids analysis and multivariate statistical analysis was employed to interpret their response to different hydrostatic pressure and other physico-chemical properties of sediment and overlying water. Principle component analyses of sediment characteristics parameters showed that hydrostatic pressure was the most important effect factor to differentiate the overlying water quality from three drinking water reservoirs from each other. NH4+ content in overlying water was positive by related to hydrostatic pressure, while DO in water-sediment interface and sediment OC in sediment were negative by related with it. Three drinking water reservoir sediments were characterized by microbial communities dominated by common and facultative anaerobic Gram-positive bacteria, as well as, by sulfur oxidizing bacteria. Hydrostatic pressure and physico-chemical properties of sediments (such as sediment OC, sediment TN and sediment TP) were important effect factors to microbial community structure, especially hydrostatic pressure. It is also suggested that high hydrostatic pressure and low dissolved oxygen concentration stimulated Gram-positive and sulfate-reducing bacteria (SRB) bacterial population in drinking water reservoir sediment. This research supplied a successful application of phospholipids fatty acids and multivariate analysis to investigate microbial community composition response to different environmental factors. Thus, few physico-chemical factors can be used to estimate composition microbial of community as reflected by phospholipids fatty acids, which is difficult to detect.

  18. The Use of Feature Parameters to Asses Barrier Properties of ALD coatings for Flexible PV Substrates

    International Nuclear Information System (INIS)

    Blunt, Liam; Fleming, Leigh; Elrawemi, Mohamed; Robbins, David

    2014-01-01

    This paper reports on the recent work carried out as part of the EU funded NanoMend project. The project seeks to develop integrated process inspection, cleaning, repair and control systems for nano-scale thin films on large area substrates. In the present study flexible photovoltaic films have been the substrate of interest. Flexible PV films are the subject of significant development at present and the latest films have efficiencies at or beyond the level of Si based rigid PV modules. These flexible devices are fabricated on polymer film by the repeated deposition, and patterning, of thin layer materials using roll-to-roll processes, where the whole film is approximately 3um thick prior to encapsulation. Whilst flexible films offer significant advantages in terms of mass and the possibility of building integration (BIPV) they are at present susceptible to long term environmental degradation as a result of water vapor transmission through the barrier layers to the CIGS (Copper Indium Gallium Selenide CuIn x Ga (1-x) Se 2 ) PV cells thus causing electrical shorts and efficiency drops. Environmental protection of the GIGS cell is provided by a thin (40nm) barrier coating of Al 2 O 3 . The highly conformal aluminium oxide barrier layer is produced by atomic layer deposition (ALD) where, the ultra-thin Al 2 O 3 layer is deposited onto polymer thin films before these films encapsulate the PV cell. The surface of the starting polymer film must be of very high quality in order to avoid creating defects in the device layers. Since these defects reduce manufacturing yield, in order to prevent them, a further thin polymer coating (planarization layer) is generally applied to the polymer film prior to deposition. The presence of surface irregularities on the uncoated film can create defects within the nanometre-scale, aluminium oxide, barrier layer and these are measured and characterised. This paper begins by reporting the results of early stage measurements conducted to

  19. The influence of fast neutron irradiation on the noise properties of silicon surface-barrier detectors

    International Nuclear Information System (INIS)

    Dabrowski, W.; Korbel, K.

    1988-01-01

    The susceptibility to the fast neutron irradiation of silicon surface-barrier detectors has been investigated. It was shown that the 1/f-noise decreases substantially with increasing fluence in the range from 10 10 n/cm 2 to 10 11 n/cm 2 . The deterioration of the detector performance is caused mainly by the positively-charged defects induced by the radiation. The critical value of the neutron fluence, at which the detector performance begins to be worsened was also determined. 5 refs., 5 figs. (author)

  20. Properties of stabilized MgB2 composite wire with Ti barrier

    International Nuclear Information System (INIS)

    Kovac, P; Husek, I; Melisek, T; Holubek, T

    2007-01-01

    Stabilized four-filament in situ MgB 2 /Ti/Cu/Monel composite wire was produced by the rectangular wire-in-tube (RWIT) technique. 10 wt% of nanosize SiC was added into the Mg-B powder mixture, which was packed into the Ti/Cu and Monel tubes, respectively. The assembled composite was two-axially rolled into wire and/or tape form and sintered at temperatures of 650-850 deg. C/0.5 h. Stabilized MgB 2 wire with Ti barrier is studied in terms of field-dependent transport critical current density, effects of filament size reduction and thermal stability

  1. Bridging adhesion and barrier properties with functional dispersions : towards waterborne anti-corrosion coatings

    NARCIS (Netherlands)

    Soer, W.J.

    2008-01-01

    The successful preparation of waterborne anti-corrosion coatings based on maleic anhydride containing copolymers is described in this thesis. To obtain good anticorrosion coatings, three different properties should be present in a coating system; they should display good mechanical properties, good

  2. Improving Dispersion and Barrier Properties of Polyketone/Graphene Nanoplatelet Composites via Noncovalent Functionalization Using Aminopyrene.

    Science.gov (United States)

    Cho, Jaehyun; Jeon, Ikseong; Kim, Seong Yun; Lim, Soonho; Jho, Jae Young

    2017-08-23

    A series of polyketone (PK) nanocomposite films with varying content of noncovalently functionalized graphene nanoplatelet with 1-aminopyrene (GNP/APy) is prepared by solution blending with a solvent of hexafluoro-2-propanol. GNP/APy, prepared by a facile method, can effectively induce specific interaction such as hydrogen bonding between the amine functional group of GNP/APy and the carbonyl functional group of the PK matrix. With comparison of GNP and GNP/Py as reference materials, intensive investigation on filler-matrix interaction is achieved. In addition, the dispersion state of the functionalized GNP (f-GNPs; GNP/Py and GNP/APy) in the PK matrix is analyzed by three-dimensional nondestructive X-ray microcomputed tomography, and the increased dispersion state of those fillers results in significant improvement in the water vapor transmission rate (WVTR). The enhancement in WVTR of the PK/GNP/APy nanocomposite film at 1 wt % loading of filler leads to a barrier performance approximately 2 times larger compared to that of PK/GNP nanocomposite film and an approximately 92% reduction in WVTR compared to the case of pristine PK film. We expect that this facile method of graphene functionalization to enhance graphene dispersibility as well as interfacial interaction with the polymer matrix will be widely utilized to expand the potential of graphene materials to barrier film applications.

  3. Application of microbial biocementation to improve the physico-mechanical properties of cement mortar

    Directory of Open Access Journals (Sweden)

    S.A. Abo-El-Enein

    2013-04-01

    Full Text Available Calcite is one of the most common and wide spread mineral on Earth constituting 4 wt% of the Earth’s crust. It is naturally found in extensive sedimentary rock masses, as lime stone marble and calcareous sandstone in marine, fresh water and terrestrial environments. Calcium carbonate is one of the most well known mineral that bacteria deposit by the phenomenon called biocementation or microbiologically induced calcite precipitation (MICP. Such deposits have recently emerged as promising binders for protecting and consolidating various building materials. Microbially enhanced calcite precipitation on concrete or mortar has become an important area of research regarding construction materials. This study describes a method of strength and water absorption improvement of cement–sand mortar by the microbiologically induced calcium carbonate precipitation. A moderately alkalophilic aerobic Sporosarcina pasteurii was incorporated at different cell concentrations with the mixing water. The study showed that a 33% increase in 28 days compressive strength of cement mortar was achieved with the addition of about one optical density (1 OD of bacterial cells with mixing water. The strength and water absorption improvement are due to the growth of calcite crystals within the pores of the cement–sand matrix as indicated from the microstructure obtained from scanning electron microscopy (SEM examination.

  4. Property Evaluation and Damage Evolution of Environmental Barrier Coatings and Environmental Barrier Coated SiC/SiC Ceramic Matrix Composite Sub-Elements

    Science.gov (United States)

    Zhu, Dongming; Halbig, Michael; Jaskowiak, Martha; Hurst, Janet; Bhatt, Ram; Fox, Dennis S.

    2014-01-01

    This paper describes recent development of environmental barrier coatings on SiC/SiC ceramic matrix composites. The creep and fatigue behavior at aggressive long-term high temperature conditions have been evaluated and highlighted. Thermal conductivity and high thermal gradient cyclic durability of environmental barrier coatings have been evaluated. The damage accumulation and complex stress-strain behavior environmental barrier coatings on SiCSiC ceramic matrix composite turbine airfoil subelements during the thermal cyclic and fatigue testing of have been also reported.

  5. Hydro-mechanical properties of the red salt clay (T4) - Natural analogue of a clay barrier

    International Nuclear Information System (INIS)

    Minkley, W.; Popp, T.; Salzer, K.; Gruner, M.; Boettge, V.

    2010-01-01

    Document available in extended abstract form only. Long-term storage of high-level radioactive waste in deep geologic formations is worldwide the only accepted solution to warranty long term safety. Besides clay and crystalline rocks, salt is one of the potential host-rock candidates, mainly favored in Germany. As salts rocks are highly soluble their barrier integrity against water inflow from the cap rock is questionable. Argillaceous cap rocks or intercalated clay layers may act as protective shield in the hanging wall above a repository, thus providing a multi-barrier system. The aims of our study are twofold: 1) to characterize the mineralogical, hydraulic and rock-mechanical properties of the so-called Red Salt Clay (T4) as natural analogue of a clay barriers represented by different states of induration corresponding to various depth of burial diagenesis; 2) to demonstrate the favoured barrier properties of an argillaceous layer in the top of a salt formation undergoing dynamic processes such as rock bursts. The so-called Red Salt Clay (T4) is deposited as clay rich clastic sediment at the base of the Aller-series forming a persistent lateral layer above the lower Zechstein-series. The thickness of the clay-formation becomes smaller with decreasing distance from the border of the basin, i.e. from ∼15 m at Rossleben, over 7 m at Bernburg to 3.5 m at Zielitz, all in Saxony-Anhalt, D). The mineralogical composition of the Red Salt Clay varies, e.g. average composition for the Teutschenthal area: clay minerals 54% (Chlorite: 8%; Illite/Muscovite: 46%); quartz: 22%; anhydrite: 15%; accessory gypsum; Halite: 6%, Hematite: ∼ 2%). The geochemical and mineralogical composition of the Red Salt Clay represents a final state of natural salt-clay-systems, thus standing as a natural analogue for bentonite-based sealing systems in contact with high-saline solutions (e.g. saturated NaCl-solution, solutions with various Mg 2+ -, K + -, SO 4 2- - concentrations). The

  6. Influence of binder type and process parameters on the compression properties and microbial survival in diclofenac tablet formulations

    Directory of Open Access Journals (Sweden)

    John Oluwasogo Ayorinde

    2011-12-01

    Full Text Available The influence of binder type and process parameters on the compression properties and microbial survival in diclofenac tablet formulations were studied using a novel gum from Albizia zygia. Tablets were produced from diclofenac formulations containing corn starch, lactose and dicalcium phosphate. Formulations were analyzed using the Heckel and Kawakita plots. Determination of microbial viability in the formulations was done on the compressed tablets of both contaminated and uncontaminated tablets prepared from formulations. Direct compression imparted a higher plasticity on the materials than the wet granulation method. Tablets produced by wet granulation presented with a higher crushing strength than those produced by the direct compression method. Significantly higher microbial survival (pA influência do tipo de ligante e os parâmetros do processo de propriedades de compressão e sobrevivência microbiana em comprimidos de diclofenaco foram estudados utilizando uma nova goma de Albizia zygia. Os comprimidos foram produzidos a partir de formulações de diclofenaco contendo amido de milho, lactose e fosfato bicálcico. As formulações foram analisadas usando os gráficos de Heckel e Kawakita. A determinação da viabilidade microbiana nas formulações foi feita nos comprimidos contaminados e não contaminados preparados a partir de formulações. A compressão direta confere maior plasticidade dos materiais do que o método de granulação úmida. Comprimidos produzidos por granulação úmida apresentaram maior força de esmagamento do que aqueles produzidos pelo método de compressão direta. Observou-se sobrevivência significativamente maior (p<0,05 em formulações preparadas por compressão direta. A sobrevivência percentual dos esporos de Bacillus subtilis diminuiu com o aumento da concentração do agregante. O estudo mostrou que a goma de Albizia é capaz de conferir maior plasticidade aos materiais e apresentou maior redução da

  7. Predictive Models of Nanotoxicity: Relationship of Physicochemical Properties to Particle Movement Through Biological Barriers

    Science.gov (United States)

    Understanding the linkage between the physicochemical (PC) properties of nanoparticles (NP) and their activation of biological systems is poorly understood, yet fundamental to predicting nanotoxicity, idenitifying mode of actions and developing appropriate and effective regul...

  8. Composite films of arabinoxylan and fibrous sepiolite: Morphological, mechanical, and barrier properties

    CSIR Research Space (South Africa)

    Sarossy, Z

    2012-06-01

    Full Text Available Hemicelluloses represent a largely unutilized resource for future bioderived films in packaging and other applications. However, improvement of film properties is needed in order to transfer this potential into reality. In this context, sepiolite, a...

  9. Physico-chemical, microbial and sensory properties of kunu zaki beverage sweetened with black velvet tamarind (Dialium guineense

    Directory of Open Access Journals (Sweden)

    A. O. Dauda

    2017-01-01

    Full Text Available This work determined the physicochemical, microbial and sensory characteristics of kunu zaki sweetened with black velvet tamarind (Dialium guinnense flour. The outer covering and seed of black velvet was removed while the pulp was pulverized to obtain the flour. The tamarind pulp was analysed for its proximate and sugar contents. Kunu zaki was prepared according to standard method and 10, 20, 30, 40 and 50 g of the black velvet pulp was added to 1000 ml each of kunu zaki along with a control sample. The kunu zaki samples were stored at refrigeration temperature (4 ºC for a period of 5 days. The physico-chemical properties (pH, ºbrix, total titratable acidity, color, beta-carotene and vitamin C, microbial load and sensory attributes of the kunu zaki were analysed. The black velvet tamarind pulp had 42.01 g/100 g of total solid. The addition of black velvet tamarind (Dialium guinnense to kunu zaki lowered the pH, thereby improving the keeping quality of the kunu zaki samples. The pH of kunu zaki ranged from 2.69-4.15 while the titratable acidity ranged from 5.44-10.06 %, the beta-carotene and vitamin C content were high with a range of 3.10–36.6 mg/100 g and 4.73–47.25 mg/100 g respectively. The bacterial count ranged from 1-8.8 × 103 cfu/mL and a fungal count of 1-4.9 × 103 cfu/mL. Kunu zaki with 50 g of black velvet tamarind was the most preferred in terms of taste, appearance, aroma and general acceptability.

  10. Investigating the effect of aqueous extracts of basil and savory on antioxidant activity, microbial and sensory properties of probiotic yogurt.

    Science.gov (United States)

    Mosiyani, Zohreh Ghaleh; Pourahmad, Rezvan; Eshaghi, Mohammad Reza

    2017-01-01

    The low viability of probiotics causes the short shelf life of fermented products. Therefore compounds which prolong the viability of probiotic bacteria can increase or at least maintain the health- benefiting properties of these products. On the other hand, the addition of antioxidants is one of the methods to increase the shelf life of food products which has recently become more prevalent. In this respect, herbal extracts which are a good source of antioxidants can be appropriate alternative. The aim of this study was  to evaluate the effect of adding basil and savory extracts on antioxidant activity, and on the microbial and organoleptic characteristics of probiotic yogurt. The effect of adding basil extract (8% and 10%) and savory extract (6% and 8%) separately to low fat yogurt (1.5% fat) containing Lactobacillus paracasei subsp. paracasei was investigated. The samples were stored at 4°C. The viability of Lactobacillus paracasei subsp. paracasei, antioxidant activ- ity and sensory properties of probiotic yogurt were evaluated on the 1st, 7th, 14th and 21st days. Basil and savory extracts significantly increased the viability of probiotic bacteria (p 0.05). During storage, there was no significant difference between the organoleptic scores of the samples (p > 0.05), but the taste score did increase significantly (p yogurt.

  11. Effects of heavy metals and soil physicochemical properties on wetland soil microbial biomass and bacterial community structure.

    Science.gov (United States)

    Zhang, Chang; Nie, Shuang; Liang, Jie; Zeng, Guangming; Wu, Haipeng; Hua, Shanshan; Liu, Jiayu; Yuan, Yujie; Xiao, Haibing; Deng, Linjing; Xiang, Hongyu

    2016-07-01

    Heavy metals (HMs) contamination is a serious environmental issue in wetland soil. Understanding the micro ecological characteristic of HMs polluted wetland soil has become a public concern. The goal of this study was to identify the effects of HMs and soil physicochemical properties on soil microorganisms and prioritize some parameters that contributed significantly to soil microbial biomass (SMB) and bacterial community structure. Bacterial community structure was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). Relationships between soil environment and microorganisms were analyzed by correlation analysis and redundancy analysis (RDA). The result indicated relationship between SMB and HMs was weaker than SMB and physicochemical properties. The RDA showed all eight parameters explained 74.9% of the variation in the bacterial DGGE profiles. 43.4% (contain the variation shared by Cr, Cd, Pb and Cu) of the variation for bacteria was explained by the four kinds of HMs, demonstrating HMs contamination had a significant influence on the changes of bacterial community structure. Cr solely explained 19.4% (pstructure, and Cd explained 17.5% (pstructure changes. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Transition phenomena and thermal transport property in LHD plasmas with an electron internal transport barrier

    International Nuclear Information System (INIS)

    Shimozuma, T.; Kubo, S.; Idei, H.

    2005-01-01

    Two kinds of improved core confinement were observed during centrally focused Electron Cyclotron Heating (ECH) into plasmas sustained by Counter (CNTR) and Co Neutral Beam Injections (NBI) in the Large Helical Device (LHD). One shows transition phenomena to the high-electron-temperature state and has a clear electron Internal Transport Barrier (eITB) in CNTR NBI plasma. Another has no clear transition and no ECH power threshold, but shows a broad high temperature profiles with moderate temperature gradient, which indicates the improved core confinement with additional ECH in Co NBI plasma. The electron heat transport characteristics of these plasmas were directly investigated by using the heat pulse propagation excited by Modulated ECH (MECH). The difference of the features could be caused by the existence of the m/n=2/1 rational surface or island determined by the direction of NBI beam-driven current. (author)

  13. Transition phenomena and thermal transport properties in LHD plasmas with an electron internal transport barrier

    International Nuclear Information System (INIS)

    Shimozuma, T.; Kubo, S.; Idei, H.; Inagaki, S.; Tamura, N.; Tokuzawa, T.; Morisaki, T.; Watanabe, K.Y.; Ida, K.; Yamada, I.; Narihara, K.; Muto, S.; Yokoyama, M.; Yoshimura, Y.; Notake, T.; Ohkubo, K.; Seki, T.; Saito, K.; Kumazawa, R.; Mutoh, T.; Watari, T.; Komori, A.

    2005-01-01

    Two types of improved core confinement were observed during centrally focused electron cyclotron heating (ECH) into plasmas sustained by counter (CNTR) and Co neutral beam injections (NBI) in the Large Helical Device. The CNTR NBI plasma displayed transition phenomena to the high-electron-temperature state and had a clear electron internal transport barrier, while the Co NBI plasma did not show a clear transition or an ECH power threshold but showed broad high temperature profiles with moderate temperature gradient. This indicated that the Co NBI plasma with additional ECH also had an improved core confinement. The electron heat transport characteristics of these plasmas were directly investigated using heat pulse propagation excited by modulated ECH. These effects appear to be related to the m/n = 2/1 rational surface or the island induced by NBI beam-driven current

  14. Gas barrier properties of titanium oxynitride films deposited on polyethylene terephthalate substrates by reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Lin, M.-C. [Department of Materials Science and Engineering, National ChungHsin University, 250, Kuo-Kung Road, 40227 Taichung, Taiwan (China); Chang, L.-S. [Department of Materials Science and Engineering, National ChungHsin University, 250, Kuo-Kung Road, 40227 Taichung, Taiwan (China)], E-mail: lschang@dragon.nchu.edu.tw; Lin, H.C. [Department of Materials Science and Engineering, National Taiwan University, 1, Roosevelt Road, Sec. 4, 106 Taipei, Taiwan (China)

    2008-03-30

    Titanium oxynitride (TiN{sub x}O{sub y}) films were deposited on polyethylene terephthalate (PET) substrates by means of a reactive radio frequency (RF) magnetron sputtering system in which the power density and substrate bias were the varied parameters. Experimental results show that the deposited TiN{sub x}O{sub y} films exhibited an amorphous or a columnar structure with fine crystalline dependent on power density. The deposition rate increases significantly in conjunction as the power density increases from 2 W/cm{sup 2} to 7 W/cm{sup 2}. The maximum deposition rate occurs, as the substrate bias is -40 V at a certain power densities chosen in this study. The film's roughness slightly decreases with increasing substrate bias. The TiN{sub x}O{sub y} films deposited at power densities above 4 W/cm{sup 2} show a steady Ti:N:O ratio of about 1:1:0.8. The water vapor and oxygen transmission rates of the TiN{sub x}O{sub y} films reach values as low as 0.98 g/m{sup 2}-day-atm and 0.60 cm{sup 3}/m{sup 2}-day-atm which are about 6 and 47 times lower than those of the uncoated PET substrate, respectively. These transmission rates are comparable to those of DLC, carbon-based and Al{sub 2}O{sub 3} barrier films. Therefore, TiN{sub x}O{sub y} films are potential candidates to be used as a gas permeation barrier for PET substrate.

  15. Diffusion barrier and adhesion properties of SiO(x)N(y) and SiO(x) layers between Ag/polypyrrole composites and Si substrates.

    Science.gov (United States)

    Horváth, Barbara; Kawakita, Jin; Chikyow, Toyohiro

    2014-06-25

    This paper describes the interface reactions and diffusion between silver/polypyrrole (Ag/PPy) composite and silicon substrate. This composite material can be used as a novel technique for 3D-LSI (large-scale integration) by the fast infilling of through-silicon vias (TSV). By immersion of the silicon wafer with via holes into the dispersed solution of Ag/PPy composite, the holes are filled with the composite. It is important to develop a layer between the composite and the Si substrate with good diffusion barrier and adhesion characteristics. In this paper, SiOx and two types of SiOxNy barrier layers with various thicknesses were investigated. The interface structure between the Si substrate, the barrier, and the Ag/PPy composite was characterized by transmission electron microscopy. The adhesion and diffusion properties of the layers were established for Ag/PPy composite. Increasing thickness of SiOx proved to permit less Ag to transport into the Si substrate. SiOxNy barrier layers showed very good diffusion barrier characteristics; however, their adhesion depended strongly on their composition. A barrier layer composition with good adhesion and Ag barrier properties has been identified in this paper. These results are useful for filling conductive metal/polymer composites into TSV.

  16. Initial studies to assess microbial impacts on nuclear waste disposal

    International Nuclear Information System (INIS)

    Horn, J.M.; Meike, A.; McCright, R.D.; Economides, B.

    1996-01-01

    The impacts of the native and introduced bacteria on the performance of geologic nuclear waste disposal facilities should be evaluated because these bacteria could promote corrosion of repository components and alteration of chemical and hydrological properties of the surrounding engineered and rock barriers. As a first step towards investigating these potentialities, native and introduced bacteria obtained from post-construction Yucca Mountain (YM) rock were isolated under varying conditions, including elevated temperature, low nutrient availability, and the absence of available oxygen. Individual isolates are being screened for activities associated with microbially induced corrosion of metals (MIC). Preliminary determination of growth rates of whole YM microbial communities under varying conditions was also undertaken

  17. Metallic nanoparticles: microbial synthesis and unique properties for biotechnological applications, bioavailability and biotransformation

    NARCIS (Netherlands)

    Pereira, L.; Mehboob, F.; Stams, A.J.M.; Mota, M.M.; Rijnaarts, H.H.M.; Alves, M.M.

    2015-01-01

    The impact of nanotechnology in all areas of science and technology is evident. The expanding availability of a variety of nanostructures with properties in the nanometer size range has sparked widespread interest in their use in biotechnological systems, including the field of environmental

  18. Response of aerobic granular sludge to the long-term presence to nanosilver in sequencing batch reactors: Reactor performance, sludge property, microbial activity and community

    Energy Technology Data Exchange (ETDEWEB)

    Quan, Xiangchun, E-mail: xchquan@bnu.edu.cn; Cen, Yan; Lu, Fang; Gu, Lingyun; Ma, Jingyun

    2015-02-15

    The increasing use of silver nanoparticles (Ag NPs) raises concerns about their potential toxic effects on the environment. Granular shape sludge is a special type of microbial aggregate. The response of aerobic granular sludge (AGS) to the long-term presence of Ag NPs has not been well studied. In this study, AGS was exposed to 5 and 50 mg/L Ag NPs in sequence batch reactors (SBRs) for 69 days, and its response was evaluated based on the sludge properties, microbial activity and community, and reactor performance. The results showed that Ag NPs caused inhibition to microbial activities of AGS from Day 35. At the end of 69 days of Ag NPs exposure, the microbial activity of AGS was significantly inhibited in terms of inhibitions of the ammonia oxidizing rate (33.0%), respiration rate (17.7% and 45.6%) and denitrification rate (6.8%), as well as decreases in the ammonia mono-oxygenase and nitrate reductase activities. During the long-term exposure, the AGS maintained its granular shape and large granule size (approximately 900 μm); the microbial community of AGS slightly changed, but the dominant microbial population remained. Overall, the AGS tolerated the toxicity of Ag NPs well, but a long-term exposure may produce chronic toxicity to the AGS, which is concerning. - Highlights: • AGS demonstrated a good tolerance to the long-term presence of Ag NPs. • Ag NPs did not produce acute toxicity but cause chronic toxicity to AGS. • AGS maintained granular shape, granule size and good settling ability. • The microbial community of AGS slightly changed after long-term Ag NPs exposure.

  19. Response of aerobic granular sludge to the long-term presence to nanosilver in sequencing batch reactors: Reactor performance, sludge property, microbial activity and community

    International Nuclear Information System (INIS)

    Quan, Xiangchun; Cen, Yan; Lu, Fang; Gu, Lingyun; Ma, Jingyun

    2015-01-01

    The increasing use of silver nanoparticles (Ag NPs) raises concerns about their potential toxic effects on the environment. Granular shape sludge is a special type of microbial aggregate. The response of aerobic granular sludge (AGS) to the long-term presence of Ag NPs has not been well studied. In this study, AGS was exposed to 5 and 50 mg/L Ag NPs in sequence batch reactors (SBRs) for 69 days, and its response was evaluated based on the sludge properties, microbial activity and community, and reactor performance. The results showed that Ag NPs caused inhibition to microbial activities of AGS from Day 35. At the end of 69 days of Ag NPs exposure, the microbial activity of AGS was significantly inhibited in terms of inhibitions of the ammonia oxidizing rate (33.0%), respiration rate (17.7% and 45.6%) and denitrification rate (6.8%), as well as decreases in the ammonia mono-oxygenase and nitrate reductase activities. During the long-term exposure, the AGS maintained its granular shape and large granule size (approximately 900 μm); the microbial community of AGS slightly changed, but the dominant microbial population remained. Overall, the AGS tolerated the toxicity of Ag NPs well, but a long-term exposure may produce chronic toxicity to the AGS, which is concerning. - Highlights: • AGS demonstrated a good tolerance to the long-term presence of Ag NPs. • Ag NPs did not produce acute toxicity but cause chronic toxicity to AGS. • AGS maintained granular shape, granule size and good settling ability. • The microbial community of AGS slightly changed after long-term Ag NPs exposure

  20. Cellulose-glycerol-polyvinyl alcohol composite films for food packaging: Evaluation of water adsorption, mechanical properties, light-barrier properties and transparency.

    Science.gov (United States)

    Cazón, Patricia; Vázquez, Manuel; Velazquez, Gonzalo

    2018-09-01

    Nowadays consumers are aware of environmental problems. As an alternative to petrochemical polymers for food packaging, researchers have been focused on biopolymeric materials as raw material. The aim of this study was to evaluate mechanical properties (toughness, burst strength and distance to burst), water adsorption, light-barrier properties and transparency of composite films based on cellulose, glycerol and polyvinyl alcohol. Scanning electron microscopy, spectral analysis (FT-IR and UV-VIS-NIR) and differential scanning calorimetry were performed to explain the morphology, structural and thermal properties of the films. Results showed that polyvinyl alcohol enhances the toughness of films up to 44.30 MJ/m 3 . However, toughness decreases when glycerol concentration is increased (from 23.41 to 10.55 MJ/m 3 ). Water adsorption increased with increasing polyvinyl alcohol concentration up to 222%. Polyvinyl alcohol increased the film thickness. The films showed higher burst strength (up to 12014 g) than other biodegradable films. The films obtained have optimal values of transparency like those values of synthetic polymers. Glycerol produced a UV protective effect in the films, an important effect for food packaging to prevent lipid oxidative deterioration. Results showed that it is feasible to obtain cellulose-glycerol-polyvinyl alcohol composite films with improved properties. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

    OpenAIRE

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability ...

  2. Effect of addition of Versagel on microbial, chemical, and physical properties of low-fat yogurt.

    Science.gov (United States)

    Ramchandran, L; Shah, N P

    2008-09-01

    The objective of this study was to examine the effect of Versagel on the growth and proteolytic activity of Streptococcus thermophilus 1275 and Lactobacillus delbrueckii ssp. bulgaricus 1368 and angiotensin-I converting enzyme inhibitory activity of the peptides generated thereby as well as on the physical properties of low-fat yogurt during a storage period of 28 d at 4 degrees C. Three different types of low-fat yogurts, YV0, YV1, and YV2, were prepared using Versagel as a fat replacer. The fermentation time of the low-fat yogurts containing Versagel was less than that of the control yogurt (YV0). The starter cultures maintained their viability (8.68 to 8.81 log CFU/g of S. thermophilus and 8.51 to 8.81 log CFU/g of L. delbrueckii ssp. bulgaricus) in all the yogurts throughout the storage period. There was some decrease in the pH of the yogurts during storage and an increase in the concentration of lactic acid. However, the proteolytic and ACE-inhibitory potential of the starter cultures was suppressed in the presence of Versagel. On the other hand, the addition of Versagel had a positive impact on the physical properties of the low-fat yogurt, namely, spontaneous whey separation, firmness, and pseudoplastic properties.

  3. Changes in the biomechanical properties of a single cell induced by nonthermal atmospheric pressure micro-dielectric barrier discharge plasma.

    Science.gov (United States)

    Choi, Hyeongwon; Choi, Eun Ha; Kim, Kyung Sook

    2017-10-01

    Mechanical properties of a single cell are closely related to the fate and functions of the cell. Changes in mechanical properties may cause diseases or cell apoptosis. Selective cytotoxic effects of nonthermal atmospheric pressure micro-dielectric barrier discharge (DBD) plasma have been demonstrated on cancer cells. In this work, changes in the mechanical properties of a single cell induced by nonthermal atmospheric pressure micro-DBD plasma were investigated using atomic force microscopy (AFM). Two cervical cancer cell lines (HeLa and SiHa) and normal human fibroblast cells (HFBs) were exposed to micro-DBD plasma for various exposure times. The elasticity of a single cell was determined by force-distance curve measurement using AFM. Young's modulus was decreased by plasma treatment for all cells. The Young's modulus of plasma-treated HeLa cells was decreased by 75% compared to nontreated HeLa cells. In SiHa cells and HFBs, elasticity was decreased slightly. Chemical changes induced by the plasma treatment, which were observed by Raman spectroscopy, were also significant in HeLa cells compared to SiHa cells and HFBs. These results suggested that the molecular changes induced by micro-DBD plasma were related to cell mechanical changes. © 2017 Wiley Periodicals, Inc.

  4. Acetylated rice starches films with different levels of amylose: Mechanical, water vapor barrier, thermal, and biodegradability properties.

    Science.gov (United States)

    Colussi, Rosana; Pinto, Vânia Zanella; El Halal, Shanise Lisie Mello; Biduski, Bárbara; Prietto, Luciana; Castilhos, Danilo Dufech; Zavareze, Elessandra da Rosa; Dias, Alvaro Renato Guerra

    2017-04-15

    Biodegradable films from native or acetylated starches with different amylose levels were prepared. The films were characterized according to the mechanical, water vapor barrier, thermal, and biodegradability properties. The films from acetylated high amylose starches had higher moisture content and water solubility than the native high amylose starch film. However, the acetylation did not affect acid solubility of the films, regardless of the amylose content. Films made from high and medium amylose rice starches were obtained; however low amylose rice starches, whether native or acetylated, did not form films with desirable characteristics. The acetylation decreased the tensile strength and increased the elongation of the films. The acetylated starch-based films had a lower decomposition temperature and higher thermal stability than native starch films. Acetylated starches films exhibited more rapid degradation as compared with the native starches films. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Barrier properties of PE, PP and EVA (nano)composites - The influence of filler type and concentration

    Energy Technology Data Exchange (ETDEWEB)

    Merinska, D.; Kalendova, A. [Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlin, Nam. T. G. Masaryka 275, 762 72 Zlin, Czech Republic and Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Nad Ovcirnou 3685, 760 0 (Czech Republic); Tesarikova, A. [Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlin, Nam. T. G. Masaryka 275, 762 72 Zlin (Czech Republic)

    2014-05-15

    Nanocomposite materials with layered clay used as nanofiller and polyethylene (PE), polypropylene (PP) and copolymer ethylene and vinyl acetate matrix (EVA, the content of VA component 19 wt. %) were prepared by compounding the individual components in Brabender kneader. The MMT Na+ and four types of commercial products such as Nanofil N 5 and N3000, Cloisite 93A and 30B were used as nanofillers. Next to the clays microprecipitated CaHCO{sub 3}, nanosilica and Halloysite tubes were used. The quantity of all the above-mentioned (nano)fillers was 1, 3 and 5 wt. % in relation to the content of montmorillonite. The aim was to evaluate the influence of (nano)filler type and concentration on nanocomposite barrier properties. The morphology of nanocomposite samples was examined by means of XRD analysis illustrated by transmission electronic microscopy TEM. Furthermore, permeability for O{sub 2} and CO{sub 2} were observed.

  6. Electrical and chemical properties of XeCl*(308 nm) exciplex lamp created by a dielectric barrier discharge

    International Nuclear Information System (INIS)

    Baadj, S.; Harrache, Z.; Belasri, A.

    2013-01-01

    The aim of this work is to highlight, through numerical modeling, the chemical and the electrical characteristics of xenon chloride mixture in XeCl* (308 nm) excimer lamp created by a dielectric barrier discharge. A temporal model, based on the Xe/Cl 2 mixture chemistry, the circuit and the Boltzmann equations, is constructed. The effects of operating voltage, Cl 2 percentage in the Xe/Cl 2 gas mixture, dielectric capacitance, as well as gas pressure on the 308-nm photon generation, under typical experimental operating conditions, have been investigated and discussed. The importance of charged and excited species, including the major electronic and ionic processes, is also demonstrated. The present calculations show clearly that the model predicts the optimal operating conditions and describes the electrical and chemical properties of the XeCl* exciplex lamp

  7. Electrical and chemical properties of XeCl*(308 nm) exciplex lamp created by a dielectric barrier discharge

    Energy Technology Data Exchange (ETDEWEB)

    Baadj, S.; Harrache, Z., E-mail: zharrache@yahoo.com; Belasri, A. [Université des Sciences et de la Technologie d’Oran, USTO-MB, Laboratoire de Physique des Plasmas, Matériaux Conducteurs et leurs Application (LPPMCA) (Algeria)

    2013-12-15

    The aim of this work is to highlight, through numerical modeling, the chemical and the electrical characteristics of xenon chloride mixture in XeCl* (308 nm) excimer lamp created by a dielectric barrier discharge. A temporal model, based on the Xe/Cl{sub 2} mixture chemistry, the circuit and the Boltzmann equations, is constructed. The effects of operating voltage, Cl{sub 2} percentage in the Xe/Cl{sub 2} gas mixture, dielectric capacitance, as well as gas pressure on the 308-nm photon generation, under typical experimental operating conditions, have been investigated and discussed. The importance of charged and excited species, including the major electronic and ionic processes, is also demonstrated. The present calculations show clearly that the model predicts the optimal operating conditions and describes the electrical and chemical properties of the XeCl* exciplex lamp.

  8. Electrical and chemical properties of XeCl*(308 nm) exciplex lamp created by a dielectric barrier discharge

    Science.gov (United States)

    Baadj, S.; Harrache, Z.; Belasri, A.

    2013-12-01

    The aim of this work is to highlight, through numerical modeling, the chemical and the electrical characteristics of xenon chloride mixture in XeCl* (308 nm) excimer lamp created by a dielectric barrier discharge. A temporal model, based on the Xe/Cl2 mixture chemistry, the circuit and the Boltzmann equations, is constructed. The effects of operating voltage, Cl2 percentage in the Xe/Cl2 gas mixture, dielectric capacitance, as well as gas pressure on the 308-nm photon generation, under typical experimental operating conditions, have been investigated and discussed. The importance of charged and excited species, including the major electronic and ionic processes, is also demonstrated. The present calculations show clearly that the model predicts the optimal operating conditions and describes the electrical and chemical properties of the XeCl* exciplex lamp.

  9. Effects of variation of oil and zinc oxide type on the gas barrier and mechanical properties of chlorobutyl rubber/epoxidised natural rubber blends

    International Nuclear Information System (INIS)

    Li, Lin; Zhang, Jin; Jo, Jae Ok; Datta, Sanjoy; Kim, Jin Kuk

    2013-01-01

    Highlights: ► A (90:10) blend of CIIR and ENR by weight was used as the base. ► Different process oil and ZnO were used to optimize the gas barrier property. ► The minimum oxygen permeability is obtained using sheet ZnO. - Abstract: In many polymer applications such as inner tire liners and fuel hoses, imparting excellent gas barrier property is of prime importance. Researches in this direction had been done based on a judicious choice of polymer type or a blend thereof and the compounding ingredients. Though butyl rubber has been the polymer of choice because of its excellent gas barrier property, yet researches were targeted to improve the same with further modification in the polymer type and variation in compounding ingredients. In this study, a (90:10) blend of chlorobutyl rubber (CIIR) and Epoxdised Natural Rubber (ENR) by weight was used as the base. Four different types of process oil and three different types of zinc oxide (ZnO) at fixed predetermined concentrations were used to optimize the gas barrier and mechanical properties. In this blend, recycled aromatic oil (RAE) and sheet zinc oxide were effective in imparting the best overall combination of properties. Scanning Electron Microscopic (SEM) studies of ZnO were done to understand the structure property relationship

  10. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles.

    Science.gov (United States)

    Al-Ta'ii, Hassan Maktuff Jaber; Periasamy, Vengadesh; Amin, Yusoff Mohd

    2015-05-21

    Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA) acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0-20 min) of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung's and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung's methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.

  11. Electronic Properties of DNA-Based Schottky Barrier Diodes in Response to Alpha Particles

    Directory of Open Access Journals (Sweden)

    Hassan Maktuff Jaber Al-Ta'ii

    2015-05-01

    Full Text Available Detection of nuclear radiation such as alpha particles has become an important field of research in recent history due to nuclear threats and accidents. In this context; deoxyribonucleic acid (DNA acting as an organic semiconducting material could be utilized in a metal/semiconductor Schottky junction for detecting alpha particles. In this work we demonstrate for the first time the effect of alpha irradiation on an Al/DNA/p-Si/Al Schottky diode by investigating its current-voltage characteristics. The diodes were exposed for different periods (0–20 min of irradiation. Various diode parameters such as ideality factor, barrier height, series resistance, Richardson constant and saturation current were then determined using conventional, Cheung and Cheung’s and Norde methods. Generally, ideality factor or n values were observed to be greater than unity, which indicates the influence of some other current transport mechanism besides thermionic processes. Results indicated ideality factor variation between 9.97 and 9.57 for irradiation times between the ranges 0 to 20 min. Increase in the series resistance with increase in irradiation time was also observed when calculated using conventional and Cheung and Cheung’s methods. These responses demonstrate that changes in the electrical characteristics of the metal-semiconductor-metal diode could be further utilized as sensing elements to detect alpha particles.

  12. Nanostructural morphology of plasticized wheat gluten and modified potato starch composites: relationship to mechanical and barrier properties.

    Science.gov (United States)

    Muneer, Faraz; Andersson, Mariette; Koch, Kristine; Menzel, Carolin; Hedenqvist, Mikael S; Gällstedt, Mikael; Plivelic, Tomás S; Kuktaite, Ramune

    2015-03-09

    In the present study, we were able to produce composites of wheat gluten (WG) protein and a novel genetically modified potato starch (MPS) with attractive mechanical and gas barrier properties using extrusion. Characterization of the MPS revealed an altered chain length distribution of the amylopectin fraction and slightly increased amylose content compared to wild type potato starch. WG and MPS of different ratios plasticized with either glycerol or glycerol and water were extruded at 110 and 130 °C. The nanomorphology of the composites showed the MPS having semicrystalline structure of a characteristic lamellar arrangement with an approximately 100 Å period observed by small-angle X-ray scattering and a B-type crystal structure observed by wide-angle X-ray scattering analysis. WG has a structure resembling the hexagonal macromolecular arrangement as reported previously in WG films. A larger amount of β-sheets was observed in the samples 70/30 and 30/70 WG-MPS processed at 130 °C with 45% glycerol. Highly polymerized WG protein was found in the samples processed at 130 °C versus 110 °C. Also, greater amounts of WG protein in the blend resulted in greater extensibility (110 °C) and a decrease in both E-modulus and maximum stress at 110 and 130 °C, respectively. Under ambient conditions the WG-MPS composite (70/30) with 45% glycerol showed excellent gas barrier properties to be further explored in multilayer film packaging applications.

  13. Study of the properties and biodegradability of polyester/starch blends submitted to microbial attack

    International Nuclear Information System (INIS)

    Vinhas, Gloria M.; Almeida, Yeda M.B. de; Lima, Maria Alice Gomes de Andrade; Santos, Livia Almeida

    2007-01-01

    This work deals with the biodegradation of blends of poly(beta-hydroxybutyrate)/starch and poly(beta-hydroxybutyrate-cohydroxyvalerate)/ starch. The blends were obtained by evaporation of the solvent in the mixture of the polymers in chloroform. Tests were carried out in presence of micro-organisms which acted as biodegradation agents. The blends were consumed as carbon substrate and the production of CO 2 was evaluated in the process. In addition, the polyesters' mechanical properties were reduced by the incorporation of starch in its structure. ( 1 H) NMR and infrared spectroscopy detected some characteristic polyester degradation groups in the polyesters' chemical structure, thus confirming the alteration suffered by it. (author)

  14. Mechanical and barrier properties of maize starch-gelatin composite films: effects of amylose content.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Xiao, Jingdong; Liu, Yaowei; Ding, Junsheng; Zhang, Shaojing; Liu, Anjun

    2017-08-01

    In order to obtain new reinforcing bio-fillers to improve the physicochemical properties of gelatin-based films, three types of maize starch, waxy maize starch (Ap), normal starch (Ns) and high-amylose starch (Al), were incorporated into gelatin film and the resulting film properties were investigated, focusing on the impact of amylose content. The thickness, opacity and roughness of gelatin film increased depending on the amylose content along with the starch concentration. The effects of the three starches on the mechanical properties of gelatin film were governed by amylose content, starch concentration as well as environmental relative humidity (RH). At 75% RH, the presence of Al and Ns in the gelatin matrix increased the film strength but decreased its elongation, while Ap exhibited an inverse effect. Starch addition decreased the oxygen permeability of the film, with the lowest value at 20% Al and Ns. All starches, notably at 30% content, led to a decrease in the water vapor permeability of the film at 90% RH, especially Ns starch. Furthermore, the starches improved the thermal stability of the film to some extent. Fourier transform infrared spectra indicated that some weak intermolecular interactions such as hydrogen bonding occurred between gelatin and starch. Moreover, a high degree of B-type crystallinity of starch was characterized in Gel-Al film by X-ray diffraction. Tailoring the properties of gelatin film by the incorporation of different types of maize starch provides the potential to extend its applications in edible food packaging. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  15. Material properties of plasticized hardwood xylans for potential application as oxygen barrier films.

    Science.gov (United States)

    Gröndahl, Maria; Eriksson, Lisa; Gatenholm, Paul

    2004-01-01

    Free films based on glucuronoxylan isolated from aspen wood were prepared by casting from aqueous solutions and drying in a controlled environment. Addition of xylitol or sorbitol facilitated film formation and thus examination of the material properties of these films. The mechanical properties of the films were evaluated using tensile testing and dynamic mechanical analysis in a controlled ambient relative humidity. The strain at break increased, and the stress at break and Young's modulus of the films decreased with increasing amounts of xylitol and sorbitol due to plasticization. At high amount of plasticizer, it was found that films with xylitol gave lower extensibility. Wide-angle X-ray scattering analysis showed that xylitol crystallized in a distinct phase, which we believe contributes to the more brittle behavior of these films. The effect of the plasticizers on the glass transition temperature was determined using dynamic mechanical analysis and differential scanning calorimetry. An increased amount of plasticizer shifted the glass transition to lower temperatures. The effect of moisture on the properties of plasticized films was investigated using water vapor sorption isotherms and by humidity scans in dynamic mechanical analysis. Sorption isotherms showed a transition from type II to type III when adding plasticizer. The films showed low oxygen permeability and thus have a potential application in food packaging.

  16. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts.

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt.

  17. Enhanced Microbial, Functional and Sensory Properties of Herbal Yogurt Fermented with Korean Traditional Plant Extracts

    Science.gov (United States)

    Joung, Jae Yeon; Lee, Ji Young; Ha, Young Sik; Shin, Yong Kook; Kim, Younghoon; Kim, Sae Hun; Oh, Nam Su

    2016-01-01

    This study evaluated the effects of two Korean traditional plant extracts (Diospyros kaki THUNB. leaf; DK, and Nelumbo nucifera leaf; NN) on the fermentation, functional and sensory properties of herbal yogurts. Compared to control fermentation, all plant extracts increased acidification rate and reduced the time to complete fermentation (pH 4.5). Supplementation of plant extracts and storage time were found to influence the characteristics of the yogurts, contributing to increased viability of starter culture and phenolic compounds. In particular, the increase in the counts of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus was highest (2.95 and 1.14 Log CFU/mL respectively) in DK yogurt. Furthermore, supplementation of the plant extracts significantly influenced to increase the antioxidant activity and water holding capacity and to produce volatile compounds. The higher antioxidant activity and water holding capacity were observed in NN yogurt than DK yogurt. Moreover, all of the sensory characteristics were altered by the addition of plant extracts. Addition of plant extracts increased the scores related to flavor, taste, and texture from plain yogurt without a plant extract, as a result of volatile compounds analysis. Thus, the overall preference was increased by plant extracts. Consequently, supplementation of DK and NN extracts in yogurt enhanced the antioxidant activity and physical property, moreover increased the acceptability of yogurt. These findings demonstrate the possibility of using plant extracts as a functional ingredient in the manufacture of herbal yogurt. PMID:27499669

  18. Properties of alternative microbial hosts used in synthetic biology: towards the design of a modular chassis

    Science.gov (United States)

    Kim, Juhyun; Salvador, Manuel; Saunders, Elizabeth; González, Jaime; Avignone-Rossa, Claudio

    2016-01-01

    The chassis is the cellular host used as a recipient of engineered biological systems in synthetic biology. They are required to propagate the genetic information and to express the genes encoded in it. Despite being an essential element for the appropriate function of genetic circuits, the chassis is rarely considered in their design phase. Consequently, the circuits are transferred to model organisms commonly used in the laboratory, such as Escherichia coli, that may be suboptimal for a required function. In this review, we discuss some of the properties desirable in a versatile chassis and summarize some examples of alternative hosts for synthetic biology amenable for engineering. These properties include a suitable life style, a robust cell wall, good knowledge of its regulatory network as well as of the interplay of the host components with the exogenous circuits, and the possibility of developing whole-cell models and tuneable metabolic fluxes that could allow a better distribution of cellular resources (metabolites, ATP, nucleotides, amino acids, transcriptional and translational machinery). We highlight Pseudomonas putida, widely used in many different biotechnological applications as a prominent organism for synthetic biology due to its metabolic diversity, robustness and ease of manipulation. PMID:27903818

  19. Salt tolerant SUV3 overexpressing transgenic rice plants conserve physicochemical properties and microbial communities of rhizosphere.

    Science.gov (United States)

    Sahoo, Ranjan K; Ansari, Mohammad W; Tuteja, Renu; Tuteja, Narendra

    2015-01-01

    Key concerns in the ecological evaluation of GM crops are undesirably spread, gene flow, other environmental impacts, and consequences on soil microorganism's biodiversity. Numerous reports have highlighted the effects of transgenic plants on the physiology of non-targeted rhizospheric microbes and the food chain via causing adverse effects. Therefore, there is an urgent need to develop transgenics with insignificant toxic on environmental health. In the present study, SUV3 overexpressing salt tolerant transgenic rice evaluated in New Delhi and Cuttack soil conditions for their effects on physicochemical and biological properties of rhizosphere. Its cultivation does not affect soil properties viz., pH, Eh, organic C, P, K, N, Ca, Mg, S, Na and Fe(2+). Additionally, SUV3 rice plants do not cause any change in the phenotype, species characteristics and antibiotic sensitivity of rhizospheric bacteria. The population and/or number of soil organisms such as bacteria, fungi and nematodes were unchanged in the soil. Also, the activity of bacterial enzymes viz., dehydrogenase, invertase, phenol oxidases, acid phosphatases, ureases and proteases was not significantly affected. Further, plant growth promotion (PGP) functions of bacteria such as siderophore, HCN, salicylic acid, IAA, GA, zeatin, ABA, NH3, phosphorus metabolism, ACC deaminase and iron tolerance were, considerably, not influenced. The present findings suggest ecologically pertinent of salt tolerant SUV3 rice to sustain the health and usual functions of the rhizospheric organisms. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Detergent-compatible proteases: microbial production, properties, and stain removal analysis.

    Science.gov (United States)

    Niyonzima, Francois Niyongabo; More, Sunil

    2015-01-01

    Proteases are one of the most important commercial enzymes used in various industrial domains such as detergent and leather industries. The alkaline proteases as well as other detergent-compatible enzymes such as lipases and amylases serve now as the key components in detergent formulations. They break down various stains during fabric washing. The search for detergent-compatible proteases with better properties is a continuous exercise. The current trend is to use detergent-compatible proteases that are stable over a wide temperature range. Although the proteases showing stability at elevated pH have the capacity to be used in detergent formulations, their usage can be significant if they are also stable and compatible with detergent and detergent ingredients, and also able to remove protein stains. Despite the existence of some reviews on alkaline proteases, there is no specification for the use of alkaline proteases as detergent additives. The present review describes the detergent-compatible proteases tested as detergent additives. An overview was provided for screening, optimization, purification, and properties of detergent compatible proteases, with an emphasis on the stability and compatibility of the alkaline proteases with the detergent and detergent compounds, as well as stain removal examination methods.

  1. The use of electrochemical impedance spectroscopy (EIS) in the evaluation of the electrochemical properties of a microbial fuel cell.

    Science.gov (United States)

    Manohar, Aswin K; Bretschger, Orianna; Nealson, Kenneth H; Mansfeld, Florian

    2008-04-01

    Electrochemical impedance spectroscopy (EIS) has been used to determine several electrochemical properties of the anode and cathode of a mediator-less microbial fuel cell (MFC) under different operational conditions. These operational conditions included a system with and without the bacterial catalyst and EIS measurements at the open-circuit potential of the anode and the cathode or at an applied cell voltage. In all cases the impedance spectra followed a simple one-time-constant model (OTCM) in which the solution resistance is in series with a parallel combination of the polarization resistance and the electrode capacitance. Analysis of the impedance spectra showed that addition of Shewanella oneidensis MR-1 to a solution of buffer and lactate greatly increased the rate of the lactate oxidation at the anode under open-circuit conditions. The large decrease of open-circuit potential of the anode increased the cell voltage of the MFC and its power output. Measurements of impedance spectra for the MFC at different cell voltages resulted in determining the internal resistance (R(int)) of the MFC and it was found that R(int) is a function of cell voltage. Additionally, R(int) was equal to R(ext) at the cell voltage corresponding to maximum power, where R(ext) is the external resistance that must be applied across the circuit to obtain the maximum power output.

  2. Bio-prospecting of soil Streptomyces and its bioassay-guided isolation of microbial derived auxin with antifungal properties.

    Science.gov (United States)

    Saravana Kumar, P; Yuvaraj, P; Gabrial Paulraj, M; Ignacimuthu, S; Abdullah Al-Dhabi, N

    2018-06-05

    The present study was aimed to isolate bioactive actinomycetes with antifungal properties. Twenty-seven distinct soil derived actinomycetes were investigated for their antifungal activities. Among these, one isolate exhibited significant antifungal activity. Phenotypic and 16s rRNA gene sequence analysis strongly suggested that the active isolate BG4 belonged to the genus Streptomyces. Further, the chemical investigation of the active extract resulted in the isolation of a major compound and it was structurally elucidated as phenyl acetic acid (PAA). PAA exhibited promising antifungal activity with 100% inhibition, ranging from 31.25 to 25μg/mL. It is to be noted that PAA is naturally occurring and biologically active auxin. In addition, it has also been hypothesized that phytohormone endorsing the source of soil-symbionts has similar pathways for synthesizing compounds and its congeners of host due to horizontal gene transfer. These findings demonstrate that microbially derived phytohormone can be used to treat fungal infections. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  3. Effect of pulsed electric fields on microbial inactivation and physico-chemical properties of whole porcine blood.

    Science.gov (United States)

    Boulaaba, Annika; Egen, Nathalie; Klein, Günter

    2014-04-01

    The objective of this study was to determine the lethal effectiveness of pulsed electric fields on the inactivation of the porcine blood endogenous microflora. Furthermore, the impact of pulsed electric field application on physico-chemical and sensory properties in this medium should be proved. Blood samples from a commercial abattoir in Germany were processed by a continuous pilot plant-pulsed electric field system at electric field strength of 11 kV/cm for treatment times of 163 and 209 µs. The applied pulse frequencies of 134 and 175 Hz correspond to an energy input of 91 and 114 kJ/kg, respectively. In these conditions, the effectiveness of pulsed electric field processing on microbial inactivation was limited: 1.35 log10 CFU/mL reduction of total aerobic plate count (p pulsed electric field-treated blood samples. Pulsed electric field processing leads to a complete hemolysis of the red blood cells, in addition significant decreased L* (lightness), a* (redness) and b* (yellowness) values (p < 0.0001) were observed. Furthermore, changes in the sensory attributes color (changed from red to dark brown) and odor (changed from fresh to musty and tangy) were noticed.

  4. Effect of Microbial Transglutaminase on Ice Cream Heat Resistance Properties – a Short Report

    Directory of Open Access Journals (Sweden)

    Kasprzyk Iwona

    2016-07-01

    Full Text Available The objective of this study was to investigate the effect of the addition of transglutaminase (TG preparation Saprovia L ® (PMT TRADING Co. Ltd, Lodz, Poland on the properties of ice cream with 40 g/kg and 70 g/kg fat content. TG was added at a concentration of 2 U/g protein. We studied the effect of transglutaminase on fresh and 3-month-stored at -25°C ice cream. Ice cream mixes were prepared with 5 g/kg stabilizer. Melting test was performed after thermal shocks until the “1st drop” occurrence. The amount of effluent was measured within the 0-120 min time frame. We evaluated the appearance of the samples and carried out the TPA and compression analysis. The addition of the enzyme has increased the resistance of stored ice cream to repeated thermal shocks.

  5. Harnessing microbial subsurface metal reduction activities to synthesise nanoscale cobalt ferrite with enhanced magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-03-24

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe{sub 2}O{sub 4}) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of {approx} 10{sup 6} erg cm{sup -3} can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than

  6. Harnessing microbial subsurface metal reduction activities to synthesize nanoscale cobalt ferrite with enhanced magnetic properties

    International Nuclear Information System (INIS)

    Coker, Victoria S.; Telling, Neil D.; van der Laan, Gerrit; Pattrick, Richard A.D.; Pearce, Carolyn I.; Arenholz, Elke; Tuna, Floriana; Winpenny, Richard E.P.; Lloyd, Jonathan R.

    2009-01-01

    Nanoscale ferrimagnetic particles have a diverse range of uses from directed cancer therapy and drug delivery systems to magnetic recording media and transducers. Such applications require the production of monodisperse nanoparticles with well-controlled size, composition, and magnetic properties. To fabricate these materials purely using synthetic methods is costly in both environmental and economical terms. However, metal-reducing microorganisms offer an untapped resource to produce these materials. Here, the Fe(III)-reducing bacterium Geobacter sulfurreducens is used to synthesize magnetic iron oxide nanoparticles. A combination of electron microscopy, soft X-ray spectroscopy, and magnetometry techniques was employed to show that this method of biosynthesis results in high yields of crystalline nanoparticles with a narrow size distribution and magnetic properties equal to the best chemically synthesized materials. In particular, it is demonstrated here that cobalt ferrite (CoFe 2 O 4 ) nanoparticles with low temperature coercivity approaching 8 kOe and an effective anisotropy constant of ∼ 10 6 erg cm -3 can be manufactured through this biotechnological route. The dramatic enhancement in the magnetic properties of the nanoparticles by the introduction of high quantities of Co into the spinel structure represents a significant advance over previous biomineralization studies in this area using magnetotactic bacteria. The successful production of nanoparticulate ferrites achieved in this study at high yields could open up the way for the scaled-up industrial manufacture of nanoparticles using environmentally benign methodologies. Production of ferromagnetic nanoparticles for pioneering cancer therapy, drug delivery, chemical sensors, catalytic activity, photoconductive materials, as well as more traditional uses in data storage embodies a large area of inorganic synthesis research. In particular, the addition of transition metals other than Fe into the structure

  7. UV-screening, transparency and water barrier properties of semi refined iota carrageenan packaging film incorporated with ZnO nanoparticles

    Science.gov (United States)

    Khoirunnisa, Assifa Rahma; Joni, I. Made; Panatarani, Camellia; Rochima, Emma; Praseptiangga, Danar

    2018-02-01

    This study aims to develop film for food packaging application with high UV-screening, transparency and water barrier properties. Semi refined iota carrageenan (SRiC) nanocomposite films prepared by addition of zinc oxide (ZnO) nanoparticles as nanofiller using solution casting method. The effect of nanofiller with different concentration (0%, 0.5%, 1.0%, 1.5% w/w carrageenan) on UV-screening, transparency and water barrier properties of films were tested. The water barrier properties of the films were studied by measuring water vapor permeability (WVP) and the optical properties of the films were studied by using UV-Vis spectrophotometer at 280 nm for UV-screening test and at 660 nm for transparency test. WVP value of carrageenan films with addition of ZnO is low compared to a control carrageenan film and the lowest WVP value was found for the film with addition of 1.5% of ZnO. These result indicate that the addition of ZnO had a positive effect on the water barrier properties of the carrageenan matrix. Increase in the concentration of nanofiller leads to an increase in the UV-screening properties. Among all the films, carrageenan film with 1.5% ZnO has the highest UV-screening. The result showed that adding 0.5% and 1.0% of ZnO was insignificantly affect transparency of the films, however the transparency decreased sligthly when 1.5% ZnO was added. In conclusion, incorporating no more than 1.0% of ZnO to the films can obtain films with high UV-screening, transparency and water barrier properties and suitable for food packaging application.

  8. Dietary Bacillus subtilis-based direct-fed microbials alleviate LPS-induced intestinal immunological stress and improve intestinal barrier gene expression in commercial broiler chickens

    Science.gov (United States)

    The present study investigated the effects of B. subtilis-based probiotics on performance, modulation of host inflammatory responses and intestinal barrier integrity of broilers subjected to LPS challenge. Birds at day 0 of age were randomly allocated to one of the 3 dietary treatments - controls, ...

  9. Mango kernel starch-gum composite films: Physical, mechanical and barrier properties.

    Science.gov (United States)

    Nawab, Anjum; Alam, Feroz; Haq, Muhammad Abdul; Lutfi, Zubala; Hasnain, Abid

    2017-05-01

    Composite films were developed by the casting method using mango kernel starch (MKS) and guar and xanthan gums. The concentration of both gums ranged from 0% to 30% (w/w of starch; db). Mechanical properties, oxygen permeability (OP), water vapor permeability (WVP), solubility in water and color parameters of composite films were evaluated. The crystallinity and homogeneity between the starch and gums were also evaluated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The scanning electron micrographs showed homogeneous matrix, with no signs of phase separation between the components. XRD analysis demonstrated diminished crystalline peak. Regardless of gum type the tensile strength (TS) of composite films increased with increasing gum concentration while reverse trend was noted for elongation at break (EAB) which found to be decreased with increasing gum concentration. The addition of both guar and xanthan gums increased solubility and WVP of the composite films. However, the OP was found to be lower than that of the control with both gums. Furthermore, addition of both gums led to changes in transparency and opacity of MKS films. Films containing 10% (w/w) xanthan gum showed lower values for solubility, WVP and OP, while film containing 20% guar gum showed good mechanical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Fire and Gas Barrier Properties of Poly(styrene-co-acrylonitrile Nanocomposites Using Polycaprolactone/Clay Nanohybrid Based-Masterbatch

    Directory of Open Access Journals (Sweden)

    S. Benali

    2008-01-01

    Full Text Available Exfoliated nanocomposites are prepared by dispersion of poly(ε-caprolactone (PCL grafted montmorillonite nanohybrids used as masterbatches in poly(styrene-co-acrylonitrile (SAN. The PCL-grafted clay nanohybrids with high inorganic content are synthesized by in situ intercalative ring-opening polymerization of ε-caprolactone between silicate layers organomodified by alkylammonium cations bearing two hydroxyl functions. The polymerization is initiated by tin alcoholate species derived from the exchange reaction of tin(II bis(2-ethylhexanoate with the hydroxyl groups borne by the ammonium cations that organomodified the clay. These highly filled PCL nanocomposites (25 wt% in inorganics are dispersed as masterbatches in commercial poly(styrene-co-acrylonitrile by melt blending. SAN-based nanocomposites containing 3 wt% of inorganics are accordingly prepared. The direct blend of SAN/organomodified clay is also prepared for sake of comparison. The clay dispersion is characterized by wide-angle X-ray diffraction (WAXD, atomic force microscopy (AFM, and solid state NMR spectroscopy measurements. The thermal properties are studied by thermogravimetric analysis. The flame retardancy and gas barrier resistance properties of nanocomposites are discussed both as a function of the clay dispersion and of the matrix/clay interaction.

  11. Characterization and Properties of Electroless Nickel Plated Poly (ethylene terephthalate) Nonwoven Fabric Enhanced by Dielectric Barrier Discharge Plasma Pretreatment

    International Nuclear Information System (INIS)

    Geng Yamin; Lu Canhui; Liang Mei; Zhang Wei

    2010-01-01

    In order to develop a more economical pretreatment method for electroless nickel plating, a dielectric barrier discharge (DBD) plasma at atmospheric pressure was used to improve the hydrophilicity and adhesion of poly (ethylene terephthalate) (PET) nonwoven fabric. The properties of the PET nonwoven fabric including its liquid absorptive capacity (W A ), aging behavior, surface chemical composition, morphology of the surface, adhesion strength, surface electrical resistivity and electromagnetic interference (EMI)- shielding effectiveness (SE) were studied. The liquid absorptive capacity (W A ) increased due to the incorporation of oxygen-containing and nitrogen-containing functional groups on the surface of PET nonwoven fabric after DBD air-plasma treatment. The surface morphology of the nonwoven fibers became rougher after plasma treatment. Therefore, the surface was more prone to absorb tin sensitizer and palladium catalyst to form an active layer for the deposition of electroless nickel. SEM and X-ray diffraction (XRD) measurements indicated that a uniform coating of nickel was formed on the PET nonwoven fabric. The average EMI-SE of Ni-plating of PET nonwoven fabric maintained a relatively stable value (38.2 dB to 37.3 dB) in a frequency range of 50 MHz to 1500 MHz. It is concluded that DBD is feasible for pretreatment of nonwoven fabric for electroless nickel plating to prepare functional material with good EMI-SE properties.

  12. Delayed astrocytic contact with cerebral blood vessels in FGF-2 deficient mice does not compromise permeability properties at the developing blood-brain barrier.

    Science.gov (United States)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Unsicker, Klaus; Ek, C Joakim

    2016-11-01

    The brain functions within a specialized environment tightly controlled by brain barrier mechanisms. Understanding the regulation of barrier formation is important for understanding brain development and may also lead to finding new ways to deliver pharmacotherapies to the brain; access of many potentially promising drugs is severely hindered by these barrier mechanisms. The cellular composition of the neurovascular unit of the blood-brain barrier proper and their effects on regulation of its function are beginning to be understood. One hallmark of the neurovascular unit in the adult is the astroglial foot processes that tightly surround cerebral blood vessels. However their role in barrier formation is still unclear. In this study we examined barrier function in newborn, juvenile and adult mice lacking fibroblast growth factor-2 (FGF-2), which has been shown to result in altered astroglial differentiation during development. We show that during development of FGF-2 deficient mice the astroglial contacts with cerebral blood vessels are delayed compared with wild-type animals. However, this delay did not result in changes to the permeability properties of the blood brain barrier as assessed by exclusion of either small or larger sized molecules at this interface. In addition cerebral vessels were positive for tight-junction proteins and we observed no difference in the ultrastructure of the tight-junctions. The results indicate that the direct contact of astroglia processes to cerebral blood vessels is not necessary for either the formation of the tight-junctions or for basic permeability properties and function of the blood-brain barrier. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1201-1212, 2016. © 2016 Wiley Periodicals, Inc.

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

    Czech Academy of Sciences Publication Activity Database

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

    2011-01-01

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

  14. Microbial production of 1-octanol: A naturally excreted biofuel with diesel-like properties

    Directory of Open Access Journals (Sweden)

    M. Kalim Akhtar

    2015-12-01

    Full Text Available The development of sustainable, bio-based technologies to convert solar energy and carbon dioxide into fuels is a grand challenge. A core part of this challenge is to produce a fuel that is compatible with the existing transportation infrastructure. This task is further compounded by the commercial desire to separate the fuel from the biotechnological host. Based on its fuel characteristics, 1-octanol was identified as an attractive metabolic target with diesel-like properties. We therefore engineered a synthetic pathway specifically for the biosynthesis of 1-octanol in Escherichia coli BL21(DE3 by over-expression of three enzymes (thioesterase, carboxylic acid reductase and aldehyde reductase and one maturation factor (phosphopantetheinyl transferase. Induction of this pathway in a shake flask resulted in 4.4 mg 1-octanol L−1 h−1 which exceeded the productivity of previously engineered strains. Furthermore, the majority (73% of the fatty alcohol was localised within the media without the addition of detergent or solvent overlay. The deletion of acrA reduced the production and excretion of 1-octanol by 3-fold relative to the wild-type, suggesting that the AcrAB–TolC complex may be responsible for the majority of product efflux. This study presents 1-octanol as a potential fuel target that can be synthesised and naturally accumulated within the media using engineered microbes. Keywords: 1-Octanol, Fatty alcohol, Diesel, Biofuel, Excretion

  15. Anti-corrosive and anti-microbial properties of nanocrystalline Ni-Ag coatings

    Energy Technology Data Exchange (ETDEWEB)

    Raghupathy, Y.; Natarajan, K.A.; Srivastava, Chandan, E-mail: csrivastava@materials.iisc.ernet.in

    2016-04-15

    Graphical abstract: - Highlights: • Electrodeposition yielded phase-segregated, nanocrystalline Ni-Ag coatings. • Ni-Ag alloys exhibited smaller Ni crystals compared to pure Ni. • Ultra fine Ni grains of size 12–14 nm favoured Ni-Ag solid solution. • Nanocrystalline Ag resisted bio-fouling by Sulphate Reducing bacteria. • Ni-Ag outperformed pure Ni in corrosion and bio-corrosion tests. - Abstract: Anti-corrosive and anti-bacterial properties of electrodeposited nanocrystalline Ni-Ag coatings are illustrated. Pure Ni, Ni-7 at.% Ag, & Ni-14 at.% Ag coatings were electrodeposited on Cu substrate. Coating consisted of Ni-rich and Ag-rich solid solution phases. With increase in the Ag content, the corrosion resistance of the Ni-Ag coating initially increased and then decreased. The initial increase was due to the Ni-Ag solid solution. The subsequent decrease was due to the increased galvanic coupling between the Ag-rich and Ni-rich phases. For all Ag contents, the corrosion resistance of the Ni-Ag coating was higher than the pure Ni coating. Exposure to Sulphate Reducing Bacteria (SRB) revealed that the extent of bio-fouling decreased with increase in the Ag content. After 2 month exposure to SRB, the Ni-Ag coatings demonstrated less loss in corrosion resistance (58% for Ni-7 at.% Ag and 20% for Ni-14 at.% Ag) when compared pure Ni coating (115%).

  16. Antimicrobial and Barrier Properties of Bovine Gelatin Films Reinforced by Nano TiO2

    Directory of Open Access Journals (Sweden)

    R. Nassiri

    2013-11-01

    Full Text Available The effects of nano titanium dioxide incorporation were investigated on the water vaporpermeability, oxygen permeability, and antimicrobial properties of bovine gelatin films. The nano TiO2 (TiO2-N was homogenized by sonication and incorporated into bovine gelatin solutions at different concentrations(e.g. 1, 2, 3, and 5% w/w of dried gelatin. The permeability of the films to water vapor and oxygen wassignificantly decreased by incorporating of low concentration TiO2-N to gelatin solutions. TiO2-N gelatin filmsshowed an excellent antimicrobial activity against Staphylococcus aureus and Escherichia coli. Theseproperties suggest that TiO2-N has the potential as filler in gelatin-based films for using as an active packagingmaterials in pharmaceutical and food packaging industries.

  17. Structure-property relationships in flavour-barrier membranes with reduced high-temperature diffusivity

    International Nuclear Information System (INIS)

    Heitfeld, Kevin A.; Schaefer, Dale W.

    2009-01-01

    Encapsulation is used to decrease the premature release of volatile flavour ingredients while offering protection against environmental damage such as oxidation, light-induced reactions, etc. Hydroxypropyl cellulose (HPC) is investigated here as a 'smart,' temperature responsive membrane for flavour encapsulation and delivery. Gel films were synthesized and characterized by diffusion and small-angle neutron and X-ray scattering techniques. Increasing temperature typically increases the diffusion rate across a membrane; HPC, however, can be tailored to give substantially improved elevated temperature properties. Scattering results indicate processing conditions have a significant impact on membrane morphology (micro phase separation). Under certain synthetic conditions, micro phase separation is mitigated and the membranes show temperature-independent diffusivity between 25 C and 60 C.

  18. Schottky barrier parameters and structural properties of rapidly annealed Zr Schottky electrode on p-type GaN

    Science.gov (United States)

    Rajagopal Reddy, V.; Asha, B.; Choi, Chel-Jong

    2017-06-01

    The Schottky barrier junction parameters and structural properties of Zr/p-GaN Schottky diode are explored at various annealing temperatures. Experimental analysis showed that the barrier height (BH) of the Zr/p-GaN Schottky diode increases with annealing at 400 °C (0.92 eV (I-V)/1.09 eV (C-V)) compared to the as-deposited one (0.83 eV (I-V)/0.93 eV (C-V)). However, the BH decreases after annealing at 500 °C. Also, at different annealing temperatures, the series resistance and BH are assessed by Cheung's functions and their values compared. Further, the interface state density (N SS) of the diode decreases after annealing at 400 °C and then somewhat rises upon annealing at 500 °C. Analysis reveals that the maximum BH is obtained at 400 °C, and thus the optimum annealing temperature is 400 °C for the diode. The XPS and XRD analysis revealed that the increase in BH may be attributed to the creation of Zr-N phases with increasing annealing up to 400 °C. The BH reduces for the diode annealed at 500 °C, which may be due to the formation of Ga-Zr phases at the junction. The AFM measurements reveal that the overall surface roughness of the Zr film is quite smooth during rapid annealing process. Project supported by the R&D Program for Industrial Core Technology (No. 10045216) and the Transfer Machine Specialized Lighting Core Technology Development Professional Manpower Training Project (No. N0001363) Funded by the Ministry of Trade, Industry and Energy (MOTIE), Republic of Korea.

  19. Barriers to fusion

    International Nuclear Information System (INIS)

    Berriman, A.C.; Butt, R.D.; Dasgupta, M.; Hinde, D.J.; Morton, C.R.; Newton, J.O.

    1999-01-01

    The fusion barrier is formed by the combination of the repulsive Coulomb and attractive nuclear forces. Recent research at the Australian National University has shown that when heavy nuclei collide, instead of a single fusion barrier, there is a set of fusion barriers. These arise due to intrinsic properties of the interacting nuclei such deformation, rotations and vibrations. Thus the range of barrier energies depends on the properties of both nuclei. The transfer of matter between nuclei, forming a neck, can also affect the fusion process. High precision data have been used to determine fusion barrier distributions for many nuclear reactions, leading to new insights into the fusion process

  20. Effect of gamma ray on microbial load and chemical properties of Tahineh

    International Nuclear Information System (INIS)

    Al-Bachir, M.; Atoui, A.

    2015-04-01

    Tahineh is a Lebanese and Syrian food product elaborated from the milling of dehulled, roasted sesame seeds. It is used in a wide number of food preparations. Poor quality of raw material, poor manufacturing practices, lack of sophisticated quality control systems and lack of qualified employees are major elements that contribute to the production of inferior quality end product of Tahineh.The greatest problem is the presence of the pathogen Salmonella in this product. The appearance of Salmonella in Tahineh and the repetitive notification of Lebanese Tahineh on the international alerts represent a serious threat to the Lebanese population as well as to the Traditional Tahineh sector. In this study the effect of gamma irradiation on Salmonella and the overall chemical and sensory characteristics of Tahineh products produced in Lebanon have been investigated. Samples were artificially contaminated by Salmonella enterica arizonae at a level f 4.6 x 105 CFU/g. Polyethylene packed contaminated and non contaminated Tahineh samples were treated with 0, 1, 2 and 3 kGy of gamma rays using a 60Co source with a dose rate of 719 Gy/h (irradiation was conducted at the Syrian Atomic Energy Commission). Following the treatment, a dose of 3 kGy of gamma irradiation was shown to reduce the Salmonella population of Tahineh to level of 4.4 x 101 CFU/g. These results correspond to a 4 log10 decimal reduction. The applied irradiation doses did not cause any significant change in the physico-chemical properties of Tahineh.(author)

  1. Quantifying aquifer properties and freshwater resource in coastal barriers: a hydrogeophysical approach applied at Sasihithlu (Karnataka state, India)

    Science.gov (United States)

    Vouillamoz, J.-M.; Hoareau, J.; Grammare, M.; Caron, D.; Nandagiri, L.; Legchenko, A.

    2012-11-01

    Many human communities living in coastal areas in Africa and Asia rely on thin freshwater lenses for their domestic supply. Population growth together with change in rainfall patterns and sea level will probably impact these vulnerable groundwater resources. Spatial knowledge of the aquifer properties and creation of a groundwater model are required for achieving a sustainable management of the resource. This paper presents a ready-to-use methodology for estimating the key aquifer properties and the freshwater resource based on the joint use of two non-invasive geophysical tools together with common hydrological measurements. We applied the proposed methodology in an unconfined aquifer of a coastal sandy barrier in South-Western India. We jointly used magnetic resonance and transient electromagnetic soundings and we monitored rainfall, groundwater level and groundwater electrical conductivity. The combined interpretation of geophysical and hydrological results allowed estimating the aquifer properties and mapping the freshwater lens. Depending on the location and season, we estimate the freshwater reserve to range between 400 and 700 L m-2 of surface area (± 50%). We also estimate the recharge using time lapse geophysical measurements with hydrological monitoring. After a rainy event close to 100% of the rain is reaching the water table, but the net recharge at the end of the monsoon is less than 10% of the rain. Thus, we conclude that a change in rainfall patterns will probably not impact the groundwater resource since most of the rain water recharging the aquifer is flowing towards the sea and the river. However, a change in sea level will impact both the groundwater reserve and net recharge.

  2. Quantifying aquifer properties and freshwater resource in coastal barriers: a hydrogeophysical approach applied at Sasihithlu (Karnataka state, India

    Directory of Open Access Journals (Sweden)

    J.-M. Vouillamoz

    2012-11-01

    Full Text Available Many human communities living in coastal areas in Africa and Asia rely on thin freshwater lenses for their domestic supply. Population growth together with change in rainfall patterns and sea level will probably impact these vulnerable groundwater resources. Spatial knowledge of the aquifer properties and creation of a groundwater model are required for achieving a sustainable management of the resource. This paper presents a ready-to-use methodology for estimating the key aquifer properties and the freshwater resource based on the joint use of two non-invasive geophysical tools together with common hydrological measurements.

    We applied the proposed methodology in an unconfined aquifer of a coastal sandy barrier in South-Western India. We jointly used magnetic resonance and transient electromagnetic soundings and we monitored rainfall, groundwater level and groundwater electrical conductivity. The combined interpretation of geophysical and hydrological results allowed estimating the aquifer properties and mapping the freshwater lens. Depending on the location and season, we estimate the freshwater reserve to range between 400 and 700 L m−2 of surface area (± 50%. We also estimate the recharge using time lapse geophysical measurements with hydrological monitoring. After a rainy event close to 100% of the rain is reaching the water table, but the net recharge at the end of the monsoon is less than 10% of the rain. Thus, we conclude that a change in rainfall patterns will probably not impact the groundwater resource since most of the rain water recharging the aquifer is flowing towards the sea and the river. However, a change in sea level will impact both the groundwater reserve and net recharge.

  3. Mechanical and Barrier Properties of Semi Refined Kappa Carrageenan-based Composite Edible Film and Its Application on Minimally Processed Chicken Breast Fillet

    Science.gov (United States)

    Praseptiangga, D.; Maimuni, B. H.; Manuhara, G. J.; Muhammad, D. R. A.

    2018-03-01

    Kappa-carrageenan (KC) is one of the most interesting biopolymers that is composed of a linear chain of sulfated galactans and extracted from red seaweed, Kappaphycus alvarezii. It shows good potential for development as a source of biodegradable or edible films. However, KC films do not have good water vapor barrier properties, as they are intrinsically hydrophilic. Palmitic acid (PA) as hydrophobic material was incorporated into semi-refined kappa-carrageenan (SRKC) edible films in order to improve water vapor barrier properties. In this study, composite films based on SRKC incorporating PA were prepared and their applications on minimally processed chicken breast fillet were evaluated. Composite SRKC-based films with varying concentrations of PA (5%, 10%, and 15% w/w) were obtained by a solvent casting method. Their mechanical and barrier properties were investigated. Results showed that the incorporation of PA in films caused an increase in thickness, but decrease in water vapor transmission rate (WVTR) as the concentration of PA increased (from 5% to 15% w/w). Composite SRKC-based edible film incorporating 15% w/w of PA presented better water vapor barrier properties as compared to other films with 5% and 10% w/w PA incorporation. Thus, formulation containing 15% w/w PA was used as a wrapping material for film application on minimally processed chicken breast fillet. The application results showed that the incorporation of PA in film caused an effect (p 0.05) change the color of minimally processed chicken breast fillet.

  4. Gas sorption and barrier properties of polymeric membranes from molecular dynamics and Monte Carlo simulations.

    Science.gov (United States)

    Cozmuta, Ioana; Blanco, Mario; Goddard, William A

    2007-03-29

    It is important for many industrial processes to design new materials with improved selective permeability properties. Besides diffusion, the molecule's solubility contributes largely to the overall permeation process. This study presents a method to calculate solubility coefficients of gases such as O2, H2O (vapor), N2, and CO2 in polymeric matrices from simulation methods (Molecular Dynamics and Monte Carlo) using first principle predictions. The generation and equilibration (annealing) of five polymer models (polypropylene, polyvinyl alcohol, polyvinyl dichloride, polyvinyl chloride-trifluoroethylene, and polyethylene terephtalate) are extensively described. For each polymer, the average density and Hansen solubilities over a set of ten samples compare well with experimental data. For polyethylene terephtalate, the average properties between a small (n = 10) and a large (n = 100) set are compared. Boltzmann averages and probability density distributions of binding and strain energies indicate that the smaller set is biased in sampling configurations with higher energies. However, the sample with the lowest cohesive energy density from the smaller set is representative of the average of the larger set. Density-wise, low molecular weight polymers tend to have on average lower densities. Infinite molecular weight samples do however provide a very good representation of the experimental density. Solubility constants calculated with two ensembles (grand canonical and Henry's constant) are equivalent within 20%. For each polymer sample, the solubility constant is then calculated using the faster (10x) Henry's constant ensemble (HCE) from 150 ps of NPT dynamics of the polymer matrix. The influence of various factors (bad contact fraction, number of iterations) on the accuracy of Henry's constant is discussed. To validate the calculations against experimental results, the solubilities of nitrogen and carbon dioxide in polypropylene are examined over a range of

  5. Influence of material properties on gloves' bacterial barrier efficacy in the presence of microperforation.

    Science.gov (United States)

    Bardorf, Michael Hermann; Jäger, Bernd; Boeckmans, Eric; Kramer, Axel; Assadian, Ojan

    2016-12-01

    Medical examination gloves and surgical gloves protect the wearer directly and the patient indirectly from the risk of contamination. Because of concerns related to latex allergy, an increasing trend toward the use of synthetic gloves made of materials other than latex is observable. However, currently it is unknown if the physical properties of different materials may influence bacterial passage in case of a glove puncture. We examined 9 different medical examination gloves from various manufacturers made of nitrile (n = 4), latex (n = 3), or neoprene (n = 2). Additionally, 1 latex surgical glove each with and without antibacterial chlorhexidine gluconate coating and 1 synthetic surgical glove made of thermoplastic elastomer were included in the experiments. The studied materials were perforated following a standardized procedure, and direct bacterial passage was measured under dynamic conditions. Glove elasticity at 1 cm up to 2.5 cm elongation was measured following EN 455-2. Nitrile gloves demonstrated higher material stiffness compared with latex gloves. Medical examination gloves made of nitrile and neoprene showed a 10-fold higher bacterial passage through a standardized puncture compared with latex gloves. All surgical gloves showed a lower bacterial passage compared with the tested examination gloves. Bacterial passage through punctures is correlated with the stiffness or elasticity of the glove material. Therefore, gloves made of latex may have an increased protective effect in case of a glove breach. Whenever gloves are purchased and selected, a risk-benefit assessment should be conducted, balancing the risk of allergy against the degree of required protection in case of a glove puncture. Copyright © 2016 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

  6. Phenotypic properties and microbial diversity of methanogenic granules from a full-scale UASB reactor treating brewery wastewater

    NARCIS (Netherlands)

    Diaz, E.E.; Stams, A.J.M.; Amils, R.; Sanz, J.L.

    2006-01-01

    Methanogenic granules from an anaerobic bioreactor that treated wastewater of a beer brewery consisted of different morphological types of granules. In this study, the microbial compositions of the different granules were analyzed by molecular microbiological techniques: cloning, denaturing gradient

  7. Antibacterial and barrier properties of oriented polymer films with ZnO thin films applied with atomic layer deposition at low temperatures

    International Nuclear Information System (INIS)

    Vähä-Nissi, Mika; Pitkänen, Marja; Salo, Erkki; Kenttä, Eija; Tanskanen, Anne; Sajavaara, Timo; Putkonen, Matti; Sievänen, Jenni; Sneck, Asko; Rättö, Marjaana; Karppinen, Maarit; Harlin, Ali

    2014-01-01

    Concerns on food safety, and need for high quality and extended shelf-life of packaged foods have promoted the development of antibacterial barrier packaging materials. Few articles have been available dealing with the barrier or antimicrobial properties of zinc oxide thin films deposited at low temperature with atomic layer deposition (ALD) onto commercial polymer films typically used for packaging purposes. The purpose of this paper was to study the properties of ZnO thin films compared to those of aluminum oxide. It was also possible to deposit ZnO thin films onto oriented polylactic acid and polypropylene films at relatively low temperatures using ozone instead of water as an oxidizing precursor for diethylzinc. Replacing water with ozone changed both the structure and the chemical composition of films deposited on silicon wafers. ZnO films deposited with ozone contained large grains covered and separated probably by a more amorphous and uniform layer. These thin films were also assumed to contain zinc salts of carboxylic acids. The barrier properties of a 25 nm ZnO thin film deposited with ozone at 100 °C were quite close to those obtained earlier with ALD Al 2 O 3 of similar apparent thickness on similar polymer films. ZnO thin films deposited at low temperature indicated migration of antibacterial agent, while direct contact between ZnO and Al 2 O 3 thin films and bacteria promoted antibacterial activity. - Highlights: • Thin films were grown from diethylzinc also with ozone instead of water at 70 and 100 °C. • ZnO films deposited with diethylzinc and ozone had different structures and chemistries. • Best barrier properties obtained with zinc oxide films close to those obtained with Al 2 O 3 • Ozone as oxygen source provided better barrier properties at 100 °C than water. • Both aluminum and zinc oxide thin films showed antimicrobial activity against E. coli

  8. Mechanical and moisture barrier properties of titanium dioxide nanoparticles and halloysite nanotubes reinforced polylactic acid (PLA)

    International Nuclear Information System (INIS)

    Alberton, J; Martelli, S M; Soldi, V; Fakhouri, F M

    2014-01-01

    Polylactic acid (PLA) has been larger used in biomedical field due to its low toxicity and biodegradability. The aim of this study was to produce PLLA nanocomposites, by melt extrusion, containing Halloysite nanotubes (HNT) and/or titanium dioxide (TiO 2 ) nanoparticles. Immediately after drying, PLLA was mechanically homogenized with the nanofillers and then melt blended using a single screw extruder (L/D = 30) at a speed of 110 rpm, with three heating zones in which the following temperatures were maintained: 150, 150 and 160°C (AX Plasticos model AX14 LD30). The film samples were obtained by compression molding in a press with a temperature profile of 235 ± 5°C for 2.5 min, after pressing, films were cooled up to room temperature. The mechanical tests were performed according to ASTM D882-09 and the water vapor permeability (WVP) was measured according to ASTM E-96, in triplicate. The tensile properties indicated that the modulus was improved with increased TiO 2 content up to 1g/100g PLLA. The Young's modulus (YM) of the PLA was increased from 3047 MPa to 3222 MPa with the addition of 1g TiO 2 /100g PLLA. The tensile strength (TS) of films increases with the TiO 2 content. In both cases, the YM and TS are achieved at the 1% content of TiO 2 and is due to the reinforcing effect of nanoparticles. Pristine PLA showed a strain at break (SB) of 3.56%, while the SB of nanocomposites were significant lower, for instance the SB of composite containing 7.5 g HNT/100g PLLA was around 1.90 %. The WVP of samples was increased by increasing the nano filler content. It should be expected that an increase of nanofiller content would decrease the mass transfer of water molecules throughout the samples due to the increase in the way water molecules will have to cross to permeate the material. However, this was not observed. Therefore, this result can be explained considering the molecular structure of both fillers, which contain several hydroxyl groups in the surface

  9. Investigation of microstructure and properties of ultrathin graded ZrNx self-assembled diffusion barrier in deep nano-vias prepared by plasma ion immersion implantation

    Science.gov (United States)

    Zou, Jianxiong; Liu, Bo; Lin, Liwei; Lu, Yuanfu; Dong, Yuming; Jiao, Guohua; Ma, Fei; Li, Qiran

    2018-01-01

    Ultrathin graded ZrNx self-assembled diffusion barriers with controllable stoichiometry was prepared in Cu/p-SiOC:H interfaces by plasma immersion ion implantation (PIII) with dynamic regulation of implantation fluence. The fundamental relationship between the implantation fluence of N+ and the stoichiometry and thereby the electrical properties of the ZrNx barrier was established. The optimized fluence of a graded ZrN thin film with gradually decreased Zr valence was obtained with the best electrical performance as well. The Cu/p-SiOC:H integration is thermally stable up to 500 °C due to the synergistic effect of Cu3Ge and ZrNx layers. Accordingly, the PIII process was verified in a 100-nm-thick Cu dual-damascene interconnect, in which the ZrNx diffusion barrier of 1 nm thick was successfully self-assembled on the sidewall without barrier layer on the via bottom. In this case, the via resistance was reduced by approximately 50% in comparison with Ta/TaN barrier. Considering the results in this study, ultrathin ZrNx conformal diffusion barrier can be adopted in the sub-14 nm technology node.

  10. Ionization asymmetry effects on the properties modulation of atmospheric pressure dielectric barrier discharge sustained by tailored voltage waveforms

    Science.gov (United States)

    Zhang, Z. L.; Nie, Q. Y.; Zhang, X. N.; Wang, Z. B.; Kong, F. R.; Jiang, B. H.; Lim, J. W. M.

    2018-04-01

    The dielectric barrier discharge (DBD) is a promising technology to generate high density and uniform cold plasmas in atmospheric pressure gases. The effective independent tuning of key plasma parameters is quite important for both application-focused and fundamental studies. In this paper, based on a one-dimensional fluid model with semi-kinetics treatment, numerical studies of ionization asymmetry effects on the properties modulation of atmospheric DBD sustained by tailored voltage waveforms are reported. The driving voltage waveform is characterized by an asymmetric-slope fundamental sinusoidal radio frequency signal superimposing one or more harmonics, and the effects of the number of harmonics, phase shift, as well as the fluctuation of harmonics on the sheath dynamics, impact ionization of electrons and key plasma parameters are investigated. The results have shown that the electron density can exhibit a substantial increase due to the effective electron heating by a spatially asymmetric sheath structure. The strategic modulation of harmonics number and phase shift is capable of raising the electron density significantly (e.g., nearly three times in this case), but without a significant increase in the gas temperature. Moreover, by tailoring the fluctuation of harmonics with a steeper slope, a more profound efficiency in electron impact ionization can be achieved, and thus enhancing the electron density effectively. This method then enables a novel alternative approach to realize the independent control of the key plasma parameters under atmospheric pressure.

  11. Transparent bionanocomposite films based on chitosan and TEMPO-oxidized cellulose nanofibers with enhanced mechanical and barrier properties.

    Science.gov (United States)

    Soni, Bhawna; Hassan, El Barbary; Schilling, M Wes; Mahmoud, Barakat

    2016-10-20

    The development of biobased active films for use in food packaging is increasing due to low cost, environmental appeal, renewability and availability. The objective of this research was to develop an effective and complete green approach for the production of bionanocomposite films with enhanced mechanical and barrier properties. This was accomplished by incorporating TEMPO-oxidized cellulose nanofibers (2,2,6,6-tetramethylpiperidine-1-oxyl radical) into a chitosan matrix. An aqueous suspension of chitosan (100-75wt%), sorbitol (25wt%) and TEMPO-oxidized cellulose nanofibers (TEMPO-CNFs, 0-25wt%) were cast in an oven at 40°C for 2-4days. Films were preconditioned at 25°C and 50% RH for characterization. The surface morphology of the films was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties and crystal structure of the films were evaluated by thermogravimetric analysis (TGA-DTG) and X-ray diffraction (XRD). Incorporation of TEMPO-CNFs enhanced the mechanical strength of the films due to the high aspect ratio (3-20nm width, and 10-100nm length) of TEMPO-CNFs and strong interactions with the chitosan matrix. Oxygen and water vapor transmission rates for films that are prepared with chitosan and TEMPO-CNFs (15-25wt%) were significantly reduced. Furthermore, these bionanocomposite films had good thermal stability. Use of TEMPO-CNFs in this method makes it possible to produce bionanocomposite films that are flexible, transparent, and thus have potential in food packaging applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Influence of Food with High Moisture Content on Oxygen Barrier Property of Polyvinyl Alcohol (PVA)/Vermiculite Nanocomposite Coated Multilayer Packaging Film.

    Science.gov (United States)

    Kim, Jung Min; Lee, Min Hyeock; Ko, Jung A; Kang, Dong Ho; Bae, Hojae; Park, Hyun Jin

    2018-02-01

    This study investigates the potential complications in applying nanoclay-based waterborne coating to packaging films for food with high moisture content. Multilayer packaging films were prepared by dry laminating commercially available polyvinyl alcohol (PVA)/vermiculite nanocomposite coating films and linear low-density polyethylene film, and the changes in oxygen barrier properties were investigated according to different relative humidity using 3 types of food simulants. When the relative humidity was above 60%, the oxygen permeability increased sharply, but this was reversible. Deionized water and 3% acetic acid did not cause any large structural change in the PVA/vermiculite nanocomposite but caused a reversible deterioration of the oxygen barrier properties. In contrast, 50% ethanol, a simulant for the semifatty food, induced irreversible structural changes with deterioration of the oxygen barrier property. These changes are due to the characteristics of PVA rather than vermiculite. We believe this manuscript would be of interest to the wide group of researchers, organizations, and companies in the field of developing nanoclay-based gas barrier packaging for foods with high moisture content. Hence, we wish to diffuse our knowledge to the scientific community. © 2018 Institute of Food Technologists®.

  13. Coupled modelling (transport-reaction) of the fluid-clay interactions and their feed back on the physical properties of the bentonite engineered clay barrier system

    International Nuclear Information System (INIS)

    Marty, N.

    2006-11-01

    The originality of this work is to process feed back effects of mineralogical and chemical modifications of clays, in storage conditions, on their physical properties and therefore on their transport characteristics (porosity, molecular diffusion, permeability). These feed back effects are modelled using the KIRMAT code (Kinetic of Reaction and MAss Transfer) developed from the kinetic code KINDIS by adding the effect of water renewal in the mineral-solution reactive cells. KIRMAT resolves mass balance equations associated with mass transport together with the geochemical reactions in a 1D approach. After 100 000 years of simulated interaction at 100 C, with the fluid of the Callovo-Oxfordian geological level (COX) and with iron provided by the steel overpack corrosion, the montmorillonite of the clay barrier is only partially transformed (into illite, chlorite, saponite...). Only outer parts of the modelled profile seem to be significantly affected by smectite dissolution processes, mainly at the interface with the geological environment. The modifications of physical properties show a closure of the porosity at the boundaries of the barrier, by creating a decrease of mass transport by molecular diffusion, essentially at the interface with the iron. Permeability laws applied to this system show a decrease of the hydraulic conductivity correlated with the porosity evolution. Near the COX, the swelling pressure of the clays from the barrier decreases. In the major part of the modelled profile, the engineered clay barrier system seems to keep its initial physical properties (porosity, molecular diffusion, permeability, swelling pressure) and functionalities. (author)

  14. Silicon oxide barrier films deposited on PET foils in pulsed plasmas: influence of substrate bias on deposition process and film properties

    International Nuclear Information System (INIS)

    Steves, S; Bibinov, N; Awakowicz, P; Ozkaya, B; Liu, C-N; Ozcan, O; Grundmeier, G

    2013-01-01

    A widely used plastic for packaging, polyethylene terephtalate (PET) offers limited barrier properties against gas permeation. For many applications of PET (from food packaging to micro electronics) improved barrier properties are essential. A silicon oxide barrier coating of PET foils is applied by means of a pulsed microwave driven low-pressure plasma. While the adjustment of the microwave power allows for a control of the ion production during the plasma pulse, a substrate bias controls the energy of ions impinging on the substrate. Detailed analysis of deposited films applying oxygen permeation measurements, x-ray photoelectron spectroscopy and atomic force microscopy are correlated with results from plasma diagnostics describing the deposition process. The influence of a change in process parameters such as gas mixture and substrate bias on the gas temperature, electron density, mean electron energy, ion energy and the atomic oxygen density is studied. An additional substrate bias results in an increase in atomic oxygen density up to a factor of 6, although plasma parameter such as electron density of n e = 3.8 ± 0.8 × 10 17 m −3 and electron temperature of k B T e = 1.7 ± 0.1 eV are unmodified. It is shown that atomic oxygen densities measured during deposition process higher than n O = 1.8 × 10 21 m −3 yield in barrier films with a barrier improvement factor up to 150. Good barrier films are highly cross-linked and show a smooth morphology. (paper)

  15. Luminescence materials for pH and oxygen sensing in microbial cells - structures, optical properties, and biological applications.

    Science.gov (United States)

    Zou, Xianshao; Pan, Tingting; Chen, Lei; Tian, Yanqing; Zhang, Weiwen

    2017-09-01

    Luminescence including fluorescence and phosphorescence sensors have been demonstrated to be important for studying cell metabolism, and diagnosing diseases and cancer. Various design principles have been employed for the development of sensors in different formats, such as organic molecules, polymers, polymeric hydrogels, and nanoparticles. The integration of the sensing with fluorescence imaging provides valuable tools for biomedical research and applications at not only bulk-cell level but also at single-cell level. In this article, we critically reviewed recent progresses on pH, oxygen, and dual pH and oxygen sensors specifically for their application in microbial cells. In addition, we focused not only on sensor materials with different chemical structures, but also on design and applications of sensors for better understanding cellular metabolism of microbial cells. Finally, we also provided an outlook for future materials design and key challenges in reaching broad applications in microbial cells.

  16. Transcriptional profiling of human brain endothelial cells reveals key properties crucial for predictive in vitro blood-brain barrier models.

    Directory of Open Access Journals (Sweden)

    Eduard Urich

    Full Text Available Brain microvascular endothelial cells (BEC constitute the blood-brain barrier (BBB which forms a dynamic interface between the blood and the central nervous system (CNS. This highly specialized interface restricts paracellular diffusion of fluids and solutes including chemicals, toxins and drugs from entering the brain. In this study we compared the transcriptome profiles of the human immortalized brain endothelial cell line hCMEC/D3 and human primary BEC. We identified transcriptional differences in immune response genes which are directly related to the immortalization procedure of the hCMEC/D3 cells. Interestingly, astrocytic co-culturing reduced cell adhesion and migration molecules in both BECs, which possibly could be related to regulation of immune surveillance of the CNS controlled by astrocytic cells within the neurovascular unit. By matching the transcriptome data from these two cell lines with published transcriptional data from freshly isolated mouse BECs, we discovered striking differences that could explain some of the limitations of using cultured BECs to study BBB properties. Key protein classes such as tight junction proteins, transporters and cell surface receptors show differing expression profiles. For example, the claudin-5, occludin and JAM2 expression is dramatically reduced in the two human BEC lines, which likely explains their low transcellular electric resistance and paracellular leakiness. In addition, the human BEC lines express low levels of unique brain endothelial transporters such as Glut1 and Pgp. Cell surface receptors such as LRP1, RAGE and the insulin receptor that are involved in receptor-mediated transport are also expressed at very low levels. Taken together, these data illustrate that BECs lose their unique protein expression pattern outside of their native environment and display a more generic endothelial cell phenotype. A collection of key genes that seems to be highly regulated by the local

  17. Antibacterial and Barrier Properties of Gelatin Coated by Electrospun Polycaprolactone Ultrathin Fibers Containing Black Pepper Oleoresin of Interest in Active Food Biopackaging Applications

    Directory of Open Access Journals (Sweden)

    Kelly Johana Figueroa-Lopez

    2018-03-01

    Full Text Available The present study evaluated the effect of using electrospun polycaprolactone (PCL as a barrier coating and black pepper oleoresin (OR as a natural extract on the morphology, thermal, mechanical, antimicrobial, oxygen, and water vapor barrier properties of solvent cast gelatin (GEL. The antimicrobial activity of the developed multilayer system obtained by the so-called electrospinning coating technique was also evaluated against Staphylococcus aureus strains for 10 days. The results showed that the multilayer system containing PCL and OR increased the thermal resistance, elongated the GEL film, and significantly diminished its permeance to water vapor. Active multilayer systems stored in hermetically closed bottles increased their antimicrobial activity after 10 days by inhibiting the growth of Staphylococcus aureus. This study demonstrates that addition of electrospun PCL ultrathin fibers and OR improved the properties of GEL films, which promoted its potential use in active food packaging applications.

  18. Microbial properties and litter and soil nutrients after two prescribed fires in developing savannas in an upland Missouri Ozark Forest

    Science.gov (United States)

    Felix, Jr. Ponder; Mahasin Tadros; Edward F. Loewenstein

    2009-01-01

    On some landscapes periodic fire may be necessary to develop and maintain oak-dominated savannas. We studied the effects of two annual prescribed burns to determine their effect on microbial activity and soil and litter nutrients 1 year after the last burn. Surface litter and soil from the upper 0?5 cm soil layer in three developing savannas (oak-hickory, ...

  19. Microscopic Examination of Distribution and Phenotypic Properties of Phylogenetically Diverse Chloroflexaceae-Related Bacteria in Hot Spring Microbial Mats

    DEFF Research Database (Denmark)

    Nübel, U.; Bateson, Mary M.; Vandieken, V.

    2002-01-01

    We investigated the diversity, distribution, and phenotypes of uncultivated Chloroflexaceae-related bacteria in photosynthetic microbial mats of an alkaline hot spring (Mushroom Spring, Yellowstone National Park). By applying a directed PCR approach, molecular cloning, and sequence analysis of 16S...

  20. Impacts of forest harvest on active carbon and microbial properties of a volcanic ash cap soil in northern Idaho

    Science.gov (United States)

    Deborah S. Page-Dumroese; Matt D. Busse; Steven T. Overby; Brian D. Gardner; Joanne M. Tirocke

    2015-01-01

    Soil quality assessments are essential for determining impacts on belowground microbial community structure and function. We evaluated the suitability of active carbon (C), a rapid field test, as an indicator of soil biological quality in five paired forest stands (clear cut harvested 40 years prior and unharvested) growing on volcanic ash-cap soils in northern Idaho....

  1. Formulation and characterization of polyethylenes and organo-clays. Barrier properties of the obtained nano-composites; Formulation et caracterisation de polyethylenes charges avec des argiles. Proprietes barriere des nanocomposites obtenus

    Energy Technology Data Exchange (ETDEWEB)

    Wache, R

    2004-10-01

    The particularity of polymer layered silicate nano-composites is based on the exfoliation of the clay platelets in the polymer matrix. Therefore properties may be dramatically modified with very low clay loading. In this work polyethylene and organo-clay have been melt blended. Due to a lack of polarity, the polymer chains do not intercalate the clay stacking. However exfoliation is achieved using maleate polyethylene. We used this polymer as a compatibilizer to promote clay exfoliation in the polyethylene matrix. Partial exfoliation is obtained. Barrier properties of these materials have been characterized. Permeability is higher for the clay reinforced products than their matrix. To understand the poor permeability results a tortuosity model has been developed. The quality of the interface seems to be involved. Several organo-clays and compatibilizers have been tested to improve it. But for the concentrations of these products used polyethylene clay interactions always exist and lead to an increase of diffusion. (author)

  2. Antibacterial and barrier properties of oriented polymer films with ZnO thin films applied with atomic layer deposition at low temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Vähä-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Pitkänen, Marja; Salo, Erkki; Kenttä, Eija [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Tanskanen, Anne, E-mail: Anne.Tanskanen@aalto.fi [Aalto University, School of Chemical Technology, Department of Chemistry, Laboratory of Inorganic Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Sajavaara, Timo, E-mail: timo.sajavaara@jyu.fi [University of Jyväskylä, Department of Physics, P.O. Box 35, FI-40014 Jyväskylä (Finland); Putkonen, Matti; Sievänen, Jenni; Sneck, Asko; Rättö, Marjaana [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland); Karppinen, Maarit, E-mail: Maarit.Karppinen@aalto.fi [Aalto University, School of Chemical Technology, Department of Chemistry, Laboratory of Inorganic Chemistry, P.O. Box 16100, FI-00076 Aalto (Finland); Harlin, Ali [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044, VTT (Finland)

    2014-07-01

    Concerns on food safety, and need for high quality and extended shelf-life of packaged foods have promoted the development of antibacterial barrier packaging materials. Few articles have been available dealing with the barrier or antimicrobial properties of zinc oxide thin films deposited at low temperature with atomic layer deposition (ALD) onto commercial polymer films typically used for packaging purposes. The purpose of this paper was to study the properties of ZnO thin films compared to those of aluminum oxide. It was also possible to deposit ZnO thin films onto oriented polylactic acid and polypropylene films at relatively low temperatures using ozone instead of water as an oxidizing precursor for diethylzinc. Replacing water with ozone changed both the structure and the chemical composition of films deposited on silicon wafers. ZnO films deposited with ozone contained large grains covered and separated probably by a more amorphous and uniform layer. These thin films were also assumed to contain zinc salts of carboxylic acids. The barrier properties of a 25 nm ZnO thin film deposited with ozone at 100 °C were quite close to those obtained earlier with ALD Al{sub 2}O{sub 3} of similar apparent thickness on similar polymer films. ZnO thin films deposited at low temperature indicated migration of antibacterial agent, while direct contact between ZnO and Al{sub 2}O{sub 3} thin films and bacteria promoted antibacterial activity. - Highlights: • Thin films were grown from diethylzinc also with ozone instead of water at 70 and 100 °C. • ZnO films deposited with diethylzinc and ozone had different structures and chemistries. • Best barrier properties obtained with zinc oxide films close to those obtained with Al{sub 2}O{sub 3} • Ozone as oxygen source provided better barrier properties at 100 °C than water. • Both aluminum and zinc oxide thin films showed antimicrobial activity against E. coli.

  3. Microstructure, electrical, and optical properties of evaporated PtSi/p-Si(100) Schottky barriers as high quantum efficient infrared detectors

    International Nuclear Information System (INIS)

    Wu Jihhuah; Chang Rongsen; Horng Gwoji

    2004-01-01

    The effects of the microstructure and the electrical and optical properties on the formation at highly efficient infrared PtSi Schottky barrier detectors (SBD) have been studied in detail. Two- to twelve-nanometer-thick PtSi films were grown by evaporation at temperature ranging from 350 to 550 deg. C. The electron diffraction patterns indicate the existence of both the (11-bar0) and (12-bar1) orientations when PtSi films formed at 350 deg. C. However, the diffraction patterns show only the (12-bar1) orientation when the PtSi films are formed at 450 deg. C or above. The electrical barrier height of the Schottky barrier detector that formed at 350 deg. C was about 20 meV higher than that formed at 450 deg. C or above. The grain size and the film thickness had a negligible effect on the electrical barrier height. However, the optical performance was strongly dependent on the film thickness and the growth conditions. The 350 deg. C PtSi film showed increased quantum efficiency as the film thickness decreased. The optimal thickness that provided the highest responsivity was 2 nm. On the other hand, the optimal thickness shifted to 8 nm for PtSi film formed at 450 deg. C or above. These results indicate that the quantum efficiency of a detector can be improved if the PtSi film has an orientation at (12-bar1), a larger grain size, and an optimal film thickness

  4. Transport properties of Josephson contacts with ferromagnetic tunnel barriers; Transporteigenschaften von Josephson-Kontakten mit ferromagnetischer Tunnelbarriere

    Energy Technology Data Exchange (ETDEWEB)

    Sprungmann, Dirk

    2010-01-28

    The combination of the Josephson and the proximity effect is possible by the introduction of a ferromagnetic barrier into a Josephson contact resulting in a so called π coupling. The supra current through these contacts is flowing in the reverse direction. Specific new electronic circuits such as phase shifting devices are possible, for instance for high-speed analog-digital transducers. In the frame of this thesis SIFS Josephson contacts were studied, with a barrier consisting of a thin insulating Al2Ox barrier layer and a ferromagnetic thin film. For the ferromagnetic material weak ferromagnetic Ni(0.6)Cu(0.4), the strong ferromagnetic Fe(0.25)Co(0.75) and the ternary Heusler alloys Co2MnSn and Cu2MnAl were used. Josephson contacts with π coupling were realized with the NiCu alloy, triplet superconductivity seems to appear with the Heusler systems.

  5. Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua [College of Chemistry and Material Science, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China); Wang, Qingguo, E-mail: wqgyyy@126.com [College of Food Science and Engineering, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China); Xu, Jing, E-mail: jiaxu@sdau.edu.cn [College of Chemistry and Material Science, Shandong Agricultural University, 61 Daizong Street, Tai' an 271018 (China)

    2016-11-15

    Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180–914 cm{sup −1}) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention. - Graphical abstract: The fabrication process of LLDPE/LDH composite films. - Highlights: • LDH with basal spacing of 4.07 nm was synthesized by high-energy ball milling. • LLDPE composite films with homogeneous LDH dispersion were fabricated. • The properties of LLDPE/LDH composite films were improved. • LLDPE/LDH composite films show superior heat retention property.

  6. Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

    International Nuclear Information System (INIS)

    Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua; Wang, Qingguo; Xu, Jing

    2016-01-01

    Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180–914 cm −1 ) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention. - Graphical abstract: The fabrication process of LLDPE/LDH composite films. - Highlights: • LDH with basal spacing of 4.07 nm was synthesized by high-energy ball milling. • LLDPE composite films with homogeneous LDH dispersion were fabricated. • The properties of LLDPE/LDH composite films were improved. • LLDPE/LDH composite films show superior heat retention property.

  7. Study of the Properties of Bentonites for their use in Clay Geo synthetic Barriers; Estudio de la propiedades de las bentonitas para su utilizacion en barreras geosinteticas arcillosas

    Energy Technology Data Exchange (ETDEWEB)

    Leiro Lopez, A.; Mateo Sanz, B.; Garcia Cidoncha, H.; Blanco Fernandez, M.

    2014-02-01

    Bentonites used for the production of clay geo synthetic barriers need to meet some properties so that they can be a waterproofing system. among the bentonites used in industry, sodium bentonite has the lowest permeability due to its high water absorption capacity in the inter-laminar space, causing it to swell and form a barrier to water flow. this paper provides the study of the properties of four bentonite to evaluate their quality the study of the properties of four bentonite to evaluate their quality. For this study, the main properties have been tested: water absorption, swelling index, fluid loss, cation exchange capacity and montmorillonite content. In order to optimize the procedure for the characterization of bentonites, correlations between different tests have been done, to identify the most suitable ones. Finally, a compatibility test has been carried out to study the performance of bentonites in water containing a high amount of sales, because in this case, an ion exchange between the interlayer sodium ions of bentonite and cations dissolved in the water can take, resulting in a decrease swell of the bentonite. (Author)

  8. Geophysical characterization of subsurface barriers

    International Nuclear Information System (INIS)

    Borns, D.J.

    1995-08-01

    An option for controlling contaminant migration from plumes and buried waste sites is to construct a subsurface barrier of a low-permeability material. The successful application of subsurface barriers requires processes to verify the emplacement and effectiveness of barrier and to monitor the performance of a barrier after emplacement. Non destructive and remote sensing techniques, such as geophysical methods, are possible technologies to address these needs. The changes in mechanical, hydrologic and chemical properties associated with the emplacement of an engineered barrier will affect geophysical properties such a seismic velocity, electrical conductivity, and dielectric constant. Also, the barrier, once emplaced and interacting with the in situ geologic system, may affect the paths along which electrical current flows in the subsurface. These changes in properties and processes facilitate the detection and monitoring of the barrier. The approaches to characterizing and monitoring engineered barriers can be divided between (1) methods that directly image the barrier using the contrasts in physical properties between the barrier and the host soil or rock and (2) methods that reflect flow processes around or through the barrier. For example, seismic methods that delineate the changes in density and stiffness associated with the barrier represents a direct imaging method. Electrical self potential methods and flow probes based on heat flow methods represent techniques that can delineate the flow path or flow processes around and through a barrier

  9. Effects of carbohydrate/protein ratio on the microstructure and the barrier and sorption properties of wheat starch-whey protein blend edible films.

    Science.gov (United States)

    Basiak, Ewelina; Lenart, Andrzej; Debeaufort, Frédéric

    2017-02-01

    Starch and whey protein isolate and their mixtures were used for making edible films. Moisture sorption isotherms, water vapour permeability, sorption of aroma compounds, microstructure, water contact angle and surface properties were investigated. With increasing protein content, the microstructure changes became more homogeneous. The water vapour permeability increases with both the humidity gradient and the starch content. For all films, the hygroscopicity increases with starch content. Surface properties change according to the starch/whey protein ratio and are mainly related to the polar component of the surface tension. Films composed of 80% starch and 20% whey proteins have more hydrophobic surfaces than the other films due to specific interactions. The effect of carbohydrate/protein ratio significantly influences the microstructure, the surface wettability and the barrier properties of wheat starch-whey protein blend films. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  10. Taxonomic and functional characteristics of microbial communities and their correlation with physicochemical properties of four geothermal springs in Odisha, India.

    Science.gov (United States)

    Badhai, Jhasketan; Ghosh, Tarini S; Das, Subrata K

    2015-01-01

    This study describes microbial diversity in four tropical hot springs representing moderately thermophilic environments (temperature range: 40-58°C; pH: 7.2-7.4) with discrete geochemistry. Metagenome sequence data showed a dominance of Bacteria over Archaea; the most abundant phyla were Chloroflexi and Proteobacteria, although other phyla were also present, such as Acetothermia, Nitrospirae, Acidobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, Thermotogae, Euryarchaeota, Verrucomicrobia, Ignavibacteriae, Cyanobacteria, Actinobacteria, Planctomycetes, Spirochaetes, Armatimonadetes, Crenarchaeota, and Aquificae. The distribution of major genera and their statistical correlation analyses with the physicochemical parameters predicted that the temperature, aqueous concentrations of ions (such as sodium, chloride, sulfate, and bicarbonate), total hardness, dissolved solids and conductivity were the main environmental variables influencing microbial community composition and diversity. Despite the observed high taxonomic diversity, there were only little variations in the overall functional profiles of the microbial communities in the four springs. Genes involved in the metabolism of carbohydrates and carbon fixation were the most abundant functional class of genes present in these hot springs. The distribution of genes involved in carbon fixation predicted the presence of all the six known autotrophic pathways in the metagenomes. A high prevalence of genes involved in membrane transport, signal transduction, stress response, bacterial chemotaxis, and flagellar assembly were observed along with genes involved in the pathways of xenobiotic degradation and metabolism. The analysis of the metagenomic sequences affiliated to the candidate phylum Acetothermia from spring TB-3 provided new insight into the metabolism and physiology of yet-unknown members of this lineage of bacteria.

  11. Taxonomic and functional characteristics of microbial communities and their correlation with physicochemical properties of four geothermal springs in Odisha, India

    Directory of Open Access Journals (Sweden)

    Subrata K Das

    2015-10-01

    Full Text Available This study describes microbial diversity in four tropical hot springs representing moderately thermophilic environments (temperature range: 40-58 °C; pH: 7.2-7.4 with discrete geochemistry. Metagenome sequence data showed a dominance of Bacteria over Archaea; the most abundant phyla were Chloroflexi and Proteobacteria, although other phyla were also present, such as Acetothermia, Nitrospirae, Acidobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, Thermotogae, Euryarchaeota, Verrucomicrobia, Ignavibacteriae, Cyanobacteria, Actinobacteria, Planctomycetes, Spirochaetes, Armatimonadetes, Crenarchaeota, and Aquificae. The distribution of major genera and their statistical correlation analyses with the physicochemical parameters predicted that the temperature, aqueous concentrations of ions (such as sodium, chloride, sulfate, and bicarbonate, total hardness, dissolved solids and conductivity were the main environmental variables influencing microbial community composition and diversity. Despite the observed high taxonomic diversity, there were only little variations in the overall functional profiles of the microbial communities in the four springs. Genes involved in the metabolism of carbohydrates and carbon fixation were the most abundant functional class of genes present in these hot springs. The distribution of genes involved in carbon fixation predicted the presence of all the six known autotrophic pathways in the metagenomes. A high prevalence of genes involved in membrane transport, signal transduction, stress response, bacterial chemotaxis and flagellar assembly were observed along with genes involved in the pathways of xenobiotic degradation and metabolism. The analysis of the metagenomic sequences affiliated to the candidate phylum Acetothermia from spring TB-3 provided new insight into the metabolism and physiology of yet-unknown members of this lineage of bacteria.

  12. Changes in Mineralization Activity of Microbial Communities Depending on Physico-Chemical Properties of Soils and Cadmium Contamination

    Directory of Open Access Journals (Sweden)

    A.R. Gilmullina

    2016-09-01

    Full Text Available The effects of glucose and cadmium addition, as well as their combination on the CO2 efflux from soils, which differed by the total organic carbon content and texture, were studied. Glucose (10 g/kg addition induced an increase in the CO2 efflux from soil and a decrease in the content of dissolved organic carbon. The intensity of this effect reduced in samples with the low total organic carbon content. Cadmium (300 mg/kg addition alone did not affect the studied parameters. In case of combined addition of glucose and cadmium, the mineralization activity of microbial community was mainly determined by glucose amendment.

  13. Physico-chemical, microbial and sensory properties of kunu zaki beverage sweetened with black velvet tamarind (Dialium guineense)

    OpenAIRE

    Abiodun, O. A.; Dauda, A. O.; Adebisi, T. T.; Alonge, C. D.

    2017-01-01

    This work determined the physicochemical, microbial and sensory characteristics of kunu zaki sweetened with black velvet tamarind (Dialium guinnense) flour. The outer covering and seed of black velvet was removed while the pulp was pulverized to obtain the flour. The tamarind pulp was analysed for its proximate and sugar contents. Kunu zaki was prepared according to standard method and 10, 20, 30, 40 and 50 g of the black velvet pulp was added to 1000 ml each of kunu zaki along with a control...

  14. Development and Psychometric Properties of a Survey to Assess Barriers to Implementing Advance Care Planning in Primary Care.

    Science.gov (United States)

    Howard, Michelle; Day, Andrew G; Bernard, Carrie; Tan, Amy; You, John; Klein, Doug; Heyland, Daren K

    2018-01-01

    Valid and reliable measurement of barriers to advance care planning (ACP) in health care settings can inform the design of robust interventions. This article describes the development and psychometric evaluation of an instrument to measure the presence and magnitude of perceived barriers to ACP discussion with patients from the perspective of family physicians. A questionnaire was designed through literature review and expert input, asking family physicians to rate the importance of barriers (0 = not at all a barrier and 6 = an extreme amount) to ACP discussions with patients and administered to 117 physicians. Floor effects and missing data patterns were examined. Item-by-item correlations were examined using Pearson correlation. Exploratory factor analysis was conducted (iterated principle factor analysis with oblique rotation), internal consistency (Cronbach's alpha) overall and within factors was calculated, and construct validity was evaluated by calculating three correlations with related questions that were specified a priori. The questionnaire included 31 questions in three domains relating to the clinician, patient/family and system or external factors. No items were removed due to missing data, floor effects, or high correlation with another item. A solution of three factors accounted for 71% of variance. One item was removed because it did not load strongly on any factor. All other items except one remained in the original domain in the questionnaire. Cronbach's alpha for the three factors ranged from 0.84 to 0.90. Two of three a priori correlations with related questions were statistically significant. This questionnaire to assess barriers to ACP discussion from the perspective of family physicians demonstrates preliminary evidence of reliability and validity. Copyright © 2017 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

  15. Effect of single- and two-cycle high hydrostatic pressure treatments on water properties, physicochemical and microbial qualities of minimally processed squids (todarodes pacificus).

    Science.gov (United States)

    Zhang, Yifeng; Jiao, Shunshan; Lian, Zixuan; Deng, Yun; Zhao, Yanyun

    2015-05-01

    This study investigated the effect of single- and two-cycle high hydrostatic pressure (HHP) treatments on water properties, physicochemical, and microbial qualities of squids (Todarodes pacificus) during 4 °C storage for up to 10 d. Single-cycle treatments were applied at 200, 400, or 600 MPa for 20 min (S-200, S-400, and S-600), and two-cycle treatments consisted of two 10 min cycles at 200, 400, or 600 MPa, respectively (T-200, T-400, and T-600). HHP-treated samples had higher (P pressure level caused no significant difference in water state of squids. The two-cycle HHP treatment was more effective in controlling total volatile basic nitrogen, pH, and total plate counts (TPC) of squids during storage, in which TPC of S-600 and T-600 was 2.9 and 1.8 log CFU/g at 10 d, respectively, compared with 7.5 log CFU/g in control. HHP treatments delayed browning discoloration of the squids during storage, and the higher pressure level and two-cycle HHP were more effective. Water properties highly corresponded with color and texture indices of squids. This study demonstrated that the two-cycle HHP treatment was more effective in controlling microbial growth and quality deterioration while having similar impact on the physicochemical and water properties of squids in comparison with the single-cycle treatment, thus more desirable for extending shelf-life of fresh squids. © 2015 Institute of Food Technologists®

  16. Studies of the effects of gamma irradiation on the microbial load and physicochemical properties of Ghanaian honey from the Ashanti, Brong Ahafo and Greater Accra regions

    International Nuclear Information System (INIS)

    Ansah Larbi, D.

    2015-01-01

    Honey is a universal product with a wide usage throughout the life spectrum. It is a substitute for sugar for many people, an energy booster, helps maintain the blood sugar level and research has shown that it has the potential for cancer prevention. The high sugar concentration of honey and its low pH gives honey antimicrobial properties and makes it difficult for microorganisms to grow. However, research has provided evidence of the presence of microbes in honey. The microbes are introduced into honey through primary and secondary sources. The primary sources are due to honeybee foraging activities resulting in the transfer of pollen and other microbial species in the air, soil and plants into the product before it matures. The secondary sources of contamination are due to the harvesting process, materials used for harvesting and storage of the honey; as well as the method used in extracting and treating honey before it is sold to the consumer. Accordingly, it is imperative that the quality of honey on the Ghanaian market is monitored regularly to provide data on the microbial load. This study endeavours to ascertain the presence of microorganisms in Ghanaian honey, the sources of microbial contamination and the effect of gamma radiation on the microbial load as well as the physico-chemical properties of honey. Ninety (90) honey samples were collected from three regions; Brong Ahafo, Ashanti, and Greater Accra [Thirty (30) from each region]. Sampling was conducted using the farmer-to-retailer route, that is, honey was sampled directly from the beehive with the comb before the farmer harvested, samples were taken after the farmer had harvested and treated and finally honey was sampled from retailers who buy directly from the farmer. The effect of gamma radiation on the microbial load was studied using a 60 Co source gamma irradiation facility at doses of 20 kGy, 30 kGy and 40 kGy on the presence of microbes and the physicochemical properties (pH, Reducing Sugar

  17. Barrier properties of plastic films coated with an Al{sub 2}O{sub 3} layer by roll-to-toll atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Hirvikorpi, Terhi, E-mail: Terhi.Hirvikorpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Laine, Risto, E-mail: Risto.Laine@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vähä-Nissi, Mika, E-mail: Mika.Vaha-Nissi@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kilpi, Väinö, E-mail: Vaino.Kilpi@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Salo, Erkki, E-mail: Erkki.Salo@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Li, Wei-Min, E-mail: Wei-Min.Li@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Lindfors, Sven, E-mail: Sven.Lindfors@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland); Vartiainen, Jari, E-mail: Jari.Vartiainen@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kenttä, Eija, E-mail: Eija.Kentta@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Nikkola, Juha, E-mail: Juha.Nikkola@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1300, FI-33101 Tampere (Finland); Harlin, Ali, E-mail: Ali.Harlin@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, Espoo, P.O. Box 1000, FI-02044 VTT (Finland); Kostamo, Juhana, E-mail: Juhana.Kostamo@picosun.com [Picosun Oy, Tietotie 3, FI-02150 Espoo (Finland)

    2014-01-01

    Thin (30–40 nm) and highly uniform Al{sub 2}O{sub 3} coatings have been deposited at relatively low temperature of 100 °C onto various polymeric materials employing the atomic layer deposition (ALD) technique, both batch and roll-to-roll (R2R) mode. The applications for ALD have long been limited those feasible for batch processing. The work demonstrates that R2R ALD can deposit thin films with properties that are comparable to the film properties fabricated by in batch. This accelerates considerably the commercialization of many products, such as flexible, printed electronics, organic light-emitting diode lighting, third generation thin film photovoltaic devices, high energy density thin film batteries, smart textiles, organic sensors, organic/recyclable packaging materials, and flexible displays, to name a few. - Highlights: • Thin and uniform Al{sub 2}O{sub 3} coatings have been deposited onto polymers materials. • Batch and roll-to-roll (R2R) atomic layer deposition (ALD) have been employed. • Deposition with either process improved the barrier properties. • Sensitivity of coated films to defects affects barrier obtained with R2R ALD.

  18. Time-course correlation of biofilm properties and electrochemical performance in single-chamber microbial fuel cells

    KAUST Repository

    Ren, Zhiyong; Ramasamy, Ramaraja P.; Cloud-Owen, Susan Red; Yan, Hengjing; Mench, Matthew M.; Regan, John M.

    2011-01-01

    The relationship between anode microbial characteristics and electrochemical parameters in microbial fuel cells (MFCs) was analyzed by time-course sampling of parallel single-bottle MFCs operated under identical conditions. While voltage stabilized within 4. days, anode biofilms continued growing during the six-week operation. Viable cell density increased asymptotically, but membrane-compromised cells accumulated steadily from only 9% of total cells on day 3 to 52% at 6. weeks. Electrochemical performance followed the viable cell trend, with a positive correlation for power density and an inverse correlation for anode charge transfer resistance. The biofilm architecture shifted from rod-shaped, dispersed cells to more filamentous structures, with the continuous detection of Geobacter sulfurreducens-like 16S rRNA fragments throughout operation and the emergence of a community member related to a known phenazine-producing Pseudomonas species. A drop in cathode open circuit potential between weeks two and three suggested that uncontrolled biofilm growth on the cathode deleteriously affects system performance. © 2010 Elsevier Ltd.

  19. Synthetic microbial ecology and the dynamic interplay between microbial genotypes.

    Science.gov (United States)

    Dolinšek, Jan; Goldschmidt, Felix; Johnson, David R

    2016-11-01

    Assemblages of microbial genotypes growing together can display surprisingly complex and unexpected dynamics and result in community-level functions and behaviors that are not readily expected from analyzing each genotype in isolation. This complexity has, at least in part, inspired a discipline of synthetic microbial ecology. Synthetic microbial ecology focuses on designing, building and analyzing the dynamic behavior of ‘ecological circuits’ (i.e. a set of interacting microbial genotypes) and understanding how community-level properties emerge as a consequence of those interactions. In this review, we discuss typical objectives of synthetic microbial ecology and the main advantages and rationales of using synthetic microbial assemblages. We then summarize recent findings of current synthetic microbial ecology investigations. In particular, we focus on the causes and consequences of the interplay between different microbial genotypes and illustrate how simple interactions can create complex dynamics and promote unexpected community-level properties. We finally propose that distinguishing between active and passive interactions and accounting for the pervasiveness of competition can improve existing frameworks for designing and predicting the dynamics of microbial assemblages.

  20. Membrane organization determines barrier properties of endothelial cells and short-chain sphingolipid-facilitated doxorubicin influx.

    Science.gov (United States)

    van Hell, A J; Klymchenko, A; Gueth, D M; van Blitterswijk, W J; Koning, G A; Verheij, M

    2014-09-01

    The endothelial lining and its outer lipid membrane are the first major barriers drug molecules encounter upon intravenous administration. Our previous work identified lipid analogs that counteract plasma membrane barrier function for a series of amphiphilic drugs. For example, short-chain sphingolipids (SCS), like N-octanoyl-glucosylceramide, effectively elevated doxorubicin accumulation in tumor cells, both in vitro and in vivo, and in endothelial cells, whereas other (normal) cells remained unaffected. We hypothesize here that local membrane lipid composition and the degree of lipid ordering define SCS efficacy in individual cells. To this end, we study the differential effect of SCS on bovine aortic endothelial cells (BAEC) in its confluent versus proliferative state, as a model system. While their (plasma membrane) lipidome stays remarkably unaltered when BAECs reach confluency, their lipids segregate to form apical and basolateral domains. Using probe NR12S, we reveal that lipids in the apical membrane are more condensed/liquid-ordered. SCS preferentially attenuate the barrier posed by these condensed membranes and facilitate doxorubicin influx in these particular membrane regions. We confirm these findings in MDCK cells and artificial membranes. In conclusion, SCS-facilitated drug traversal acts on condensed membrane domains, elicited by confluency in resting endothelium. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. The role of temperature ramp-up time before barrier layer growth in optical and structural properties of InGaN/GaN multi-quantum wells

    Science.gov (United States)

    Xing, Yao; Zhao, Degang; Jiang, Desheng; Liu, Zongshun; Zhu, Jianjun; Chen, Ping; Yang, Jing; Liu, Wei; Liang, Feng; Liu, Shuangtao; Zhang, Liqun; Wang, Wenjie; Li, Mo; Zhang, Yuantao; Du, Guotong

    2018-05-01

    In InGaN/GaN multi-quantum wells (MQWs), a low temperature cap (LT-cap) layer is grown between the InGaN well layer and low temperature GaN barrier layer. During the growth, a temperature ramp-up and ramp-down process is added between LT-cap and barrier layer growth. The effect of temperature ramp-up time duration on structural and optical properties of quantum wells is studied. It is found that as the ramp-up time increases, the Indium floating layer on the top of the well layer can be diminished effectively, leading to a better interface quality between well and barrier layers, and the carrier localization effect is enhanced, thereby the internal quantum efficiency (IQE) of QWs increases surprisingly. However, if the ramp-up time is too long, the carrier localization effect is weaker, which may increase the probabilities of carriers to meet with nonradiative recombination centers. Meanwhile, more nonradiative recombination centers will be introduced into well layers due to the indium evaporation. Both of them will lead to a reduction of internal quantum efficiency (IQE) of MQWs.

  2. Magnetic properties and potential barrier between crystallites model of MgGa{sub 2-x}Fe{sub x}O{sub 4} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Ribeiro, V.A. dos S.; Rubinger, R.M.; Oliveira, A.F.; Mendonca, C.S.P.; Silva, M.R. da, E-mail: vanderalkmin@gmail.com, E-mail: rero@unifei.edu.br, E-mail: adhimarflavio@unifei.edu.br, E-mail: sales.claudiney21@gmail.com, E-mail: mrsilva@unifei.edu.br [Universidade Federal de Itajuba (UNIFEI), MG (Brazil). Instituto de Fisica e Quimica

    2016-10-15

    The aim of this work was to investigate the magnetic properties and the electrical conductivity temperature dependence associated to the potential barrier between the crystallites model. Gallium and magnesium containing spinel ceramic has low magnetic coercivity and high electrical resistivity. MgGa{sub 2-x}Fe{sub x}O{sub 4} samples (x= 0.01, 0.05, 0.15, 0.25, 0.35) were prepared by solid-state method and sintered at 800 °C for 8 h. X-ray diffraction analysis confirmed the formation of a single phase with compact cubic spinel structure. The magnetic measurements show that the saturation magnetization and remanence of all samples increased with increasing iron concentration. The coercive field decreased up to the concentration x= 0.15, and above x= 0.25 it was observed an increase in the coercive field. Through electrical characterization it was found that the samples presented highly insulating behavior for x= 0.01, and further increase in x above 0.15 gives a semiconductor behavior compatible with the potential barrier between the crystallites model, i.e. fulfills the condition L/2 > L{sub D} (crystallite size L in comparison with the Debye length L{sub D}), and the conduction is limited by potential barriers between the crystallites. (author)

  3. Does nitrogen fertilization history affects short-term microbial responses and chemical properties of soils submitted to different glyphosate concentrations?

    Directory of Open Access Journals (Sweden)

    Elodie Nivelle

    Full Text Available The use of nitrogen (N fertilizer and glyphosate-based herbicides is increasing worldwide, with agriculture holding the largest market share. The agronomic and socioeconomic utilities of glyphosate are well established; however, our knowledge of the potential effects of glyphosate applied in the presence or absence of long-term N fertilization on microbial functional activities and the availability of soil nutrients remains limited. Using an ex situ approach with soils that did (N+ or did not (N0 receive synthetic N fertilization for 6 years, we assessed the impact of different rates (no glyphosate, CK; field rate, FR; 100 × field rate, 100FR of glyphosate application on biological and chemical parameters. We observed that, after immediate application (1 day, the highest dose of glyphosate (100FR negatively affected the alkaline phosphatase (AlP activity in soils without N fertilization history and decreased the cation exchange capacity (CEC in N0 compared to CK and FR treatments with N+. Conversely, the 100FR application increased nitrate (NO3- and available phosphorus (PO43- regardless of N fertilization history. Then, after 8 and 15 days, the N+\\100FR and N+\\FR treatments exhibited the lowest values for dehydrogenase (DH and AlP activities, respectively, while urease (URE activity was mainly affected by N fertilization. After 15 days and irrespective of N fertilization history, the FR glyphosate application negatively affected the degradation of carbon substrates by microbial communities (expressed as the average well color development, AWCD. By contrast, the 100FR treatment positively affected AWCD, increasing PO43- by 5 and 16% and NO3- by 126 and 119% in the N+ and N0 treatments, respectively. In addition, the 100FR treatment resulted in an increase in the average net nitrification rate. Principal component analysis revealed that the 100FR glyphosate treatment selected microbial communities that were able to metabolize amine substrates

  4. Comparative Study of Microbial Activity and Chemical Properties of Soil by Implementing Anti-erosion Measure Vertical Mulching with Organic Residues

    Directory of Open Access Journals (Sweden)

    Gergana Slavova Kuncheva

    2015-01-01

    Full Text Available Water soil erosion is a phenomenon in which soil particles are separated transported and translocated by the action of rain water. Removal of topsoil by water flow leads to a decrease of humus in the soil, deterioration of soil structure, compaction, and reduction of microbial activity.Developed and tested have been number of methods and technologies for soil protection from the effects of water erosion. Such technology is vertical mulching, and straw or compost applied as mulching material.This work is a study of the changes that occur in some soil chemical properties and soil microbiological activity, as a result in the implementation of anti-erosion measure vertical mulching with different mulching materials for growing corn and wheat grain on carbonate chernozem, on sloping agricultural lands.

  5. Short-time effect of salvage harvesting on microbial soil properties in a Mediterranean area affected by a wildfire: preliminary results

    Science.gov (United States)

    Moltó, Jorge; Mataix-Solera, Jorge; Arcenegui, Victoria; Morugan, Alicia; Girona, Antonio; Garcia-orenes, Fuensanta

    2014-05-01

    In the Mediterranean region, wildfires are considered one of the main ecological factors, which, in addition to and in relation to changes in soil use, may cause soil loss and degradation, one of the most important environmental problems that humanity must face up to. As is well known, the soil-plant system is one of the key factors determining ecological recovery after the occurrence of a wildfire. Traditionally, a variety of forestry practices have been implemented on spanish sites after the incidence of a wildfire. Among them stands out the complete extraction of the burned wood, which consist in getting rid of the branches and other wooden debris using small controlled bonfires, splintering or mechanical extraction. This set of post-fire management practices is known as salvage logging or salvage harvesting. Despite the remarkable relevance and influence that this conjunction of techniques has on land management after a wildfire, very little experimental research focused on assessing the impact of salvage logging on the vegetal community has been done. Furthermore, even less research inquiring into the mode and grade of incidence that the salvage logging produces on soil properties has taken place. The aim of this research is to assess the effects that the salvage harvesting has on different soil microbial properties and other related properties. The study area is located in the Natural Park of the "Sierra de Mariola" in the province of Alicante, southeastern Spain. This location was affected by a wildfire whose extension reached more than 500 Ha in July 2012. Different post-fire treatments were proposed by the authorities, including salvage harvesting in some areas. Two different treatments were distinguished for the study, "control" (without any kind of burned wood removal) and "harvest" (where salvage logging was carried out), in each area three 4 m2 sampling plots were set up. These two treatments were established on the same slope with the same orography

  6. In-Drift Microbial Communities

    Energy Technology Data Exchange (ETDEWEB)

    D. Jolley

    2000-11-09

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses.

  7. In-Drift Microbial Communities

    International Nuclear Information System (INIS)

    Jolley, D.

    2000-01-01

    As directed by written work direction (CRWMS M and O 1999f), Performance Assessment (PA) developed a model for microbial communities in the engineered barrier system (EBS) as documented here. The purpose of this model is to assist Performance Assessment and its Engineered Barrier Performance Section in modeling the geochemical environment within a potential repository drift for TSPA-SR/LA, thus allowing PA to provide a more detailed and complete near-field geochemical model and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near Field Environment (NFE) Revision 2 (NRC 1999). This model and its predecessor (the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document, CRWMS M and O 1998a) was developed to respond to the applicable KTIs. Additionally, because of the previous development of the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a), the M and O was effectively able to resolve a previous KTI concern regarding the effects of microbial processes on seepage and flow (NRC 1998). This document supercedes the in-drift microbial communities model as documented in Chapter 4 of the TSPA-VA Technical Basis Document (CRWMS M and O 1998a). This document provides the conceptual framework of the revised in-drift microbial communities model to be used in subsequent performance assessment (PA) analyses

  8. Microbial inactivation of paprika by a high-temperature short-X time treatment. Influence on color properties.

    Science.gov (United States)

    Almela, Luis; Nieto-Sandoval, José M; Fernández López, José A

    2002-03-13

    High-temperature short-time (HTST) treatments have been used to destroy the bioburden of paprika. With this in mind, we have designed a device to treat samples of paprika with a gas whose temperature, pressure, and composition can be selected. Temperatures and treatment times ranged from 130 to 170 degrees C and 4 to 6 s, respectively. The survival of the most commonly found microorganisms in paprika and any alteration in extractable and superficial color were examined. Data showed that the optimum HTST conditions were 145 degrees C, 1.5 kg/cm2 of overpressure, 6 s operation time, and a thermal fluid of saturated steam. No microbial growth was detected during storage after thermal treatment. To minimize the color losses, treated (HTST) paprika samples should be kept under refrigeration.

  9. Design of engineered sorbent barriers

    International Nuclear Information System (INIS)

    Jones, E.O.; Freeman, H.D.

    1988-08-01

    A sorbent barrier uses sorbent material such as activated carbon or natural zeolites to prevent the migration of radionuclides from a low-level waste site to the aquifer. The sorbent barrier retards the movement of radioactive contaminants, thereby providing time for the radionuclides to decay. Sorbent barriers can be a simple, effective, and inexpensive method for reducing the migration of radionuclides to the environment. Designing a sorbent barrier consists of using soil and sorbent material properties and site conditions as input to a model which will determine the necessary sorbent barrier thickness to meet contaminant limits. The paper will cover the following areas: techniques for measuring sorption properties of barrier materials and underlying soils, use of a radionuclide transport model to determine the required barrier thickness and performance under a variety of site conditions, and cost estimates for applying the barrier. 8 refs., 6 figs., 1 tab

  10. Design of engineered sorbent barriers

    International Nuclear Information System (INIS)

    Jones, E.O.; Freeman, H.D.

    1988-01-01

    A sorbent barrier uses sorbent material such as activated carbon or natural zeolites to prevent the migration of radionuclides from a low-level waste site to the aquifer. The sorbent barrier retards the movement of radioactive contaminants, thereby providing time for the radionuclides to decay. Sorbent barriers can be a simple, effective, and inexpensive method for reducing the migration of radionuclides to the environment. Designing a sorbent barrier consists of using soil and sorbent material properties and site conditions as input to a model which will determine the necessary sorbent barrier thickness to meet contaminant limits. The paper covers the following areas: techniques for measuring sorption properties of barrier materials and underlying soils, use of a radionuclide transport model to determine the required barrier thickness and performance under a variety of site conditions, and cost estimates for applying the barrier

  11. Effect of sodium lactate /sodium diacetate in combination with sodium nitrite on physiochemical, microbial properties and sensory evaluation of cow sausage

    Directory of Open Access Journals (Sweden)

    Habib Sedghi

    2014-11-01

    Full Text Available Sodium nitrite has been always considered as one of the common additives due to its antibacterial effects on Clostridium botulinum and meat products' color, however it produces cancer creating nitrosamine. Recently, organic acids and their salts such as lactates have been employed as antimicrobial compounds. Lactates also improve organileptic properties including color, texture and taste and antioxidant properties. Sodium lactate causes to more reduction of anaerobic spore former bacteria than nitrite, inhibits botulin produced by Clostridium botulinum. Sodium lactate produces a permanent reddish pink color through reduction of deoxymygloboline and producing deoxymyoglobuline. In this study, the decrease of sodium nitrite amount from 120ppm to 15ppm by adding sodium lactate / sodium diacetate led to achieve an acceptable product. The best results revealed through adding 3.0625% of sodium lactate / sodium diacetate in combination with 30ppm sodium nitrite. Results also exhibited more reduction of pathogens' growth than nitrite, enhanced flavor slightly, but unable to produce reddish pink color as produced by nitrite. Results also exhibited that sodium lactate / diacetate cause to retard in microbial growth, reducing chemical change, enhance sensory properties, partially improvement in taste and texture. Although inappropriate color demonstrated sodium lactate / diacetate's inability in red pink color production in 4th sample (contains 15 ppm nitrite, its synergy effect in combination with sodium nitrite on nitroso myoglobuline production has been proven, led to sodium nitrite reduction in sausages.

  12. Mechanical Properties and Real-Time Damage Evaluations of Environmental Barrier Coated SiC/SiC CMCs Subjected to Tensile Loading Under Thermal Gradients

    Science.gov (United States)

    Appleby, Matthew; Zhu, Dongming; Morscher, Gregory

    2015-01-01

    SiC/SiC ceramic matrix composites (CMCs) require new state-of-the art environmental barrier coatings (EBCs) to withstand increased temperature requirements and high velocity combustion corrosive combustion gasses. The present work compares the response of coated and uncoated SiC/SiC CMC substrates subjected to simulated engine environments followed by high temperature mechanical testing to asses retained properties and damage mechanisms. Our focus is to explore the capabilities of electrical resistance (ER) measurements as an NDE technique for testing of retained properties under combined high heat-flux and mechanical loading conditions. Furthermore, Acoustic Emission (AE) measurements and Digital Image Correlation (DIC) were performed to determine material damage onset and accumulation.

  13. THE EFFECT OF PLASTICIZER CONTENT AND DISACCHARIDE TYPE ON THE MECHANICAL, BARRIER AND PHYSICAL PROPERTIES OF BOVINE GELATIN-BASED FILMS

    Directory of Open Access Journals (Sweden)

    PEDRO GUERRERO1

    2014-06-01

    Full Text Available Gelatins are regarded as alternative raw materials to prepare films for food packaging. However, the improvement of their mechanical and water barrier properties is necessary in order to obtain useful materials in service conditions. To improve these functional properties, two strategies have been carried out in this work. First, glycerol was added as plasticizer to increase the flexibility of the films. Second, lactose or sucrose was added to react with gelatin and increase water resistance of gelatin-based films. Commercial gelatin, glycerol and lactose or sucrose were employed in this work and processing of the films was carried out by solution casting. All gelatin films obtained were transparent and flexible. Moreover, the hydrophobic character of the films was increased and the film solubility was decreased by the addition of glycerol and disaccharides. As was observed via FTIR, the changes were due to the interactions between gelatin and glycerol and Maillard reaction between gelatin and disaccharides.

  14. From Nanofibrillar to Nanolaminar Poly(butylene succinate): Paving the Way to Robust Barrier and Mechanical Properties for Full-Biodegradable Poly(lactic acid) Films.

    Science.gov (United States)

    Xie, Lan; Xu, Huan; Chen, Jing-Bin; Zhang, Zi-Jing; Hsiao, Benjamin S; Zhong, Gan-Ji; Chen, Jun; Li, Zhong-Ming

    2015-04-22

    The traditional approach toward barrier property enhancement of poly(lactic acid) (PLA) is the incorporation of sheet-like fillers such as nanoclay and graphene, unfortunately leading to the sacrificed biocompatibility and degradability. Here we unveil the first application of a confined flaking technique to establish the degradable nanolaminar poly(butylene succinate) (PBS) in PLA films based on PLA/PBS in situ nanofibrillar composites. The combination of high pressure (10 MPa) and appropriate temperature (160 °C) during the flaking process desirably enabled sufficient deformation of PBS nanofibrils and retention of ordered PLA channels. Particularly, interlinked and individual nanosheets were created in composite films containing 10 and 20 wt % PBS, respectively, both of which presented desirable alignment and large width/thickness ratio (nanoscale thickness with a width of 428±13.1 and 76.9±8.2 μm, respectively). With the creation of compact polymer "nano-barrier walls", a dramatic decrease of 86% and 67% in the oxygen permeability coefficient was observed for the film incorporated with well-organized 20 wt % PBS nanosheets compared to pure PLA and pure PBS (1.4 and 0.6×10(-14) cm3·cm·cm(-2)·s(-1)·Pa(-1)), respectively. Unexpectedly, prominent increases of 21% and 28% were achieved in the tensile strength and modulus of composite films loaded 20 wt % PBS nanosheets compared to pure PLA films, although PBS intrinsically presents poor strength and stiffness. The unusual combination of barrier and mechanical performances established in the fully degradable system represent specific properties required in packaging beverages, food and medicine.

  15. Molecular Characterization of Barrier Properties in Follicle-Associated Epithelium of Porcine Peyer's Patches Reveals Major Sealing Function of Claudin-4

    Directory of Open Access Journals (Sweden)

    Judith Radloff

    2017-08-01

    Full Text Available The pig represents a preferred model for the analysis of intestinal immunology. However, the barrier of the follicle-associated epithelium (FAE covering porcine Peyer's patches (PP has not yet been characterized in detail. This study aimed to perform this characterization in order to pave the way toward an understanding of the functional contribution of epithelial barrier properties in gut immunology. Porcine tissue specimens were taken from the distal small intestine in order to obtain electrophysiological data of PP FAE and neighboring villous epithelium (VE, employing the Ussing chamber technique. Transepithelial resistance (TER and paracellular fluorescein flux were measured, and tissues were morphometrically compared. In selfsame tissues, expression and localization of major tight junction (TJ proteins (claudin-1, -2, -3, -4, -5, and -8 were analyzed. PP FAE specimens showed a higher TER and a lower apparent permeability for sodium fluorescein than VE. Immunoblotting revealed an expression of all claudins within both epithelia, with markedly stronger expression of the sealing TJ protein claudin-4 in PP FAE compared with the neighboring VE. Immunohistochemistry confirmed the expression and localization of all claudins in both PP FAE and VE, with stronger claudin-4 abundance in PP FAE. The results are in accordance with the physiological function of the FAE, which strongly regulates and limits antigen uptake determining a mandatory transcellular route for antigen presentation, highlighting the importance of this structure for the first steps of the intestinal immune response. Thus, this study provides detailed insights into the specific barrier properties of the porcine FAE covering intestinal PP, at the interface of intestinal immunology and barriology.

  16. Electronic and transport properties of noncollinear magnetic monatomic Mn chains: Fano resonances in the superlattice of noncollinear magnetic barriers and magnetic anisotropic bands

    International Nuclear Information System (INIS)

    Dai, C.J.; Yan, X.H.; Xiao, Y.; Guo, Y.D.

    2015-01-01

    By means of the density functional theory combined with non-equilibrium Green's function method, ballistic transport properties of one-dimensional noncollinear magnetic monatomic chains were investigated using the single-atomic Mn chains as a model system. Fano resonances are found to exist in the monatomic Mn chains with spin-spiral structure. Furthermore, in the monatomic Mn chains with magnetic soliton lattice, Fano resonances are enhanced and cause the conductance splitting in the transmission spectra. The Fano resonances in the noncollinear magnetic single-atomic Mn chains are arising from the coupling of the localized d-states and the extended states of the quantum channels. By constructing a theoretical model and calculating its conductance, it is found that the phenomena of Fano resonances and the accompanying conductance splitting exist universally in the superlattice of one-dimensional noncollinear magnetic barriers, due to the interference of the incident waves and reflected waves by the interfaces between the neighboring barriers. Moreover, the band structures of the ferromagnetic and spin-spiral monatomic Mn chains exhibit a strong dependence on the spatial arrangement of the magnetic moments of Mn atoms when spin–orbit coupling is considered. - Highlights: • Transport properties of noncollinear magnetic monatomic Mn chains are studied. • Fano resonances are found in the noncollinear magnetic monatomic Mn chains. • Magnetic soliton lattice leads to conductance splitting in the transmission curve. • Fano resonances exist in the superlattice of noncollinear magnetic barriers. • Effect of SOC on the band structure of FM and spin-spiral Mn chains are studied

  17. Tuning the electronic properties and Schottky barrier height of the vertical graphene/MoS2 heterostructure by an electric gating

    Science.gov (United States)

    Nguyen, Chuong V.

    2018-04-01

    In this paper, the electronic properties and Schottky contact in graphene/MoS2 (G/MoS2) heterostructure under an applied electric field are investigated by means of the density functional theory. It can be seen that the electronic properties of the G/MoS2 heterostructure are preserved upon contacting owing to the weak van der Waals interaction. We found that the n-type Schottky contact is formed in the G/MoS2 heterostructure with the Schottky barrier height of 0.49 eV. Furthermore, both Schottky contact and Schottky barrier height in the G/MoS2 heterostructure could be controlled by the applied electric field. If a positive electric field of 4 V/nm is applied to the system, a transformation from the n-type Schottky contact to the p-type one was observed, whereas the system keeps an n-type Schottky contact when a negative electric field is applied. Our results may provide helpful information to design, fabricate, and understand the physics mechanism in the graphene-based two-dimensional van der Waals heterostructures like as G/MoS2 heterostructure.

  18. Development of novel zein-sodium caseinate nanoparticle (ZP)-stabilized emulsion films for improved water barrier properties via emulsion/solvent evaporation.

    Science.gov (United States)

    Wang, Li-Juan; Yin, Ye-Chong; Yin, Shou-Wei; Yang, Xiao-Quan; Shi, Wei-Jian; Tang, Chuan-He; Wang, Jin-Mei

    2013-11-20

    This work attempted to develop novel high barrier zein/SC nanoparticle (ZP)-stabilized emulsion films through microfluidic emulsification (ZPE films) or in combination with solvent (ethyl acetate) evaporation techniques (ZPE-EA films). Some physical properties, including tensile and optical properties, water vapor permeability (WVP), and surface hydrophobicity, as well as the microstructure of ZP-stabilized emulsion films were evaluated and compared with SC emulsion (SCE) films. The emulsion/solvent evaporation approach reduced lipid droplets of ZP-stabilized emulsions, and lipid droplets of ZP-stabilized emulsions were similar to or slightly lower than that of SC emulsions. However, ZP- and SC-stabilized emulsion films exhibited a completely different microstructure, nanoscalar lipid droplets were homogeneously distributed in the ZPE film matrix and interpenetrating protein-oil complex networks occurred within ZPE-EA films, whereas SCE films presented a heterogeneous microstructure. The different stabilization mechanisms against creaming or coalescence during film formation accounted for the preceding discrepancy of the microstructures between ZP-and SC-stabilized emulsion films. Interestingly, ZP-stabilized emulsion films exhibited a better water barrier efficiency, and the WVP values were only 40-50% of SCE films. A schematic representation for the formation of ZP-stabilized emulsion films was proposed to relate the physical performance of the films with their microstructure and to elucidate the possible forming mechanism of the films.

  19. Radiolysis products and sensory properties of electron-beam-irradiated high-barrier food-packaging films containing a buried layer of recycled low-density polyethylene.

    Science.gov (United States)

    Chytiri, S D; Badeka, A V; Riganakos, K A; Kontominas, M G

    2010-04-01

    The aim was to study the effect of electron-beam irradiation on the production of radiolysis products and sensory changes in experimental high-barrier packaging films composed of polyamide (PA), ethylene-vinyl alcohol (EVOH) and low-density polyethylene (LDPE). Films contained a middle buried layer of recycled LDPE, while films containing 100% virgin LDPE as the middle buried layer were taken as controls. Irradiation doses ranged between zero and 60 kGy. Generally, a large number of radiolysis products were produced during electron-beam irradiation, even at the lower absorbed doses of 5 and 10 kGy (approved doses for food 'cold pasteurization'). The quantity of radiolysis products increased with irradiation dose. There were no significant differences in radiolysis products identified between samples containing a recycled layer of LDPE and those containing virgin LDPE (all absorbed doses), indicating the 'functional barrier' properties of external virgin polymer layers. Sensory properties (mainly taste) of potable water were affected after contact with irradiated as low as 5 kGy packaging films. This effect increased with increasing irradiation dose.

  20. Influence of the simultaneous addition of bentonite and cellulose fibers on the mechanical and barrier properties of starch composite-films.

    Science.gov (United States)

    de Moraes, J Oliveira; Müller, C M O; Laurindo, J B

    2012-02-01

    The addition of nanoclay or cellulose fibers has been presented in the literature as a suitable alternative for reinforcing starch films. The aim of the present work was to evaluate the effect of the simultaneous incorporation of nanoclay (bentonite) and cellulose fibers on the mechanical and water barrier properties of the resultant composite-films. Films were prepared by casting with 3% in weight of cassava starch, using glycerol as plasticizer (0.30 g per g of starch), cellulose fibers at a concentration of 0.30 g of fibers per g of starch and nanoclay (0.05 g clay per g starch and 0.10 g clay per g starch). The addition of cellulose fibers and nanoclay increased the tensile strength of the films 8.5 times and the Young modulus 24 times but reduced the elongation capacity 14 times. The water barrier properties of the composite-films to which bentonite and cellulose fibers were added were approximately 60% inferior to those of starch films. Diffractograms showed that the nanoclay was intercalated in the polymeric matrix. These results indicate that the simultaneous addition of bentonite and cellulose fibers is a suitable alternative to increase the tensile strength of the films and decrease their water vapor permeabilities.

  1. Formation of a barrier to groundwater contaminants by the injection of zero-valent iron colloids: Suspension properties

    International Nuclear Information System (INIS)

    Kaplan, D.I.; Cantrell, K.J.; Wietsma, T.W.

    1994-01-01

    Zero-valent iron (Fe 0 ) (metallic iron) is a strong chemical reductant that is capable of degrading several halogenated-hydrocarbon compounds (e.g., trichloroethene and tetrachloroethene) and chemically reducing several highly mobile oxidized oxyanions and oxycations to their immobile forms. A series of studies was undertaken to develop methods of injecting micrometer-sized Fe 0 colloids into the subsurface environment to form a chemical barrier to these highly mobile contaminants. Forming a barrier by means of this technique may have the distinct advantage over traditional trench-and-fill technologies: it may be safer, more cost-effective, and may be used at greater depths. Several commercially available Fe 0 colloids were evaluated. One type was selected for further study based on its small size (1 to 2 microm) and the presence of an organic coating. This organic coating was weathered away within 7 days by Hanford ground water (CaCO 3 system, pH 8.1) and exposed the chemically active Fe 0 -colloid surface. Through the use of surfactants in a low ionic strength solution, the length of time that these extremely dense (7.8 g cm -3 ) colloids remained in suspension increased as much as 250%. The efficiency of quartz-sand columns to remove surfactant-coated Fe 0 colloids appeared to be at least partially controlled by injection rate; the filter coefficient values at injection rates of 6, 124, and 248 ml min -1 were 0.30, 0.05, and 0.02 cm -1 , respectively. Studies are underway to develop further understanding of this relationship and to determine the interactive effect of influent colloid concentration and injection flow rate on colloid placement in aquifer sediments for barrier formation

  2. Unraveling the interplay between hydrogen bonding and rotational energy barrier to fine-tune the properties of triazine molecular glasses.

    Science.gov (United States)

    Laventure, Audrey; De Grandpré, Guillaume; Soldera, Armand; Lebel, Olivier; Pellerin, Christian

    2016-01-21

    Mexylaminotriazine derivatives form molecular glasses with outstanding glass-forming ability (GFA), high resistance to crystallization (glass kinetic stability, GS), and a glass transition temperature (Tg) above room temperature that can be conveniently modulated by selection of the headgroup and ancillary groups. A common feature of all these compounds is their secondary amino linkers, suggesting that they play a critical role in their GFA and GS for reasons that remain unclear because they can simultaneously form hydrogen (H) bonds and lead to a high interconversion energy barrier between different rotamers. To investigate independently and better control the influence of H bonding capability and rotational energy barrier on Tg, GFA and GS, a library of twelve analogous molecules was synthesized with different combinations of NH, NMe and O linkers. Differential scanning calorimetry (DSC) revealed that these compounds form, with a single exception, kinetically stable glasses with Tg values spanning a very broad range from -25 to 94 °C. While variable temperature infrared spectroscopy combined to chemometrics reveals that, on average, around 60% of the NH groups are still H-bonded as high as 40 °C above Tg, critical cooling rates obtained by DSC clearly show that molecules without H-bond donating linkers also present an outstanding GFA, meaning that H bonding plays a dominant role in controlling Tg but is not required to prevent crystallization. It is a high interconversion energy barrier, provoking a distribution of rotamers, that most efficiently promotes both GFA and resistance to crystallization. These new insights pave the way to more efficient glass engineering by extending the possible range of accessible Tg, allowing in particular the preparation of homologous glass-formers with high GS at ambient temperature in either the viscous or vitreous state.

  3. Changes of microbial spoilage, lipid-protein oxidation and physicochemical properties during post mortem refrigerated storage of goat meat.

    Science.gov (United States)

    Sabow, Azad Behnan; Sazili, Awis Qurni; Aghwan, Zeiad Amjad; Zulkifli, Idrus; Goh, Yong Meng; Ab Kadir, Mohd Zainal Abidin; Nakyinsige, Khadijah; Kaka, Ubedullah; Adeyemi, Kazeem Dauda

    2016-06-01

    Examined was the effect of post mortem refrigerated storage on microbial spoilage, lipid-protein oxidation and physicochemical traits of goat meat. Seven Boer bucks were slaughtered, eviscerated and aged for 24 h. The Longissimus lumborum (LL) and Semitendinosus (ST) muscles were excised and subjected to 13 days post mortem refrigerated storage. The pH, lipid and protein oxidation, tenderness, color and drip loss were determined in LL while microbiological analysis was performed on ST. Bacterial counts generally increased with increasing aging time and the limit for fresh meat was reached at day 14 post mortem. Significant differences were observed in malondialdehyde (MDA) content at day 7 of storage. The thiol concentration significantly reduced as aging time increased. The band intensities of myosin heavy chain (MHC) and troponin-T significantly decreased as storage progressed, while actin remained relatively stable. After 14 days of aging, tenderness showed significant improvement while muscle pH and drip loss reduced with increase in storage time. Samples aged for 14 days had higher lightness (P goat meat. © 2016 Japanese Society of Animal Science.

  4. Chemical, microbial and physical properties of manufactured soils produced by co-composting municipal green waste with coal fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Belyaeva, O.N.; Haynes, R.J. [University of Queensland, St Lucia, Qld. (Australia)

    2009-11-15

    Increasing proportions of coal fly ash were co-composted with municipal green waste to produce manufactured soil for landscaping use. Only the 100% green waste treatment reached a thermophilic composting phase ({ge} 50{sup o}C) which lasted for 6 days. The 25% and 50% ash treatments reached 36-38{sup o}C over the same period while little or no self-heating occurred in the 75% and 100% ash treatments. Composted green waste had a low bulk density and high total and macro-porosity. Addition of 25% ash to green waste resulted in a 75% increase in available water holding capacity. As the proportions of added ash in the composts increased, the organic C, soluble C, microbial biomass C, basal respiration and activities of beta-glucosidase, L-asparaginase, alkali phosphatase and arylsulphatase enzymes in the composted products all decreased. It could be concluded that addition of fly ash to green waste at a proportion higher than 25% did not improve the quality parameters of manufactured soil.

  5. Effect of gamma irradiation on microbial load, chemical and sensory properties of chicken kabab and sausage; as prepared chilled meals

    International Nuclear Information System (INIS)

    Al-Bachir, M.

    2009-05-01

    Chicken kabab and sausage were treated with 0, 2, 4 or 6 kGy doses of gamma irradiation in a 60 CO package irradiator. Treated and untreated samples were kept in a refrigerator (1-4 degree centigrade). Microbiological, chemical and sensory characteristics of chicken kabab and sausage were evaluated at 0, 1, 2, 3, 4, and 5 months of storage. Proximate composition and sensory evaluation of the chicken kabab and sausage were also investigated, but only immediately after treatment. Irradiation did not influence the major constituents of chicken kabab and sausage (moisture, protein and fats). Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab and sausage. The dose needed to decrease by 1 log cfu/g (D 1 0 value) of Salmonella spp and E coli. numbers were 213 and 400 Gy in chicken kabab, while 345 and 250 Gy in chicken sausage, respectively. The chemical parameters, total acidity, volatile basic nitrogen (VBN), and thiobarbituric acid reactive substances (TBARS), which were chosen as the indices of freshness, were all well within the acceptable limit for up to 5 months for chicken kabab and sausage treated with 4 and 6 kGy. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples. (author)

  6. Influence of Chemical and Physical Properties of Activated Carbon Powders on Oxygen Reduction and Microbial Fuel Cell Performance

    KAUST Repository

    Watson, Valerie J.

    2013-06-03

    Commercially available activated carbon (AC) powders made from different precursor materials (coal, peat, coconut shell, hardwood, and phenolic resin) were electrochemically evaluated as oxygen reduction catalysts and tested as cathode catalysts in microbial fuel cells (MFCs). AC powders were characterized in terms of surface chemistry and porosity, and their kinetic activities were compared to carbon black and platinum catalysts in rotating disk electrode (RDE) tests. Cathodes using the coal-derived AC had the highest power densities in MFCs (1620 ± 10 mW m-2). Peat-based AC performed similarly in MFC tests (1610 ± 100 mW m-2) and had the best catalyst performance, with an onset potential of Eonset = 0.17 V, and n = 3.6 electrons used for oxygen reduction. Hardwood based AC had the highest number of acidic surface functional groups and the poorest performance in MFC and catalysis tests (630 ± 10 mW m-2, Eonset = -0.01 V, n = 2.1). There was an inverse relationship between onset potential and quantity of strong acid (pKa < 8) functional groups, and a larger fraction of microporosity was negatively correlated with power production in MFCs. Surface area alone was a poor predictor of catalyst performance, and a high quantity of acidic surface functional groups was determined to be detrimental to oxygen reduction and cathode performance. © 2013 American Chemical Society.

  7. A High-Throughput Screening Platform of Microbial Natural Products for the Discovery of Molecules with Antibiofilm Properties against Salmonella

    Science.gov (United States)

    Paytubi, Sonia; de La Cruz, Mercedes; Tormo, Jose R.; Martín, Jesús; González, Ignacio; González-Menendez, Victor; Genilloud, Olga; Reyes, Fernando; Vicente, Francisca; Madrid, Cristina; Balsalobre, Carlos

    2017-01-01

    In this report, we describe a High-Throughput Screening (HTS) to identify compounds that inhibit biofilm formation or cause the disintegration of an already formed biofilm using the Salmonella Enteritidis 3934 strain. Initially, we developed a new methodology for growing Salmonella biofilms suitable for HTS platforms. The biomass associated with biofilm at the solid-liquid interface was quantified by staining both with resazurin and crystal violet, to detect living cells and total biofilm mass, respectively. For a pilot project, a subset of 1120 extracts from the Fundación MEDINA's collection was examined to identify molecules with antibiofilm activity. This is the first validated HTS assay of microbial natural product extracts which allows for the detection of four types of activities which are not mutually exclusive: inhibition of biofilm formation, detachment of the preformed biofilm and antimicrobial activity against planktonic cells or biofilm embedded cells. Currently, several extracts have been selected for further fractionation and purification of the active compounds. In one of the natural extracts patulin has been identified as a potent molecule with antimicrobial activity against both, planktonic cells and cells within the biofilm. These findings provide a proof of concept that the developed HTS can lead to the discovery of new natural compounds with antibiofilm activity against Salmonella and its possible use as an alternative to antimicrobial therapies and traditional disinfectants. PMID:28303128

  8. Structural properties of MBE AlInN and AlGaInN barrier layers for GaN-HEMT structures

    International Nuclear Information System (INIS)

    Kirste, Lutz; Lim, Taek; Aidam, Rolf; Mueller, Stefan; Waltereit, Patrick; Ambacher, Oliver

    2010-01-01

    A high-resolution X-ray diffraction and X-ray reflectivity study of the structural properties of AlInN/GaN and AlGaInN/GaN high electron mobility transistor structures deposited by molecular beam epitaxy on metal organic chemical vapor deposition GaN/Al 2 O 3 and GaN/SiC templates is presented. A new AlN/GaN/AlN triple-interlayer is implemented to improve the interface properties between barrier layer and GaN buffer for a higher mobility of the polarization induced two-dimensional electron gas. Layer properties and structural parameters like concentration, interface quality, layer thickness, strain and crystalline perfection are analyzed. Best structural properties are achieved for an AlGaInN layer with AlN/GaN/AlN interlayer deposited on a GaN/4H-SiC (00.1) template. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Effect of Modified Atmosphere Packaging on Aril Physico-chemical and Microbial Properties of Two Pomegranate Cultivars (Punica granatum L. Grown in Iran

    Directory of Open Access Journals (Sweden)

    Sedighe Tavasoli Talarposhti

    2016-10-01

    Full Text Available Background and Objectives: Edible parts of pomegranate fruits are a rich source of bioactive compounds. The present research examines the effect of modified atmosphere packaging on the fruit physico-chemical and microbial properties of two commercial pomegranate cultivars grown in Iran. Materials and Methods: The arils were packaged and stored under four different atmospheres. All of the packaged samples were stored at 4 °C for 15 days. Results: The results revealed an increase in total acidity of all treatments. The highest total soluble solid (TSS was observed in ‘Yousef-Khani’­ stored in 10% O2 + 15% CO2, while ‘Malas-e-Saveh’ treated with 20% O2 + 5% CO2 showed the highest degree of TSS. The mean value of a* in ‘Malas-e-Saveh’ arils packed with normal and (15% O2 + 10% CO2 + 75% N2 atmosphere increased significantly. The L* showed a decrease in ‘Yousef-Khani’­. Total phenolic compounds gradually increased during storage. After storage, decreases in total anthocyanin contents ranged from 12 to 30% for ‘Yousef-Khani’­. The overall antioxidant activity of arils in ‘Yousef-Khani’ showed a 6-15% increase during storage. However, a reverse effect was observed for ‘Malas-e-Saveh’. The lowest microbial counts were recorded under the atmosphere containing 10 and 15% CO2. Conclusions: Packaging of ‘Malas-e-Saveh’ arils in 15% O2 + 10% CO2 and ‘Yousef-Khani’ in 15% O2 + 10% CO2 or 10% O2 + 15% CO2 is recommended to extend the shelf-life of ready-to-eat arils. Keywords: Pomegranate, Modified atmosphere, Phenolic compounds, Anthocyanin, Antioxidant activity

  10. Skin barrier composition

    International Nuclear Information System (INIS)

    Osburn, F.G.

    1985-01-01

    A skin barrier composition comprises a mixture of a copolymer resin of ethylene and vinyl acetate (EVA), and a water-insoluble dry tack-providing elastomer such as polyisobutylene. The composition after mixing and molding, is subjected to ionizing irradiation to form cross-linked polymer networks of the EVA. The compositions have exceptional properties for use as barrier sheets, rings, or strips in ostomy, wound drainage, and incontinence devices. (author)

  11. Skin barrier composition

    Energy Technology Data Exchange (ETDEWEB)

    Osburn, F G

    1985-06-12

    A skin barrier composition comprises a mixture of a copolymer resin of ethylene and vinyl acetate (EVA), and a water-insoluble dry tack-providing elastomer such as polyisobutylene. The composition after mixing and molding, is subjected to ionizing irradiation to form cross-linked polymer networks of the EVA. The compositions have exceptional properties for use as barrier sheets, rings, or strips in ostomy, wound drainage, and incontinence devices.

  12. Deep subsurface microbial processes

    Science.gov (United States)

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

    1995-01-01

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

  13. Microbial biosensors

    International Nuclear Information System (INIS)

    Le Yu; Chen, Wilfred; Mulchandani, Ashok

    2006-01-01

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

  14. Bacteria in the vaginal microbiome alter the innate immune response and barrier properties of the human vaginal epithelia in a species-specific manner.

    Science.gov (United States)

    Doerflinger, Sylvie Y; Throop, Andrea L; Herbst-Kralovetz, Melissa M

    2014-06-15

    Bacterial vaginosis increases the susceptibility to sexually transmitted infections and negatively affects women's reproductive health. To investigate host-vaginal microbiota interactions and the impact on immune barrier function, we colonized 3-dimensional (3-D) human vaginal epithelial cells with 2 predominant species of vaginal microbiota (Lactobacillus iners and Lactobacillus crispatus) or 2 prevalent bacteria associated with bacterial vaginosis (Atopobium vaginae and Prevotella bivia). Colonization of 3-D vaginal epithelial cell aggregates with vaginal microbiota was observed with direct attachment to host cell surface with no cytotoxicity. A. vaginae infection yielded increased expression membrane-associated mucins and evoked a robust proinflammatory, immune response in 3-D vaginal epithelial cells (ie, expression of CCL20, hBD-2, interleukin 1β, interleukin 6, interleukin 8, and tumor necrosis factor α) that can negatively affect barrier function. However, P. bivia and L. crispatus did not significantly upregulate pattern-recognition receptor-signaling, mucin expression, antimicrobial peptides/defensins, or proinflammatory cytokines in 3-D vaginal epithelial cell aggregates. Notably, L. iners induced pattern-recognition receptor-signaling activity, but no change was observed in mucin expression or secretion of interleukin 6 and interleukin 8. We identified unique species-specific immune signatures from vaginal epithelial cells elicited by colonization with commensal and bacterial vaginosis-associated bacteria. A. vaginae elicited a signature that is consistent with significant disruption of immune barrier properties, potentially resulting in enhanced susceptibility to sexually transmitted infections during bacterial vaginosis. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  15. Effects of reclaimed water irrigation and nitrogen fertilization on the chemical properties and microbial community of soil

    DEFF Research Database (Denmark)

    Guo, Wei; Andersen, Mathias Neumann; Qi, Xue-bin

    2017-01-01

    microbes and the chemical properties of the soil, which indicated that nitrate N (NO3−-N) and total phosphorus (TP) had significant impact on abundance of Verrucomicrobia and Gemmatimonadetes, meanwhile the pH and organic matter (OM) had impact on abundance of Firmicutes and Actinobacteria significantly...

  16. On electrical and interfacial properties of iron and platinum Schottky barrier diodes on (111) n-type Si0.65Ge0.35

    Science.gov (United States)

    Hamri, D.; Teffahi, A.; Djeghlouf, A.; Chalabi, D.; Saidane, A.

    2018-04-01

    Current-voltage (I-V), capacitance-voltage-frequency (C-V-f) and conductance-voltage-frequency (G/ω-V-f) characteristics of Molecular Beam Epitaxy (MBE)-deposited Fe/n-Si0.65Ge0.35 (FM1) and Pt/n-Si0.65Ge0.35(PM2) (111) orientated Schottky barrier diodes (SBDs) have been investigated at room-temperature. Barrier height (ΦB0), ideality factor (n) and series resistance (RS) were extracted. Dominant current conduction mechanisms were determined. They revealed that Poole-Frenkel-type conduction mechanism dominated reverse current. Differences in shunt resistance confirmed the difference found in leakage current. Under forward bias, quasi-ohmic conduction is found at low voltage regions and space charge-limited conduction (SCLC) at higher voltage regions for both SBDs. Density of interface states (NSS) indicated a difference in interface reactivity. Distribution profiles of series resistance (RS) with bias gives a peak in depletion region at low-frequencies that disappears with increasing frequencies. These results show that interface states density and series resistance of Schottky diodes are important parameters that strongly influence electrical properties of FM1 and PM2 structures.

  17. Engineered Barrier System - Assessment of the Corrosion Properties of Copper Canisters. Report from a Workshop. Synthesis and extended abstract

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, Peter (ed.) [Quintessa Ltd., Henley-on-Thames (GB)] (and others)

    2006-03-15

    A general impression from literature studies, presentations by workshop participants and the informal hearing with SKB is that there is in general a strong basis for the handling of copper corrosion in safety assessment. Work has been ongoing in the area for many decades and there appears to be a consensus on several key aspects of corrosion, such as the existence of a threshold potential for localised corrosion. This is of key importance for the assessment of corrosion under repository conditions. Localised corrosion has to be evaluated for the initial oxygenated phase. There is a need to demonstrate that the corrosion profile in reality will be similar to those of small scale experiments, i.e. roughening without real pitting. There is also a need to develop a better and more transparent basis for assessing how much oxygen can be available during the early oxygenated phase. Regarding stress corrosion cracking, there is a need for a consistent and possibly more detailed explanation either why it can be completely disregarded, or accounted for by probabilistic methods. Copper is normally assumed to be resistant to corrosion in oxygen free environments. However, this is not correct for the extremely long time period of one million years covered by SKB's safety assessment. Copper will react with sulphide by reduction of water. This reaction is the basis for SKB's performance assessment model for copper corrosion. The key aspect of this model is the availability of sulphide. SKB may need to address in more detail the availability of sulphide from the groundwater and the buffer bentonite and its speciation and solubility behaviour. However, the most sensitive assumption in SKB's modelling appears to be the assumption of zero microbial activity in the buffer throughout the assessment time scale of 10{sup 6} years. A detailed justification of this assumption is needed and possibly also 'what-if' calculations to illustrate consequences if this

  18. Engineered Barrier System - Assessment of the Corrosion Properties of Copper Canisters. Report from a Workshop. Synthesis and extended abstract

    International Nuclear Information System (INIS)

    Robinson, Peter

    2006-03-01

    A general impression from literature studies, presentations by workshop participants and the informal hearing with SKB is that there is in general a strong basis for the handling of copper corrosion in safety assessment. Work has been ongoing in the area for many decades and there appears to be a consensus on several key aspects of corrosion, such as the existence of a threshold potential for localised corrosion. This is of key importance for the assessment of corrosion under repository conditions. Localised corrosion has to be evaluated for the initial oxygenated phase. There is a need to demonstrate that the corrosion profile in reality will be similar to those of small scale experiments, i.e. roughening without real pitting. There is also a need to develop a better and more transparent basis for assessing how much oxygen can be available during the early oxygenated phase. Regarding stress corrosion cracking, there is a need for a consistent and possibly more detailed explanation either why it can be completely disregarded, or accounted for by probabilistic methods. Copper is normally assumed to be resistant to corrosion in oxygen free environments. However, this is not correct for the extremely long time period of one million years covered by SKB's safety assessment. Copper will react with sulphide by reduction of water. This reaction is the basis for SKB's performance assessment model for copper corrosion. The key aspect of this model is the availability of sulphide. SKB may need to address in more detail the availability of sulphide from the groundwater and the buffer bentonite and its speciation and solubility behaviour. However, the most sensitive assumption in SKB's modelling appears to be the assumption of zero microbial activity in the buffer throughout the assessment time scale of 10 6 years. A detailed justification of this assumption is needed and possibly also 'what-if' calculations to illustrate consequences if this assumption turns out not to be

  19. Film forming microbial biopolymers for commercial applications--a review.

    Science.gov (United States)

    Vijayendra, S V N; Shamala, T R

    2014-12-01

    Microorganisms synthesize intracellular, structural and extracellular polymers also referred to as biopolymers for their function and survival. These biopolymers play specific roles as energy reserve materials, protective agents, aid in cell functioning, the establishment of symbiosis, osmotic adaptation and support the microbial genera to function, adapt, multiply and survive efficiently under changing environmental conditions. Viscosifying, gelling and film forming properties of these have been exploited for specific significant applications in food and allied industries. Intensive research activities and recent achievements in relevant and important research fields of global interest regarding film forming microbial biopolymers is the subject of this review. Microbial polymers such as pullulan, kefiran, bacterial cellulose (BC), gellan and levan are placed under the category of exopolysaccharides (EPS) and have several other functional properties including film formation, which can be used for various applications in food and allied industries. In addition to EPS, innumerable bacterial genera are found to synthesis carbon energy reserves in their cells known as polyhydroxyalkanoates (PHAs), microbial polyesters, which can be extruded into films with excellent moisture and oxygen barrier properties. Blow moldable biopolymers like PHA along with polylactic acid (PLA) synthesized chemically in vitro using lactic acid (LA), which is produced by LA bacteria through fermentation, are projected as biodegradable polymers of the future for packaging applications. Designing and creating of new property based on requirements through controlled synthesis can lead to improvement in properties of existing polysaccharides and create novel biopolymers of great commercial interest and value for wider applications. Incorporation of antimicrobials such as bacteriocins or silver and copper nanoparticles can enhance the functionality of polymer films especially in food packaging

  20. Contrasting genomic properties of free-living and particle-attached microbial assemblages within a coastal ecosystem

    Directory of Open Access Journals (Sweden)

    Maria W Smith

    2013-05-01

    Full Text Available The Columbia River (CR is a powerful economic and environmental driver in the US Pacific Northwest. Microbial communities in the water column were analyzed from four diverse habitats: 1 an estuarine turbidity maximum (ETM; 2 a chlorophyll maximum of the river plume; 3 an upwelling-associated hypoxic zone; and 4 the deep ocean bottom. Three size fractions, 0.1-0.8, 0.8-3 and 3-200 μm were collected for each habitat in August 2007, and used for DNA isolation and 454 sequencing, resulting in 12 metagenomes of >5 million reads (>1.6 Gbp. To characterize the dominant microorganisms and metabolisms contributing to coastal biogeochemistry, we used predicted peptide and rRNA data. The 3- and 0.8-μm metagenomes, representing particulate fractions, were taxonomically diverse across habitats. The 3-μm size fractions contained a high abundance of eukaryota with diatoms dominating the hypoxic water and plume, while cryptophytes were more abundant in the ETM. The 0.1-μm metagenomes represented mainly free-living bacteria and archaea. The most abundant archaeal hits were observed in the deep ocean and hypoxic water (19% of prokaryotic peptides in the 0.1-μm metagenomes, and were homologous to Nitrosopumilus maritimus (ammonia-oxidizing Thaumarchaeota. Bacteria dominated metagenomes of all samples. In the euphotic zone (estuary, plume and hypoxic ocean, the most abundant bacterial taxa (≥40 % of prokaryotic peptides represented aerobic photoheterotrophs. In contrast, the low-oxygen, deep water metagenome was enriched with sequences for strict and facultative anaerobes. Interestingly, many of the same anaerobic bacterial families were enriched in the 3-μm size fraction of the ETM (2-10X more abundant relative to the 0.1-μm metagenome, indicating possible formation of anoxic microniches within particles. Results from this study provide a metagenome perspective on ecosystem-scale metabolism in an upwelling-influenced river-dominated coastal margin.

  1. Improved Prediction of Blood-Brain Barrier Permeability Through Machine Learning with Combined Use of Molecular Property-Based Descriptors and Fingerprints.

    Science.gov (United States)

    Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

    2018-03-21

    Blood-brain barrier (BBB) permeability of a compound determines whether the compound can effectively enter the brain. It is an essential property which must be accounted for in drug discovery with a target in the brain. Several computational methods have been used to predict the BBB permeability. In particular, support vector machine (SVM), which is a kernel-based machine learning method, has been used popularly in this field. For SVM training and prediction, the compounds are characterized by molecular descriptors. Some SVM models were based on the use of molecular property-based descriptors (including 1D, 2D, and 3D descriptors) or fragment-based descriptors (known as the fingerprints of a molecule). The selection of descriptors is critical for the performance of a SVM model. In this study, we aimed to develop a generally applicable new SVM model by combining all of the features of the molecular property-based descriptors and fingerprints to improve the accuracy for the BBB permeability prediction. The results indicate that our SVM model has improved accuracy compared to the currently available models of the BBB permeability prediction.

  2. Effect of the addition order and amylose content on mechanical, barrier and structural properties of films made with starch and montmorillonite.

    Science.gov (United States)

    Romero-Bastida, C A; Bello-Pérez, L A; Velazquez, G; Alvarez-Ramirez, J

    2015-01-01

    This study considered the effect of amylose content (30% and 70%), montmorillonite (MMT) fraction (5 and 15%) and preparation method on mechanical and barrier properties of starch/clay nanocomposites prepared by casting. In Method 1, (30% w/w) glycerol was incorporated before starch gelatinization and MMT addition, while in Method 2 after gelatinization and MMT addition. Nanocomposites with higher amount of MMT showed the highest tensile strength and Young's modulus for both preparation methods. Method 1 favored nanocomposite properties of films with less amylose content, meanwhile Method 2 favored nanocomposites properties with higher amylose content. Water vapor permeability did not decrease significantly in starch films with different amylose content with the two different preparation methods. X-ray diffraction of the starch films indicated intercalated structures. Higher melting temperature (Tm) was found for nanocomposites with Method 2, indicating more ordered structures. Films with 70% amylose content have higher Tm than films with 30% amylose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Appearance of a conductive carbonaceous coating in a CO2 dielectric barrier discharge and its influence on the electrical properties and the conversion efficiency

    International Nuclear Information System (INIS)

    Belov, Igor; Paulussen, Sabine; Bogaerts, Annemie

    2016-01-01

    This work examines the properties of a dielectric barrier discharge (DBD) reactor, built for CO 2 decomposition, by means of electrical characterization, optical emission spectroscopy and gas chromatography. The discharge, formed in an electronegative gas (such as CO 2 , but also O 2 ), exhibits clearly different electrical characteristics, depending on the surface conductivity of the reactor walls. An asymmetric current waveform is observed in the metal-dielectric (MD) configuration, with sparse high-current pulses in the positive half-cycle (HC) and a more uniform regime in the negative HC. This indicates that the discharge is operating in two alternating regimes with rather different properties. At high CO 2 conversion regimes, a conductive coating is deposited on the dielectric. This so-called coated MD configuration yields a symmetric current waveform, with current peaks in both the positive and negative HCs. In a double-dielectric (DD) configuration, the current waveform is also symmetric, but without current peaks in both the positive and negative HC. Finally, the DD configuration with conductive coating on the inner surface of the outer dielectric, i.e. so-called coated DD, yields again an asymmetric current waveform, with current peaks in the negative HC. These different electrical characteristics are related to the presence of the conductive coating on the dielectric wall of the reactor and can be explained by an increase of the local barrier capacitance available for charge transfer. The different discharge regimes affect the CO 2 conversion, more specifically, the CO 2 conversion is lowest in the clean DD configuration. It is somewhat higher in the coated DD configuration, and still higher in the MD configuration. The clean and coated MD configuration, however, gave similar CO 2 conversion. These results indicate that the conductivity of the dielectric reactor walls can highly promote the development of the high-amplitude discharge current pulses and

  4. Impacts of pulsed electric field and heat treatment on quality and sensory properties and microbial inactivation of pomegranate juice.

    Science.gov (United States)

    Evrendilek, Gulsun A

    2017-12-01

    Synergistic effects of pulsed electric field+mild heat on quality properties of pomegranate juice were modeled using the best-fit multiple (non-) linear regression models with inactivation kinetics parameters of Escherichia coli O157:H7 and Staphylococcus aureus. No significant difference was detected between the control and the treated samples in terms of pH; °Brix; total antioxidant capacity; total monomeric anthocyanin content; total ascorbic acid concentration; and the sensory properties of flavor, taste, aftertaste, and overall acceptance ( p > 0.05). An exposure of 65.3 J and 40 ℃ caused an increase on conductivity; titratable acidity; L*, a*, and b* values; and a decrease of browning index, total phenolic content, total antioxidant capacity, total monomeric anthocyanin content, total ascorbic acid concentration, and in the sensory properties of color and sourness in pomegranate juice. The goodness-of-fit for the best-fit multiple (non-) linear regression models in descending order belonged to E. coli O157:H7 (92.98%), S. aureus (84.06%), color a* (83.9%), titratable acidity (81.3%), color L* (78.5%), color b* (78.3%), conductivity (74.8%), total phenolic content (74.1%), and total ascorbic acid concentration (64.74%), respectively. D e and z e values for E. coli O157:H7 and S. aureus ranged from 105.64 to 1093.25 and from 79.18 to 1057.73 µs with 27.39 and 30.80 J, consequently.

  5. Biosynthesis of fluorescent CdS nanocrystals with semiconductor properties: Comparison of microbial and plant production systems.

    Science.gov (United States)

    Al-Shalabi, Zahwa; Doran, Pauline M

    2016-04-10

    This study investigated fission yeast (Schizosaccharomyces pombe) and hairy roots of tomato (Solanum lycopersicum) as in vitro production vehicles for biological synthesis of CdS quantum dots. Cd added during the mid-growth phase of the cultures was detoxified within the biomass into inorganic sulphide-containing complexes with the quantum confinement properties of semiconductor nanocrystals. Significant differences were found between the two host systems in terms of nanoparticle production kinetics, yield and quality. The much slower growth rate of hairy roots compared with yeast is a disadvantage for commercial scaled-up production. Nanoparticle extraction from the biomass was less effective for the roots: 19% of the Cd present in the hairy roots was recovered after extraction compared with 34% for the yeast. The overall yield of CdS quantum dots was also lower for the roots: relative to the amount of Cd taken up into the biomass, 8.5% was recovered in yeast gel filtration fractions exhibiting quantum dot properties whereas the result for hairy roots was only 0.99%. Yeast-produced CdS crystallites were somewhat smaller with diameters of approximately 2-6 nm compared with those of 4-10nm obtained from the roots. The average ratio of inorganic sulphide to Cd for the purified and size-fractionated particles was 0.44 for the yeast and 1.6 for the hairy roots. Despite the limitations associated with hairy roots in terms of culture kinetics and product yield, this system produced CdS nanoparticles with enhanced photostability and 3.7-13-fold higher fluorescence quantum efficiency compared with those generated by yeast. This work demonstrates that the choice of cellular host can have a significant effect on nanoparticle functional properties as well as on the bioprocessing aspects of biological quantum dot synthesis. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Investigating the mechanical and barrier properties to oxygen and fuel of high density polyethylene–graphene nanoplatelet composites

    Energy Technology Data Exchange (ETDEWEB)

    Honaker, K., E-mail: honakers@egr.msu.edu; Vautard, F.; Drzal, L.T.

    2017-02-15

    Highlights: • Melt mixing used to investigate high density polyethylene and graphene nanoplatelet composite. • Addition of graphene nanoplatelets resulted in a stiffer polymer matrix. • Presence of graphene nanoplatelets causes a decrease in oxygen and fuel permeation. - Abstract: Graphene nanoplatelets (GnP) of different sizes were investigated for their ability to modify high density polyethylene (HDPE) for potential fuel system applications, focusing on compounding via melt mixing in a twin-screw extruder. Mechanical properties, crystallinity of the polymer, and permeation to oxygen and fuel were assessed as a function of GnP concentration. The surface of GnP acted as a nucleation site for the generation of HDPE crystallites, increasing the crystallinity. The flexural properties were improved, clearly influenced by platelet size and quality of dispersion. A sharp, 46% decrease of the impact resistance was observed, even at low GnP concentration (0.2 wt.%). With a 15 wt.% GnP-M-15 (platelets with a 15 μm diameter), a 73% reduction in oxygen permeation was observed and a 74% reduction in fuel vapor transmission. This correlation was similar throughout the GnP concentration range. The smaller diameter platelets had a lesser effect on the properties.

  7. Effect of Suspension Plasma-Sprayed YSZ Columnar Microstructure and Bond Coat Surface Preparation on Thermal Barrier Coating Properties

    Science.gov (United States)

    Bernard, Benjamin; Quet, Aurélie; Bianchi, Luc; Schick, Vincent; Joulia, Aurélien; Malié, André; Rémy, Benjamin

    2017-08-01

    Suspension plasma spraying (SPS) is identified as promising for the enhancement of thermal barrier coating (TBC) systems used in gas turbines. Particularly, the emerging columnar microstructure enabled by the SPS process is likely to bring about an interesting TBC lifetime. At the same time, the SPS process opens the way to a decrease in thermal conductivity, one of the main issues for the next generation of gas turbines, compared to the state-of-the-art deposition technique, so-called electron beam physical vapor deposition (EB-PVD). In this paper, yttria-stabilized zirconia (YSZ) coatings presenting columnar structures, performed using both SPS and EB-PVD processes, were studied. Depending on the columnar microstructure readily adaptable in the SPS process, low thermal conductivities can be obtained. At 1100 °C, a decrease from 1.3 W m-1 K-1 for EB-PVD YSZ coatings to about 0.7 W m-1 K-1 for SPS coatings was shown. The higher content of porosity in the case of SPS coatings increases the thermal resistance through the thickness and decreases thermal conductivity. The lifetime of SPS YSZ coatings was studied by isothermal cyclic tests, showing equivalent or even higher performances compared to EB-PVD ones. Tests were performed using classical bond coats used for EB-PVD TBC coatings. Thermal cyclic fatigue performance of the best SPS coating reached 1000 cycles to failure on AM1 substrates with a β-(Ni,Pt)Al bond coat. Tests were also performed on AM1 substrates with a Pt-diffused γ-Ni/γ'-Ni3Al bond coat for which more than 2000 cycles to failure were observed for columnar SPS YSZ coatings. The high thermal compliance offered by both the columnar structure and the porosity allowed the reaching of a high lifetime, promising for a TBC application.

  8. Chemical Profiling and Evaluation of Antioxidant and Anti-Microbial Properties of Selected Commercial Essential Oils: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Ângelo Luís

    2017-06-01

    Full Text Available Background: The last decades have seen an increased awareness by the scientific community of the extent of resistance to conventional antibiotics, particularly with respect to the emerging multidrug-resistant pathogenic microbes. Additionally, natural antioxidants have received significant attention among food professionals and consumers because of their assumed safety and potential therapeutic value. The aim of this work was to assess the antioxidant activities of eight selected commercial essential oils (EOs, together with the evaluation of their antibacterial and anti-quorum sensing properties. Methods: The chemical profiling of the EOs was performed using gas chromatography-mass spectrometry (GC-MS analysis. The antioxidant properties of the EOs were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH free radical scavenging assay and by β-carotene bleaching test. Disc diffusion assays were employed to evaluate the anti-bacterial and anti-quorum sensing activities of the EOs. Results: It was observed that EOs from three Eucalyptus species are rich in eucalyptol. Generally, linalool is abundant in EOs from four Lavandula species. The oil of Cymbopogon citratus is the one with the best capacity to scavenge the DPPH free radicals and presented great antibacterial activity. Conclusions: The geographical origins of the plant species are determinant factors in the EO composition and in the corresponding biological activities.

  9. N-acyl homoserine lactone-degrading microbial enrichment cultures isolated from Penaeus vannamei shrimp gut and their probiotic properties in Brachionus plicatilis cultures.

    Science.gov (United States)

    Tinh, Nguyen Thi Ngoc; Asanka Gunasekara, R A Y S; Boon, Nico; Dierckens, Kristof; Sorgeloos, Patrick; Bossier, Peter

    2007-10-01

    Three bacterial enrichment cultures (ECs) were isolated from the digestive tract of Pacific white shrimp Penaeus vannamei, by growing the shrimp microbial communities in a mixture of N-acyl homoserine lactone (AHL) molecules. The ECs, characterized by denaturing gradient gel electrophoresis analysis and subsequent rRNA sequencing, degraded AHL molecules in the degradation assays. Apparently, the resting cells of the ECs also degraded one of the three types of quorum-sensing signal molecules produced by Vibrio harveyi in vitro [i.e. harveyi autoinducer 1 (HAI-1)]. The most efficient AHL-degrading ECs, EC5, was tested in Brachionus experiments. EC5 degraded the V. harveyi HAI-1 autoinducer in vivo, neutralizing the negative effect of V. harveyi autoinducer 2 (AI-2) mutant, in which only the HAI-1- and CAI-1-mediated components of the quorum-sensing system are functional on the growth of Brachionus. This suggests that EC5 interferes with HAI-1-regulated metabolism in V. harveyi. These AHL-degrading ECs need to be tested in other aquatic systems for their probiotic properties, preferably in combination with specific AI-2-degrading bacteria.

  10. Spatial variation in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican in soil and its relationship with chemical and microbial properties

    International Nuclear Information System (INIS)

    Bending, Gary D.; Lincoln, Suzanne D.; Edmondson, Rodney N.

    2006-01-01

    The extent of within field variability in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican, and the role of intrinsic soil factors and technical errors in contributing to the variability, was investigated in sites on sandy-loam and clay-loam. At each site, 40 topsoil samples were taken from a 160x60 m area, and pesticides applied in the laboratory. Time to 25% dissipation (DT25) ranged between 13 and 61 weeks for diflufenican, 5.6 and 17.2 weeks for azoxystrobin, and 0.3 and 12.5 weeks for isoproturon. Variability in DT25 was higher in the sandy-loam in which there was also greatest variability in soil chemical and microbial properties. Technical error associated with pesticide extraction, analysis and lack of model fit during derivation of DT25 accounted for between 5.3 and 25.8% of the variability for isoproturon and azoxystrobin, but could account for almost all the variability for diflufenican. Azoxystrobin DT25, sorption and pH were significantly correlated. - Spatial variation determines risk assessment for pesticides in soil

  11. Probiotic and technological properties of Lactobacillus spp. strains from the human stomach in the search for potential candidates against gastric microbial dysbiosis.

    Science.gov (United States)

    Delgado, Susana; Leite, Analy M O; Ruas-Madiedo, Patricia; Mayo, Baltasar

    2014-01-01

    This work characterizes a set of lactobacilli strains isolated from the stomach of healthy humans that might serve as probiotic cultures. Ten different strains were recognized by rep-PCR and PFGE fingerprinting among 19 isolates from gastric biopsies and stomach juice samples. These strains belonged to five species, Lactobacillus gasseri (3), Lactobacillus reuteri (2), Lactobacillus vaginalis (2), Lactobacillus fermentum (2) and Lactobacillus casei (1). All ten strains were subjected to a series of in vitro tests to assess their functional and technological properties, including acid resistance, bile tolerance, adhesion to epithelial gastric cells, production of antimicrobial compounds, inhibition of Helicobacter pylori, antioxidative activity, antibiotic resistance, carbohydrate fermentation, glycosidic activities, and ability to grow in milk. As expected, given their origin, all strains showed good resistance to low pH (3.0), with small reductions in counts after 90 min exposition to this pH. Species- and strain-specific differences were detected in terms of the production of antimicrobials, antagonistic effects toward H. pylori, antioxidative activity and adhesion to gastric epithelial cells. None of the strains showed atypical resistance to a series of 16 antibiotics of clinical and veterinary importance. Two L. reuteri strains were deemed as the most appropriate candidates to be used as potential probiotics against microbial gastric disorders; these showed good survival under gastrointestinal conditions reproduced in vitro, along with strong anti-Helicobacter and antioxidative activities. The two L. reuteri strains further displayed appropriated technological traits for their inclusion as adjunct functional cultures in fermented dairy products.

  12. MAPLE fabricated magnetite@eugenol and (3-hidroxybutyric acid-co-3-hidroxyvaleric acid)–polyvinyl alcohol microspheres coated surfaces with anti-microbial properties

    Energy Technology Data Exchange (ETDEWEB)

    Grumezescu, Valentina [Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Magurele, Bucharest (Romania); Department of Science and Engineering of Oxidic Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1–7 Polizu Street, 011061 Bucharest (Romania); Holban, Alina Maria [Microbiology Immunology Department, Faculty of Biology, University of Bucharest, 1–3 Portocalelor Lane, Sector 5, 77206Bucharest (Romania); Iordache, Florin [Institute of Cellular Biology and Pathology of Romanian Academy, “Nicolae Simionescu”, Department of Fetal and Adult Stem Cell Therapy, 8, B.P. Hasdeu, Bucharest 050568 (Romania); Socol, Gabriel [Lasers Department, National Institute for Lasers, Plasma and Radiation Physics, P.O. Box MG-36, Magurele, Bucharest (Romania); Mogoşanu, George Dan [Department of Pharmacognosy and Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 PetruRareş Street, 200349 Craiova (Romania); Grumezescu, Alexandru Mihai, E-mail: grumezescu@yahoo.com [Department of Science and Engineering of Oxidic Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1–7 Polizu Street, 011061 Bucharest (Romania); Ficai, Anton; Vasile, Bogdan Ştefan [Department of Science and Engineering of Oxidic Materials and Nanomaterials, Faculty of Applied Chemistry and Materials Science, University Politehnica of Bucharest, 1–7 Polizu Street, 011061 Bucharest (Romania); Truşcă, Roxana [S.C. Metav-CD S.A., 31Rosetti Str., 020015 Bucharest (Romania); Chifiriuc, Mariana Carmen [Microbiology Immunology Department, Faculty of Biology, University of Bucharest, 1–3 Portocalelor Lane, Sector 5, 77206Bucharest (Romania); others, and

    2014-07-01

    This study reports the biological applications of a newly fabricated water dispersible nanostructure, based on magnetite (Fe{sub 3}O{sub 4}) and eugenol (E), prepared in a well-shaped spherical form by precipitation method. The presence of Fe{sub 3}O{sub 4}@E nanoparticles has been confirmed by transmission electron microscopy (TEM). Nanoparticles have been embedded into poly(3-hidroxybutyric acid-co-3-hidroxyvaleric acid)–polyvinyl alcohol (P(3HB-3HV)–PVA) microspheres by oil-in-water emulsion technique. Functionalized P(3HB-3HV)–PVA–Fe{sub 3}O{sub 4}@E microspheres coatings have been fabricated by matrix assisted pulsed laser evaporation (MAPLE). The coatings have been characterized by infrared microscopy (IRM) and scanning electron microscopy (SEM). In vitro biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa was assessed by the viable cell counts technique. Nanomaterial biocompatibility has been investigated by analyzing the phenotypic changes of cultured eukaryotic cells. Besides their excellent anti-adherence and anti-biofilm properties, the MAPLE coatings have the advantages of using bioactive natural compounds, which are less toxic and easily biodegradable than current antibiotics. This approach could be used as a successful alternative or adjuvant method to control and prevent microbial biofilms associated infections.

  13. A Systematic Study of Separators in Air-Breathing Flat-Plate Microbial Fuel Cells—Part 1: Structure, Properties, and Performance Correlations

    Directory of Open Access Journals (Sweden)

    Sona Kazemi

    2016-01-01

    Full Text Available Passive air-breathing microbial fuel cells (MFCs are a promising technology for energy recovery from wastewater and their performance is highly dependent on characteristics of the separator that isolates the anaerobic anode from the air-breathing cathode. The goal of the present work is to systematically study the separator characteristics and its effect on the performance of passive air-breathing flat-plate MFCs (FPMFCs. This was performed through characterization of structure, properties, and performance correlations of eight separators in Part 1 of this work. Eight commercial separators were characterized, in non-inoculated and inoculated setups, and were examined in passive air-breathing FPMFCs with different electrode spacing. The results showed a decrease in the peak power density as the oxygen and ethanol mass transfer coefficients in the separators increased, due to the increase of mixed potentials especially at smaller electrode spacing. Increasing the electrode spacing was therefore desirable for the application of diaphragms. The highest peak power density was measured using Nafion®117 with minimal electrode spacing, whereas using Nafion®117 or Celgard® with larger electrode spacing resulted in similar peak powers. Part 2 of this work focuses on numerical modelling of the FPMFCs based on mixed potential theory, implementing the experimental data from Part 1.

  14. Spatial variation in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican in soil and its relationship with chemical and microbial properties.

    Science.gov (United States)

    Bending, Gary D; Lincoln, Suzanne D; Edmondson, Rodney N

    2006-01-01

    The extent of within field variability in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican, and the role of intrinsic soil factors and technical errors in contributing to the variability, was investigated in sites on sandy-loam and clay-loam. At each site, 40 topsoil samples were taken from a 160 x 60 m area, and pesticides applied in the laboratory. Time to 25% dissipation (DT25) ranged between 13 and 61 weeks for diflufenican, 5.6 and 17.2 weeks for azoxystrobin, and 0.3 and 12.5 weeks for isoproturon. Variability in DT25 was higher in the sandy-loam in which there was also greatest variability in soil chemical and microbial properties. Technical error associated with pesticide extraction, analysis and lack of model fit during derivation of DT25 accounted for between 5.3 and 25.8% of the variability for isoproturon and azoxystrobin, but could account for almost all the variability for diflufenican. Azoxystrobin DT25, sorption and pH were significantly correlated.

  15. Spatial variation in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican in soil and its relationship with chemical and microbial properties

    Energy Technology Data Exchange (ETDEWEB)

    Bending, Gary D. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom)]. E-mail: gary.bending@warwick.ac.uk; Lincoln, Suzanne D. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom); Edmondson, Rodney N. [Warwick HRI, University of Warwick, Wellesbourne, Warwick CV35 9EF (United Kingdom)

    2006-01-15

    The extent of within field variability in the degradation rate of the pesticides isoproturon, azoxystrobin and diflufenican, and the role of intrinsic soil factors and technical errors in contributing to the variability, was investigated in sites on sandy-loam and clay-loam. At each site, 40 topsoil samples were taken from a 160x60 m area, and pesticides applied in the laboratory. Time to 25% dissipation (DT25) ranged between 13 and 61 weeks for diflufenican, 5.6 and 17.2 weeks for azoxystrobin, and 0.3 and 12.5 weeks for isoproturon. Variability in DT25 was higher in the sandy-loam in which there was also greatest variability in soil chemical and microbial properties. Technical error associated with pesticide extraction, analysis and lack of model fit during derivation of DT25 accounted for between 5.3 and 25.8% of the variability for isoproturon and azoxystrobin, but could account for almost all the variability for diflufenican. Azoxystrobin DT25, sorption and pH were significantly correlated. - Spatial variation determines risk assessment for pesticides in soil.

  16. MAPLE fabricated magnetite@eugenol and (3-hidroxybutyric acid-co-3-hidroxyvaleric acid)–polyvinyl alcohol microspheres coated surfaces with anti-microbial properties

    International Nuclear Information System (INIS)

    Grumezescu, Valentina; Holban, Alina Maria; Iordache, Florin; Socol, Gabriel; Mogoşanu, George Dan; Grumezescu, Alexandru Mihai; Ficai, Anton; Vasile, Bogdan Ştefan; Truşcă, Roxana; Chifiriuc, Mariana Carmen

    2014-01-01

    This study reports the biological applications of a newly fabricated water dispersible nanostructure, based on magnetite (Fe 3 O 4 ) and eugenol (E), prepared in a well-shaped spherical form by precipitation method. The presence of Fe 3 O 4 @E nanoparticles has been confirmed by transmission electron microscopy (TEM). Nanoparticles have been embedded into poly(3-hidroxybutyric acid-co-3-hidroxyvaleric acid)–polyvinyl alcohol (P(3HB-3HV)–PVA) microspheres by oil-in-water emulsion technique. Functionalized P(3HB-3HV)–PVA–Fe 3 O 4 @E microspheres coatings have been fabricated by matrix assisted pulsed laser evaporation (MAPLE). The coatings have been characterized by infrared microscopy (IRM) and scanning electron microscopy (SEM). In vitro biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa was assessed by the viable cell counts technique. Nanomaterial biocompatibility has been investigated by analyzing the phenotypic changes of cultured eukaryotic cells. Besides their excellent anti-adherence and anti-biofilm properties, the MAPLE coatings have the advantages of using bioactive natural compounds, which are less toxic and easily biodegradable than current antibiotics. This approach could be used as a successful alternative or adjuvant method to control and prevent microbial biofilms associated infections.

  17. Nanocomposite biofilms obtained from Whitemouth croaker (Micropogonias furnieri) protein isolate and Montmorillonite: evaluation of the physical, mechanical and barrier properties

    International Nuclear Information System (INIS)

    Cortez-Vega, William Renzo; Bagatini, Daniela Cardozo; Souza, Juliana Tais Andreghetto de; Prentice, Carlos

    2013-01-01

    The objective of this study was to evaluate the properties of nanocomposite biofilms based on Whitemouth croaker (Micropogonias furnieri) protein isolate with organophilic clays. Initially the croaker protein isolate (CPI) was obtained using the pH shifting process from by-products of croaker industrialization. A Box and Behnken experimental design was used to develop the films, with three levels of CPI (2, 3.5 and 5 g.100 g -1 solution), montmorillonite MMT clay (0.3, 0.5 and 0.7 g.100 g -1 solution) and glycerol (25, 30 and 35 g.100g -1 CPI). The polymeric films were produced by the 'casting technique'. The tensile strength values ranged from 7.2 to 10.7 MPa and the elongation values from 39.6 to 45.8 %. The water vapor permeability (WVP) values ranged from 3.2 to 5.5 (g.mm.m -2 .d -1 ) and the CPI had an average protein content of 97.87 % protein (d. b.). It was concluded that the nanocomposite films produced from CPI with MMT were promising from the standpoint of their mechanical properties, visual appearance and easy handling, as well as for their low water vapor permeability and low water solubility. With respect to their mechanical properties, the concentrations of CPI and MMT were the main factors influencing the development of the nanocomposite films. The results obtained from the experimental design indicated that 3.5 g of CPI.100 g -1 solution, 0.5 g of MMT.100 g -1 solution and 30 g of glycerol.100 g -1 CPI would be the ideal parameters for the development of nanocomposite films by 'casting'. (author)

  18. Improving molten fluoride salt and Xe135 barrier property of nuclear graphite by phenolic resin impregnation process

    Science.gov (United States)

    He, Zhao; Lian, Pengfei; Song, Yan; Liu, Zhanjun; Song, Jinliang; Zhang, Junpeng; Feng, Jing; Yan, Xi; Guo, Quangui

    2018-02-01

    A densification process has been conducted on isostatic graphite (IG-110, TOYO TANSO CO., Ltd., Japan) by impregnating phenolic resin to get the densified isostatic graphite (D-IG-110) with pore diameter of nearly 11 nm specifically for molten salt reactor application. The microstructure, mechanical, thermophysical and other properties of graphite were systematically investigated and compared before and after the densification process. The molten fluoride salt and Xe135 penetration in the graphite were evaluated in a high-pressure reactor and a vacuum device, respectively. Results indicated that D-IG-110 exhibited improved properties including infiltration resistance to molten fluoride salt and Xe135 as compared to IG-110 due to its low porosity of 2.8%, the average pore diameter of 11 nm and even smaller open pores on the surface of the graphite. The fluoride salt infiltration amount of IG-110 was 13.5 wt% under 1.5 atm and tended to be saturated under 3 atm with the fluoride salt occupation of 14.8 wt%. As to the D-IG-110, no salts could be detected even up to 10 atm attempted loading. The helium diffusion coefficient of D-IG-110 was 6.92 × 10-8 cm2/s, significantly less than 1.21 × 10-2 cm2/s of IG-110. If these as-produced properties for impregnated D-IG-110 could be retained during MSR operation, the material could prove effective at inhibiting molten fluoride salt and Xe135 inventories in the graphite.

  19. Study of scenario 'mistake in determination of adsorbing properties of radionuclides on the materials of engineering barriers and host rock'

    International Nuclear Information System (INIS)

    Amosov, P.V.; Novozhilova, N.V.

    2008-01-01

    During investigations within the framework of this ASE of a storage facility, conceptual and mathematical models remained the same, as in SNE. Basic provisions of models, a solution 'tool' for diffusion equation taking into account radioactive decay and the chosen boundary conditions are presented in paper. The 79 Se isotope is chosen as basic analyzed radionuclide within the framework of the accepted ASE. The selection of this isotope can be substantiated by the following reasons: 1) Migration parameters of this radionuclide, in particular, the distribution coefficient of 79 Se isotope has specific enough values. For example, in granitoid formations (according to different research groups from Sweden, Finland, Switzerland during rather a small time range of experiments carrying out) the values of distribution coefficient vary within 20 times and thus its numerical value is small enough (0.0005 - 0.01 m 3 /kg). At the same time, the situation is reverse with cement materials: from references accessible to us only in one the value of this parameter is cited. 2) Performing calculations for the full list of radio-nuclides (in the SNE there were 8 of them) will require considerable labor expenditures and computer facilities resources: much processor time and much memory on a hard disk to store information. Since, when considering the selected ASE of facility there are accepted 4 areas of materials (the source, concrete, bentonite, the host rock) generally, it means practically a fourfold increase of all specified expenses in comparison with similar expenses for a SNE of facility. The main conclusions are: There are considered possible variants of error, which consequence is the 79 Se isotope transition in the category of a non-sorbing one in respective barrier of the near field that can conservatively lead to an increase of the facility hazard. If there is an error in selection of sorption parameters of 79 Se isotope in the host rock an increase in pollution of the

  20. Mechanical properties of EB-PVD ZrO{sub 2} thermal barrier coatings; Mechanische Eigenschaften von EB-PVD ZrO{sub 2} Waermedaemmschichten

    Energy Technology Data Exchange (ETDEWEB)

    Held, Carolin

    2014-08-29

    In this work, the elastic properties of thermal barrier coatings which were produced by electron-beam enhanced physical vapour deposition were investigated, as well as the dependency of the properties on the sample microstructure, the thermal treatment and the test method. For this purpose, not only commercial coatings were characterized, but also special sample material was used which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 C, 1100 C and 1200 C and then tested in a specially developed miniaturized bend test and by dynamic mechanical analysis. The sample material was tested by nanoindentation in order to measure the Young's modulus on a local scale, and the porosity of the samples was determined by microstructure analysis and porosimetry. The decrease of porosity could be connected with sintering and subsequent stiffening of the material. The test results are dependent on the tested volume. A small test volume leads to larger measured Young's moduli, while a large test volume yields lower values. The test volume also has an influence on the increase of stiffness during thermal exposure. With a small tested volume, a quicker increase of the Young's modulus was registered, which could be associated to the sintering of local structures.

  1. Mechanical properties of EB-PVD ZrO{sub 2} thermal barrier coatings; Mechanische Eigenschaften von EB-PVD ZrO{sub 2} Waermedaemmschichten

    Energy Technology Data Exchange (ETDEWEB)

    Held, Carolin

    2014-08-29

    In this work, the elastic properties of thermal barrier coatings which were produced by electron-beam enhanced physical vapour deposition were investigated, as well as the dependency of the properties on the sample microstructure, the thermal treatment and the test method. For this purpose, not only commercial coatings were characterized, but also special sample material was used which consists of a 1 mm thick layer of EB-PVD TBC. This material was isothermally heat treated for different times at 950 C, 1100 C and 1200 C and then tested in a specially developed miniaturized bend test and by dynamic mechanical analysis. The sample material was tested by nanoindentation in order to measure the Young's modulus on a local scale, and the porosity of the samples was determined by microstructure analysis and porosimetry. The decrease of porosity could be connected with sintering and subsequent stiffening of the material. The test results are dependent on the tested volume. A small test volume leads to larger measured Young's moduli, while a large test volume yields lower values. The test volume also has an influence on the increase of stiffness during thermal exposure. With a small tested volume, a quicker increase of the Young's modulus was registered, which could be associated to the sintering of local structures.

  2. Surface modification of electrospun PVA/chitosan nanofibers by dielectric barrier discharge plasma at atmospheric pressure and studies of their mechanical properties and biocompatibility.

    Science.gov (United States)

    Das, Punamshree; Ojah, Namita; Kandimalla, Raghuram; Mohan, Kiranjyoti; Gogoi, Dolly; Dolui, Swapan Kumar; Choudhury, Arup Jyoti

    2018-03-22

    In this paper, surface of electrospun PVA/Cs nanofibers is modified using dielectric barrier discharge (DBD) plasma and the relationship between the observed mechanical properties and biocompatibility of the nanofibers and plasma-induced surface properties is discussed. Plasma treatment of electrospun PVA/Cs nanofibers is carried out with both inert (argon, Ar) and reactive (oxygen, O 2 ) gases at atmospheric pressure. Incorporation of oxygen-containing polar functional groups on the surface of Ar-plasma treated (PVA/Cs/Ar) and O 2 -plasma treated (PVA/Cs/O 2 ) nanofibers and increase in surface roughness contribute to the improvement of surface wettability and the decrease of contact angle with water of the nanofibers. Both PVA/Cs/Ar and PVA/Cs/O 2 nanofibers show high tensile strength (11.6-15.6%) and Young's modulus (33.8-37.3%) as compared to the untreated one. Experimental results show that in terms of haemolytic activity the PVA/Cs/Ar and PVA/Cs/O 2 nanofibers do not cause structural changes of blood cells and meet the biocompatibility requirements for blood-contacting polymeric materials. MTT cell viability results further reveals improvement in biocompatibility of PVA/Cs nanofibers after Ar and O 2 plasma treatment. The results suggest that DBD plasma treated electrospun PVA/Cs nanofibers have the potential to be used as wound dressing and scaffolds for tissue engineering. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. TNAP and EHD1 are over-expressed in bovine brain capillary endothelial cells after the re-induction of blood-brain barrier properties.

    Directory of Open Access Journals (Sweden)

    Barbara Deracinois

    Full Text Available Although the physiological properties of the blood-brain barrier (BBB are relatively well known, the phenotype of the component brain capillary endothelial cells (BCECs has yet to be described in detail. Likewise, the molecular mechanisms that govern the establishment and maintenance of the BBB are largely unknown. Proteomics can be used to assess quantitative changes in protein levels and identify proteins involved in the molecular pathways responsible for cellular differentiation. Using the well-established in vitro BBB model developed in our laboratory, we performed a differential nano-LC MALDI-TOF/TOF-MS study of Triton X-100-soluble protein species from bovine BCECs displaying either limited BBB functions or BBB functions re-induced by glial cells. Due to the heterogeneity of the crude extract, we increased identification yields by applying a repeatable, reproducible fractionation process based on the proteins' relative hydrophobicity. We present proteomic and biochemical evidence to show that tissue non-specific alkaline phosphatase (TNAP and Eps15 homology domain-containing protein 1(EDH1 are over-expressed by bovine BCECs after the re-induction of BBB properties. We discuss the impact of these findings on current knowledge of endothelial and BBB permeability.

  4. Effect of Plasticizer Type and Concentration on Tensile, Thermal and Barrier Properties of Biodegradable Films Based on Sugar Palm (Arenga pinnata Starch

    Directory of Open Access Journals (Sweden)

    Muhammed L. Sanyang

    2015-06-01

    Full Text Available The use of starch based films as a potential alternative choice to petroleum derived plastics is imperative for environmental waste management. This study presents a new biopolymer (sugar palm starch for the preparation of biodegradable packaging films using a solution casting technique. The effect of different plasticizer types (glycerol (G, sorbitol (S and glycerol-sorbitol (GS combination with varying concentrations (0, 15, 30 and 45, w/w% on the tensile, thermal and barrier properties of sugar palm starch (SPS films was evaluated. Regardless of plasticizer types, the tensile strength of plasticized SPS films decreased, whereas their elongation at break (E% increased as the plasticizer concentrations were raised. However, the E% for G and GS-plasticized films significantly decreased at a higher plasticizer concentration (45% w/w due to the anti-plasticization effect of plasticizers. Change in plasticizer concentration showed an insignificant effect on the thermal properties of S-plasticized films. The glass transition temperature of SPS films slightly decreased as the plasticizer concentration increased from 15% to 45%. The plasticized films exhibited increased water vapor permeability values from 4.855 × 10−10 to 8.70 × 10−10 g·m−1·s−1·Pa−1, irrespective of plasticizer types. Overall, the current study manifested that plasticized sugar palm starch can be regarded as a promising biopolymer for biodegradable films.

  5. Effects of indigenous yeasts on physicochemical and microbial properties of Korean soy sauce prepared by low-salt fermentation.

    Science.gov (United States)

    Song, Young-Ran; Jeong, Do-Youn; Baik, Sang-Ho

    2015-10-01

    This study deals with understanding the effects of salt reduction on both the physicochemical and microbiological properties of soy sauce fermentation and also the application of indigenous yeast starters to compensate for undesirable changes occurring in salt-reduced processes. Fermentation was tested in situ at a Korean commercial soy sauce processing unit. Salt reduction resulted in higher acidity as well as lower pH and contents of residual sugar and ethanol. Moreover, undesired flavor characteristics, due to a lack of distinctive compounds, was observed. In addition, putrefactive Staphylococcus and Enterococcus spp. were present only during salt-reduced fermentation. To control these adverse effects, a single or mixed culture of two indigenous yeasts, Torulaspora delbrueckii and Pichia guilliermondii, producing high ethanol and 3-methyl-1-butanol, respectively, were tested. Overall, all types of yeast applications inhibited undesirable bacterial growth despite salt reduction. Of the starter cultures tested, the mixed culture resulted in a balance of more complex and richer flavors with an identical flavor profile pattern to that obtained from high salt soy sauce. Hence, this strategy using functional yeast cultures offers a technological option to manufacture salt-reduced soy sauce while preserving its typical sensory characteristics without affecting safety. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Microbial fermented tea - a potential source of natural food preservatives

    NARCIS (Netherlands)

    Mo, H.Z.; Yang Zhu, Yang; Chen, Z.M.

    2008-01-01

    Antimicrobial activities of microbial fermented tea are much less known than its health beneficial properties. These antimicrobial activities are generated in natural microbial fermentation process with tea leaves as substrates. The antimicrobial components produced during the fermentation process

  7. Structure and barrier properties of human embryonic stem cell-derived retinal pigment epithelial cells are affected by extracellular matrix protein coating.

    Science.gov (United States)

    Sorkio, Anni; Hongisto, Heidi; Kaarniranta, Kai; Uusitalo, Hannu; Juuti-Uusitalo, Kati; Skottman, Heli

    2014-02-01

    Extracellular matrix (ECM) interactions play a vital role in cell morphology, migration, proliferation, and differentiation of cells. We investigated the role of ECM proteins on the structure and function of human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells during their differentiation and maturation from hESCs into RPE cells in adherent differentiation cultures on several human ECM proteins found in native human Bruch's membrane, namely, collagen I, collagen IV, laminin, fibronectin, and vitronectin, as well as on commercial substrates of xeno-free CELLstart™ and Matrigel™. Cell pigmentation, expression of RPE-specific proteins, fine structure, as well as the production of basal lamina by hESC-RPE on different protein coatings were evaluated after 140 days of differentiation. The integrity of hESC-RPE epithelium and barrier properties on different coatings were investigated by measuring transepithelial resistance. All coatings supported the differentiation of hESC-RPE cells as demonstrated by early onset of cell pigmentation and further maturation to RPE monolayers after enrichment. Mature RPE phenotype was verified by RPE-specific gene and protein expression, correct epithelial polarization, and phagocytic activity. Significant differences were found in the degree of RPE cell pigmentation and tightness of epithelial barrier between different coatings. Further, the thickness of self-assembled basal lamina and secretion of the key ECM proteins found in the basement membrane of the native RPE varied between hESC-RPE cultured on compared protein coatings. In conclusion, this study shows that the cell culture substrate has a major effect on the structure and basal lamina production during the differentiation and maturation of hESC-RPE potentially influencing the success of cell integrations and survival after cell transplantation.

  8. Ultraviolet A photosensitivity profile of dexchlorpheniramine maleate and promethazine-based creams: Anti-inflammatory, antihistaminic, and skin barrier protection properties.

    Science.gov (United States)

    Facchini, Gustavo; Eberlin, Samara; Clerici, Stefano Piatto; Alves Pinheiro, Ana Lucia Tabarini; Costa, Adilson

    2017-12-01

    Unwanted side effects such as dryness, hypersensitivity, and cutaneous photosensitivity are challenge for adherence and therapeutical success for patients using treatments for inflammatory and allergic skin response. In this study, we compared the effects of two dermatological formulations, which are used in inflammatory and/or allergic skin conditions: dexchlorpheniramine maleate (DCP; 10 mg/g) and promethazine (PTZ; 20 mg/g). We evaluated both formulations for phototoxicity potential, skin irritation, anti-inflammatory and antihistaminic abilities, and skin barrier repair in vitro and ex vivo using the standard OECD test guideline n° 432, the ECVAM protocol n° 78, and cultured skin explants from a healthy patient. Ultraviolet A was chosen as exogenous agent to induce allergic and inflammatory response. Both PTZ and DCP promoted increases in interleukin-1 (IL-1) synthesis in response to ultraviolet A (UVA) radiation compared to control. However, the increase observed with PTZ was significantly greater than the DCP, indicating that the latter has a lower irritant potential. DCP also demonstrated a protective effect on UVA-induced leukotriene B4 and nuclear factor kappa B (NF-κB) synthesis. Conversely, PTZ demonstrates more robust UVA antihistaminic activity. Likewise, PTZ promoted a significantly greater increase in the production of involucrin and keratin 14, both associated with protective skin barrier property. In conclusion, these data suggest possible diverging UVA response mechanisms of DCP and PTZ, which gives greater insight into the contrasting photosensitizing potential between DCP and PTZ observed in the patients. © 2017 Wiley Periodicals, Inc.

  9. KEFIRS MANUFACTURED FROM CAMEL (CAMELUS DRAMEDARIUS MILK AND COW MILK: COMPARISON OF SOME CHEMICAL AND MICROBIAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    G. Kavas

    2015-09-01

    Full Text Available This study examined the production possibilities of kefir from fresh camel milk fermented with grain. The findings were then compared with kefir manufactured from cow’s milk. Cow’s milk was fermented with 2.5% grains. The 1% (v/w glucose enriched camel’s milk was fermented with 10% grains and left in an incubator at 25°C. Physical-chemical and sensorial analyses of the kefir sampleswere measured on day one (18 hours of storage and microbiological analyses were measured on days one, three and five. Some physical-chemical parameters were found to be higherin camel milk and its kefir than in cow milk and its kefir, some were found to be close and some were found to be lower. Addition of 1% glucose and 10% grains to the camel milk affected the titrationacidity and viscosity of kefir to significant levels. The kefir produced from camel milk was perceived as sourer, whereas its other properties were found to be close to those of cow milk. Thecholesterol levels of camel milk and its kefir were detected to be higher when compared to those of cow milk and its kefir, but the cholesterol level decreased in both examples after the productionof kefir. In terms of the composition of fatty acids, it was determined that SFA and the small, medium chain fatty acids ratio was low in camel milk and its kefir, but MUFA and the long chainfatty acids ratio was high. PUFA ratio was high in camel milk but low in its kefir. In microbiological analysis, yeast levels increased in kefir samples with the Lactobacillus ssp. strains, and theincrease in the number of yeasts was higher than in the cow milk kefir. In kefir samples, Lactobacillus ssp. strains increased on day one and three of storage, but diminished after day three.

  10. Microbial glycoproteomics

    DEFF Research Database (Denmark)

    Halim, Adnan; Anonsen, Jan Haug

    2017-01-01

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

  11. Development of Innovating Materials for Distributing Mixtures of Hydrogen and Natural Gas. Study of the Barrier Properties and Durability of Polymer Pipes

    Directory of Open Access Journals (Sweden)

    Klopffer Marie-Hélène

    2015-02-01

    Full Text Available With the growing place taken by hydrogen, a question still remains about its delivery and transport from the production site to the end user by employing the existing extensive natural gas pipelines. Indeed, the key challenge is the significant H2 permeation through polymer infrastructures (PolyEthylene (PE pipes, components such as connecting parts. This high flow rate of H2 through PE has to be taken into account for safety and economic requirements. A 3-year project was launched, the aim of which was to develop and assess material solutions to cope with present problems for hydrogen gas distribution and to sustain higher pressure compared to classical high density polyethylene pipe. This project investigated pure hydrogen gas and mixtures with natural gas (20% of CH4 and 80% of H2 in pipelines with the aim to select engineering polymers which are more innovative than polyethylene and show outstanding properties, in terms of permeation, basic mechanical tests but also more specific characterizations such as long term ageing and behaviour. The adequate benches, equipments and scientific approach for materials testing had been developed and validated. In this context, the paper will focus on the evaluation of the barrier properties of 3 polymers (PE, PA11 and PAHM. Experiments were performed for pure H2 and CH4 and also in the presence of mixtures of hydrogen and natural gas in order to study the possible mixing effects of gases. It will report some round-robin tests that have been carried out. Secondly, by comparing data obtained on film, polymer membrane and on pipe section, the influence of the polymer processing will be studied. Innovative multilayers systems will be proposed and compared on the basis of the results obtained on monolayer systems. Finally, the evolution of the transport properties of the studied polymers with an ageing under representative service conditions will be discussed.

  12. What is microbial community ecology?

    Science.gov (United States)

    Konopka, Allan

    2009-11-01

    The activities of complex communities of microbes affect biogeochemical transformations in natural, managed and engineered ecosystems. Meaningfully defining what constitutes a community of interacting microbial populations is not trivial, but is important for rigorous progress in the field. Important elements of research in microbial community ecology include the analysis of functional pathways for nutrient resource and energy flows, mechanistic understanding of interactions between microbial populations and their environment, and the emergent properties of the complex community. Some emergent properties mirror those analyzed by community ecologists who study plants and animals: biological diversity, functional redundancy and system stability. However, because microbes possess mechanisms for the horizontal transfer of genetic information, the metagenome may also be considered as a community property.

  13. Application of 1D and 2D MFR reactor technology for the isolation of insecticidal and anti-microbial properties from pyrolysis bio-oils.

    Science.gov (United States)

    Hossain, Mohammad M; Scott, Ian M; Berruti, Franco; Briens, Cedric

    2016-12-01

    Valuable chemicals can be separated from agricultural residues by chemical or thermochemical processes. The application of pyrolysis has already been demonstrated as an efficient means to produce a liquid with a high concentration of desired product. The objective of this study was to apply an insect and microorganism bioassay-guided approach to separate and isolate pesticidal compounds from bio-oil produced through biomass pyrolysis. Tobacco leaf (Nicotianata bacum), tomato plant (Solanum lycopersicum), and spent coffee (Coffea arabica) grounds were pyrolyzed at 10°C/min from ambient to 565°C using the mechanically fluidized reactor (MFR). With one-dimensional (1D) MFR pyrolysis, the composition of the product vapors varied as the reactor temperature was raised allowing for the selection of the temperature range that corresponds to vapors with a high concentration of pesticidal properties. Further product separation was performed in a fractional condensation train, or 2D MFR pyrolysis, thus allowing for the separation of vapor components according to their condensation temperature. The 300-400°C tobacco and tomato bio-oil cuts from the 1D MFR showed the highest insecticidal and anti-microbial activity compared to the other bio-oil cuts. The 300-350 and 350-400°C bio-oil cuts produced by 2D MFR had the highest insecticidal activity when the bio-oil was collected from the 210°C condenser. The tobacco and tomato bio-oil had similar insecticidal activity (LC 50 of 2.1 and 2.2 mg/mL) when the bio-oil was collected in the 210°C condenser from the 300-350°C reactor temperature gases. The 2D MFR does concentrate the pesticidal products compared to the 1D MFR and thus can reduce the need for further separation steps such as solvent extraction.

  14. How ecosystems change following invasion by Robinia pseudoacacia: Insights from soil chemical properties and soil microbial, nematode, microarthropod and plant communities.

    Science.gov (United States)

    Lazzaro, Lorenzo; Mazza, Giuseppe; d'Errico, Giada; Fabiani, Arturo; Giuliani, Claudia; Inghilesi, Alberto F; Lagomarsino, Alessandra; Landi, Silvia; Lastrucci, Lorenzo; Pastorelli, Roberta; Roversi, Pio Federico; Torrini, Giulia; Tricarico, Elena; Foggi, Bruno

    2018-05-01

    Biological invasions are a global threat to biodiversity. Since the spread of invasive alien plants may have many impacts, an integrated approach, assessing effects across various ecosystem components, is needed for a correct understanding of the invasion process and its consequences. The nitrogen-fixing tree Robinia pseudoacacia (black locust) is a major invasive species worldwide and is used in forestry production. While its effects on plant communities and soils are well known, there have been few studies on soil fauna and microbes. We investigated the impacts of the tree on several ecosystem components, using a multi-trophic approach to combine evidence of soil chemical properties and soil microbial, nematode, microarthropod and plant communities. We sampled soil and vegetation in managed forests, comparing those dominated by black locust with native deciduous oak stands. We found qualitative and quantitative changes in all components analysed, such as the well-known soil nitrification and acidification in stands invaded by black locust. Bacterial richness was the only component favoured by the invasion. On the contrary, abundance and richness of microarthropods, richness of nematodes, and richness and diversity of plant communities decreased significantly in invaded stands. The invasion process caused a compositional shift in all studied biotic communities and in relationships between the different ecosystem components. We obtained clear insights into the effects of invasion of managed native forests by black locust. Our data confirms that the alien species transforms several ecosystem components, modifying the plant-soil community and affecting biodiversity at different levels. Correct management of this aggressive invader in temperate forests is urgently required. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Probiotic and technological properties of Lactobacillus spp. strains from the human stomach in the search for potential candidates against gastric microbial dysbiosis

    Directory of Open Access Journals (Sweden)

    Susana eDelgado

    2015-01-01

    Full Text Available This work characterizes a set of lactobacilli strains isolated from the stomach of healthy humans that might serve as probiotic cultures. Ten different strains were recognized by rep-PCR and PFGE fingerprinting among 19 isolates from gastric biopsies and stomach juice samples. These strains belonged to five species, Lactobacillus gasseri (3, Lactobacillus reuteri (2, Lactobacillus vaginalis (2, Lactobacillus fermentum (2 and Lactobacillus casei (1. All ten strains were subjected to a series of in vitro tests to assess their functional and technological properties, including acid resistance, bile tolerance, adhesion to epithelial gastric cells, production of antimicrobial compounds, inhibition of Helicobacter pylori, antioxidative activity, antibiotic resistance, carbohydrate fermentation, glycosidic activities, and ability to grow in milk. As expected, given their origin, all strains showed good resistance to low pH (3.0, with small reductions in counts after 90 min exposition to this pH. Species- and strain-specific differences were detected in terms of the production of antimicrobials, antagonistic effects towards H. pylori, antioxidative activity and adhesion to gastric epithelial cells. None of the strains showed atypical resistance to a series of 16 antibiotics of clinical and veterinary importance. Two L. reuteri strains were deemed as the most appropriate candidates to be used as potential probiotics against microbial gastric disorders; these showed good survival under gastrointestinal conditions reproduced in vitro, along with strong anti-Helicobacter and antioxidative activities. The two L. reuteri strains further displayed appropriated technological traits for their inclusion as adjunct functional cultures in fermented dairy products.

  16. Coupled modelling (transport-reaction) of the fluid-clay interactions and their feed back on the physical properties of the bentonite engineered clay barrier system; Modelisation couplee (transport - reaction) des interactions fluides - argiles et de leurs effets en retour sur les proprietes physiques de barrieres ouvragees en bentonite

    Energy Technology Data Exchange (ETDEWEB)

    Marty, N

    2006-11-15

    The originality of this work is to process feed back effects of mineralogical and chemical modifications of clays, in storage conditions, on their physical properties and therefore on their transport characteristics (porosity, molecular diffusion, permeability). These feed back effects are modelled using the KIRMAT code (Kinetic of Reaction and MAss Transfer) developed from the kinetic code KINDIS by adding the effect of water renewal in the mineral-solution reactive cells. KIRMAT resolves mass balance equations associated with mass transport together with the geochemical reactions in a 1D approach. After 100 000 years of simulated interaction at 100 C, with the fluid of the Callovo-Oxfordian geological level (COX) and with iron provided by the steel overpack corrosion, the montmorillonite of the clay barrier is only partially transformed (into illite, chlorite, saponite...). Only outer parts of the modelled profile seem to be significantly affected by smectite dissolution processes, mainly at the interface with the geological environment. The modifications of physical properties show a closure of the porosity at the boundaries of the barrier, by creating a decrease of mass transport by molecular diffusion, essentially at the interface with the iron. Permeability laws applied to this system show a decrease of the hydraulic conductivity correlated with the porosity evolution. Near the COX, the swelling pressure of the clays from the barrier decreases. In the major part of the modelled profile, the engineered clay barrier system seems to keep its initial physical properties (porosity, molecular diffusion, permeability, swelling pressure) and functionalities. (author)

  17. Microbial xanthophylls.

    Science.gov (United States)

    Bhosale, Prakash; Bernstein, Paul S

    2005-09-01

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

  18. Comparative Study of Chemical, Mechanical, Thermal, and Barrier Properties of Poly(Lactic Acid Plasticized with Epoxidized Soybean Oil and Epoxidized Palm Oil

    Directory of Open Access Journals (Sweden)

    Yee Bond Tee

    2015-12-01

    Full Text Available To investigate epoxidized palm oil’s (EPO potential as plasticizer for poly(lactic acid (PLA, its plasticizing effect was compared with commercialized epoxidized soybean oil (ESO. The plasticizers were respectively melt-compounded into PLA at 3, 5, 10, and 15 wt.%. As it was aimed for the blends to be characterized towards packaging appropriate for food products, they were hot-pressed into ~0.3-mm sheets, which is the approximate thickness of clamshell packaging. Fourier transform infrared spectroscopy (FTIR confirmed the plasticizers’ compatibility with PLA. At similar loadings, EPO was superior in reinforcing elongation at break (EAB, thermal, and barrier properties of PLA. The ductility of PLA was notably improved to 50.0% with addition of 3 wt.% of EPO. From thermogravimetric analysis (TGA, PLA/EPO5 improved PLA’s thermal stability, while all PLA/ESO blends reported reduced thermal stability. From differential scanning calorimetry (DSC, the increase in crystallinity and the shifts in enthalpy of fusions in all plasticized blends denoted facilitation of PLA to form thermally stable α-form crystals. The addition of EPO enabled PLA to become highly impermeable to oxygen, which can extend its potential in packaging extensive range of oxygen sensitive food.

  19. Light Absorptive Properties of Articular Cartilage, ECM Molecules, Synovial Fluid, and Photoinitiators as Potential Barriers to Light-Initiated Polymer Scaffolding Procedures.

    Science.gov (United States)

    Finch, Anthony J; Benson, Jamie M; Donnelly, Patrick E; Torzilli, Peter A

    2017-06-01

    Objective Many in vivo procedures to repair chondral defects use ultraviolet (UV)-photoinitiated in situ polymerization within the cartilage matrix. Chemical species that absorb UV light might reduce the effectiveness of these procedures by acting as light absorption barriers. This study evaluated whether any of the individual native biochemical components in cartilage and synovial fluid interfered with the absorption of light by common scaffolding photosensitizers. Materials UV-visible spectroscopy was performed on each major component of cartilage in solution, on bovine synovial fluid, and on four photosensitizers, riboflavin, Irgacure 2959, quinine, and riboflavin-5'-phosphate. Molar extinction and absorption coefficients were calculated at wavelengths of maximum absorbance and 365 nm. Intact articular cartilage was also examined. Results The individual major biochemical components of cartilage, Irgacure 2959, and quinine did not exhibit a significant absorption at 365 nm. Riboflavin and riboflavin-5'-phosphate were more effectual light absorbers at 365 nm, compared with the individual native species. Intact cartilage absorbed a significantly greater amount of UV light in comparison with the native species. Conclusion Our results indicate that none of the individual native species in cartilage will interfere with the absorption of UV light at 365 nm by these commonly used photoinitiators. Intact cartilage slices exhibited significant light absorption at 365 nm, while also having distinct absorbance peaks at wavelengths less than 300 nm. Determining the UV absorptive properties of the biomolecules native to articular cartilage and synovial fluid will aid in optimizing scaffolding procedures to ensure sufficient scaffold polymerization at a minimum UV intensity.

  20. In silico modeling on ADME properties of natural products: Classification models for blood-brain barrier permeability, its application to traditional Chinese medicine and in vitro experimental validation.

    Science.gov (United States)

    Zhang, Xiuqing; Liu, Ting; Fan, Xiaohui; Ai, Ni

    2017-08-01

    In silico modeling of blood-brain barrier (BBB) permeability plays an important role in early discovery of central nervous system (CNS) drugs due to its high-throughput and cost-effectiveness. Natural products (NP) have demonstrated considerable therapeutic efficacy against several CNS diseases. However, BBB permeation property of NP is scarcely evaluated both experimentally and computationally. It is well accepted that significant difference in chemical spaces exists between NP and synthetic drugs, which calls into doubt on suitability of available synthetic chemical based BBB permeability models for the evaluation of NP. Herein poor discriminative performance on BBB permeability of NP are first confirmed using internal constructed and previously published drug-derived computational models, which warrants the need for NP-oriented modeling. Then a quantitative structure-property relationship (QSPR) study on a NP dataset was carried out using four different machine learning methods including support vector machine, random forest, Naïve Bayes and probabilistic neural network with 67 selected features. The final consensus model was obtained with approximate 90% overall accuracy for the cross-validation study, which is further taken to predict passive BBB permeability of a large dataset consisting of over 10,000 compounds from traditional Chinese medicine (TCM). For 32 selected TCM molecules, their predicted BBB permeability were evaluated by in vitro parallel artificial membrane permeability assay and overall accuracy for in vitro experimental validation is around 81%. Interestingly, our in silico model successfully predicted different BBB permeation potentials of parent molecules and their known in vivo metabolites. Finally, we found that the lipophilicity, the number of hydrogen bonds and molecular polarity were important molecular determinants for BBB permeability of NP. Our results suggest that the consensus model proposed in current work is a reliable tool for

  1. Effects of the strain relaxation of an AlGaN barrier layer induced by various cap layers on the transport properties in AlGaN/GaN heterostructures

    International Nuclear Information System (INIS)

    Liu Zi-Yang; Zhang Jin-Cheng; Duan Huan-Tao; Xue Jun-Shuai; Lin Zhi-Yu; Ma Jun-Cai; Xue Xiao-Yong; Hao Yue

    2011-01-01

    The strain relaxation of an AlGaN barrier layer may be influenced by a thin cap layer above, and affects the transport properties of AlGaN/GaN heterostructures. Compared with the slight strain relaxation found in AlGaN barrier layer without cap layer, it is found that a thin cap layer can induce considerable changes of strain state in the AlGaN barrier layer. The degree of relaxation of the AlGaN layer significantly influences the transport properties of the two-dimensional electron gas (2DEG) in AlGaN/GaN heterostructures. It is observed that electron mobility decreases with the increasing degree of relaxation of the AlGaN barrier, which is believed to be the main cause of the deterioration of crystalline quality and morphology on the AlGaN/GaN interface. On the other hand, both GaN and AlN cap layers lead to a decrease in 2DEG density. The reduction of 2DEG caused by the GaN cap layer may be attributed to the additional negative polarization charges formed at the interface between GaN and AlGaN, while the reduction of the piezoelectric effect in the AlGaN layer results in the decrease of 2DEG density in the case of AlN cap layer. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  2. Degradation of microbial polyesters.

    Science.gov (United States)

    Tokiwa, Yutaka; Calabia, Buenaventurada P

    2004-08-01

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

  3. Trends and barriers to lateral gene transfer in prokaryotes.

    Science.gov (United States)

    Popa, Ovidiu; Dagan, Tal

    2011-10-01

    Gene acquisition by lateral gene transfer (LGT) is an important mechanism for natural variation among prokaryotes. Laboratory experiments show that protein-coding genes can be laterally transferred extremely fast among microbial cells, inherited to most of their descendants, and adapt to a new regulatory regime within a short time. Recent advance in the phylogenetic analysis of microbial genomes using networks approach reveals a substantial impact of LGT during microbial genome evolution. Phylogenomic networks of LGT among prokaryotes reconstructed from completely sequenced genomes uncover barriers to LGT in multiple levels. Here we discuss the kinds of barriers to gene acquisition in nature including physical barriers for gene transfer between cells, genomic barriers for the integration of acquired DNA, and functional barriers for the acquisition of new genes. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Effects of gamma ray and electron beam irradiation on reduction of microbial load and antioxidant properties of Chum-Hed-Thet (Cassia alata (L.) Roxb.)

    Science.gov (United States)

    Prakhongsil, P.; Pewlong, W.; Sajjabut, S.; Chookaew, S.

    2017-06-01

    Considering the growing demands of herbal medicines, Cassia alata (L.) Roxb. has been reported to have various phytochemical activities. It has also been called in Thai as Chum-Hed-Thet. In this study, C. alata (L.) Roxb. powder were exposed to gamma and electron beam irradiation at doses of 0, 5, 10, 15 and 20 kGy. At the dose of 10 kGy, both of gamma and electron beam irradiation were sufficient in reducing microbial load of irradiated samples as specified in Thai pharmacopoeia (2005). These include the total aerobic microbial count of bacteria of 0.05). Therefore, both of radiation by gamma ray or electron beam at 10 kGy was sufficient in elimination of microbial flora and did not significantly affected the total phenolic content and antioxidant activities of C. alata (L.) Roxb.

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

    Energy Technology Data Exchange (ETDEWEB)

    Frouz, J.; Kristufek, V.; Liveckova, M.; van Loo, D.; Jacobs, P.; Van Hoorebeke, L. [Charles University of Prague, Prague (Czech Republic). Inst. of Environmental Studies

    2011-01-15

    Soil aggregates between 2 and 5 mm from 35- and 45-year-old unreclaimed post-mining sites near Sokolov (Czech Republic) were divided into two groups: spherical and prismatic. X-ray tomography indicated that prismatic aggregates consisted of fragments of claystone bonded together by amorphous clay and roots while spherical aggregates consisted of a clay matrix and organic fragments of various sizes. Prismatic aggregates were presumed to be formed by plant roots and physical processes during weathering of Tertiary mudstone, while earthworms were presumed to contribute to the formation of spherical aggregates. The effects of drying and rewetting and glucose addition on microbial respiration, microbial biomass, and counts of bacteria in these aggregates were determined. Spherical aggregates contained a greater percentage of C and N and a higher C-to-N ratio than prismatic ones. The C content of the particulate organic matter was also higher in the spherical than in the prismatic aggregates. Although spherical aggregates had a higher microbial respiration and biomass, the growth of microbial biomass in spherical aggregates was negatively correlated with initial microbial biomass, indicating competition between bacteria. Specific respiration was negatively correlated with microbial biomass. Direct counts of bacteria were higher in spherical than in prismatic aggregates. Bacterial numbers were more stable in the center than in the surface layers of the aggregates. Transmission electron microscopy indicated that bacteria often occurred as individual cells in prismatic aggregates but as small clusters of cells in spherical aggregates. Ratios of colony forming units (cultivatable bacteria) to direct counts were higher in spherical than in prismatic aggregates. Spherical aggregates also contained faster growing bacteria.

  6. Microbial effects

    International Nuclear Information System (INIS)

    Sharpe, V.J.

    1985-10-01

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

  7. Barrier Systems

    NARCIS (Netherlands)

    Heteren, S. van

    2015-01-01

    Barrier-system dynamics are a function of antecedent topography and substrate lithology, Relative sea-level (RSL) changes, sediment availability and type, climate, vegetation type and cover, and various aero- and hydrodynamic processes during fair-weather conditions and extreme events. Global change

  8. MICROBIAL SURFACTANTS IN ENVIRONMENTAL TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    T. P. Pirog

    2015-08-01

    Full Text Available It was shown literature and own experimental data concerning the use of microbial surface active glycolipids (rhamno-, sophoro- and trehalose lipids and lipopeptides for water and soil purification from oil and other hydrocarbons, removing toxic heavy metals (Cu2+, Cd2+, Ni2+, Pb2+, degradation of complex pollution (oil and other hydrocarbons with heavy metals, and the role of microbial surfactants in phytoremediation processes. The factors that limit the use of microbial surfactants in environmental technologies are discussed. Thus, at certain concentrations biosurfactant can exhibit antimicrobial properties and inhibit microorganisms destructing xenobiotics. Microbial biodegradability of surfactants may also reduce the effectiveness of bioremediation. Development of effective technologies using microbial surfactants should include the following steps: monitoring of contaminated sites to determine the nature of pollution and analysis of the autochthonous microbiota; determining the mode of surfactant introduction (exogenous addition of stimulation of surfactant synthesis by autochthonous microbiota; establishing an optimal concentration of surfactant to prevent exhibition of antimicrobial properties and rapid biodegradation; research both in laboratory and field conditions.

  9. Shottky-barrier formation

    International Nuclear Information System (INIS)

    Guines, F.; Sanchez-Dehesa, J.; Flores, F.

    1983-01-01

    In this paper a realistic selfconsistent calculation of an abrupt metal-semiconductor junction is presented by means of a tight-binding approach. A specific Si-Ag junction has been considered, and the charge neutrality level as well as the barrier height have been determined in good agreement with experiments. For a generaljunction it is shown that the interface properties depend essentially on the characteristics of the first metal layer and its interaction with the semiconductor. (Author) [pt

  10. Microbial communities on glacier surfaces in Svalbard: the impact of physical and chemical properties on abundance and structure of cyanobacteria and algae

    Czech Academy of Sciences Publication Activity Database

    Stibal, Marek; Šabacká, Marie; Kaštovská, Klára

    2006-01-01

    Roč. 52, č. 4 (2006), s. 644-654 ISSN 0095-3628 R&D Projects: GA AV ČR KJB6005409 Institutional research plan: CEZ:AV0Z60050516 Keywords : Microbial community * Svalbard * glacier surface Subject RIV: EF - Botanics Impact factor: 2.332, year: 2006

  11. Development of soil microbial properties in topsoil layer during spontaneous succession in heaps after brown coal mining in relation to humus microstructure development

    Czech Academy of Sciences Publication Activity Database

    Frouz, Jan; Nováková, Alena

    2005-01-01

    Roč. 129, 1-2 (2005), s. 54-64 ISSN 0016-7061 R&D Projects: GA ČR(CZ) GA526/01/1055 Institutional research plan: CEZ:AV0Z60660521 Keywords : succession in heaps * microbial respiration * biomass Subject RIV: EH - Ecology, Behaviour Impact factor: 1.773, year: 2005

  12. Water barrier properties of starch-clay nanocomposite films Propriedades de barreira à água de filmes de nanocompósitos de amido e argila

    Directory of Open Access Journals (Sweden)

    Aníbal Marcelo Slavutsky

    2012-09-01

    Full Text Available The functional properties of corn starch based films were improved by incorporating nanoclay (Montmorillonite. Nanoclay was incorporated in the polymer matrix using two different methodologies and the films were formed by casting. The effect of film preparation methodology and of the nanoclay concentration on the physicochemical properties of the films was studied. Depending on film preparation method used, intercalated or exfoliated nanocomposite films were obtained. The FTIR spectra showed a strong interaction between the montmorillonite and the starch molecules. Opacity was dependent on the nanoclay dispersion method used. Water vapor solubility and permeability decreased with increasing montmorillonite content and were affected by the dispersion method. Water diffusion was only dependent on the nanoclay content due to the increase in tortuosity of the diffusion path, caused by the nanoparticles. The results showed that the incorporation of 5% of montmorillonite using an adequate dispersion method, improved the water resistance and barrier properties of corn starch based films. Nanoparticles reduced the damage caused to the properties of these hydrophilic films by the increase in moisture content.As propriedades funcionais de filmes à base de amido de milho foram melhoradas pela incorporação de nanoargila (montmorilonita. Nanoargila foi incorporada na matriz polimérica por meio de duas metodologias diferentes e os filmes foram produzidos por casting. Os efeitos da metodologia de preparação e da concentração de nanoargila nas propriedades físico-químicas dos filmes foram estudados. Conforme os métodos de elaboração, filmes intercalados e esfoliados de nanocompósitos foram obtidos. Os espectros FTIR mostraram uma forte interação entre a argila montmorilonita e as moléculas de amido. A opacidade foi dependente do método utilizado para a dispersão da nanoargila. A solubilidade e a permeabilidade ao vapor de água diminu

  13. Information barriers

    International Nuclear Information System (INIS)

    Fuller, J.L.; Wolford, J.

    2001-01-01

    Full text: An information barrier (IB) consists of procedures and technology that prevent the release of sensitive information during a joint inspection of a sensitive nuclear item, and provides confidence that the measurement system into which it has been integrated functions exactly as designed and constructed. Work in the U.S. on radiation detection system information barriers dates back at least to 1990, even though the terminology is more recent. In January 1999 the Joint DoD-DOE Information Barrier Working Group was formed in the United States to help coordinate technical efforts related to information barrier R and D. This paper presents an overview of the efforts of this group, by its Chairs, as well as recommendations for further information barrier R and D. Progress on the demonstration of monitoring systems containing IBs is also provided. From the U.S. perspective, the basic, top-level functional requirements for the information barrier portion of an integrated radiation signature-information barrier inspection system are twofold: The host must be assured that his classified information is protected from disclosure to the inspecting party; and The inspecting party must be confident that the integrated inspection system measures, processes, and presents the radiation-signature-based measurement conclusion in an accurate and reproducible manner. It is the position of the United States that in the absence of any agreement to share classified nuclear weapons design information in the conduct of an inspection regime, the requirement to protect host country classified warhead design information is paramount and admits no tradeoff versus the confidence provided to the inspecting party in the accuracy and reproducibility of the measurements. The U.S. has reached an internal consensus on several critical design elements that define a general standard for radiation signature information barrier design. These criteria have stood the test of time under intense

  14. Effects of inorganic and organic amendment on soil chemical properties, enzyme activities, microbial community and soil quality in yellow clayey soil.

    Directory of Open Access Journals (Sweden)

    Zhanjun Liu

    Full Text Available Understanding the effects of external organic and inorganic components on soil fertility and quality is essential for improving low-yielding soils. We conducted a field study over two consecutive rice growing seasons to investigate the effect of applying chemical fertilizer (NPK, NPK plus green manure (NPKG, NPK plus pig manure (NPKM, and NPK plus straw (NPKS on the soil nutrient status, enzyme activities involved in C, N, P, and S cycling, microbial community and rice yields of yellow clayey soil. Results showed that the fertilized treatments significantly improved rice yields over the first three experimental seasons. Compared with the NPK treatment, organic amendments produced more favorable effects on soil productivity. Notably, the NPKM treatment exhibited the highest levels of nutrient availability, microbial biomass carbon (MBC, activities of most enzymes and the microbial community. This resulted in the highest soil quality index (SQI and rice yield, indicating better soil fertility and quality. Significant differences in enzyme activities and the microbial community were observed among the treatments, and redundancy analysis showed that MBC and available N were the key determinants affecting the soil enzyme activities and microbial community. The SQI score of the non-fertilized control (0.72 was comparable to that of the NPK (0.77, NPKG (0.81 and NPKS (0.79 treatments but significantly lower compared with NPKM (0.85. The significant correlation between rice yield and SQI suggests that SQI can be a useful to quantify soil quality changes caused by different agricultural management practices. The results indicate that application of NPK plus pig manure is the preferred option to enhance SOC accumulation, improve soil fertility and quality, and increase rice yield in yellow clayey soil.

  15. Excreted/secreted Trichuris suis products reduce barrier function and suppress inflammatory cytokine production of intestinal epithelial cells

    DEFF Research Database (Denmark)

    Hiemstra, I. H.; Klaver, E. J.; Vrijland, K.

    2014-01-01

    The administration of helminths is considered a promising strategy for the treatment of autoimmune diseases due to their immunomodulatory properties. Currently, the application of the helminth Trichuris suis as a treatment for Crohn's disease is being studied in large multi-center clinical trials....... The intestinal epithelium forms an efficient barrier between the intestinal lumen containing the microbial flora and helminths, and dendritic cells (DCs) present in the lamina propria that determine the TH response. Here, we investigated how excreted/secreted (E/S) products of T. suis affect the barrier function...... of intestinal epithelial cells (IECs) in order to reach the DCs and modulate the immune response. We show that T. suis E/S products reduce the barrier function and the expression of the tight junction proteins EMP-1 and claudin-4 in IEC CMT93/69 monolayers in a glycan-dependent manner. This resulted...

  16. Floating barrier

    Energy Technology Data Exchange (ETDEWEB)

    1968-05-06

    This floating barrier consists of relatively long elements which can be connected to form a practically continuous assembly. Each element consists of an inflatable tube with an apron of certain height, made of impregnated fabric which is resistant to ocean water and also to hydrocarbons. Means for connecting one element to the following one, and means for attaching ballast to the apron are also provided.

  17. Characterization of the inhomogeneous barrier distribution in a Pt/(100)β-Ga2O3 Schottky diode via its temperature-dependent electrical properties

    Science.gov (United States)

    Jian, Guangzhong; He, Qiming; Mu, Wenxiang; Fu, Bo; Dong, Hang; Qin, Yuan; Zhang, Ying; Xue, Huiwen; Long, Shibing; Jia, Zhitai; Lv, Hangbing; Liu, Qi; Tao, Xutang; Liu, Ming

    2018-01-01

    β-Ga2O3 is an ultra-wide bandgap semiconductor with applications in power electronic devices. Revealing the transport characteristics of β-Ga2O3 devices at various temperatures is important for improving device performance and reliability. In this study, we fabricated a Pt/β-Ga2O3 Schottky barrier diode with good performance characteristics, such as a low ON-resistance, high forward current, and a large rectification ratio. Its temperature-dependent current-voltage and capacitance-voltage characteristics were measured at various temperatures. The characteristic diode parameters were derived using thermionic emission theory. The ideality factor n was found to decrease from 2.57 to 1.16 while the zero-bias barrier height Φb0 increased from 0.47 V to 1.00 V when the temperature was increased from 125 K to 350 K. This was explained by the Gaussian distribution of barrier height inhomogeneity. The mean barrier height Φ ¯ b0 = 1.27 V and zero-bias standard deviation σ0 = 0.13 V were obtained. A modified Richardson plot gave a Richardson constant A* of 36.02 A.cm-2.K-2, which is close to the theoretical value of 41.11 A.cm-2.K-2. The differences between the barrier heights determined using the capacitance-voltage and current-voltage curves were also in line with the Gaussian distribution of barrier height inhomogeneity.

  18. Numerical simulation of flood barriers

    Science.gov (United States)

    Srb, Pavel; Petrů, Michal; Kulhavý, Petr

    This paper deals with testing and numerical simulating of flood barriers. The Czech Republic has been hit by several very devastating floods in past years. These floods caused several dozens of causalities and property damage reached billions of Euros. The development of flood measures is very important, especially for the reduction the number of casualties and the amount of property damage. The aim of flood control measures is the detention of water outside populated areas and drainage of water from populated areas as soon as possible. For new flood barrier design it is very important to know its behaviour in case of a real flood. During the development of the barrier several standardized tests have to be carried out. Based on the results from these tests numerical simulation was compiled using Abaqus software and some analyses were carried out. Based on these numerical simulations it will be possible to predict the behaviour of barriers and thus improve their design.

  19. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke

    2016-01-01

    The skin is a strong and flexible organ with barrier properties essential for maintaining homeostasis and thereby human life. Characterizing this barrier is the ability to prevent some chemicals from crossing the barrier while allowing others, including medicinal products, to pass at varying rates......-through diffusion cells) as well as in vivo methods (microdialysis and microperfusion). Then follows a discussion with examples of how different characteristics of the skin (age, site and integrity) and of the penetrants (size, solubility, ionization, logPow and vehicles) affect the kinetics of percutaneous...

  20. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.

    2016-01-01

    positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking

  1. Comparison of three dielectric barrier discharges regarding their physical characteristics and influence on the adhesion properties on maple, high density fiberboards and wood plastic composite

    International Nuclear Information System (INIS)

    Peters, F; Wieneke, S; Ohms, G; Viöl, W; Hünnekens, B; Militz, H

    2017-01-01

    In this study, three different dielectric barrier discharges, based on the same setup and run with the same power supply, are characterized by emission spectroscopy with regards to the reduced electrical field strength, and the rotational, vibrational and electron temperature. To compare discharges common for the treatment on wood, a coplanar surface barrier discharge, a direct dielectric barrier discharge and a jet system/remote plasma are chosen. To minimize influences due to the setups or power, the discharges are realized with the same electrodes and power supply and normalized to the same power. To evaluate the efficiency of the different discharges and the influence on treated materials, the surface free energy is determined on a maple wood, high density fiberboard and wood plastic composite. The influence is measured depending on the treatment time, with the highest impact in the time of 5 s. (paper)

  2. Comparison of three dielectric barrier discharges regarding their physical characteristics and influence on the adhesion properties on maple, high density fiberboards and wood plastic composite

    Science.gov (United States)

    Peters, F.; Hünnekens, B.; Wieneke, S.; Militz, H.; Ohms, G.; Viöl, W.

    2017-11-01

    In this study, three different dielectric barrier discharges, based on the same setup and run with the same power supply, are characterized by emission spectroscopy with regards to the reduced electrical field strength, and the rotational, vibrational and electron temperature. To compare discharges common for the treatment on wood, a coplanar surface barrier discharge, a direct dielectric barrier discharge and a jet system/remote plasma are chosen. To minimize influences due to the setups or power, the discharges are realized with the same electrodes and power supply and normalized to the same power. To evaluate the efficiency of the different discharges and the influence on treated materials, the surface free energy is determined on a maple wood, high density fiberboard and wood plastic composite. The influence is measured depending on the treatment time, with the highest impact in the time of 5 s.

  3. Characterization of the inhomogeneous barrier distribution in a Pt/(100β-Ga2O3 Schottky diode via its temperature-dependent electrical properties

    Directory of Open Access Journals (Sweden)

    Guangzhong Jian

    2018-01-01

    Full Text Available β-Ga2O3 is an ultra-wide bandgap semiconductor with applications in power electronic devices. Revealing the transport characteristics of β-Ga2O3 devices at various temperatures is important for improving device performance and reliability. In this study, we fabricated a Pt/β-Ga2O3 Schottky barrier diode with good performance characteristics, such as a low ON-resistance, high forward current, and a large rectification ratio. Its temperature-dependent current–voltage and capacitance–voltage characteristics were measured at various temperatures. The characteristic diode parameters were derived using thermionic emission theory. The ideality factor n was found to decrease from 2.57 to 1.16 while the zero-bias barrier height Φb0 increased from 0.47 V to 1.00 V when the temperature was increased from 125 K to 350 K. This was explained by the Gaussian distribution of barrier height inhomogeneity. The mean barrier height Φ ¯ b0 = 1.27 V and zero-bias standard deviation σ0 = 0.13 V were obtained. A modified Richardson plot gave a Richardson constant A* of 36.02 A·cm−2·K−2, which is close to the theoretical value of 41.11 A·cm−2·K−2. The differences between the barrier heights determined using the capacitance–voltage and current–voltage curves were also in line with the Gaussian distribution of barrier height inhomogeneity.

  4. Microbial reduction of uranium using cellulosic substrates

    International Nuclear Information System (INIS)

    Thombre, M.S.; Thomson, B.M.; Barton, L.L.

    1996-01-01

    Previous work at the University of New Mexico and elsewhere has shown that sulfate-reducing bacteria are capable of reducing uranium from the soluble +6 oxidation state to the insoluble +4 oxidation state. This chemistry forms the basis of a proposed ground water remediation strategy in which microbial reduction would be used to immobilize soluble uranium. One such system would consist of a subsurface permeable barrier which would stimulate microbial growth resulting in the reduction of sulfate and nitrate and immobilization of metals while permitting the unhindered flow of ground water through it. This research investigated some of the engineering considerations associated with a microbial reducing barrier such as identifying an appropriate biological substrate, estimating the rate of substrate utilization, and identifying the final fate of the contaminants concentrated in the barrier matrix. The performance of batch reactors and column systems that treated simulated plume water was evaluated using cellulose, wheat straw, alfalfa hay, sawdust, and soluble starch as substrates. The concentrations of sulfate, nitrate, and U(VI) were monitored over time. Precipitates from each system were collected, and the precipitated U(IV) was determined to be crystalline UO 2(s) by x-ray diffraction. The results of this study support the proposed use of cellulosic substrates as candidate barrier materials

  5. Microbial biofilms: biosurfactants as antibiofilm agents.

    Science.gov (United States)

    Banat, Ibrahim M; De Rienzo, Mayri A Díaz; Quinn, Gerry A

    2014-12-01

    Current microbial inhibition strategies based on planktonic bacterial physiology have been known to have limited efficacy on the growth of biofilm communities. This problem can be exacerbated by the emergence of increasingly resistant clinical strains. All aspects of biofilm measurement, monitoring, dispersal, control, and inhibition are becoming issues of increasing importance. Biosurfactants have merited renewed interest in both clinical and hygienic sectors due to their potential to disperse microbial biofilms in addition to many other advantages. The dispersal properties of biosurfactants have been shown to rival those of conventional inhibitory agents against bacterial and yeast biofilms. This makes them suitable candidates for use in new generations of microbial dispersal agents and for use as adjuvants for existing microbial suppression or eradication strategies. In this review, we explore aspects of biofilm characteristics and examine the contribution of biologically derived surface-active agents (biosurfactants) to the disruption or inhibition of microbial biofilms.

  6. Analysis of Schottky Barrier Parameters and Current Transport Properties of V/p-Type GaN Schottky Junction at Low Temperatures

    Science.gov (United States)

    Asha, B.; Harsha, Cirandur Sri; Padma, R.; Rajagopal Reddy, V.

    2018-05-01

    The electrical characteristics of a V/p-GaN Schottky junction have been investigated by current-voltage (I-V) and capacitance-voltage (C-V) characteristics under the assumption of the thermionic emission (TE) theory in the temperature range of 120-280 K with steps of 40 K. The zero-bias barrier height (ΦB0), ideality factor (n), flat-band barrier height (ΦBF) and series resistance (R S) values were evaluated and were found to be strongly temperature dependent. The results revealed that the ΦB0 values increase, whereas n, ΦFB and R S values decrease, with increasing temperature. Using the conventional Richardson plot, the mean barrier height (0.39 eV) and Richardson constant (8.10 × 10-10 Acm-2 K-2) were attained. The barrier height inhomogeneities were demonstrated by assuming a Gaussian distribution function. The interface state density (N SS) values were found to decrease with increasing temperature. The reverse leakage current mechanism of the V/p-GaN Schottky junction was found to be governed by Poole-Frenkel emission at all temperatures.

  7. Gas barrier properties of nanocomposites based on in situ polymerized poly(n-butyl methacrylate) in the presence of surface modified montmorillonite

    Czech Academy of Sciences Publication Activity Database

    Herrera-Alonso, J. M.; Sedláková, Zdeňka; Marand, E.

    2010-01-01

    Roč. 349, 1-2 (2010), s. 251-257 ISSN 0376-7388 R&D Projects: GA AV ČR KAN100500651; GA MŠk ME09058 Institutional research plan: CEZ:AV0Z40500505 Keywords : barrier membranes * nanocomposites * montmorillonite Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.673, year: 2010

  8. Environmental properties and microbial communities in coastal waters of Barrow, Alaska from July 11, 2007 to January 14, 2009 (NODC Accession 0073540)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The data set consists of basic water column properties of the Beaufort Sea and the Chukchi Sea near Barrow, Alaska. The environmental properties include salinity,...

  9. Microbial micropatches within microbial hotspots

    Science.gov (United States)

    Smith, Renee J.; Tobe, Shanan S.; Paterson, James S.; Seymour, Justin R.; Oliver, Rod L.; Mitchell, James G.

    2018-01-01

    The spatial distributions of organism abundance and diversity are often heterogeneous. This includes the sub-centimetre distributions of microbes, which have ‘hotspots’ of high abundance, and ‘coldspots’ of low abundance. Previously we showed that 300 μl abundance hotspots, coldspots and background regions were distinct at all taxonomic levels. Here we build on these results by showing taxonomic micropatches within these 300 μl microscale hotspots, coldspots and background regions at the 1 μl scale. This heterogeneity among 1 μl subsamples was driven by heightened abundance of specific genera. The micropatches were most pronounced within hotspots. Micropatches were dominated by Pseudomonas, Bacteroides, Parasporobacterium and Lachnospiraceae incertae sedis, with Pseudomonas and Bacteroides being responsible for a shift in the most dominant genera in individual hotspot subsamples, representing up to 80.6% and 47.3% average abundance, respectively. The presence of these micropatches implies the ability these groups have to create, establish themselves in, or exploit heterogeneous microenvironments. These genera are often particle-associated, from which we infer that these micropatches are evidence for sub-millimetre aggregates and the aquatic polymer matrix. These findings support the emerging paradigm that the microscale distributions of planktonic microbes are numerically and taxonomically heterogeneous at scales of millimetres and less. We show that microscale microbial hotspots have internal structure within which specific local nutrient exchanges and cellular interactions might occur. PMID:29787564

  10. EVALUATION OF MICROBIAL SURVIVAL IN EXTRATERRESTRIAL ENVIRONMENTS

    Directory of Open Access Journals (Sweden)

    Betül BULUÇ

    2012-08-01

    Full Text Available In this paper, the space environments where microbial terrestrial life could form and evolve in, were evaluted with the base of the physical and chemical properties. In addition, Earthial microbial life formation conditions in the interstellar medium and the other planets are investigated and the survival of microorganisms in the space environments are questioned. As a result, considering the aspects of terrestrial microbial life, we suggest that the space environment and other planets could not be a habitat for Earthial microorganisms.

  11. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  12. Development of engineered barrier

    International Nuclear Information System (INIS)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja

    1999-03-01

    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and 316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  13. Effects of NH3 Flow Rate During AlGaN Barrier Layer Growth on the Material Properties of AlGaN/GaN HEMT Heterostructure

    Science.gov (United States)

    Lumbantoruan, Franky J.; Wong, Yuen-Yee; Huang, Wei-Ching; Yu, Hung-Wei; Chang, Edward-Yi

    2017-10-01

    NH3 flow rate during AlGaN barrier layer growth not only affects the growth efficiency and surface morphology as a result of parasitic reactions but also influences the concentration of carbon impurity in the AlGaN barrier. Carbon, which decomposes from metal precursors, plays a role in electron compensation for AlGaN/GaN HEMT. No 2-dimensional electron gas (2-DEG) was detected in the AlGaN/GaN structure if grown with 0.5 slm of NH3 due to the presence of higher carbon impurity (2.6 × 1019 cm-2). When the NH3 flow rate increased to 6.0 slm, the carbon impurity reduced to 2.10 × 1018 atom cm-3 and the 2 DEG electron density recovered to 9.57 × 1012 cm-2.

  14. Transparent Barrier Urethanes Based on Polyethylene Soft Segments

    National Research Council Canada - National Science Library

    Beck

    2000-01-01

    ...%. Flexible, transparent materials were produced. The mechanical and barrier properties of these urethanes were evaluated for comparison with the performance of traditional flexible barrier materials (e.g., butyl rubber...

  15. Effects of biochar blends on microbial community composition in two coastal plain soils

    Science.gov (United States)

    The amendment of soil with biochar has been demonstrated to have an effect not only on the soil physicochemical properties, but also on soil microbial community composition and activity. Previous reports have demonstrated significant impacts on soil microbial community structure....

  16. 11 Soil Microbial Biomass

    African Journals Online (AJOL)

    186–198. Insam H. (1990). Are the soil microbial biomass and basal respiration governed by the climatic regime? Soil. Biol. Biochem. 22: 525–532. Insam H. D. and Domsch K. H. (1989). Influence of microclimate on soil microbial biomass. Soil Biol. Biochem. 21: 211–21. Jenkinson D. S. (1988). Determination of microbial.

  17. Molecular microbial ecology manual

    NARCIS (Netherlands)

    Kowalchuk, G.A.; Bruijn, de F.J.; Head, I.M.; Akkermans, A.D.L.

    2004-01-01

    The field of microbial ecology has been revolutionized in the past two decades by the introduction of molecular methods into the toolbox of the microbial ecologist. This molecular arsenal has helped to unveil the enormity of microbial diversity across the breadth of the earth's ecosystems, and has

  18. Microbial Rechargeable Battery

    NARCIS (Netherlands)

    Molenaar, Sam D.; Mol, Annemerel R.; Sleutels, Tom H.J.A.; Heijne, Ter Annemiek; Buisman, Cees J.N.

    2016-01-01

    Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial

  19. Childhood microbial keratitis

    Directory of Open Access Journals (Sweden)

    Abdullah G Al Otaibi

    2012-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Shuang Zhao

    2016-04-01

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

  1. Studies about behavior of microbial degradation of organic compounds

    International Nuclear Information System (INIS)

    Ohtsuka, Makiko

    2003-02-01

    Some of TRU waste include organic compounds, thus these organic compounds might be nutrients for microbial growth at disposal site. This disposal system might be exposed to high alkali condition by cement compounds as engineering barrier material. In the former experimental studies, it has been supposed that microbial exist under pH = 12 and the microbial activity acclimated to high alkali condition are able to degrade asphalt under anaerobic condition. Microbes are called extremophile that exist in cruel habitat as high alkali or reductive condition. We know less information about the activity of extremophile, though any recent studies reveal them. In this study, the first investigation is metabolic pathway as microbial activity, the second is microbial degradation of aromatic compounds in anaerobic condition, and the third is microbial activity under high alkali. Microbial metabolic pathway consist of two systems that fulfill their function each other. One system is to generate energy for microbial activities and the other is to convert substances for syntheses of organisms' structure materials. As these systems are based on redox reaction between substances, it is made chart of the microbial activity region using pH, Eh, and depth as parameter, There is much report that microbe is able to degrade aromatic compounds under aerobic or molecular O 2 utilizing condition. For degradation of aromatic compounds in anaerobic condition, supplying electron acceptor is required. Co-metabolism and microbial consortia has important role, too. Alcalophile has individual transporting system depending Na + and acidic compounds contained in cell wall. Generating energy is key for survival and growth under high alkali condition. Co-metabolism and microbial consortia are effective for microbial degradation of aromatic compounds under high alkali and reductive condition, and utilizable electron acceptor and degradable organic compounds are required for keeping microbial activity and

  2. Sprache als Barriere (Language as a Barrier)

    Science.gov (United States)

    Mattheier, Klaus

    1974-01-01

    The concept of language barrier has its derivations in the fields of dialectology, sociology and psychology. In contemporary usage however, the concept has two meanings i.e. regional-cultural barrier and socio-cultural barrier. (Text is in German.) (DS)

  3. Effect of irradiation, active and modified atmosphere packaging, container oxygen barrier and storage conditions on the physicochemical and sensory properties of raw unpeeled almond kernels (Prunus dulcis).

    Science.gov (United States)

    Mexis, Stamatios F; Riganakos, Kyriakos A; Kontominas, Michael G

    2011-03-15

    The present study investigated the effect of irradiation, active and modified atmosphere packaging, and storage conditions on quality retention of raw, whole, unpeeled almonds. Almond kernels were packaged in barrier and high-barrier pouches, under N(2) or with an O(2) absorber and stored either under fluorescent lighting or in the dark at 20 °C for 12 months. Quality parameters monitored were peroxide value, hexanal content, colour, fatty acid composition and volatile compounds. Of the sensory attributes colour, texture, odour and taste were evaluated. Peroxide value and hexanal increased with dose of irradiation and storage time. Irradiation resulted in a decrease of polyunsaturated and monounsaturated fatty acids during storage with a parallel increase of saturated fatty acids. Volatile compounds were not affected by irradiation but increased with storage time indicating enhanced lipid oxidation. Colour parameters of samples remained unaffected immediately after irradiation. For samples packaged under a N(2) , atmosphere L and b values decreased during storage with a parallel increase of value a resulting to gradual product darkening especially in irradiated samples. Non-irradiated almonds retained acceptable quality for ca. 12 months stored at 20 °C with the O(2) absorber irrespective of lighting conditions and packaging material oxygen barrier. The respective shelf life for samples irradiated at 1.0 kGy was 12 months packaged in PET-SiOx//LDPE irrespective of lighting conditions and 12 months for samples irradiated at 3 kGy packaged in PET-SiOx//LDPE stored in the dark. Copyright © 2010 Society of Chemical Industry.

  4. Self-regulation of turbulence bursts and transport barriers

    International Nuclear Information System (INIS)

    Floriani, E; Ciraolo, G; Ghendrih, Ph; Sarazin, Y; Lima, R

    2013-01-01

    The interplay between turbulent bursts and transport barriers is analyzed with a simplified model of interchange turbulence in magnetically confined plasmas. The turbulent bursts spread into the transport barriers and, depending on the competing magnitude of the burst and stopping capability of the barrier, can burn through. Simulations of two models of transport barriers are presented: a hard barrier where interchange turbulence modes are stable in a prescribed region and a soft barrier with external plasma biasing. The response of the transport barriers to the non-linear perturbations of the turbulent bursts, addressed in a predator–prey approach, indicates that the barriers monitor an amplification factor of the turbulent bursts, with amplification smaller than one for most bursts and, in some cases, amplification factors that can significantly exceed unity. The weak barriers in corrugated profiles and magnetic structures, as well as the standard barriers, are characterized by these transmission properties, which then regulate the turbulent burst transport properties. The interplays of barriers and turbulent bursts are modeled as competing stochastic processes. For different classes of the probability density function (PDF) of these processes, one can predict the heavy tail properties of the bursts downstream from the barrier, either exponential for a leaky barrier, or with power laws for a tight barrier. The intrinsic probing of the transport barriers by the turbulent bursts thus gives access to the properties of the barriers. The main stochastic variables are the barrier width and the spreading distance of the turbulent bursts within the barrier, together with their level of correlation. One finds that in the case of a barrier with volumetric losses, such as radiation or particle losses as addressed in our present simulations, the stochastic model predicts a leaky behavior with an exponential PDF of escaping turbulent bursts in agreement with the simulation

  5. Anti-Microbial and Self-Cleaning Properties of Photocatalytic Surface Treatments and their Potential Use for Space-Based Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project was to implement a method to assess self-cleaning properties of commercially available photocatalytic surface treatments for their...

  6. Nagra technical report 14-02, Geological basics - Dossier VI - Barrier properties of proposed host rock sediments and neighbouring rock; SGT Etappe 2: Vorschlag weiter zu untersuchender geologischer Standortgebiete mit zugehörigen Standortarealen für die Oberflächenanlage -- Geologische Grundlagen -- Dossier VI -- Barriereneigenschaften der Wirt- und Rahmengesteine

    Energy Technology Data Exchange (ETDEWEB)

    Gautschi, A.; Deplazes, G.; Traber, D.; Marschall, P. [National Cooperative for the Disposal of Radioactive Waste (NAGRA), Wettingen (Switzerland); Mazurek, M.; Gimmi, T.; Maeder, U. [Institute of Geological Sciences, University of Berne, Berne (Switzerland)

    2014-12-15

    This dossier is the sixth of a series of eight reports concerning the safety and technical aspects of locations for the disposal of radioactive wastes in Switzerland. It discusses the barrier properties of the proposed host rock sediments and neighbouring rock layers. The mineralogical composition of the host rocks are discussed as are their pore densities and hydrological properties. Diffusion aspects are discussed. The aquifer systems in the proposed depository areas and their classification are looked at. The barrier properties of the host rocks and those of neighbouring sediments are discussed. Finally, modelling concepts and parameters for the transport of radionuclides in the rocks are discussed.

  7. Effect of sodium lactate /sodium diacetate in combination with sodium nitrite on physiochemical, microbial properties and sensory evaluation of cow sausage

    OpenAIRE

    Habib Sedghi; Ali Mohamadi Sani; Masood Najaf Najafi; Mohammad Ali Shariati

    2014-01-01

    Sodium nitrite has been always considered as one of the common additives due to its antibacterial effects on Clostridium botulinum and meat products' color, however it produces cancer creating nitrosamine. Recently, organic acids and their salts such as lactates have been employed as antimicrobial compounds. Lactates also improve organileptic properties including color, texture and taste and antioxidant properties. Sodium lactate causes to more reduction of anaerobic spore former bacteria tha...

  8. Cervical mucus properties stratify risk for preterm birth.

    Directory of Open Access Journals (Sweden)

    Agatha S Critchfield

    Full Text Available Ascending infection from the colonized vagina to the normally sterile intrauterine cavity is a well-documented cause of preterm birth. The primary physical barrier to microbial ascension is the cervical canal, which is filled with a dense and protective mucus plug. Despite its central role in separating the vaginal from the intrauterine tract, the barrier properties of cervical mucus have not been studied in preterm birth.To study the protective function of the cervical mucus in pret