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Sample records for chemically defined conditions

  1. Differentiation of human embryonic stem cells to regional specific neural precursors in chemically defined medium conditions.

    Directory of Open Access Journals (Sweden)

    Slaven Erceg

    Full Text Available BACKGROUND: Human embryonic stem cells (hESC provide a unique model to study early events in human development. The hESC-derived cells can potentially be used to replace or restore different tissues including neuronal that have been damaged by disease or injury. METHODOLOGY AND PRINCIPAL FINDINGS: The cells of two different hESC lines were converted to neural rosettes using adherent and chemically defined conditions. The progenitor cells were exposed to retinoic acid (RA or to human recombinant basic fibroblast growth factor (bFGF in the late phase of the rosette formation. Exposing the progenitor cells to RA suppressed differentiation to rostral forebrain dopamine neural lineage and promoted that of spinal neural tissue including motor neurons. The functional characteristics of these differentiated neuronal precursors under both, rostral (bFGF and caudalizing (RA signals were confirmed by patch clamp analysis. CONCLUSIONS/SIGNIFICANCE: These findings suggest that our differentiation protocol has the capacity to generate region-specific and electrophysiologically active neurons under in vitro conditions without embryoid body formation, co-culture with stromal cells and without presence of cells of mesodermal or endodermal lineages.

  2. Norepinephrine stimulates progesterone production in highly estrogenic bovine granulosa cells cultured under serum-free, chemically defined conditions

    Directory of Open Access Journals (Sweden)

    Piccinato Carla A

    2012-11-01

    Full Text Available Abstract Background Since noradrenergic innervation was described in the ovarian follicle, the actions of the intraovarian catecholaminergic system have been the focus of a variety of studies. We aimed to determine the gonadotropin-independent effects of the catecholamine norepinephrine (NE in the steroid hormone profile of a serum-free granulosa cell (GC culture system in the context of follicular development and dominance. Methods Primary bovine GCs were cultivated in a serum-free, chemically defined culture system supplemented with 0.1% polyvinyl alcohol. The culture features were assessed by hormone measurements and ultrastructural characteristics of GCs. Results GCs produced increasing amounts of estradiol and pregnenolone for 144h and maintained ultrastructural features of healthy steroidogenic cells. Progesterone production was also detected, although it significantly increased only after 96h of culture. There was a highly significant positive correlation between estradiol and pregnenolone production in high E2-producing cultures. The effects of NE were further evaluated in a dose–response study. The highest tested concentration of NE (10 (−7 M resulted in a significant increase in progesterone production, but not in estradiol or pregnenolone production. The specificity of NE effects on progesterone productio n was further investigated by incubating GCs with propranolol (10 (−8 M, a non-selective beta-adrenergic antagonist. Conclusions The present culture system represents a robust model to study the impact of intrafollicular factors, such as catecholamines, in ovarian steroidogenesis and follicular development. The results of noradrenergic effects in the steroidogenesis of GC have implications on physiological follicular fate and on certain pathological ovarian conditions such as cyst formation and anovulation.

  3. An effective freezing/thawing method for human pluripotent stem cells cultured in chemically-defined and feeder-free conditions.

    Science.gov (United States)

    Nishishita, Naoki; Muramatsu, Marie; Kawamata, Shin

    2015-01-01

    Culturing human Pluripotent Stem Cells (hPSC)s in chemically defined medium and feeder-free condition can facilitate metabolome and proteome analysis of culturing cells and medium, and reduce regulatory concerns for clinical application of cells. And in addition, if hPSC are passaged and cryopreserved in single cells it also facilitates quality control of cells at single cell level. Here we report a robust single cell freezing and thawing method of hPSCs cultured in chemically-defined medium TeSR(TM)-E8(TM) and on cost-effective recombinant human Vitronectin-N (rhVTN-N)-coated dish. Cells are dissociated into single cells with recombinant TrypLE(TM) Select and 0.5 mM EDTA/PBS (3:1 solution) in the presence of Rock inhibitor and cryopreserved with chemically defined CryoStem(TM). Approximately 60% of cells were viable after dissociation. Aggrewell(TM) 400 was used to form cell clumps of 500 cells after thaw in the presence of Rock inhibitor and cells were cultured for two days with TeSR-E8. Cells clumps were then seeded on rhVTN-N-coated dish and cultured with TeSR-E8 for two days prior to the first passage after thawing. Number of viable cells at the first passage increased around 10 times of that just before freezing. This robust single cell freezing method for hPSCs cultured in chemically defined medium will facilitate quality control of cultured cells at single cell level before cryopreservation and consequently assure the quality of cells in frozen vials for further manipulation after thawing. PMID:25973330

  4. Culture of bovine ovarian follicle wall sections maintained the highly estrogenic profile under basal and chemically defined conditions

    International Nuclear Information System (INIS)

    Follicle cultures reproduce in vitro the functional features observed in vivo. In a search for an ideal model, we cultured bovine antral follicle wall sections (FWS) in a serum-free defined medium (DM) known to induce 17β-estradiol (E2) production, and in a nondefined medium (NDM) containing serum. Follicles were sectioned and cultured in NDM or DM for 24 or 48 h. Morphological features were determined by light microscopy. Gene expression of steroidogenic enzymes and follicle-stimulating hormone (FSH) receptor were determined by RT-PCR; progesterone (P4) and E2 concentrations in the media were measured by radioimmunoassay. DM, but not NDM, maintained an FWS morphology in vitro that was similar to fresh tissue. DM also induced an increase in the expression of all steroidogenic enzymes, except FSH receptor, but NDM did not. In both DM and NDM, there was a gradual increase in P4 throughout the culture period; however, P4 concentration was significantly higher in NDM. In both media, E2 concentration was increased at 24 h, followed by a decrease at 48 h. The E2:P4 ratio was higher in DM than in NDM. These results suggest that DM maintains morphological structure, upregulates the expression of steroidogenic enzyme genes, and maintains steroid production with a high E2:P4 ratio in FWS cultures

  5. Culture of bovine ovarian follicle wall sections maintained the highly estrogenic profile under basal and chemically defined conditions

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, R.B. [Laboratório de Biotecnologia da Reprodução, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Salles, L.P. [Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Silva, I. Oliveira e; Gulart, L.V.M. [Laboratório de Biotecnologia da Reprodução, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Souza, D.K. [Laboratório de Biotecnologia da Reprodução, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Faculdade de Ceilândia, Universidade de Brasília, Ceilândia, DF (Brazil); Torres, F.A.G. [Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Bocca, A.L. [Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil); Silva, A.A.M. Rosa e [Laboratório de Biotecnologia da Reprodução, Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF (Brazil)

    2013-08-16

    Follicle cultures reproduce in vitro the functional features observed in vivo. In a search for an ideal model, we cultured bovine antral follicle wall sections (FWS) in a serum-free defined medium (DM) known to induce 17β-estradiol (E{sub 2}) production, and in a nondefined medium (NDM) containing serum. Follicles were sectioned and cultured in NDM or DM for 24 or 48 h. Morphological features were determined by light microscopy. Gene expression of steroidogenic enzymes and follicle-stimulating hormone (FSH) receptor were determined by RT-PCR; progesterone (P{sub 4}) and E{sub 2} concentrations in the media were measured by radioimmunoassay. DM, but not NDM, maintained an FWS morphology in vitro that was similar to fresh tissue. DM also induced an increase in the expression of all steroidogenic enzymes, except FSH receptor, but NDM did not. In both DM and NDM, there was a gradual increase in P{sub 4} throughout the culture period; however, P{sub 4} concentration was significantly higher in NDM. In both media, E{sub 2} concentration was increased at 24 h, followed by a decrease at 48 h. The E{sub 2}:P{sub 4} ratio was higher in DM than in NDM. These results suggest that DM maintains morphological structure, upregulates the expression of steroidogenic enzyme genes, and maintains steroid production with a high E{sub 2}:P{sub 4} ratio in FWS cultures.

  6. Defining and Measuring Chronic Conditions

    Centers for Disease Control (CDC) Podcasts

    2013-05-20

    This podcast is an interview with Dr. Anand Parekh, U.S. Department of Health and Human Services Deputy Assistant Secretary for Health, and Dr. Samuel Posner, Preventing Chronic Disease Editor in Chief, about the definition and burden of multiple chronic conditions in the United States.  Created: 5/20/2013 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 5/20/2013.

  7. Chemically defined medium and Caenorhabditis elegans

    Science.gov (United States)

    Szewczyk, Nathaniel J.; Kozak, Elena; Conley, Catharine A.

    2003-01-01

    BACKGROUND: C. elegans has been established as a powerful genetic system. Use of a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of use in large-scale growth and screening of animals. RESULTS: We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats to using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change the composition of the defined medium. CONCLUSIONS: As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  8. Chemical conditioning of sludge

    Energy Technology Data Exchange (ETDEWEB)

    Novak, John T.; Park, Chul

    2003-07-01

    With all the advances made in understanding the structure and composition of sewage sludges, chemical conditioning remains a trial and error process, both with regard to the type and dose of conditioner needed. Recent studies at Virginia Tech have found that biological floc consists of two types of biopolymer, material associated with iron and aluminum and material associated with calcium and magnesium. These materials behave differently when sludges undergo digestion. This results in very different material being released into solution during digestion and very different conditioning requirements. This study shows that the primary materials released during anaerobic digestion are proteins and coagulation of the colloidal protein fraction in solution is the primary mechanism for conditioning. For aerobically digested sludges, both proteins and polysaccharides make up the colloid fraction that interferes with dewatering. This research also shows that the effectiveness of the digestion process as characterized by volatile solids destruction is directly related to the chemical dose required for conditioning. That is, as the solids destruction increases, the conditioning chemical requirement also increases. Well-digested sludges dewater more poorly and require more conditioning chemical that those with less volatile solids destruction. (author)

  9. Chemical conditioning of sludge.

    Science.gov (United States)

    Novak, J T; Park, C

    2004-01-01

    With all the advances made in understanding the structure and composition of sewage sludges, chemical conditioning remains a trial and error process, both with regard to the type and dose of conditioner needed. Recent studies at Virginia Tech have found that biological floc consists of two types of biopolymer, material associated with iron and aluminium and material associated with calcium and magnesium. These materials behave differently when sludges undergo digestion. This results in very different material being released into solution during digestion and very different conditioning requirements. This study shows that the primary materials released during anaerobic digestion are proteins and coagulation of the colloidal protein fraction in solution is the primary mechanism for conditioning. For aerobically digested sludges, both proteins and polysaccharides make up the colloid fraction, which interferes with dewatering. This research also shows that the effectiveness of the digestion process as characterized by volatile solids destruction is directly related to the chemical dose required for conditioning. That is, as the solids destruction increases, the conditioning chemical requirement also increases. Well digested sludges dewater more poorly and require more conditioning chemical than those with less volatile solids destruction. PMID:15259940

  10. Sarcopenia: describing rather than defining a condition

    OpenAIRE

    Alchin, David Rhys

    2014-01-01

    Background Traditional definitions of sarcopenia have described an aging-associated disorder roughly defined as muscle mass two standard deviations below the young adult demographic. In an effort to clear the ambiguity pertaining to such descriptions, two international bodies have put forth working definitions of sarcopenia, namely The Society of Sarcopenia, Cachexia and Wasting Disorders in 2011, and The European Working Group on Sarcopenia in Older People in 2009. Review This paper will loo...

  11. Chemically Defined Medium and Caenorhabditis elegans: A Powerful Approach

    Science.gov (United States)

    Szewczyk, N. J.; Kozak, E.; Conley, C. A.

    2003-01-01

    C. elegans has been established as a powerful genetic system. Growth in a chemically defined medium (C. elegans Maintenance Medium (CeMM)) now allows standardization and systematic manipulation of the nutrients that animals receive. Liquid cultivation allows automated culturing and experimentation and should be of me in large-scale growth and screening of animals. Here we present our initial results from developing culture systems with CeMM. We find that CeMM is versatile and culturing is simple. CeMM can be used in a solid or liquid state, it can be stored unused for at least a year, unattended actively growing cultures may be maintained longer than with standard techniques, and standard C. elegans protocols work well with animals grown in defined medium. We also find that there are caveats of using defined medium. Animals in defined medium grow more slowly than on standard medium, appear to display adaptation to the defined medium, and display altered growth rates as they change defined medium composition. As was suggested with the introduction of C. elegans as a potential genetic system, use of defined medium with C. elegans should prove a powerful tool.

  12. Defining the Product Chemical Space of Monoterpenoid Synthases.

    Science.gov (United States)

    Tian, Boxue; Poulter, C Dale; Jacobson, Matthew P

    2016-08-01

    Terpenoid synthases create diverse carbon skeletons by catalyzing complex carbocation rearrangements, making them particularly challenging for enzyme function prediction. To begin to address this challenge, we have developed a computational approach for the systematic enumeration of terpenoid carbocations. Application of this approach allows us to systematically define a nearly complete chemical space for the potential carbon skeletons of products from monoterpenoid synthases. Specifically, 18758 carbocations were generated, which we cluster into 74 cyclic skeletons. Five of the 74 skeletons are found in known natural products; some of the others are plausible for new functions, either in nature or engineered. This work systematizes the description of function for this class of enzymes, and provides a basis for predicting functions of uncharacterized enzymes. To our knowledge, this is the first computational study to explore the complete product chemical space of this important class of enzymes. PMID:27517297

  13. Differentiation of purified astrocytes in a chemically defined medium

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, R.S.; de Vellis, J.

    1981-01-01

    Homogeneous cultures of astrocytes and oligodendrocytes provide an excellent model system for studying the regulation of glial structure and function. Recently, a chemically defined (CD) medium was developed for purified cultures of astrocytes, thus eliminating the requirement for serum and providing a controlled system for the study of astroglial properties. Due to the widespread use of astrocyte cultures and the potential benefits to be gained from using a defined medium, astrocyte cultures raised in CD medium were analyzed for purity as well as morphological and biochemical properties. Purity was assessed using immunocytochemical staining for glial fibrillary acidic protein (GFAP) and fibronectin. Astrocytes raised in CD medium are 95% pure using the expression of GFAP as a criterion. Fewer than 1% of the cells in CD medium stained positive for fibronectin eliminating the possibility that CD medium is selective for meningeal or endothelial cells. Astrocytes raised in CD medium exhibit a striking degree of morphological differentiation as seen in scanning electron micrographs. They also exhibit a high degree of biochemical differentiation illustrated by increases in the specific activity of S-100 protein and the induction of glutamine synthetase by glucocorticoids. A defined medium that supports the proliferation of rat astrocytes and enhances numerous morphological and biochemical properties should greatly facilitate the study of factors controlling glial proliferation and differentiation.

  14. Statistically defining optimal conditions of coagulation time of skim milk

    International Nuclear Information System (INIS)

    Milk consist huge amount of largely water and different proteins. Kappa-kazein of these milk proteins can be coagulated by Mucor miehei rennet enzyme, is an aspartic protease which cleavege 105 (phenly alanine)-106 (methionine) peptide bond. It is commonly used clotting milk proteins for cheese production in dairy industry. The aim of this study to measure milk clotting times of skim milk by using Mucor Miehei rennet and determination of optimal conditions of milk clotting time by mathematical modelling. In this research, milk clotting times of skim milk were measured at different pHs (3.0, 4.0, 5.0, 6.0, 7.0, 8.0) and temperatures (20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75 degree C). It was used statistical approach for defining best pH and temperature for milk clotting time of skim milk. Milk clotting activity was increase at acidic pHs and high temperatures. (author)

  15. Derivation and Maintenance of Murine Trophoblast Stem Cells under Defined Conditions

    OpenAIRE

    Caroline Kubaczka; Claire Senner; Marcos J. Araúzo-Bravo; Neha Sharma; Peter Kuckenberg; Astrid Becker; Andreas Zimmer; Oliver Brüstle; Michael Peitz; Myriam Hemberger; Hubert Schorle

    2014-01-01

    Summary Trophoblast stem cells (TSCs) are in vitro equivalents to the precursor cells of the placenta. TSCs are cultured in serum-rich medium with fibroblast growth factor 4, heparin, and embryonic-fibroblast-conditioned medium. Here, we developed a simple medium consisting of ten chemically defined ingredients for culture of TSCs on Matrigel or synthetic substrates, named TX medium. Gene expression and DNA methylation profiling demonstrated the faithful propagation of expression profiles and...

  16. Pavlovian conditioning and multiple chemical sensitivity.

    OpenAIRE

    Siegel, S.; Kreutzer, R

    1997-01-01

    Pavlovian conditioning processes may contribute to some symptoms of multiple chemical sensitivity (MCS). This review summarizes the potential relevance of the literature on conditional taste and olfactory aversions, conditional sensitization, and conditional immunomodulation to understanding MCS. A conditioning-based perspective on MCS suggests novel research and treatment strategies.

  17. Derivation of iPSCs after culture of human dental pulp cells under defined conditions.

    Directory of Open Access Journals (Sweden)

    Tomoko Takeda-Kawaguchi

    Full Text Available Human dental pulp cells (hDPCs are a promising resource for regenerative medicine and tissue engineering and can be used for derivation of induced pluripotent stem cells (iPSCs. However, current protocols use reagents of animal origin (mainly fetal bovine serum, FBS that carry the potential risk of infectious diseases and unwanted immunogenicity. Here, we report a chemically defined protocol to isolate and maintain the growth and differentiation potential of hDPCs. hDPCs cultured under these conditions showed significantly less primary colony formation than those with FBS. Cell culture under stringently defined conditions revealed a donor-dependent growth capacity; however, once established, the differentiation capabilities of the hDPCs were comparable to those observed with FBS. DNA array analyses indicated that the culture conditions robustly altered hDPC gene expression patterns but, more importantly, had little effect on neither pluripotent gene expression nor the efficiency of iPSC induction. The chemically defined culture conditions described herein are not perfect serum replacements, but can be used for the safe establishment of iPSCs and will find utility in applications for cell-based regenerative medicine.

  18. Defining food sampling strategy for chemical risk assessment

    OpenAIRE

    Wesolek, Nathalie; Roudot, Alain-Claude

    2012-01-01

    International audience Collection of accurate and reliable data is a prerequisite for informed risk assessment and risk management. For chemical contaminants in food, contamination assessments enable consumer protection and exposure assessments. And yet, the accuracy of a contamination assessment depends on both chemical analysis and sampling plan performance. A sampling plan is always used when the contamination level of a food lot is evaluated, due to the fact that the whole lot can not ...

  19. Possible interrelations among chemical freezeout conditions

    CERN Document Server

    Tawfik, A; Habashy, D M; Mohamed, M T; Abbas, E

    2016-01-01

    At thermal equilibrium, different chemical freezeout conditions have been proposed so far. They have an ultimate aim of proposing a universal description for the chemical freezeout parameters ($T_{ch}$ and $\\mu_b$), which are to be extracted from the statistical fitting of different particle ratios measured at various collision energies with calculations from thermal models. A systematic comparison between these conditions is presented. The physical meaning of each of them and their sensitivity to the hadron mass cuts are discussed. Based on availability, some of them are compared with recent lattice calculations. We found that most of these conditions are thermodynamically equivalent, especially at small baryon chemical potential. We propose that further crucial consistency tests should be performed at low energies. The fireball thermodynamics is another way of guessing conditions describing the chemical freezeout parameters extracted from high-energy experiments. We endorse the possibility that the various ...

  20. A statistical approach to define some tofu processing conditions

    Directory of Open Access Journals (Sweden)

    Vera de Toledo Benassi

    2011-12-01

    Full Text Available The aim of this work was to make tofu from soybean cultivar BRS 267 under different processing conditions in order to evaluate the influence of each treatment on the product quality. A fractional factorial 2(5-1 design was used, in which independent variables (thermal treatment, coagulant concentration, coagulation time, curd cutting, and draining time were tested at two different levels. The response variables studied were hardness, yield, total solids, and protein content of tofu. Polynomial models were generated for each response. To obtain tofu with desirable characteristics (hardness ~4 N, yield 306 g tofu.100 g-1 soybeans, 12 g proteins.100 g-1 tofu and 22 g solids.100 g-1 tofu, the following processing conditions were selected: heating until boiling plus 10 minutes in water bath, 2% dihydrated CaSO4 w/w, 10 minutes coagulation, curd cutting, and 30 minutes draining time.

  1. Defining goals and conditions for a sustainable world.

    OpenAIRE

    Cairns, J.

    1997-01-01

    Sustainable development is being approached component by component--socioeconomic, sustainable agriculture, transportation, forestry, energy use, cities, and the like--but, leaving a habitable planet for future generations will require the development of a widely shared paradigm. Further, the paradigm should be ecological from a scientific point of view. This development will be facilitated by a discussion of goals and those conditions necessary to meet them. The presently shared paradigm is ...

  2. Chemical characterization of a marine conditioning film

    Digital Repository Service at National Institute of Oceanography (India)

    Garg, A.; Jain, A.; Bhosle, N.B.

    in marine waters. Abundance and composition of neutral sugars and its composition are useful tools to assess the sources of organic matter (Cowie and Hedges, 1984; Skoog and Benner, 1997; D’Souza et al., 2005). Carbohydrate polymers appear to play... procedures and substratum surface properties may influence the chemical composition and the amount of the adsorbed material (Little and Zsolnay, 1985; Taylor et al., 1997; Compere et al., 2001). Changes in the chemical composition of the conditioning film...

  3. Define optimal conditions for steam generator tube integrity and an extended steam generator service life

    International Nuclear Information System (INIS)

    Steam generator (SG) tubing materials are susceptible to corrosion degradation in certain electrochemical corrosion potential regions in the presence of some aggressive ions. Because of the hideout of impurities, the local chemistry conditions in areas under sludge and inside SG crevices may be very aggressive with high concentrations of chlorides and other impurities. These areas are the locations where SG tubing materials are susceptible to degradation such as pitting, crevice corrosion, intergranular attack (IGA) and stress corrosion cracking (SCC). The corrosion susceptibility of each SG alloy is different and is a function of the electrochemical corrosion potential (ECP) and chemical environment. Electrochemical corrosion behaviors of major SG tube alloys were studied under some plausible aggressive crevice chemistry conditions. The possible hazardous conditions leading to SG tube degradation and the conditions, which can minimize SG tube degradation have been determined. Optimal operating conditions in the form of a 'Recommended ECP/pH zone' for minimizing corrosion degradation have been defined for all major SG tube materials, including Alloys 600, 800, 690 and 400, under CANDU SG operating and startup conditions. SCC tests and accelerated corrosion tests were carried out to verify and revise the recommended ECP/pH zones. This information is being incorporated into ChemAND, a system health monitor for plant chemistry management developed by AECL, which alloys utilities to evaluate the status of the SG alloys and to minimize SG material degradation by appropriate SG water chemistry management. (author)

  4. It is what it eats: Chemically defined media and the history of surrounds.

    Science.gov (United States)

    Landecker, Hannah

    2016-06-01

    The cultivation of living organs, cells, animals, and embryos in the laboratory has been central to the production of biological knowledge. Over the twentieth century, the drive to variance control in the experimental setting led to systematic efforts to generate synthetic, chemically defined substitutes for complex natural foods, housing, and other substrates of life. This article takes up the history of chemically defined media with three aims in mind. First, to characterize patterns of decontextualization, tinkering, and negotiation between life and experimenter that occur across disparate histories of cultivation. Second, to highlight the paradoxical historicity of cultivated organisms generated to be freed from context, as they incorporate and embody the purified amino acids, vitamins, plastics, and other artificial supports developed in the name of experimental control. Third, to highlight the figure-ground reversal that occurs as these cells and organisms are reconsidered as accidentally good models of life in industrialized conditions of pollution and nutrient excess, due to the man-made nature of their surrounds. Methodologically, the history of surrounds is described as an epigenetic approach that focuses on the material relations between different objects and organisms previously considered quite separately, from explanted organs to bacteria to plant cells to rats to human embryos. PMID:26992285

  5. Variations in Humanized and Defined Culture Conditions Supporting Derivation of New Human Embryonic Stem Cell Lines

    DEFF Research Database (Denmark)

    Fletcher, Judy M; Ferrier, Patricia M; Gardner, John O;

    2006-01-01

    The evolution of "humanized" (i.e., free of animal sourced reagents) and ultimately chemically defined culture systems for human embryo stem cell (hESC) isolation and culture is of importance to improving their efficacy and safety in research and therapeutic applications. This can be achieved by......ESC derivation, namely the use of animal immune compliment to isolate embryo inner cell mass, and animal sourced serum products and feeder cells to sustain hESC growth and attachment. As a result we report the derivation of six new hESC lines isolated by outgrowth from whole blastocysts on an extracellular...... serum-free medium (SFM) containing only human sourced and recombinant protein. Further, outgrowth of embryonic cells from whole blastocysts in both media could be achieved for up to 1 week without reliance on feeder cells. All variant conditions sustained undifferentiated cell status, a stable karyotype...

  6. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions

    OpenAIRE

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M.; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C.; Alexander, Morgan R.; Langer, Robert; Anderson, Daniel G.; Jaenisch, Rudolf

    2011-01-01

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell...

  7. A new chemically defined medium for the growth and sporulation of Bacillus cereus strains in anaerobiosis

    OpenAIRE

    Abbas, Amina aïcha; Tichit-Planchon, Stella; Jobin, Michel

    2014-01-01

    A new chemically defined liquid medium, MODS, was developed for the aerobic growth and anaerobic growth and sporulation of Bacillus cereus strains. The comparison of sporulation capacity of 18 strains of B. cereus has shown effective growth and spore production in anaerobiosis.

  8. Large-scale production of megakaryocytes from human pluripotent stem cells by chemically defined forward programming.

    Science.gov (United States)

    Moreau, Thomas; Evans, Amanda L; Vasquez, Louella; Tijssen, Marloes R; Yan, Ying; Trotter, Matthew W; Howard, Daniel; Colzani, Maria; Arumugam, Meera; Wu, Wing Han; Dalby, Amanda; Lampela, Riina; Bouet, Guenaelle; Hobbs, Catherine M; Pask, Dean C; Payne, Holly; Ponomaryov, Tatyana; Brill, Alexander; Soranzo, Nicole; Ouwehand, Willem H; Pedersen, Roger A; Ghevaert, Cedric

    2016-01-01

    The production of megakaryocytes (MKs)-the precursors of blood platelets-from human pluripotent stem cells (hPSCs) offers exciting clinical opportunities for transfusion medicine. Here we describe an original approach for the large-scale generation of MKs in chemically defined conditions using a forward programming strategy relying on the concurrent exogenous expression of three transcription factors: GATA1, FLI1 and TAL1. The forward programmed MKs proliferate and differentiate in culture for several months with MK purity over 90% reaching up to 2 × 10(5) mature MKs per input hPSC. Functional platelets are generated throughout the culture allowing the prospective collection of several transfusion units from as few as 1 million starting hPSCs. The high cell purity and yield achieved by MK forward programming, combined with efficient cryopreservation and good manufacturing practice (GMP)-compatible culture, make this approach eminently suitable to both in vitro production of platelets for transfusion and basic research in MK and platelet biology. PMID:27052461

  9. Operators defined by conditional expectations and random measures / Daniel Thanyani Rambane

    OpenAIRE

    Rambane, Daniel Thanyani

    2004-01-01

    This study revolves around operators defined by conditional expectations and operators generated by random measures. Studies of operators in function spaces defined by conditional expectations first appeared in the mid 1950's by S-T.C. Moy [22] and S. Sidak [26]. N. Kalton studied them in the setting of Lp-spaces 0 < p < 1 in [15, 131 and in L1-spaces, [14], while W. Arveson [5] studied them in L2-spaces. Their averaging properties were studied by P.G. Dodds and C.B. Huijsma...

  10. Developmental competence and cryotolerance of caprine parthenogenetic embryos cultured in chemically defined media.

    Science.gov (United States)

    Choi, Woo-Jae; Lee, Ji-Hyun; Lee, Sang-Hee; Yum, Soo-Young; Lee, Song-Jeon; Lim, Chae-Woong; Jang, Goo

    2016-07-15

    In animal reproduction technologies, the in vitro embryo culture system has advanced over the past few decades. However, in vitro cultured embryos still have reduced functional and physiological abilities compared with those from in vivo conditions, and many factors of oviduct and uterine environments have not yet been revealed. Here, we demonstrated the in vitro culture of domestic goat (Capra hircus) embryos using two types of culture media, modified synthetic oviductal fluid (mSOF) and a two-step chemically defined medium (DI/II). To obtain parthenogenetic goat embryos, oocytes were matured in vitro in tissue culture media-199 supplemented with 10% fetal bovine serum for 22 to 24 hours, and activated with 5 μM, Ca(2+) ionomycin for 4 minutes, followed by 1.9 mM, 6-dimethylaminopurine treatment for 4 hours. After 2 days of embryo culture in different culture media, there were no significant differences in cleavage rates (96.6% vs. 95.4% in mSOF vs. DI/II, respectively). However, the DI/II group showed improved development competence to blastocysts (64.6% vs. 82.3% in mSOF vs. DI/II, respectively) and the total cell number of blastocysts (144.3 ± 9.2 vs. 264.4 ± 15.2 in mSOF vs. DI/II, respectively) at Day 7. After the cryopreservation of early-stage blastocysts at Day 6 via the conventional slow-freezing procedure, the surviving embryos were analyzed. The re-expansion rate after freezing and thawing was significantly higher in DI/II (39.66% vs. 67.69% in mSOF vs. DI/II, respectively), but there were no statistical differences in total cell numbers (142.3 ± 12.1 vs. 172.1 ± 11.6 in mSOF vs. DI/II, respectively), apoptotic index (4.9 ± 0.8% vs. 3.8 ± 0.7 in mSOF vs. DI/II, respectively), and the gene expression levels (BAX, GLUT1, MnSOD, and OCT4) among the re-expanded blastocysts. Overall, our data reported that the defined in vitro culture media for goat embryos were established with high efficiency, which will be very useful for

  11. How do we define the condition ‘recurrent low back pain’? A systematic review

    OpenAIRE

    Stanton, Tasha R.; Latimer, Jane; Maher, Chris G; Hancock, Mark J.

    2009-01-01

    Recurrent low back pain (recurrent LBP) is a common condition, however, it is unclear if uniform definitions are used in studies investigating the prevalence and management of this condition. The aim of this systematic review was to identify how recurrent LBP is defined in the literature. A literature search was performed on MEDLINE, EMBASE, CINAHL, AMED, and PEDro. Studies were considered eligible if they investigated a cohort of subjects with recurrent LBP or if they were measuring the prev...

  12. Surface-engineered substrates for improved human pluripotent stem cell culture under fully defined conditions.

    Science.gov (United States)

    Saha, Krishanu; Mei, Ying; Reisterer, Colin M; Pyzocha, Neena Kenton; Yang, Jing; Muffat, Julien; Davies, Martyn C; Alexander, Morgan R; Langer, Robert; Anderson, Daniel G; Jaenisch, Rudolf

    2011-11-15

    The current gold standard for the culture of human pluripotent stem cells requires the use of a feeder layer of cells. Here, we develop a spatially defined culture system based on UV/ozone radiation modification of typical cell culture plastics to define a favorable surface environment for human pluripotent stem cell culture. Chemical and geometrical optimization of the surfaces enables control of early cell aggregation from fully dissociated cells, as predicted from a numerical model of cell migration, and results in significant increases in cell growth of undifferentiated cells. These chemically defined xeno-free substrates generate more than three times the number of cells than feeder-containing substrates per surface area. Further, reprogramming and typical gene-targeting protocols can be readily performed on these engineered surfaces. These substrates provide an attractive cell culture platform for the production of clinically relevant factor-free reprogrammed cells from patient tissue samples and facilitate the definition of standardized scale-up friendly methods for disease modeling and cell therapeutic applications. PMID:22065768

  13. Development of an improved chemically defined minimal medium for Listeria monocytogenes.

    OpenAIRE

    Premaratne, R J; W.J. LIN; Johnson, E. A.

    1991-01-01

    A chemically defined minimal medium for Listeria monocytogenes has been developed by modification of Welshimer's medium. The growth factors required by L. monocytogenes Scott A are leucine, isoleucine, arginine, methionine, valine, cysteine (each at 100 mg/liter), riboflavin and biotin (each at 0.5 micrograms/ml), thiamine (1.0 micrograms/ml), and thioctic acid (0.005 micrograms/ml). Growth was stimulated by 20 micrograms of Fe3+ per ml as ferric citrate. Glucose (1%) and glutamine (600 mg/li...

  14. A paleolimnological perspective on liming – implications for defining reference conditions in Swedish lakes

    OpenAIRE

    Norberg, Matilda

    2009-01-01

    Using paleolimnological techniques, I have studied surface-water acidification and the effects of liming in Swedish lakes on a decadal to millennial time-scale. The overall objective was to contribute to the discussion on the fulfilment of goals within the Swedish liming program. One of the main goals of this program is to restore lakes to natural or nearly natural conditions, i.e. to a reference condition as termed in the EU Water Framework Directive. In this context, a key issue is to defin...

  15. Scalable cultivation of human pluripotent stem cells on chemically-defined surfaces

    Science.gov (United States)

    Hsiung, Michael Chi-Wei

    Human stem cells (SCs) are classified as self-renewing cells possessing great ability in therapeutic applications due of their ability to differentiate along any major cell lineage in the human body. Despite their restorative potential, widespread use of SCs is hampered by strenuous control issues. Along with the need for strict xeno-free environments to sustain growth in culture, current methods for growing human pluripotent stem cells (hPSCs) rely on platforms which impede large-scale cultivation and therapeutic delivery. Hence, any progress towards development of large-scale culture systems is severely hindered. In a concentrated effort to develop a scheme that can serve as a model precursor for large scale SC propagation in clinical use, we have explored methods for cultivating hPSCs on completely defined surfaces. We discuss novel approaches with the potential to go beyond the limitations presented by current methods. In particular, we studied the cultivation of human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs) on surface which underwent synthetic or chemical modification. Current methods for hPSCs rely on animal-based extracellular matrices (ECMs) such as mouse embryonic fibroblasts (MEFs) or feeders and murine sacoma cell-derived substrates to facilitate their growth. While these layers or coatings can be used to maximize the output of hPSC production, they cannot be considered for clinical use because they risk introducing foreign pathogens into culture. We have identified and developed conditions for a completely defined xeno-free substrate used for culturing hPSCs. By utilizing coupling chemistry, we can functionalize ester groups on a given surface and conjugate synthetic peptides containing the arginine-glycine-aspartic acid (RGD) motif, known for their role in cell adhesion. This method offers advantages over traditional hPSC culture by keeping the modified substrata free of xenogenic response and can be scaled up in

  16. Defining boundary conditions for RANS predictions of urban flows using mesoscale simulations

    Science.gov (United States)

    Garcia Sanchez, Clara; Gorle, Catherine; van Beeck, Jeroen

    2015-11-01

    Pollutant dispersion and wind flows in urban canopies are major concerns for human health and energy, and the complex nature of the flow and transport processes remains a challenge when using Computational Fluid Dynamics (CFD) to predict wind flows. The definition of the inflow boundary condition in Reynolds-Averaged Navier-Stokes simulations (RANS) is one of the uncertainties that will strongly influence the prediction of the flow field, and thus, the dispersion pattern. The goal of the work presented is to define a methodology that improves the level of realism in the inflow condition for RANS simulations by accounting for larger mesoscale effects. The Weather Research and Forecasting model (WRF) is used to forecast mesoscale flow patterns, and two different approaches are used to define inflow conditions for the RANS simulations performed with OpenFOAM: 1) WRF variables such as local velocity magnitude, ABL height and friction velocity are directly interpolated onto the boundaries of the CFD domain; 2) WRF predictions for the geostrophic wind and friction velocity are applied as a forcing boundary condition. Simulations of the Joint Urban 2003 experimental campaign in Oklahoma City have been performed using both approaches and a comparison of the results will be presented.

  17. Chemically Defined and Xeno-Free Cryopreservation of Human Adipose-Derived Stem Cells

    Science.gov (United States)

    López, Melany; Bollag, Roni J.; Yu, Jack C.; Isales, Carlos M.; Eroglu, Ali

    2016-01-01

    The stromal compartment of adipose tissue harbors multipotent cells known as adipose-derived stem cells (ASCs). These cells can differentiate into various lineages including osteogenic, chrondrogenic, adipogenic, and neurogenic; this cellular fraction may be easily obtained in large quantities through a clinically safe liposuction procedure. Therefore, ASCs offer exceptional opportunities for tissue engineering and regenerative medicine. However, current practices involving ASCs typically use fetal bovine serum (FBS)-based cryopreservation solutions that are associated with risks of immunological reactions and of transmitting infectious diseases and prions. To realize clinical applications of ASCs, serum- and xeno-free defined cryopreservation methods are needed. To this end, an animal product-free chemically defined cryopreservation medium was formulated by adding two antioxidants (reduced glutathione and ascorbic acid 2-phosphate), two polymers (PVA and ficoll), two permeating cryoprotectants (ethylene glycol and dimethylsulfoxide), a disaccharide (trehalose), and a calcium chelator (EGTA) to HEPES-buffered DMEM/F12. To limit the number of experimental groups, the concentration of trehalose, both polymers, and EGTA was fixed while the presence of the permeating CPAs and antioxidants was varied. ASCs suspended either in different versions of the defined medium or in the conventional undefined cryopreservation medium (10% dimethylsulfoxide+10% DMEM/F12+80% serum) were cooled to -70°C at 1°C/min before being plunged into liquid nitrogen. Samples were thawed either in air or in a water bath at 37°C. The presence of antioxidants along with 3.5% concentration of each penetrating cryoprotectant improved the freezing outcome to the level of the undefined cryopreservation medium, but the plating efficiency was still lower than that of unfrozen controls. Subsequently, increasing the concentration of both permeating cryoprotectants to 5% further improved the plating

  18. Antimycobacterial activity of chemically defined natural substances from the Caribbean flora in Guadeloupe.

    Science.gov (United States)

    Rastogi, N; Abaul, J; Goh, K S; Devallois, A; Philogène, E; Bourgeois, P

    1998-04-01

    Eight chemically defined, naturally occurring compounds were extracted from the tropical flora of the Caribbean island of Guadeloupe: pilocarpine, an alkaloid from Pilocarpus racemosus; heraclenol and isomeranzin, coumarins from Triphasia trifolia; lochnerin, an indole alkaloid from Rauwolfia biauriculata; ibogaine and voacangine, indole alkaloids from Tabernaemontana citrifolia; texalin, an oxazole from Amyris elemifera; and canellal, a sesquiterpene dialdehyde from Canella winterana. An essential oil fraction from Canella winterana was also tested. The antimycobacterial activity of these substances was tested against Mycobacterium tuberculosis, M. avium and M. kansasii using the Middlebrook 7H11 agar medium, the Bactec 460-TB radiometric methodology, and determination of bacterial viable counts. Three compounds, namely ibogaine, voacangine and texalin, showed antimycobacterial activity. Investigations on the structure-modification and structure-activity relationships of these compounds may help determine new targets for future drug development. PMID:9626931

  19. Chemically Defined Medium for the Accumulation of Intracellular Malate Dehydrogenase by Streptomyces aureofaciens

    OpenAIRE

    Laluce, Cecília; Ernandes, José Roberto; Molinari, Rubens

    1987-01-01

    A chemically defined medium was developed for the production of intracellular malate dehydrogenases by Streptomyces aureofaciens NRRL-B 1286. The composition of the medium (per liter) was as follows: 50 g of starch, 4 g of ammonium sulfate, 7.32 g of l-aspartic acid, 13.8 g of MgSO4 · 7H2O, 1.7 g of K2HPO4, 0.01 g of ZnSO4 · 7H2O, 0.01 g of FeSO4 · 7H2O, 0.01 g of MnSO4 · H2O, and 0.005 g of CoSO4 · 7H2O. The pH of the medium was adjusted to 6.7 to 7.0 after sterilization. The activity of the...

  20. Acetoin catabolism and acetylbutanediol formation by Bacillus pumilus in a chemically defined medium.

    Directory of Open Access Journals (Sweden)

    Zijun Xiao

    Full Text Available BACKGROUND: Most low molecular diols are highly water-soluble, hygroscopic, and reactive with many organic compounds. In the past decades, microbial research to produce diols, e.g. 1,3-propanediol and 2,3-butanediol, were considerably expanded due to their versatile usages especially in polymer synthesis and as possible alternatives to fossil based feedstocks from the bioconversion of renewable natural resources. This study aimed to provide a new way for bacterial production of an acetylated diol, i.e. acetylbutanediol (ABD, 3,4-dihydroxy-3-methylpentan-2-one, by acetoin metabolism. METHODOLOGY/PRINCIPAL FINDINGS: When Bacillus pumilus ATCC 14884 was aerobically cultured in a chemically defined medium with acetoin as the sole carbon and energy source, ABD was produced and identified by gas chromatography--chemical ionization mass spectrometry and NMR spectroscopy. CONCLUSIONS/SIGNIFICANCE: Although the key enzyme leading to ABD from acetoin has not been identified yet at this stage, this study proposed a new metabolic pathawy to produce ABD in vivo from using renewable resources--in this case acetoin, which could be reproduced from glucose in this study--making it the first facility in the world to prepare this new bio-based diol product.

  1. Development of a chemically defined serum-free medium for differentiation of rat adipose precursor cells

    International Nuclear Information System (INIS)

    Stromal-vascular cells from the epididymal fat pad of 4-week-old rats, when cultured in a medium containing insulin or insulin-like growth factor, IFG-I, triiodothyronine and transferrin, were able to undergo adipose conversion. Over ninety percent of the cells accumulated lipid droplets and this proportion was reduced in serum-supplemented medium. The adipose conversion was assessed by the development of lipoprotein lipase (LPL) and glycerol-3-phosphate dehydrogenase (GPDH) activities, [14]glucose incorporation into polar and neutral lipids, triacylglycerol accumulation and lipolysis in response to isoproterenol. Similar results were obtained with stromal-vascular cells from rat subcutaneous and retroperitoneal adipose tissues. Stromal-vascular cells required no adipogenic factors in addition to the components of the serum-free medium. Insulin was required within a physiological range of concentrations for the emergence of LPL and at higher concentrations for that of GPDH. When present at concentrations ranging from 2 to 50 nM, IGF-I was able to replace insulin for the expression of both LPL and and GPDH. The development of a serum free, chemically defined medium for the differentiation of diploid adiopose precursor cells opens up the possibility of characterizing inhibitors or activators of the adipose conversion process

  2. Development of a chemically defined serum-free medium for differentiation of rat adipose precursor cells

    Energy Technology Data Exchange (ETDEWEB)

    Deslex, S.; Negrel, R.; Ailhaud, G.

    1987-01-01

    Stromal-vascular cells from the epididymal fat pad of 4-week-old rats, when cultured in a medium containing insulin or insulin-like growth factor, IFG-I, triiodothyronine and transferrin, were able to undergo adipose conversion. Over ninety percent of the cells accumulated lipid droplets and this proportion was reduced in serum-supplemented medium. The adipose conversion was assessed by the development of lipoprotein lipase (LPL) and glycerol-3-phosphate dehydrogenase (GPDH) activities, (/sup 14/)glucose incorporation into polar and neutral lipids, triacylglycerol accumulation and lipolysis in response to isoproterenol. Similar results were obtained with stromal-vascular cells from rat subcutaneous and retroperitoneal adipose tissues. Stromal-vascular cells required no adipogenic factors in addition to the components of the serum-free medium. Insulin was required within a physiological range of concentrations for the emergence of LPL and at higher concentrations for that of GPDH. When present at concentrations ranging from 2 to 50 nM, IGF-I was able to replace insulin for the expression of both LPL and and GPDH. The development of a serum free, chemically defined medium for the differentiation of diploid adiopose precursor cells opens up the possibility of characterizing inhibitors or activators of the adipose conversion process.

  3. TRAK ontology: defining standard care for the rehabilitation of knee conditions.

    Science.gov (United States)

    Button, Kate; van Deursen, Robert W; Soldatova, Larisa; Spasić, Irena

    2013-08-01

    In this paper we discuss the design and development of TRAK (Taxonomy for RehAbilitation of Knee conditions), an ontology that formally models information relevant for the rehabilitation of knee conditions. TRAK provides the framework that can be used to collect coded data in sufficient detail to support epidemiologic studies so that the most effective treatment components can be identified, new interventions developed and the quality of future randomized control trials improved to incorporate a control intervention that is well defined and reflects clinical practice. TRAK follows design principles recommended by the Open Biomedical Ontologies (OBO) Foundry. TRAK uses the Basic Formal Ontology (BFO) as the upper-level ontology and refers to other relevant ontologies such as Information Artifact Ontology (IAO), Ontology for General Medical Science (OGMS) and Phenotype And Trait Ontology (PATO). TRAK is orthogonal to other bio-ontologies and represents domain-specific knowledge about treatments and modalities used in rehabilitation of knee conditions. Definitions of typical exercises used as treatment modalities are supported with appropriate illustrations, which can be viewed in the OBO-Edit ontology editor. The vast majority of other classes in TRAK are cross-referenced to the Unified Medical Language System (UMLS) to facilitate future integration with other terminological sources. TRAK is implemented in OBO, a format widely used by the OBO community. TRAK is available for download from http://www.cs.cf.ac.uk/trak. In addition, its public release can be accessed through BioPortal, where it can be browsed, searched and visualized. PMID:23665300

  4. Developmental features of rat cerebellar neural cells cultured in a chemically defined medium

    International Nuclear Information System (INIS)

    We studied some aspects of the differentiation of rat cerebellar neural cells obtained from 8-day postnatal animals and cultured in a serum-free, chemically defined medium (CDM). The ability of the cells to take up radioactive transmitter amino acids was analyzed autoradiographically. The L-glutamate analogue 3H-D-aspartate was taken up by astroglial cells, but not by granule neurons, even in late cultures (20 days in vitro). This is in agreement with the lack of depolarization-induced release of 3H-D-aspartate previously observed in this type of culture. In contrast, 3H-(GABA) was scarcely accumulated by glial-fibrillary-acidic-protein (GFAP)-positive astrocytes, but taken up by glutamate-decarboxylase-positive inhibitory interneurons and was released in a Ca2+-dependent way upon depolarization: 3H-GABA evoked release progressively increased with time in culture. Interestingly, the expression of the vesicle-associated protein synapsin I was much reduced in granule cells cultured in CDM as compared to those maintained in the presence of serum. These data would indicate that in CDM the differentiation of granule neurons is not complete, while that of GABAergic neurons is not greatly affected. Whether the diminished differentiation of granule cells must be attributed only to serum deprivation or also to other differences in the composition of the culture medium remains to be established. 3H-GABA was avidly taken up also by a population of cells which were not recognized by antibodies raised against GFAP, glutamate decarboxylase, and microtubule-associated protein 2. These cells have been characterized as bipotential precursors of oligodendrocytes and of a subpopulation of astrocytes bearing a stellate shape and capable of high-affinity 3H-GABA uptake

  5. Comparison of diagnostic tests in distinct well-defined conditions related to dry eye disease.

    Directory of Open Access Journals (Sweden)

    Monica Alves

    Full Text Available PURPOSE: This study compares signs, symptoms and predictive tools used to diagnose dry eye disease (DED and ocular surface disorders in six systemic well-defined and non-overlapping diseases. It is well known that these tests are problematic because of a lack of agreement between them in identifying these conditions. Accordingly, we provide here a comparative clinical profile analysis of these different diseases. METHODS: A spontaneous and continuous sample of patients with Sjögren's syndrome (SS (n=27, graft-versus-host-disease (GVHD (n=28, Graves orbitopathy (n=28, facial palsy (n=8, diabetes mellitus without proliferative retinopathy (n=14 and glaucoma who chronically received topical drugs preserved with benzalkonium chloride (n=20 were enrolled. Evaluation consisted of a comprehensive protocol encompassing: (1 structured questionnaire - Ocular Surface Disease Index (OSDI; (2 tear osmolarity (TearLab Osmolarity System - Ocusense; (3 tear film break-up time (TBUT; (4 fluorescein and lissamine green staining; (5 Schirmer test and (6 severity grading. RESULTS: One hundred and twenty five patients (aged 48.8 years-old ± 14.1, male:female ratio=0.4 were enrolled in the study, along with 24 age and gender matched controls. Higher scores on DED tests were obtained in Sjögren Syndrome (P<0.05, except for tear film osmolarity that was higher in diabetics (P<0.001 and fluorescein staining, that was higher in facial palsy (P<0.001. TFBUT and OSDI correlated better with other tests. The best combination of diagnostic tests for DED was OSDI, TBUT and Schirmer test (sensitivity 100%, specificity 95% and accuracy 99.3%. CONCLUSIONS: DED diagnostic test results present a broad range of variability among different conditions. Vital stainings and TBUT correlated best with one another whereas the best test combination to detect DED was: OSDI/TBUT/Schirmer.

  6. Validity conditions for moment closure approximations in stochastic chemical kinetics

    OpenAIRE

    Schnoerr, David; Sanguinetti, Guido; Grima, Ramon

    2014-01-01

    Approximations based on moment-closure (MA) are commonly used to obtain estimates of the mean molecule numbers and of the variance of fluctuations in the number of molecules of chemical systems. The advantage of this approach is that it can be far less computationally expensive than exact stochastic simulations of the chemical master equation. Here, we numerically study the conditions under which the MA equations yield results reflecting the true stochastic dynamics of the system. We show tha...

  7. Validity conditions for moment closure approximations in stochastic chemical kinetics

    International Nuclear Information System (INIS)

    Approximations based on moment-closure (MA) are commonly used to obtain estimates of the mean molecule numbers and of the variance of fluctuations in the number of molecules of chemical systems. The advantage of this approach is that it can be far less computationally expensive than exact stochastic simulations of the chemical master equation. Here, we numerically study the conditions under which the MA equations yield results reflecting the true stochastic dynamics of the system. We show that for bistable and oscillatory chemical systems with deterministic initial conditions, the solution of the MA equations can be interpreted as a valid approximation to the true moments of the chemical master equation, only when the steady-state mean molecule numbers obtained from the chemical master equation fall within a certain finite range. The same validity criterion for monostable systems implies that the steady-state mean molecule numbers obtained from the chemical master equation must be above a certain threshold. For mean molecule numbers outside of this range of validity, the MA equations lead to either qualitatively wrong oscillatory dynamics or to unphysical predictions such as negative variances in the molecule numbers or multiple steady-state moments of the stationary distribution as the initial conditions are varied. Our results clarify the range of validity of the MA approach and show that pitfalls in the interpretation of the results can only be overcome through the systematic comparison of the solutions of the MA equations of a certain order with those of higher orders

  8. The association between combination antiretroviral adherence and AIDS-defining conditions at HIV diagnosis.

    Science.gov (United States)

    Abara, Winston E; Xu, Junjun; Adekeye, Oluwatoyosi A; Rust, George

    2016-08-01

    Combination antiretroviral therapy (cART) has changed the clinical course of HIV. AIDS-defining conditions (ADC) are suggestive of severe or advanced disease and are a leading cause of HIV-related hospitalizations and death among people living with HIV/AIDS (PLWHA) in the USA. Optimal adherence to cART can mitigate the impact of ADC and disease severity on the health and survivability of PLWHA. The objective of this study was to evaluate the association between ADC at HIV diagnosis and optimal adherence among PLWHA. Using data from the 2008 and 2009 Medicaid data from 29 states, we identified individuals, between 18 and 49 years, recently infected with HIV and with a cART prescription. Frequencies and descriptive statistics were conducted to characterize sample. Univariate and multivariable Poisson regression analyses were employed to evaluate the association optimal cART adherence (defined as ≥ 95% study days covered by cART) and ADC at HIV diagnosis (≥1 ADC) were assessed. Approximately 17% of respondents with ADC at HIV diagnosis reported optimal cART adherence. After adjusting for covariates, respondents with an ADC at HIV diagnosis were less likely to report optimal cART adherence (adjusted prevalence ratio (APR) = 0.64, 95% confidence intervals (CI), 0.54-0.75). Among the covariates, males (APR=1.10, 95% CI, 1.02-1.19) compared to females were significantly more likely to report optimal adherence while younger respondents, 18-29 years (APR=0.67, 95% CI, 0.57-0.77), 30-39 years (APR=0.86, 95% CI, 0.79-0.95) compared to older respondents were significantly less likely to report optimal adherence. PLWHA with ADC at HIV diagnosis are at risk of suboptimal cART adherence. Multiple adherence strategies that include healthcare providers, case managers, and peer navigators should be utilized to improve cART adherence and optimize health outcomes among PLWHA with ADC at HIV diagnosis. Targeted adherence programs and services are required to address

  9. Protocol optimization for long-term liquid storage of goat semen in a chemically defined extender.

    Science.gov (United States)

    Zhao, B-T; Han, D; Xu, C-L; Luo, M-J; Chang, Z-L; Tan, J-H

    2009-12-01

    A specific problem in the preservation of goat semen has been the detrimental effect of seminal plasma on the viability of spermatozoa in extenders containing egg yolk or milk. The use of chemically defined extenders will have obvious advantages in liquid storage of buck semen. Our previous study showed that the self-made mZAP extender performed better than commercial extenders, and maintained a sperm motility of 34% for 9 days and a fertilizing potential for successful pregnancies for 7 days. The aim of this study was to extend the viability and fertilizing potential of liquid-stored goat spermatozoa by optimizing procedures for semen processing and storage in the mZAP extender. Semen samples collected from five goat bucks of the Lubei White and Boer breeds were diluted with the extender, cooled and stored at 5 degrees C. Stored semen was evaluated for sperm viability parameters, every 48 h of storage. Data from three ejaculates of different bucks were analysed for each treatment. The percentage data were arcsine-transformed before being analysed with anova and Duncan's multiple comparison test. While cooling at the rate of 0.1-0.25 degrees C/min did not affect sperm viability parameters, doing so at the rate of 0.6 degrees C/min from 30 to 15 degrees C reduced goat sperm motility and membrane integrity. Sperm motility and membrane integrity were significantly higher in semen coated with the extender containing 20% egg yolk than in non-coated semen. Sperm motility, membrane integrity and acrosomal intactness were significantly higher when coated semen was 21-fold diluted than when it was 11- or 51-fold diluted and when extender was renewed at 48-h intervals than when it was not renewed during storage. When goat semen coated with the egg yolk-containing extender was 21-fold diluted, cooled at the rate of 0.07-0.25 degrees C/min, stored at 5 degrees C and the extender renewed every 48 h, a sperm motility of 48% was maintained for 13 days, and an in vitro

  10. Why do patients visit their doctors? Assessing the most prevalent conditions in a defined US population

    Science.gov (United States)

    St. Sauver, Jennifer L.; Warner, David O.; Yawn, Barbara P.; Jacobson, Debra J.; Mc Gree, Michaela E.; Pankratz, Joshua J.; Melton, L. Joseph; Roger, Véronique L.; Ebbert, Jon O.; Rocca, Walter A.

    2013-01-01

    Objective To describe the prevalence of non-acute conditions among patients seeking healthcare in a defined US population, emphasizing age, sex, and ethnic differences. Methods The Rochester Epidemiology Project (REP) records-linkage system was used to identify all residents of Olmsted County, MN on April 1, 2009 (n=142,377). We then electronically extracted all International Classification of Diseases, ninth revision (ICD-9) codes received by these subjects from any health care provider between January 1, 2005 and December 31, 2009. We grouped ICD-9 codes into Clinical Classification Codes (CCCs), and then into 47 broader disease groups associated with health-related quality of life. Age- and sex-specific prevalence was estimated by dividing the number of individuals within each group by the corresponding age- and sex-specific population. People with multiple codes within a group were counted only once. Results We included a total of 142,377 subjects (53% women). Skin disorders (42.7%), osteoarthritis and joint disorders (33.6%), back problems (23.9%), disorders of lipid metabolism (22.4%), and upper respiratory disease (22.1%; excluding asthma) were the most prevalent disease groups in this population. Eight of the 10 most prevalent disease groups were more common in women; however, disorders of lipid metabolism and hypertension were more common in men. Additionally, the prevalence of seven of these 10 groups increased with advancing age. Prevalence varied also across whites, blacks, and Asians. Conclusion Our findings suggest areas for focused research that may lead to better care delivery and improved population health. PMID:23274019

  11. Risk management of exposure to chemicals under operational conditions

    NARCIS (Netherlands)

    Langenberg, J.P.

    2007-01-01

    The HFM panel has decided to install an Exploratory Team, ET-078, which should advise whether or not a Technical Group (TG) should be established on the subject of risk management of exposure to chemicals under operational conditions. This paper described the context and approach of ET-078.

  12. Acidification in the Adirondacks: Defining the Biota in trophic Levels of 30 Chemically Diverse Acid-Impacted Lakes

    Science.gov (United States)

    The Adirondack Mountains in New York State have a varied surficial geology and chemically diverse surface waters that are among the most impacted by acid deposition in the U.S. No single Adirondack investigation has been comprehensive in defining the effects of acidification on ...

  13. The Effects of Defined Benefit Pension Incentives and Working Conditions on Teacher Retirement Decisions

    OpenAIRE

    Joshua Furgeson; Strauss, Robert P.; Vogt, William B.

    2006-01-01

    The retirement behavior of Pennsylvania public school teachers in 1997–98 and 1998–99, a period when state early retirement incentives were temporarily increased, is modeled using a choice framework that emphasizes both pecuniary and nonpecuniary factors of the retirement decision under a defined benefit retirement plan. We find each to have large and statistically significant effects on the decision to retire. The present value of inflation-adjusted pension benefits of a public defined benef...

  14. Chemical flowsheet conditions for preparing urania spheres by internal gelation

    International Nuclear Information System (INIS)

    Small, ceramic urania spheres can be prepared for use as nuclear fuel by internal chemical gelation of uranyl nitrate solution droplets. Decomposition of hexamethylenetetramine (HMTA) dissolved in the uranyl nitrate solution releases ammonia to precipitate hydrated UO3. Previously established flowsheet conditions have been improved and modified at ORNL and have been applied to prepare dense UO2 spheres with average diameters of 1200, 300, and 30 μm

  15. Defining chemical expansion: the choice of units for the stoichiometric expansion coefficient

    DEFF Research Database (Denmark)

    Marrocchelli, Dario; Chatzichristodoulou, Christodoulos; Bishop, Sean R.

    2014-01-01

    Chemical expansion refers to the spatial dilation of a material that occurs upon changes in its composition. When this dilation is caused by a gradual, iso-structural increase in the lattice parameter with composition, it is related to the composition change by the stoichiometric expansion coeffi...

  16. A chemically-defined protocol for generating chondrocytes from human embryonic stem cells

    OpenAIRE

    sprotocols

    2015-01-01

    Progress in generating robust differentiation protocols for efficient and scalable production of defined cell lineages from human embryonic stem cells (hESc) has been slow. Amongst the obstacles to be addressed are those inherent to standard hESc culture and differentiation practices including the use of feeder cells, serum and animal-derived matrices. These components are biologically complex, undefined and highly variable between batches, inhibiting the development of consistently reproduci...

  17. Substitution of Hospital Care with Primary Care: Defining the Conditions of Primary Care Plus

    OpenAIRE

    van Hoof, Sofie Johanna Maria; Kroese, Mariëlle Elisabeth Aafje Lydia; Spreeuwenberg, Marieke Dingena; Elissen, Arianne Mathilda Josephus; Meerlo, Ronald Johan; Hanraets, Monique Margaretha Henriëtte; Ruwaard, Dirk

    2016-01-01

    Objective: To analyse barriers and facilitators in substituting hospital care with primary care to define preconditions for successful implementation.Methods: A descriptive feasibility study was performed to collect information on the feasibility of substituting hospital care with primary care. General practitioners were able to refer patients, about whom they had doubts regarding diagnosis, treatment and/or the need to refer to hospital care, to medical specialists who performed low-complex ...

  18. Effects of selenium, calcium and calcium ionophore on human oocytes in vitro maturation in a chemically defined medium

    OpenAIRE

    Hessam Roustaei; Mohammad Hasan Fallahian; Fatemeh Peyghambari; Raheleh Aram; Mohammad Ali Sabbaghi; Elham Saboori; Mehri Makki; Abbas Ahmadi

    2012-01-01

    Background: In vitro maturation (IVM) of human oocytes is an emerging procedure quickly incorporated into the world of assisted reproductive technologies. As an effective method of in vitro maturation, several studies have reported the critical role of differentions on activating the complex process involved in both gamete maturation and fertilization. Objective: In this study, we supplemented a chemically defined medium with different combinations of selenium, calcium and calcium ionophore c...

  19. A chemical tool box defines mitotic and interphase roles for Mps1 kinase

    OpenAIRE

    Lan, Weijie; Don W Cleveland

    2010-01-01

    In this issue, three groups (Hewitt et al. 2010. J. Cell Biol. doi:10.1083/jcb.201002133; Maciejowski et al. 2010. J. Cell Biol. doi:10.1083/jcb.201001050; Santaguida et al. 2010. J. Cell Biol. doi:10.1083/jcb.201001036) use chemical inhibitors to analyze the function of the mitotic checkpoint kinase Mps1. These studies demonstrate that Mps1 kinase activity ensures accurate chromosome segregation through its recruitment to kinetochores of mitotic checkpoint proteins, formation of interphase a...

  20. Fate of hydraulic fracturing chemicals under down-hole conditions

    Science.gov (United States)

    Blotevogel, J.; Kahrilas, G.; Corrin, E. R.; Borch, T.

    2013-12-01

    Hydraulic fracturing is a method to increase the yield of oil and natural gas extraction from unconventional rock formations. The process of hydrofracturing occurs via injecting water, sand, and chemicals into the production well and subjecting this mixture to high pressures to crack the rock shale, allowing increased amounts of gas and oil to seep out of the target formation. Typical constituents of the chemical mixtures are biocides, which are applied to inhibit growth of sulfate reducing bacteria in order to prevent pipe corrosion and production of hazardous gases. However, very little is known about the persistence, fate, and activity of biocides when subjected to the high temperatures and pressures of down-hole conditions. Thus, the objective of this talk is to present data from ongoing experiments focused on determining the fate of biocides commonly used for hydraulic fracturing under conditions simulating down-hole environments. Using stainless steel reactors, the high pressures and temperatures of down-hole conditions in the Marcellus shale are simulated, while concentration, speciation, and degradation of priority biocides are observed as a function of time, using primarily LC/MS techniques. The impact of water quality, shale, temperature, and pressure on the transformation kinetics and pathways of biocides will be discussed. Finally, field samples (both sediments and flowback brine) from the Marcellus shale are analyzed to verify that our lab simulations mirror real-life conditions and results.

  1. Contributions to the chemical behavior of radionuclides conditioned by cement

    International Nuclear Information System (INIS)

    Leaching behavior of conditioned 137Cs, 90Sr and 57Co in different cement composites has been investigated. Cement, mortar and concrete of different compositions and preparation procedures was used as binding matrix. Long-term leaching tests at 18, 51 and 800C temperature were performed. Compression strengths were also determined. Accident conditions were simulated by crushing the cylindrical samples. Under the experimental conditions Co proved to be non leachable and Cs more leachable than Sr. No correlation was found between the strength and leaching rates. Therefore in designing binding matrices as a primary barrier optimization of the retaining properties should be the primary goal whereas increasing mechanical strength should be shifted to other parts (containment etc.). Moreover a suitable chemical composition should take care that the pH-value of an ingressing liquid should be changed towards smaller corrosivity. (G.Q.)

  2. Defined PEG smears as an alternative approach to enhance the search for crystallization conditions and crystal-quality improvement in reduced screens

    Energy Technology Data Exchange (ETDEWEB)

    Chaikuad, Apirat, E-mail: apirat.chaikuad@sgc.ox.ac.uk [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom); Knapp, Stefan [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom); Johann Wolfgang Goethe-University, Building N240 Room 3.03, Max-von-Laue-Strasse 9, 60438 Frankfurt am Main (Germany); Delft, Frank von, E-mail: apirat.chaikuad@sgc.ox.ac.uk [University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Headington, Oxford OX3 7DQ (United Kingdom)

    2015-07-28

    An alternative strategy for PEG sampling is suggested through the use of four newly defined PEG smears to enhance chemical space in reduced screens with a benefit towards protein crystallization. The quest for an optimal limited set of effective crystallization conditions remains a challenge in macromolecular crystallography, an issue that is complicated by the large number of chemicals which have been deemed to be suitable for promoting crystal growth. The lack of rational approaches towards the selection of successful chemical space and representative combinations has led to significant overlapping conditions, which are currently present in a multitude of commercially available crystallization screens. Here, an alternative approach to the sampling of widely used PEG precipitants is suggested through the use of PEG smears, which are mixtures of different PEGs with a requirement of either neutral or cooperatively positive effects of each component on crystal growth. Four newly defined smears were classified by molecular-weight groups and enabled the preservation of specific properties related to different polymer sizes. These smears not only allowed a wide coverage of properties of these polymers, but also reduced PEG variables, enabling greater sampling of other parameters such as buffers and additives. The efficiency of the smear-based screens was evaluated on more than 220 diverse recombinant human proteins, which overall revealed a good initial crystallization success rate of nearly 50%. In addition, in several cases successful crystallizations were only obtained using PEG smears, while various commercial screens failed to yield crystals. The defined smears therefore offer an alternative approach towards PEG sampling, which will benefit the design of crystallization screens sampling a wide chemical space of this key precipitant.

  3. Defined PEG smears as an alternative approach to enhance the search for crystallization conditions and crystal-quality improvement in reduced screens.

    Science.gov (United States)

    Chaikuad, Apirat; Knapp, Stefan; von Delft, Frank

    2015-08-01

    The quest for an optimal limited set of effective crystallization conditions remains a challenge in macromolecular crystallography, an issue that is complicated by the large number of chemicals which have been deemed to be suitable for promoting crystal growth. The lack of rational approaches towards the selection of successful chemical space and representative combinations has led to significant overlapping conditions, which are currently present in a multitude of commercially available crystallization screens. Here, an alternative approach to the sampling of widely used PEG precipitants is suggested through the use of PEG smears, which are mixtures of different PEGs with a requirement of either neutral or cooperatively positive effects of each component on crystal growth. Four newly defined smears were classified by molecular-weight groups and enabled the preservation of specific properties related to different polymer sizes. These smears not only allowed a wide coverage of properties of these polymers, but also reduced PEG variables, enabling greater sampling of other parameters such as buffers and additives. The efficiency of the smear-based screens was evaluated on more than 220 diverse recombinant human proteins, which overall revealed a good initial crystallization success rate of nearly 50%. In addition, in several cases successful crystallizations were only obtained using PEG smears, while various commercial screens failed to yield crystals. The defined smears therefore offer an alternative approach towards PEG sampling, which will benefit the design of crystallization screens sampling a wide chemical space of this key precipitant. PMID:26249344

  4. Does phosphate enhance the natural attenuation of crude oil in groundwater under defined redox conditions?

    Science.gov (United States)

    Ponsin, Violaine; Mouloubou, Olsen Raïnness; Prudent, Pascale; Höhener, Patrick

    2014-11-01

    After a crude oil spill caused by a broken pipeline in 2009 to a gravel aquifer in southern France, degradation processes under various redox conditions progressively established, but at rates that predict a long life-time of the source under natural attenuation after partial source removal. In this study, we aimed at identifying the rate-limiting factors for each redox condition, with special emphasis on phosphate as limiting nutrient. The study was conducted in laboratory microcosms assembled with material collected on site: sediments, water from monitoring wells, oil and microbial sludge. Redox conditions were promoted by adding electron acceptors (either oxygen, nitrate, limonite (FeO(OH)), cryptomelane (K(Mn4 +,Mn2 +)8O16), or sulfate). For each condition, the role of phosphate was studied by repeated additions for up to 290 days. The results showed a very strong stimulation of aerobic and denitrifying rates of oil degradation by phosphate, provided that oxygen and nitrate were repeatedly supplied. Phosphate caused also a marked stimulation of methanogenic degradation, and a relatively small stimulation of metal reduction. These anaerobic processes started only after marked lag phases, and phosphate shortened the lag phase for methanogenic degradation. Degradation of aromatic and aliphatic hydrocarbons with less than 8 carbons, including benzene, was confirmed even under unstimulated conditions. It is concluded that degradation rates at the site are limited by both, availability of electron acceptors and availability of phosphate needed for promoting microbial growth.

  5. Physico-chemical gradients within the hydrothermal chimney Roane define sharp boundaries for microbial community ecology

    Science.gov (United States)

    Frank, K. L.; Kelley, D. S.; Girguis, P. R.

    2011-12-01

    The unique physico-chemical gradients characteristic of hydrothermal vents provide diverse niches for prokaryotic communities. To date, our knowledge of environmental constraints on microbial colonization and metabolic activity within active sulfide structures has been limited by the lack of co-registered in situ chemistry and appropriate, taxonomic and metabolic genetic markers. Here we characterize de novo endolithic microbial colonization using a sulfide microbial incubator within the hydrothermal vent Roane during a one-year deployment, with co-registered temperature, fluid chemistry and mineralogy. Taxanomic assessment of phylogenetic diversity via 16S rDNA extracted from the outer (40-70°C) and middle (150-240°C) chambers of the incubator revealed patterns of distribution comparable to previously published observations. However, quantitative and statistical analyses of 16S rDNA sequences from two chambers revealed very distinct communities, with less than 5% of the identified operational taxonomic units common to both chambers. Analyses of metagenomic data suggest an elevated potential for motility and select biosynthetic pathways in the outer chamber community. In contrast, the middle chamber community exhibits a greater potential for quorum sensing, biofilm formation and archaeal lipid biosynthesis. Striking differences in metabolic potential were also apparent. These data suggest that the distribution, abundance and physiological capacity of these communities is strongly governed by chemical and physical variability of the environment.

  6. Defining and Identifying Hard-to-Staff Schools: The Role of School Demographics and Conditions

    Science.gov (United States)

    Opfer, Darleen

    2011-01-01

    Purpose: This study makes a distinction between a school having high attrition and one having difficulties in hiring. It does so by exploring the relationship between definitions of hard-to-staff schools, school demographics, and school conditions that are often associated with a school being hard-to-staff. Research Design: The study relies on a…

  7. Chemical durability of copper canisters under crystalline bedrock repository conditions

    International Nuclear Information System (INIS)

    In the Swedish waste management program, the copper canister is expected to provide containment of the radionuclides for a very long time, perhaps millions of years. The purpose of the present paper, is to analyze prerequisites for assessments of corrosion lifetimes for copper canisters. The analysis is based on compilations of literature from the following areas: chemical literature on copper and copper corrosion, mineralogical literature with emphasis on the stability of copper in near surface environments, and chemical and mineralogical literature with emphasis on the stabilities and thermodynamics of species and phases that may exist in a repository environment. Three main types of situations are identified: (1) under oxidizing and low chloride conditions, passivating oxide type of layers may form on the copper surface; (2) under oxidizing and high chloride conditions, the species formed may all be dissolved; and (3) under reducing conditions, non-passivating sulfide type layer may form on the copper surface. Considerable variability and uncertainty exists regarding the chemical environment for the canister, especially in certain scenarios. Thus, the mechanisms for corrosion can be expected to differ greatly for different situations. The lifetime of a thick-walled copper canister subjected to general corrosion appears to be long for most reasonable chemistries. (It is assumed that the canister has no defects from manufacturing and that the bentonite buffer is intact). Localized corrosion may appear for types (1) and (3) above but the mechanisms are widely different in character. The penetration caused by localized corrosion can be expected to be very sensitive to details in the chemistry

  8. Improving Productivity by Deriving and Defining Target Conditions in the Value Stream of Packing

    OpenAIRE

    Sunk, Alexander; Sihn, Wilfried; Kuhlang, Peter

    2015-01-01

    In the entire value stream of original spare part supply, packing is one of the main issues in the distribution system and its productivity is mainly affected by a particularly high proportion of manual work. This paper presents an approach to support practical work improvements in value streams generally, and from the theoretical and the practical point of view it shows how performance enhancing and learning enhancing target conditions or standards – e.g. for the working method – can be deri...

  9. Defining and applying the steam path dynamic load for nuclear power up rate conditions

    International Nuclear Information System (INIS)

    Less than 6 months after performing a 15% power up rate, Quad Cities Unit 2 experienced significant steam dryer degradation the required the unit to be shut down. Investigations revealed that the steam dryer front hood made of 1/4 stainless steel plate had fatigued and detached from the dryer and portions of the detached 1/4 plate entered the main steam lines. Quad Cities Nuclear plant is a two unit Boiling Water Reactor (BWR/3). The only design requirement for the BWR steam dryer is to stay intact during normal and emergency operating conditions. As a result there was no requirement to instrument the dryer or perform a detailed pressure oscillation load evaluation for power up rate conditions. While BWRs have experienced steam dryer degradation in the past, efforts to understand the root cause have never been totally successful. Based on the significance of the dryer degradation Ex elon, embarked on a 'first of a kind' steam path instrumentation and analytical dynamic load definition methodology that could be applied to 3 dimensional finite element analysis of the dryer component and resolve the root cause of the dryer degradation. This analytical dynamic load definition approach was benchmarked against in vessel pressure gauge mounted directly on the steam dryer and found to have an uncertainty of less than 6.5%. Using this benchmark load definition, Ex elon was able to validate that the dryer structure is acceptable for up-rated conditions with a 3 dimensional finite element model and analysis

  10. Chemical and isotopic study to define the origin of acidity in the Los Humeros geothermal reservoir

    International Nuclear Information System (INIS)

    Chemical and isotopic analyses of geothermal fluids were carried out at the Los Humeros, Mexico, geothermal field in order to establish the water-rock equilibrium state and to determine the origin of the acidity in the reservoir. From the perspective of water-rock equilibrium, the Los Humeros geothermal reservoir is out of equilibrium. This is probably the case since it is associated with recent volcanism, with magmatic components in the geothermal fluids that are not neutralized by reaction with feldspar and mica. Superheated magmatic steam contains HCl gas, which condenses or mixes with liquid at moderate temperature (2/Ar of 270 to 340 deg. C. The isotopic composition of the Los Humeros wells shows anδ18O shift which is characteristic of fluids of geothermal origin that have reached equilibrium with the rock at high temperatures. The isotopic compositions of cold spring waters in the area are mostly located on the meteoric line. The sample from Alchichica lagoon has an isotopic composition typical of evaporated water. (author)

  11. Texture-defined objects influence responses of blowfly motion-sensitive neurons under natural dynamical conditions

    Directory of Open Access Journals (Sweden)

    Thomas W. Ullrich

    2014-04-01

    Full Text Available The responses of visual interneurons of flies involved in the processing of motion information do not only depend on the velocity, but also on other stimulus parameters, such as the contrast and the spatial frequency content of the stimulus pattern. These dependencies have been known for long, but it is still an open question how they affect the neurons’ performance in extracting information about the structure of the environment under the specific dynamical conditions of natural flight. Free-flight of blowflies is characterized by sequences of phases of translational movements lasting for just 30-100 milliseconds interspersed with even shorter and extremely rapid saccade-like rotational shifts in flight and gaze direction. Previous studies already analyzed how nearby objects, leading to relative motion on the retina with respect to a more distant background, influenced the response of a class of fly motion sensitive visual interneurons, the HS cells. In the present study, we focused on objects that differed from their background by discontinuities either in their brightness contrast or in their spatial frequency content. We found strong object-induced effects on the membrane potential even during the short intersaccadic intervals, if the background contrast was small and the object contrast sufficiently high. The object evoked similar response increments provided that it contained higher spatial frequencies than the background, but not under reversed conditions. This asymmetry in the response behavior is partly a consequence of the depolarization level induced by the background. Thus, our results suggest that, under the specific dynamical conditions of natural flight, i.e. on a very short timescale, the responses of HS cells represent object information depending on the polarity of the difference between object and background contrast and spatial frequency content.

  12. Defining BMP functions in the hair follicle by conditional ablation of BMP receptor IA

    OpenAIRE

    Kobielak, Krzysztof; Pasolli, H. Amalia; Alonso, Laura; Polak, Lisa; Fuchs, Elaine

    2003-01-01

    Using conditional gene targeting in mice, we show that BMP receptor IA is essential for the differentiation of progenitor cells of the inner root sheath and hair shaft. Without BMPRIA activation, GATA-3 is down-regulated and its regulated control of IRS differentiation is compromised. In contrast, Lef1 is up-regulated, but its regulated control of hair differentiation is still blocked, and BMPRIA-null follicles fail to activate Lef1/β-catenin–regulated genes, including keratin genes. Wnt-medi...

  13. A Molecular and Chemical Perspective in Defining Melatonin Receptor Subtype Selectivity

    Directory of Open Access Journals (Sweden)

    Yung Hou Wong

    2013-09-01

    Full Text Available Melatonin is primarily synthesized and secreted by the pineal gland during darkness in a normal diurnal cycle. In addition to its intrinsic antioxidant property, the neurohormone has renowned regulatory roles in the control of circadian rhythm and exerts its physiological actions primarily by interacting with the G protein-coupled MT1 and MT2 transmembrane receptors. The two melatonin receptor subtypes display identical ligand binding characteristics and mediate a myriad of signaling pathways, including adenylyl cyclase inhibition, phospholipase C stimulation and the regulation of other effector molecules. Both MT1 and MT2 receptors are widely expressed in the central nervous system as well as many peripheral tissues, but each receptor subtype can be linked to specific functional responses at the target tissue. Given the broad therapeutic implications of melatonin receptors in chronobiology, immunomodulation, endocrine regulation, reproductive functions and cancer development, drug discovery and development programs have been directed at identifying chemical molecules that bind to the two melatonin receptor subtypes. However, all of the melatoninergics in the market act on both subtypes of melatonin receptors without significant selectivity. To facilitate the design and development of novel therapeutic agents, it is necessary to understand the intrinsic differences between MT1 and MT2 that determine ligand binding, functional efficacy, and signaling specificity. This review summarizes our current knowledge in differentiating MT1 and MT2 receptors and their signaling capacities. The use of homology modeling in the mapping of the ligand-binding pocket will be described. Identification of conserved and distinct residues will be tremendously useful in the design of highly selective ligands.

  14. Delineation of the southern elephant seal's main foraging environments defined by temperature and light conditions

    Science.gov (United States)

    Vacquié-Garcia, Jade; Guinet, Christophe; Laurent, Cécile; Bailleul, Frédéric

    2015-03-01

    Changes in marine environments, induced by the global warming, are likely to influence the prey field distribution and consequently the foraging behaviour and the distribution of top marine predators. Thanks to bio-logging, the simultaneous measurements of fine-scale foraging behaviors and oceanographic parameters by predators allow characterizing their foraging environments and provide insights into their prey distribution. In this context, we propose to delimit and to characterize the foraging environments of a marine predator, the Southern Elephant Seal (SES). To do so, the relationship between oceanographic factors and prey encounter events (PEE) was investigated in 12 females SES from Kerguelen Island simultaneously equipped with accelerometers and with a range of physical sensors (temperature, light and depth). PEEs were assessed from the accelerometer data at high spatio-temporal precision while the physical sensors allowed the continuous monitoring of environmental conditions encountered by the SES when diving. First, visited and foraging environments were distinguished according to the oceanographic conditions encountered in the absence and in presence of PEE. Then, a hierarchical classification of the physical parameters recorded during PEEs led to the distinction of five different foraging environments. These foraging environments were structured according to the main frontal systems of the SO. One was located north to the subantarctic front (SAF) and characterized by high temperature and depth, and low light levels. Another, characterized by intermediate levels of temperature, light and depth, was located between the SAF and the polar front (PF). And finally, the last three environments were all found south to the PF and, characterized by low temperature but highly variable depth and light levels. The large physical and/or spatial differences found between these environments suggest that, depending on the location, different prey communities are

  15. Effect of glucose and pyruvate on nuclear and cytoplasmic maturation of porcine oocytes in a chemically defined medium

    OpenAIRE

    FUNAHASHI, Hiroaki; Koike, Takayuki; Sakai, Ryoko

    2008-01-01

    The objective was to examine potential roles of glucose and pyruvate in nuclear and cytoplasmic maturation of porcine oocytes. Oocyte-cumulus complexes (OCC), derived from 3 to 6 mm follicles, were cultured in a chemically defined medium (pyruvate-free mNCSU37-PVA), with or without 5.55 mM glucose, during in vitro maturation (IVM); in the absence of glucose, germinal vesicle breakdown (GVBD) and nuclear maturation were prevented (P < 0.05). Subsequently, OCC were cultured for IVM in glucose-c...

  16. Feline Neural Progenitor Cells I: Long-Term Expansion under Defined Culture Conditions

    Directory of Open Access Journals (Sweden)

    Jing Yang

    2012-01-01

    Full Text Available Neural progenitor cells (NPCs of feline origin (cNPCs have demonstrated utility in transplantation experiments, yet are difficult to grow in culture beyond the 1 month time frame. Here we use an enriched, serum-free base medium (Ultraculture and report the successful long-term propagation of these cells. Primary cultures were derived from fetal brain tissue and passaged in DMEM/F12-based or Ultraculture-based proliferation media, both in the presence of EGF + bFGF. Cells in standard DMEM/F12-based medium ceased to proliferate by 1-month, whereas the cells in the Ultraculture-based medium continued to grow for at least 5 months (end of study with no evidence of senescence. The Ultraculture-based cultures expressed lower levels of progenitor and lineage-associated markers under proliferation conditions but retained multipotency as evidenced by the ability to differentiate into neurons and glia following growth factor removal in the presence of FBS. Importantly, later passage cNPCs did not develop chromosomal aberrations.

  17. Chemical flowsheet conditions for preparing urania spheres by internal gelation

    International Nuclear Information System (INIS)

    Small, ceramic urania spheres can be prepared for use as nuclear fuel by internal chemical gelation of uranyl nitrate solution droplets. Acid-deficient uranyl nitrate solutions up to 3.4 M in uranium with NO3-U mole ratios of 1.5 to 1.7 are prepared by dissolution of U3O8 or UO3. Decomposition of hexamethylenetetramine dissolved in the uranyl nitrate solution releases ammonia to precipitate hydrated UO/sub 3/. Previously established flowsheet conditions have been improved and modified at ORNL and have been applied to prepare dense UO2 spheres with average diameters of 1200, 300, and 30 μm. The 1200- and 300-μm UO2 spheres were prepared by gelation in trichloroethylene at 50 to 650C; 2-ethyl-1-hexanol was used as the gelation medium to prepare 30-μm UO2 spheres. 8 refs

  18. Effect of commercially available chemically defined liquid diets on the intestinal microflora and bacterial translocation from the gut.

    Science.gov (United States)

    Alverdy, J C; Aoys, E; Moss, G S

    1990-01-01

    The effect of chemically defined liquid diets on the intestinal microflora and bacterial translocation from the gut was studied in the rat. Seventy-five female Fischer rats were randomized to five groups of 15 animals each. Group I was fed rat chow and water, group II was fed Vivonex TEN, group III was fed Ensure, group IV was fed Enrich, and group V was fed Ensure plus ground corn cobs, a crude fiber source. Animals were fed their respective diets ad libitum for 1 week and then killed. Quantitative culture of the mesenteric lymph nodes (MLN) and cecum was performed to determine bacterial translocation from the gut. A 66% translocation rate (10/15) of bacteria to MLN was observed in the animals fed Ensure and Enrich compared to 21% in the Vivonex TEN group (3/14) and 20% in the animals fed Ensure plus ground corn cobs (3/15). None of the animals in the control group eating their normal diets of rat chow and water developed positive MLN. Statistical significance (p less than 0.001) was achieved between the Ensure and Enrich groups when compared to controls but not between the Vivonex TEN and Ensure plus corn cobs. Cecal culture revealed a statistically significant rise in cecal bacteria in all groups when compared to the control group (group I). These results indicate that chemically defined liquid diets result in altered intestinal microflora and bacterial translocation from the gut. PMID:2325237

  19. Protein folding: Defining a standard set of experimental conditions and a preliminary kinetic data set of two-state proteins

    DEFF Research Database (Denmark)

    Maxwell, Karen L.; Wildes, D.; Zarrine-Afsar, A.;

    2005-01-01

    rates, thermodynamics, and structure across diverse sets of proteins. These difficulties include the wide, potentially confounding range of experimental conditions and methods employed to date and the difficulty of obtaining correct and complete sequence and structural details for the characterized...... constructs. The lack of a single approach to data analysis and error estimation, or even of a common set of units and reporting standards, further hinders comparative studies of folding. In an effort to overcome these problems, we define here a consensus set of experimental conditions (25°C at pH 7.0, 50 m......M buffer), data analysis methods, and data reporting standards that we hope will provide a benchmark for experimental studies. We take the first step in this initiative by describing the folding kinetics of 30 apparently two-state proteins or protein domains under the consensus conditions. The goal of our...

  20. Effectiveness of chemical dispersants under breaking wave conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mackay, D. [Univ. of Toronto, Ontario (Canada). Chemical Engineering Dept.

    1995-06-01

    A study is described in which the effectiveness of Corexit 9527 on Alaskan North Slope crude oil was assessed by conducting laboratory and wave basin tests. Three laboratory dispersant test systems were used: the MNS, Labofina and EXDET procedures. It was concluded that for the present purposes the EXDET system was most suitable, and it was used for subsequent tests. The dependence of effectiveness on dispersant to oil ratio, extent of weathering, temperature, water salinity, energy level and the presence of emulsified water (mousse) were determined. The results were used to guide a subsequent program of tests at the Esso Resources Canada Ltd. Wave Basin in Calgary in which the effectiveness was determined under breaking wave conditions. From the results a correlating equation was developed to express effectiveness as a function of dispersant to oil ratio and delay time between dispersant application and the onset of breaking waves. Significant quantities of oil were dispersed under breaking wave conditions, even at what are conventionally regarded as low dispersant to oil ratios. The implications of the results for assessing the actual and potential extent of chemical dispersion following the Exxon Valdez spill in March 1989 are discussed. Assuming that the dispersion efficiencies from the wave basin could have been achieved at the incident, it is believed that because of the onset of the storm with breaking wave conditions some 60 hours after the grounding, approximately 38% of the spilled oil could have been dispersed had available dispersants been applied to the spilled oil in the days following the grounding.

  1. Variable impact on mortality of AIDS-defining events diagnosed during combination antiretroviral therapy : not all AIDS-defining conditions are created equal

    NARCIS (Netherlands)

    Mocroft, Amanda; Sterne, Jonathan A C; Egger, Matthias; May, Margaret; Grabar, Sophie; Furrer, Hansjakob; Sabin, Caroline; Fatkenheuer, Gerd; Justice, Amy; Reiss, Peter; d'Arminio Monforte, Antonella; Gill, John; Hogg, Robert; Bonnet, Fabrice; Kitahata, Mari; Staszewski, Schlomo; Casabona, Jordi; Harris, Ross; Saag, Michael; Niesters, Bert

    2009-01-01

    BACKGROUND: The extent to which mortality differs following individual acquired immunodeficiency syndrome (AIDS)-defining events (ADEs) has not been assessed among patients initiating combination antiretroviral therapy. METHODS: We analyzed data from 31,620 patients with no prior ADEs who started co

  2. Culture of human pluripotent stem cells using completely defined conditions on a recombinant E-cadherin substratum

    Directory of Open Access Journals (Sweden)

    Duncan Stephen A

    2010-06-01

    Full Text Available Abstract Background To maintain pluripotency of human embryonic stem (huES cells in feeder-free culture it has been necessary to provide a Matrigel substratum, which is a complex of poorly defined extracellular matrices and growth factors derived from mouse Engelbreth-Holm-Swarm sarcoma cells. Culture of stem cells under ill-defined conditions can inhibit the effectiveness of maintaining cells in a pluripotent state and reduce reproducibility of differentiation protocols. Moreover recent batches of Matrigel have been found to be contaminated with the single stranded RNA virus, Lactate Dehydrogenase Elevating Virus (LDEV, raising concerns regarding the safety of using stem cells that have been cultured on Matrigel in a therapeutic setting. To circumvent such concerns, we attempted to identify a recombinant matrix that could be used as an alternative to Matrigel for the culture of human pluripotent stem cells. huES and human induced pluripotent stem (hiPS cells were grown on plates coated with a fusion protein consisting of E-cadherin and the IgG Fc domain using mTeSR1 medium. Results Cells grown under these conditions maintained similar morphology and growth rate to those grown on Matrigel and retained all pluripotent stem cell features, including an ability to differentiate into multiple cell lineages in teratoma assays. We, therefore, present a culture system that maintains the pluripotency of huES and hiPS cells under completely defined conditions. Conclusions We propose that this system should facilitate growth of stem cells using good manufacturing practices (GMP, which will be necessary for the clinical use of pluripotent stem cells and their derivatives.

  3. Chemical extraction of arsenic from contaminated soil under subcritical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Seok-Young, E-mail: quartzoh@ulsan.ac.kr [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680 749 (Korea, Republic of); Yoon, Myong-Keun; Kim, Ick-Hyun [Department of Civil and Environmental Engineering, University of Ulsan, Ulsan 680 749 (Korea, Republic of); Kim, Ju Yup; Bae, Wookeun [Department of Civil and Environmental Engineering, Hanyang University, Gyunggi-Do 425 791 (Korea, Republic of)

    2011-07-15

    In this research, we investigated a chemical extraction process, under subcritical conditions, for arsenic (As)-contaminated soil in the vicinity of an abandoned smelting plant in South Korea. The total concentration of As in soil was 75.5 mg/kg, 68% of which was As(+ III). X-ray photoelectron spectroscopy analysis showed that the possible As(+ III)-bearing compounds in the soil were As{sub 2}O{sub 3} and R-AsOOH. At 20 {sup o}C, 100 mM of NaOH could extract 26% of the As from the soil samples. In contrast, 100 mM of ethylenediaminetetraacetic acid (EDTA) and citric acid showed less than 10% extraction efficiency. However, as the temperature increased to 250 and 300 {sup o}C, extraction efficiencies increased to 75-91% and 94-103%, respectively, regardless of the extraction reagent used. Control experiments with subcritical water at 300 {sup o}C showed complete extraction of As from the soil. Arsenic species in the solution extracted at 300 {sup o}C indicated that subcritical water oxidation may be involved in the dissolution of As(+ III)-bearing minerals under given conditions. Our results suggest that subcritical water extraction/oxidation is a promising option for effective disposal of As-contaminated soil. - Research highlights: {yields} Extraction efficiency by EDTA, citric acid, and NaOH is limited at room temperature. {yields} Extraction efficiencies increase to 94-103% at 300 {sup o}C regardless of the extraction reagent used. {yields} Subcritical water oxidation may be responsible for the dissolution of As(+ III)-bearing minerals.

  4. Modelling long-term chemical degradation of a concrete container under near surface disposal conditions

    International Nuclear Information System (INIS)

    The paper presents an application of a simplified 2D model of chemical degradation for a cracked concrete container termed monolith under near surface disposal conditions. The objective is to gain an improved understanding of the rate of degradation of the cracked monolith and its impact on transport of radionuclides under saturated conditions. Chemical degradation of concrete affects physical and mechanical properties and consequently accelerates migration of radionuclides from the cementitious engineered barriers. The abstracted large scale 2D model of chemical concrete degradation is based on a more detailed model from Jacques et al. (companion paper) who consider Ca leaching of CEM I concrete and consequent evolution of the physical properties such as porosity, bulk density, hydraulic conductivity, and tortuosity. Due to the uncertainty associated with the long term evolution of cracks in concrete, different crack networks have been postulated for different periods of time. The paper examines the effect of different crack densities, water boundary condition and magnitude of hydraulic conductivity on the degradation evolution of the monolith and release of radionuclides from conditioned waste grouted in the monolith. It is concluded that, for the postulated crack network and the transport mode defined by the flow boundary condition, the impact of crack density on the degradation rate and radionuclide leaching was minimal. The impact of the type of transport regime (advective and diffusive) and the magnitude of saturated hydraulic conductivity on the transport were significant. Several simplifications were made in the analyses (e.g. no sorption and decay); however, those could be easily relaxed within the proposed modelling framework. However, further investigations are ongoing to address the impact and sensitivity of additional complexities. (authors)

  5. Organic chemical degradation by remote study of the redox conditions

    Science.gov (United States)

    Fernandez, P. M.; Revil, A.; Binley, A. M.; Bloem, E.; French, H. K.

    2014-12-01

    Monitoring the natural (and enhanced) degradation of organic contaminants is essential for managing groundwater quality in many parts of the world. Contaminated sites often have limited access, hence non-intrusive methods for studying redox processes, which drive the degradation of organic compounds, are required. One example is the degradation of de-icing chemicals (glycols and organic salts) released to the soil near airport runways during winter. This issue has been broadly studied at Oslo airport, Gardermoen, Norway using intrusive and non-intrusive methods. Here, we report on laboratory experiments that aim to study the potential of using a self-potential, DCresistivity, and time-domain induced polarization for geochemical characterization of the degradation of Propylene Glycol (PG). PG is completely miscible in water, does not adsorb to soil particles and does not contribute to the electrical conductivity of the soil water. When the contaminant is in the unsaturated zone near the water table, the oxygen is quickly consumed and the gas exchange with the surface is insufficient to ensure aerobic degradation, which is faster than anaerobic degradation. Since biodegradation of PG is highly oxygen demanding, anaerobic pockets can exist causing iron and manganese reduction. It is hypothesised that nitrate would boost the degradation rate under such conditions. In our experiment, we study PG degradation in a sand tank. We provide the system with an electron highway to bridge zones with different redox potential. This geo-battery system is characterized by self-potential, resistivity and induced polarization anomalies. An example of preliminary results with self-potential at two different times of the experiment can be seen in the illustration. These will be supplemented with more direct information on the redox chemistry: in-situ water sampling, pH, redox potential and electrical conductivity measurements. In parallel, a series of batch experiments have been

  6. A chemically defined culture medium containing Rho kinase inhibitor Y-27632 for the fabrication of stratified squamous epithelial cell grafts

    Energy Technology Data Exchange (ETDEWEB)

    Aslanova, Afag [Department of Surgery, Institute of Gastroenterology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Institute of Advanced Biomedical Engineering and Science, Tokyo Women' s Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Takagi, Ryo; Yamato, Masayuki; Okano, Teruo [Institute of Advanced Biomedical Engineering and Science, Tokyo Women' s Medical University, TWIns, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan); Yamamoto, Masakazu, E-mail: yamamoto.ige@twmu.ac.jp [Department of Surgery, Institute of Gastroenterology, Tokyo Women' s Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo 162-8666 (Japan)

    2015-05-01

    With the development of a culture method for stratified squamous epithelial cells, tissue-engineered epithelial cell sheets have been successfully applied as clinical cell grafts. However, the implementation of these cell sheets without the use of any animal-derived materials is highly desirable. In this study, Rho-associated protein kinase inhibitor Y-27632 was used to develop a chemically defined culture medium for the fabrication of stratified epithelial cell grafts consisting of human epidermal and oral keratinocytes, and the proliferation activity, cell morphology, and gene expressions of the keratinocytes were analyzed. The results of a colorimetric assay indicated that Y-27632 significantly promoted the proliferation of the keratinocytes in culture media both with and without fetal bovine serum (FBS), although there were no indications of Y-27632 efficacy on cell morphology and stratification of the keratinocytes in culture medium without any animal-derived materials. The results of quantitative RT-PCR revealed that gene expressions correlated with cell adhesion, cell–cell junction, proliferation markers, and stem/progenitor markers in cultured keratinocytes were not strongly affected by the addition of Y-27632 to the culture medium. Moreover, gene expressions of differentiation markers in stratified keratinocytes cultured in medium without FBS were nearly identical to those of keratinocytes co-cultured with 3T3 feeder cells. Interestingly, the expressions of differentiation markers in cultured stratified keratinocytes were suppressed by FBS, whereas they were reconstructed by either co-culture of a 3T3 feeder layer or addition of Y-27632 into the culture medium containing FBS. These findings indicate that Y-27632 is a useful supplement for the development of a chemically defined culture medium for fabrication of stratified epithelial cell grafts for clinical applications for the purpose of developing the culture medium with a lower risk of pathogen

  7. A chemically defined culture medium containing Rho kinase inhibitor Y-27632 for the fabrication of stratified squamous epithelial cell grafts

    International Nuclear Information System (INIS)

    With the development of a culture method for stratified squamous epithelial cells, tissue-engineered epithelial cell sheets have been successfully applied as clinical cell grafts. However, the implementation of these cell sheets without the use of any animal-derived materials is highly desirable. In this study, Rho-associated protein kinase inhibitor Y-27632 was used to develop a chemically defined culture medium for the fabrication of stratified epithelial cell grafts consisting of human epidermal and oral keratinocytes, and the proliferation activity, cell morphology, and gene expressions of the keratinocytes were analyzed. The results of a colorimetric assay indicated that Y-27632 significantly promoted the proliferation of the keratinocytes in culture media both with and without fetal bovine serum (FBS), although there were no indications of Y-27632 efficacy on cell morphology and stratification of the keratinocytes in culture medium without any animal-derived materials. The results of quantitative RT-PCR revealed that gene expressions correlated with cell adhesion, cell–cell junction, proliferation markers, and stem/progenitor markers in cultured keratinocytes were not strongly affected by the addition of Y-27632 to the culture medium. Moreover, gene expressions of differentiation markers in stratified keratinocytes cultured in medium without FBS were nearly identical to those of keratinocytes co-cultured with 3T3 feeder cells. Interestingly, the expressions of differentiation markers in cultured stratified keratinocytes were suppressed by FBS, whereas they were reconstructed by either co-culture of a 3T3 feeder layer or addition of Y-27632 into the culture medium containing FBS. These findings indicate that Y-27632 is a useful supplement for the development of a chemically defined culture medium for fabrication of stratified epithelial cell grafts for clinical applications for the purpose of developing the culture medium with a lower risk of pathogen

  8. Growth enhancement of the halotolerant Brevibacterium sp. JCM 6894 by methionine externally added to a chemically defined medium.

    Science.gov (United States)

    Mimura, Haruo

    2014-01-01

    We examined amino acid requirements for the growth of the halotolerant Brevibacterium sp. JCM 6894 in the absence and presence of 1.2 M NaCl in a chemically defined medium. The experiment was also carried out in the presence of 1.2 M KCl. As a result, growth was highly enhanced by methionine in the absence and presence of KCl as well as NaCl up to 1.2 M. However, growth in the presence of 150 mM methionine was repressed by leucine (up to 100 mM)and valine (up to 100 mM). Concentration-dependent growth inhibition was observed in the presence of isoleucine (up to 150 mM) and threonine (up to 300 mM). When the cells were incubated in the absence of externally added K+, growth was strongly repressed, even in the presence of 150 mM methionine. The growth, however, recovered drastically by the addition of 1 mM KCl, regardless of the presence and absence of 1.2 M NaCl. These results indicate that methionine, which seems to be symported into cytoplasm with K+, plays an important role in the growth of the strain under salt stress. PMID:25252648

  9. A numerical solution to define channel heads and hillslope parameters from digital topography of glacially conditioned catchments

    Science.gov (United States)

    Salcher, Bernhard; Baumann, Sebastian; Kober, Florian; Robl, Jörg; Heiniger, Lukas

    2016-04-01

    The analysis of the slope-area relationship in bedrock streams is a common way for discriminating the channel from the hillslope domain and associated landscape processes. Spatial variations of these domains are important indicators of landscape change. In fluvial catchments, this relationship is a function of contributing drainage area, channel slope and the threshold drainage area for fluvial erosion. The resulting pattern is related to climate, tectonic and underlying bedrock. These factors may become secondary in catchments affected by glacial erosion, as it is the case in many mid- to high-latitude mountain belts. The perturbation (i.e. the destruction) of an initial steady state fluvial bedrock morphology (where uplift is balanced by surface lowering rates) will tend to become successively larger if the repeated action of glacial processes exceeds the potential of fluvial readjustment during deglaciated periods. Topographic change is associated with a decrease and fragmentation of the channel network and an extension of the hillslope domain. In case of glacially conditioned catchments discrimination of the two domains remains problematic and a discrimination inconsistent. A definition is therefore highly needed considering that (i) a spatial shift in the domains affect the process and rate of erosion and (ii) topographic classifications of alpine catchments often base on channel and hillslope parameters (i.e.channel or hillslope relief). Here we propose a novel numerical approach to topographically define channel heads from digital topography in glacially conditioned mountain range catchments in order to discriminate the channel from the hillslope domain. We analyzed the topography of the southern European Central Alps, a region which (i) has been glaciated multiple times during the Quaternary, shows (ii) little lithological variations, is (iii) home of very low erodible rocks and is (iv) known as a region were tectonic processes have largely ceased. The

  10. Chemical Enrichment and Physical Conditions in IZw18*

    Science.gov (United States)

    Lebouteiller, V.; Heap, S.; Hubeny, I.; Kunth, D.

    2013-01-01

    Low-metallicity star-forming dwarf galaxies are prime targets to understand the chemical enrichment of the interstellar medium. The H I region contains the bulk of the mass in blue compact dwarfs, and it provides important constraints on the dispersal and mixing of heavy elements released by successive star-formation episodes. The metallicity of the H I region is also a critical parameter to investigate the future star-formation history, as metals provide most of the gas cooling that will facilitate and sustain star formation. Aims. Our primary objective is to study the enrichment of the H I region and the interplay between star-formation history and metallicity evolution. Our secondary obje ctive is to constrain the spatial- and time-scales over which the HI and H II regions are enriched, and the mass range of stars responsible for the heavy element production. Finally, we aim to examine the gas heating and cooling mechanisms in the H I region. Methods. We observed the most metal-poor star-forming galaxy in the Local Universe, I Zw 18, with the Cosmic Origin Spectrograph onboard Hubble. The abundances in the neutral gas are derived from far-ultraviolet absorption-lines (H I, CIII, CIIi*, N I, OI,...) and are compared to the abundances in the H II region. Models are constructed to calculate the ionization structure and the thermal processes. We investigate the gas cooling in the HIi region through physical diagnostics drawn from the fine-structure level of C+. Results. We find that H I region abundances are lower by a factor of approx 2 as compared to the H II region. There is no differential depletion on dust between the H I and H II region. Using sulfur as a metallicity tracer, we calculate a metallicity of 1/46 Z(solar) (vs. 1/31 Z(solar) in the H II region). From the study of the C/O, [O/Fe], and N/O abundance ratios, we propose that C, N, O, and Fe are mainly produced in massive stars. We argue that the H I envelope may contain pockets of pristine gas with a

  11. Public Health Risk Conditioned by Chemical Composition of Ground Water

    Science.gov (United States)

    Yankovich, E.; Osipova, N.; Yankovich, K.; Matveenko, I.

    2016-03-01

    The article studies the public health potential risk originated from water consumption and estimated on the basis of the groundwater chemical composition. We have processed the results of chemical groundwater analysis in different aquifers of Tomsk district (Tomsk Oblast, Russia). More than 8400 samples of chemical groundwater analyses were taken during long-term observation period. Human health risk assessment of exposure to contaminants in drinking water was performed in accordance with the risk assessment guidance for public health concerning chemical pollution of the environment (Russian reference number: 2.1.10.1920-04-M, 2004). Identified potential risks were estimated for consuming water of each aquifer. The comparative analysis of water quality of different aquifers was performed on the basis of the risk coefficient of the total non-carcinogenic effects. The non-carcinogenic risk for the health of the Tomsk district population due to groundwater consumption without prior sanitary treatment was admitted acceptable. A rather similar picture is observed for all aquifers, although deeper aquifers show lower hazard coefficients.

  12. Susceptibility of Microsporum canis arthrospores to a mixture of chemically defined essential oils: a perspective for environmental decontamination.

    Science.gov (United States)

    Nardoni, Simona; Tortorano, Annamaria; Mugnaini, Linda; Profili, Greta; Pistelli, Luisa; Giovanelli, Silvia; Pisseri, Francesca; Papini, Roberto; Mancianti, Francesca

    2015-01-01

    The zoophilic dermatophyte Microsporum canis has cats as natural reservoir, but it is able to infect a wide range of hosts, including humans, where different clinical features of the so-called ringworm dermatophytosis have been described. Human infections are increasingly been reported in Mediterranean countries. A reliable control program against M. canis infection in cats should include an antifungal treatment of both the infected animals and their living environment. In this article, a herbal mixture composed of chemically defined essential oils (EOs) of Litsea cubeba (1%), Illicium verum, Foeniculum vulgare, and Pelargonium graveolens (0.5% each) was formulated and its antifungal activity assessed against M. canis arthrospores which represent the infective environmental stage of M. canis. Single compounds present in higher amounts in the mixture were also separately tested in vitro. Litsea cubeba and P. graveolens EOs were most effective (minimum inhibitory concentration (MIC) 0.5%), followed by EOs of I. verum (MIC 2%) and F. vulgare (MIC 2.5%). Minimum fungicidal concentrations (MFC) values were 0.75% (L. cubeba), 1.5% (P. graveolens), 2.5% (I. verum) and 3% (F. vulgare). MIC and MFC values of the mixture were 0.25% and 0.5%, respectively. The daily spray of the mixture (200 μL) directly onto infected hairs inhibited fungal growth from the fourth day onwards. The compounds present in higher amounts exhibited variable antimycotic activity, with MIC values ranging from >10% (limonene) to 0.1% (geranial and neral). Thus, the mixture showed a good antifungal activity against arthrospores present in infected hairs. These results are promising for a further application of the mixture as an alternative tool or as an adjuvant in the environmental control of feline microsporosis. PMID:25854840

  13. Resistance to chemical disinfection under conditions of microgravity

    Science.gov (United States)

    Marchin, George L.

    1998-01-01

    In unit gravity, bacteria and disinfecting resin beads co-sediment to the septum in a fluid processing apparatus (FPA) resulting in effective chemical disinfection. In microgravity bacteria in suspension have access to a larger volume of the FPA because of a lack of sedimentation. Further, when disinfecting resin beads are added to the FPA they also remain in suspension reducing their effective concentration. Typically, therefore, disinfection experiments in microgravity return larger numbers of viable bacteria than ground-based controls. Preliminary experiments aboard the MIR Space Station with Pseudomonas aeruginosa additionally suggest that the longer bacteria are retained in microgravity the more resistant they become to chemical disinfection. This phenomenon is probably due to additional time to develop resistant biofilms on the interior of the FPA. To partially solve these problems we have developed additional disinfecting materials to use in conjunction with polyiodide containing resin beads. One of these materials carbon beads coated with 3-trimethoxy silylpropyl dimethyloctadecyl ammonium chloride (Dow-Corning 5700®), acts synergistically with polyiodide resin disinfectants. Carbon beads so treated are still able to remove aqueous iodine from the water stream while providing an additional level of chemical disinfection. This additional capability prevents contamination of the carbon beads with heterotrophic bacteria and insures that bacteria surviving iodine disinfection are efficiently devitalized.

  14. Sign conditions for injectivity of generalized polynomial maps with applications to chemical reaction networks and real algebraic geometry

    DEFF Research Database (Denmark)

    Müller, Stefan; Feliu, Elisenda; Regensburger, Georg;

    2016-01-01

    We give necessary and sufficient conditions in terms of sign vectors for the injectivity of families of polynomials maps with arbitrary real exponents defined on the positive orthant. Our work relates and extends existing injectivity conditions expressed in terms of Jacobian matrices and determin...... determinants. In the context of chemical reaction networks with power-law kinetics, our results can be used to preclude as well as to guarantee multiple positive steady states. In the context of real algebraic geometry, our results reveal the first ...

  15. Derivation of transgene-free human induced pluripotent stem cells from human peripheral T cells in defined culture conditions.

    Directory of Open Access Journals (Sweden)

    Yoshikazu Kishino

    Full Text Available Recently, induced pluripotent stem cells (iPSCs were established as promising cell sources for revolutionary regenerative therapies. The initial culture system used for iPSC generation needed fetal calf serum in the culture medium and mouse embryonic fibroblast as a feeder layer, both of which could possibly transfer unknown exogenous antigens and pathogens into the iPSC population. Therefore, the development of culture systems designed to minimize such potential risks has become increasingly vital for future applications of iPSCs for clinical use. On another front, although donor cell types for generating iPSCs are wide-ranging, T cells have attracted attention as unique cell sources for iPSCs generation because T cell-derived iPSCs (TiPSCs have a unique monoclonal T cell receptor genomic rearrangement that enables their differentiation into antigen-specific T cells, which can be applied to novel immunotherapies. In the present study, we generated transgene-free human TiPSCs using a combination of activated human T cells and Sendai virus under defined culture conditions. These TiPSCs expressed pluripotent markers by quantitative PCR and immunostaining, had a normal karyotype, and were capable of differentiating into cells from all three germ layers. This method of TiPSCs generation is more suitable for the therapeutic application of iPSC technology because it lowers the risks associated with the presence of undefined, animal-derived feeder cells and serum. Therefore this work will lead to establishment of safer iPSCs and extended clinical application.

  16. Conscious worst case definition for risk assessment, part I: a knowledge mapping approach for defining most critical risk factors in integrative risk management of chemicals and nanomaterials.

    Science.gov (United States)

    Sørensen, Peter B; Thomsen, Marianne; Assmuth, Timo; Grieger, Khara D; Baun, Anders

    2010-08-15

    This paper helps bridge the gap between scientists and other stakeholders in the areas of human and environmental risk management of chemicals and engineered nanomaterials. This connection is needed due to the evolution of stakeholder awareness and scientific progress related to human and environmental health which involves complex methodological demands on risk management. At the same time, the available scientific knowledge is also becoming more scattered across multiple scientific disciplines. Hence, the understanding of potentially risky situations is increasingly multifaceted, which again challenges risk assessors in terms of giving the 'right' relative priority to the multitude of contributing risk factors. A critical issue is therefore to develop procedures that can identify and evaluate worst case risk conditions which may be input to risk level predictions. Therefore, this paper suggests a conceptual modelling procedure that is able to define appropriate worst case conditions in complex risk management. The result of the analysis is an assembly of system models, denoted the Worst Case Definition (WCD) model, to set up and evaluate the conditions of multi-dimensional risk identification and risk quantification. The model can help optimize risk assessment planning by initial screening level analyses and guiding quantitative assessment in relation to knowledge needs for better decision support concerning environmental and human health protection or risk reduction. The WCD model facilitates the evaluation of fundamental uncertainty using knowledge mapping principles and techniques in a way that can improve a complete uncertainty analysis. Ultimately, the WCD is applicable for describing risk contributing factors in relation to many different types of risk management problems since it transparently and effectively handles assumptions and definitions and allows the integration of different forms of knowledge, thereby supporting the inclusion of multifaceted risk

  17. Measurements for the production of aluminium oxide ceramics with defined microstructure parameters by using colloidal-chemical processings

    International Nuclear Information System (INIS)

    The aim of this work is to verify the influences of the different single procedure steps on the microstructure of sintered alumina and to get a correlation between the product characteristics and the characteristic data. The powder production was carried out by using the sol-gel-process followed by freeze-drying of the gel. From the boehmit-powder porous and inhomogen microstructure of the sintered pellets was obtained. The unfavourable morphology of the hydroxide-powder could be eliminated by pre-calcination followed by powder-milling. Because of the wet-milling after the pre-calcination the powder was doped with α-Al2O3, caused by the abrasion of the milling-mug and -balls, and therefore the calcinating temperature could be reduced to 1050deg C. Two charges of the colloidal-chemical produced powder and four commercial powders with different characteristics with regard to the purity or doping and particle-size and -distribution were compared with themselves. These powders were cold-isostatically pressed and sintered under different conditions. It could be shown that the influence of the impurities on the microstructure is higher than the influence of the grain size distribution. Impurities lead to a discontinous grain size distribution and intracristalline pores in sintered bodies, even using powders with a small grain size distribution. Measurements on the slip casted samples yielded for all powders different relationships between the viscosity and the pH. There was no visible influence of different pH-values on the microstructure (pH always measured at the minimum of the viscosity). Here the influence of the purity and the grain size distribution on the microstructure was less pronounced compared with the isostatically pressed ceramics. (orig.)

  18. BLACK HOLE FORMATION IN PRIMORDIAL GALAXIES: CHEMICAL AND RADIATIVE CONDITIONS

    International Nuclear Information System (INIS)

    In massive primordial galaxies, the gas may directly collapse and form a single central massive object if cooling is suppressed. H2 line cooling can be suppressed in the presence of a strong soft-ultraviolet radiation field, but the role played by other cooling mechanisms is less clear. In optically thin gas, Lyα cooling can be very effective, maintaining the gas temperature below 104 K over many orders of magnitude in density. However, the large neutral hydrogen column densities present in primordial galaxies render them highly optically thick to Lyα photons. In this paper, we examine in detail the effects of the trapping of these Lyα photons on the thermal and chemical evolution of the gas. We show that despite the high optical depth in the Lyman series lines, cooling is not strongly suppressed, and proceeds via other atomic hydrogen transitions. At densities larger than ∼109 cm-3, collisional dissociation of molecular hydrogen becomes the dominant cooling process and decreases the gas temperature to about 5000 K. The gas temperature evolves with density as T∝ργeff-1, with γeff = 0.97-0.98. The evolution is thus very close to isothermal, and so fragmentation is possible, but unlikely to occur during the initial collapse. However, after the formation of a massive central object, we expect that later-infalling, higher angular momentum material will form an accretion disk that may be unstable to fragmentation, which may give rise to star formation with a top-heavy initial mass function.

  19. Optimizing cyanobacteria growth conditions in a sealed environment to enable chemical inhibition tests with volatile chemicals.

    Science.gov (United States)

    Johnson, Tylor J; Zahler, Jacob D; Baldwin, Emily L; Zhou, Ruanbao; Gibbons, William R

    2016-07-01

    Cyanobacteria are currently being engineered to photosynthetically produce next-generation biofuels and high-value chemicals. Many of these chemicals are highly toxic to cyanobacteria, thus strains with increased tolerance need to be developed. The volatility of these chemicals may necessitate that experiments be conducted in a sealed environment to maintain chemical concentrations. Therefore, carbon sources such as NaHCO3 must be used for supporting cyanobacterial growth instead of CO2 sparging. The primary goal of this study was to determine the optimal initial concentration of NaHCO3 for use in growth trials, as well as if daily supplementation of NaHCO3 would allow for increased growth. The secondary goal was to determine the most accurate method to assess growth of Anabaena sp. PCC 7120 in a sealed environment with low biomass titers and small sample volumes. An initial concentration of 0.5g/L NaHCO3 was found to be optimal for cyanobacteria growth, and fed-batch additions of NaHCO3 marginally improved growth. A separate study determined that a sealed test tube environment is necessary to maintain stable titers of volatile chemicals in solution. This study also showed that a SYTO® 9 fluorescence-based assay for cell viability was superior for monitoring filamentous cyanobacterial growth compared to absorbance, chlorophyll α (chl a) content, and biomass content due to its accuracy, small sampling size (100μL), and high throughput capabilities. Therefore, in future chemical inhibition trials, it is recommended that 0.5g/L NaHCO3 is used as the carbon source, and that culture viability is monitored via the SYTO® 9 fluorescence-based assay that requires minimum sample size. PMID:27196637

  20. Chemical durability of hollandite ceramic for conditioning cesium

    Energy Technology Data Exchange (ETDEWEB)

    Angeli, Frederic [CEA Marcoule, DEN/DTCD/SECM/LCLT, F-30207 Bagnols-sur-Ceze (France)], E-mail: frederic.angeli@cea.fr; McGlinn, Peter [ANSTO, New Illawarra Road, Menai, PMB1, NSW 2234 (Australia); Frugier, Pierre [CEA Marcoule, DEN/DTCD/SECM/LCLT, F-30207 Bagnols-sur-Ceze (France)

    2008-10-15

    The aqueous corrosion behavior of Cs-doped hollandite ceramic (BaCs{sub 0.28}Fe{sub 0.82}Al{sub 1.46}Ti{sub 5.72}O{sub 16}) was studied using several different static experimental protocols, with leachants of varying pH, and at different surface area to volume ratios, for periods ranging from six months to three years. All leach tests were carried out at 90 deg. C. X-ray diffraction (XRD) and scanning electron microscopy (SEM), coupled with energy dispersive X-ray spectroscopy (EDS), were used to characterize the surfaces of the hollandite before and after leaching. The most pronounced elemental releases, and corresponding changes to surface composition and microstructure, was evident at low pH, in particular pH 1. Cs and Ba releases were highest at low pH, with surface alteration exhibited by the formation of secondary rutile (prevalent at pH 1) and Al- and Ba-depleted hollandite (prevalent at pH 2). After rapid initial Cs release, the alteration rate was extremely low over the pH range from 2 to 10, as well as in pure water experiments with a sample-surface-area-to-solution-volume ratio ranging from 0.1 cm{sup -1} to 1200 cm{sup -1}. The rates were about 10{sup -5} g m{sup -2} d{sup -1}, corresponding to alteration thicknesses of a few nanometers per year. Higher rates (5 x 10{sup -3} g m{sup -2} d{sup -1}) were observed only under very acidic conditions (pH 1). Congruency in Cs and Ba releases occurred only at pH 1, with incongruency between the two elements increasing with increasing pH. There were no apparent solubility constraints on Cs releases regardless of the SA/V ratio, whereas geochemical modeling suggested that Ba releases could have been affected by the formation of BaCO{sub 3}, particularly at high SA/V ratios. Extended leaching (with the leachant renewed once after 261 days of leaching) confirmed the high durability of hollandite with altered thicknesses of less than one nanometer per year over the last two years. Whilst Cs depletion of the

  1. Focal Uncaging of GABA Reveals a Temporally Defined Role for GABAergic Inhibition during Appetitive Associative Olfactory Conditioning in Honeybees

    Science.gov (United States)

    Raccuglia, Davide; Mueller, Uli

    2013-01-01

    Throughout the animal kingdom, the inhibitory neurotransmitter ?-aminobutyric acid (GABA) is a key modulator of physiological processes including learning. With respect to associative learning, the exact time in which GABA interferes with the molecular events of learning has not yet been clearly defined. To address this issue, we used two…

  2. In vitro fertilization (IVF) from low or high antral follicle count pubertal beef heifers using semi-defined culture conditions

    Science.gov (United States)

    Antral follicle counts (AFC) vary among pubertal beef heifers. Our objective was to compare the in vitro maturation and fertilization of oocytes collected from low and high AFC heifers. Previously we reported results using serum-based IVF media and in this study report results using semi-defined m...

  3. Development of a chemically defined medium and discovery of new mitogenic growth factors for mouse hepatocytes: mitogenic effects of FGF1/2 and PDGF.

    Directory of Open Access Journals (Sweden)

    William C Bowen

    Full Text Available Chemically defined serum-free media for rat hepatocytes have been useful in identifying EGFR ligands and HGF/MET signaling as direct mitogenic factors for rat hepatocytes. The absence of such media for mouse hepatocytes has prevented screening for discovery of such mitogens for mouse hepatocytes. We present results obtained by designing such a chemically defined medium for mouse hepatocytes and demonstrate that in addition to EGFR ligands and HGF, the growth factors FGF1 and FGF2 are also important mitogenic factors for mouse hepatocytes. Smaller mitogenic response was also noticed for PDGF AB. Mouse hepatocytes are more likely to enter into spontaneous proliferation in primary culture due to activation of cell cycle pathways resulting from collagenase perfusion. These results demonstrate unanticipated fundamental differences in growth biology of hepatocytes between the two rodent species.

  4. A Small Molecule that Promotes Cardiac Differentiation of Human Pluripotent Stem Cells under Defined, Cytokine- and Xeno-free Conditions

    Directory of Open Access Journals (Sweden)

    Itsunari Minami

    2012-11-01

    Full Text Available Human pluripotent stem cells (hPSCs, including embryonic stem cells and induced pluripotent stem cells, are potentially useful in regenerative therapies for heart disease. For medical applications, clinical-grade cardiac cells must be produced from hPSCs in a defined, cost-effective manner. Cell-based screening led to the discovery of KY02111, a small molecule that promotes differentiation of hPSCs to cardiomyocytes. Although the direct target of KY02111 remains unknown, results of the present study suggest that KY02111 promotes differentiation by inhibiting WNT signaling in hPSCs but in a manner that is distinct from that of previously studied WNT inhibitors. Combined use of KY02111 and WNT signaling modulators produced robust cardiac differentiation of hPSCs in a xeno-free, defined medium, devoid of serum and any kind of recombinant cytokines and hormones, such as BMP4, Activin A, or insulin. The methodology has potential as a means for the practical production of human cardiomyocytes for regeneration therapies.

  5. Routine experimental system for defining conditions used in photodynamic therapy and fluorescence photodetection of (non-) neoplastic epithelia

    Science.gov (United States)

    Lange, Norbert; Vaucher, Laurent; Marti, Alexandre; Etter, Anne-Lise; Gerber, Patrick; van den Bergh, Hubert; Jichlinski, Patrice; Kucera, Pavel

    2001-04-01

    A common method to induce enhanced short-term endogenous porphyrin synthesis and accumulation in cell is the topical, systemic application of 5-aminolevulinic acid or one of its derivatives. This circumvents the intravenous administration of photosensitizers normally used for photodynamic therapy (PDT) of fluorescence photodetection. However, in the majority of potential medical indications, optimal conditions with respect to the porphyrin precursor or its pharmaceutical formulation have not yet been found. Due to ethical restrictions and animal right directives, the number of available test objects is limited. Hence, definition and use of nonanimal test methods are needed. Tissue and organ cultures are a promising approach in replacing cost intensive animal models in early stages of drug development. In this paper, we present a tissue culture, which can among others be used routinely to answer specific questions emerging in the field of photodynamic therapy and fluorescence photodetection. This technique uses mucosae excised from sheep paranasal sinuses or pig bladder, which is cultured under controlled conditions. It allows quasiquantative testing of different protoporphyrin IX precursors with respect to dose-response curves and pharmacokinetics, as well as the evaluation of different incubation conditions and/or different drug formulations. Furthermore, this approach, when combined with the use of electron microscopy and fluorescence-based methods, can be used to quantitatively determine the therapeutic outcome following protoporphyrin IX-mediated PDT.

  6. The use of biodiversity as source of new chemical entities against defined molecular targets for treatment of malaria, tuberculosis, and T-cell mediated diseases: a review

    Directory of Open Access Journals (Sweden)

    Luiz Augusto Basso

    2005-10-01

    Full Text Available The modern approach to the development of new chemical entities against complex diseases, especially the neglected endemic diseases such as tuberculosis and malaria, is based on the use of defined molecular targets. Among the advantages, this approach allows (i the search and identification of lead compounds with defined molecular mechanisms against a defined target (e.g. enzymes from defined pathways, (ii the analysis of a great number of compounds with a favorable cost/benefit ratio, (iii the development even in the initial stages of compounds with selective toxicity (the fundamental principle of chemotherapy, (iv the evaluation of plant extracts as well as of pure substances. The current use of such technology, unfortunately, is concentrated in developed countries, especially in the big pharma. This fact contributes in a significant way to hamper the development of innovative new compounds to treat neglected diseases. The large biodiversity within the territory of Brazil puts the country in a strategic position to develop the rational and sustained exploration of new metabolites of therapeutic value. The extension of the country covers a wide range of climates, soil types, and altitudes, providing a unique set of selective pressures for the adaptation of plant life in these scenarios. Chemical diversity is also driven by these forces, in an attempt to best fit the plant communities to the particular abiotic stresses, fauna, and microbes that co-exist with them. Certain areas of vegetation (Amazonian Forest, Atlantic Forest, Araucaria Forest, Cerrado-Brazilian Savanna, and Caatinga are rich in species and types of environments to be used to search for natural compounds active against tuberculosis, malaria, and chronic-degenerative diseases. The present review describes some strategies to search for natural compounds, whose choice can be based on ethnobotanical and chemotaxonomical studies, and screen for their ability to bind to immobilized

  7. Defined Conditions for the Isolation and Expansion of Basal Prostate Progenitor Cells of Mouse and Human Origin

    OpenAIRE

    Thomas Höfner; Christian Eisen; Corinna Klein; Teresa Rigo-Watermeier; Stephan M. Goeppinger; Anna Jauch; Brigitte Schoell; Vanessa Vogel; Elisa Noll; Wilko Weichert; Irène Baccelli; Anja Schillert; Steve Wagner; Sascha Pahernik; Martin R. Sprick

    2015-01-01

    Summary Methods to isolate and culture primary prostate epithelial stem/progenitor cells (PESCs) have proven difficult and ineffective. Here, we present a method to grow and expand both murine and human basal PESCs long term in serum- and feeder-free conditions. The method enriches for adherent mouse basal PESCs with a Lin−SCA-1+CD49f+TROP2high phenotype. Progesterone and sodium selenite are additionally required for the growth of human Lin−CD49f+TROP2high PESCs. The gene-expression profiles ...

  8. About evolution of alive orgamisms in conditions of radioactive and chemical stress (biophysical aspect)

    International Nuclear Information System (INIS)

    The problems of evolution of living organisms in conditions of radioactive and chemical stress are considered. Tendencies of development of the world community are evidence of global anthropogenic influence increase on biosphere, which is caused by many components, the main of them being radiation contamination and chemical pollution. The possible mechanisms of new species appearance are discussed on molecular level taking into account mutagenic factors caused by radiation and chemical stress. The quantum field hypothesis on the basis of Landau-Ginzburg equation of molecular mechanisms of mutations connected with new species appearance is presented.(A.A.D.)

  9. Defined conditions for the isolation and expansion of basal prostate progenitor cells of mouse and human origin.

    Science.gov (United States)

    Höfner, Thomas; Eisen, Christian; Klein, Corinna; Rigo-Watermeier, Teresa; Goeppinger, Stephan M; Jauch, Anna; Schoell, Brigitte; Vogel, Vanessa; Noll, Elisa; Weichert, Wilko; Baccelli, Irène; Schillert, Anja; Wagner, Steve; Pahernik, Sascha; Sprick, Martin R; Trumpp, Andreas

    2015-03-10

    Methods to isolate and culture primary prostate epithelial stem/progenitor cells (PESCs) have proven difficult and ineffective. Here, we present a method to grow and expand both murine and human basal PESCs long term in serum- and feeder-free conditions. The method enriches for adherent mouse basal PESCs with a Lin(-)SCA-1(+)CD49f(+)TROP2(high) phenotype. Progesterone and sodium selenite are additionally required for the growth of human Lin(-)CD49f(+)TROP2(high) PESCs. The gene-expression profiles of expanded basal PESCs show similarities to ESCs, and NF-kB function is critical for epithelial differentiation of sphere-cultured PESCs. When transplanted in combination with urogenital sinus mesenchyme, expanded mouse and human PESCs generate ectopic prostatic tubules, demonstrating their stem cell activity in vivo. This novel method will facilitate the molecular, genomic, and functional characterization of normal and pathologic prostate glands of mouse and human origin. PMID:25702639

  10. Comprehensive clinical studies in 34 patients with molecularly defined UPD(14)pat and related conditions (Kagami-Ogata syndrome).

    Science.gov (United States)

    Kagami, Masayo; Kurosawa, Kenji; Miyazaki, Osamu; Ishino, Fumitoshi; Matsuoka, Kentaro; Ogata, Tsutomu

    2015-11-01

    Paternal uniparental disomy 14 (UPD(14)pat) and epimutations and microdeletions affecting the maternally derived 14q32.2 imprinted region lead to a unique constellation of clinical features such as facial abnormalities, small bell-shaped thorax with a coat-hanger appearance of the ribs, abdominal wall defects, placentomegaly, and polyhydramnios. In this study, we performed comprehensive clinical studies in patients with UPD(14)pat (n=23), epimutations (n=5), and microdeletions (n=6), and revealed several notable findings. First, a unique facial appearance with full cheeks and a protruding philtrum and distinctive chest roentgenograms with increased coat-hanger angles to the ribs constituted the pathognomonic features from infancy through childhood. Second, birth size was well preserved, with a median birth length of ±0 SD (range, -1.7 to +3.0 SD) and a median birth weight of +2.3 SD (range, +0.1 to +8.8 SD). Third, developmental delay and/or intellectual disability was invariably present, with a median developmental/intellectual quotient of 55 (range, 29-70). Fourth, hepatoblastoma was identified in three infantile patients (8.8%), and histological examination in two patients showed a poorly differentiated embryonal hepatoblastoma with focal macrotrabecular lesions and well-differentiated hepatoblastoma, respectively. These findings suggest the necessity of an adequate support for developmental delay and periodical screening for hepatoblastoma in the affected patients, and some phenotypic overlap between UPD(14)pat and related conditions and Beckwith-Wiedemann syndrome. On the basis of our previous and present studies that have made a significant contribution to the clarification of underlying (epi)genetic factors and the definition of clinical findings, we propose the name 'Kagami-Ogata syndrome' for UPD(14)pat and related conditions. PMID:25689926

  11. Defined Conditions for the Isolation and Expansion of Basal Prostate Progenitor Cells of Mouse and Human Origin

    Directory of Open Access Journals (Sweden)

    Thomas Höfner

    2015-03-01

    Full Text Available Methods to isolate and culture primary prostate epithelial stem/progenitor cells (PESCs have proven difficult and ineffective. Here, we present a method to grow and expand both murine and human basal PESCs long term in serum- and feeder-free conditions. The method enriches for adherent mouse basal PESCs with a Lin−SCA-1+CD49f+TROP2high phenotype. Progesterone and sodium selenite are additionally required for the growth of human Lin−CD49f+TROP2high PESCs. The gene-expression profiles of expanded basal PESCs show similarities to ESCs, and NF-kB function is critical for epithelial differentiation of sphere-cultured PESCs. When transplanted in combination with urogenital sinus mesenchyme, expanded mouse and human PESCs generate ectopic prostatic tubules, demonstrating their stem cell activity in vivo. This novel method will facilitate the molecular, genomic, and functional characterization of normal and pathologic prostate glands of mouse and human origin.

  12. Defined Conditions for the Isolation and Expansion of Basal Prostate Progenitor Cells of Mouse and Human Origin

    Science.gov (United States)

    Höfner, Thomas; Eisen, Christian; Klein, Corinna; Rigo-Watermeier, Teresa; Goeppinger, Stephan M.; Jauch, Anna; Schoell, Brigitte; Vogel, Vanessa; Noll, Elisa; Weichert, Wilko; Baccelli, Irène; Schillert, Anja; Wagner, Steve; Pahernik, Sascha; Sprick, Martin R.; Trumpp, Andreas

    2015-01-01

    Summary Methods to isolate and culture primary prostate epithelial stem/progenitor cells (PESCs) have proven difficult and ineffective. Here, we present a method to grow and expand both murine and human basal PESCs long term in serum- and feeder-free conditions. The method enriches for adherent mouse basal PESCs with a Lin−SCA-1+CD49f+TROP2high phenotype. Progesterone and sodium selenite are additionally required for the growth of human Lin−CD49f+TROP2high PESCs. The gene-expression profiles of expanded basal PESCs show similarities to ESCs, and NF-kB function is critical for epithelial differentiation of sphere-cultured PESCs. When transplanted in combination with urogenital sinus mesenchyme, expanded mouse and human PESCs generate ectopic prostatic tubules, demonstrating their stem cell activity in vivo. This novel method will facilitate the molecular, genomic, and functional characterization of normal and pathologic prostate glands of mouse and human origin. PMID:25702639

  13. Patient education, nudge, and manipulation: defining the ethical conditions of the person-centered model of care.

    Science.gov (United States)

    Reach, Gérard

    2016-01-01

    Patient education (PE) is expected to help patients with a chronic disease to manage their lives and give them the possibility of adopting, in an appropriate manner, beneficial changes in health behaviors that are prescribed by their physicians. It is aimed at delineating, agreeing on, and implementing a patient's personal action plan and is therefore an essential constituent of the person-centered model of care. The aim of this article is to examine the idea that PE may sometimes be a manipulation that is organized for the good of patients in a paternalistic framework. Theoretically, PE differs from manipulation by addressing the reflective intelligence of patients in full light and helping them make autonomous choices. In this article, we examined some analogies between PE and nudge (ie, techniques used to push people to make good choices by organizing their environment). This analysis suggests that PE is not always as transparent and reflective as it is supposed to be and that unmasking these issues may be useful for improving the ethical quality of educational practice that must be performed in a framework of a trusting patient-doctor relationship. Under this condition, PE may sometimes represent a form of persuasion without being accused of patient deception and manipulation: trust is therefore the core of the person-centered model of care. PMID:27103791

  14. Patient education, nudge, and manipulation: defining the ethical conditions of the person-centered model of care

    Science.gov (United States)

    Reach, Gérard

    2016-01-01

    Patient education (PE) is expected to help patients with a chronic disease to manage their lives and give them the possibility of adopting, in an appropriate manner, beneficial changes in health behaviors that are prescribed by their physicians. It is aimed at delineating, agreeing on, and implementing a patient’s personal action plan and is therefore an essential constituent of the person-centered model of care. The aim of this article is to examine the idea that PE may sometimes be a manipulation that is organized for the good of patients in a paternalistic framework. Theoretically, PE differs from manipulation by addressing the reflective intelligence of patients in full light and helping them make autonomous choices. In this article, we examined some analogies between PE and nudge (ie, techniques used to push people to make good choices by organizing their environment). This analysis suggests that PE is not always as transparent and reflective as it is supposed to be and that unmasking these issues may be useful for improving the ethical quality of educational practice that must be performed in a framework of a trusting patient–doctor relationship. Under this condition, PE may sometimes represent a form of persuasion without being accused of patient deception and manipulation: trust is therefore the core of the person-centered model of care. PMID:27103791

  15. Patient education, nudge, and manipulation: defining the ethical conditions of the person-centered model of care

    Directory of Open Access Journals (Sweden)

    Reach G

    2016-04-01

    Full Text Available Gérard Reach1,2 1Department of Endocrinology, Diabetes and Metabolic Diseases, Avicenne Hospital AP-HP, 2EA 3412, Centre de Recherche en Nutrition Humaine Ile-de-France (CRNH-IDF, Paris 13 University, Sorbonne Paris Cité, Bobigny, France Abstract: Patient education (PE is expected to help patients with a chronic disease to manage their lives and give them the possibility of adopting, in an appropriate manner, beneficial changes in health behaviors that are prescribed by their physicians. It is aimed at delineating, agreeing on, and implementing a patient’s personal action plan and is therefore an essential constituent of the person-centered model of care. The aim of this article is to examine the idea that PE may sometimes be a manipulation that is organized for the good of patients in a paternalistic framework. Theoretically, PE differs from manipulation by addressing the reflective intelligence of patients in full light and helping them make autonomous choices. In this article, we examined some analogies between PE and nudge (ie, techniques used to push people to make good choices by organizing their environment. This analysis suggests that PE is not always as transparent and reflective as it is supposed to be and that unmasking these issues may be useful for improving the ethical quality of educational practice that must be performed in a framework of a trusting patient–doctor relationship. Under this condition, PE may sometimes represent a form of persuasion without being accused of patient deception and manipulation: trust is therefore the core of the person-centered model of care. Keywords: patient education, adherence, autonomy, nudge, persuasion, manipulation, deception, trust, person-centered care model, shared decision-making

  16. Protecting capacity against malaria of chemically defined tetramer forms based on the Plasmodium falciparum apical sushi protein as potential vaccine components.

    Science.gov (United States)

    Vanegas, Magnolia; Bermúdez, Adriana; Guerrero, Yuly Andrea; Cortes-Vecino, Jesús Alfredo; Curtidor, Hernando; Patarroyo, Manuel Elkin; Lozano, José Manuel

    2014-08-15

    Developing novel generations of subunit-based antimalarial vaccines in the form of chemically-defined macromolecule systems for multiple antigen presentation represents a classical problem in the field of vaccine development. Many efforts involving synthesis strategies leading to macromolecule constructs have been based on dendrimer-like systems, the condensation of large building blocks and conventional asymmetric double dimer constructs, all based on lysine cores. This work describes novel symmetric double dimer and condensed linear constructs for presenting selected peptide multi-copies from the apical sushi protein expressed in Plasmodium falciparum. These molecules have been proved to be safe and innocuous, highly antigenic and have shown strong protective efficacy in rodents challenged with two Plasmodium species. Insights into systematic design, synthesis and characterisation have led to such novel antigen systems being used as potential platforms for developing new anti-malarial vaccine candidates. PMID:25063026

  17. Chemically defined diet alters the protective properties of fructo-oligosaccharides and isomalto-oligosaccharides in HLA-B27 transgenic rats.

    Directory of Open Access Journals (Sweden)

    Petya Koleva

    Full Text Available Non-digestible oligosaccharides (NDO were shown to reduce inflammation in experimental colitis, but it remains unclear whether microbiota changes mediate their colitis-modulating effects. This study assessed intestinal microbiota and intestinal inflammation after feeding chemically defined AIN-76A or rat chow diets, with or without supplementation with 8 g/kg body weight of fructo-oligosaccharides (FOS or isomalto-oligosaccharides (IMO. The study used HLA-B27 transgenic rats, a validated model of inflammatory bowel disease (IBD, in a factorial design with 6 treatment groups. Intestinal inflammation and intestinal microbiota were analysed after 12 weeks of treatment. FOS and IMO reduced colitis in animals fed rat chow, but exhibited no anti-inflammatory effect when added to AIN-76A diets. Both NDO induced specific but divergent microbiota changes. Bifidobacteria and Enterobacteriaceae were stimulated by FOS, whereas copy numbers of Clostridium cluster IV were decreased. In addition, higher concentrations of total short-chain fatty acids (SCFA were observed in cecal contents of rats on rat chow compared to the chemically defined diet. AIN-76A increased the relative proportions of propionate, iso-butyrate, valerate and iso-valerate irrespective of the oligosaccharide treatment. The SCFA composition, particularly the relative concentration of iso-butyrate, valerate and iso-valerate, was associated (P ≤ 0.004 and r ≥ 0.4 with increased colitis and IL-1 β concentration of the cecal mucosa. This study demonstrated that the protective effects of fibres on colitis development depend on the diet. Although diets modified specific cecal microbiota, our study indicates that these changes were not associated with colitis reduction. Intestinal inflammation was positively correlated to protein fermentation and negatively correlated with carbohydrate fermentation in the large intestine.

  18. Chemically transferable coarse-grained potentials from conditional reversible work calculations.

    Science.gov (United States)

    Brini, E; van der Vegt, N F A

    2012-10-21

    The representability and transferability of effective pair potentials used in multiscale simulations of soft matter systems is ill understood. In this paper, we study liquid state systems composed of n-alkanes, the coarse-grained (CG) potential of which may be assumed pairwise additive and has been obtained using the conditional reversible work (CRW) method. The CRW method is a free-energy-based coarse-graining procedure, which, by means of performing the coarse graining at pair level, rigorously provides a pair potential that describes the interaction free energy between two mapped atom groups (beads) embedded in their respective chemical environments. The pairwise nature of the interactions combined with their dependence on the chemically bonded environment makes CRW potentials ideally suited in studies of chemical transferability. We report CRW potentials for hexane using a mapping scheme that merges two heavy atoms in one CG bead. It is shown that the model is chemically and thermodynamically transferable to alkanes of different chain lengths in the liquid phase at temperatures between the melting and the boiling point under atmospheric (1 atm) pressure conditions. It is further shown that CRW-CG potentials may be readily obtained from a single simulation of the liquid state using the free energy perturbation method, thereby providing a fast and versatile molecular coarse graining method for aliphatic molecules. PMID:23083154

  19. Conscious worst case definition for risk assessment, part I. A knowledge mapping approach for defining most critical risk factors in integrative risk management of chemicals and nanomaterials

    DEFF Research Database (Denmark)

    Sørensen, P.S.; Thomsen, M.; Assmuth, T.;

    2010-01-01

    a conceptual modelling procedure that is able to define appropriate worst case conditions in complex risk management. The result of the analysis is an assembly of system models, denoted the Worst Case Definition (WCD) model, to set up and evaluate the conditions of multi-dimensional risk...... environmental health which involves complex methodological demands on risk management. At the same time, the available scientific knowledge is also becoming more scattered across multiple scientific disciplines. Hence, the understanding of potentially risky situations is increasingly multifaceted, which again...... transparently and effectively handles assumptions and definitions and allows the integration of different forms of knowledge, thereby supporting the inclusion of multifaceted risk components in cumulative risk management....

  20. Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

    OpenAIRE

    M. Isabel Burguete; Eduardo García-Verdugo; Luis, Santiago V.

    2011-01-01

    This paper reviews the current trends in the combined use of supported catalytic systems, either on solid supports or in liquid phases and supercritical fluids (scFs), to develop selective and enantioselective chemical transformations under continuous and semi-continuous flow conditions. The results presented have been selected to highlight how the combined use of those two elements can contribute to: (i) Significant improvements in productivity as a result of the enhanced diffusion of substr...

  1. Influence of Chemical Conditions on the Nanoporous Structure of Silicate Aerogels

    Directory of Open Access Journals (Sweden)

    Katalin Sinkó

    2010-01-01

    Full Text Available Silica or various silicate aerogels can be characterized by highly porous, open cell, low density structures. The synthesis parameters influence the three-dimensional porous structures by modifying the kinetics and mechanism of hydrolysis and condensation processes. Numerous investigations have shown that the structure of porous materials can be tailored by variations in synthesis conditions (e.g., the type of precursors, catalyst, and surfactants; the ratio of water/precursor; the concentrations; the medium pH; and the solvent. The objectives of this review are to summarize and elucidate the effects of chemical conditions on the nanoporous structure of sol-gel derived silicate aerogels.

  2. Decomposition Dynamics and Changes in Chemical Composition of Wheat Straw Residue under Anaerobic and Aerobic Conditions

    Science.gov (United States)

    Gao, Hongjian; Chen, Xi; Wei, Junling; Zhang, Yajie; Zhang, Ligan; Chang, Jiang; Thompson, Michael L.

    2016-01-01

    Soil aeration is a crucial factor that regulates crop residue decomposition, and the chemical composition of decomposing crop residues may change the forms and availability of soil nutrients, such as N and P. However, to date, differences in the chemical composition of crop straw residues after incorporation into soil and during its decomposition under anaerobic vs. aerobic conditions have not been well documented. The objective of the present study was to assess changes in the C-containing functional groups of wheat straw residue during its decomposition in anaerobic and aerobic environments. A 12-month incubation experiment was carried out to investigate the temporal variations of mass, carbon, and nitrogen loss, as well as changes in the chemical composition of wheat (Triticum aestivum L) straw residues under anaerobic and aerobic conditions by measuring C-containing functional groups using solid state nuclear magnetic resonance (NMR) spectroscopy. The residual mass, carbon content, and nitrogen content of the straw residue sharply declined during the initial 3 months, and then slowly decreased during the last incubation period from 3 to 12 months. The decomposition rate constant (k) for mass loss under aerobic conditions (0.022 d-1) was higher than that under anaerobic conditions (0.014 d-1). The residual mass percentage of cellulose and hemicellulose in the wheat straw gradually declined, whereas that of lignin gradually increased during the entire 12-month incubation period. The NMR spectra of C-containing functional groups in the decomposing straw under both aerobic and anaerobic conditions were similar at the beginning of the incubation as well as at 1 month, 6 months, and 12 months. The main alterations in C-containing functional groups during the decomposition of wheat straw were a decrease in the relative abundances of O-alkyl C and an increase in the relative abundances of alkyl C, aromatic C and COO/N-C = O functional groups. The NMR signals of alkyl C

  3. Pluripotent and Metabolic Features of Two Types of Porcine iPSCs Derived from Defined Mouse and Human ES Cell Culture Conditions.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available The domestic pig is an excellent animal model for stem cell research and clinical medicine. There is still no suitable culture condition to generate authentic porcine embryonic stem cells (pESCs and high quality porcine induced pluripotent stem cells (piPSCs. In this study, we found that culture conditions affected pluripotent and metabolic features of piPSCs. Using defined human embryonic stem cell (hESC and mouse ESC (mESC culture conditions, we generated two types of piPSCs, one of which was morphologically similar to hESCs (here called hpiPSCs, the other resembled mESCs (here called mpiPSCs. Transcriptome analysis and signaling pathway inhibition results suggested that mpiPSCs shared more of mESC signaling pathways, such as the BMP pathway and JAK/STAT pathway and hpiPSCs shared more hESC signaling pathways, such as the FGF pathway. Importantly, the mpiPSCs performed embryonic chimera incorporation more efficiently than the hpiPSCs did. In addition, the mpiPSCs showed mitochondrial features of naive ESCs and lipid droplets accumulation. These evidences may facilitate understanding of the gene regulation network and metabolism in piPSCs and promote derivation of bona fide pESCs for translational medicine.

  4. Use of water activity characteristics enables a simplified approach for defining the reference moisture condition for FDA cocoa powder in-house reference material.

    Science.gov (United States)

    Cunningham, W C

    2013-10-01

    The Food and Drug Administration uses water activity behavior characteristics when adjusting test portion mass to correct for the moisture condition of its cocoa powder in-house reference material. The cocoa powder's moisture condition, and therefore weight, equilibrates according to the relative humidity (RH) of its surroundings. This process is predictable and defined by an isotherm. The reference values in the certificate of analysis are relative to the material's condition at 30% RH, which is assumed to be mid-range for typical laboratory settings. Since mass variations are relatively small within a 15-50% RH range, the mass may be measured immediately after removing a test portion from a storage bottle and used without correction if a standard uncertainty of 0.7% is acceptable for the mass. If greater accuracy is needed and the laboratory RH is known, a very simple and quick procedure can be used whereby the test portion is left open and exposed to the laboratory air overnight before weighing. After applying a correction, the standard uncertainty for mass measurement drops to 0.3%. PMID:23942587

  5. Effect of UHT processing and storage conditions on physico-chemical characteristics of buffalo skim milk

    International Nuclear Information System (INIS)

    The obtained results indicated that physico-chemical and nutritional changes in UHT processed buffalo skimmed milk were more pronounced at 45 deg. C than 25 deg. C and 10 deg. C. Duration of storage adversely affected the chemical and nutritional quality of processed milk. A slight decrease in pH, total ash and lactose contents, was observed, whereas acidity was increased on the mentioned storage conditions. Total nitrogen and casein nitrogen contents gradually decreased during storage, whereas non-casein nitrogen (NCN) and non-protein nitrogen (NPN) increased to a great extent in samples stored at higher temperatures. A significant increase in hydroxyl methyl furfural (HMF) values occurred in UHT processed buffalo skim milk at 25 deg. C and 45 deg. C after of 90 days storage. Storage at high temperature (45 deg. C) caused undesirable effects on sensory properties, general quality characteristics and acceptability of UHT buffalo skimmed milk. (author)

  6. Chemical conditions in the repository for low- and intermediate-level reactor waste

    International Nuclear Information System (INIS)

    The chemical conditions in the proposed repositories for low- and intermediate-level reactor waste at Haestholmen (IVO) and Olkiluoto (TVO) have been discussed with respect to materials introduced into the repository, their possible long-term changes and interaction with groundwater flowing into the repository. The main possible groundwater-rock interactions have been discussed, as well as the role of micro-organisms, organic acids and colloids in the estimation of the barrier integrity. Experimental and theoretical studies have been performed on the basis of the natural groundwater compositions expected at the repository sites. Main emphasis is put on the chemical parameters which might influence the integrity of the different barriers in the repository as well as on the parameters which might effect the release and transport of radionuclides from the repository

  7. THE ESTIMATION OF DEPENDENCY OF FRESH BERRIES PHYSICO-CHEMICAL PROPERTIES ON STORAGE AND PROCESSING CONDITIONS

    Directory of Open Access Journals (Sweden)

    E. Sandulachi

    2010-01-01

    Full Text Available strawberries and raspberries in different level of ripeness. Here are presented: physico-chemical composition of the investigated samples, dry matter content, pH, anthocyanin content, polyphenols, ascorbic acid and K coefficient, which evidence oxido-reducing state of berries. It has been studied, also, the oxido-reducing state of this berries during storage condition.It was found that berries are rich in bioantioxidants. From physico-chemical point of view these fruits are in a reduced state, characterized by high values of index K. Biological value expressed by the oxidation-reducing state of berries depends on the ripeness level. Samples spectral analysis showed that depreciation of strawberries aspect and appearance of brown color is determined by anthocyans and polyphenols degradation and brown compounds formation.

  8. Infrared Spectra and Chemical Abundance of Methyl Propionate in Icy Astrochemical Conditions

    CERN Document Server

    Sivaraman, B; Das, A; Gopakumar, G; Majumdar, L; Chakrabarti, S K; Subramanian, K P; Sekhar, B N Raja; Hada, M

    2014-01-01

    We carried out an experiment in order to obtain the InfraRed (IR) spectra of methyl propionate (CH3CH2COOCH3) in astrochemical conditions and present the IR spectra for future identification of this molecule in the InterStellar Medium (ISM). The experimental IR spectrum is compared with the theoretical spectrum and an attempt was made to assign the observed peak positions to their corresponding molecular vibrations in condensed phase. Moreover, our calculations suggest that methyl propionate must be synthesized efficiently within the complex chemical network of the ISM and therefore be present in cold dust grains, awaiting identification.

  9. Assessment of existing H2/O2 chemical reaction mechanisms at reheat gas turbine conditions

    CERN Document Server

    Weydahl, Torleif; Seljeskog, Morten; Haugen, Nils Erland L

    2011-01-01

    This paper provides detailed comparisons of chemical reaction mechanisms of H2 applicable at high preheat temperatures and pressures relevant to gas turbine and particularly Alstom's reheat gas turbine conditions. It is shown that the available reaction mechanisms exhibit large differences in several important elementary reaction coefficients. The reaction mechanisms are assessed by comparing ignition delay and laminar flame speed results obtained from CHEMKIN with available data, however, the amount of data at these conditions is scarce and a recommended candidate among the mechanisms can presently not be selected. Generally, the results with the GRI-Mech and Leeds mechanisms deviate from the Davis, Li, O'Conaire, Konnov and San Diego mechanisms, but there are also significant deviations between the latter five mechanisms that altogether are better adapted to hydrogen. The differences in ignition delay times between the dedicated hydrogen mechanisms (O'Conaire, Li and Konnov) range from approximately a maxim...

  10. Define Project

    DEFF Research Database (Denmark)

    Munk-Madsen, Andreas

    2005-01-01

    "Project" is a key concept in IS management. The word is frequently used in textbooks and standards. Yet we seldom find a precise definition of the concept. This paper discusses how to define the concept of a project. The proposed definition covers both heavily formalized projects and informally...... organized, agile projects. Based on the proposed definition popular existing definitions are discussed....

  11. A general approach for defining the macroscopic free energy density of saturated porous media at finite strains under non-isothermal conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gajo, A. [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento, Via Mesiano 77 - 38050 Povo, Trento (Italy)

    2011-11-15

    A general approach is proposed for defining the macroscopic free energy density function (and its complement, the free enthalpy) of a saturated porous medium submitted to finite deformations under non-isothermal conditions, in the case of compressible fluid and solid constituents. Reference is made to an elementary volume treated as an 'open system', moving with the solid skeleton. The proposed free energy depends on the generalised strains (namely an appropriate measure of the strain of the solid skeleton and the variation in fluid mass content) and the absolute temperatures of the solid and fluid phases (which are assumed to differ from each other for the sake of generality). This macroscopic energy proves to be a potential for the generalised stresses (namely the associated measure of the total stress and the free enthalpy of the pore fluid per unit mass) and the entropies of the solid and fluid phases. In contrast with mixture theories, the resulting free energy is not the simple sum of the free energies of the single constituents. Two simplified cases are examined in detail, i.e. the semi-linear theory (originally proposed for isothermal conditions and extended here to non-isothermal problems) and the linear theory. The proposed approach paves the way to the consistent non-isothermal-hyper-elastic-plastic modelling of saturated porous media with a compressible fluid and solid constituents. (authors)

  12. A general approach for defining the macroscopic free energy density of saturated porous media at finite strains under non-isothermal conditions

    International Nuclear Information System (INIS)

    A general approach is proposed for defining the macroscopic free energy density function (and its complement, the free enthalpy) of a saturated porous medium submitted to finite deformations under non-isothermal conditions, in the case of compressible fluid and solid constituents. Reference is made to an elementary volume treated as an 'open system', moving with the solid skeleton. The proposed free energy depends on the generalised strains (namely an appropriate measure of the strain of the solid skeleton and the variation in fluid mass content) and the absolute temperatures of the solid and fluid phases (which are assumed to differ from each other for the sake of generality). This macroscopic energy proves to be a potential for the generalised stresses (namely the associated measure of the total stress and the free enthalpy of the pore fluid per unit mass) and the entropies of the solid and fluid phases. In contrast with mixture theories, the resulting free energy is not the simple sum of the free energies of the single constituents. Two simplified cases are examined in detail, i.e. the semi-linear theory (originally proposed for isothermal conditions and extended here to non-isothermal problems) and the linear theory. The proposed approach paves the way to the consistent non-isothermal-hyper-elastic-plastic modelling of saturated porous media with a compressible fluid and solid constituents. (authors)

  13. Combined Micro-chemical and Micro-structural Analysis of New Minerals Representing Extreme Conditions

    Science.gov (United States)

    Ma, C.; Tschauner, O. D.

    2015-12-01

    Recent improvements in micro-chemical analysis in combination with novel tools for micrometer-scale structural analysis of minerals from synchrotron X-ray diffraction open a pathway towards studies of mineral paragenesis that were previously not or barely accessible. Often mineral assemblies that represent extreme conditions also pose extreme challenges to analysis: very small size scale, complex matrix, minor amounts of material. Examples of such extreme, but also quite relevant environments are: a) High pressure shock-metamorphic minerals in meteorites and terrestrial impact sites, b) inclusions in diamonds from the deep mantle, c) ultrarefractory phases in Ca-Al-inlcusions from the solar nebula, d) presolar condensates. We show how a combination of synchrotron-based structural and semi-quantitative chemical techniques, with electron-microscopy based high-resolution imaging and fully quantitative chemical analysis and qualitative structural identification establish a powerful tool for discovery and characterization of important and interesting new minerals on micron- to submicron size scale.

  14. Combined physical and chemical methods to control lesser mealworm beetles under laboratory conditions.

    Science.gov (United States)

    Wolf, Jônatas; Potrich, Michele; Lozano, Everton R; Gouvea, Alfredo; Pegorini, Carla S

    2015-06-01

    The lesser mealworm beetle, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), is an important insect pest. The insect acts as a disease vector and reservoir, negatively affecting the health of birds and humans, and harming poultry husbandry. Controlling the lesser mealworm is generally based on using synthetic chemical insecticides, which are sometimes ineffective, and is limited due to market concerns regarding the toxicity of chemical residues in food products. In this context, the present study aimed to evaluate the potential for the combination of physical and chemical methods to control A. diaperinus. Bioassays were conducted using poultry bedding and known populations of beetle adults and larvae. The treatments consisted of the isolated application of 400 g/m2 hydrated lime; 20% added moisture (distilled water); temperature increase to 45°C; an insecticide composed of cypermethrin, chlorpyrifos, and citronellal; and a combination of these factors. Beetle mortality was measured at 7 and 10 d of treatment. The hydrated lime and moisture treatments alone did not control A. diaperinus. Raising the temperature of the poultry bedding to 45°C effectively controlled both larvae (90±6%) and adults (90±4%). The use of insecticide provided adequate control of A. diaperinus in the conditions of the bioassay (93±2% and 68±5% for adults and larvae, respectively). The combination of the studied factors led to the total control of larvae and adults after 7 d of treatment. PMID:25834245

  15. Physico-chemical characterization of steel slag. Study of its behavior under simulated environmental conditions.

    Science.gov (United States)

    Navarro, Carla; Díaz, Mario; Villa-García, María A

    2010-07-15

    The chemical and mineralogical composition of steel slag produced in two ArcelorMittal steel plants located in the North of Spain, as well as the study of the influence of simulated environmental conditions on the properties of the slag stored in disposal areas, was carried out by elemental chemical analysis, XRF, X-ray diffraction, thermal analysis, and scanning electron microscopy with EDS analyzer. Spectroscopic characterization of the slag was also performed by using FTIR spectroscopy. Due to the potential uses of the slag as low cost adsorbent for water treatment and pollutants removal, its detailed textural characterization was carried out by nitrogen adsorption-desorption at 77 K and mercury intrusion porosimetry. The results show that the slag is a crystalline heterogeneous material whose main components are iron oxides, calcium (magnesium) compounds (hydroxide, oxide, silicates, and carbonate), elemental iron, and quartz. The slags are porous materials with specific surface area of 11 m(2)g(-1), containing both mesopores and macropores. Slag exposure to simulated environmental conditions lead to the formation of carbonate phases. Carbonation reduces the leaching of alkaline earth elements as well as the release of the harmful trace elements Cr (VI) and V. Steel slags with high contents of portlandite and calcium silicates are potential raw materials for CO(2) long-term storage. PMID:20568743

  16. Variable Impact on Mortality of AIDS-Defining Events Diagnosed during Combination Antiretroviral Therapy: Not All AIDS-Defining Conditions Are Created Equal Antiretroviral Therapy Cohort Collaboration (ART-CC)

    NARCIS (Netherlands)

    A. Mocroft; J.A.C. Sterne; M. Egger; M. May; S. Grabar; H. Furrer; C. Sabin; G. Fatkenheuer; A. Justice; P. Reiss; A.d.A. Monforte; J. Gill; R. Hogg; F. Bonnet; M. Kitahata; S. Staszewski; J. Casabona; R. Harris; M. Saag

    2009-01-01

    Background. The extent to which mortality differs following individual acquired immunodeficiency syndrome (AIDS)-defining events (ADEs) has not been assessed among patients initiating combination antiretroviral therapy. Methods. We analyzed data from 31,620 patients with no prior ADEs who started co

  17. An evaluation of the chemical, radiological, and ecological conditions of West Lake on the Hanford site

    International Nuclear Information System (INIS)

    West Lake and its immediate surrounding basin represent a unique habitat that is dominated by highly saline water and soil. The basin offers a valuable research site for studies of a rare and complex wetland area in the desert. This report is an evaluation of the chemical, radiological, and ecological conditions at West Lake and describes how ground water influences site properties. The scope of this evaluation consisted of a sampling program in 1989 and a review of data from the perspective of assessing the impact of Hanford Site operations on the physical, chemical, and ecological conditions of West Lake and its surrounding basin. The water level in West Lake fluctuates in relation to changes in the water table. The connection between West Lake and ground water is also supported by the presence of 3H and 99Tc in the ground water and in the lake. There are relatively high concentrations of uranium in West Lake; the highest concentrations are found in the northernmost isolated pool. Analyses of water, sediment, vegetation, and soil indicate possible shifts of isotropic ratios that indicate a reduction of 235U. Uranium-236 was not detected in West Lake water; its presence would indicate neutron-activated 235U from fuel reprocessing at Hanford. Trace metals are found at elevated concentrations in West Lake. Arsenic, chromium, copper, and zinc were found at levels in excess of US Environmental Protection Agency water quality criteria. Levels of radiological and chemical contamination in the West Lake basin are relatively low. Concentrations of fission isotopes exceed those that could be explained by atmospheric fallout, but fall short of action levels for active waste management areas. 31 refs., 8 figs., 18 tabs

  18. Characterizing summertime chemical boundary conditions for airmasses entering the US West Coast

    Directory of Open Access Journals (Sweden)

    G. G. Pfister

    2011-02-01

    Full Text Available The objective of this study is to analyze the pollution inflow into California during summertime and how it impacts surface air quality through combined analysis of a suite of observations and global and regional models. The focus is on the transpacific pollution transport investigated by the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission in June 2008. Additional observations include satellite retrievals of carbon monoxide and ozone by the EOS Aura Tropospheric Emissions Spectrometer (TES, aircraft measurements from the MOZAIC program and ozonesondes. We compare chemical boundary conditions (BC from the MOZART-4 global model, which are commonly used in regional simulations, with measured concentrations to quantify both the accuracy of the model results and the variability in pollution inflow. Both observations and model reflect a large variability in pollution inflow on temporal and spatial scales, but the global model captures only about half of the observed free tropospheric variability. Model tracer contributions show a large contribution from Asian emissions in the inflow. Recirculation of local US pollution can impact chemical BC, emphasizing the importance of consistency between the global model simulations used for BC and the regional model in terms of emissions, chemistry and transport. Aircraft measurements in the free troposphere over California show similar concentration ranges, variability and source contributions as free tropospheric air masses over ocean, but caution has to be taken that local pollution aloft is not misinterpreted as inflow. A flight route specifically designed to sample boundary conditions during ARCTAS-CARB showed a prevalence of plumes transported from Asia and thus may not be fully representative for average inflow conditions. Sensitivity simulations with a regional model with altered BCs show that the temporal variability in the pollution inflow does

  19. Characterizing summertime chemical boundary conditions for airmasses entering the US West Coast

    Directory of Open Access Journals (Sweden)

    G. G. Pfister

    2010-11-01

    Full Text Available The objective of this study is to analyze the pollution inflow into California during summertime and how it impacts surface air quality through combined analysis of a suite of observations and global and regional models. The focus is on the transpacific pollution transport investigated by the NASA Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS mission in June 2008. Additional observations include satellite retrievals of carbon monoxide and ozone by the EOS Aura Tropospheric Emissions Spectrometer (TES, aircraft measurements from the MOZAIC program and ozonesondes. We compare chemical boundary conditions (BC from the MOZART-4 global model, which are commonly used in regional simulations, with measured concentrations to quantify both the accuracy of the model results and the variability in pollution inflow. Both observations and model reflect a large variability in pollution inflow on temporal and spatial scales, but the global model captures only about half of the observed free tropospheric variability. Model tracer contributions show a large contribution from Asian emissions in the inflow. Recirculation of local US pollution can impact chemical BC, emphasizing the importance of consistency between the global model simulations used for BC and the regional model in terms of emissions, chemistry and transport. Aircraft measurements in the free troposphere over California show similar concentration range, variability and source contributions as free tropospheric air masses over ocean, but caution has to be taken that local pollution aloft is not misinterpreted as inflow. A flight route specifically designed to sample boundary conditions during ARCTAS-CARB showed a prevalence of plumes transported from Asia and thus may not be fully representative for average inflow conditions. Sensitivity simulations with a regional model with altered BCs show that the temporal variability in the pollution inflow does

  20. Chemical resilience of clay rich barrier materials to redox-oscillating conditions and implications for contaminant mobility

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. The mineralogical composition of argillaceous barrier materials is often considered to be static, and therefore, that interactions with contaminants and nutrients may be well constrained. Typically, solid/aqueous partition coefficients (Kd values) are obtained empirically to determine the proportion of contaminant immobilised by the solid phase for individual barrier material/contaminant combinations at defined contaminant loadings and pH. These values may then be used as indicators of potential contaminant mobility around waste storage facilities following the eventual failure of engineered barriers (1). While Kd values are a useful tool to modellers estimating contaminant mobility through porous media at thermodynamic equilibrium, over time and under dynamic biogeochemical conditions, matrix mineralogy, and therefore Kd values, are liable to change (2). Near surface environments implicated in back-filled or excavated storage solutions, currently proposed for low-level long-lived waste (LL-LLW), will result in more dynamic redox conditions than those predicted in deep, anoxic geological storage conditions (2). Such dynamic conditions are similar to those experienced in pluvial, fluvial or phreatic influenced soils and are likely to be far from thermodynamic equilibrium (3). Cyclic redox conditions of varying periodicity are likely to occur around near surface repositories due to a combination of microbial activity and variations in substrate saturation caused by changes to groundwater level and rates of pluvial infiltration. Upon saturation of near surface substrates reducing conditions occur rapidly due to slow inward diffusion of oxygen from the surface and rapid oxygen consumption by aerobic heterotrophic bacteria gaining energy from the mineralisation of organic matter (4, 5). Subsequent to the exhaustion of residual oxygen, anaerobic metabolism dominates in such environments resulting in the depletion of

  1. Defining Dyslexia

    Science.gov (United States)

    Tunmer, William; Greaney, Keith

    2010-01-01

    In 2007, the New Zealand Ministry of Education formally recognized the condition of dyslexia for the first time and has subsequently developed a working definition of the condition. The aim of this article is to draw on contemporary theory and research on reading development, reading difficulties, and reading intervention to describe what the…

  2. Historically defined autobiographical periods

    DEFF Research Database (Denmark)

    Brown, Norman R.; Hansen, Tia G. B.; Lee, Peter J.;

    2012-01-01

    The chapter reviews a research programme that has demonstrated the existence of historically defined autobiographical periods and identified the conditions that bring them about. Data from four samples of World War II-generation adults show that historically defined autobiographical periods endure...

  3. Defining Life

    Science.gov (United States)

    Benner, Steven A.

    2010-12-01

    Any definition is intricately connected to a theory that gives it meaning. Accordingly, this article discusses various definitions of life held in the astrobiology community by considering their connected "theories of life." These include certain "list" definitions and a popular definition that holds that life is a "self-sustaining chemical system capable of Darwinian evolution." We then act as "anthropologists," studying what scientists do to determine which definition-theories of life they constructively hold as they design missions to seek non-terran life. We also look at how constructive beliefs about biosignatures change as observational data accumulate. And we consider how a definition centered on Darwinian evolution might itself be forced to change as supra-Darwinian species emerge, including in our descendents, and consider the chances of our encountering supra-Darwinian species in our exploration of the Cosmos. Last, we ask what chemical structures might support Darwinian evolution universally; these structures might be universal biosignatures.

  4. Ca, Sr, O and D isotope approach to defining the chemical evolution of hydrothermal fluids: example from Long Valley, CA, USA

    Science.gov (United States)

    Brown, Shaun T.; Kennedy, B. Mack; DePaolo, Donald J.; Hurwitz, Shaul; Evans, William C.

    2013-01-01

    We present chemical and isotopic data for fluids, minerals and rocks from the Long Valley meteoric-hydrothermal system. The samples encompass the presumed hydrothermal upwelling zone in the west moat of the caldera, the Casa Diablo geothermal field, and a series of wells defining a nearly linear, ∼16 km long, west-to-east trend along the likely fluid flow path. Fluid samples were analyzed for the isotopes of water, Sr, and Ca, the concentrations of major cations and anions, alkalinity, and total CO2. Water isotope data conform to trends documented in earlier studies, interpreted as indicating a single hydrothermal fluid mixing with local groundwater. Sr isotopes show subtle changes along the flow path, which requires rapid fluid flow and minimal reaction between the channelized fluids and the wallrocks. Sr and O isotopes are used to calculate fracture spacing using a dual porosity model. Calculated fracture spacing and temperature data for hydrothermal fluids indicate the system is (approximately) at steady-state. Correlated variations among total CO2, and the concentration and isotopic composition of Ca suggest progressive fluid degassing (loss of CO2), which drives calcite precipitation as the fluid flows west-to-east and cools. The shifts in Ca isotopes require that calcite precipitated at temperatures of 150–180 °C is fractionated by ca. −0.3‰ to −0.5‰ relative to aqueous species. Our data are the first evidence that Ca isotopes undergo kinetic fractionation at high temperatures (>100 °C) and can be used to trace calcite precipitation along hydrothermal fluid flow paths.

  5. Interpopulational Variations in Sexual Chemical Signals of Iberian Wall Lizards May Allow Maximizing Signal Efficiency under Different Climatic Conditions.

    Directory of Open Access Journals (Sweden)

    José Martín

    Full Text Available Sexual signals used in intraspecific communication are expected to evolve to maximize efficacy under a given climatic condition. Thus, chemical secretions of lizards might evolve in the evolutionary time to ensure that signals are perfectly tuned to local humidity and temperature conditions affecting their volatility and therefore their persistence and transmission through the environment. We tested experimentally whether interpopulational altitudinal differences in chemical composition of femoral gland secretions of male Iberian wall lizards (Podarcis hispanicus have evolved to maximize efficacy of chemical signals in different environmental conditions. Chemical analyses first showed that the characteristics of chemical signals of male lizards differed between two populations inhabiting environments with different climatic conditions in spite of the fact that these two populations are closely related genetically. We also examined experimentally whether the temporal attenuation of the chemical stimuli depended on simulated climatic conditions. Thus, we used tongue-flick essays to test whether female lizards were able to detect male scent marks maintained under different conditions of temperature and humidity by chemosensory cues alone. Chemosensory tests showed that chemical signals of males had a lower efficacy (i.e. detectability and persistence when temperature and dryness increase, but that these effects were more detrimental for signals of the highest elevation population, which occupies naturally colder and more humid environments. We suggest that the abiotic environment may cause a selective pressure on the form and expression of sexual chemical signals. Therefore, interpopulational differences in chemical profiles of femoral secretions of male P. hispanicus lizards may reflect adaptation to maximize the efficacy of the chemical signal in different climates.

  6. Defining Life

    OpenAIRE

    Benner, Steven A.

    2010-01-01

    Any definition is intricately connected to a theory that gives it meaning. Accordingly, this article discusses various definitions of life held in the astrobiology community by considering their connected “theories of life.” These include certain “list” definitions and a popular definition that holds that life is a “self-sustaining chemical system capable of Darwinian evolution.” We then act as “anthropologists,” studying what scientists do to determine which definition-theories of life they ...

  7. Review and analysis of high temperature chemical reactions and the effect of non-equilibrium conditions

    Science.gov (United States)

    Johnson, R. E.

    1986-01-01

    Chemical reactions at high temperatures have been considered extensively because of their importance to the heating effects on re-entry of space vehicles. Data on these reactions however, are not abundant and even when found there are discrepancies in data collected by various investigators. In particular, data for recombination reactions are calculated from the dissociation reactions or vice versa through the equilibrium constant. This involves the use of the principle of detailed balancing. This principle is discussed in reference to conditions where it is valid as well as to those where it is not valid. Related topics that merit further study or for which applicable information was available are briefly mentioned in an appendix to this report.

  8. Chemical method of labelling proteins with the radionuclides of technetium at physiological condition

    International Nuclear Information System (INIS)

    A novel rapid chemical method of labeling plasma proteins, other compounds and/or substances containing protein with radionuclides of technetium such as sup(95m)Tc, sup(99m)Tc or sup(99)Tc at physiologic pH 7.4 condition, producing a sterile non-pyrogenic radioactive tracer material suitable for biological and medical uses. These radiolabeled protein substances are not denatured by the labeling process but retain their natural physiological and immunological properties. This novel labeling technique provides a simple and rapid means of labeling plasma proteins such as human serum albumin, fibrinogen, antibodies, hormones and enzymes with sup(95m)Tc or sup(99m)Tc for scintigraphic imaging which may allow visualization of thrombi, emboli, myocardial infarcts, infectious lesions or tumors

  9. Technical Note: Quantification of interferences of wet chemical HONO LOPAP measurements under simulated polar conditions

    Directory of Open Access Journals (Sweden)

    J. Kleffmann

    2008-11-01

    Full Text Available In the present pilot study, an optimized LOPAP instrument (LOng Path Absorption Photometer for the detection of nitrous acid (HONO in the atmosphere (DL 0.2 pptV was tested at the high alpine research station Jungfraujoch at 3580 m altitude in the Swiss Alps under conditions comparable to polar regions. HONO concentrations in the range <0.5–50 pptV with an average of 7.5 pptV were observed at the Jungfraujoch. The diurnal profiles obtained exhibited clear maxima at noon and minima with very low concentration during the night supporting the proposed photochemical production of HONO. In good agreement with recent measurements at the South Pole, it was demonstrated, that interferences of chemical HONO instruments can significantly influence the measurements and lead to considerable overestimations, especially for low pollution level. Accordingly, the active correction of interferences is of paramount importance for the determination of reliable HONO data.

  10. Efficient and selective chemical transformations under flow conditions: The combination of supported catalysts and supercritical fluids

    Directory of Open Access Journals (Sweden)

    M. Isabel Burguete

    2011-09-01

    Full Text Available This paper reviews the current trends in the combined use of supported catalytic systems, either on solid supports or in liquid phases and supercritical fluids (scFs, to develop selective and enantioselective chemical transformations under continuous and semi-continuous flow conditions. The results presented have been selected to highlight how the combined use of those two elements can contribute to: (i Significant improvements in productivity as a result of the enhanced diffusion of substrates and reagents through the interfaces favored by the scF phase; (ii the long term stability of the catalytic systems, which also contributes to the improvement of the final productivity, as the use of an appropriate immobilization strategy facilitates catalyst isolation and reuse; (iii the development of highly efficient selective or, when applicable, enantioselective chemical transformations. Although the examples reported in the literature and considered in this review are currently confined to a limited number of fields, a significant development in this area can be envisaged for the near future due to the clear advantages of these systems over the conventional ones.

  11. Optimization of wet lay-up conditions for steam generators hydrazine chemical treatment

    International Nuclear Information System (INIS)

    Since a long time, hydrazine is used as a chemical agent to prevent corrosion of unalloyed steels. This is a conventional treatment widely used by nuclear power plant operators. But its application in SG lay-up at French nuclear power plants has, however, lead to some drawbacks. Effluent releases: Due to regulation relative to release of hydrazine and alkaline chemical compounds, some plant operators limit the concentrations of reagents to levels that could lead to insufficient protection of materials. Safety hazards associated with SG nitrogen blanketing: Prohibiting use of nitrogen blankets for SG wet lay-up due to associated safety hazards could likewise jeopardize corrosion protection at normally specified hydrazine levels. As the exact limits of hydrazine action against corrosion during SG lay-up are not well known, it is sometimes difficult to evaluate the risk associated to low dosage of N2H4. In order to answer to these problems, Framatome ANP (France) decided to carry out a test program aimed to determine the limit conditions for use of hydrazine in a wet lay-up environment. (authors)

  12. Determination of chemical composition and shelf life of shad (Alosa tanaica Grimm, 1901 in refrigeration conditions

    Directory of Open Access Journals (Sweden)

    Hünkar Avni Duyar

    2012-01-01

    Full Text Available This study, was carried out to determine the shelf life and chemical composition of stored shad (Alosa tanaica Grimm, 1901 in refrigerator conditions (4 ±0.5° C. Crude fat, crude ash, crude protein and moisture were 13 ±0.5%, 1.3 ±0.4%, 17 ±0.2%, 68 ±0.6% at the begining of the fresh shad, respectively. The quality of shad fish during storage were evaluated by pH, TVB-N, TBA, sensory and microbiological analysis. According to the results of sensory analysis, be-ginning to lose the consumability property after the 4th day and inconsumable at 7th day of sto¬red shad fish were determined by panelists. As a result of chemical analysis the amount of TVB-N at 0. day 7.4 ± 0.1 mg/100g and 7th day of stored was determined 37.2 ±0.4 mg/100 g, TBA value at 0. days 2.15 ± 0.3 mg /kg MDA and 7. day 15.22 ± 0.9 mg /kg determined as malondialdehyde, the pH value at 6. day was 7.3 respectively. Made as a result of microbiolo-gical analysis of bacterial load at 0. day 0.47 ± 0.09 log CFU /g and 6. day 6.3 ± 0.1 log CFU/g, respectively, and consumption was found to exceed the limit value. In a survey of con-ditions as a result of the refrigerator (4 ± 0.5°C to maintain the shad (Alosa tanaica Grimm, 1901, the shelf life of 6 days.

  13. Physical and chemical stability of expired fixed dose combination artemether-lumefantrine in uncontrolled tropical conditions

    Directory of Open Access Journals (Sweden)

    Hess Kimberly

    2009-02-01

    Full Text Available Abstract Background New artemisinin combination therapies pose difficulties of implementation in developing and tropical settings because they have a short shelf-life (two years relative to the medicines they replace. This limits the reliability and cost of treatment, and the acceptability of this treatment to health care workers. A multi-pronged investigation was made into the chemical and physical stability of fixed dose combination artemether-lumefantrine (FDC-ALU stored under heterogeneous, uncontrolled African conditions, to probe if a shelf-life extension might be possible. Methods Seventy samples of expired FDC-ALU were collected from private pharmacies and malaria researchers in seven African countries. The samples were subjected to thin-layer chromatography (TLC, disintegration testing, and near infrared Raman spectrometry for ascertainment of active ingredients, tablet integrity, and chemical degradation of the tablet formulation including both active ingredients and excipients. Results Seventy samples of FDC-ALU were tested in July 2008, between one and 58 months post-expiry. 68 of 70 (97% samples passed TLC, disintegration and Raman spectrometry testing, including eight samples that were post-expiry by 20 months or longer. A weak linear association (R2 = 0.33 was observed between the age of samples and their state of degradation relative to brand-identical samples on Raman spectrometry. Sixty-eight samples were retested in February 2009 using Raman spectrometry, between eight and 65 months post-expiry. 66 of 68 (97% samples passed Raman spectrometry retesting. An unexpected observation about African drug logistics was made in three batches of FDC-ALU, which had been sold into the public sector at concessional pricing in accordance with a World Health Organization (WHO agreement, and which were illegally diverted to the private sector where they were sold for profit. Conclusion The data indicate that FDC-ALU is chemically and

  14. Molecules in interstellar clouds. [physical and chemical conditions of star formation and biological evolution

    Science.gov (United States)

    Irvine, W. M.; Hjalmarson, A.; Rydbeck, O. E. H.

    1981-01-01

    The physical conditions and chemical compositions of the gas in interstellar clouds are reviewed in light of the importance of interstellar clouds for star formation and the origin of life. The Orion A region is discussed as an example of a giant molecular cloud where massive stars are being formed, and it is pointed out that conditions in the core of the cloud, with a kinetic temperature of about 75 K and a density of 100,000-1,000,000 molecules/cu cm, may support gas phase ion-molecule chemistry. The Taurus Molecular Clouds are then considered as examples of cold, dark, relatively dense interstellar clouds which may be the birthplaces of solar-type stars and which have been found to contain the heaviest interstellar molecules yet discovered. The molecular species identified in each of these regions are tabulated, including such building blocks of biological monomers as H2O, NH3, H2CO, CO, H2S, CH3CN and H2, and more complex species such as HCOOCH3 and CH3CH2CN.

  15. Using capillary electrophoresis to study the chemical conditions within cracks in aluminum alloys.

    Science.gov (United States)

    Cooper, K R; Kelly, R G

    1999-07-30

    The environment-assisted cracking (EAC) susceptibility of some aluminum alloys used for airplane structural components currently limits their use in the peak strength condition. Understanding the mechanism of EAC will facilitate the development of crack-resistant alloys with optimum mechanical properties. One component towards understanding the fundamental processes responsible for EAC is a comprehensive knowledge of the chemical conditions within cracks. The present work uses capillary electrophoresis (CE) to quantify the crack chemistry in order to provide insight into the nature of the mechanism controlling cracking. The highly restricted geometry of cracks in metals means that a crack typically contains less than 10 microliters of solution. The high mass sensitivity combined with the inherently robust nature of CE makes it an ideal analytical technique for this application. Complicating factors in the accurate determination of the crack environment include high levels of sodium present from the test solution. Low sample volume and analyte matrix complexity necessitated the development of specific sampling, extraction and analysis methods. Analysis of the crack solutions in EAC-susceptible material revealed high levels of Al3+, Mg2+, Zn2+, and Cl- near the crack tip. Cations arise from the anodic dissolution of the alloy, whereas chloride ingress from the external environment occurs to maintain solution electroneutrality within the crack. In contrast, EAC-resistant material exhibited significantly lower concentrations of dissolution products. PMID:10457501

  16. Dimethylglycine and chemically related amines tested for mutagenicity under potential nitrosation conditions.

    Science.gov (United States)

    Hoorn, A J

    1989-04-01

    Dimethylglycine (DMG) and the chemically related amino acids glycine, sarcosine (monomethylglycine) and betaine (trimethylglycine) were tested in Salmonella typhimurium strain TA100 after treatment with sodium nitrite under acidic conditions using a modified Ames Salmonella/microsome assay as reported by Colman et al. (1980). The increase in the number of revertants observed both with and without metabolic activation was also induced in the control mixtures without adding the amines. From the subsequent testing of the individual components of the mixtures, we concluded that non-consumed nitrite was responsible for the mutagenic responses observed in the different reaction mixtures, and not the amines themselves. There were no consistent indications of mutagenic activity of the DMG test mixture as compared to the control mixture which exhibited both consistent mutagenic activity and a toxic effect which was not increased by the addition of DMG. In fact, DMG seemed to decrease the toxicity of the control reaction solution to the Salmonella which was clearly observed at the higher doses. DMG cannot be considered mutagenic under the test conditions employed. The same can be said of the other amino acids as well. PMID:2468082

  17. Surface Cleaning or Activation?Control of Surface Condition Prior to Thermo-Chemical Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    Brigitte Haase; Juan Dong; Jens Heinlein

    2004-01-01

    Actual heat treatment processes must face increasing specifications with reference to process quality, safety and results in terms of reproducibility and repeatability. They can be met only if the parts' surface condition is controlled during manufacturing and, especially, prior to the treatment. An electrochemical method for the detection of a steel part's surface condition is presented, together with results, consequences, and mechanisms concerning surface pre-treatment before the thermochemical process. A steel surface's activity or passivity can be detected electrochemically, independently from the chemical background. The selected method was the recording of potential vs. time curves at small constant currents, using a miniaturized electrochemical cell, a (nearly) non-destructive electrolyte and a potentio-galvanostatic setup. The method enables to distinguish types of surface contamination which do not interfere with the thermochemical process, from passive layers which do and must be removed. Whereas some types of passive layers can be removed using conventional cleaning processes and agents, others are so stable that their effects can only be overcome by applying an additional activation pre-treatment, e.g. oxynitriding.

  18. Defining conditions where long-term glucocorticoid treatment has an acceptably low level of harm to facilitate implementation of existing recommendations: viewpoints from an EULAR task force.

    Science.gov (United States)

    Strehl, Cindy; Bijlsma, Johannes W J; de Wit, Maarten; Boers, Maarten; Caeyers, Nele; Cutolo, Maurizio; Dasgupta, Bhaskar; Dixon, William G; Geenen, Rinie; Huizinga, Tom W J; Kent, Alison; de Thurah, Annette Ladefoged; Listing, Joachim; Mariette, Xavier; Ray, David W; Scherer, Hans U; Seror, Raphaèle; Spies, Cornelia M; Tarp, Simon; Wiek, Dieter; Winthrop, Kevin L; Buttgereit, Frank

    2016-06-01

    There is convincing evidence for the known and unambiguously accepted beneficial effects of glucocorticoids at low dosages. However, the implementation of existing recommendations and guidelines on the management of glucocorticoid therapy in rheumatic diseases is lagging behind. As a first step to improve implementation, we aimed at defining conditions under which long-term glucocorticoid therapy may have an acceptably low level of harm. A multidisciplinary European League Against Rheumatism task force group of experts including patients with rheumatic diseases was assembled. After a systematic literature search, breakout groups critically reviewed the evidence on the four most worrisome adverse effects of glucocorticoid therapy (osteoporosis, hyperglycaemia/diabetes mellitus, cardiovascular diseases and infections) and presented their results to the other group members following a structured questionnaire for final discussion and consensus finding. Robust evidence on the risk of harm of long-term glucocorticoid therapy was often lacking since relevant study results were often either missing, contradictory or carried a high risk of bias. The group agreed that the risk of harm is low for the majority of patients at long-term dosages of ≤5 mg prednisone equivalent per day, whereas at dosages of >10 mg/day the risk of harm is elevated. At dosages between >5 and ≤10 mg/day, patient-specific characteristics (protective and risk factors) determine the risk of harm. The level of harm of glucocorticoids depends on both dose and patient-specific parameters. General and glucocorticoid-associated risk factors and protective factors such as a healthy lifestyle should be taken into account when evaluating the actual and future risk. PMID:26933146

  19. Electric Current Activated Combustion Synthesis and Chemical Ovens Under Terrestrial and Reduced Gravity Conditions

    Science.gov (United States)

    Unuvar, C.; Fredrick, D.; Anselmi-Tamburini, U.; Manerbino, A.; Guigne, J. Y.; Munir, Z. A.; Shaw, B. D.

    2004-01-01

    Combustion synthesis (CS) generally involves mixing reactants together (e.g., metal powders) and igniting the mixture. Typically, a reaction wave will pass through the sample. In field activated combustion synthesis (FACS), the addition of an electric field has a marked effect on the dynamics of wave propagation and on the nature, composition, and homogeneity of the product as well as capillary flow, mass-transport in porous media, and Marangoni flows, which are influenced by gravity. The objective is to understand the role of an electric field in CS reactions under conditions where gravity-related effects are suppressed or altered. The systems being studied are Ti+Al and Ti+3Al. Two different ignition orientations have been used to observe effects of gravity when one of the reactants becomes molten. This consequentially influences the position and concentration of the electric current, which in turn influences the entire process. Experiments have also been performed in microgravity conditions. This process has been named Microgravity Field Activated Combustion Synthesis (MFACS). Effects of gravity have been demonstrated, where the reaction wave temperature and velocity demonstrate considerable differences besides the changes of combustion mechanisms with the different high currents applied. Also the threshold for the formation of a stable reaction wave is increased under zero gravity conditions. Electric current was also utilized with a chemical oven technique, where inserts of aluminum with minute amounts of tungsten and tantalum were used to allow observation of effects of settling of the higher density solid particles in liquid aluminum at the present temperature profile and wave velocity of the reaction.

  20. Chemical durability of lead borosilicate glass matrix under simulated geological conditions

    International Nuclear Information System (INIS)

    The lead borosilicate glass has been developed for vitrification of High Level Waste (HLW) stored at Trombay. This waste is contains especially high contents of sodium, uranium sulphate and iron. The glasses containing HLW are to be ultimately disposed into deep geological repositories. Long term leach rates under simulated geological conditions need to be evaluated for glass matrix. Studies were taken up to estimate the lead borosilicate glass WTR-62 matrix for chemical durability in presence of synthetic ground water. The leachant selected was based on composition of ground water sample near proposed repository site. In the first phase of these tests, the experiments were conducted for short duration of one and half month. The leaching experiments were conducted in presence of a) distilled water b) synthetic ground water c) synthetic ground water containing granite, bentonite and ferric oxide and d) synthetic ground water containing humic acid at 1000C. The leachate samples were analysed by pHmetry , ion chromatography and UV -VIS spectrophotometry. The normalised leach rates for lead borosilicate WTR- 62 glass matrix based on silica, boron and sulphate analyses of leachates were of the order of 10-3 to 10-5 gms/cm2/day for 45 days test period in presence of synthetic ground water as well as in presence of other materials likely to be present along with synthetic ground water. These rates are comparable to those of sodium borsilicate glass matrices reported in literature. It is known that the leach rates of glass matrix decrease with longer test durations due to formation of leached layer on its surface. The observed leach rates of lead borosilicate WTR- 62 glass matrix for 45 day tests under simulated geological conditions were found to be sufficiently encouraging to take up long term tests for evaluating its performances under repository conditions. (author)

  1. Phytoplankton communities of polar regions--Diversity depending on environmental conditions and chemical anthropopressure.

    Science.gov (United States)

    Kosek, Klaudia; Polkowska, Żaneta; Żyszka, Beata; Lipok, Jacek

    2016-04-15

    The polar regions (Arctic and Antarctic) constitute up to 14% of the biosphere and offer some of the coldest and most arid Earth's environments. Nevertheless several oxygenic phototrophs including some higher plants, mosses, lichens, various algal groups and cyanobacteria, survive that harsh climate and create the base of the trophic relationships in fragile ecosystems of polar environments. Ecosystems in polar regions are characterized by low primary productivity and slow growth rates, therefore they are more vulnerable to disturbance, than those in temperate regions. From this reason, chemical contaminants influencing the growth of photoautotrophic producers might induce serious disorders in the integrity of polar ecosystems. However, for a long time these areas were believed to be free of chemical contamination, and relatively protected from widespread anthropogenic pressure, due their remoteness and extreme climate conditions. Nowadays, there is a growing amount of data that prove that xenobiotics are transported thousands of kilometers by the air and ocean currents and then they are deposed in colder regions and accumulate in many environments, including the habitats of marine and freshwater cyanobacteria. Cyanobacteria (blue green algae), as a natural part of phytoplankton assemblages, are globally distributed, but in high polar ecosystems they represent the dominant primary producers. These microorganisms are continuously exposed to various concentration levels of the compounds that are present in their habitats and act as nourishment or the factors influencing the growth and development of cyanobacteria in other way. The most common group of contaminants in Arctic and Antarctic are persistent organic pollutants (POPs), characterized by durability and resistance to degradation. It is important to determine their concentrations in all phytoplankton species cells and in their environment to get to know the possibility of contaminants to transfer to higher

  2. Effects of dehulling and storage conditions on cooking requirements and chemical composition of soybeans.

    Science.gov (United States)

    Cabral, L C; Serna-Saldivar, S O; Tinsley, A M

    1995-03-01

    Changes in cooking requirements and chemical composition of whole and dehulled soybeans, stored in 2 different environments [25 degrees C /75% R.H. (Environment 1) and 38 degrees C /90% R.H. (Environment 2)], were studied. Rate of water absorption and solid losses during cooking were higher for the dehulled soybeans at both storage conditions. However, cooking requirements to achieve the same degree of texture in the cotyledons were similar for whole and dehulled seeds. Cooking time increased with prolonged storage; the effect was more noticeable in samples stored under Environment 2. Samples kept for 6 months required almost twice as much cooking than control samples. Dehulled soybeans had a lower fiber content, relatively higher amounts of protein and fat, but similar amino acid compositions than whole soybeans. Cooking caused losses of carbohydrates and ash and, therefore, significantly increased levels of protein and fat reflected by losses of solids during soaking and cooking. Among the amino acids, only cysteine suffered substantial decrease as a result of cooking. Cooking and storage inactivated 99% and from 20-35% of the trypsin inhibitors, respectively; the latter effect was more accentuated in samples stored under Environment 2. PMID:8729250

  3. Extent of hydrogen coverage of Si(001) under chemical vapor deposition conditions from ab initio approaches

    Science.gov (United States)

    Rosenow, Phil; Tonner, Ralf

    2016-05-01

    The extent of hydrogen coverage of the Si(001) c(4 × 2) surface in the presence of hydrogen gas has been studied with dispersion corrected density functional theory. Electronic energy contributions are well described using a hybrid functional. The temperature dependence of the coverage in thermodynamic equilibrium was studied computing the phonon spectrum in a supercell approach. As an approximation to these demanding computations, an interpolated phonon approach was found to give comparable accuracy. The simpler ab initio thermodynamic approach is not accurate enough for the system studied, even if corrections by the Einstein model for surface vibrations are considered. The on-set of H2 desorption from the fully hydrogenated surface is predicted to occur at temperatures around 750 K. Strong changes in hydrogen coverage are found between 1000 and 1200 K in good agreement with previous reflectance anisotropy spectroscopy experiments. These findings allow a rational choice for the surface state in the computational treatment of chemical reactions under typical metal organic vapor phase epitaxy conditions on Si(001).

  4. Phase transition and chemical decomposition of liquid carbon dioxide and nitrogen mixture under extreme conditions

    Science.gov (United States)

    Xiao-Xu, Jiang; Guan-Yu, Chen; Yu-Tong, Li; Xin-Lu, Cheng; Cui-Ming, Tang

    2016-02-01

    Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen (CO2-N2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic (QMD) simulations based on density functional theory including dispersion corrections (DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm3 to 3.40 g/cm3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO2-N2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions (PCFs) and the distribution of various molecular components. The insulator-metal transition is demonstrated by means of the electronic density of states (DOS). Project supported by the National Natural Science Foundation of China (Grant Nos. 11374217, 11135012, and 11375262) and the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11176020).

  5. Chemical and mineralogical aspects of water-bentonite interaction in nuclear fuel disposal conditions

    International Nuclear Information System (INIS)

    In the field of nuclear fuel disposal, bentonite has been selected as the principal sealing and buffer material for placement around waste canisters, forming both a mechanical and chemical barrier between the radioactive waste and the surrounding ground water. Ion exchange and mineral alteration processes were investigated in a laboratory study of the long-term interaction between compacted Na-bentonite (Volclay MX-80) and ground water solutions, conducted under simulated nuclear fuel disposal conditions. The possible alteration of montmorillonite into illite has been a major object of the mineralogical study. However, no analytical evidence was found, that would indicate the formation of this non-expandable clay type. Apparently, the change of montmorillonite from Na- to Ca-rich was found to be the major alteration process in bentonite. In the water, a concentration decrease in Ca, Mg, and K, and an increase in Na, HCO3 and SO4 were recorded. The amount of calcium ions available in the water was considered insufficient to account for the recorded formation of Ca-montmorillonite. It is therefore assumed that the accessory Ca-bearing minerals in bentonite provide the fundamental source of these cations, which exchange with sodium during the alteration process. (38 refs.)

  6. Chemical transition of nitrate ions accompanied with corrosion of carbon steel under alkaline conditions

    International Nuclear Information System (INIS)

    Carbon steel was immersed in an aqueous solution of NaNO3 in a closed system for observing both the chemical interaction between metal and NO3-, and the effect of nitrate on the generation rate of H2 gas. The experimental pH range of the solution was 10.0-13.5 which corresponds to that of pore fluid in cementitious material. The cathodic current density showed a 'Tafel equation type' potential dependency in aqueous solution containing NO3- or NO2-. In spite of the accelerated cathodic reaction due to the existence of nitrate, the corrosion rate of carbon steel was not accelerated in the nitrate solutions. This fact suggests that the system is controlled by the anodic reaction. The nitrate reduction accompanied by the corrosion of carbon steel is considered to be a series reaction such as NO3-→NO2-→NH3. The nitrate reduction reaction competes with the water reduction reaction (hydrogen evolution reaction) within the anodic controlled condition, therefore nitrate strongly reduces the hydrogen generation rate (1/100-1/500 of the cases without nitrate in 1.0 mol dm-3 NaNO3 cases). The generation rates of NH3 were independent of the concentration of NO3- over the range of 1.0 x 10-3 - 1.0 mol dm-3. (author)

  7. [Influence of ancient glass samples surface conditions on chemical composition analysis using portable XRF].

    Science.gov (United States)

    Liu, Song; Li, Qing-hui; Gan, Fu-xi

    2011-07-01

    Portable X-ray fluorescence analysis (PXRF) is one kind of surface analysis techniques, and the sample surface condition is an important factor that influences the quantitative analysis results. The ancient glass samples studied in the present paper were excavated from Xinjiang, Guangxi, Jiangsu provinces, and they belong to Na2O-CaO-SiO2, K2O-SiO2, and PbO-BaO-SiO2 system, respectively. Quantitative analysis results of weathered surface and inside of the ancient glass samples were compared. The concentration change of main fluxes in different parts of the samples was pointed out. Meanwhile, the authors studied the effect of distance between the sample and the reference plane, and curve shape of the sample on the quantitative results. The results obtained were calibrated by three methods, and the validity of these three methods was proved. Finally, the normalizing method was proved to be a better method for quantitative analysis of antiques. This paper also has guiding significance for chemical composition analysis of ancient jade samples using PXRF. PMID:21942060

  8. Study on chemical buffering property of GMZ sodium bentonite under atmospheric condition

    International Nuclear Information System (INIS)

    At present, the deep geological disposal is regarded as the most reasonable and effective way to safely disposal the high-level radioactive wastes in the world. The conceptual model of HLW geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the engineered barrier materials and GMZ Na-bentonite is selected as the basic material. One of the most important functions related to buffer is the chemical buffering, which means buffering the changes in pore water chemistry. This paper presents the experiments of GMZ-1 Na-bentonite reacted with distilled water under atmospheric condition. The batch tests and results discussion are reported. Na and Mg in batch test solution are co-provided by interlayer cations of montmorillonite and solids dissolution, K and Ca are provided by dissolution of solids. The result is a pre-requisite for predicting near-field nuclide migration and assesses the long-term stability of the engineered barrier materials. (author)

  9. Quantitative and qualitative shifts in defensive metabolites define chemical defense investment during leaf development in Inga, a genus of tropical trees.

    Science.gov (United States)

    Wiggins, Natasha L; Forrister, Dale L; Endara, María-José; Coley, Phyllis D; Kursar, Thomas A

    2016-01-01

    Selective pressures imposed by herbivores are often positively correlated with investments that plants make in defense. Research based on the framework of an evolutionary arms race has improved our understanding of why the amount and types of defenses differ between plant species. However, plant species are exposed to different selective pressures during the life of a leaf, such that expanding leaves suffer more damage from herbivores and pathogens than mature leaves. We hypothesize that this differential selective pressure may result in contrasting quantitative and qualitative defense investment in plants exposed to natural selective pressures in the field. To characterize shifts in chemical defenses, we chose six species of Inga, a speciose Neotropical tree genus. Focal species represent diverse chemical, morphological, and developmental defense traits and were collected from a single site in the Amazonian rainforest. Chemical defenses were measured gravimetrically and by characterizing the metabolome of expanding and mature leaves. Quantitative investment in phenolics plus saponins, the major classes of chemical defenses identified in Inga, was greater for expanding than mature leaves (46% and 24% of dry weight, respectively). This supports the theory that, because expanding leaves are under greater selective pressure from herbivores, they rely more upon chemical defense as an antiherbivore strategy than do mature leaves. Qualitatively, mature and expanding leaves were distinct and mature leaves contained more total and unique metabolites. Intraspecific variation was greater for mature leaves than expanding leaves, suggesting that leaf development is canalized. This study provides a snapshot of chemical defense investment in a speciose genus of tropical trees during the short, few-week period of leaf development. Exploring the metabolome through quantitative and qualitative profiling enables a more comprehensive examination of foliar chemical defense investment

  10. Growth process conditions of tungsten oxide thin films using hot-wire chemical vapor deposition

    International Nuclear Information System (INIS)

    Highlights: ► Process parameters to control hot-wire CVD of WO3−x are categorized. ► Growth time, oxygen partial pressure, filament and substrate temperature are varied. ► Chemical and crystal structure, optical bandgap and morphology are determined. ► Oxygen partial pressure determines the deposition rate up to as high as 36 μm min−1. ► Nanostructures, viz. wires, crystallites and closed crystallite films, are controllably deposited. - Abstract: We report the growth conditions of nanostructured tungsten oxide (WO3−x) thin films using hot-wire chemical vapor deposition (HWCVD). Two tungsten filaments were resistively heated to various temperatures and exposed to an air flow at various subatmospheric pressures. The oxygen partial pressure was varied from 6.0 × 10−6 to 1.0 mbar and the current through the filaments was varied from 4.0 to 9.0 A, which constitutes a filament temperature of 1390–2340 °C in vacuum. It is observed that the deposition rate of the films is predominantly determined by the oxygen partial pressure; it changes from about 1 to about 36,000 nm min−1 in the investigated range. Regardless of the oxygen partial pressure and filament temperature used, thin films with a nanogranular morphology are obtained, provided that the depositions last for 30 min or shorter. The films consist either of amorphous or partially crystallized WO3−x with high averaged transparencies of over 70% and an indirect optical band gap of 3.3 ± 0.1 eV. A prolonged deposition time entails an extended exposure of the films to thermal radiation from the filaments, which causes crystallization to monoclinic WO3 with diffraction maxima due to the (0 0 2), (2 0 0) and (0 2 0) crystallographic planes, furthermore the nanograins sinter and the films exhibit a cone-shaped growth. By simultaneously influencing the surface mobility, by heating the substrates to Tsurface = 700 ± 100 °C, and the deposition rate, a very good control of the morphology of the

  11. Chemical composition of fruits of a feijoa (F. sellowiana in the conditions of subtropics of russia

    Directory of Open Access Journals (Sweden)

    Oksana Belous

    2014-02-01

    Full Text Available The feijoa is culture quite widespread on the Black Sea coast of Russia. Difficulties are connected with absence in Russia of grades. All gardens have only the mix of grades, which is grown up from seeds. At institute are going of work on creation of productive varieties, with good quality parameters. Data on chemical and biochemical composition of fruits of high-yielding forms of a feijoa are provided in article. After carried-out selection work we selected a large number of perspective forms of a feijoa (more than 50. However not all of them was repeated by the results on productivity and were excluded from works on further studying. For today after rejection there were no more than two tens perspective forms.  They differ from each other on productivity, terms of maturing and quality of fruits. On efficiency the D-1 forms (Dagomys, 0-01 (Country and 10-22 are allocated - productivity of fruits (on the average in 7 years made respectively 33.3, 20.1 and 12.4 kg from a bush. The plants are sorted out according to the productivity, ripening terms and fruit quality. It is defined that early ripe grades are characterized by higher activity of oxidizing enzymes (263.1 mL.O2.g-1. In a zone of damp subtropics the grades containing increased quantity of carotinoids are steadier (0.31 mg.g-1. The contents in fruits of a feijoa of such substances, as vitamin P, Р-active and pectin substances, ascorbic acid, macro and microelements are revealed. Fruits of a feijoa are differed the increased accumulation of sugars, at some forms the content of sucrose prevails over amount of monosaccharide. High accumulation of vitamin C (41.89 - 78.68 mg.dL-1 is noted. But we don't confirm the high content of iodine in fruits. Fruits of a feijoa can be considered as potential raw materials for production of canned products with a functional purpose.

  12. Combined chemical and EIS study of the reaction of zinc coatings under alkaline conditions

    International Nuclear Information System (INIS)

    Graphical abstract: - Highlights: • An electrochemical unit for automatic EIS and pH modulation is used. • ZnMg2Al2 and ZnAl53 are studied in alkaline solutions. • Amount of consumed sodium hydroxide allows following hydroxide formation and film thickness. • Cross sections of 13 μm show excellent agreement with consumed hydroxide. • ZnAl53 consumes more hydroxide due to soluble aluminate formation. - Abstract: Two different zinc coatings of composition ZnMg2Al2 (Zn + 2 wt.% Mg + 2 wt.% Al) and ZnAl53 (Zn + 53 wt.% Al) were investigated in aqueous solution at pH 12.0 with a novel setup, the so-called impedance titrator. This device is able to perform electrochemical measurements including, but not limited to, impedance spectroscopy in dependency of different pH-values. The setup allows holding the pH-value with a precision of at least 0.05 by dosing the required amount of titrating agent to the system. If the alkaline pH region is investigated, hydroxide ions are consumed in the course of passive layer formation. The amount of consumed hydroxide allows to quantitatively follow the formation of the hydroxide film and its thickness. Cross section SEM shows an excellent agreement of 13 μm after 7 h for ZnMg2Al2. At a constant pH value, the hydroxide concentration is constant and film formation is well defined and kinetically characterised. The consumption of hydroxide by the ZnAl53 coating is higher resulting from the solubility of the Al as aluminate under alkaline conditions. The composition of the precipitates contains less than 3 wt.% of Al. The observed processes and the formation of corrosion products are recorded and differences in the behaviour of the two coatings are discussed

  13. Chemical reactions of fission product deposits and iodine transport in primary circuit conditions

    International Nuclear Information System (INIS)

    Highlights: • With CsI precursor, 20% of released iodine was in gaseous form in steam flow at 650 °C. • In similar conditions with Mo, gaseous iodine fraction was increased to 38–79%. • Boron trapped most of the caesium and iodine was almost completely released as gas. - Abstract: The objective of this work was to examine the chemical reactions taking place on primary circuit surfaces and their effect on fission product transport in a severe nuclear reactor accident. Especially transport of gaseous and aerosol phase iodine was studied. Caesium iodide (CsI) was used as precursor material for iodine species. Also, effects of molybdenum and boron on transport of iodine were investigated. The experimental work showed that when CsI alone was used as a precursor, as much as 20% of the released iodine was in gaseous form and the rest as aerosol particles. Aerosol particles were most likely CsI. When the amount of hydrogen in the carrier gas was increased, the fraction of gaseous iodine decreased. When Boron was added to the precursor, a glassy caesium borate surface was formed on the crucible. Boron trapped most of the caesium and also a fraction of iodine, causing almost all released iodine to be in gaseous form. When Mo was introduced in the precursor, most of the iodine was again released in gaseous form. Oxidised Mo reacted with caesium releasing iodine from CsI. The effect of Mo on iodine transport depended much on H2 concentration and was observed to be substantially greater on stainless steel surface. When stainless steel crucible was used, Mo was found in small amounts from aerosol particles, indicating that it was probably released as caesium molybdate or as molybdenum oxide

  14. Conditional Toxicity Value (CTV) Predictor for Generating Toxicity Values for Data Sparse Chemicals (Poster)

    Science.gov (United States)

    Various stakeholders and expert groups, including the National Research Council in Science and Decisions, call for “default approaches to support risk estimation for chemicals lacking chemical-specific information.” This project aims to address this challenge through ...

  15. Corrosion resistance of welded joints of OX18H10T and 20K steels under multiple chemical decontamination conditions

    Energy Technology Data Exchange (ETDEWEB)

    Olschewski, M. (VEB Dampfkesselbau Hohenthurm bei Halle (German Democratic Republic))

    1985-07-01

    Some results of studies on the corrosion behaviour of welded joints of materials typical for nuclear power plants under multiple chemical decontamination conditions are presented and interpreted. The studies were restricted to clean unirradiated samples. Objective of this work was to specify frequency criteria for decontaminating primary circuit equipment.

  16. Regulated expression of pH sensing G protein-coupled receptor-68 identified through chemical biology defines a new drug target for ischemic heart disease

    OpenAIRE

    Russell, Jamie L; Goetsch, Sean C.; Aguilar, Hector R.; Coe, Helen; Luo, Xiang; Liu, Ning; Van Rooij, Eva; Frantz, Doug E.; Schneider, Jay W.

    2012-01-01

    Chemical biology promises discovery of new and unexpected mechanistic pathways, protein functions and disease targets. Here, we probed the mechanism-of-action and protein targets of 3,5-disubstituted isoxazoles (Isx), cardiomyogenic small-molecules that target Notch-activated epicardium-derived cells (NECs) in vivo and promote functional recovery after myocardial infarction (MI). Mechanistic studies in NECs led to an Isx-activated Gq protein-coupled receptor (GqPCR) hypothesis tested in a cel...

  17. Li ceramic pebbles chemical compatibility with Eurofer samples in fusion relevant conditions

    International Nuclear Information System (INIS)

    Information on the chemical compatibility between Li ceramic breeders and reactor structural materials is an important issue for fusion reactor technology. In this work, Eurofer samples were placed inside a Li ceramic pebble bed and kept at 600 deg. C under a reducing atmosphere obtained by the flow of a purging gas (He + 0.1vol.%H2). Titanate and orthosilicate Li pebble beds were used in the experiments and exposure time ranged from 50 to 2000 h. Surface chemical reactions were investigated with nuclear microprobe techniques. The orthosilicate pebbles present chemical reactions even with the gas mixture, whereas for the samples in close contact with Eurofer there is evidence of Eurofer elemental diffusion into the pebbles and the formation of different types of compounds. Although the titanate pebbles used in the chemical compatibility experiments present surface alterations with increasing surface irregularities along the annealing time, there is no clear indication of Eurofer constituents diffusion

  18. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  19. Model experiments on simulation of the WWER water-chemical conditions at loop facilities of the MIR reactor

    International Nuclear Information System (INIS)

    The experiments on simulation of the WWER type reactors water-chemical conditions have been started at the State Scientific Center RIAR. These experiments are being conducted at the multi-loop research MIR reactor at the PVK-2 loop facility. The dosage stand was created. It allows introduction of boric acid, potassium and lithium hydroxides, ammonia solutions and gaseous hydrogen. Corrosion tests of the Russian E-635 and E-110 alloys are being conducted at the PVK-2 loop under the WWER water-chemical conditions. If necessary, fuel elements are periodically extracted from the reactor to perform visual examination, to measure their length, diameter, to remove the deposits from the claddings, to measure the burnup and to distribute the fission products over the fuel element by gamma-spectrometry. The chemical analytical 'on line' equipment produced by the ORBISPHERE Laboratory (Switzerland) will be commissioned in the nearest future to measure concentration of the dissolved hydrogen and oxygen as well as pH and specific conductivity. The objective of the report is to familiarize the participants of the IAEA Technical Committee with the capabilities of performing the model water-chemical experiments under the MIR reactor loop facility conditions. (author)

  20. Exact solutions for the magnetohydrodynamic flow of a Jeffrey fluid with convective boundary conditions and chemical reaction

    Energy Technology Data Exchange (ETDEWEB)

    Alsaedi, Ahmed [King Abdulaziz Univ., Jeddah (Saudi Arabia). Dept. of Mathematics; Iqbal, Zahid; Hayat, Tasawar [Quaid-i-Azam Univ., Islamabad (Pakistan). Dept. of Mathematics; Mustafa, Meraj [National Univ. of Sciences and Technology (NUST), Islamabad (Pakistan). Research Centre for Modeling and Simulation (RCMS)

    2012-08-15

    The two-dimensional magnetohydrodynamic (MHD) flow of a Jeffrey fluid is investigated in this paper. The characteristics of heat and mass transfer with chemical reaction have also been analyzed. Convective boundary conditions have been invoked for the thermal boundary layer problem. Exact similarity solutions for flow, temperature, and concentration are derived. Interpretation to the embedded parameters is assigned through graphical results for dimensionless velocity, temperature, concentration, skin friction coefficient, and surface heat and mass transfer. The results indicate an increase in the velocity and the boundary layer thickness by increasing the rheological parameter of the Jeffrey fluid. An intensification in the chemical reaction leads to a thinner concentration boundary layer. (orig.)

  1. Rapid Copper Metallization of Textile Materials: a Controlled Two-Step Route to Achieve User-Defined Patterns under Ambient Conditions.

    Science.gov (United States)

    Zhang, Shuang-Yuan; Guan, Guijian; Jiang, Shan; Guo, Hongchen; Xia, Jing; Regulacio, Michelle D; Wu, Mingda; Shah, Kwok Wei; Dong, Zhili; Zhang, Jie; Han, Ming-Yong

    2015-09-30

    Throughout history earth-abundant copper has been incorporated into textiles and it still caters to various needs in modern society. In this paper, we present a two-step copper metallization strategy to realize sequentially nondiffusive copper(II) patterning and rapid copper deposition on various textile materials, including cotton, polyester, nylon, and their mixtures. A new, cost-effective formulation is designed to minimize the copper pattern migration on textiles and to achieve user-defined copper patterns. The metallized copper is found to be very adhesive and stable against washing and oxidation. Furthermore, the copper-metallized textile exhibits excellent electrical conductivity that is ~3 times better than that of stainless steel and also inhibits the growth of bacteria effectively. This new copper metallization approach holds great promise as a commercially viable method to metallize an insulating textile, opening up research avenues for wearable electronics and functional garments. PMID:26361094

  2. Forest condition and chemical characteristics of atmospheric depositions: research and monitoring network in Lombardy

    OpenAIRE

    Flaminio DI GIROLAMO; Antonio TAGLIAFERRI; Gianni TARTARI; Balestrini, Raffaella

    2002-01-01

    Since 1987, the Regional Forestry Board of Lombardy and the Water Research Institute of the National Research Council have been carrying out surveys of forest conditions and the response of the ecosystem to environmental factors. The study approach is based on a large number of permanent plots for extensive monitoring (Level 1). At this level, crown condition is assessed annually, and soil condition and the nutritional status of forests surveyed. Some of the permanent plots were selected for ...

  3. Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study. Executive summary

    Science.gov (United States)

    Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

    1982-01-01

    Preferred techniques for providing abort pressurization and engine feed system net positive suction pressure (NPSP) for low thrust chemical propulsion systems (LTPS) were determined. A representative LTPS vehicle configuration is presented. Analysis tasks include: propellant heating analysis; pressurant requirements for abort propellant dump; and comparative analysis of pressurization techniques and thermal subcoolers.

  4. Physico-chemical stability of SiC/SiC fiber ceramic composites after exposure to fusion-relevant conditions

    International Nuclear Information System (INIS)

    The physico-chemical stability of SiC/SiC fiber ceramic composite (SiC/SiCf) in contact with Li2O in fusion-relevant conditions has been experimentally studied at 800 C in flowing helium (0.1 L/min) containing either 0.1% H2 or 100 ppm H2O and for exposure times of up to 4,032 h. The exposed SiC/SiC specimens have been characterized. The results obtained demonstrate that although the surface coating of the specimens is strongly attacked through chemical corrosion processes, the main physico-chemical characteristics of SiC/SiCf are affected to a limited extent only in the case of He + 0.1% H2 flowing gas, the bulk material not being attacked

  5. Modelling chemistry in aircraft plumes 2: the chemical conversion of NOx to reservoir species under different conditions

    International Nuclear Information System (INIS)

    An expanding plume model with chemistry has been used to study the chemical conversion of nitrogen oxides to reservoir species in aircraft plumes under various conditions. A plume from a B747 was studied, where the NOx emission index was 26.1 g kg-1. Several sensitivity tests were performed for emissions at 07 UT at 50oN under summer conditions. The amount of NOx remaining in the plume after 15 h was between 58 and 69%, assuming background concentrations of ozone and NOx ranging from 50 to 200 ppb and 50 to 200 ppt, respectively. A somewhat higher range in the chemical conversion of NOx was calculated when changing the temperature from 200 to 240 K. The remaining NOx in the plume increased to 90% in a study where the aircraft emissions were released in air masses already exposed to aircraft emissions some hours before. The rate of chemical conversion of NOx to reservoir species was highly dependent on the number of sunlit hours during the 15 h period. The diurnal, seasonal and latitudinal variations in the chemical conversion of NOx to reservoir species were studied. As a first approximation, the conversion rates can be used to modify the aircraft NOx emissions at cruise altitudes used in mesoscale models. (author)

  6. Color and chemical composition and of green corn produced under organic and conventional conditions

    Directory of Open Access Journals (Sweden)

    Lucineia de Pinho

    2011-06-01

    Full Text Available The present study aimed to evaluate the chemical properties of green corn, grown in both organic and conventional farming systems, using a completely randomized factorial design. Four corn varieties (AG 1051, BR 106, SWB 551 and VIVI of green corn kernels were evaluated for color, proximate composition, total calories, carotenoids and bioactive amines. The farming system affected some chemical and physical characteristics of green corn, but this effect was dependent upon variety. In general, organic green corn kernels were reddish (a* color component and had higher levels of β-carotene compared to the conventional ones, suggesting that these characteristics are related. Moreover, organic green corn had higher levels of total carbohydrates and total energy compared to conventional varieties. On the other hand, crude fiber levels were higher in conventional grains - an unexpected result that deserves further investigation. Finally, the levels of cadaverine and spermine bioactive amines were not affected either by the corn variety or by the farming system.

  7. Carbon nanofiber aerogels for emergent cleanup of oil spillage and chemical leakage under harsh conditions

    OpenAIRE

    Zhen-Yu Wu; Chao Li; Hai-Wei Liang; Yu-Ning Zhang; Xin Wang; Jia-Fu Chen; Shu-Hong Yu

    2014-01-01

    To address oil spillage and chemical leakage accidents, the development of efficient sorbent materials is of global importance for environment and water source protection. Here we report on a new type of carbon nanofiber (CNF) aerogels as efficient sorbents for oil uptake with high sorption capacity and excellent recyclability. Importantly, the oil uptake ability of the CNF aerogels can be maintained over a wide temperature range, from liquid nitrogen temperature up to ca. 400°C, making them ...

  8. Modelling atmospheric chemical transformations under South African conditions / Gerhardus Dirk Fourie

    OpenAIRE

    Fourie, Gerhardus Dirk

    2000-01-01

    South Africa is in the process of adapting to new social and economical structures. The government has made it clear that the creation of work and economic growth is of the utmost importance. This policy will put South Africa's limited resources under enormous pressure and will have an adverse impact on the environment. In order to facilitate sound decision making, all aspects of the environmental impacts must be investigated, e.g. the necessary knowledge on atmospheric chemical transformatio...

  9. Efficient catalyst-free chemical fixation of carbon dioxide into 2-oxazolidinones under supercritical condition

    Institute of Scientific and Technical Information of China (English)

    Jing Xiu Xu; Jin Wu Zhao; Zhen Bin Jia

    2011-01-01

    4-Methylene-1,3-oxazolidin-2-ones can be synthesized from propargylic alcohols, primary amines and carbon dioxide under supercritical condition in the absence of any additional catalyst and solvent. Various propargylic alcohols and primary amines were examined.

  10. Chemical conversion of cisplatin and carboplatin with histidine in a model protein crystallized under sodium iodide conditions

    International Nuclear Information System (INIS)

    Crystals of HEWL with cisplatin and HEWL with carboplatin grown in sodium iodide conditions both show a partial chemical transformation of cisplatin or carboplatin to a transiodoplatin (PtI2X2) form. The binding is only at the Nδ atom of His15. A further Pt species (PtI3X) is also seen, in both cases bound in a crevice between symmetry-related protein molecules. Cisplatin and carboplatin are platinum anticancer agents that are used to treat a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine in hen egg-white lysozyme (HEWL) showed a partial chemical conversion of carboplatin to cisplatin owing to the high sodium chloride concentration used in the crystallization conditions. Also, the co-crystallization of HEWL with carboplatin in sodium bromide conditions resulted in the partial conversion of carboplatin to the transbromoplatin form, with a portion of the cyclobutanedicarboxylate (CBDC) moiety still present. The results of the co-crystallization of HEWL with cisplatin or carboplatin in sodium iodide conditions are now reported in order to determine whether the cisplatin and carboplatin converted to the iodo form, and whether this took place in a similar way to the partial conversion of carboplatin to cisplatin in NaCl conditions or to transbromoplatin in NaBr conditions as seen previously. It is reported here that a partial chemical transformation has taken place to a transplatin form for both ligands. The NaI-grown crystals belonged to the monoclinic space group P21 with two molecules in the asymmetric unit. The chemically transformed cisplatin and carboplatin bind to both His15 residues, i.e. in each asymmetric unit. The binding is only at the Nδ atom of His15. A third platinum species is also seen in both conditions bound in a crevice between symmetry-related molecules. Here, the platinum is bound to three I atoms identified based on their anomalous difference electron densities and their refined occupancies, with

  11. Chemical conversion of cisplatin and carboplatin with histidine in a model protein crystallized under sodium iodide conditions

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M.; Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9PL (United Kingdom)

    2014-08-29

    Crystals of HEWL with cisplatin and HEWL with carboplatin grown in sodium iodide conditions both show a partial chemical transformation of cisplatin or carboplatin to a transiodoplatin (PtI{sub 2}X{sub 2}) form. The binding is only at the N{sup δ} atom of His15. A further Pt species (PtI{sub 3}X) is also seen, in both cases bound in a crevice between symmetry-related protein molecules. Cisplatin and carboplatin are platinum anticancer agents that are used to treat a variety of cancers. Previous X-ray crystallographic studies of carboplatin binding to histidine in hen egg-white lysozyme (HEWL) showed a partial chemical conversion of carboplatin to cisplatin owing to the high sodium chloride concentration used in the crystallization conditions. Also, the co-crystallization of HEWL with carboplatin in sodium bromide conditions resulted in the partial conversion of carboplatin to the transbromoplatin form, with a portion of the cyclobutanedicarboxylate (CBDC) moiety still present. The results of the co-crystallization of HEWL with cisplatin or carboplatin in sodium iodide conditions are now reported in order to determine whether the cisplatin and carboplatin converted to the iodo form, and whether this took place in a similar way to the partial conversion of carboplatin to cisplatin in NaCl conditions or to transbromoplatin in NaBr conditions as seen previously. It is reported here that a partial chemical transformation has taken place to a transplatin form for both ligands. The NaI-grown crystals belonged to the monoclinic space group P2{sub 1} with two molecules in the asymmetric unit. The chemically transformed cisplatin and carboplatin bind to both His15 residues, i.e. in each asymmetric unit. The binding is only at the N{sup δ} atom of His15. A third platinum species is also seen in both conditions bound in a crevice between symmetry-related molecules. Here, the platinum is bound to three I atoms identified based on their anomalous difference electron densities

  12. Flux Analysis of the Metabolism of Clostridium cellulolyticum Grown in Cellulose-Fed Continuous Culture on a Chemically Defined Medium under Ammonium-Limited Conditions

    OpenAIRE

    Desvaux, Mickaël; Petitdemange, Henri

    2001-01-01

    An investigation of cellulose degradation by the nonruminal, cellulolytic, mesophilic bacterium Clostridium cellulolyticum was performed in cellulose-fed chemostat cultures with ammonium as the growth-limiting nutrient. At any dilution rate (D), acetate was always the main product of the catabolism, with a yield of product from substrate ranging between 37.7 and 51.5 g per mol of hexose equivalent fermented and an acetate/ethanol ratio always higher than 1. As D rose, the acetyl coenzyme A wa...

  13. Advancement of the 10-species subgingival Zurich Biofilm model by examining different nutritional conditions and defining the structure of the in vitro biofilms

    Directory of Open Access Journals (Sweden)

    Ammann Thomas W

    2012-10-01

    Full Text Available Abstract Background Periodontitis is caused by a highly complex consortium of bacteria that establishes as biofilms in subgingival pockets. It is a disease that occurs worldwide and its consequences are a major health concern. Investigations in situ are not possible and the bacterial community varies greatly between patients and even within different loci. Due to the high complexity of the consortium and the availability of samples, a clear definition of the pathogenic bacteria and their mechanisms of pathogenicity are still not available. In the current study we addressed the need of a defined model system by advancing our previously described subgingival biofilm model towards a bacterial composition that reflects the one observed in diseased sites of patients and analysed the structure of these biofilms. Results We further developed the growth media by systematic variation of key components resulting in improved stability and the firm establishment of spirochetes in the 10-species subgingival Zurich biofilm model. A high concentration of heat-inactivated human serum allowed the best proliferation of the used species. Therefore we further investigated these biofilms by analysing their structure by confocal laser scanning microscopy following fluorescence in situ hybridisation. The species showed mutual interactions as expected from other studies. The abundances of all organisms present in this model were determined by microscopic counting following species-specific identification by both fluorescence in situ hybridisation and immunofluorescence. The newly integrated treponemes were the most abundant organisms. Conclusions The use of 50% of heat-inactivated human serum used in the improved growth medium resulted in significantly thicker and more stable biofilms, and the quantitative representation of the used species represents the in vivo community of periodontitis patients much closer than in biofilms grown in the two media with less or no

  14. Chemical conditions in present and future ecosystems in Forsmark - implications for selected radionuclides in the safety assessment SR-Site

    Energy Technology Data Exchange (ETDEWEB)

    Troejbom, Mats (Mats Troejbom Konsult AB (Sweden)); Grolander, Sara (Facilia AB (Sweden))

    2010-12-15

    This report is a background report for the biosphere analysis of the SR-Site Safety Assessment. This work aims to describe the future development of the chemical conditions at Forsmark, based on the present chemical conditions at landscape level taking landscape development and climate cases into consideration. The results presented contribute to the overall understanding of the present and future chemistry in the Forsmark area, and specifically, to the understanding of the behaviour of some selected radionuclides in the surface system. The future development of the chemistry at the site is qualitatively discussed with focus on the interglacial within the next 10,000 years. The effects on the chemical environment of future climate cases as Global Warming and cold permafrost climates are also briefly discussed. The work is presented in two independent parts describing background radionuclide activities in the Forsmark area and the distribution and behaviour of a large number of stable elements in the landscape. In a concluding section, implications of the future chemical environment of a selection of radionuclides important in the Safety Assessment are discussed based on the knowledge of stable elements. The broad range of elements studied show that there are general and expected patterns for the distribution and behaviour in the landscape of different groups of elements. Mass balances reveal major sources and sinks, pool estimations show where elements are accumulated in the landscape and estimations of time-scales give indications of the potential future development. This general knowledge is transferred to radionuclides not measured in order to estimate their behaviour and distribution in the landscape. It could be concluded that the future development of the chemical environment in the Forsmark area might affect element specific parameters used in de radionuclide model in different directions depending on element. The alternative climate cases, Global Warming

  15. Simulation of chemically reactive solute transport under conditions of changing temperature

    International Nuclear Information System (INIS)

    A numerical code, THCC, has been developed for simulation of multicomponent solute transport in saturated porous media with aqueous complexation and precipitation/dissolution of stable solid phases in the presence of variable temperature. THCC evolved from the isothermal code CHEMTRN and is capable of simulating the diffusion of solutes along a steady gradient of temperature and the mixing of fluids having different initial compositions and temperatures. Example calculations demonstrate the close coupling that can exist between temperature variations and the transport of chemically reactive solutes. This coupling can be an important consideration in the assessment of performance of nuclear waste repositories

  16. Disruption of biofilms from sewage pipes under physical and chemical conditioning

    Institute of Scientific and Technical Information of China (English)

    Charbel Mahfoud; Antoine El Samrani; Rita Mouawad; Walid Hleihel; Rim El Khatib; Bruno S. Lartiges; Naim Ouaini

    2009-01-01

    Biofilms grown inside two sewage collecting pipes located in industrial and residential areas are studied. Bacterial biomass inside three layers of biofilms was evaluated. Biofilm cohesion under different mixing rate and ionic strength was also investigated. Effects of physical and chemical parameters in the biofilms were evaluated by monitoring turbidity, chemical and biochemical oxygen demands. Extracted organic matter from biofilms was partitioned to polar, aromatic and saturated fractions using activated silica column chromatography. Results revealed that bacterial biomass growth depending on biofilm thickness and stratification. The most loaded stratum in bacterial biomass was the sewage-biofilm interface stratum that represented 51% of the total bacterial biomass. Stirring rate and ionic strength of mono and bivalent salts showed a major influence in biofilm disruption. The stirring time enhanced the exchange dynamic and matter capture between biofilm fragments at the critical stirring rate 90 r/min. Sodium chloride showed the dispersing effect on biofilms in suspension, and decreased the BOD5 (biochemical oxygen demand) beyond the physiological salt concentration.

  17. G-BASE data conditioning procedures for stream sediment and soil chemical analyses

    OpenAIRE

    T. R. Lister; Johnson, C C

    2005-01-01

    Data conditioning is the process of making data fit for the purpose for which it is to be used and forms a significant component of the G-BASE project. This report is part of a series of manuals to record G-BASE project methodology. For data conditioning this has been difficult as applications used for processing data and the way in which data are reported continue to evolve rapidly and sections of this report have had to be continually updated to reflect this fact. However, the principals of...

  18. Heavy metals content in reproductive organs of small mammals inhabiting in condition of chronic chemical exposure

    International Nuclear Information System (INIS)

    In this research by example of bank vole the heavy metals concentrations (cadmium, copper and zinc) in reproductive organs of small mammals inhabiting in condition of environmental pollution with wastes from copper-smelting industry have been considered. The levels of radionuclides accumulation in testes, seminal vesicle and ovaries of voles with radionuclide concentration in others organs and tissues of animals have been compared.

  19. The physical and chemical degradation of PWR fuel rods in severe accident conditions

    International Nuclear Information System (INIS)

    An experimental study of the interaction between Zircaloy-4 cladding and UO2 in PWR fuel rods heated to high temperatures with a negligible differential pressure across the cladding wall is described. The fuel rods were of dimensions appropriate to the 17x17 PWR fuel sub-assembly and were heated in a non-oxidising environment (vacuum) up to approx. 1850 deg. C either isothermally or through heating ramps. Observations were made concerning the extent and nature of the reaction zone between Zircaloy-4 and UO2 over the temperature range 1500-1850 deg. C for times ranging from 1 min to 125 min. The location, morphology and the chemical composition of the phases formed are described along with the kinetics of their formation. (author)

  20. A complementary metal oxide semiconductor—integrable conditioning circuit for resistive chemical sensor management

    International Nuclear Information System (INIS)

    This paper presents a new interface circuit (for MOX-based resistive chemical sensors) capable of overcoming the main limit of the circuits based on the resistance-to-time approach, i.e. the long measuring time with high-value resistances. The system is designed to operate with a single supply of 3.3 V, thus facilitating an ASIC implementation together with digital electronics for a first data analysis and transmission. This is particularly advantageous when the elaboration process requires a large computational load and a data pre-elaboration is advisable. Simulations of the integrable solution of the system have shown the feasibility of the proposed approach. A prototype with discrete components has been furthermore fabricated and experimentally tested, showing good performance in the range 0.5 MΩ to 10 GΩ with a maximum measuring time of 60 ms

  1. Evolution of limestone fracture permeability under coupled thermal, hydrologi-cal, mechanical, and chemical conditions

    Institute of Scientific and Technical Information of China (English)

    李凤滨; 盛金昌; 詹美礼; 徐力猛; 吴强; 贾春兰

    2014-01-01

    The effect of temperature on the rock fracture permeability is a very important factor in the prediction of the permeability of enhanced geothermal systems and in reservoir engineering. In this study, the flow-through experiments were conducted on a single limestone fracture at different temperatures of 25oC, 40oC and 60oC, and with differential pressures of 0.3 MPa and 0.4 MPa. The experimental results suggest a complex temporal evolution of the fracture aperture. The aperture increases considerably with increasing temperature and reduces gradually to a steady value at a stable temperature. The results of three short-term experiments (QT-1, QT-2, QT-3) indicate an exponential relationship between the permeability and the temperature change ratio (DT/T ) , which provides a further evidence that the rising temperature increases the aperture. It is shown that the changing temperature has its influence on two possible accounts:the chemical dissolution and the pressure dissolution. These two processes have opposite impacts on the fracture permeability. The chemical dissolution increases the permeability with a rising temperature while the pressure disso-lution reduces the permeability with a stable temperature. These make a very complex picture of the permeability evolution. Our results show that the fracture permeability reduces 39.2%when the temperature increases by 15oC (during the 25oC-40 C interval) and 42.6% when the temperature increases by 20oC (during the 40oC-60oC interval). It can be concluded that the permeability decreases to a greater extent for larger increases in temperature.

  2. Meteorites and the physico-chemical conditions in the early solar nebula

    CERN Document Server

    Aleon, Jerome

    2008-01-01

    Chondritic meteorites constitute the most ancient rock record available in the laboratory to study the formation of the solar system and its planets. Detailed investigations of their mineralogy, petrography, chemistry and isotopic composition and comparison with other primitive solar system samples such as cometary dust particles have allowed through the years to decipher the conditions of formation of their individual components thought to have once been free-floating pieces of dust and rocks in the early solar nebula. When put in the context of astrophysical models of young stellar objects, chondritic meteorites and cometary dust bring essential insights on the astrophysical conditions prevailing in the very first stages of the solar system. Several exemples are shown in this chapter, which include (1) high temperature processes and the formation of chondrules and refractory inclusions, (2) oxygen isotopes and their bearing on photochemistry and large scale geochemical reservoirs in the nebula, (3) organosy...

  3. Evaluation of the migration of chemicals from baby bottles under standardised and duration testing conditions.

    Science.gov (United States)

    Onghena, Matthias; Van Hoeck, Els; Negreira, Noelia; Quirynen, Laurent; Van Loco, Joris; Covaci, Adrian

    2016-05-01

    After the prohibition of bisphenol-A-containing polycarbonate baby bottles in the European Union (EU), alternative materials, such as polypropylene, polyethersulphone, Tritan™ copolyester, etc., have appeared on the market. Based on an initial screening and in vitro toxicity assessment, the most toxic migrating compounds were selected to be monitored and quantified using validated GC- and LC-QqQ-MS methods. The effect of several 'real-life-use conditions', such as microwave, sterilisation and dishwasher, on the migration of different contaminants was evaluated by means of duration tests. These results were compared with a reference treatment (filling five times with pre-heated simulant at 40°C) and with the legal EU 'repetitive-use conditions' (three migrations, 2 h at 70°C). Analysis of the third migration step of the EU repetitive-use conditions (which has to comply with the EU legislative migration limits) showed that several non-authorised compounds were observed in some baby bottles exceeding 10 µg kg(-1). However, all authorised compounds were detected well below their respective specific migration limits (SMLs). The reference experiment confirmed the migration of some of the compounds previously detected in the EU repetitive-use experiment, though at lower concentrations. Analysis of extracts from the microwave and dishwasher experiments showed a reduction in the migration during the duration tests. In general, the concentrations found were low and comparable with the reference experiment. Similar observations were made for the two sterilisation types: steam and cooking sterilisation. However, steam sterilisation seems to be more recommended for daily use of baby bottles, since it resulted in a lower release of substances afterwards. Repeated use of baby bottles under 'real-life' conditions showed no increase in the migration of investigated compounds and, after some time, the migration of these compounds even became negligible. PMID:27043734

  4. Degradation Kinetics of Atorvastatin under Stress Conditions and Chemical Analysis by HPLC

    Directory of Open Access Journals (Sweden)

    Romanélia Spessemille Valotto

    2013-01-01

    Full Text Available Atorvastatin is an antilipemic drug belonging to the statins class, whose reference drug is Pfizer’s Lipitor®. It is used to reduce the levels of lipoproteins rich in cholesterol and reduce the risk of coronary artery disease. It is well-known that calcium atorvastatin (ATV, C66H68CaF2N4O10•3H2O, presents polymorphism. The drug in question is commonly sought after by pharmaceutical industries that produce generic drugs, due to the fact that the drug has a high value price, it is consumed globally, and its patent expired in late 2010. Many questions concerning this drug’s pharmaceutical scope demonstrate its importance regarding stability studies and the identification of degradation products of drugs and pharmaceutical formulations. ATV has been found to degrade under acid and basic conditions, including a first order kinetic degradation under acid conditions, as compared to a zero order kinetic degradation under basic conditions, which tends to be less stable when studied within acid mediums. The rate constant (k for degradation in acid medium was 1.88 × 10−2 s−1 (first order, while for basic medium k = 2.35 × 10−4 mol L−1 s−1 (zero order, demonstrating a lower stability of the drug within acid mediums.

  5. Antioxidant Status of Plants in Conditions of Chemical Pollution of the Urban Environment

    Directory of Open Access Journals (Sweden)

    L. V. MOSINA

    2014-06-01

    Full Text Available Antioxidants are substances that slow down the oxidation of organic compounds that protect the body from the negative effects of free radicals antioxidant connected with free radical and puts up a barrier to the corrosive effects of the electron. Enzyme protective system of the body converts cell oxidant into the water and oxygen.The body has its own system of struggle with excessive amounts of free radicals, but it has weakened under the impact of the polluted environment, direct sunlight and needs support. Scientists found that many plants contain substances flavonoids - a large group of polyphenolic compounds structure, which bind free radicals.This article presents a review of research performed in the Russian state endowment of the University of Immanuel Kant, the influence of chemical contaminated areas in the antioxidant status of the plants.Thus the study of the influence of factors on the formation of antioxidants plants is a fragment of a large-scale work on the study of natural antioxidants, which not only protect living organisms but also determine the quality of plant foods, feeds, and ultimately the quality of life and its duration. The solution of the problems of modern society - environmental, health, demography is impossible without change of attitude to food.

  6. Physical and chemical conditions in methanol maser selected hot-cores and UCHII regions

    CERN Document Server

    Purcell, C R; Burton, M G; Walsh, A J; Minier, V; Cunningham, M R; Balasubramanyam, R

    2008-01-01

    We present the results of a targeted 3-mm spectral line survey towards the eighty-three 6.67 GHz methanol maser selected star forming clumps observed by Purcell et al. 2006. In addition to the previously reported measurements of HCO+ (1 - 0), H13CO+ (1 - 0), and CH3CN (5 - 4) & (6 -5), we used the Mopra antenna to detect emission lines of N2H+ (1 - 0), HCN (1 - 0) and HNC (1 - 0) towards 82/83 clumps (99 per cent), and CH3OH (2 - 1) towards 78/83 clumps (94 per cent). The molecular line data have been used to derive virial and LTE masses, rotational temperatures and chemical abundances in the clumps, and these properties have been compared between sub-samples associated with different indicators of evolution. The greatest differences are found between clumps associated with 8.6 GHz radio emission, indicating the presence of an Ultra-Compact HII region, and `isolated' masers (without associated radio emission), and between clumps exhibiting CH3CN emission and those without. In particular, thermal CH3OH is ...

  7. Experimental setup for rapid crystallization using favoured chemical potential and hydrodynamic conditions

    OpenAIRE

    Dixit, VK; Rodrigues, BV; Bhat, HL

    2001-01-01

    The rapid crystallization of KH$_{2}$PO$_{4}$(KDP) from solution is demonstrated at a rate up to approximate to 7.5 mm/day along [100] and 22 mm/day along [001] in a crystallizer of 51 capacity, using accelerated crucible rotation technique (ACRT) and simulated platform geometry for controlling the hydrodynamic conditions. On an experimental basis we have grown the crystals up to 40 x 43 x 66 mm$^3$ size in about 3 days. Comparative analysis of the main structural and optical properties of cr...

  8. Situation with physical and chemical pollutants and climatic conditions in TPP 'Bitola' (Macedonia)

    International Nuclear Information System (INIS)

    The pollution with solid gaseous substances in work surroundings of the mine 'Suvodol' - Bitola in Bitola has been investigated. The presence of solid substances (mineral (coal) dust) exceeds maximum permitted concentration (MDK) in some of the work surroundings. It is consolidate that the solid substances (mineral (coal) dust) have component part of 9% SiO2. The concentration of CO, CO2, benzene, ksilol and phenol is smaller than maximum permitted one (MDK). The micro clime conditions, which are presented in investigated work surroundings, support pollution. (Author)

  9. Forest condition and chemical characteristics of atmospheric depositions: research and monitoring network in Lombardy

    Directory of Open Access Journals (Sweden)

    Flaminio DI GIROLAMO

    2002-09-01

    Full Text Available Since 1987, the Regional Forestry Board of Lombardy and the Water Research Institute of the National Research Council have been carrying out surveys of forest conditions and the response of the ecosystem to environmental factors. The study approach is based on a large number of permanent plots for extensive monitoring (Level 1. At this level, crown condition is assessed annually, and soil condition and the nutritional status of forests surveyed. Some of the permanent plots were selected for intensive monitoring (Level 2, focussing mainly on the impact of atmospheric pollution on forest ecosystems. Level 2 monitoring also includes increment analyses, ground vegetation assessment, atmospheric deposition, soil solution analyses and climatic observations. This paper summarises the main results of a pluriannual research, which provides a general picture of the state of forest health in the region and focuses on more detailed investigations, described as case studies. Modified wet and dry samplers which use a water surface to collect dry deposition were used in a pluriannual field campaign at five sites in alpine and prealpine areas, to measure the total atmospheric depositions and to evaluate the nitrogen and sulphate exceedances of critical loads. Throughfall and bulk precipitation chemistry were studied for five years (June 1994-May 1999 at two high elevation forest sites (Val Gerola and Val Masino which were known to differ in terms of tree health, as assessed by live crown condition. Results indicated a higher contribution from the dry deposition of N-NO3 -, N-NH4 + and H+ and considerable canopy leaching of Ca2+, K+ and weak organic acids at Val Gerola, where the symptoms of damage were more evident. In the area of Val Masino (SO, included since 1997 in the national CONECOFOR network, investigations focused on the effectiveness of the biological compartment in modifying fluxes of atmospheric elements, and on the role of nitrogen both as an

  10. Experimental setup for rapid crystallization using favoured chemical potential and hydrodynamic conditions

    Indian Academy of Sciences (India)

    V K Dixit; B V Rodrigues; H L Bhat

    2001-10-01

    The rapid crystallization of KH2PO4 (KDP) from solution is demonstrated at a rate up to ≈7.5 mm/day along [100] and 22 mm/day along [001] in a crystallizer of 5 l capacity, using accelerated crucible rotation technique (ACRT) and simulated platform geometry for controlling the hydrodynamic conditions. On an experimental basis we have grown the crystals up to 40 × 43 × 66 mm3 size in about 3 days. Comparative analysis of the main structural and optical properties of crystals grown by conventional and rapid crystallization technique, is discussed.

  11. Monitoring and physical-chemical modeling of conditions of natural surface and underground waters forming in the Kola North.

    Science.gov (United States)

    Mazukhina, Svetlana I; Masloboev, Vladimir A; Chudnenko, Konstantin V; Bychinsky, Valeriy A; Svetlov, Anton V; Muraviev, Sergey V

    2012-01-01

    Processes of surface and underground water forming in the Khibiny massif have been studied using a physical-chemical model of the "water-rock-atmosphere-organic substance" system. The obtained model solutions are indicative of the fact that formation of surface and underground water of the Khibiny massif takes place on the whole in the framework of the considered system without attracting a hypothetical outside source of pollutants. The results are of practical and methodological importance for assessment of prediction of the man-induced impact on water systems in conditions of Subarctic. PMID:22416860

  12. Effect of Dehydration Conditions on the Chemical, Physical, and Rehydration Properties of Instant Whole Bean (Phaseolus vulgaris L. var. Azufrado

    Directory of Open Access Journals (Sweden)

    Juan Alberto Resendiz Vazquez

    2015-01-01

    Full Text Available The purpose of this study was to evaluate the effect of dehydration conditions on the chemical, physical, and rehydration properties of instant whole beans (Phaseolus vulgaris L. var. Azufrado using a 22 factorial design (air temperature: 25°C and 30°C, air velocity: 0.5 m/s and 1.0 m/s. To determine the kinetic parameters, the rehydration data were fitted to three models: Peleg’s, First Order, and Sigmoid. The protein, fat, and ash contents of the beans were not significantly affected (P>0.05 by the dehydration conditions. Of the 11 physical properties of the instant whole beans, only water activity and splitting were significantly affected by dehydration conditions (P0.05 between the observed and predicted equilibrium moisture contents of the instant whole beans. Regarding the rehydration kinetics for the instant whole beans, the activation energy values ranged from 23.56 kJ/mol to 30.48 kJ/mol, depending on the dehydration conditions. The dehydration conditions had no significant effect (P>0.05 on the rehydration properties of instant whole beans.

  13. Description of the equilibrium conditions of chemical reactions in various solvents

    International Nuclear Information System (INIS)

    Empirical knowledge is taken as the basis for establishing a method to predict the equilibrium conditions of reactions of macrocyclic polyethers and monovalent metal cations in various solvents. The reactions in the solvents under review can be well described by the donor number DN according to Gutmann, and by the parameters alpha and pi-asterisk for the H bonding donor and polarity/polarisability, respectively, using a three-parameter equation according to Kamlet/Taft. This applies to both protic and aprotic solvents. The calculations rely on data found in the literature and on own experimental results obtained by microcalorimetric examinations. The evaluation methods evolved for this purpose also allow, by means of additional dilution experiments, to convert the ''integral'', microcalorimetrically obtained complex stability constants, (i.e. those non-discriminating between different types of state such as ions or ion pairs) to the corresponding ''differentiating'' constants (referring to purely ionic quantities), and this applied to the various solvents used. The method does not use foreign ions and can thus also be applied to those cases for which the normal standardisation of reaction conditions published in the literature cannot be maintained (e.g. for reasons of solubility). In some cases it was possible to obtain additional information on the dissociation behaviour of the salts used, which revealed differently strong inclination to form higher aggregations in solution, as shown e.g. by the strong concentration dependence of the salt ion pair dissociation constants obtained. (orig./EF)

  14. Exopolysaccharides from yeast: insight into optimal conditions for biosynthesis, chemical composition and functional properties – review

    Directory of Open Access Journals (Sweden)

    Iwona Gientka

    2015-12-01

    Full Text Available The yeast exopolysaccharides (EPS are not a well-established group of metabolites. An industrial scale    of this EPS production is limited mainly by low yield biosynthesis. Until now, enzymes and biosynthesis pathways, as well as the role of regulatory genes, have not been described. Some of yeast EPS show anti- tumor, immunostimulatory and antioxidant activity. Others, absorb heavy metals and can function as bioac- tive components of food. Also, the potential of yeast EPS as thickeners or stabilizers can be found. Optimal conditions for the biosynthesis of yeast exopolysaccharides require strong oxygenation and low temperature of the culture, due to the physiology of the producer strains. The medium should contain sucrose as a carbon source and ammonium sulfate as inorganic nitrogen source, wherein the C:N ratio in the substrate should be 15:1. The cultures are long and the largest accumulation of polymers is observed after 4 or 5 days of culturing. The structure of yeast EPS is complex which affects the strain and culture condition. The EPS from yeast are linear mannans, pullulan, glucooligosaccharides, galactooligosaccharides and other heteropolysaccharides containing α-1,2; α-1,3; α-1,6; β-1,3; β-1,4 bonds. Mannose and glucose have the largest participation of carbohydrates forming EPS.

  15. Low-thrust chemical propulsion system propellant expulsion and thermal conditioning study

    Science.gov (United States)

    Merino, F.; Wakabayashi, I.; Pleasant, R. L.; Hill, M.

    1982-01-01

    Thermal conditioning systems for satisfying engine net positive suction pressure (NPSP) requirements, and propellant expulsion systems for achieving propellant dump during a return-to-launch site (RTLS) abort were studied for LH2/LO2 and LCH4/LO2 upper stage propellant combinations. A state-of-the-art thermal conditioning system employing helium injection beneath the liquid surface shows the lowest weight penalty for LO2 and LCH4. A technology system incorporating a thermal subcooler (heat exchanger) for engine NPSP results in the lowest weight penalty for the LH2 tank. A preliminary design of two state-of-the-art and two new technology systems indicates a weight penalty difference too small to warrant development of a LH2 thermal subcooler. Analysis results showed that the LH2/LO2 propellant expulsion system is optimized for maximum dump line diameters, whereas the LCH4/LO2 system is optimized for minimum dump line diameter (LCH4) and maximum dump line diameter (LO2). The primary uncertainty is the accurate determination of two-phase flow rates through the dump system; experimentation is not recommended because this uncertainty is not considered significant.

  16. Studies of the behaviour of technical chemicals introduced into the subsoil under modelled conditions

    International Nuclear Information System (INIS)

    Because of the environmental hazard of organic solvents such as chlorinated or aromatic hydrocarbons, water soluble and biodegradable substitutes have come into use. It should be assessed how they affect soil and aquifer when spilled in leaks or accidents. This was simulated in a model system using methanol and percolation columns, one filled with material from the unsaturated subsurface and two with different materials from aquifers. The results reveal that a spill of the substitutes can also cause problems. In homogeneous soils and at long retention times until the substance reaches the aquifer, sorption and biological degradation are most likely to prevent contamination of the groundwater. When oxygen supply in the subsurface is insufficient, reducing conditions occur and sulphide is formed. The data show that much more methanol was eliminated than reflected by the consumption of electron acceptors. This indicates that sorption and anabolic turnover of the microorganisms play an important role in the elimination process. Additionally, the permeability of the soil decreases because of clogging by the biomass. This leads to reduced mobility of the pollutant. When acidic degradation products are formed, calcium and magnesium are mobilized and cause a hardening of the ground water. If the contamination reaches the ground water oxygen and nitrate will be consumed, causing reducing conditions. Where this is not acceptable, hydraulic remediation should be sufficient as a countermeasure. (orig.)

  17. Chemical profiling of Jatropha tissues under different torrefaction conditions: application to biomass waste recovery.

    Science.gov (United States)

    Watanabe, Taiji; Shino, Amiu; Akashi, Kinya; Kikuchi, Jun

    2014-01-01

    Gradual depletion of the world petroleum reserves and the impact of environmental pollution highlight the importance of developing alternative energy resources such as plant biomass. To address these issues, intensive research has focused on the plant Jatropha curcas, which serves as a rich source of biodiesel because of its high seed oil content. However, producing biodiesel from Jatropha generates large amounts of biomass waste that are difficult to use. Therefore, the objective of our research was to analyze the effects of different conditions of torrefaction on Jatropha biomass. Six different types of Jatropha tissues (seed coat, kernel, stem, xylem, bark, and leaf) were torrefied at four different temperature conditions (200°C, 250°C, 300°C, and 350°C), and changes in the metabolite composition of the torrefied products were determined by Fourier transform-infrared spectroscopy and nuclear magnetic resonance analyses. Cellulose was gradually converted to oligosaccharides in the temperature range of 200°C-300°C and completely degraded at 350°C. Hemicellulose residues showed different degradation patterns depending on the tissue, whereas glucuronoxylan efficiently decomposed between 300°C and 350°C. Heat-induced depolymerization of starch to maltodextrin started between 200°C and 250°C, and oligomer sugar structure degradation occurred at higher temperatures. Lignin degraded at each temperature, e.g., syringyl (S) degraded at lower temperatures than guaiacyl (G). Finally, the toxic compound phorbol ester degraded gradually starting at 235°C and efficiently just below 300°C. These results suggest that torrefaction is a feasible treatment for further processing of residual biomass to biorefinery stock or fertilizer. PMID:25191879

  18. Chemical profiling of Jatropha tissues under different torrefaction conditions: application to biomass waste recovery.

    Directory of Open Access Journals (Sweden)

    Taiji Watanabe

    Full Text Available Gradual depletion of the world petroleum reserves and the impact of environmental pollution highlight the importance of developing alternative energy resources such as plant biomass. To address these issues, intensive research has focused on the plant Jatropha curcas, which serves as a rich source of biodiesel because of its high seed oil content. However, producing biodiesel from Jatropha generates large amounts of biomass waste that are difficult to use. Therefore, the objective of our research was to analyze the effects of different conditions of torrefaction on Jatropha biomass. Six different types of Jatropha tissues (seed coat, kernel, stem, xylem, bark, and leaf were torrefied at four different temperature conditions (200°C, 250°C, 300°C, and 350°C, and changes in the metabolite composition of the torrefied products were determined by Fourier transform-infrared spectroscopy and nuclear magnetic resonance analyses. Cellulose was gradually converted to oligosaccharides in the temperature range of 200°C-300°C and completely degraded at 350°C. Hemicellulose residues showed different degradation patterns depending on the tissue, whereas glucuronoxylan efficiently decomposed between 300°C and 350°C. Heat-induced depolymerization of starch to maltodextrin started between 200°C and 250°C, and oligomer sugar structure degradation occurred at higher temperatures. Lignin degraded at each temperature, e.g., syringyl (S degraded at lower temperatures than guaiacyl (G. Finally, the toxic compound phorbol ester degraded gradually starting at 235°C and efficiently just below 300°C. These results suggest that torrefaction is a feasible treatment for further processing of residual biomass to biorefinery stock or fertilizer.

  19. Synthesis of SF5CF2-Containing Enones and Instability of This Group in Specific Chemical Environments and Reaction Conditions.

    Science.gov (United States)

    Dudziński, Piotr; Matsnev, Andrej V; Thrasher, Joseph S; Haufe, Günter

    2016-06-01

    The chemistry of the SF5CF2 moiety has been scarcely investigated. In this report, we present synthetic pathways to a variety of SF5CF2-substituted compounds starting from vinyl ethers and SF5CF2C(O)Cl. In specific chemical environments and under particular reaction conditions, the SF5CF2 moiety is unstable in downstream products resulting in the elimination of the SF5(-) anion and its decomposition to SF4 and F(-). Surprisingly, the formed F(-) can attack the intermediate difluorovinyl moiety to form trifluoromethyl substituted products. This appears to happen when an intermediate neighboring group participation involving a double bond is possible. Under slightly different conditions, the reaction stops at the stage of a difluorovinyl compound. PMID:27159371

  20. Effect of pH and chemical mechanical planarization process conditions on the copper–benzotriazole complex formation

    Science.gov (United States)

    Cho, Byoung-Jun; Kim, Jin-Yong; Hamada, Satomi; Shima, Shohei; Park, Jin-Goo

    2016-06-01

    Benzotriazole (BTA) has been used to protect copper (Cu) from corrosion during Cu chemical mechanical planarization (CMP) processes. However, an undesirable Cu–BTA complex is deposited after Cu CMP processes and it should be completely removed at post-Cu CMP cleaning for next fabrication process. Therefore, it is very important to understand of Cu–BTA complex formation behavior for its applications such as Cu CMP and post-Cu CMP cleaning. The present study investigated the effect of pH and polisher conditions on the formation of Cu–BTA complex layers using electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy) and the surface contact angle. The wettability was not a significant factor for the polishing interface, as no difference in the contact angles was observed for these processes. Both electrochemical techniques revealed that BTA had a unique advantage of long-term protection for Cu corrosion in an acidic condition (pH 3).

  1. Defining the vital condition for organ donation

    Directory of Open Access Journals (Sweden)

    Zamperetti Nereo

    2007-11-01

    Full Text Available Abstract The issue of organ donation and of how the donor pool can or should be increased is one with significant practical, ethical and logistic implications. Here we comment on an article advocating a paradigm change in the so-called "dead donor rule". Such change would involve the societal and legal abandonment of the above rule and the introduction of mandated choice. In this commentary, we review some of the problems associated with the proposed changes as well as the problems associated with the current model. We emphasize the continuing problems with the definition of death and the physiological process of dying; we discuss the difficulties associated with a dichotomous view of death; we review the difficulties with non-beating heart donation and emphasize the current limitations of society's understanding of these complex issues. We conclude that public education remains the best approach and that such education should not be merely promotion of a particular ideology but honest debate of what is socially and morally acceptable and appropriate given the changes in vital organ support technology and the need to respect patient autonomy.

  2. Electronic and chemical structure of the H2O/GaN(0001) interface under ambient conditions

    Science.gov (United States)

    Zhang, Xueqiang; Ptasinska, Sylwia

    2016-04-01

    We employed ambient pressure X-ray photoelectron spectroscopy to investigate the electronic and chemical properties of the H2O/GaN(0001) interface under elevated pressures and/or temperatures. A pristine GaN(0001) surface exhibited upward band bending, which was partially flattened when exposed to H2O at room temperature. However, the GaN surface work function was slightly reduced due to the adsorption of molecular H2O and its dissociation products. At elevated temperatures, a negative charge generated on the surface by a vigorous H2O/GaN interfacial chemistry induced an increase in both the surface work function and upward band bending. We tracked the dissociative adsorption of H2O onto the GaN(0001) surface by recording the core-level photoemission spectra and obtained the electronic and chemical properties at the H2O/GaN interface under operando conditions. Our results suggest a strong correlation between the electronic and chemical properties of the material surface, and we expect that their evolutions lead to significantly different properties at the electrolyte/electrode interface in a photoelectrochemical solar cell.

  3. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike, E-mail: angermann@helmholtz-berlin.de

    2014-09-01

    Highlights: • Determination of electronic interface properties by contact-less surface photovoltage (SPV) technique. • Systematic correlations of substrate morphology and surface electronic properties. • Optimization of surface pre-treatment for flat, saw damage etched, and textured Si solar cell substrates. • Ultra-thin passivating Si oxide layers with low densities of rechargeable states by wet-chemical oxidation and subsequent annealing. • Environmentally acceptable processes, utilizing hot water, diluted HCl, or ozone low cost alternative to current approaches with concentrated chemicals. • The effect of optimized wet-chemical pre-treatments can be preserved during subsequent layer deposition. - Abstract: The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution D{sub it}(E), and density D{sub it,min} of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly

  4. Control of transport and magnetism in ferromagnetic semiconducting superlattices through growth conditions and chemical surface effects

    Science.gov (United States)

    Kreutz, Theodore Carlton

    2003-10-01

    addition of chemical adsorbates. We find that we can reduce the Curie temperature by over 50 K. The reduction is linked to how well ordered the adsorbate is.

  5. Chemical environment for strainers at loss of coolant conditions in a PWR

    International Nuclear Information System (INIS)

    The present report describes the chemical environment in the neighbourhood of the strainer as a function of time after a large to medium-sized LOCA has started in a PWR. It also outlines some of the possible consequences for strainer filtration throughout the LOCA process. The most important factor for strainer behaviour is the presence of material that could be filtered onto the strainer. Examples of materials which could cause problems at strainer filtration are insulation fibers, concrete, corrosion products, paints, organic materials etc. A felt of fibrous material will probably form rapidly due to mechanical filtration on the strainers after start of recirculation. The chemistry of the strainer environment is characterized by relatively high concentrations of boric acid, lithium hydroxide and phosphate in the short time frame. Dissolved concrete and pyrolytic, acidic products could be important after 24 h. pH will be high from the very beginning of the LOCA and thereafter increase due to dissolution of Na3PO4 12H2O placed in baskets in the containment. Mechanically induced filtration would probably be the main cause of differential pressure build-up over the strainer felt as long as pH is high enough in the sump water. pH would remain high as long as large amounts of pyrolytic products are not formed. A high pH is essential to prevent fines and small particles to coagulate and deposit which will subsequently cause differential pressure build-up over the strainers. During the first time period of strainer filtration differential pressure build-up due to mechanically induced felt growth will occur. There could also be some contribution from positively charged or almost neutral fines and particles of mineral wool, Caposil, Minileit, and organic material if present. However, this is not foreseen as a major problem as positively charged particles should be in minority. If pyrolytic production of large amounts of acidic material starts, pH could drop dramatically

  6. Sensitivity of the invasive bivalve Corbicula fluminea to candidate control chemicals: The role of dissolved oxygen conditions.

    Science.gov (United States)

    Rosa, Inês C; Garrido, Rita; Ré, Ana; Gomes, João; Pereira, Joana L; Gonçalves, Fernando; Costa, Raquel

    2015-12-01

    The freshwater Corbicula fluminea is a major aquatic nuisance worldwide. Current pest control methods raise cost-effectiveness and environmental concerns, which motivate research into improved mitigation approaches. In this context, the susceptibility of the clams to chemicals under reduced oxygen conditions was examined. Biocides with different mechanisms of toxicity (niclosamide, polyDADMAC, ammonium nitrate, potassium chloride and dimethoate) were tested under normoxic (>7 mg L(-1) dissolved O2) and hypoxic (ammonium nitrate and dimethoate, clam mortality enhancements up to 400% were observed under hypoxia as compared to dosing upon normal dissolved oxygen conditions. For polyDADMAC and potassium chloride, substantially lower mortality enhancements were found. The differences in the clams' sensitivity to the chemicals under hypoxia could be linked to the expected mechanisms of action. This suggests that judicious selection of the biocide is essential if optimized combined control treatments are to be designed and provides an insight into the interference of frequent hypoxia events in the response of natural clam populations to contaminant loads. PMID:26254082

  7. Physical properties, chemical composition, and cloud forming potential of particulate emissions from a marine diesel engine at various load conditions.

    Science.gov (United States)

    Petzold, A; Weingartner, E; Hasselbach, J; Lauer, P; Kurok, C; Fleischer, F

    2010-05-15

    Particulate matter (PM) emissions from one serial 4-stroke medium-speed marine diesel engine were measured for load conditions from 10% to 110% in test rig studies using heavy fuel oil (HFO). Testing the engine across its entire load range permitted the scaling of exhaust PM properties with load. Emission factors for particle number, particle mass, and chemical compounds were determined. The potential of particles to form cloud droplets (cloud condensation nuclei, CCN) was calculated from chemical composition and particle size. Number emission factors are (3.43 +/- 1.26) x 10(16) (kg fuel)(-1) at 85-110% load and (1.06 +/- 0.10) x 10(16) (kg fuel)(-1) at 10% load. CCN emission factors of 1-6 x 10(14) (kg fuel)(-1) are at the lower bound of data reported in the literature. From combined thermal and optical methods, black carbon (BC) emission factors of 40-60 mg/(kg fuel) were determined for 85-100% load and 370 mg/(kg fuel) for 10% load. The engine load dependence of the conversion efficiency for fuel sulfur into sulfate of (1.08 +/- 0.15)% at engine idle to (3.85 +/- 0.41)% at cruise may serve as input to global emission calculations for various load conditions. PMID:20402501

  8. THE EFFECT OF CHARGE AND CHEMICAL STRUCTURE OF CATIONIC SURFACTANTS ON LASER TONER AGGLOMERATION UNDER ALKALINE PULPING CONDITIONS

    Directory of Open Access Journals (Sweden)

    Jie Jiang,

    2012-02-01

    Full Text Available Laboratory-scale agglomeration experiments followed by image analysis were used to evaluate the effectiveness of different cationic surfactants on the 1-octadecanol agglomeration of a negatively charged laser toner. Various types of surfactants with different geometric structures were investigated. It was found that this toner became agglomerated under neutral pulping conditions, but it did not agglomerate under alkaline conditions at all. A small amount of the cationic surfactant compensated for the agglomeration disruption caused by the negative surface charge of the toner and made this toner agglomerate very well. These cationic surfactants consist of a chemical structure of C12 to C18 saturated alkyl hydrophobic chains. The positive charge of these surfactants played the major role in alleviating agglomeration disruption. Additionally, an extra phenol group on these surfactants contributed only minor advantages for toner agglomeration in the presence of 1-octadecanol. The best co-agglomeration performance occurred within a very narrow range of similar total positive charge densities based on the total toner weight. It was also found that this positive charge effect could not be applied to the chemical compounds of high molecular weight polymeric materials.

  9. Chemical reduction and sulfur-isotope effects of sulfate by organic matter under hydrothermal conditions

    International Nuclear Information System (INIS)

    Under hydrothermal conditions sulfuric acid, sodium bisulfate and sodium sulfate solutions were reduced by dextrose to hydrogen sulfide in order to clarify the origin of sulfide species in hot-springs, geothermal water and ore-forming fluids. At temperatures above 2500C, reduction of sulfuric acid and at above 3000C of sodium bisulfate and sodium sulfate was observed. The reduction rate depends fairly well on the temperatures, pH and sulfate species. The reduction of sulfate seems to be a first-order reaction. Sulfur-isotope compositions of sulfate and hydrogen sulfide were measured in order to disclose isotope effects in the reduction of sulfate. The reduction of sulfuric acid and sodium bisulfate solution results in enrichment of 32S in the hydrogen sulfide and of the heavy isotope into residual sulfate. The fractionation factor in the reduction is independent of the temperature and is seen to be 1.007 to 1.009, in agreement with previously published values. (Auth.)

  10. Photoacoustic physio-chemical analysis of liver conditions in animal and human subjects

    Science.gov (United States)

    Wang, Xueding; Xu, Guan; Tian, Chao; Wan, Shanshan; Welling, Theodore H.; Lok, Anna S. F.; Rubin, Jonathan M.

    2016-03-01

    Non-alcoholic fatty liver disease (NAFLD) is a common liver disease affecting 30% of the population in the United States. Biopsy is the gold standard for diagnosing NAFLD. Liver histology assesses the amount of fat, and determines type and extent of cell injury, inflammation and fibrosis. However, liver biopsy is invasive and is limited by sampling error. Current radiological diagnostic modalities can evaluate the 'physical' morphology in liver by quantifying the backscattered US signals, but cannot interrogate the 'histochemical' components forming these backscatterers. For example, ultrasound (US) imaging can detect the presence of fat but cannot differentiate steatosis alone from steatohepatitis. Our previous study of photoacoustic physiochemical analysis (PAPCA) has demonstrated that this method can characterize the histological changes in livers during the progression of NAFLD in animal models. In this study, we will further validate PAPCA with human livers. Ex vivo human liver samples with steatosis, fibrosis and cirrhosis will be scanned using optical illumination at wavelengths of 680-1700 nm and compared to histology results. In vivo study on human subjects with confirmed steatosis is planned using our PA-ultrasound (US) parallel imaging system based on Verasonic US imaging flatform with an L7-4 probe. 10 mJ/cm2 per pulse optical energy at 755 nm will be delivered to the skin surface, which is under the safety limit of American National Standard Institute. Preliminary study with ex vivo human tissue has demonstrated the potential of the proposed approach in differentiating human liver conditions.

  11. Conditioned place avoidance of zebrafish (Danio rerio to three chemicals used for euthanasia and anaesthesia.

    Directory of Open Access Journals (Sweden)

    Devina Wong

    Full Text Available Zebrafish are becoming one of the most used vertebrates in developmental and biomedical research. Fish are commonly killed at the end of an experiment with an overdose of tricaine methanesulfonate (TMS, also known as MS-222, but to date little research has assessed if exposure to this or other agents qualifies as euthanasia (i.e. a "good death". Alternative agents include metomidate hydrochloride and clove oil. We use a conditioned place avoidance paradigm to compare aversion to TMS, clove oil, and metomidate hydrochloride. Zebrafish (n = 51 were exposed to the different anaesthetics in the initially preferred side of a light/dark box. After exposure to TMS zebrafish spent less time in their previously preferred side; aversion was less pronounced following exposure to metomidate hydrochloride and clove oil. Nine of 17 fish exposed to TMS chose not to re-enter the previously preferred side, versus 2 of 18 and 3 of 16 refusals for metomidate hydrochloride and clove oil, respectively. We conclude that metomidate hydrochloride and clove oil are less aversive than TMS and that these agents be used as humane alternatives to TMS for killing zebrafish.

  12. Effect of extraction conditions on the yield and chemical properties of pectin from cocoa husks.

    Science.gov (United States)

    Chan, Siew-Yin; Choo, Wee-Sim

    2013-12-15

    Different extraction conditions were applied to investigate the effect of temperature, extraction time and substrate-extractant ratio on pectin extraction from cocoa husks. Pectin was extracted from cocoa husks using water, citric acid at pH 2.5 or 4.0, or hydrochloric acid at pH 2.5 or 4.0. Temperature, extraction time and substrate-extractant ratio affected the yields, uronic acid contents, degrees of methylation (DM) and degrees of acetylation (DA) of the extracted pectins using the five extractants differently. The yields and uronic acid contents of the extracted pectins ranged from 3.38-7.62% to 31.19-65.20%, respectively. The DM and DA of the extracted pectins ranged from 7.17-57.86% to 1.01-3.48%, respectively. The highest yield of pectin (7.62%) was obtained using citric acid at pH 2.5 [1:25 (w/v)] at 95 °C for 3.0 h. The highest uronic acid content (65.20%) in the pectin was obtained using water [1:25 (w/v)] at 95 °C for 3.0 h. PMID:23993545

  13. Effect of Preparation Conditions on the Crystallinity of Chemically Synthesized BCNO Nanophosphor

    Institute of Scientific and Technical Information of China (English)

    Lakhwant Singh; Viblla Chopra

    2011-01-01

    The carbon based boron oxynitride (BCNO) phosphor was synthesized by solid state reaction between boric acid (H3BO3) and melamine (C3H6N6) in the molar ratios of 1:1 and 2:1 respectively at different temperatures up to 1400℃. The composition with molar ratios 1:1 of starting materials is found to be highly crystalline with an average particle size of 38 nm and the lattice constants a=b=0.251 nm and c=0.666 nm. The solid state reaction of boric acid and melamine in the composition 2:1 leads to the formation of compound in the semi-crystalline state under the same conditions of preparation, but its phase cannot be recognised. The X-ray diffraction (XRD) spectra, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) images of BCNO compound confirm the phase, nanometre size and shape respectively of synthesized material. The photoluminescence (PL) spectra of the synthesized BCNO products reveals that the electronic structure of BCNO compound can be controlled by changing the molar ratios of starting materials and heating temperatures. These synthesized compounds are very interesting and important candidate materials for light emitter.

  14. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H2SO4, even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni2(Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like μ, σ and P, may

  15. Hematopoietic stem cell cytokines and fibroblast growth factor-2 stimulate human endothelial cell-pericyte tube co-assembly in 3D fibrin matrices under serum-free defined conditions.

    Directory of Open Access Journals (Sweden)

    Annie O Smith

    Full Text Available We describe a novel 3D fibrin matrix model using recombinant hematopoietic stem cell cytokines under serum-free defined conditions which promotes the assembly of human endothelial cell (EC tubes with co-associated pericytes. Individual ECs and pericytes are randomly mixed together and EC tubes form that is accompanied by pericyte recruitment to the EC tube abluminal surface over a 3-5 day period. These morphogenic processes are stimulated by a combination of the hematopoietic stem cell cytokines, stem cell factor, interleukin-3, stromal derived factor-1α, and Flt-3 ligand which are added in conjunction with fibroblast growth factor (FGF-2 into the fibrin matrix. In contrast, this tube morphogenic response does not occur under serum-free defined conditions when VEGF and FGF-2 are added together in the fibrin matrices. We recently demonstrated that VEGF and FGF-2 are able to prime EC tube morphogenic responses (i.e. added overnight prior to the morphogenic assay to hematopoietic stem cell cytokines in collagen matrices and, interestingly, they also prime EC tube morphogenesis in 3D fibrin matrices. EC-pericyte interactions in 3D fibrin matrices leads to marked vascular basement membrane assembly as demonstrated using immunofluorescence and transmission electron microscopy. Furthermore, we show that hematopoietic stem cell cytokines and pericytes stimulate EC sprouting in fibrin matrices in a manner dependent on the α5β1 integrin. This novel co-culture system, under serum-free defined conditions, allows for a molecular analysis of EC tube assembly, pericyte recruitment and maturation events in a critical ECM environment (i.e. fibrin matrices that regulates angiogenic events in postnatal life.

  16. Evaluation of some chemical and technological properties of induced erect chickpea mutant lines developed under drought stressed conditions

    International Nuclear Information System (INIS)

    Seeds of the chickpea variety Flip 99-47 C were treated with gamma rays at doses of 0, 50 and 75 Gy and sown in the winter season of 2004/2005 to raise M1 generation under ordinary (normal) irrigation conditions. Bulked seeds from each treatment were planted in the subsequent growing seasons of 2005/2006 and 2006/2007 to advance M2 and M3 generations, respectively under either ordinary (normal) irrigation or drought stress condition. In the third generation, three erect mutant lines were derived from 75 Gy mutagenic treatment under drought stress compared to semi spreading growth habit of the initiated variety Flip 99-47 C. In the winter season of 2007/2008, M4 bulked seeds from the three erect lines as well as unirradiated seeds of the original variety grown under either ordinary (normal) irrigation (2152.5 m3/fad.) or drought (1159.2 m3/fad.) conditions were analyzed for the chemical composition and nutritional values. Obtained results indicated that there were slight decreases in protein and fat contents accompanied with marginal increases in both ash and carbohydrates in seed samples of the erect mutant developed under drought stress as compared to unirradiated seeds of the original variety grown under ordinary (normal) irrigation treatment. An opposite trend was noticed between seed samples derived from the erect lines compared to seeds of the parent variety developed under drought condition. Negligible changes in levels of the minerals (iron, magnesium, calcium and phosphorus) were detected between seeds of the erect lines and the original variety that grown under either ordinary (normal) irrigation or drought conditions. Cooking time (min) and hydration coefficient values did not much differ between the three tested seed samples. Marginal differences in essential and non-essential amino acids were detected between seeds of the erect mutants and those of the initial variety grown under ordinary (normal) irrigation or drought stressed conditions

  17. Chemical reactivity of precursor materials during synthesis of glasses used for conditioning high-level radioactive waste: Experiments and models

    International Nuclear Information System (INIS)

    The glass used to store high-level radioactive waste is produced by reaction of a solid waste residue and a glassy precursor (glass frit). The waste residue is first dried and calcined (to lose water and nitrogen respectively), then mixed with the glass frit to enable vitrification at high temperature. In order to obtain a good quality glass of constant composition upon cooling, the chemical reactions between the solid precursors must be complete while in the liquid state, to enable incorporation of the radioactive elements into the glassy matrix. The physical and chemical conditions during glass synthesis (e.g. temperature, relative proportions of frit and calcine, amount of radioactive charge) are typically empirically adjusted to obtain a satisfactory final product. The aim of this work is to provide new insights into the chemical and physical interactions that take place during vitrification and to provide data for a mathematical model that has been developed to simulate the chemical reactions. The consequences of the different chemical reactions that involve solid, liquid and gaseous phases are described (thermal effects, changes in crystal morphology and composition, variations in melt properties and structure). In a first series of experiments, a simplified analogue of the calcine (NaNO3-Al2O3 ± MoO3/Nd2O3) has been studied. In a second series of experiments, the simplified calcines have been reacted with a simplified glass frit (SiO2-Na2O-B2O3-Al2O3) at high temperature. The results show that crystallization of the calcine may take place before interaction with the glass frit, but that the reactivity with the glass at high temperature is a function of the nature and stoichiometry of the crystalline phases which form at low temperature. The results also highlight how the mixing of the starting materials, the physical properties of the frit (viscosity, glass transition temperature) and the Na2O/Al2O3 of the calcine but also its crystallization all contribute

  18. 49 CFR 173.168 - Chemical oxygen generators.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Chemical oxygen generators. 173.168 Section 173... Class 7 § 173.168 Chemical oxygen generators. An oxygen generator, chemical (defined in § 171.8 of this subchapter) may be transported only under the following conditions: (a) Approval. A chemical oxygen...

  19. Hydrogen transfer hydrocracking of C. procera latex under ambient pressure conditions to get value added chemicals and fuels

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, D.K.; Behera, B.K.; Arora, M. (Indian Institute of Technology, New Delhi (India). Fuels and Biofuels Engineering Lab.)

    1994-01-01

    Biomass is renewable source of energy while the reserves of petroleum are being depleted. The latex of a potential petrocrop, Calotropis procera, a laticifer, arid-plant which is rich in hydrocarbon type triterpene compounds etc. was found to be a better feed stock for thermal hydrocracking as compared to whole plant biomass in terms of liquid product yield. Studies of chemical reaction dynamics of the thermal cracking of latex at 200-400[degree]C showed that the process should be termed as hydrogen-transfer (H-T) hydrocracking of latex under ambient pressure conditions. The hydrogen rich cracked triterpenoids act as the H-donors in this process, where nascent hydrogen atoms and free radicals chemically plug the cracked moieties to stabilise these. Latex was also coagulated and the H-T hydrocracking of the feedstock coagulum gave a higher yield of cracked oil in comparison to that from the dried latex. The temperature for hydrocracking of latex has been optimized to 350[degree]C and molecular sieve was found to catalyse the H-T hydrocracking process to yield more liquid product. The distillation range of cracked latex oil (CLO) obtained from H-T hydrocracking of C. procera latex indicated that it can be used as fuel oil or substitute for diesel fuel. Moreover, CLO resembled diesel fuels and was predominantly paraffinic in nature as characterised by NMR and FTIR spectral analysis. A process has been recommended for getting value added fuels and chemicals from C. procera latex. 29 refs., 5 figs., 3 tabs.

  20. Effects of Calcination and Milling Process Conditions for Ceria Slurry on Shallow-Trench-Isolation Chemical-Mechanical Polishing Performance

    Science.gov (United States)

    Kim, Jun-Seok; Kang, Hyun-Goo; Kanemoto, Manabu; Paik, Ungyu; Park, Jea-Gun

    2007-12-01

    To improve the performance of shallow trench isolation chemical-mechanical polishing (STI-CMP) in terms of the removal selectivity of oxide and nitride films and the formation of surface defects, we investigated the effects of the calcination and milling process conditions during ceria slurry synthesis. We have focused on the effects of particle size distribution, the large-particle size, and the dispersion stability in a ceria slurry. We determined the optimum bead size for milling and appropriate calcination temperatures in order to obtain a reasonable particle distribution, with lower numbers of fine primary particles and large, agglomerated particles, in ceria slurry. This was achieved by reducing the quantity of aggregated particles during milling and two-step calcination process generating higher-density particles. These results can be qualitatively explained by abrasive collisions occurring between the milling beads and the decarbonation of cerium carbonate through diffusion during the manufacturing process used for the ceria slurry.

  1. Effect of vacuum conditions and plasma concentration on the chemical composition and adhesion of vacuum-plasma coatings

    Science.gov (United States)

    Borisov, D. P.; Kuznetsov, V. M.; Slabodchikov, V. A.

    2015-11-01

    The paper reports on the chemical composition of titanium nitride (TiN) and silicon (Si) coatings deposited with a new technological vacuum plasma setup which comprises magnetron sputtering systems, arc evaporators, and an efficient plasma generator. It is shown that due to highly clean vacuum conditions and highly clean surface treatment in the gas discharge plasma, both the coating-substrate interface and the coatings as such are almost free from oxygen and carbon. It is found that the coating-substrate interface represents a layer of thickness ≥ 60 nm formed through vacuum plasma mixing of the coating and substrate materials. The TiN coatings obtained on the new equipment display a higher adhesion compared to brass coatings deposited by industrial technologies via intermediate titanium oxide layers. It is concluded that the designed vacuum plasma equipment allows efficient surface modification of materials and articles by vacuum plasma immersion processes.

  2. Morphological peculiarities of chronic gastritis in children and adolescents of Belarus under conditions of low dose radiation-chemical exposure

    International Nuclear Information System (INIS)

    Following the accident at the Chernobyl nuclear power station, the unfavourable ecological situation due to chemical contamination of the environment was aggravated by the radiation effect. At present, radionuclides of caesium and lead, as well as the nitrates, are the most widely distributed ecotoxicants. Under conditions of the negative ecological effect as the result of per os penetration of the majority of xenobiotics, the gastro-intestinal tract is at particular risk. During 1990-1994, 442 children and adolescents aged 10-17 residing at the ecologically different regions of the Republic have been examined. The program of examination included morphological investigation of bioptates of the stomach mucous membrane, determination of the radiocaesium specific activity in the body and the evaluation of lead content in blood and nitrates content in urine. (author)

  3. Characterization of the ZnO thin film prepared by single source chemical vapor deposition under low vacuum condition

    Institute of Scientific and Technical Information of China (English)

    DENG; Hong(邓宏); B.; GONG; A.; J.; Petrella; J.; J.; Russell; R.; N.; Lamb

    2003-01-01

    A novel technique is developed for growing high quality ZnO thin films by means of single source chemical vapor deposition (SS CVD) under low vacuum conditions with the precursor of zinc carbamate Zn4O(CO2Net2)6. SEM, AFM and XRD studies show that the resultant thin films have high density, smooth surface, uniform polycrystalline structure and excellent c-axis orientation. XPS investigation indicates that the ZnO films are free of decomposed precursor residues in the bulk. Careful quantitative XPS analysis reveals that the ZnO films are stoichiometric with O/Zn atomic ratio very close to that of ZnO single crystal.

  4. Collisions of small ice particles under microgravity conditions (II): Does the chemical composition of the ice change the collisional properties?

    CERN Document Server

    Hill, C R; Blum, J; Fraser, H J

    2015-01-01

    Context: Understanding the collisional properties of ice is important for understanding both the early stages of planet formation and the evolution of planetary ring systems. Simple chemicals such as methanol and formic acid are known to be present in cold protostellar regions alongside the dominant water ice; they are also likely to be incorporated into planets which form in protoplanetary disks, and planetary ring systems. However, the effect of the chemical composition of the ice on its collisional properties has not yet been studied. Aims: Collisions of 1.5 cm ice spheres composed of pure crystalline water ice, water with 5% methanol, and water with 5% formic acid were investigated to determine the effect of the ice composition on the collisional outcomes. Methods: The collisions were conducted in a dedicated experimental instrument, operated under microgravity conditions, at relative particle impact velocities between 0.01 and 0.19 m s^-1, temperatures between 131 and 160 K and a pressure of around 10^-5...

  5. Studies on the phytoplankton populations and physico-chemical conditions of treated sewage discharged into Lake Manzala in Egypt.

    Science.gov (United States)

    el-Naggar, M E; Shaaban-Dessouki, S A; Abdel-Hamid, M I; Aly, E M

    1998-04-01

    Over a full year, the phytoplankton populations and physico-chemical conditions of treated sewage discharged into Lake Manzala in Egypt were investigated. Sixty-seven species of algae were identified, 18 Cyanophyta (Cyanobacteria), 19 Chlorophyta, 21 Bacillariophyta, 6 Euglenophyta, 2 Cryptophyta and one species Pyrrhophyta. Nitzschia (6 spp.), Scenedesmus (6 spp.), Navicula (4 spp.), Oscillatoria (4 spp.) and Euglena (4 spp.) were the most common genera. A remarkable seasonal variation in species composition and standing crop of the phytoplankton populations was noted during the study. The total phytoplankton standing crop appeared to be mainly dependent on the growth of certain species viz., Oscillatoria chalybea, O. princepes, O. tenuis, Microcystis aeruginosa, Anabaena constricta (Cyanophyta), Nitzschia obtusa, Bacillaria paradoxa, Cocconeis placentula, Cyclotella meneghiniana (Bacillariophyta), Pandorina morum, Volvox sp. (Chlorophyta) and Phacus curvicauda (Euglenophyta). The continuous presence of Anabaena constricta and Nitzschia palea was recorded in the treated sewage. The least represented algal divisions were Pyrrhophyta and Cryptophyta, both in terms of quality and quantity. The data indicate that the secondary effluents were unstable in their chemical features and grossly polluted. Therefore, the treatment systems must treat the discharged sewage to a tertiary level before discharging into Lake Manzala. PMID:9579343

  6. Hanford Defined Wastes model

    International Nuclear Information System (INIS)

    This paper describes the methodology behind the Hanford Defined Wastes (HDW) model for estimating the contents of Hanford high level waste (HLW) tanks. The HDW model is based on historical process and transaction histories for each tank and has four major components: Waste Status and Transaction Record Summary (WSTRS), Tank Layer Model (TLM), Supernatant Mixing Model (SMM), and HDW Compositions. Three examples of the application of HDW model estimates are described, including comparisons with global site inventories, comparisons with per tank assays, and comparisons of HDW TOC (Total Organic Carbon) estimates with existing hydrogen watch list tanks. The HDW model provides a cross check on existing assumptions for the global site inventory of wastes. Note that existing inventories for Hanford are based on much the same source information as the HDW model, chemicals used and process flowsheet data. Despite that, the HDW model predicts that the sodium inventory for Hanford tanks is 40,300 MT (metric tonnes), which is only 58% of the previous baseline estimate of 69,000 MT. There are other significant differences for inventories of chromium, iron, and nitrate as well. There are two causes for these differences; (1) previous neglect of chemical inventory placed into the ground at Hanford; (2) double counting attributed to tank inventory that was retrieved, reprocessed, and returned to the tanks. This double-counted inventory was counted once when it first went into the tanks and then again after it was reprocessed. The HDW model estimates also can provide a basis for targeting tanks for organic safety issues. In particular, the HDW model has shown that 88% of flammable gas watch list tanks have HDW estimated organic concentrations in excess of 0.64 wt% TOC. Derivation of variabilities for the HDW model estimates and other potential uses will also be outlined

  7. Testing insecticidal activity of novel chemically synthesized siRNA against Plutella xylostella under laboratory and field conditions.

    Directory of Open Access Journals (Sweden)

    Liang Gong

    Full Text Available BACKGROUND: Over the last 60 years, synthetic chemical pesticides have served as a main tactic in the field of crop protection, but their availability is now declining as a result of the development of insect resistance. Therefore, alternative pest management agents are needed. However, the demonstration of RNAi gene silencing in insects and its successful usage in disrupting the expression of vital genes opened a door to the development of a variety of novel, environmentally sound approaches for insect pest management. METHODOLOGY/PRINCIPAL FINDINGS: Six small interfering RNAs (siRNAs were chemically synthesized and modified according to the cDNA sequence of P. xylostella acetylcholine esterase genes AChE1 and AChE2. All of them were formulated and used in insecticide activity screening against P. xylostella. Bioassay data suggested that Si-ace1_003 and Si-ace2_001 at a concentration of 3 µg cm(-2 displayed the best insecticidal activity with 73.7% and 89.0%, mortality, respectively. Additional bioassays were used to obtain the acute lethal concentrations of LC50 and LC90 for Si-ace2_001, which were 53.66 µg/ml and 759.71 µg/ml, respectively. Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2 were reduced by 5.7-fold compared to the control group. Consequently, AChE activity was also reduced by 1.7-fold. Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses. Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions. CONCLUSIONS: The most important finding of this study is the discovery that chemically synthesized and modified siRNA corresponding to P. xylostella AChE genes cause significant mortality of the insect both under laboratory and field conditions, which provides a novel strategy to control P

  8. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Luo, Guang-Qian; Hu, Hong-Yun [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Qiang; Yang, Jia-Kuan [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Hong, E-mail: hyao@hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer NH{sub 3}, SO{sub 2}, H{sub 2}S and COS are emitted during different sludge conditioning processes. Black-Right-Pointing-Pointer H{sub 2}S and SO{sub 2} generation increase in the acidic environment created by H{sub 2}SO{sub 4}. Black-Right-Pointing-Pointer Fenton peroxidation facilitates the formation of COS. Black-Right-Pointing-Pointer CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. Black-Right-Pointing-Pointer CaO leads to the conversion of free ammonia or protonated amine to volatile NH{sub 3}. - Abstract: Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH{sub 3}), sulfur dioxide (SO{sub 2}), hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO{sub 2} and H{sub 2}S emissions in the H{sub 2}SO{sub 4} conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant

  9. Optimization of operational conditions for batchwise biosorption of chromium (VI) using chemically treated alstonia scholaris leaves as biosorbent

    International Nuclear Information System (INIS)

    Biosorption has attracted attention as a cost-effective tool for the treatment of metal-bearing wastewater. While using novel bio sorbents, optimization of operating conditions becomes more important for the efficiency of the process. In this study, a novel biosorbent i.e. Alstonia scholaris leaves were used for biosorption of Cr (VI) from aqueous media. The effect of various parameters, such as contact time of solution with biosorbent, temperature, pH, biosorbent dose and agitation speed were studied. A comparative study of modification of biosorbent using acid and base was also performed. It has been found that acid treated Alstonia scholaris leaves have greater biosorption capacity as compared to untreated and base treated leaves. Optimum conditions for removing Cr (VI) using acid treated biosorbent were: 0.2 g/50 mL of biosorbent, 50 deg. C temperature, 15 minutes contact time, 300 rpm stirring speed and 2.0 pH. Langmuir and Freundlich isotherms were also employed to evaluate maximum biosorption capacity of untreated and chemically treated Alstonia scholaris leaves for Cr (VI). (author)

  10. Effect of nontronite smectite clay on the chemical evolution of several organic molecules under simulated Mars surface UV radiation conditions

    Science.gov (United States)

    Poch, Olivier; Dequaire, Tristan; Stalport, Fabien; Jaber, Maguy; Lambert, Jean-François; Szopa, Cyril; Coll, Patrice

    2015-04-01

    The search for organic carbon-containing molecules at the surface of Mars, as clues of past habitability or remnants of life, is a major scientific goal for Mars exploration. Several lines of evidence, including the detection of phyllosilicates, suggest that early Mars offered favorable conditions for long-term sustaining of water. As a consequence, we can assume that in those days, endogenous chemical processes, or even primitive life, may have produced organic matter on Mars. Moreover, exogenous delivery from small bodies or dust particles is likely to have brought fresh organic molecules to the surface of Mars up today. Organic matter is therefore expected to be present at the surface/subsurface of the planet. But the current environmental conditions at the surface - UV radiation, oxidants and energetic particles - generate physico-chemical processes that may affect organic molecules. On the other hand, on Earth, phyllosilicates are known to accumulate and preserve organic matter. But are phyllosilicates efficient at preserving organic molecules under the current environmental conditions at the surface of Mars? We have monitored the qualitative and quantitative evolutions of glycine, urea and adenine interacting with the Fe3+-smectite clay nontronite, one of the most abundant phyllosilicates present at the surface of Mars, under simulated Martian surface ultraviolet light (190-400 nm), mean temperature (218 ± 2 K) and pressure (6 ± 1 mbar) in a laboratory simulation setup. We have tested organic-rich samples which may be representative of the evaporation of a warm little pond of liquid water having concentrated organics on Mars. For each molecule, we have observed how the nontronite influences the quantum efficiency of its photodecomposition and the nature of its solid evolution products. The results reveal a pronounced photoprotective effect of nontronite on the evolution of glycine and adenine: their efficiencies of photodecomposition are reduced by a factor

  11. Chemical equilibria model of strontium-90 adsorption and transport in soil in response to dynamic alkaline conditions.

    Science.gov (United States)

    Spalding, B P; Spalding, I R

    2001-01-15

    Strontium-90 is a major hazardous contaminant of radioactive wastewater and its processing sludges at many Department of Energy (DOE) facilities. In the past, such contaminated wastewater and sludge have been disposed in soil seepage pits, lagoons, or cribs often under highly perturbed alkaline conditions (pH > 12) where 90Sr solubility is low and its adsorption to surrounding soil is high. As natural weathering returns these soils to near-neutral or slightly acidic conditions, the adsorbed and precipitated calcium and magnesium phases, in which 90Sr is carried, change significantly in both nature and amounts. No comprehensive computational method has been formulated previously to quantitatively simulate the dynamics of 90Sr in the soil-groundwater environment under such dynamic and wide-ranging conditions. A computational code, the Hydrologic Utility Model for Demonstrating Integrated Nuclear Geochemical Environmental Responses (HUMDINGER), was composed to describe the changing equilibria of 90Sr in soil based on its causative chemical reactions including soil buffering, pH-dependent cation-exchange capacity, cation selectivity, and the precipitation/dissolution of calcium carbonate, calcium hydroxide, and magnesium hydroxide in response to leaching groundwater characteristics including pH, acid-neutralizing capacity, dissolved cations, and inorganic carbonate species. The code includes a simulation of one-dimensional transport of 90Sr through a soil column as a series of soil mixing cells where the equilibrium soluble output from one cell is applied to the next cell. Unamended soil leaching and highly alkaline soil treatments, including potassium hydroxide, sodium silicate, and sodium aluminate, were simulated and compared with experimental findings using large (10 kg) soil columns that were leached with 90Sr-contaminated groundwater after treatment. HUMDINGER's simulations were in good agreement with dynamic experimental observations of soil exchange capacity

  12. Mobilization and transport of metal-rich colloidal particles from mine tailings into soil under transient chemical and physical conditions.

    Science.gov (United States)

    Lu, Cong; Wu, Yaoguo; Hu, Sihai; Raza, Muhammad Ali; Fu, Yilin

    2016-04-01

    Exposed mine tailing wastes with considerable heavy metals can release hazardous colloidal particles into soil under transient chemical and physical conditions. Two-layered packed columns with tailings above and soils below were established to investigate mobilization and transport of colloidal particles from metal-rich mine tailings into soil under transient infiltration ionic strength (IS: 100, 20, 2 mM) and flow rate (FR: 20.7, 41, and 62.3 mm h(-1)), with Cu and Pb as representatives of the heavy metals. Results show that the tailing particles within the colloidal size (below 2 μm) were released from the columns. A step-decrease in infiltration IS and FR enhanced, whereas a step-increase in the IS and FR restrained the release of tailing particles from the column. The effects of step-changing FR were unexpected due to the small size of the released tailing particles (220-342 nm, being not sensitive to hydrodynamic shear force), the diffusion-controlled particle release process and the relatively compact pore structure. The tailing particles present in the solution with tested IS were found negatively charged and more stable than soil particles, which provides favorable conditions for tailing particles to be transported over a long distance in the soil. The mobilization and transport of Cu and Pb from the tailings into soil were mediated by the tailing particles. Therefore, the inherent toxic tailing particles could be considerably introduced into soil under certain conditions (IS reduction or FR decrease), which may result in serious environmental pollution. PMID:26780043

  13. Optimum synthesis conditions of nanometric Fe50Ni50 alloy formed by chemical reduction in aqueous solution

    Indian Academy of Sciences (India)

    Marwa A Mohamed; Azza H El-Maghraby; Mona M Abd El-Latif; Hassan A Farag

    2013-10-01

    In the present article, various nanometric Fe50Ni50 alloys were synthesized by chemical reduction of the corresponding metal ions, with hydrazine in an aqueous solution. Process variables of reaction temperature, pH of the hydrazine solution and concentration of metal ions were varied in order to determine the optimum synthesis conditions regarding quality, productivity and cost. It is found that pH of hydrazine solution, at low concentration of metal ions, is the most crucial variable affecting the reaction rate, average crystallite and particle sizes of the synthesized nanometric Fe50Ni50 alloy, followed by the total concentration of metal ions. Thus, increase of pH of hydrazine solution acts as an efficient stabilizer in reducing the particle size. On the contrary, at high concentration of metal ions, the structural characteristics of the nanometric Fe50Ni50 alloy are almost insensitive to reaction temperature and pH of hydrazine solution, but the reduction rate is remarkably sensitive to reaction temperature. Based on these results, it is decided that a reaction temperature of 80 °C, pH of the hydrazine solution of 12.5 and concentration of metal ions of 0.6 M represent the optimum synthesis conditions. The role of pH of hydrazine solution in reducing the alloy’s average particle size as well as efficient stabilizer confirms tremendous effect of synthesis conditions on the alloy structure and therefore, the importance of this study for industrial production of nanometric Fe50Ni50 alloy.

  14. Temperature waves in chemical reaction-diffusion-heat conduction systems with two ends respectively subject to Dirichlet and no-flux conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Taking the Lindemann model as a sample system in which there exist chemical reactions, diffusion and heat conduction, we found the theoretical framework of linear stability analysis for a unidimensional nonhomogeneous two-variable system with one end subject to Dirichlet conditions, while the other end no-flux conditions. Furthermore, the conditions for the emergence of temperature waves are found out by the linear stabiliy analysis and verified by a diagram for successive steps of evolution of spatial profile of temperature during a period that is plotted by numerical simulations on a computer. Without doubt, these results are in favor of the heat balance in chemical reactor designs.

  15. Chemical immobilization of adult female Weddell seals with tiletamine and zolazepam: effects of age, condition and stage of lactation

    Directory of Open Access Journals (Sweden)

    Harcourt Robert G

    2006-02-01

    Full Text Available Abstract Background Chemical immobilization of Weddell seals (Leptonychotes weddellii has previously been, for the most part, problematic and this has been mainly attributed to the type of immobilizing agent used. In addition to individual sensitivity, physiological status may play an important role. We investigated the use of the intravenous administration of a 1:1 mixture of tiletamine and zolazepam (Telazol® to immobilize adult females at different points during a physiologically demanding 5–6 week lactation period. We also compared performance between IV and IM injection of the same mixture. Results The tiletamine:zolazepam mixture administered intravenously was an effective method for immobilization with no fatalities or pronounced apnoeas in 106 procedures; however, there was a 25 % (one animal in four mortality rate with intramuscular administration. Induction time was slightly longer for females at the end of lactation (54.9 ± 2.3 seconds than at post-parturition (48.2 ± 2.9 seconds. In addition, the number of previous captures had a positive effect on induction time. There was no evidence for effects due to age, condition (total body lipid, stage of lactation or number of captures on recovery time. Conclusion We suggest that intravenous administration of tiletamine and zolazepam is an effective and safe immobilizing agent for female Weddell seals. Although individual traits could not explain variation in recovery time, we suggest careful monitoring of recovery times during longitudinal studies (> 2 captures. We show that physiological pressures do not substantially affect response to chemical immobilization with this mixture; however, consideration must be taken for differences that may exist for immobilization of adult males and juveniles. Nevertheless, we recommend a mass-specific dose of 0.50 – 0.65 mg/kg for future procedures with adult female Weddell seals and a starting dose of 0.50 mg/kg for other age classes and other

  16. Long-term Geochemical Transport Simulation to Evaluate Ambient Chemical Conditions at Horonobe URL Site, Hokkaido, Japan

    Science.gov (United States)

    Yamamoto, H.; Shimo, M.; Fujiwara, Y.; Kunimaru, T.; Xu, T.; Laaksoharju, M.

    2005-12-01

    JNC (Japan Nuclear Cycle Development Institute) has been planning an underground research laboratory (URL) in Horonobe, northern Hokkaido, Japan. In this study, long-term evolution of groundwater chemistry was simulated to evaluate ambient chemical conditions around the Horonobe URL site. The study area is about 8km by 4km and 2km deep region centered on the URL, in which the geology mainly consists of Pliocene diatomaceous argillaceous formations. Hydro-geochemical investigations using deep boreholes in about 3km by 3km area have suggested that groundwater chemistry around the site has been formed through the mixing of shallow fresh water and deep saline water. The deep groundwater has high salinity and differs from the present seawater in that it is highly reduced and has low pH, high bicarbonate and low magnesium concentration. Prior to the simulation, a computer code M3 (Laaksoharju et al. 1999) was used to model that the groundwater composition is affected by a two end-member mixing system. Next, the simulation of chemical changes during the intrusion of fresh water from land surface into deep saline water in the past 0.1 Ma was performed. A non-isothermal multiphase reactive geochemical transport simulation code TOUGHREACT (Xu and Press, 2001) was employed to solve the complex interplay of mass transport and chemical reaction in groundwater such as mineral dissolution/precipitation and ion exchange. The simulator was applied to a site-scale 3D geological structure model in which surface topography, the structures of geologic formations and a major fault were embedded. The results suggest that: 1) the spatial patterns of salinity and major constituents observed are in the site are generally consistent with a scenario of the intrusion of the surface fresh water into the deep saline water; 2) freshening of the deep saline water increases pH by cation exchange; 3) redox front migrates as oxidized water infiltrates from surface but is strongly buffered by reducing

  17. Chemical and technological evaluation of the Phyllanthus niruri aerial parts as a function of cultivation and harvesting conditions

    Directory of Open Access Journals (Sweden)

    Angélica G. Couto

    2013-02-01

    Full Text Available Tea from Phyllanthus niruri L., Phyllanthaceae, aerial parts is commonly used by Brazilian folk medicine for its benefits on the treatment of genitourinary disorders, for what the polyphenolic compounds are mainly responsible. The yield of such compounds may be influenced by several variables related with the plant growth. The effects of planting periods and harvesting conditions are investigated in this work, including four different seasons. The cultivation was characterized by dry mass yield of aerial parts, and the effect of pruning was analyzed. Leaves, stems and their mixtures were analyzed after drying and milling. Loss on drying and water soluble extractives were used as physical parameters for quality control. Flavonoid content and gallic acid were chosen as chemical markers for this work. The spectrophotometric trial based on the aluminum chloride complexes was applied to evaluate the total flavonoids content. Gallic acid contents were measured from the water extractive solutions by high-performance liquid chromatography. The pruning caused a positive influence on the amount of leaves and stems. The highest flavonoids and gallic acid contents were found in the leaves, which were developed over the summer and the winter, respectively, both from the second harvesting (after pruning. Chomatographic profile by HPLC was characterizes by the presence of gallic acid and two other major peaks (not identified substances, which relation was peculiar to each aerial part. In conclusion, these results suggest that even under less favorable climatic conditions, in winter, the pruning seems to cause a strong influence over the P. niruri polyphenolics production. Indeed, the total flavonoids content, as well as the HPLC profile, can be used as indicative parameters of the ratio of leaves and stem in the vegetal raw material.

  18. The radiolytic and chemical degradation of organic ion exchange resins under alkaline conditions: effect on radionuclide speciation

    Energy Technology Data Exchange (ETDEWEB)

    Loon, L. van; Hummel, W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1995-10-01

    The formation of water soluble organic ligands by the radiolytic and chemical degradation of several ion exchange resins was investigated under conditions close to those of the near field of a cementitious repository. The most important degradation products were characterised and their role on radionuclide speciation evaluated thoroughly. Irradiation of strong acidic cation exchange resins (Powdex PCH and Lewatite S-100) resulted in the formation of mainly sulphate and dissolved organic carbon. A small part of the carbon (10-20%) could be identified as oxalate. The identity of the remainder is unknown. Complexation studies with Cu{sup 2+} and Ni{sup 2+} showed the presence of two ligands: oxalate and ligand X. Although ligand X could not be identified, it could be characterised by its concentration, a deprotonation constant and a complexation constant for the NiX complex. The influence of oxalate and ligand X on the speciation of radionuclides is examined in detail. For oxalate no significant influence on the speciation of radionuclides is expected. The stronger complexing ligand X may exert some influence depending on its concentration and the values of other parameters. These critical parameters are discussed and limiting values are evaluated. In absence of irradiation, no evidence for the formation of ligands was found. Irradiation of strong basic anion exchange resins (Powdex PAO and Lewatite M-500) resulted in the formation of mainly ammonia, amines and dissolved organic carbon. Up to 50% of the carbon could be identified as methyl-, dimethyl- and trimethylamine. Complexation studies with Eu{sup 3+} showed that the complexing capacity under near field conditions was negligible. The speciation of cations such as Ag, Ni, Cu and Pd can be influenced by the presence of amins. The strongest amine-complexes are formed with Pd and therefore, as an example, the aqueous Pd-ammonia system is examined in great detail. (author) 30 figs., 10 tabs., refs.

  19. Optimization of synthesis conditions of PbS thin films grown by chemical bath deposition using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Yücel, Ersin, E-mail: dr.ersinyucel@gmail.com [Department of Physics, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey); Yücel, Yasin; Beleli, Buse [Department of Chemistry, Faculty of Arts and Sciences, Mustafa Kemal University, 31034 Hatay (Turkey)

    2015-09-05

    Highlights: • For the first time, RSM and CCD used for optimization of PbS thin film. • Tri-sodium citrate, deposition time and temperature were independent variables. • PbS thin film band gap value was 2.20 eV under the optimum conditions. • Quality of the film was improved after chemometrics optimization. - Abstract: In this study, PbS thin films were synthesized by chemical bath deposition (CBD) under different deposition parameters. Response surface methodology (RSM) was used to optimize synthesis parameters including amount of tri-sodium citrate (0.2–0.8 mL), deposition time (14–34 h) and deposition temperature (26.6–43.4 °C) for deposition of the films. 5-level-3-factor central composite design (CCD) was employed to evaluate effects of the deposition parameters on the response (optical band gap of the films). The significant level of both the main effects and the interaction are investigated by analysis of variance (ANOVA). The film structures were characterized by X-ray diffractometer (XRD). Morphological properties of the films were studied with a scanning electron microscopy (SEM). The optical properties of the films were investigated using a UV–visible spectrophotometer. The optimum amount of tri-sodium citrate, deposition time and deposition temperature were found to be 0.7 mL, 18.07 h and 30 °C respectively. Under these conditions, the experimental band gap of PbS was 2.20 eV, which is quite good correlation with value (1.98 eV) predicted by the model.

  20. Influence of annealing conditions on the crystallographic structure, chemical composition and luminescence of ZnO thin films

    International Nuclear Information System (INIS)

    ZnO thin films have many applications in semiconductor devices, such as semiconductor lasers, amplifiers, solar cells, chemical and ultraviolet sensors. We produced ZnO thin films on Si (4 0 0) substrates, using e-beam technique and subsequently annealed them under different conditions (i.e., temperature (200–800), time (60 min and 180 min) and environment (air and oxygen flow). The ZnO (0 0 2) preferred orientation which increases in intensity with annealing temperature and annealing time is deduced from X-ray diffraction (XRD) results. Dislocation density was higher for the films annealed in air which may be caused by the impurities (nitrogen and other species in the air) embedded in the film structure. No significant change in the nano-strain of each group of the samples (annealed under different conditions) was observed. The FESEM images showed a granular structure for annealed samples at 200 °C and 800 °C and a mixed structure of nanowires and nanosheets for samples annealed at 350 °C and 500 °C. Two peaks of UV emission and green emission were observed in the photoluminescence (PL) spectra of the produced samples. The UV emission increased with annealing temperature and annealing time showing higher crystal quality while the behavior of the green emission was opposite to that of the UV emission. The ZnO films resulted from annealing in the air showed stronger green emission than those annealed with flow of oxygen indicating higher impurity concentration and oxygen vacancies in the sample.

  1. The radiolytic and chemical degradation of organic ion exchange resins under alkaline conditions: effect on radionuclide speciation

    International Nuclear Information System (INIS)

    The formation of water soluble organic ligands by the radiolytic and chemical degradation of several ion exchange resins was investigated under conditions close to those of the near field of a cementitious repository. The most important degradation products were characterised and their role on radionuclide speciation evaluated thoroughly. Irradiation of strong acidic cation exchange resins (Powdex PCH and Lewatite S-100) resulted in the formation of mainly sulphate and dissolved organic carbon. A small part of the carbon (10-20%) could be identified as oxalate. The identity of the remainder is unknown. Complexation studies with Cu2+ and Ni2+ showed the presence of two ligands: oxalate and ligand X. Although ligand X could not be identified, it could be characterised by its concentration, a deprotonation constant and a complexation constant for the NiX complex. The influence of oxalate and ligand X on the speciation of radionuclides is examined in detail. For oxalate no significant influence on the speciation of radionuclides is expected. The stronger complexing ligand X may exert some influence depending on its concentration and the values of other parameters. These critical parameters are discussed and limiting values are evaluated. In absence of irradiation, no evidence for the formation of ligands was found. Irradiation of strong basic anion exchange resins (Powdex PAO and Lewatite M-500) resulted in the formation of mainly ammonia, amines and dissolved organic carbon. Up to 50% of the carbon could be identified as methyl-, dimethyl- and trimethylamine. Complexation studies with Eu3+ showed that the complexing capacity under near field conditions was negligible. The speciation of cations such as Ag, Ni, Cu and Pd can be influenced by the presence of amins. The strongest amine-complexes are formed with Pd and therefore, as an example, the aqueous Pd-ammonia system is examined in great detail. (author) 30 figs., 10 tabs., refs

  2. Optimization of synthesis conditions of PbS thin films grown by chemical bath deposition using response surface methodology

    International Nuclear Information System (INIS)

    Highlights: • For the first time, RSM and CCD used for optimization of PbS thin film. • Tri-sodium citrate, deposition time and temperature were independent variables. • PbS thin film band gap value was 2.20 eV under the optimum conditions. • Quality of the film was improved after chemometrics optimization. - Abstract: In this study, PbS thin films were synthesized by chemical bath deposition (CBD) under different deposition parameters. Response surface methodology (RSM) was used to optimize synthesis parameters including amount of tri-sodium citrate (0.2–0.8 mL), deposition time (14–34 h) and deposition temperature (26.6–43.4 °C) for deposition of the films. 5-level-3-factor central composite design (CCD) was employed to evaluate effects of the deposition parameters on the response (optical band gap of the films). The significant level of both the main effects and the interaction are investigated by analysis of variance (ANOVA). The film structures were characterized by X-ray diffractometer (XRD). Morphological properties of the films were studied with a scanning electron microscopy (SEM). The optical properties of the films were investigated using a UV–visible spectrophotometer. The optimum amount of tri-sodium citrate, deposition time and deposition temperature were found to be 0.7 mL, 18.07 h and 30 °C respectively. Under these conditions, the experimental band gap of PbS was 2.20 eV, which is quite good correlation with value (1.98 eV) predicted by the model

  3. Effects of catalyst support and chemical vapor deposition condition on synthesis of multi-walled carbon nanocoils

    International Nuclear Information System (INIS)

    Multi-walled carbon nanocoil (MWCNC) is a carbon nanotube (CNT) with helical shape. We have synthesized MWCNCs and MWCNTs hybrid by chemical vapor deposition (CVD). MWCNCs are considered to be a potential material in nanodevices, such as electromagnetic wave absorbers and field emitters. It is very important to take into account the purity of MWCNCs. In this study, we aimed to improve the composition ratio of MWCNCs to MWCNTs by changing catalyst preparation and CVD conditions. As a catalyst, Fe2O3/zeolite was prepared by dissolving Fe2O3 fine powder and Y-type zeolite (catalyst support material) in ethanol with an Fe density of 0.5wt.% and with a zeolite density of 3.5wt.%. The catalyst-coated Si substrate was transferred immediately onto a hotplate and was heated at 80°C for 5 min. Similarly, Fe2O3/Al2O3, Co/zeolite/Al2O3, Co/zeolite, and Co/Al2O3 were prepared. The effect of the difference of the composite catalysts on synthesis of MWCNCs was considered. The CVD reactor was heated in a tubular furnace to 660-790°C in a nitrogen atmosphere at a flow rate of 1000 ml/min. Subsequently, acetylene was mixed with nitrogen at a flow rate ratio of C2H2/N2 = 0.02-0.1. The reaction was kept under these conditions for 10 min. MWCNTs and MWCNCs were well grown by the catalysts of Co/zeolite and Co/Al2O3. The composition ratio of MWCNCs to MWCNTs was increased by using a combination of zeolite and Al2O3. The highest composition ratio of MWCNCs to MWCNTs was 12%

  4. Definable deduction relation

    Institute of Scientific and Technical Information of China (English)

    张玉平

    1999-01-01

    The nonmonotonic deduction relation in default reasoning is defined with fixed point style, which has the many-extension property that classical logic is not possessed of. These two kinds of deductions both have boolean definability property, that is, their extensions or deductive closures can be defined by boolean formulas. A generalized form of fixed point method is employed to define a class of deduction relations, which all have the above property. Theorems on definability and atomless boolean algebras in model theory are essential in dealing with this assertion.

  5. Estimating the NH3:H2SO4 ratio of nucleating clusters in atmospheric conditions using quantum chemical methods

    Directory of Open Access Journals (Sweden)

    M. Kulmala

    2007-05-01

    Full Text Available We study the ammonia addition reactions of H2SO4·NH3 molecular clusters containing up to four ammonia and two sulfuric acid molecules using the ab initio method RI-MP2 (Resolution of Identity 2nd order Møller-Plesset perturbation theory. Together with results from previous studies, we use the computed values to estimate an upper limit for the ammonia content of small atmospheric clusters, without having to explicitly include water molecules in the quantum chemical simulations. Our results indicate that the NH3:H2SO4 mole ratio of small molecular clusters in typical atmospheric conditions is probably around 1:2. High ammonia concentrations or low temperatures may lead to the formation of ammonium bisulfate (1:1 clusters, but our results rule out the formation of ammonium sulfate clusters (2:1 anywhere in the atmosphere. A sensitivity analysis indicates that the qualitative conclusions of this study are not affected even by relatively large errors in the calculation of electronic energies or vibrational frequencies.

  6. The chemical equilibrium under non-ideal conditions: industrial applications; El equilibrio quimico bajo condiciones no ideales: aplicaciones industriales

    Energy Technology Data Exchange (ETDEWEB)

    Silva Martinez, Susana; Alvarez Gallegos, Alberto; Quere, Alain [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-05-01

    In this paper is described the application of a computer program to the chemical equilibrium in non-ideal conditions (aqueous solutions of multicomponent electrolytes in the ionic forces interval: 0 < 1 < 6 mol/Kg H{sub 2}O and temperatures close to 25 celsius degrees), and its importance at industrial scale. The calculation of the thermodynamic properties of the solution (activity coefficients, osmotic coefficient, and water activity) is based in one of the most modern theories of the electrolytes; the theoretical results, compared with the experimental ones have an error of 10% or better. [Espanol] En este trabajo se describe la aplicacion de un programa de computo al equilibrio quimico en condiciones no ideales (soluciones acuosas de electrolitos multicomponentes en el intervalo de fuerzas ionicas: 0 < 1 < 6 mol/Kg H{sub 2}O y temperaturas cercanas a 25 grados celsius) y su importancia a escala industrial. El calculo de las propiedades termodinamicas (coeficientes de actividad, coeficiente osmotico y actividad del agua) de la solucion, esta basado en una de las teorias mas modernas de los electrolitos; los resultados teoricos comparados con los experimentales tienen un error del 10% o mejor.

  7. Solubility of the products of steel corrosion under conditions simulating various water-chemical regimes of power plants

    International Nuclear Information System (INIS)

    Two steps may be singled out in this proposed approach to formulation of an informationally controlling model of the water-chemical regime of the circuit. The first is calculation of the solubility of the corrosion products (singly or jointly) under circulation conditions, and the second is establishment, on the basis of a physicochemical model, of quantitative relationships between the solubility, corrosion, and mass transfer of the CP of the structural material. This approach proved successful, i.e., a quantitatively calculable relationship exists between intracircuit corrosion-erosion processes and the equilibrium solubility of the stable corrosion product or a corrosion product controlling the solubility or iron. The present communication is concerned only with examination of the solubility of the products of iron corrosion. The degree of development of the model and the ultimate aim of the predication are determined by the problem at hand. The calculations presented may serve as the fundamental basis for construction of a complete model of mass transfer of CP in the circuits, supplementation of which by thermal hydraulic, including purely mathematical, modeling would lead to creation of information-control systems for maintaining the quality of the WCR of operating power plants

  8. Quality of cowpea seeds treated with chemicals and stored in controlled and uncontrolled temperature and humidity conditions

    Directory of Open Access Journals (Sweden)

    Lucicléia Mendes de Oliveira

    2015-06-01

    Full Text Available The cowpea is a Fabaceae originated in Africa cultivated in the northern and northeastern of Brazil, where stands out as the main source of protein for the population. For the establishment of culture, seeds are treated to control and prevent pest attacks and diseases, can also attach nutrients to the seeds which will be available for plant development. The objective of the research was to evaluate the performance of cowpea seeds treated with chemical products and stored in controlled and uncontrolled temperature and humidity conditions. The following seeds treatments were applied: control (no treatment; micronutrient Comol 118, insecticide thiamethoxam, fipronil and pyraclostrobin+thiophanate-methyl and imidacloprid+thiodicarb were then stored in a cold environment and natural. The assessment of physiological seed quality was made initially and every 45 days through the germination and vigor. Among all products used, the imidacloprid + thiodicarb and fipronil + pyraclostrobin + thiophanate methyl provides stimulating effect on seed performance; seeds treated with thiamethoxam were less affected by storage than the untreated seeds; seeds treated with micronutrients exhibits similar behavior to untreated seeds and storage in a controlled environment better preserves the seed physiological quality.

  9. Chemical composition and anticancer activity of essential oils of Mediterranean sage (Salvia officinalis L.) grown in different environmental conditions.

    Science.gov (United States)

    Russo, Alessandra; Formisano, Carmen; Rigano, Daniela; Senatore, Felice; Delfine, Sebastiano; Cardile, Venera; Rosselli, Sergio; Bruno, Maurizio

    2013-05-01

    Salvia officinalis L. can be found worldwide and its leaves are commonly used as ingredient in food industry. Sage essential oil is applied in the treatment of a range of diseases and has been shown to possess different biological activities. The objectives of our research were to study the effects of environment on crop, chemical composition and anticancer activity on S. officinalis essential oil. Sage was cultivated at eighteen experimental sites in south-central Italy (Molise) in different growing environments. The essential oils (S1-S18), extracted by hydrodistillation, were analyzed by GC and CG/MS. Results show that the main components were α-thujone, camphor, borneol, γ-muurolene and sclareol for all the samples, but the percentages of these compounds varied depending on environmental factors such as altitude, water availability and pedo-climatic conditions. The growth-inhibitory and proapoptotic effects of the eighteen sage essential oils were evaluated in three human melanoma cell lines, A375, M14, and A2058. PMID:23291326

  10. Impact of chemical and meteorological boundary and initial conditions on air quality modeling: WRF-Chem sensitivity evaluation for a European domain

    Science.gov (United States)

    Ritter, Mathias; Müller, Mathias D.; Jorba, Oriol; Parlow, Eberhard; Liu, L.-J. Sally

    2013-01-01

    This study evaluates the impact of different chemical and meteorological boundary and initial conditions on the state-of-the-art Weather Research and Forecasting (WRF) model with its chemistry extension (WRF-Chem). The evaluation is done for July 2005 with 50 km horizontal resolution. The effect of monthly mean chemical boundary conditions derived from the chemical transport model LMDZ-INCA on WRF-Chem is evaluated against the effect of the preset idealized profiles. Likewise, the impact of different meteorological initial and boundary conditions (GFS and Reanalysis II) on the model is evaluated. Pearson correlation coefficient between these different runs range from 0.96 to 1.00. Exceptions exists for chemical boundary conditions on ozone and for meteorological boundary conditions on PM10, where coefficients of 0.90 were obtained. Best results were achieved with boundary and initial conditions from LMDZ-INCA and GFS. Overall, the European simulations show encouraging results for observed air pollutant, with ozone being the most and PM10 being the least satisfying.

  11. Integrated use of plant growth promoting rhizobacteria, biogas slurry and chemical nitrogen for sustainable production of maize under salt-affected conditions

    International Nuclear Information System (INIS)

    Salinity is one of the most critical constraints hampering agricultural production throughout the world, including Pakistan. Some plant growth promoting rhizobacteria (PGPR) have the ability to reduce the deleterious effect of salinity on plants due to the presence of ACC-deaminase enzyme along with some other mechanisms. The integrated use of organic, chemical and biofertilizers can reduce dependence on expensive chemical inputs. To sustain high crop yields without deterioration of soil fertility, it is important to work out optimal combination of chemical and biofertilizers, and manures in the cropping system. A pot trial was conducted to study the effect of integrated use of PGPR, chemical nitrogen, and biogas slurry for sustainable production of maize under salt-stressed conditions and for good soil health. Results showed that sole application of PGPR, chemical nitrogen and biogas slurry enhanced maize growth but their combined application was more effective. Maximum improvement in maize growth, yield, ionic concentration in leaves and nutrient concentration in grains was observed in the treatment where PGPR and biogas slurry was used in the presence of 100% recommended nitrogen as chemical fertilizer. It also improved the soil pH, ECe, and available N, P and K contents. It is concluded that integrated use of PGPR, biogas slurry and chemical nitrogen not only enhanced maize growth, yield and quality but also improved soil health. So, it may be evaluated under field conditions to get sustained yield of maize from salt-affected soils. (author)

  12. Defining Quantum Control Flow

    OpenAIRE

    Ying, Mingsheng; Yu, Nengkun; Feng, Yuan

    2012-01-01

    A remarkable difference between quantum and classical programs is that the control flow of the former can be either classical or quantum. One of the key issues in the theory of quantum programming languages is defining and understanding quantum control flow. A functional language with quantum control flow was defined by Altenkirch and Grattage [\\textit{Proc. LICS'05}, pp. 249-258]. This paper extends their work, and we introduce a general quantum control structure by defining three new quantu...

  13. Evolution of Chemical Composition, Morphology, and Photovoltaic Efficiency of CH 3 NH 3 PbI 3 Perovskite under Ambient Conditions

    KAUST Repository

    Huang, Weixin

    2016-01-12

    © 2015 American Chemical Society. The surface composition and morphology of CH3NH3PbI3 perovskite films stored for several days under ambient conditions were investigated by X-ray photoelectron spectroscopy, scanning electron microscopy, and X-ray diffraction techniques. Chemical analysis revealed the loss of CH3NH3 + and I- species from CH3NH3PbI3 and its subsequent decomposition into lead carbonate, lead hydroxide, and lead oxide. After long-term storage under ambient conditions, morphological analysis revealed the transformation of randomly distributed defects and cracks, initially present in the densely packed crystalline structure, into relatively small grains. In contrast to PbI2 powder, CH3NH3PbI3 exhibited a different degradation trend under ambient conditions. Therefore, we propose a plausible CH3NH3PbI3 decomposition pathway that explains the changes in the chemical composition of CH3NH3PbI3 under ambient conditions. In addition, films stored under such conditions were incorporated into photovoltaic cells, and their performances were examined. The chemical changes in the decomposed films were found to cause a significant decrease in the photovoltaic efficiency of CH3NH3PbI3.

  14. PLD deposition of tungsten carbide contact for diamond photodiodes. Influence of process conditions on electronic and chemical aspects

    International Nuclear Information System (INIS)

    Tungsten carbide, WC, contacts behave as very reliable Schottky contacts for opto-electronic diamond devices. Diamond is characterized by superior properties in high-power, high frequency and high-temperature applications, provided that thermally stable electrode contacts will be realized. Ohmic contacts can be easily achieved by using carbide-forming metals, while is difficult to get stable Schottky contacts at elevated temperatures, due to the interface reaction and/or inter-diffusion between metals and diamond. Novel type of contacts, made of tungsten carbide, WC, seem to be the best solution, for their excellent thermal stability, high melting point, oxidation and radiation resistance and good electrical conductivity. Our research was aimed at using pulsed laser deposition for WC thin film deposition, optimizing experimental parameters, to obtain a final device characterized by excellent electronic properties, as a detector for radiation in deep UV or as X-ray dosimeter. We deposited our films by laser ablation from a target of pure WC, using different reaction conditions (i.e., substrate heating, vacuum or reactive atmosphere (CH4/Ar), RF plasma activated), to optimize both the stoichiometry of the film and its structure. Trying to obtain a material with the best electronic response, we used also two sources of laser radiation for target ablation, i.e., nano-second pulsed excimer laser ArF, and ultra-short fs Ti:Sapphire laser. The structure and chemical aspects have been evaluated by Raman and X-ray photoelectron spectroscopy (XPS), while the dosimeter photodiode response has been tested by the I–V measurements, under soft X-ray irradiation.

  15. PLD deposition of tungsten carbide contact for diamond photodiodes. Influence of process conditions on electronic and chemical aspects

    Science.gov (United States)

    Cappelli, E.; Bellucci, A.; Orlando, S.; Trucchi, D. M.; Mezzi, A.; Valentini, V.

    2013-08-01

    Tungsten carbide, WC, contacts behave as very reliable Schottky contacts for opto-electronic diamond devices. Diamond is characterized by superior properties in high-power, high frequency and high-temperature applications, provided that thermally stable electrode contacts will be realized. Ohmic contacts can be easily achieved by using carbide-forming metals, while is difficult to get stable Schottky contacts at elevated temperatures, due to the interface reaction and/or inter-diffusion between metals and diamond. Novel type of contacts, made of tungsten carbide, WC, seem to be the best solution, for their excellent thermal stability, high melting point, oxidation and radiation resistance and good electrical conductivity. Our research was aimed at using pulsed laser deposition for WC thin film deposition, optimizing experimental parameters, to obtain a final device characterized by excellent electronic properties, as a detector for radiation in deep UV or as X-ray dosimeter. We deposited our films by laser ablation from a target of pure WC, using different reaction conditions (i.e., substrate heating, vacuum or reactive atmosphere (CH4/Ar), RF plasma activated), to optimize both the stoichiometry of the film and its structure. Trying to obtain a material with the best electronic response, we used also two sources of laser radiation for target ablation, i.e., nano-second pulsed excimer laser ArF, and ultra-short fs Ti:Sapphire laser. The structure and chemical aspects have been evaluated by Raman and X-ray photoelectron spectroscopy (XPS), while the dosimeter photodiode response has been tested by the I-V measurements, under soft X-ray irradiation.

  16. Effects of catalyst support and chemical vapor deposition condition on synthesis of multi-walled carbon nanocoils

    Energy Technology Data Exchange (ETDEWEB)

    Suda, Yoshiyuki, E-mail: suda@ee.tut.ac.jp; Iida, Tetsuo; Takikawa, Hirofumi; Harigai, Toru [Department of Electrical and Electronic Information Engineering, Toyohashi University of Technology, Toyohashi, Aichi 441-8580 (Japan); Ue, Hitoshi [Fuji Research Laboratory, Tokai Carbon Co., Ltd., Oyama, Shizuoka 410-1431 (Japan); Umeda, Yoshito [Toho Gas Co., Ltd., Tokai, Aichi 476-8501 (Japan)

    2016-02-01

    Multi-walled carbon nanocoil (MWCNC) is a carbon nanotube (CNT) with helical shape. We have synthesized MWCNCs and MWCNTs hybrid by chemical vapor deposition (CVD). MWCNCs are considered to be a potential material in nanodevices, such as electromagnetic wave absorbers and field emitters. It is very important to take into account the purity of MWCNCs. In this study, we aimed to improve the composition ratio of MWCNCs to MWCNTs by changing catalyst preparation and CVD conditions. As a catalyst, Fe{sub 2}O{sub 3}/zeolite was prepared by dissolving Fe{sub 2}O{sub 3} fine powder and Y-type zeolite (catalyst support material) in ethanol with an Fe density of 0.5wt.% and with a zeolite density of 3.5wt.%. The catalyst-coated Si substrate was transferred immediately onto a hotplate and was heated at 80°C for 5 min. Similarly, Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3}, Co/zeolite/Al{sub 2}O{sub 3}, Co/zeolite, and Co/Al{sub 2}O{sub 3} were prepared. The effect of the difference of the composite catalysts on synthesis of MWCNCs was considered. The CVD reactor was heated in a tubular furnace to 660-790°C in a nitrogen atmosphere at a flow rate of 1000 ml/min. Subsequently, acetylene was mixed with nitrogen at a flow rate ratio of C{sub 2}H{sub 2}/N{sub 2} = 0.02-0.1. The reaction was kept under these conditions for 10 min. MWCNTs and MWCNCs were well grown by the catalysts of Co/zeolite and Co/Al{sub 2}O{sub 3}. The composition ratio of MWCNCs to MWCNTs was increased by using a combination of zeolite and Al{sub 2}O{sub 3}. The highest composition ratio of MWCNCs to MWCNTs was 12%.

  17. Volatile chemical spoilage indexes of raw Atlantic salmon (salmo salar)stored under aerobic condition in relation to microbiological and sensory shelf lives

    Science.gov (United States)

    The purpose of this investigation was to identify and quantify the volatile chemical spoilage indexes (CSIs) for raw Atlantic salmon (Salmo salar) fillets stored under aerobic storage conditions at 4, 10 and 21 degrees C in relation to the determined microbial and sensory shelf lives. The volatile o...

  18. Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel engine-like conditions using integrated CFD-chemical kinetics

    DEFF Research Database (Denmark)

    Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore;

    2016-01-01

    skeletal model are close to those produced by the larger and more comprehensive chemical mechanisms, apart from those at the low pressure condition. The current study also demonstrates that the variation of averaged soot volume fraction with respect to the change of combustion chamber pressure captured...

  19. The effect of radiation-sterilization conditions and preservation procedures on physico-chemical and biological properties of bone allografts

    International Nuclear Information System (INIS)

    -nation, even after irradiation with a dose of 50 kGy. In lyophilized samples irradiated at room temp. a striking increase of collagen solubility was noted: 12-fold and 27-fold after the dose of 35 and 5OkGy, respectively, while in frozen samples the solubility of collagen was only 3-times higher than in non-irradiated controls. It has been found that radiation-induced damage of bone grafts depends mainly on two groups of factors: a/conditions of irradiation (dose, temperature), b/ physical state of bone samples: particularly the presence or absence of water. Radiation-induced damage of frozen samples may be as much as 4-times lover, if related to the damage rate at room temp. The presence of water in irradiated specimens might also strongly influence the nature of chemical reactions involved and may diminish the radiation damage

  20. Modular Software-Defined Radio

    Directory of Open Access Journals (Sweden)

    Rhiemeier Arnd-Ragnar

    2005-01-01

    Full Text Available In view of the technical and commercial boundary conditions for software-defined radio (SDR, it is suggestive to reconsider the concept anew from an unconventional point of view. The organizational principles of signal processing (rather than the signal processing algorithms themselves are the main focus of this work on modular software-defined radio. Modularity and flexibility are just two key characteristics of the SDR environment which extend smoothly into the modeling of hardware and software. In particular, the proposed model of signal processing software includes irregular, connected, directed, acyclic graphs with random node weights and random edges. Several approaches for mapping such software to a given hardware are discussed. Taking into account previous findings as well as new results from system simulations presented here, the paper finally concludes with the utility of pipelining as a general design guideline for modular software-defined radio.

  1. How to define surveillance?

    Directory of Open Access Journals (Sweden)

    Christian Fuchs

    2011-12-01

    Full Text Available The task of this paper is to explore and compare ways of defining surveillance. In order to give meaning to concepts that describe the realities of society, social theory is needed. Therefore social theory is employed in this paper for discussing ways of defining surveillance. “Living in ‘surveillance societies’ may throw up challenges of a fundamental – ontological – kind” (Lyon, 1994, p.19. Social theory is a way of clarifying such ontological questions that concern the basic nature and reality of surveillance. A distinction between neutral and negative concepts of surveillance is drawn. Some potential disadvantages of neutral concepts of surveillance are outlined. This paper wants to contribute to the discussion of how to best define surveillance and wants to show that one of the main theoretical differences and questions in surveillance theory is if surveillance should be defined as a negative or a neutral concept.

  2. Defining Documentary Film

    DEFF Research Database (Denmark)

    Juel, Henrik

    2006-01-01

    A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film......A discussion of various attemts at defining documentary film regarding form, content, truth, stile, genre or reception - and a propoposal of a positive list of essential, but non-exclusive characteristica of documentary film...

  3. Interpolation and Definability

    Science.gov (United States)

    Gabbay, Dov M.; Maksimova, Larisa L.

    This chapter is on interpolation and definability. This notion is not only central in pure logic, but has significant meaning and applicability in all areas where logic itself is applied, especially in computer science, artificial intelligence, logic programming, philosophy of science and natural language. The notion may sometimes appear to the reader as too technical/mathematical but it does also have a general meaning in terms of expressibility and definability.

  4. Modelling the growth/no growth boundary of Zygosaccharomyces bailii in acidic conditions: a contribution to the alternative method to preserve foods without using chemical preservatives.

    Science.gov (United States)

    Dang, T D T; Mertens, L; Vermeulen, A; Geeraerd, A H; Van Impe, J F; Debevere, J; Devlieghere, F

    2010-01-31

    The aim of the study was to develop mathematical models describing growth/no growth (G/NG) boundaries of the highly resistant food spoilage yeast-Zygosaccharomyces bailii-in different environmental conditions, taking acidified sauces as the target product. By applying these models, the stability of products with characteristics within the investigated pH, a(w) and acetic acid ranges can be evaluated. Besides, the well-defined no growth regions can be used in the development of guidelines regarding formulation of new shelf-stable foods without using chemical preservatives, which would facilitate the innovation of additive-free products. Experiments were performed at different temperatures and periods (22 degrees C for 45 and 60days, 30 degrees C for 45days) in 150 modified Sabouraud media characterized by high amount of sugars (glucose and fructose, 15% (w/v)), acetic acid (0.0-2.5% (v/v), 6 levels), pH (3.0-5.0, 5 levels) and a(w) (0.93-0.97, 5 levels). These time and temperature combinations were chosen as they are commonly applied for shelf-stable foods. The media were inoculated with ca. 4.5 log CFU/ml and yeast growth was monitored daily using optical density measurements. Every condition was examined in 20 replicates in order to yield accurate growth probabilities. Three separate ordinary logistic regression models were developed for different tested temperatures and incubation time. The total acetic acid concentration was considered as variable for all models. In general, when one intrinsic inhibitory factor became more stringent, the G/NG boundary shifted to less stressful conditions of the other two factors, resulting in enlarged no growth zones. Abrupt changes of growth probability often occurred around the transition zones (between growth and no growth regions), which indicates that minor variations in environmental conditions near the G/NG boundaries can cause a significant impact on the growth probability. When comparing growth after 45days between the

  5. AIDS defining disease: Disseminated cryptococcosis

    Directory of Open Access Journals (Sweden)

    Roshan Anupama

    2006-01-01

    Full Text Available Disseminated cryptococcosis is one of the acquired immune deficiency syndrome defining criteria and the most common cause of life threatening meningitis. Disseminated lesions in the skin manifest as papules or nodules that mimic molluscum contagiosum (MC. We report here a human immunodeficiency virus positive patient who presented with MC like lesions. Disseminated cryptococcosis was confirmed by India ink preparation and histopathology. The condition of the patient improved with amphotercin B.

  6. Effects of soil water conditions and organic and chemical fertilizers on growth characteristics and water use efficiency of rice in an alkaline non-calcareous soil

    Directory of Open Access Journals (Sweden)

    M. Abbasi

    2012-12-01

    Full Text Available In a greenhouse research, the effects of soil water conditions, sewage sludge and chemical fertilizers on growth characteristics and water use efficiency of rice (Oryza sativa L. cv. Ali Kazemi were studied in a loamy sand alkaline non-calcareous soil. The study was performed as a factorial experiment in a randomized complete blocks design including soil water conditions in three levels (continuous submergence, alternate submergence and alternate saturation and source and amount of organic and chemical fertilizers in 10 levels [control, 100% chemical fertilizers (434.8 mg urea, 66.1 mg KH2PO4, 40 mg KCl, 50 mg FeSO4.7H2O, 38.5 mg FeSO4.7H2O, 21.3 mg ZnSO4.7H2O and 7.9 mg CuSO4.5H2O per kg of soil, 20 g sewage sludge per kg of soil with and without 50% of chemical fertilizers, 40 g sewage sludge per kg of soil with and without 50% of chemical fertilizers, 20 g poultry manure per kg of soil with and without 50% of chemical fertilizers and 40 g poultry manure per kg of soil with and without 50% of chemical fertilizers] with three replications. At the end of growth period, tiller and leaf number per plant, length and diameter of stem, length and volume of roots, and shoot and root dry matter were measured and water use efficiency (WUE was calculated. The results showed that application of 20 and 40 g poultry manure per kg of soil prevented the growth of rice due to increase of soil salinity. Application of 20 and 40 g sewage sludge per kg of soil increased significantly tiller and leaf number per plant, length and diameter of stem, length and volume of roots, shoot and root dry matter and WUE compared to control and 100% chemical fertilizers treatments. Addition of 50% chemical fertilizers to 40 g sewage sludge per kg of soil did not significantly affect tiller and leaf number per plant, stem length, volume of roots, shoot dry matter and WUE of rice. The highest tiller number per plant, stem diameter, root length and the ratio of shoot dry matter to

  7. Hemp raw materials: The effect of cultivar, growth conditions and pretreatment on the chemical composition of the fibres

    OpenAIRE

    Thomsen, A.B.; Rasmussen, S.K.; Bohn, V.; Nielsen, K.V.; Thygesen, A.

    2005-01-01

    Hemp raw materials were analyzed chemically to determine their content of cellulose, hemicellulose, lignin and ashes. Correction for ashes was only necessary in the first step of the chemical analysis: the Neutral Detergent Fibre step. The hemp fiberscontained 73-77% w/w cellulose, 7-9% w/w hemicellulose and 4-6% w/w lignin, while the hemp shives contained 48% w/w cellulose, 21-25% w/w hemicellulose and 17-19% w/w lignin. Among the four investigated cultivars, Felina contained least lignin, w...

  8. Can play be defined?

    DEFF Research Database (Denmark)

    Eichberg, Henning

    2015-01-01

    Can play be defined? There is reason to raise critical questions about the established academic demand that at phenomenon – also in humanist studies – should first of all be defined, i.e. de-lineated and by neat lines limited to a “little box” that can be handled. The following chapter develops the...... critical argument against this academic technique by going back to the history of cultural anthropology of play. This history did not develop in a linear way, but by shifts between different periods of colonial and anticolonial positions, as well as between more positivistic and more relativist approaches...... construction. Human beings can very well understand play – or whatever phenomenon in human life – without defining it....

  9. Experimental paradigm for in-lab proxy aquatic studies under conditions of static, non flow through chemical exposures

    Science.gov (United States)

    Endocrine disrupting chemicals (EDCs) such as 17α ethynylestradiol (EE2), 17β estradiol (E2), estrone (E1) and para-nonylphenol (NP) have been measured in wastewater treatment plant effluents, surface waters, sediments and sludge, and have been shown to induce liver-sp...

  10. Defining Data Science

    OpenAIRE

    Zhu, Yangyong; Xiong, Yun

    2015-01-01

    Data science is gaining more and more and widespread attention, but no consensus viewpoint on what data science is has emerged. As a new science, its objects of study and scientific issues should not be covered by established sciences. Data in cyberspace have formed what we call datanature. In the present paper, data science is defined as the science of exploring datanature.

  11. Defining Game Mechanics

    DEFF Research Database (Denmark)

    Sicart (Vila), Miguel Angel

    2008-01-01

    This article defins game mechanics in relation to rules and challenges. Game mechanics are methods invoked by agents for interacting with the game world. I apply this definition to a comparative analysis of the games Rez, Every Extend Extra and Shadow of the Colossus that will show the relevance...... of a formal definition of game mechanics. Udgivelsesdato: Dec 2008...

  12. On Defining Mass

    Science.gov (United States)

    Hecht, Eugene

    2011-01-01

    Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement…

  13. Integrative STEM Education Defined

    OpenAIRE

    Sanders, Mark E.

    2013-01-01

    "In operationally defining integrative STEM education, we hope to avoid the gross confusion/ambiguity associated with STEM education. Those who wish to use integrative STEM education to describe instruction must be certain that instruction is grounded in the context of technological/engineering design activity.

  14. Unlocking the Sporicidal Potential of Ethanol: Induced Sporicidal Activity of Ethanol against Clostridium difficile and Bacillus Spores under Altered Physical and Chemical Conditions.

    Directory of Open Access Journals (Sweden)

    Michelle M Nerandzic

    Full Text Available Due to their efficacy and convenience, alcohol-based hand sanitizers have been widely adopted as the primary method of hand hygiene in healthcare settings. However, alcohols lack activity against bacterial spores produced by pathogens such as Clostridium difficile and Bacillus anthracis. We hypothesized that sporicidal activity could be induced in alcohols through alteration of physical or chemical conditions that have been shown to degrade or allow penetration of spore coats.Acidification, alkalinization, and heating of ethanol induced rapid sporicidal activity against C. difficile, and to a lesser extent Bacillus thuringiensis and Bacillus subtilis. The sporicidal activity of acidified ethanol was enhanced by increasing ionic strength and mild elevations in temperature. On skin, sporicidal ethanol formulations were as effective as soap and water hand washing in reducing levels of C. difficile spores.These findings demonstrate that novel ethanol-based sporicidal hand hygiene formulations can be developed through alteration of physical and chemical conditions.

  15. Chemical composition and bioactive compounds of garlic (Allium sativum L.) as affected by pre- and post-harvest conditions: A review.

    Science.gov (United States)

    Martins, Natália; Petropoulos, Spyridon; Ferreira, Isabel C F R

    2016-11-15

    Garlic (Allium sativum L.) is considered one of the twenty most important vegetables, with various uses throughout the world, either as a raw vegetable for culinary purposes, or as an ingredient of traditional and modern medicine. Furthermore, it has also been proposed as one of the richest sources of total phenolic compounds, among the usually consumed vegetables, and has been highly ranked regarding its contribution of phenolic compounds to human diet. This review aims to examine all the aspects related with garlic chemical composition and quality, focusing on its bioactive properties. A particular emphasis is given on the organosulfur compounds content, since they highly contribute to the effective bioactive properties of garlic, including its derived products. The important effects of pre-harvest (genotype and various cultivation practices) and post-harvest conditions (storage conditions and processing treatments) on chemical composition and, consequently, bioactive potency of garlic are also discussed. PMID:27283605

  16. Understanding and modeling of chemical transition of nitrate accompanied with corrosion of carbon steel under hyper-alkaline and high nitrate concentration conditions

    International Nuclear Information System (INIS)

    Chemical reactions between metal and nitrate ion have been studied to determine their roles in chemical conditioning of a radioactive waste disposal repository and its surrounding environment. Immersion tests and rest potential measurements under hyper-alkaline and high NaNO3 concentration conditions were conducted to elucidate and improve model predictions of chemical interactions between carbon steel and NO3- in highly concentrated solutions of nitrate salts. Potentiostatic electrolysis experiments in the concentrated solution with a carbon steel electrode, as the working electrode, were also conducted to determine the electrochemical rate equation for NO3- reduction to NO2-. Experimental results of potentiostatic electrolysis of the concentrated solutions showed that a linear electrochemical rate equation for NO3- reduction to NO2-, as used in the previous model, gave too high a rate under the conditions of high NaNO3 concentration (≥1 mol dm-3). To ameliorate this effect, a non-linear equation was derived assuming a Langmuir type adsorption process of NO3- as a precursor process of discharge, and the parameter for the equation was determined by curve fitting using the data acquired under the conditions of potential -0.85 V vs. SHE and pH 12.5. The equation was incorporated in the model, and was used to analyze the results of ampul tests and rest potential measurements. The modified model can estimate the tendency of time dependent variation of chemical species and of rest potentials in the highly concentrated solution of NaNO3. (author)

  17. Chemical Composition and Biological Activity of Essential Oils of Origanum vulgare L. subsp. vulgare L. under Different Growth Conditions

    Directory of Open Access Journals (Sweden)

    Enrica De Falco

    2013-12-01

    Full Text Available This research was aimed at investigating the essential oil production, chemical composition and biological activity of a crop of pink flowered oregano (Origanum vulgare L. subsp. vulgare L. under different spatial distribution of the plants (single and binate rows. This plant factor was shown to affect its growth, soil covering, fresh biomass, essential oil amount and composition. In particular, the essential oil percentage was higher for the binate row treatment at the full bloom. The chemical composition of the oils obtained by hydrodistillation was fully characterized by GC and GC-MS. The oil from plants grown in single rows was rich in sabinene, while plants grown in double rows were richer in ocimenes. The essential oils showed antimicrobial action, mainly against Gram-positive pathogens and particularly Bacillus cereus and B. subtilis.

  18. Hadron multiplicities and chemical freeze-out conditions in proton-proton and nucleus-nucleus collisions

    Science.gov (United States)

    Vovchenko, V.; Begun, V. V.; Gorenstein, M. I.

    2016-06-01

    New results of the NA61/SHINE Collaboration at the CERN SPS on mean hadron multiplicities in proton-proton (p+p) interactions are analyzed within the transport models and the hadron resonance gas (HRG) statistical model. The chemical freeze-out parameters in p+p interactions and central Pb+Pb (or Au+Au) collisions are found and compared with each other in the range of the center-of-mass energy of the nucleon pair √{sN N}=3.2 -17.3 GeV. The canonical ensemble formulation of the HRG model is used to describe mean hadron multiplicities in p+p interactions and the grand canonical ensemble in central Pb+Pb and Au+Au collisions. The chemical freeze-out temperatures in p+p interactions are found to be larger than the corresponding temperatures in central nucleus-nucleus collisions.

  19. Surface chemical characteristics of coal fly ash particles after interaction with seawater under natural deep sea conditions

    International Nuclear Information System (INIS)

    The surface chemical characteristics of coal fly ash (CFA) before and after interaction with Mediterranean deep seawater was studied by X-ray photoelectron spectroscopy (XPS). Significantly lower values of Si, Ca, and S and higher values of Mg and Cl were found in the retrieved CFA as compared to fresh CFA. It is suggested that hydrolysis of the oxide matrixes results in an alkaline environment which rapidly leads to several chemical reactions. The two most important are (a) dissolution of the amorphous silicate and the calcium phases and (b) precipitation of Mg(OH)2-brucite. A depth profile of the retrieved CFA was measured by both line-shape analysis of the XPS spectra and by consecutive cycle of sputtering. The thickness of the brucite layer is estimated to be 1.3 nm

  20. Chemical immobilization of adult female Weddell seals with tiletamine and zolazepam: effects of age, condition and stage of lactation

    OpenAIRE

    Harcourt Robert G; Bradshaw Corey JA; Wheatley Kathryn E; Davis Lloyd S; Hindell Mark A

    2006-01-01

    Abstract Background Chemical immobilization of Weddell seals (Leptonychotes weddellii) has previously been, for the most part, problematic and this has been mainly attributed to the type of immobilizing agent used. In addition to individual sensitivity, physiological status may play an important role. We investigated the use of the intravenous administration of a 1:1 mixture of tiletamine and zolazepam (Telazol®) to immobilize adult females at different points during a physiologically demandi...

  1. Organic Food: A Comparative Study of the Effect of Tomato Cultivars and Cultivation Conditions on the Physico-Chemical Properties

    OpenAIRE

    Araujo, Jacqueline C; Samuel F. P. Telhado

    2015-01-01

    The objective of this review was to present an update of the currently managed studies on the characterization physical, chemical, and sensory analysis of several tomato cultivars. This review has indicated the importance of farming system and genotype on sensory and biochemical characteristics. It is necessary to use selected genotypes responding positively to organic farming in terms of sensory, biochemical characteristics and productivity aspects and to evaluate systems over more than one ...

  2. DEFINING SUCCESS IN PROJECTS

    Directory of Open Access Journals (Sweden)

    José Rodrigues de Farias Filho

    2011-05-01

    Full Text Available The Project Management Discipline has been widely used in the last years for companies around the world and these companies have been investing large amounts on surveys, training and consulting in order to get benefits for the organizations that need to create competitive advantage in the high competitive Market and to achieve their business strategy goals. Studies from the major world authors show many ways to define success at the organizations. In Brazil, the Benchmarking Study in GP from the PMI Chapters in 2009, show most studied companies don’t have a process do assess whether they are achieving the expected business goals with their investments in Project Management. This article goal is to demonstrate many ways to define success in project, which will facilitate the process to assess whether the companies are achieving these expected goals. The methodology used was a literature review, collecting publications, textbooks and documents from subject-matter-experts.

  3. Defining Legal Moralism

    DEFF Research Database (Denmark)

    Thaysen, Jens Damgaard

    2015-01-01

    This paper discusses how legal moralism should be defined. It is argued that legal moralism should be defined as the position that “For any X, it is always a pro tanto reason for justifiably imposing legal regulation on X that X is morally wrong (where “morally wrong” is not conceptually equivalent...... to “harmful”)”. Furthermore, a distinction between six types of legal moralism is made. The six types are grouped according to whether they are concerned with the enforcement of positive or critical morality, and whether they are concerned with criminalising, legally restricting, or refraining from...... legally protecting morally wrong behaviour. This is interesting because not all types of legal moralism are equally vulnerable to the different critiques of legal moralism that have been put forth. Indeed, I show that some interesting types of legal moralism have not been criticised at all....

  4. Defining talent management components

    OpenAIRE

    Golchin Shafieian

    2014-01-01

    In today's world of global trade, it can guarantee success and excellence of organizations against competitors is talented human resources in an organization, especially at the managerial level. But the challenges that organizations face include: attracting, evaluating, exploring, and developing and keeping talent. The main objective of this study is to define the components of talent management in the University of Chaloos, in order to provide a way to reduce the challenges and short comings...

  5. Defining local food

    DEFF Research Database (Denmark)

    Eriksen, Safania Normann

    2013-01-01

    Despite evolving local food research, there is no consistent definition of “local food.” Various understandings are utilized, which have resulted in a diverse landscape of meaning. The main purpose of this paper is to examine how researchers within the local food systems literature define local...... food, and how these definitions can be used as a starting point to identify a new taxonomy of local food based on three domains of proximity....

  6. Software Defined Networking

    OpenAIRE

    Roncero Hervás, Óscar

    2014-01-01

    Software Defined Networks (SDN) is a paradigm in which routing decisions are taken by a control layer. In contrast to conventional network structures, the control plane and forwarding plane are separated and communicate through standard protocols like OpenFlow. Historically, network management was based on a layered approach, each one isolated from the others. SDN proposes a radically different approach by bringing together the management of all these layers into a single controller. It is th...

  7. SDN : Software defined networks

    OpenAIRE

    Wiklund, Petter

    2014-01-01

    This report is a specialization in Software defined networking. SDN really comes to revolutionize the industry and it’s under constant development. But is the technology ready to be launched into operation yet? The report would initially involve a number of problems that today's network technology is facing. It then follows a deeper description of what this software-based networking technology really is and how it works. Further, the technique is being tested in a lab assignment, using a prog...

  8. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  9. Chemical and Physical Conditions in Molecular Cloud Core DC 000.4-19.5 (SL42) in Corona Australis

    OpenAIRE

    Hardegree-Ullman, E. E.; Harju, J.; Juvela, M.; Sipila, O.; Whittet, D. C. B.; Hotzel, S.

    2013-01-01

    Chemical reactions in starless molecular clouds are heavily dependent on interactions between gas phase material and solid phase dust and ices. We have observed the abundance and distribution of molecular gases in the cold, starless core DC 000.4-19.5 (SL42) in Corona Australis using data from the Swedish ESO Submillimeter Telescope. We present column density maps determined from measurements of C18O(J=2-1,1-0) and N2H+(J=1-0) emission features. Herschel data of the same region allow a direct...

  10. Crystal Engineering of an nbo Topology Metal-Organic Framework for Chemical Fixation of CO₂ under Ambient Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wen-Yang; Chen, Yao; Niu, Youhong; Williams, Kia; Cash, Lindsay; Perez, Pastor J.; Wojtas, Lukasz; Cai, Jianfeng; Chen, Yu-Sheng; Ma, Shengqian [UC; (USF)

    2015-02-20

    Crystal engineering of the nbo metal–organic framework (MOF) platform MOF-505 with a custom-designed azamacrocycle ligand (1,4,7,10-tetrazazcyclododecane-N,N',N'',N'''-tetra-p-methylbenzoic acid) leads to a high density of well-oriented Lewis active sites within the cuboctahedral cage in MMCF-2, [Cu₂(Cu-tactmb)(H₂O)₃(NO₃)₂]. This MOF demonstrates high catalytic activity for the chemical fixation of CO₂ into cyclic carbonates at room temperature under 1 atm pressure.

  11. Description of chemical and biological soil characteristics of two fields subjected to different agricultural management under mediterranean conditions

    Directory of Open Access Journals (Sweden)

    Salvatore M. Meli

    Full Text Available Several factors such as soil pollution and intensive agricultural management continuously damage the sustainability of agricultural production, with potentially adverse effects on soil quality. It is important to create applicable and valid soil quality indicators in order to both identify areas with potential productivity problems and monitor soil quality changes due to a range of perturbations. In this work we compared several chemical and biological variables between a Mediterranean soil characterized by intensive horticulture that has been irrigated for 20 years with moderately saline waters (IM and an adjacent soil, subjected to a sustainable agricultural production management and irrigated with plain water (SM. Soil sampling was repeated three times during a year in both sites. IM soil had lower pH, organic carbon and total nitrogen compared to SM soil at all sampling times, while its electrical conductivity was significantly higher at two sampling times only. Potentially mineralizable nitrogen pointed out significant differences only at the first sampling time, with lower levels in the SM soil. β-sitosterol, cholesterol and ergosterol varied significantly with sampling time and were influenced also by management. Statistical approach by Principal Component Analysis highlighted a contrast between two groups of soil variables: potentially mineralizable nitrogen and sterols mainly weighted on the first axis, while chemical properties, weighted on the second one. Moreover, the second axis separated the soil subjected to a sustainable agricultural production system from that subjected to intensive practice management, while the first axis separated the third sampling data from the first two.

  12. Adaptive plasticity of Laguncularia racemosa in response to different environmental conditions: integrating chemical and biological data by chemometrics.

    Science.gov (United States)

    da Souza, Iara; Bonomo, Marina Marques; Morozesk, Mariana; Rocha, Lívia Dorsch; Duarte, Ian Drumond; Furlan, Larissa Maria; Arrivabene, Hiulana Pereira; Monferrán, Magdalena Victoria; Matsumoto, Silvia Tamie; Milanez, Camilla Rozindo Dias; Wunderlin, Daniel Alberto; Fernandes, Marisa Narciso

    2014-04-01

    Mangroves are dynamic environments under constant influence of anthropic contaminants. The correlation between environmental contamination levels and possible changes in the morphology of plants, evaluated by multivariate statistics helps to highlight matching between these variables. This study aimed to evaluate the uptake and translocation of metals and metalloids in roots and leaves as well as the changes induced in both anatomy and histochemistry of roots of Laguncularia racemosa inhabiting two estuaries of Espírito Santo (Brazil) with different pollution degrees. The analysis of 14 elements in interstitial water, sediments and plants followed by multivariate statistics, allowed the differentiation of studied sites, showing good match between levels of elements in the environment with the corresponding in plants. L. racemosa showed variations in their root anatomy in different collection areas, with highest values of cortex/vascular cylinder ratio, periderm thickness and air gap area in Vitória Bay, the most polluted sampling area. These three parameters were also important to differentiate the mangrove areas by linear discriminant analysis. The development stage of aerenchyma in roots reflected the oxygen availability in the water, being found a negative correlation between these variables. The combined use of chemical and biological analyses responded quite well to different pollution scenarios, matching morphological responses to physical and chemical parameters, measured at different partitions within the estuary. Thus, L. racemosa can be confirmed as a reliable sentinel plant for biomonitoring of estuaries impacted by anthropic pollution. PMID:24445776

  13. Chemical characteristics of gel obtained from blend of colostrum and skim milk under different heat treatments conditions

    Directory of Open Access Journals (Sweden)

    Manikant Kumar

    2014-12-01

    Full Text Available Study was carried out to evaluate the chemical characteristics of colostrums and skim milk blended heat treated product. The present study was confined to standardization of colostrum harvested from 2nd milking of gir breed of cow based product in combination with skim milk, sugar and cardamom powder. The blends proportions of skim milk were @ 15, 30, 45% and addition of 8% cane sugar was found to impart the desired sweetness. Green cardamom powder was used as flavouring agent. These mixtures were kept in a water bath at 3 different temperatures viz. 60, 70 and 75⁰C for 30 minutes. Gelation occurs on heating to yield curd like products of different gel strength, which were cooled at room temperature and analysed for different chemical attributes like fat, protein, acidity etc. The results indicated that the fat, protein, acidity content decreased significantly (p˂ 0.01 however the moisture, total carbohydrate increased significantly (p˂0.01 but ash differed non significantly with increased in skim milk proportion in blend at different temperatures.

  14. Defining Business Network

    Directory of Open Access Journals (Sweden)

    Raffaele Trequattrini

    2012-02-01

    Full Text Available The purpose of the present scientific contribution is to investigate from the business economics standpoing the emerging phenomenon of company networks. In particular, through the analysis of the theory of networks will be proposed the principal categories of business networks, and even before this the concept of the network will be defined. The proposed research, qualitatively, represents the point of departure for the study of the network phenomenon in light of the current economic phase termed “economy of knowledge”. Moreover, the research questions are the following: From where does the theory of networks arise? Do company networks consider themselves equal to knowledge networks?

  15. Defining Business Network

    Directory of Open Access Journals (Sweden)

    Raffaele Trequattrini

    2012-02-01

    Full Text Available The purpose of the present scientific contribution is to investigate from the businesseconomics standpoing the emerging phenomenon of company networks. In particular,through the analysis of the theory of networks will be proposed the principal categories ofbusiness networks, and even before this the concept of the network will be defined. Theproposed research, qualitatively, represents the point of departure for the study of thenetwork phenomenon in light of the current economic phase termed “economy of knowledge”.Moreover, the research questions are the following: From where does the theory of networksarise? Do company networks consider themselves equal to knowledge networks?

  16. Body Condition Affects Blood Alkaloid and Monoterpene Kinetics and Voluntary Intake of Chemically-Defended Plants by Livestock

    Science.gov (United States)

    Poisonous plants are a substantial component of grazinglands worldwide. Higher losses to poisonous plants are often observed in times of drought or at high stocking rates. Increased incidences of fatal poisoning may occur because plants can be more toxic under these conditions or because limited acc...

  17. Defining talent management components

    Directory of Open Access Journals (Sweden)

    Golchin Shafieian

    2014-07-01

    Full Text Available In today's world of global trade, it can guarantee success and excellence of organizations against competitors is talented human resources in an organization, especially at the managerial level. But the challenges that organizations face include: attracting, evaluating, exploring, and developing and keeping talent. The main objective of this study is to define the components of talent management in the University of Chaloos, in order to provide a way to reduce the challenges and short comings and also to look for ways to improve employee performance is discussed. This study is based on data collected from all employees of the University of Chaloos in August 2013; through two questionnaires have been developed. The statistical population has been considered 407 persons in these universities and according the Morgan Table, 198 persons were selected as sample of among research society. More over, 28 questions are used for determining components of talent management. Finally, we concluded that the component of talent management have been properly defined in the Universities of Chaloos.

  18. Software-Defined Cluster

    Institute of Scientific and Technical Information of China (English)

    聂华; 杨晓君; 刘淘英

    2015-01-01

    The cluster architecture has played an important role in high-end computing for the past 20 years. With the advent of Internet services, big data, and cloud computing, traditional clusters face three challenges: 1) providing flexible system balance among computing, memory, and I/O capabilities;2) reducing resource pooling overheads;and 3) addressing low performance-power efficiency. This position paper proposes a software-defined cluster (SDC) architecture to deal with these challenges. The SDC architecture inherits two features of traditional cluster: its architecture is multicomputer and it has loosely-coupled interconnect. SDC provides two new mechanisms: global I/O space (GIO) and hardware-supported native access (HNA) to remote devices. Application software can define a virtual cluster best suited to its needs from resources pools provided by a physical cluster, and traditional cluster ecosystems need no modification. We also discuss a prototype design and implementation of a 32-processor cloud server utilizing the SDC architecture.

  19. Identification of improvised explosives residues using physical-chemical analytical methods under real conditions after an explosion

    Science.gov (United States)

    Kotrlý, Marek; Mareš, Bohumil; Turková, Ivana; Beroun, Ivo

    2016-05-01

    Within the analysis of cases relating to the use of explosives for crimes, we have experienced a shift from using industrial explosives towards substances made in amateur and illegal way. Availability of industrial explosives is increasingly limited to a narrow sphere of subjects with a relevant permission. Thus, on the part of perpetrators, terrorists, ever greater attention is paid to illegal production of explosives that are easily made from readily available raw materials. Another alarming fact is the availability of information found on the internet. Procedures of preparation are often very simple and do not require even a deeper professional knowledge. Explosive characteristics are not actually accessible for many of these substances (detonation velocity, sensitivity, working capacity, brisance, physical and chemical stability, etc.). Therefore, a project is being implemented, which on grounds of assessment of individual information available in literature and on the internet, aiming at choosing individual areas of potentially abusable substances (e.g. mixtures of nitric acid (98%) with organic substances, mixtures nitromethane and tetranitromethane with organic substances, mixtures of chlorates and perchlorates of alkali metals with organic substances, chemically individual compounds of organic base type of perchloric acid, azides, fulminates, acetylides, picrates, styphnates of heavy metals, etc.). It is directed towards preparation of these explosives also in non-stoichiometric mixtures, conducting test explosives, determination of explosive characteristics (if they are unknown) and analysis of both primary phases and post-blast residues through available analytical techniques, such as gas and liquid chromatography with mass detection, FTIR, micro-Raman spectrometry, electron microscopy with microanalysis and Raman microspectrometry directly in SEM chamber for analysis at the level of individual microparticles. The received characteristics will be used to

  20. CHEMICAL AND PHYSICAL CONDITIONS IN MOLECULAR CLOUD CORE DC 000.4-19.5 (SL42) IN CORONA AUSTRALIS

    Energy Technology Data Exchange (ETDEWEB)

    Hardegree-Ullman, E.; Whittet, D. C. B. [New York Center for Astrobiology and Department of Physics, Applied Physics, and Astronomy, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, NY 12180 (United States); Harju, J. [Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Vaeisaelaentie 20, FI-21500, Piikkioe (Finland); Juvela, M.; Sipilae, O. [Department of Physics, P.O. Box 64, FI-00014, University of Helsinki (Finland); Hotzel, S., E-mail: hardee@rpi.edu [Observatory, FI-00014, University of Helsinki (Finland)

    2013-01-20

    Chemical reactions in starless molecular clouds are heavily dependent on interactions between gas phase material and solid phase dust and ices. We have observed the abundance and distribution of molecular gases in the cold, starless core DC 000.4-19.5 (SL42) in Corona Australis using data from the Swedish ESO Submillimeter Telescope. We present column density maps determined from measurements of C{sup 18}O (J = 2-1, 1-0) and N{sub 2}H{sup +} (J = 1-0) emission features. Herschel data of the same region allow a direct comparison to the dust component of the cloud core and provide evidence for gas phase depletion of CO at the highest extinctions. The dust color temperature in the core calculated from Herschel maps ranges from roughly 10.7 to 14.0 K. This range agrees with the previous determinations from Infrared Space Observatory and Planck observations. The column density profile of the core can be fitted with a Plummer-like density distribution approaching n(r) {approx} r {sup -2} at large distances. The core structure deviates clearly from a critical Bonnor-Ebert sphere. Instead, the core appears to be gravitationally bound and to lack thermal and turbulent support against the pressure of the surrounding low-density material: it may therefore be in the process of slow contraction. We test two chemical models and find that a steady-state depletion model agrees with the observed C{sup 18}O column density profile and the observed N(C{sup 18}O) versus A{sub V} relationship.

  1. Impact of Flight Enthalpy, Fuel Simulant, and Chemical Reactions on the Mixing Characteristics of Several Injectors at Hypervelocity Flow Conditions

    Science.gov (United States)

    Drozda, Tomasz G.; Baurle, Robert A.; Drummond, J. Philip

    2016-01-01

    The high total temperatures or total enthalpies required to duplicate the high-speed flight conditions in ground experiments often place stringent requirements on the material selection and cooling needs for the test articles and intrusive flow diagnostic equipment. Furthermore, for internal flows, these conditions often complicate the use of nonintrusive diagnostics that need optical access to the test section and interior portions of the flowpath. Because of the technical challenges and increased costs associated with experimentation at high values of total enthalpy, an attempt is often made to reduce it. This is the case for the Enhanced Injection and Mixing Project (EIMP) currently underway in the Arc-Heated Scramjet Test Facility at the NASA Langley Research Center. The EIMP aims to investigate supersonic combustion ramjet (scramjet) fuel injection and mixing physics, improve the understanding of underlying physical processes, and develop enhancement strategies and functional relationships between mixing performance and losses relevant to flight Mach numbers greater than 8. The experiments will consider a "direct-connect" approach and utilize a Mach 6 nozzle to simulate the combustor entrance flow of a scramjet engine. However, while the value of the Mach number is matched to that expected at the combustor entrance in flight, the maximum value of the total enthalpy for these experiments is limited by the thermal-structural limits of the uncooled experimental hardware. Furthermore, the fuel simulant is helium, not hydrogen. The use of "cold" flows and non-reacting mixtures of fuel simulants for mixing experiments is not new and has been extensively utilized as a screening technique for scramjet fuel injectors. In this study, Reynolds-averaged simulations are utilized (RAS) to systematically verify the implicit assumptions used by the EIMP. This is accomplished by first performing RAS of mixing for two injector configurations at planned nominal experimental

  2. Evaluation of regional climate - air quality simulations over Europe for the period 1996-2006 with emphasis on tropospheric ozone: The impact of chemical boundary conditions

    Science.gov (United States)

    Akritidis, D.; Zanis, P.; Katragkou, E.; Tegoulias, I.; Poupkou, A.; Markakis, K.; Karacostas, Th.; Pytharoulis, I.

    2012-04-01

    A modeling system based on the air quality model CAMx driven off-line by the regional climate model RegCM3 is used for assessing the impact of lateral boundary conditions on tropospheric ozone over Europe for the period 1996-2006. The RegCM3 and CAMx simulations were performed on a 50 km x 50 km grid over Europe with RegCM3 driven by NCEP reanalysis fields. Average monthly concentration values obtained from the global chemistry climate model ECHAM5-MOZ were used as chemical boundary conditions for the CAMx simulations. The present period (1996-2006) was simulated two times. The first run (clean) was forced from constant lateral chemical boundary conditions and constant emissions based on the EMEP emissions of the year 1996. The second simulation (run1) was based on ECHAM5-MOZ chemical boundary conditions and emissions fixed for the year 1996. In order to evaluate the ability of the RegCM3/CAMx modeling system, simulated ozone concentrations are compared against near surface ozone measurements from the EMEP network. Since many of the stations of the EMEP network were not operating continuously during the time period of our study (1996-2006), we have used in the evaluation analysis only those stations that fulfill the criteria of 75% data availability for near surface ozone, choosing 87 stations from 23 European countries. Various statistical metrics are used for the model evaluation, including correlation coefficient (R), normalized standard deviation (NSD) and modified normalized mean bias (MNMB). The different lateral boundary conditions forcing resulted in changes of near surface ozone concentrations and variability. Using lateral boundary conditions obtained from the global chemistry climate model ECHAM5-MOZ (run1), the RegCM3/CAMx modeling system is capturing in a much better way the ozone monthly variability than using constant lateral boundary conditions (clean), especially for stations of northern and northwestern Europe. Concerning the correlation between

  3. Distribution of small dispersive coal dust particles and absorbed radioactive chemical elements in conditions of forced acoustic resonance in iodine air filter at nuclear power plant

    CERN Document Server

    Ledenyov, Oleg P

    2013-01-01

    The physical features of distribution of the small dispersive coal dust particles and the adsorbed radioactive chemical elements and their isotopes in the absorber with the granular filtering medium with the cylindrical coal granules were researched in the case of the intensive air dust aerosol stream flow through the iodine air filter (IAF). It was shown that, at the certain aerodynamic conditions in the IAF, the generation of the acoustic oscillations is possible. It was found that the acoustic oscillations generation results in an appearance of the standing acoustic waves of the air pressure (density) in the IAF. In the case of the intensive blow of the air dust aerosol, it was demonstrated that the standing acoustic waves have some strong influences on both: 1) the dynamics of small dispersive coal dust particles movement and their accumulation in the IAF; 2) the oversaturation of the cylindrical coal granules by the adsorbed radioactive chemical elements and their isotopes in the regions, where the antin...

  4. Photocatalytic TiO2 thin films for air cleaning : Effect of facet orientation, chemical functionalization, and reaction conditions

    OpenAIRE

    Stefanov, Bozhidar

    2015-01-01

    Poor indoor air quality is a source of adverse health effects. TiO2 coatings deposited on well-illuminated surfaces, such as window panes, can be used to fully mineralize indoor air pollutants by photocatalysis. In such applications it is important to ensure stable photocatalytic activity for a wide range of operating conditions, such as relative humidity and temperature, and to avoid deactivation of the catalyst. In this thesis photocatalytic removal of the indoor-pollutant acetaldehyde (CH3...

  5. PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

    OpenAIRE

    Carolina M. Furtado; Aline dos Santos Stolz; Fernanda L. Pinto; Angela B. D. Moura; Fernando Dal Pont Morisso; Ana Paula Pitarelo; Luiz Pereira Ramos; Carin von Mühlen; Izabel C. Riegel-Vidotti

    2015-01-01

    Acacia mearnsii de Wild (black wattle) is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with...

  6. A framework incorporating the impact of exposure scenarios and application conditions on risk assessment of chemicals applied to skin

    OpenAIRE

    Dancik, Yuri; Troutman, John A; Jaworska, Joanna

    2013-01-01

    Purpose 1. To develop a framework for exposure calculation via the dermal route to meet the needs of 21st century toxicity testing and refine current approaches; 2. To demonstrate the impact of exposure scenario and application conditions on the plasma concentration following dermal exposure. Method A workflow connecting a dynamic skin penetration model with a generic whole-body physiologically-based pharmacokinetic (PBPK) model was developed. The impact of modifying exposure scenarios and ap...

  7. On Defining Mass

    Science.gov (United States)

    Hecht, Eugene

    2011-01-01

    Though central to any pedagogical development of physics, the concept of mass is still not well understood. Properly defining mass has proven to be far more daunting than contemporary textbooks would have us believe. And yet today the origin of mass is one of the most aggressively pursued areas of research in all of physics. Much of the excitement surrounding the Large Hadron Collider at CERN is associated with discovering the mechanism responsible for the masses of the elementary particles. This paper will first briefly examine the leading definitions, pointing out their shortcomings. Then, utilizing relativity theory, it will propose—for consideration by the community of physicists—a conceptual definition of mass predicated on the more fundamental concept of energy, more fundamental in that everything that has mass has energy, yet not everything that has energy has mass.

  8. Implementing Software Defined Radio

    CERN Document Server

    Grayver, Eugene

    2013-01-01

    Software Defined Radio makes wireless communications easier, more efficient, and more reliable. This book bridges the gap between academic research and practical implementation. When beginning a project, practicing engineers, technical managers, and graduate students can save countless hours by considering the concepts presented in these pages. The author covers the myriad options and trade-offs available when selecting an appropriate hardware architecture. As demonstrated here, the choice between hardware- and software-centric architecture can mean the difference between meeting an aggressive schedule and bogging down in endless design iterations. Because of the author’s experience overseeing dozens of failed and successful developments, he is able to present many real-life examples. Some of the key concepts covered are: Choosing the right architecture for the market – laboratory, military, or commercial Hardware platforms – FPGAs, GPPs, specialized and hybrid devices Standardization efforts to ens...

  9. Effect of spectra recording conditions on the example of chemical shifts calculation in CMR spectra of 1-pentylbenzoylformate

    OpenAIRE

    Mizyuk, Volodymyr; Shibanov, Volodymyr

    2011-01-01

    The concept of "compatible" and "incompatible" CMR spectra has been introduced. Application of compatibility increments (IC) allows to calculate the chemical shifts of C and C3 atoms of pentyloxyl fragment in 1-pentylbenzoylformate with a sufficiently good accuracy. Введено поняття "сумісних " і "несумісних " ЯМР спектрів. Застосування "інкрементів узгодження " дало можливість з достатньою точністю розрахувати хімічні зсуви атомів С2 і С пентилоксильного фрагменту в 1-пентилбензоїлформіаті....

  10. Laboratory study of chemical speciation of mercury in lake sediment and water under aerobic and anaerobic conditions

    International Nuclear Information System (INIS)

    Chemical speciation and partitioning of radiolabeled HgCl2 were studied in model aquatic systems consisting of undisturbed eutrophic lake sediment and water in plastic cylinders. The cylinders were either gradually made anaerobic by a gentle flow of N2-CO2 or kept aerobic by air flow. The proportion of methylated 203Hg was significantly higher, in both water and sediment, in the anaerobic systems than in the aerobic systems. The composition and total concentration of fatty acids originating from bacterial phospholipids, as well as the concentration of vitamin B12, including related cobalamins, were similar in sediments from the anaerobic and aerobic systems. Bacterial cell numbers were, on average, 3.6 times higher in the anaerobic water columns than in the aerobic ones. Volatilization of 203Hg occurred in all systems except in an autoclaved control and was of similar magnitudes in the anaerobic and aerobic systems. Incorporation of 203Hg into the sediment was significantly faster in the aerobic systems than in the anaerobic systems. These results suggest that episodes of anoxia in bottom waters and sediment cause an increase in net mercury methylation and, hence, an increase in bioavailable mercury

  11. Effects of chemical composition and test conditions on the dynamic tensile response of Zr-based metallic glasses

    Science.gov (United States)

    Wang, F.; Laws, K. J.; Trujillo, C. P.; Brown, A. D.; Cerreta, E. K.; Hazell, P. J.; Quadir, M. Z.; Ferry, M.; Escobedo, J. P.

    2015-06-01

    The effects of impact velocity and temperature on the dynamic mechanical behavior of two bulk metallic glasses (BMG) with slightly different elemental compositions (Zr55Cu30Ni5Al30 and Zr46Cu38Ag8Al38) have been investigated. Bullet-shaped samples were accelerated by a gas gun to speeds in the 400 ~ 600m/s range and tested at room temperature and 250 °C. The specimens impacted a steel extrusion die which subjected them to high strains at high strain-rates. The extruded samples were subsequently soft recovered by using low density foams. The deformed specimens were examined by optical and electron microscopy, x-ray diffraction and hardness measurements. The characterization results aided to assess the effect of chemical composition on the microstructural evolution, i.e. phase changes or crystallization, which might influence the ductility on the nominally brittle amorphous BMGs. The most significant results from this study will be presented. School of Engineering and Information Technology, UNSW Canberra.

  12. Influence of variable chemical conditions on EDTA-enhanced transport of metal ions in mildly acidic groundwater

    Science.gov (United States)

    Kent, D.B.; Davis, J.A.; Joye, J.L.; Curtis, G.P.

    2008-01-01

    Adsorption of Ni and Pb on aquifer sediments from Cape Cod, Massachusetts, USA increased with increasing pH and metal-ion concentration. Adsorption could be described quantitatively using a semi-mechanistic surface complexation model (SCM), in which adsorption is described using chemical reactions between metal ions and adsorption sites. Equilibrium reactive transport simulations incorporating the SCMs, formation of metal-ion-EDTA complexes, and either Fe(III)-oxyhydroxide solubility or Zn desorption from sediments identified important factors responsible for trends observed during transport experiments conducted with EDTA complexes of Ni, Zn, and Pb in the Cape Cod aquifer. Dissociation of Pb-EDTA by Fe(III) is more favorable than Ni-EDTA because of differences in Ni- and Pb-adsorption to the sediments. Dissociation of Ni-EDTA becomes more favorable with decreasing Ni-EDTA concentration and decreasing pH. In contrast to Ni, Pb-EDTA can be dissociated by Zn desorbed from the aquifer sediments. Variability in adsorbed Zn concentrations has a large impact on Pb-EDTA dissociation.

  13. Assay of antioxidant potential of two Aspergillus isolates by different methods under various physio-chemical conditions

    Directory of Open Access Journals (Sweden)

    Daljit Singh Arora

    2010-10-01

    Full Text Available The objective of this work was to screen fungi isolated from soil of different areas of Punjab, India for antioxidant activity by dot blot assay and around 45% of fungal isolates demonstrated antioxidant potential. Two selected strains of Aspergillus spp (Aspergillus PR78 and Aspergillus PR66 showing quantitatively best antioxidant activity by DPPH assay were further tested for their reducing power, ferrous ion and nitric oxide ion scavenging activity, FRAP assay and total phenolic content. Different physio-chemical parameters were optimized for enhancement of the activity. This revealed stationary culture grown for 10 days at 25ºC at pH 7 to be the best for antioxidant activity. Sucrose in the medium as carbon source resulted in highest antioxidant activity. Sodium nitrate, yeast extract, and peptone were good sources of nitrogen but sodium nitrate was the best among these. The extraction of the broth culture filtrates with different solvents revealed ethyl acetate extract to possess the best antioxidant activity. The activity as expressed by ethyl acetate extract of Aspergillus PR78 was equally effective as that of commonly used antioxidant standard, ascorbic acid.

  14. Production of Italian Dry Salami: Effect of Starter Culture and Chemical Acidulation on Staphylococcal Growth in Salami Under Commercial Manufacturing Conditions

    OpenAIRE

    Metaxopoulos, J.; Genigeorgis, C.; Fanelli, M. J.; Franti, C.; Cosma, E.

    1981-01-01

    The effect of starter culture and chemical acidulation on the growth and enterotoxigenesis of Staphylococcus aureus strain S-6 in Italian dry salami under commercial manufacturing conditions was studied. The experimental design included two levels of S. aureus (104 and 105/g), three levels of starter culture (0, 105, and 106/g), three levels of initial pH (pH0) (6.1, 5.5, and 4.8), two manufacturing plants, and three replications. S. aureus growth in the salami was affected significantly (P <...

  15. Volume reduction on all particle size of the contaminated soil. Continuous processing technology of attrition, chemical wash under an ambient temperature and pressure condition and magnetic separation

    International Nuclear Information System (INIS)

    An examination was conducted in order to establish a practical purification system that could largely reduce the storage volume of radioactive waste in the Intermediate Storage Facility. The examination consists of a 3-step washing treatment of contaminated soil, which includes “Milling Washing” of removed contaminated soil, chemical extraction of fine soil fraction resulted from the “Milling Washing” under an ambient temperature and pressure condition, and magnetic separation of cesium from the extracted solution. As a result of the examination, we succeeded in development of a safe system with low initial cost and running cost. (author)

  16. PYROLIGNEOUS LIQUOR PRODUCED FROM ACACIA MEARNSII DE WILD WOOD UNDER CONTROLLED CONDITIONS AS A RENEWABLE SOURCE OF CHEMICALS

    Directory of Open Access Journals (Sweden)

    Carolina M. Furtado

    2015-09-01

    Full Text Available Acacia mearnsii de Wild (black wattle is one of the most important trees planted in Southern Brazil for tannin extraction and charcoal production. The pyrolysis of the black wattle wood used for obtaining charcoal is performed in brick ovens, with the gas fraction being sent directly into the environment. The present study examines the condensable compounds present in the liquor produced from black wattle wood at different thermal degradation conditions, using gas chromatography coupled with mass spectrometry (GC/MS. Branches of black wattle were thermally degraded at controlled ambient and temperature conditions. Overall, a higher variety of compounds were obtained under atmospheric air pressure than under synthetic air pressure. Most of the tentatively identified compounds, such as carboxylic acids, phenols, aldehydes, and low molecular mass lignin fragments, such as guayacol, syringol, and eugenol, were products of lignin thermoconversion. Substituted aromatic compounds, such as vanillin, ethyl vanillin, and 2-methoxy-4-propeny-phenol, were also identified. At temperatures above 200 ºC, furan, 2-acetylfuran, methyl-2-furoate, and furfural, amongst others, were identified as polysaccharide derivatives from cellulose and hemicellulose depolymerization. This study evidences the need for adequate management of the condensable by-products of charcoal production, both for economic reasons and for controlling their potential environmental impact.

  17. Roller milling fractionation of green gram (Vigna radiata): optimization of milling conditions and chemical characterization of millstreams.

    Science.gov (United States)

    Sakhare, Suresh D; Inamdar, Aashitosh A; Gaikwad, Shwetha B; D, Indrani; G, Vekateswara Rao

    2014-12-01

    In the view of recent growing interest in utilization of grain fractions as food ingredient, present investigation was carried out to evaluate the roller milling potential of green gram. The effect of conditioning moistures on green gram roller milling were studied. The results showed decrease in flour yield from 85.56 to 58.74 % with increase in conditioning moisture from 10 to 16 %. Higher yield of flour was observed from the first (C1), second (C2) and third (C3) reduction passages; whereas, the first (B1), second (B2) and third (B3) break passages produced less flour. The distribution of protein, dietary fiber, ash and fat in different flour streams and by-products from roller milled fractions of green gram showed wide variation. The protein content increased with increasing numbers of breaks and reductions in the flour streams. The highest protein content of 30.16 % was found in bran duster flour and lowest (11.32 %) in fine seed coat. The protein content of break streams was found lower than reduction streams. The dietary fiber content of coarse seed coat was highest (71.17 %) followed by the fine seed coat (57.22 %). The microstructure studies of milled fractions of green gram showed more deformed and damaged starch granules in reduction flour streams than break flour streams. PMID:25477653

  18. Optimisation of chemical purification conditions for direct application of solid metal salt coagulants: Treatment of peatland-derived diffuse runoff

    Institute of Scientific and Technical Information of China (English)

    Elisangela Heiderscheidt; Jaakko Saukkoriipi; Anna-Kaisa Ronkanen; Bjφrn Klφve

    2013-01-01

    The drainage of peatland areas for peat extraction,agriculture or bioenergy requires affordable,simple and reliable treatment methods that can purify waters rich in particulates and dissolved organic carbon.This work focused on the optimisation of chemical purification process for the direct dosage of solid metal salt coagulants.It investigated process requirements of solid coagulants and the influence of water quality,temperature and process parameters on their performance.This is the first attempt to provide information on specific process requirements of solid coagulants.Three solid inorganic coagulants were evaluated:aluminium sulphate,ferric sulphate and ferric aluminium sulphate.Pre-dissolved aluminium and ferric sulphate were also tested with the objective of identifying the effects of in-line coagulant dissolution on purification performance.It was determined that the pre-dissolution of the coagulants had a significant effect on coagulant performance and process requirements.Highest purification levels achieved by solid coagulants,even at 30% higher dosages,were generally lower (5%-30%) than those achieved by pre-dissolved coagulants.Furthermore,the mixing requirements of coagulants pre-dissolved prior to addition differed substantially from those of solid coagulants.The pH of the water samples being purified had a major influence on coagulant dosage and purification efficiency.Ferric sulphate (70 mg/L) was found to be the best performing solid coagulant achieving the following load removals:suspended solids (59%-88%),total organic carbon (56%-62%),total phosphorus (87%-90%),phosphate phosphorus (85%-92%) and total nitrogen (33%-44%).The results show that the use of solid coagulants is a viable option for the treatment of peatland-derived runoff water if solid coagulant-specific process requirements,such as mixing and settling time,are considered.

  19. Defining the Anthropocene

    Science.gov (United States)

    Lewis, Simon; Maslin, Mark

    2016-04-01

    Time is divided by geologists according to marked shifts in Earth's state. Recent global environmental changes suggest that Earth may have entered a new human-dominated geological epoch, the Anthropocene. Should the Anthropocene - the idea that human activity is a force acting upon the Earth system in ways that mean that Earth will be altered for millions of years - be defined as a geological time-unit at the level of an Epoch? Here we appraise the data to assess such claims, first in terms of changes to the Earth system, with particular focus on very long-lived impacts, as Epochs typically last millions of years. Can Earth really be said to be in transition from one state to another? Secondly, we then consider the formal criteria used to define geological time-units and move forward through time examining whether currently available evidence passes typical geological time-unit evidence thresholds. We suggest two time periods likely fit the criteria (1) the aftermath of the interlinking of the Old and New Worlds, which moved species across continents and ocean basins worldwide, a geologically unprecedented and permanent change, which is also the globally synchronous coolest part of the Little Ice Age (in Earth system terms), and the beginning of global trade and a new socio-economic "world system" (in historical terms), marked as a golden spike by a temporary drop in atmospheric CO2, centred on 1610 CE; and (2) the aftermath of the Second World War, when many global environmental changes accelerated and novel long-lived materials were increasingly manufactured, known as the Great Acceleration (in Earth system terms) and the beginning of the Cold War (in historical terms), marked as a golden spike by the peak in radionuclide fallout in 1964. We finish by noting that the Anthropocene debate is politically loaded, thus transparency in the presentation of evidence is essential if a formal definition of the Anthropocene is to avoid becoming a debate about bias. The

  20. Phisico-Chemical Response of Seven Irrigated and Non-Irrigated Apple Fruit Varieties to Different Storage Conditions

    Directory of Open Access Journals (Sweden)

    Otilia Micu

    2015-11-01

    Full Text Available Apple fruits are among the most consumed fruits in the world, an increased demand of good quality fruits being observed also during the winter and spring period, therefore the storage performance of apple fruits is a very important aspect for a good crop valorization. Fruit flesh firmness, fruit sugar content and its weight loss during storage are very important factors in assessing the quality of fruits, as well as their storage performance. The irrigation regime and the storage conditions are also very important aspects to fruit growers, as they can influence the yield, the quality and also the price for fresh fruits. Therefore, the interactions of these factors are studied, in order to observe the effects they have on the evolution of the three parameters for fruit quality, during the storage period.

  1. A wind tunnel for measuring volatilization and biomineralization of environmental chemicals from the soil/plant system under field-like conditions

    International Nuclear Information System (INIS)

    Lysimeters can provide detailed information about the long-term behaviour of pesticides under field-like conditions, exploiting the advantages of radioactive labelled substances. A significant drawback of lysimetry has been the inability to provide complete material balance due to volatile losses of chemicals and their degradates. A wind tunnel, including new analytic methods and application sprayer, has been designed and developed to measure the volatile losses of 14C-labelled chemicals after application by methods comparable to agricultural practice. The wind-tunnel combines the advantages of laboratory facilities (use of radioisotopes) and field studies (field-like climate) and thus is a link between model chamber experiments in the laboratory and genuine field tests, and permits transfer of data to the field situation. Two wind-tunnel experiments were carried out with the herbicide diflufenican (DFF) and the insecticide parathion methyl (PM). In both experiments, insignificant amounts of 14CO2 were released. By the end of the experiment, nearly all of the DFF (96.7%) was in the 0-5 cm soil layer, whereas the majority of PM had volatilized (73.3%). Significant quantities of radioactivity (21.9%) also become fixed in nonextractable plant material following PM application. Results demonstrate that the new system can contribute significantly to detailed understanding of the volatilization and degradation behaviour of environmental chemicals

  2. Decree No85-968 of 27 August 1986 amending Article R.233-83 of the Labour Code and defining the health and safety conditions to be met by gamma industrial radiography equipment

    International Nuclear Information System (INIS)

    This Decree, amending Article R 233-83 of the Labour Code, applies to gamma-ray industrial radiography equipment whether mobile or fixed. It contains specific technical conditions concerning the equipment, in particular, safety devices located at the entry and exit points of the source's shield. The equipment must carry a notice mentioning''Radioactive''prepared by the constructor or the importer of the source, which explains the conditions for handling, setting-up, use and maintenance of the source, including the frequency of revisions. The Decree entered into force on 1 June 1986. (NEA)

  3. Defining political community

    Directory of Open Access Journals (Sweden)

    Sladeček Michal M.

    2002-01-01

    Full Text Available This paper considers the concept of political community, its constitution and value. The starting point is that the concept of community is not sufficiently recognized in modern political theories, as well as in contemporary liberal theory. In the last two decades communitarian and republican political theory attempted to revitalize this notion. The first part of the paper elaborates on the polemics between these three theoretical orientations. The concluding part examines the possibilities and prospect for stable political community in conditions of pluralism of particular social communities and ethnocultural heterogeneity.

  4. Summary of the work performed during the CRP on chemical durability and performance assessment under simulated repository conditions

    International Nuclear Information System (INIS)

    The safe disposal of the high-level wastes arising from reprocessing of the spent fuel comprises, as a first step, immobilizing them in waste forms with high leaching resistance to an aqueous medium. Currently, the most developed process on an industrial scale is the incorporation of the high level wastes into a glass matrix. This is done by melting technology at temperatures from 1400 deg to 1500 deg K. One of the main reasons for selecting the glass form material is because of its durability and stability to aqueous corrosion, thermal loading and radiation damage. With the intention of evaluating other alternatives, more advantageous processes or materials, a research and development program studying the sintering process applied to materials from several sources and with different compositions has been carried out since 1984 at the Nuclear Materials Group, Centro Atomico Bariloche. One of the advantages of the glass sintering process, relative to glass melting, is the lower temperature required (approximately 1050 deg K). This implies less demanding conditions for the equipment and a diminution of the evaporation of volatile compounds of some radionuclides (i.e., Ru, Cs, Mo and Te). Furthermore, problems originating from crucible erosion that would lead to uncontrollable variations in the product composition are avoided. Finally, the macrosegregation phenomena occurring in molten glass are minimized. At our laboratories we studied the cold pressing and sintering method and the hot pressing method, to obtain glass samples containing simulated high-level wastes. The later method was also developed up to semi-industrial scale. In the field of behavior of the waste forms under simulated repository conditions, our group performed work in the frame of the IAEA/CNEA-CAB Research Contract No. 6745. The corresponding results were presented at various IAEA Coordination Meetings and in the Progress and final Reports of each year . Those works covered aspects related to the

  5. Influence of recoil-implanted and thermally released iodine on I-SCC of Zircaloy-4 in PCI-conditions: chemical aspects

    International Nuclear Information System (INIS)

    The pellet cladding interaction (PCI) phenomenon can lead to cladding failure by iodine induced stress corrosion cracking (I-SCC) during power transients. In these situations, the aggressive species is present as both, recoil implanted iodine in the cladding, and gaseous iodine thermally released in the gap. The aim of this work is to determine the respective roles of implanted and gaseous iodine in the SCC phenomenon. Two types of SCC tests have thus been performed. In the first one, zirconium and iodine recoil implanted tensile test specimens were used, with implantation profiles typical of those existing in a cladding under PCI conditions either on the dose or on the induced damage standpoint. These tests have shown that recoil implanted iodine has no chemical effect on the development of the SCC cracks. The second type of tests was performed on reference tensile test specimens at 350 C with iodine released either, in oxygen containing atmospheres or, at increasing temperatures. The iodine efficiency for cracks initiation was found to be stronger when no oxygen is available for repassivation and when iodine is released at higher temperature. These two conditions being fulfilled during PCI loading, since no gaseous oxygen is available in the fuel-to-clad gap, and since iodine is released through the pellet radical cracks at high temperature, thermally released iodine can be considered as the chemical active species responsible for SCC. (orig.)

  6. Experimental device for chemical osmosis measurement on natural clay-rock samples maintained at in situ conditions: implications for formation pressure interpretations.

    Science.gov (United States)

    Rousseau-Gueutin, Pauline; de Greef, Vincent; Gonçalvès, Julio; Violette, Sophie; Chanchole, Serge

    2009-09-01

    In order to characterize the so-called coupled processes occurring in compacted clay rocks, the coupling coefficients must be identified. For this purpose, an original device which allows such measurement for undisturbed (natural) samples in their in situ conditions was developed. The present experimental device minimizes the fluid leaks improving the accuracy of the coupling parameter determination. Three chemical osmotic tests were performed on a cylindrical sample of Callovo-Oxfordian argilite. Room temperature variations during the chemical osmosis experiments required the implementation of temperature effects in the numerical model used for the interpretations. These variations offered the opportunity of an alternative method to estimate the compressibility of the fluid in the circuit connected to a measurement chamber located in the center of the sample. An osmotic efficiency of almost 0.2 for a concentration of 0.094 mol L(-1) is obtained for the Callovo-Oxfordian argilite. This value would explain only some part (approximately 0.10-0.15 MPa) of the overpressures (0.5-0.6 MPa) relative to the surrounding reservoirs measured in this formation. Others processes, such as thermo-osmosis, hydrodynamic boundary condition changes due to climate variations or creep behavior of the shale, could explain the remainder of the overpressures. PMID:19527907

  7. Ion mobility spectrometry versus classical physico-chemical analysis for assessing the shelf life of extra virgin olive oil according to container type and storage conditions.

    Science.gov (United States)

    Garrido-Delgado, Rocío; Dobao-Prieto, M Mar; Arce, Lourdes; Aguilar, Joaquín; Cumplido, José L; Valcárcel, Miguel

    2015-03-01

    An experimental study was conducted to assess the stability of a single-variety (Arbequina) extra virgin olive oil (EVOO) as a function of container type and storage conditions over a period of 11 months. EVOO quality was assessed by using ion mobility spectrometry (IMS), which provides increased simplicity, expeditiousness, and relative economy. The results were compared with the ones obtained by using the official method based on classical physico-chemical analysis. Bag-in-box, metal, dark glass, clear glass, and polyethylene terephthalate containers holding EVOO were opened on a periodic basis for sampling to simulate domestic use; in parallel, other containers were kept closed until analysis to simulate the storage conditions on market shelves. The results of the physico-chemical and instrumental analyses led to similar conclusions. Thus, samples packaged in bag-in-box containers preserved oil quality for 11 months, better than other container types. The HS-GC-IMS results confirm that 2-heptenal and 1-penten-3-one are two accurate markers of EVOO quality. PMID:25645180

  8. Method of conditional moments (MCM) for the Chemical Master Equation: a unified framework for the method of moments and hybrid stochastic-deterministic models.

    Science.gov (United States)

    Hasenauer, J; Wolf, V; Kazeroonian, A; Theis, F J

    2014-09-01

    The time-evolution of continuous-time discrete-state biochemical processes is governed by the Chemical Master Equation (CME), which describes the probability of the molecular counts of each chemical species. As the corresponding number of discrete states is, for most processes, large, a direct numerical simulation of the CME is in general infeasible. In this paper we introduce the method of conditional moments (MCM), a novel approximation method for the solution of the CME. The MCM employs a discrete stochastic description for low-copy number species and a moment-based description for medium/high-copy number species. The moments of the medium/high-copy number species are conditioned on the state of the low abundance species, which allows us to capture complex correlation structures arising, e.g., for multi-attractor and oscillatory systems. We prove that the MCM provides a generalization of previous approximations of the CME based on hybrid modeling and moment-based methods. Furthermore, it improves upon these existing methods, as we illustrate using a model for the dynamics of stochastic single-gene expression. This application example shows that due to the more general structure, the MCM allows for the approximation of multi-modal distributions. PMID:23918091

  9. Tailor-made surfactants for optimized chemical EOR. Meeting oil reservoir conditions by applied knowledge of structure-performance relationship in extended surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Trahan, G.; Sorensen, W. [Sasol North America Inc., Westlake, LA (United States); Jakobs-Sauter, B. [Sasol Germany GmbH (Germany)

    2013-08-01

    Formulating the surfactant package for chemical EOR is a time consuming and expensive process - the formulation needs to fit the specific reservoir conditions (like oil type, temperature, salinity, etc.) to give optimum performance and the number of formulation variables is virtually endless. This paper studies the impact of surfactant structure on EOR formulation ability and performance and how to adjust the structure of the surfactant molecule to meet a specific reservoir's needs. Data from salinity phase boundary studies of alcohol propoxy sulfates illustrate how changes in alcohol structure as well as in propylene oxide level can shift optimum salinity and temperature to the desired range in a given model oil. From these data the impact of individual structural units was evaluated. Application of the HLD model (Hydrophilic-Lipophilic Deviation) shows how to extrapolate from the known data set to actual reservoir conditions. This is illustrated by studies on crude oil samples. Additional tests study how effective the selected surfactants perform. The HLD concept proves to be a valuable tool to select and tailor surfactants to individual reservoir needs, thus simplifying the surfactant screening process for EOR formulations by pre-selection of suitable structures and ultimately reducing cost and effort on the way to the most effective chemical EOR package. (orig.)

  10. Defining an emerging disease.

    Science.gov (United States)

    Moutou, F; Pastoret, P-P

    2015-04-01

    Defining an emerging disease is not straightforward, as there are several different types of disease emergence. For example, there can be a 'real' emergence of a brand new disease, such as the emergence of bovine spongiform encephalopathy in the 1980s, or a geographic emergence in an area not previously affected, such as the emergence of bluetongue in northern Europe in 2006. In addition, disease can emerge in species formerly not considered affected, e.g. the emergence of bovine tuberculosis in wildlife species since 2000 in France. There can also be an unexpected increase of disease incidence in a known area and a known species, or there may simply be an increase in our knowledge or awareness of a particular disease. What all these emerging diseases have in common is that human activity frequently has a role to play in their emergence. For example, bovine spongiform encephalopathy very probably emerged as a result of changes in the manufacturing of meat-and-bone meal, bluetongue was able to spread to cooler climes as a result of uncontrolled trade in animals, and a relaxation of screening and surveillance for bovine tuberculosis enabled the disease to re-emerge in areas that had been able to drastically reduce the number of cases. Globalisation and population growth will continue to affect the epidemiology of diseases in years to come and ecosystems will continue to evolve. Furthermore, new technologies such as metagenomics and high-throughput sequencing are identifying new microorganisms all the time. Change is the one constant, and diseases will continue to emerge, and we must consider the causes and different types of emergence as we deal with these diseases in the future. PMID:26470448

  11. Effect of chemical composition on physical properties of non-magnetic high manganese steel and its processing condition

    International Nuclear Information System (INIS)

    For the purpose of lowering the thermal expansion coefficient of high manganese austenitic steel, the effects of carbon and manganese content on the thermal expansion coefficient from 0 to 1000C were investigated. The permeability after cold working and electrical resistivity were measured in these steels. These physical properties were also investigated after addition of various alloying element such as Si, Cu, Ni, Cr, Mo, Co, and Al in 0.25%C-25%Mn (or 21%Mn) based steel. The decrease of carbon content and the increase of manganese content markedly reduced the thermal expansion coefficient. The addition of ferrite forming elements did not result in increase of permeability, but electrical resistivity was markedly increased with addition of Si or Mo in 0.25%C-25%Mn steel. Particularly, the mechanism controlling the thermal expansion coefficient of high manganese austenitic steel is discussed by making reference to existing theories. Hot ductility and strengthening due to controlled rolling in high manganese austenitic steel were studied to establish the optimum processing condition. (author)

  12. Specific Language Impairment, Nonverbal IQ, Attention-Deficit/Hyperactivity Disorder, Autism Spectrum Disorder, Cochlear Implants, Bilingualism, and Dialectal Variants: Defining the Boundaries, Clarifying Clinical Conditions, and Sorting out Causes

    Science.gov (United States)

    Rice, Mabel L.

    2016-01-01

    Purpose: The purpose of this research forum article is to provide an overview of a collection of invited articles on the topic "specific language impairment (SLI) in children with concomitant health conditions or nonmainstream language backgrounds." Topics include SLI, attention-deficit/hyperactivity disorder, autism spectrum disorder,…

  13. Dynamics-based selective 2D {sup 1}H/{sup 1}H chemical shift correlation spectroscopy under ultrafast MAS conditions

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Rongchun; Ramamoorthy, Ayyalusamy, E-mail: ramamoor@umich.edu [Biophysics and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055 (United States)

    2015-05-28

    Dynamics plays important roles in determining the physical, chemical, and functional properties of a variety of chemical and biological materials. However, a material (such as a polymer) generally has mobile and rigid regions in order to have high strength and toughness at the same time. Therefore, it is difficult to measure the role of mobile phase without being affected by the rigid components. Herein, we propose a highly sensitive solid-state NMR approach that utilizes a dipolar-coupling based filter (composed of 12 equally spaced 90° RF pulses) to selectively measure the correlation of {sup 1}H chemical shifts from the mobile regions of a material. It is interesting to find that the rotor-synchronized dipolar filter strength decreases with increasing inter-pulse delay between the 90° pulses, whereas the dipolar filter strength increases with increasing inter-pulse delay under static conditions. In this study, we also demonstrate the unique advantages of proton-detection under ultrafast magic-angle-spinning conditions to enhance the spectral resolution and sensitivity for studies on small molecules as well as multi-phase polymers. Our results further demonstrate the use of finite-pulse radio-frequency driven recoupling pulse sequence to efficiently recouple weak proton-proton dipolar couplings in the dynamic regions of a molecule and to facilitate the fast acquisition of {sup 1}H/{sup 1}H correlation spectrum compared to the traditional 2D NOESY (Nuclear Overhauser effect spectroscopy) experiment. We believe that the proposed approach is beneficial to study mobile components in multi-phase systems, such as block copolymers, polymer blends, nanocomposites, heterogeneous amyloid mixture of oligomers and fibers, and other materials.

  14. Electrochemical and quantum chemical assessment of two organic compounds from pyridine derivatives as corrosion inhibitors for mild steel in HCl solution under stagnant condition and hydrodynamic flow

    International Nuclear Information System (INIS)

    Highlights: •Pyridine-2-thiol, P2T, and 2-Pyridyl disulfide, 2PD, are good inhibitors. •P2T and 2PD reveal 98% efficiency in 200 mg/L concentration at stagnant condition. •Langmuir isotherm shows both physisorption and chemisorption types for inhibitors. •Mild steel corrosion rate decreases with rising rotation speed in blank solution. •Hydrodynamic flow has a destructive effect on inhibitors performance. -- Abstract: In this study, the inhibitive performance of two pyridine derivatives as corrosion inhibitors for mild steel was examined under stagnant condition and hydrodynamic flow in HCl solution at 25 °C. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques were employed. To explore the inhibitors adsorption mechanism, Langmuir isotherm and quantum chemical studies were used. The results of electrochemical measurements show that the inhibitor concentration has a positive effect on its efficiency while for hydrodynamic condition, it is vice versa. Corrosion attack morphologies were observed at stagnant and hydrodynamic conditions to verify qualitatively the results obtained by electrochemical methods

  15. Biological aspects of the DM28C clone of Trypanosoma cruzi after metacylogenesis in chemically defined media Aspectos biológicos do clone Dm 28c de Trypanosoma cruzi após metaciclogênese em meio quimicamente definido

    Directory of Open Access Journals (Sweden)

    Victor T. Contreras

    1988-03-01

    Full Text Available The biological characterization of the Trypanosoma cruzi clone Dm 28c in terms of its growth in LIT medium, cell-cycle, infectivity to mice and interaction with professional and non-professional phagocytic cells shows that it behaves as a bona fide T. cruzi representant. The biological properties of this myotropic clone do not change according to the origin of the trypomastigote forms (i. e., from triatomines, infected mice, cell-culture or from the chemically defined TAUP and TAU3AAG media. In addition Dm 28c metacyclic trypomastigotes from TAU3AAG medium display a high infectivity level to fibroblasts and muscle cells. Experiments on binding of cationized ferritin to trypomastigotes surface show the existence of cap-like structures of ferritin in regions near the kinetoplast. However the nature and role of these anionic sites remain to be determined. The results indicate that metacyclic trypomastigotes from Dm 28c clone obtained under chemically defined conditions reproduce the biological behaviour of T. cruzi, rendering this system very suitable for the study of cell-parasite interactions and for the isolation of trypanosome relevant macromolecules.A caracterização biológica do clone Dm 28c de Trypanosoma cruzi em termos do seu crescimento em meio LIT, ciclo celular, infectividade para camundongos e interação com células fagocíticas profissionais e não-profissionais, mostra que o mesmo comporta-se como um fiel representante da espécie T. cruzi. As propriedades biológicas deste clone miotrópico não mudam de acordo com a proveniência das formas tripomastigotas (i. e., de triatomíneos, de camundongos infectados, de cultura celular ou dos meios quimicamente definidos TAUP e TAU3AAG. Ainda mais, formas tripomastigotas metacíclicas do clone Dm 28c derivado do meio TAU3AAG apresentam um alto grau de infectividade para fibroblastos e células de músculo. Experimentos de ligação de ferritina cationizada à superfície de

  16. Chemical durability of vitrified high-level waste and spent fuel under simulated repository conditions of a Boom Clay formation

    International Nuclear Information System (INIS)

    The Belgian programme is considering both the closed and open fuel cycle options. In the closed cycle, HLW glasses from the former Eurochemic reprocessing plant and from the French R7T7 plants are studied. R and D is focused on the interaction with the Boom Clay disposal host and potential near field environments. In surface laboratory testing we developed new set-ups to investigate various coupled processes: (1) combined glass leaching/Si diffusion in clay, (2) diffusion/sorption/precipitation of Si in clay, (3) effect of the presaturation of clay with Si, and (4) the mobile concentrations of e.g. Np, Tc, Se in clay slurries after leaching from glass. In the CORALUS in situ test, we installed four tubes in the underground laboratory (SCK-CEN site), and retrieved two of them after an interaction time of ∼1 year (90 deg. C) and ∼3 years (30 deg C). The R and D on the geological disposal of spent fuel in Boom Clay is focused on two major issues: (1) study the effect of α-activity on the dissolution of α-doped UO2 (simulating spent fuel ages between 150 and 90000 years), and (2) study the influence of Boom Clay and potential backfill materials (apatite, cement, sand) on the α-doped UO2 dissolution rate. Different experimental set-ups have been elaborated. Flowthrough tests in clay water and static tests in clay slurries were carried out in reducing conditions. We report the main results obtained on both HLW glass and doped UO2. Both HLW glass and UO2 show a similar evolution of the dissolution behaviour with time in the clay containing media. After an initial relatively fast dissolution characterized by sorption onto the clay, a much lower dissolution rate is observed. For both waste forms this results in expected lifetimes during geological disposal of 105 years or more. (author)

  17. Effect of nontronite smectite clay on the chemical evolution of several organic molecules under simulated martian surface ultraviolet radiation conditions.

    Science.gov (United States)

    Poch, Olivier; Jaber, Maguy; Stalport, Fabien; Nowak, Sophie; Georgelin, Thomas; Lambert, Jean-François; Szopa, Cyril; Coll, Patrice

    2015-03-01

    Most of the phyllosilicates detected at the surface of Mars today are probably remnants of ancient environments that sustained long-term bodies of liquid water at the surface or subsurface and were possibly favorable for the emergence of life. Consequently, phyllosilicates have become the main mineral target in the search for organics on Mars. But are phyllosilicates efficient at preserving organic molecules under current environmental conditions at the surface of Mars? We monitored the qualitative and quantitative evolutions of glycine, urea, and adenine in interaction with the Fe(3+)-smectite clay nontronite, one of the most abundant phyllosilicates present at the surface of Mars, under simulated martian surface ultraviolet light (190-400 nm), mean temperature (218 ± 2 K), and pressure (6 ± 1 mbar) in a laboratory simulation setup. We tested organic-rich samples that were representative of the evaporation of a small, warm pond of liquid water containing a high concentration of organics. For each molecule, we observed how the nontronite influences its quantum efficiency of photodecomposition and the nature of its solid evolution products. The results reveal a pronounced photoprotective effect of nontronite on the evolution of glycine and adenine; their efficiencies of photodecomposition were reduced by a factor of 5 when mixed at a concentration of 2.6 × 10(-2) mol of molecules per gram of nontronite. Moreover, when the amount of nontronite in the sample of glycine was increased by a factor of 2, the gain of photoprotection was multiplied by a factor of 5. This indicates that the photoprotection provided by the nontronite is not a purely mechanical shielding effect but is also due to stabilizing interactions. No new evolution product was firmly identified, but the results obtained with urea suggest a particular reactivity in the presence of nontronite, leading to an increase of its dissociation rate. PMID:25734356

  18. Microstructure, physical and chemical properties of nanostructured (Ti–Hf–Zr–V–Nb)N coatings under different deposition conditions

    Energy Technology Data Exchange (ETDEWEB)

    Pogrebnjak, A.D.; Yakushchenko, I.V. [Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy (Ukraine); Bagdasaryan, A.A., E-mail: artemsumdu@ukr.net [Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy (Ukraine); Bondar, O.V. [Sumy State University, 2, Rymsky Korsakov Str., 40007 Sumy (Ukraine); Krause-Rehberg, R. [Martin-Luther-University Halle-Wittenberg, Halle (Germany); Abadias, G.; Chartier, P. [Institut P' , University of Poitiers, Chasseneuil-Futuroscope (France); Oyoshi, K.; Takeda, Y. [National Institute for Material Science, Tsukuba (Japan); Beresnev, V.M. [Kharkiv National University, 21, Svobody Sq., 4, 61022 Kharkiv (Ukraine); Sobol, O.V. [National Technical University, Kharkiv Polytechnic Institute, Kharkiv (Ukraine)

    2014-10-15

    High-entropy alloy and nitride coatings (TiHfZrVNb)N were prepared by the cathodic-arc-vapor-deposition method under various deposition conditions. The composition, crystal structure, strain-stress state, profiles of defects and atoms in-depth and at surfaces of the (TiHfZrVNb)N coatings were characterized by EDS and SEM analysis, X-ray diffraction with “α-sin{sup 2}ψ” method of measurements and slow positron beam. The oxidation behavior of nitride films after annealing at 600 °C temperature was studied. The results indicate that nitride coatings show the face-centered cubic crystal structure. The redistributions of elements and defects, their arrangement (segregation) due to the thermally stimulated diffusion and termination of the spinodal segregation near the interfaces, around the grains and subgrains were found. The peak hardness and modulus of the nitride films were 44.3 and 384 GPa, respectively. The tribological properties of the (TiHfZrVNb)N coatings against AISI 1045 were evaluated by a ball-on-disc tribometer with a 3.0 N applied load. - Highlights: • (Ti–Hf–Zr–V–Nb)N coatings produced by CAVD exhibit enhanced strength. • The influence of deposition parameters on the defect structure in the coating was discussed. • Partial relaxation of compressive stress is observed after thermal annealing at 600 °C. • Coatings deposited on the steel substrate improve its tribological performance.

  19. Analysis of chemical abundances in planetary nebulae with [WC] central stars. I. Line intensities and physical conditions

    Science.gov (United States)

    García-Rojas, J.; Peña, M.; Morisset, C.; Mesa-Delgado, A.; Ruiz, M. T.

    2012-02-01

    Context. Planetary nebulae (PNe) around Wolf-Rayet [WR] central stars ([WR]PNe) constitute a particular photoionized nebula class that represents about 10% of the PNe with classified central stars. Aims: We analyse deep high-resolution spectrophotometric data of 12 [WR] PNe. This sample of [WR]PNe represents the most extensive analysed so far, at such high spectral resolution. We aim to select the optimal physical conditions in the nebulae to be used in ionic abundance calculations that will be presented in a forthcoming paper. Methods: We acquired spectra at Las Campanas Observatory with the 6.5-m telescope and the Magellan Inamori Kyocera (MIKE) spectrograph, covering a wavelength range from 3350 Å to 9400 Å. The spectra were exposed deep enough to detect, with signal-to-noise ratio higher than three, the weak optical recombination lines (ORLs) of O ii, C ii, and other species. We detect and identify about 2980 emission lines, which, to date, is the most complete set of spectrophotometric data published for this type of objects. From our deep data, numerous diagnostic line ratios for Te and ne are determined from collisionally excited lines (CELs), ORLs, and continuum measurements (H i Paschen continuum in particular). Results: Densities are closely described by the average of all determined values for objects with ne behaviour of both temperatures agrees with the predictions of the temperature fluctuations paradigm, owing to the large errors in Te(H i). We do not find any evidence of low-temperature, high-density clumps in our [WR]PNe from the analysis of faint O ii and N ii plasma diagnostics, although uncertainties dominate the observed line ratios in most objects. The behaviour of Te([O iii])/Te([N ii]), which is smaller for high ionization degrees, can be reproduced by a set of combined matter-bounded and radiation-bounded models, although, for the smallest temperature ratios, a too high metallicity seem to be required. Based on data obtained at Las

  20. Chemical constraints governing the origin of metabolism: the thermodynamic landscape of carbon group transformations under mild aqueous conditions

    Science.gov (United States)

    Weber, Arthur L.

    2002-01-01

    The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies (deltaG) were estimated for four types of reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed (1) that generally when carbon-carbon bond cleavage involves groups from different functional group classes (i.e., carboxylic acids, carbonyl groups, alcohols, and hydrocarbons), the transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) that the energy of carbon-carbon bond transformation is primarily determined by the functional group class of the group that changes oxidation state in the reaction (i.e., the functional group class of the group that donates the shared electron-pair during cleavage, or that accepts the incipient shared electron-pair during synthesis). In contrast, the energy of hydrogen transfer between carbon groups is determined by the functional group class of both the hydrogen-donor group and the hydrogen-acceptor group. From these and other observations we concluded that the chemistry involved in the origin of metabolism (and to a lesser degree modern metabolism) was strongly constrained by (1) the limited redox-based transformation energy of organic substrates that is readily dissipated in a few energetically favorable irreversible reactions; (2) the energy dominance of a few transformation half-reactions that determines whether carbon-carbon bond transformation (cleavage or synthesis) is energetically favorable (deltaG +3.5 kcal/mol); and (3) the dependence of carbon group transformation energy on the

  1. PRODUCTION UNDER CONTROLLED CONDITIONS OF “CASU MARZU” CHEESE: EFFECT OF THE Piophila Casei COLONIZATION ON MICROBIAL AND CHEMICAL COMPOSITION OF THE CHEESES

    Directory of Open Access Journals (Sweden)

    M Coinu

    2013-02-01

    Full Text Available The aim of the present study was to evaluate the effect of the Piophila casei colonization under controlled conditions on “casu marzu”, a typical Sardinian sheep milk cheese. Three batches of two different kind of cheese (PO, holed paste and PC, firm paste were produced in duplicate (test and control. Test cheeses were exposed to the Piophila casei colonization in a conditioned store room, while control cheeses were suitably protected. All the samples were analyzed at 0, 10, 30, 60 and 90 days from the production. The pH and aw, the chemical composition and the microbiological parameters (food safety and process hygiene criteria were determined. The colonization was unhomogeneous between the batches: PO cheeses were more easily colonized and showed more intense proteolysis and lipolysis respect to PC cheeses. The microbiological parameters were strongly affected by the experimental process conditions. The authors discuss about the opportunity of a controlled production of “casu marzu” and the implications to the health of consumers.

  2. Optimized chemical composition, working and heat treatment condition for resistance to irradiation assisted stress corrosion cracking of cold worked 316 and high-chromium austenitic stainless steel

    International Nuclear Information System (INIS)

    The authors have reported that the primary water stress corrosion cracking (PWSCC) in baffle former bolts made of austenitic stainless steels for PWR after long-term operation is caused by irradiation-induced grain boundary segregation. The resistance to PWSCC of simulated austenitic stainless steels whose chemical compositions are simulated to the grain boundary chemical composition of 316 stainless steel after irradiation increased with decrease of the silicon content, increases of the chromium content, and precipitation of M23C6 carbides at the grain boundaries. In order to develop resistance to irradiation assisted stress corrosion cracking in austenitic stainless steels, optimized chemical compositions and heat treatment conditions for 316CW and high-chromium austenitic stainless steels for PWR baffle former bolts were investigated. For 316CW stainless steel, ultra-low-impurities and high-chromium content are beneficial. About 20% cold working before aging and after solution treatment has also been recommended to recover sensitization and make M23C6 carbides coherent with the matrix at the grain boundaries. Heating at 700 to 725degC for 20 to 50 h was selected as a suitable aging procedure. Cold working of 5 to 10% after aging produced the required mechanical properties. The optimized composition of the high-chromium austenitic stainless steel contents 30% chromium, 30% nickel, and ultra-low impurity levels. This composition also reduces the difference between its thermal expansion coefficient and that of 304 stainless steel for baffle plates. Aging at 700 to 725degC for longer than 40 h and cold working of 10 to 15% after aging were selected to meet mechanical property specifications. (author)

  3. Estimating pesticide sampling rates by the polar organic chemical integrative sampler (POCIS) in the presence of natural organic matter and varying hydrodynamic conditions

    Science.gov (United States)

    Charlestra, Lucner; Amirbahman, Aria; Courtemanch, David L.; Alvarez, David A.; Patterson, Howard

    2012-01-01

    The polar organic chemical integrative sampler (POCIS) was calibrated to monitor pesticides in water under controlled laboratory conditions. The effect of natural organic matter (NOM) on the sampling rates (Rs) was evaluated in microcosms containing -1 of total organic carbon (TOC). The effect of hydrodynamics was studied by comparing Rs values measured in stirred (SBE) and quiescent (QBE) batch experiments and a flow-through system (FTS). The level of NOM in the water used in these experiments had no effect on the magnitude of the pesticide sampling rates (p > 0.05). However, flow velocity and turbulence significantly increased the sampling rates of the pesticides in the FTS and SBE compared to the QBE (p pesticide concentrations in water from POCIS deployed in stagnant and turbulent environmental systems without correction for NOM.

  4. Chemically Synthesized Glycosides of Hydroxylated Flavylium Ions as Suitable Models of Anthocyanins: Binding to Iron Ions and Human Serum Albumin, Antioxidant Activity in Model Gastric Conditions

    Directory of Open Access Journals (Sweden)

    Sheiraz Al Bittar

    2014-12-01

    Full Text Available Polyhydroxylated flavylium ions, such as 3',4',7-trihydroxyflavylium chloride (P1 and its more water-soluble 7-O-β-d-glucopyranoside (P2, are readily accessible by chemical synthesis and suitable models of natural anthocyanins in terms of color and species distribution in aqueous solution. Owing to their catechol B-ring, they rapidly bind FeIII, weakly interact with FeII and promote its autoxidation to FeIII. Both pigments inhibit heme-induced lipid peroxidation in mildly acidic conditions (a model of postprandial oxidative stress in the stomach, the colorless (chalcone forms being more potent than the colored forms. Finally, P1 and P2 are moderate ligands of human serum albumin (HSA, their likely carrier in the blood circulation, with chalcones having a higher affinity for HSA than the corresponding colored forms.

  5. Analysis Of Convective Plane Stagnation Point Chemically Reactive Mhd Flow Past A Vertical Porous Plate With A Convective Boundary Condition In The Presence Of A Uniform Magnetic Field.

    Directory of Open Access Journals (Sweden)

    Adeniyan, A.,

    2013-09-01

    Full Text Available The numerical investigation of a stagnation point boundary layer flow , mass and heat transfer of a steady two dimensional , incompressible , viscous electrically conducting, chemically reacting laminar fluid over a vertical convectively heated , electrically neutral flat plate exposed to a transverse uniform magnetic field has been carried out to examine the influence of the simultaneous presence of the effects of a convective boundary condition, chemical reaction, heat transfer and suction or injection. The governing coupled partial differential equations have been reduced to a set of coupled nonlinear ordinary differential equations by means of the similarity transformation , which has been solved using the classical fourth order Runge-Kutta method alongside with a shooting technique. The computational results have been presented by means of the table and discussed graphically. It has been observed that pertinent and invaluable engineering parameters such as the Skin-friction coefficient, the plate temperature distribution, the velocity , temperature and concentration profiles are appreciably influenced by flow parameters such as the magnetic field, convective heat parameters , Prandtl number, Sherwood number, Nusselt number, etc .

  6. Chemical response of Picea glehnii seed-epiphytic Penicillium species to Pythium vexans under in vitro competitive conditions for mycelial growth.

    Science.gov (United States)

    Yamaji, Keiko; Hashidoko, Yasuyuki; Fukushi, Yukiharu; Tahara, Satoshi

    2005-04-01

    The potential protection of Picea glehnii seedlings from damping-off by seed-epiphytic Penicillium species was investigated. We studied the chemical response of seed-epiphytic Penicillium species (Pen. cyaneum, Pen. damascenum, and Pen. implicatum) to Pythium vexans, a damping-off fungus, in vitro. Penicillium species were cultured singly or cocultured with Pyt. vexans for 14 or 18 d, and mycelial growth, pH of culture filtrate, antifungal activity of the culture filtrate against Pyt. vexans, and the amount of antifungal compound produced by each Penicillium species, were examined. The filtrate of both the single culture of Penicillium and the coculture of Penicillium and Pyt. vexans showed antifungal activity against Pyt. vexans. In a coculture with Pyt. vexans, Pen. cyaneum produced an antifungal compound (patulin) as in the single culture. Pen. damascenum cocultured with Pyt. vexans produced an antifungal compound (citrinin), as it did in the single culture and in larger amounts on day 10. Pen. implicatum produced two antifungal compounds, frequentin and palitantin, and the ratio of frequentin (with higher antifungal activity than palitantin) to palitantin was higher in the coculture with Pyt. vexans than in the single culture. Our results indicate that these Penicillium species have the ability to produce antifungal compounds and to keep anti-fungal activity under competitive condition with Pyt. vexans. The chemical response of these Penicillium species to Pyt. vexans may contribute to protect P. glehnii seedlings from damage by Pyt. vexans. PMID:16124252

  7. MHD Heat and Mass Transfer of Chemical Reaction Fluid Flow over a Moving Vertical Plate in Presence of Heat Source with Convective Surface Boundary Condition

    Directory of Open Access Journals (Sweden)

    B. R. Rout

    2013-01-01

    Full Text Available This paper aims to investigate the influence of chemical reaction and the combined effects of internal heat generation and a convective boundary condition on the laminar boundary layer MHD heat and mass transfer flow over a moving vertical flat plate. The lower surface of the plate is in contact with a hot fluid while the stream of cold fluid flows over the upper surface with heat source and chemical reaction. The basic equations governing the flow, heat transfer, and concentration are reduced to a set of ordinary differential equations by using appropriate transformation for variables and solved numerically by Runge-Kutta fourth-order integration scheme in association with shooting method. The effects of physical parameters on the velocity, temperature, and concentration profiles are illustrated graphically. A table recording the values of skin friction, heat transfer, and mass transfer at the plate is also presented. The discussion focuses on the physical interpretation of the results as well as their comparison with previous studies which shows good agreement as a special case of the problem.

  8. Development of the investigation and evaluation method for geochemical condition of underground. Part 4. Chemical weathering and influence of concrete on tunnel walls

    International Nuclear Information System (INIS)

    For the safety assessment of the low level radioactive waste disposal site, it is necessary to evaluate the long term geochemical conditions of natural barrier around facilities. In this study, geochemical properties of sedimentary rock at the test cavern of the Rokkasho site were investigated. The oxidation of the tunnel wall that passed eight years after the excavation reached from the rock surface to about 1.5-3cm. The amount of sulfide has decreased in this zone. The oxidized depth depends on the saturation condition by the influence of ventilation. The rate of oxidation of the bedrock can be presumed of the chemical composition change according to the oxidation of the rock, the environment of the tunnel, and the coefficient of permeability of the rock. Chemical properties of bed rock surfacing to the concrete were slightly changed during five years contact. The void water of bed rock in 20cm depth from concrete contacted surface showed diffusion effect of Ca from concrete with raising pH up to about 10. There was wide difference of pH and concentration of those alkaline ions between the pore water of concrete and void water of bed rock, the former showed much high pH and concentration of alkaline ions. Though there were the diffusion of alkaline ions, the consumption of OH- that is the factor of raising pH, was occurred at the concrete contacted surface area of the bed rock with forming calcium silicate compound at surface of volcanic grass in the bed rock. During the formation of C-S-H product in the space of bed rock, the space was reduced. There are needs to estimate the oxidation of the rock, the stability of secondary product, i.e. C-S-H, and the mechanical property of altered bed rock for the long term evaluation of natural barrier at the radioactive waste disposal site. (author)

  9. Defining Life: Synthesis and Conclusions

    Science.gov (United States)

    Gayon, Jean

    2010-04-01

    The first part of the paper offers philosophical landmarks on the general issue of defining life. §1 defends that the recognition of “life” has always been and remains primarily an intuitive process, for the scientist as for the layperson. However we should not expect, then, to be able to draw a definition from this original experience, because our cognitive apparatus has not been primarily designed for this. §2 is about definitions in general. Two kinds of definition should be carefully distinguished: lexical definitions (based upon current uses of a word), and stipulative or legislative definitions, which deliberately assign a meaning to a word, for the purpose of clarifying scientific or philosophical arguments. The present volume provides examples of these two kinds of definitions. §3 examines three traditional philosophical definitions of life, all of which have been elaborated prior to the emergence of biology as a specific scientific discipline: life as animation (Aristotle), life as mechanism, and life as organization (Kant). All three concepts constitute a common heritage that structures in depth a good deal of our cultural intuitions and vocabulary any time we try to think about “life”. The present volume offers examples of these three concepts in contemporary scientific discourse. The second part of the paper proposes a synthesis of the major debates developed in this volume. Three major questions have been discussed. A first issue (§4) is whether we should define life or not, and why. Most authors are skeptical about the possibility of defining life in a strong way, although all admit that criteria are useful in contexts such as exobiology, artificial life and the origins of life. §5 examines the possible kinds of definitions of life presented in the volume. Those authors who have explicitly defended that a definition of life is needed, can be classified into two categories. The first category (or standard view) refers to two conditions

  10. An approach to quantifying the chemical conditions necessary to form a magnetite layer on steels in lead and lead–bismuth eutectic

    Energy Technology Data Exchange (ETDEWEB)

    Qvist, Staffan, E-mail: staffan.qvist@physics.uu.se

    2014-11-15

    Highlights: • Conditions for corrosion protection of steels in lead-based coolants were quantified. • Maximum allowable temperatures spans of such loops are defined. • The concept of a “protective triangle” for corrosion protection is introduced. - Abstract: In this study, the parameter space where a magnetite (Fe{sub 3}O{sub 4}) film forms on the surfaces of steels exposed to non-isothermal oxygen-controlled Pb and LBE coolant loops while avoiding PbO contamination has been quantified by a consistent set of 6 equations. These equations provide both the allowable temperature range of operation as well as the range of oxygen concentrations that must be maintained within the loop. The equations allow for a set of margins on the oxygen and iron concentrations in the system. Given a value for the maximum temperature within the loop, the minimum allowable temperature can be calculated and vice versa. The “protective triangle” concept was introduced to visualize the principles of the conditions promoting corrosion protection, and how these are affected by changing temperatures, concentrations and applied margins.

  11. Introduction to Galactic Chemical Evolution

    CERN Document Server

    Matteucci, Francesca

    2016-01-01

    In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models of galactic chemical evolution will be described. They include: initial conditions, star formation history, stellar nucleosynthesis and gas flows in and out of galaxies. Then some simple analytical models and their solutions will be discussed together with the main criticisms associated to them. The yield per stellar generation will be defined and the hypothesis of instantaneous recycling approximation will be critically discussed. Detailed numerical models of chemical evolution of galaxies of different morphological type, able to follow the time evolution of the abundances of single elements, will be discussed and their predictions will be compared to observational data. The comparisons will include stellar abundances as well as interstellar medium ones, measured in galax...

  12. Chemical Changes in Pore Water Composition due to CO2 Injection Under In-Situ P-T Condition of the Altmark Gas Reservoir, Germany

    Science.gov (United States)

    Huq, F.; Nowak, M.; Haderlein, S.; Grathwohl, P.

    2012-12-01

    CO2 storage in depleted gas reservoir combined with enhanced gas recovery may be an economically feasible option to mitigate global warming. The Altmark gas field, located in the western part of the Northeast German Basin, is being considered as a potential candidate for this purpose. Under reservoir conditions (50 bars and 125°C), the CO2 saturated water causes dissolution and subsequent precipitation of minerals of the surrounding rock matrix. Therefore, the main objective of the current study was to investigate the chemical changes in fluid composition due to dissolution/precipitation of minerals under controlled laboratory conditions. A dry sandstone plug from the Altmark reservoir was mounted in a newly designed autoclave system and flushed by a pre-equilibrated mixture of water saturated with CO2 at a constant flow rate of 0.25 cm/h for 12 days at reservoir conditions. Fluid samples were taken at regular intervals for major and trace element analysis and pH was measured simultaneously in the partially de-gassed samples. Fluid analysis showed an increased concentration of Na, K and Cl ions at the beginning indicating early leaching of halite and sylvite which initially inhibited the dissolution of alkali feldspars. Feldspar dissolution occurred later and slower indicated by lower concentrations of Na and K reflecting the lower solubility and slow dissolution kinetics of feldspar. Dissolution of anhydrite was predominantly observed from the increased concentration of Ca and SO4 at earlier time periods. However, the Ca/SO4 molar ratio (>1) indicated the concurrent dissolution of both calcite and anhydrite. The presence of carbonates buffered the pH until day 6. Moreover, the mobilization of Mn, Mg, Ba and Fe might be derived from carbonate impurities. Thermodynamic calculations of mineral saturation indices enabled an evaluation of the CO2-water-rock interactions during the experiment and highlighted the dissolution of the Ca-bearing minerals in the studied

  13. EVOLUTION OF CHEMICAL CONDITIONS AND ESTIMATED SOLUBILITY CONTROLS ON RADIONUCLIDES IN THE RESIDUAL WASTE LAYER DURING POST-CLOSURE AGING OF HIGH-LEVEL WASTE TANKS

    Energy Technology Data Exchange (ETDEWEB)

    Denham, M.; Millings, M.

    2012-08-28

    This document provides information specific to H-Area waste tanks that enables a flow and transport model with limited chemical capabilities to account for varying waste release from the tanks through time. The basis for varying waste release is solubilities of radionuclides that change as pore fluids passing through the waste change in composition. Pore fluid compositions in various stages were generated by simulations of tank grout degradation. The first part of the document describes simulations of the degradation of the reducing grout in post-closure tanks. These simulations assume flow is predominantly through a water saturated porous medium. The infiltrating fluid that reacts with the grout is assumed to be fluid that has passed through the closure cap and into the tank. The results are three stages of degradation referred to as Reduced Region II, Oxidized Region II, and Oxidized Region III. A reaction path model was used so that the transitions between each stage are noted by numbers of pore volumes of infiltrating fluid reacted. The number of pore volumes to each transition can then be converted to time within a flow and transport model. The bottoms of some tanks in H-Area are below the water table requiring a different conceptual model for grout degradation. For these simulations the reacting fluid was assumed to be 10% infiltrate through the closure cap and 90% groundwater. These simulations produce an additional four pore fluid compositions referred to as Conditions A through D and were intended to simulate varying degrees of groundwater influence. The most probable degradation path for the submerged tanks is Condition C to Condition D to Oxidized Region III and eventually to Condition A. Solubilities for Condition A are estimated in the text for use in sensitivity analyses if needed. However, the grout degradation simulations did not include sufficient pore volumes of infiltrating fluid for the grout to evolve to Condition A. Solubility controls for use

  14. Effects of lactic acid bacteria with bacteriocinogenic potential on the fermentation profile and chemical composition of alfalfa silage in tropical conditions.

    Science.gov (United States)

    Silva, V P; Pereira, O G; Leandro, E S; Da Silva, T C; Ribeiro, K G; Mantovani, H C; Santos, S A

    2016-03-01

    The fermentation profile, chemical composition, and microbial populations of alfalfa silages treated with microbial inoculants (MI) at different fermentation periods (T) were evaluated in tropical conditions. A 4×6 factorial arrangement was used in a randomized design with 3 replicates. Fresh alfalfa was treated with (1) no treatment (CTRL), (2) commercial inoculant (CIN), (3) Pediococcus acidilactici (strain 10.6, S1), and (4) Pediococcus pentosaceus (strain 6.16, S2). An inoculant application rate of 10(6) cfu/g of fresh forage was used. The fermentation periods were 1, 3, 7, 14, 28, and 56 d. Alfalfa was harvested 82 d after sowing at the early flowering stage, chopped into 1.5-cm particle size, and ensiled in 25 × 35 cm vacuum-sealed plastic bags. The numbers of lactic acid bacteria, enterobacteria, mold, and yeast in alfalfa before ensiling were 5.42, 5.58, 4.82, and 4.8 log cfu/g, respectively. Silage chemical composition was evaluated only at 56 d. All parameters were affected by the interaction MI × T, except the concentrations of lactic and propionic acids. Alfalfa silage treated with S1 or S2 had lower pH values than CTRL from the first day until 28 d. However, the inoculants resulted in similar pH after 56 d, and these values were lower than the CTRL. The highest concentration of lactic acid was observed in the silage treated with S1 and S2 at 7 and 14 d of ensiling. The concentration of acetic acid was lower in the silages treated with S1 and S2 than the CTRL and CIN at 3 and 28 d of fermentation. There was no effect of MI or MI × T interaction on the microbial populations. However, the number of enterobacteria decreased over the fermentation period until 14 d and increased slightly after this time point. The chemical composition of alfalfa silage was not affected by MI at 56 d of ensiling. The strain P. pentosaceus 6.16 was the most efficient in dominating the fermentation process by decreasing the pH more quickly and increasing the concentration

  15. Development of the Conceptual Models for Chemical Conditions and Hydrology Used in the 1996 Performance Assessment for the Waste Isolation Pilot Plant

    Energy Technology Data Exchange (ETDEWEB)

    LARSON, KURT W

    2000-05-24

    The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) facility for the permanent disposal of defense-related transuranic (TRU) waste. US Environmental Protection Agency (EPA) regulations specify that the DOE must demonstrate on a sound basis that the WIPP disposal system will effectively contain long-lived alpha-emitting radionuclides within its boundaries for 10,000 years following closure. In 1996, the DOE submitted the ''40 CFR Part 191 Compliance Certification Application for the Waste Isolation Pilot Plant'' (CCA) to the EPA. The CCA proposed that the WIPP site complies with EPA's regulatory requirements. Contained within the CCA are descriptions of the scientific research conducted to characterize the properties of the WIPP site and the probabilistic performance assessment (PA) conducted to predict the containment properties of the WIPP disposal system. In May 1998, the EPA certified that the TRU waste disposal at the WIPP complies with its regulations. Waste disposal operations at WIPP commenced on March 28, 1999. The 1996 WIPP PA model of the disposal system included conceptual and mathematical representations of key hydrologic and geochemical processes. These key processes were identified over a 22-year period involving data collection, data interpretation, computer models, and sensitivity studies to evaluate the importance of uncertainty and of processes that were difficult to evaluate by other means. Key developments in the area of geochemistry were the evaluation of gas generation mechanisms in the repository; development of a model of chemical conditions in the repository and actinide concentrations in brine; selecting MgO backfill and demonstrating its effects experimentally; and determining the chemical retardation capability of the Culebra. Key developments in the area of hydrology were evacuating the potential for groundwater to dissolve the Salado Formation (the repository host formation), development

  16. Development of the Conceptual Models for Chemical Conditions and Hydrology Used in the 1996 Performance Assessment for the Waste Isolation Pilot Plant

    International Nuclear Information System (INIS)

    The Waste Isolation Pilot Plant (WIPP) is a US Department of Energy (DOE) facility for the permanent disposal of defense-related transuranic (TRU) waste. US Environmental Protection Agency (EPA) regulations specify that the DOE must demonstrate on a sound basis that the WIPP disposal system will effectively contain long-lived alpha-emitting radionuclides within its boundaries for 10,000 years following closure. In 1996, the DOE submitted the ''40 CFR Part 191 Compliance Certification Application for the Waste Isolation Pilot Plant'' (CCA) to the EPA. The CCA proposed that the WIPP site complies with EPA's regulatory requirements. Contained within the CCA are descriptions of the scientific research conducted to characterize the properties of the WIPP site and the probabilistic performance assessment (PA) conducted to predict the containment properties of the WIPP disposal system. In May 1998, the EPA certified that the TRU waste disposal at the WIPP complies with its regulations. Waste disposal operations at WIPP commenced on March 28, 1999. The 1996 WIPP PA model of the disposal system included conceptual and mathematical representations of key hydrologic and geochemical processes. These key processes were identified over a 22-year period involving data collection, data interpretation, computer models, and sensitivity studies to evaluate the importance of uncertainty and of processes that were difficult to evaluate by other means. Key developments in the area of geochemistry were the evaluation of gas generation mechanisms in the repository; development of a model of chemical conditions in the repository and actinide concentrations in brine; selecting MgO backfill and demonstrating its effects experimentally; and determining the chemical retardation capability of the Culebra. Key developments in the area of hydrology were evacuating the potential for groundwater to dissolve the Salado Formation (the repository host formation), development of a regional model for

  17. Chemical evolution of RNA under hydrothermal conditions and the role of thermal copolymers of amino acids for the prebiotic degradation and formation of RNA

    Science.gov (United States)

    Kawamura, K.; Nagahama, M.; Kuranoue, K.

    2005-01-01

    The roles of thermal copolymers of amino acids (TCAA) were studied for the prebiotic degradation of RNA. A weak catalytic ability of TCAA consisted of Glu, L-Ala, L-Val, L-Glu, L-Asp, and optionally L-His was detected for the cleavage of the ribose phosphodiester bond of a tetranucleotide (5'-dCrCdGdG) in aqueous solution at 80 degees C. The rate constants of the disappearance of 5'-dCrCdGdG were determined in aqueous solutions using different pH buffer and TCAA. The degradation rates were enhanced 1.3-3.0 times in the presence of TCAA at pH 7.5 and 8.0 at 80 degrees C, while the hydrolysis of oligoguanylate (oligo(G)) was accelerated about 1.6 times at pH 8.0. A weak inhibitory activity for the cleavage of oligo(G) was detected in the presence of 0.055 M TCAA-Std. On the other hand, our recent study on the influences of TCAA for the template-directed reaction of oligo(G) on a polycytidylic acid template showed that TCAA has an acceleration activity for the degradation of the activated nucleotide monomer and an acceleration activity for the formation of G5' ppG capped oligo(G). This series of studies suggest that efficient and selective catalytic or inhibitory activities for either the degradation or formation of RNA under hydrothermal conditions could have hardly emerged from the simple thermal condensation products of amino acids. A scenario is going to be deduced on the chemical evolution of enzymatic activities and RNA molecules concerning hydrothermal earth conditions. c2005 COSPAR. Published by Elsevier Ltd. All rights reserved.

  18. Effects of Thermal Radiation and Chemical Reaction on MHD Free Convection Flow past a Flat Plate with Heat Source and Convective Surface Boundary Condition

    Directory of Open Access Journals (Sweden)

    E.Hemalatha

    2015-09-01

    Full Text Available This paper analyzes the radiation and chemical reaction effects on MHD steady two-dimensional laminar viscous incompressible radiating boundary layer flow over a flat plate in the presence of internal heat generation and convective boundary condition. It is assumed that lower surface of the plate is in contact with a hot fluid while a stream of cold fluid flows steadily over the upper surface with a heat source that decays exponentially. The Rosseland approximation is used to describe radiative heat transfer as we consider optically thick fluids. The governing boundary layer equations are transformed into a system of ordinary differential equations using similarity transformations, which are then solved numerically by employing fourth order Runge-Kutta method along with shooting technique. The effects of various material parameters on the velocity, temperature and concentration as well as the skin friction coefficient, the Nusselt number, the Sherwood number and the plate surface temperature are illustrated and interpreted in physical terms. A comparison of present results with previously published results shows an excellent agreement.

  19. Lie group analysis for the effects of temperature-dependent fluid viscosity and chemical reaction on MHD free convective heat and mass transfer with variable stream conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kandasamy, Ramasamy, E-mail: future990@gmail.co [Faculty of Science, Arts and Heritage, University Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor (Malaysia); Ismoen, Muhaimin; Saim, Hashim Bin [Faculty of Science, Arts and Heritage, University Tun Hussein Onn Malaysia, 86400 Parit Raja, Batu Pahat, Johor (Malaysia)

    2010-01-15

    This paper concerns with a steady two-dimensional flow of an electrically conducting incompressible fluid over a vertical stretching surface. The flow is permeated by a uniform transverse magnetic field. The fluid viscosity is assumed to vary as a linear function of temperature. A scaling group of transformations is applied to the governing equations. The system remains invariant due to some relations among the parameters of the transformations. After finding three absolute invariants a third-order ordinary differential equation corresponding to the momentum equation and two second-order ordinary differential equation corresponding to energy and diffusion equations are derived. The equations along with the boundary conditions are solved numerically. It is found that the decrease in the temperature-dependent fluid viscosity makes the velocity to decrease with the increasing distance of the stretching sheet. At a particular point of the sheet the fluid velocity decreases with the decreasing viscosity but the temperature increases in this case. It is found that with the increase of magnetic field intensity the fluid velocity decreases but the temperature increases at a particular point of the heated stretching surface. Impact of chemical reaction in the presence of thermal radiation plays an important role on the concentration boundary layer. The results thus obtained are presented graphically and discussed.

  20. Defining asthma in genetic studies

    NARCIS (Netherlands)

    Koppelman, GH; Postma, DS; Meijer, G.

    1999-01-01

    Genetic studies have been hampered by the lack of a gold standard to diagnose asthma. The complex nature of asthma makes it more difficult to identify asthma genes. Therefore, approaches to define phenotypes, which have been successful in other genetically complex diseases, may be applied to define

  1. Computer modelling of the chemical speciation of caesium, uranium(VI) and neptunium(V) in human duodenal fluids under fasting conditions

    International Nuclear Information System (INIS)

    A model simulating the human duodenal contents under physiologically realistic, fasting conditions was developed using the joint expert speciation system (JESS) computer program and database and used to investigate the chemical speciation of caesium, uranium(VI) and neptunium(V). Over the pH range 5.0-9.0, and the concentration range 5x10-15-5x10-5 mol dm-3, caesium was predicted to occur predominantly as the absorbable free monovalent cation Cs+ (∼95%) with species such as CsHPO4- and CsCl representing the remainder. The presence or absence of sulphate at 2.1x10-3 mol dm-3 did not influence the predicted speciation. Uranium was predicted to be present entirely as a soluble, highly charged species, both in the absence and in the presence of sulphate. Between pH 5.0 and ∼6.5 the UO2H2(PO4)22- predominated, above this pH carbonate species, either UO2(CO3)46- or, possibly, UO2(CO3)58-. At pH 8.0, and in the presence of sulphate, neptunium(V) was predicted to exist solely as the tetrasulphate species, whilst in the absence of sulphate, an array of negatively charged soluble carbonate species predominated. Studies over the pH range 5.0-9.0 predicted the formation of a spectrum of negatively charged carbonate and phosphate species, ∼40% of the total neptunium was predicted to be present as the electrically net-neutral species NpO2HCO3 at pH6.0, ∼20% at pH 7.0, ∼10% at pH 7.5 and ∼1% at pH 8.0. The observed speciation patterns of uranium and neptunium did not change over the concentration range 5x10-15-5x10-5 mol dm-3 and no solid species were predicted to occur under the conditions simulated. Whether the predicted electrically net-neutral neptunium species or the uranium pentacarbonate species do actually occur under true physiological conditions remains to be established. The observed speciation patterns for caesium and uranium are consistent with the observed absorption of these elements by humans; however, the observations for neptunium appear to be

  2. Mobility of major and trace elements in andosols from Iceland: correlating extent of chemical weathering with climatic conditions at soil formation sites

    Science.gov (United States)

    Oskarsson, Birgir V.; Riishuus, Morten S.; Arnalds, Olafur

    2010-05-01

    Element mobility within volcanic soil profiles developed in diverse climatic conditions in Iceland is assessed. Soils were selected from areas with good monitoring of annual temperature and precipitation and the degree of weathering and elemental behavior was compared. Most soils in Iceland develop in parent materials of volcanic origin, including a variety of basaltic and andesitic tephras, hyaloclastites and glacial tillites. Most Icelandic soils are subject to considerable flux of eolian deposition and in times receive tephra ejecta from volcanic eruptions. In this study, samples were carefully extracted from brown and gleyic andosol horizons for major and trace element analysis. Each horizon is representative of a pedogenetic stage. Preliminary results show that the major elements TiO2, Al2O3 and Fe2O3 (T) (mean wt% = 3.4, 19.2, 17.3) appear immobile relative to the parent material (p.m. mean wt% = 1.6, 14.6, 10.9) and are found enriched within more mature horizons. The base cations MgO, CaO and Na2O (mean wt% = 4.11, 7.23, 1.8) are depleted in these horizons (p.m. mean wt% = 9.1, 11.8, 2.0) showing mobilization during pedogenesis. The trace elements reveal no strong enrichment/depletion trend with a range of mobility from mobile to immobile Rb, Zn, Y, Sr, Ba, Ni, La, Cr, Cu, Nd, V, Zr and Nb. Soils developed in colder and dryer climatic conditions in Iceland (MAT = -1°C and MAP = 1000mm) show higher levels of weathering (CIA-K = 50-65) and element mobilization. The parent materials have a CIA-K weathering index of 37. The relationship of the covariance of the climate parameters with extent of chemical weathering may be quantified as climofunctions to deliver proxy climate data under cool to subarctic conditions. Our results may yield reasonable tools for determining past climate variations from weathered tephras found as paleosols in the Neogene lava piles of Iceland and other volcanic provinces.

  3. Equilibrium Chemical Engines

    OpenAIRE

    Shibata, Tatsuo; Sasa, Shin-ichi

    1997-01-01

    An equilibrium reversible cycle with a certain engine to transduce the energy of any chemical reaction into mechanical energy is proposed. The efficiency for chemical energy transduction is also defined so as to be compared with Carnot efficiency. Relevance to the study of protein motors is discussed. KEYWORDS: Chemical thermodynamics, Engine, Efficiency, Molecular machine.

  4. Defined Contribution vs Defined Pension: Reforming the Legal Retirement Age

    OpenAIRE

    Lacomba, Juan Antonio; Lagos, Francisco Miguel

    2008-01-01

    In this paper we analyze the effects of changing Social Security parameters on the optimal legal retirement age. Two Social Security Systems are studied, with opposite results. When the pension scheme has a defined contribution, a more redistributive system will delay the preferred legal retirement age. On the other hand, when the pension benefit is the defined parameter, the increase in the redistribution level will lower this preferred age.

  5. Defining Modules, Modularity and Modularization

    DEFF Research Database (Denmark)

    Miller, Thomas Dedenroth; Pedersen, Per Erik Elgård

    The paper describes the evolution of the concept of modularity in a historical perspective. The main reasons for modularity are: create variety, utilize similarities, and reduce complexity. The paper defines the terms: Module, modularity, and modularization....

  6. Theoretical approaches to elections defining

    OpenAIRE

    Natalya V. Lebedeva

    2011-01-01

    Theoretical approaches to elections defining develop the nature, essence and content of elections, help to determine their place and a role as one of the major national law institutions in democratic system.

  7. Chemical evolution and life

    OpenAIRE

    Malaterre Christophe

    2015-01-01

    In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before na...

  8. Defining safety goals. 2. Basic Consideration on Defining Safety Goals

    International Nuclear Information System (INIS)

    The purpose of this study is to develop basic safety goals that are rational and consistent for all nuclear facilities, including nuclear power plants and fuel cycle facilities. Basic safety goals (risk limits) by an index of radiation dose are discussed, which are based on health effects of detriment and fatality and risk levels presumably accepted by society. The contents of this paper are the personal opinions of the author. The desirable structure of safety goals is assumed to be 'basic safety goals plus specific safety goals (or supplemental safety goals) for each sort of facility, which reflects their characteristics'. The requisites of the basic safety goals must include (a) rational bases (scientific and social), (b) comprehensiveness (common to all sorts of nuclear facilities covering from normal to accidental conditions), and (c) applicability. To meet the requirements, the basic safety goals might have to be a risk profile expression by an index of radiation dose. The societal rationality is consideration of absolute risk levels (10-6 or 10-7/yr) and/or relative risk factors (such as 0.1% of U.S. safety goals) that the general public accepts as tolerable. The following quantitative objectives are adopted in this study for protection of average individuals in the vicinity of a nuclear facility: 1. The additive annual radiation dose during normal operation must be -4/yr (health detriment), 2x10-6/yr (latent cancer and severe hereditary effects), and 10-7/yr (acute fatality) from the statistics in Japan. The radiation effects on human beings are determined by recommendations of UNSCEAR (Ref. 1) and ICRP. The health effects considered are non-severe stochastic health detriment, i.e., detectable opacities of lens of eye (threshold 5 0.5 to 2 Sv), depression of hematopoiesis of bone marrow (0.5 Sv), and depression of reproductive capability (temporary sterility of testes ) (0.15 Sv). The LD50/60 of acute fatality is ∼4 Sv, and fatalities by latent cancer and

  9. Defining and Classifying Interest Groups

    DEFF Research Database (Denmark)

    Baroni, Laura; Carroll, Brendan; Chalmers, Adam;

    2014-01-01

    The interest group concept is defined in many different ways in the existing literature and a range of different classification schemes are employed. This complicates comparisons between different studies and their findings. One of the important tasks faced by interest group scholars engaged in...... large-N studies is therefore to define the concept of an interest group and to determine which classification scheme to use for different group types. After reviewing the existing literature, this article sets out to compare different approaches to defining and classifying interest groups with a sample...... cluster actors according to a number of key background characteristics and second assess how the categories of the different interest group typologies relate to these clusters. We demonstrate that background characteristics do align to a certain extent with certain interest group types but also find...

  10. The effect of environmental conditions on the chemical composition of soybean seeds: deactivation of trypsin inhibitor and effect of microwave on some components of soybean seeds

    International Nuclear Information System (INIS)

    The effects of microwave treatment are investigated on trypsin inhibitor activity (TIA) and chemical composition of soybean seeds. TIA could be largely destroyed by microwave treatment; concentrations of water-soluble protein and lysine were also determined

  11. Sensitivity to grid resolution in the ability of a chemical transport model to simulate observed oxidant chemistry under high-isoprene conditions

    Science.gov (United States)

    Yu, Karen; Jacob, Daniel J.; Fisher, Jenny A.; Kim, Patrick S.; Marais, Eloise A.; Miller, Christopher C.; Travis, Katherine R.; Zhu, Lei; Yantosca, Robert M.; Sulprizio, Melissa P.; Cohen, Ron C.; Dibb, Jack E.; Fried, Alan; Mikoviny, Tomas; Ryerson, Thomas B.; Wennberg, Paul O.; Wisthaler, Armin

    2016-04-01

    Formation of ozone and organic aerosol in continental atmospheres depends on whether isoprene emitted by vegetation is oxidized by the high-NOx pathway (where peroxy radicals react with NO) or by low-NOx pathways (where peroxy radicals react by alternate channels, mostly with HO2). We used mixed layer observations from the SEAC4RS aircraft campaign over the Southeast US to test the ability of the GEOS-Chem chemical transport model at different grid resolutions (0.25° × 0.3125°, 2° × 2.5°, 4° × 5°) to simulate this chemistry under high-isoprene, variable-NOx conditions. Observations of isoprene and NOx over the Southeast US show a negative correlation, reflecting the spatial segregation of emissions; this negative correlation is captured in the model at 0.25° × 0.3125° resolution but not at coarser resolutions. As a result, less isoprene oxidation takes place by the high-NOx pathway in the model at 0.25° × 0.3125° resolution (54 %) than at coarser resolution (59 %). The cumulative probability distribution functions (CDFs) of NOx, isoprene, and ozone concentrations show little difference across model resolutions and good agreement with observations, while formaldehyde is overestimated at coarse resolution because excessive isoprene oxidation takes place by the high-NOx pathway with high formaldehyde yield. The good agreement of simulated and observed concentration variances implies that smaller-scale non-linearities (urban and power plant plumes) are not important on the regional scale. Correlations of simulated vs. observed concentrations do not improve with grid resolution because finer modes of variability are intrinsically more difficult to capture. Higher model resolution leads to decreased conversion of NOx to organic nitrates and increased conversion to nitric acid, with total reactive nitrogen oxides (NOy) changing little across model resolutions. Model concentrations in the lower free troposphere are also insensitive to grid resolution. The

  12. OPTIMIZATION OF THE CONDITIONS REQUIRED FOR CHEMICAL AND BIOLOGICAL MODIFICATION OF THE YEAST WASTE FROM BEER MANUFACTURING TO PRODUCE ADHESIVE COMPOSITIONS

    OpenAIRE

    Davud Kadimaliev,; Vladimir Telyatnik,; Victor Revin,; Alexander Parshin,; Surhay Allahverdi,; Gokhan Gunduz; Elena Kezina,; Nejla Asık

    2012-01-01

    During the production of beer large amounts of yeast waste are generated. This paper considers the possible making of environmentally friendly adhesive compositions from such wastes. Chemical treatment of yeast wastes increases their adhesive characteristics. Chemical cross-linking with glutaric aldehyde and biological cross-linking by enzyme transglutaminase improves the moisture resistance of the adhesive compositions. In terms of their physical and mechanical parameters they are not inferi...

  13. Defining and Classifying Interest Groups

    DEFF Research Database (Denmark)

    Baroni, Laura; Carroll, Brendan; Chalmers, Adam; Marquez, Luz Maria Muñoz; Rasmussen, Anne

    2014-01-01

    The interest group concept is defined in many different ways in the existing literature and a range of different classification schemes are employed. This complicates comparisons between different studies and their findings. One of the important tasks faced by interest group scholars engaged in l...

  14. Defining a region of optimization based on engine usage data

    Science.gov (United States)

    Jiang, Li; Lee, Donghoon; Yilmaz, Hakan; Stefanopoulou, Anna

    2015-08-04

    Methods and systems for engine control optimization are provided. One or more operating conditions of a vehicle engine are detected. A value for each of a plurality of engine control parameters is determined based on the detected one or more operating conditions of the vehicle engine. A range of the most commonly detected operating conditions of the vehicle engine is identified and a region of optimization is defined based on the range of the most commonly detected operating conditions of the vehicle engine. The engine control optimization routine is initiated when the one or more operating conditions of the vehicle engine are within the defined region of optimization.

  15. Defining and managing sustainable yield.

    Science.gov (United States)

    Maimone, Mark

    2004-01-01

    Ground water resource management programs are paying increasing attention to the integration of ground water and surface water in the planning process. Many plans, however, show a sophistication in approach and presentation that masks a fundamental weakness in the overall analysis. The plans usually discuss issues of demand and yield, yet never directly address a fundamental issue behind the plan--how to define sustainable yield of an aquifer system. This paper points out a number of considerations that must be addressed in defining sustainable yield in order to make the definition more useful in practical water resource planning studies. These include consideration for the spatial and temporal aspects of the problem, the development of a conceptual water balance, the influence of boundaries and changes in technology on the definition, the need to examine water demand as well as available supply, the need for stakeholder involvement, and the issue of uncertainty in our understanding of the components of the hydrologic system. PMID:15584295

  16. Chemical Reduction of CO2 to Different Products during Photo Catalytic Reaction on TiO2 under Diverse Conditions: an Overview

    Institute of Scientific and Technical Information of China (English)

    G.R.Dey

    2007-01-01

    The chemical reduction of CO2 remains a challenge with respect to the reversal of the oxidative degradation of any organic materials.The conversion of CO2 into useful substances is essential in developing alternative fuels and various raw materials for different industries.This also aids in preventing the continuous rise in tropospheric temperature due to the green house effect of CO2.In this article an overview of the growth taken place so far in the field of CO2 chemical reduction is presented.The discussion comprises of photochemical methods for the development of different products,viz.CO,CH3OH and CH4,through chemical reduction of CO2.This includes the use of photo catalysts,mainly TiO2,and the role of a hole scavenger(such as 2-propan01) for this purpose.

  17. Defining Clusters of Related Industries

    OpenAIRE

    Mercedes Delgado; Porter, Michael E.; Scott Stern

    2014-01-01

    Clusters are geographic concentrations of industries related by knowledge, skills, inputs, demand, and/or other linkages. A growing body of empirical literature has shown the positive impact of clusters on regional and industry performance, including job creation, patenting, and new business formation. There is an increasing need for cluster-based data to support research, facilitate comparisons of clusters across regions, and support policymakers and practitioners in defining regional strate...

  18. Defining the TECHNOLOGY TRANSFER ALLIANCE

    OpenAIRE

    Ahlbom, Gabriella; Åman, Anna

    2011-01-01

    The aim of this project was to define the Technology Transfer Alliance (TTA), a nonprofit organization for Higher Education Institutions supporting capacity building in ICT and renewable energy through a project-driven learning. TTA is today still only an idea, waiting to be launched, which is why the goals for this bachelor thesis are to establish partnerships with institutions that will support the reaching of the goals of TTA, as well as providing a more solid definition of the functions o...

  19. Network Coded Software Defined Networking

    DEFF Research Database (Denmark)

    Krigslund, Jeppe; Hansen, Jonas; Roetter, Daniel Enrique Lucani;

    2015-01-01

    Software Defined Networking (SDN) and Network Coding (NC) are two key concepts in networking that have garnered a large attention in recent years. On the one hand, SDN's potential to virtualize services in the Internet allows a large flexibility not only for routing data, but also to manage buffe......). Our results on single–hop, multi–hop, and multi–path scenarios show that gains of 3x to 11x are attainable over standard TCP and multi–path TCP....

  20. The definability of physical concepts

    Directory of Open Access Journals (Sweden)

    Adonai S. Sant'Anna

    2005-11-01

    Full Text Available Our main purpose here is to make some specific considerations about the definability of physical concepts like mass, force, time, space, spacetime, and closed systems in the context of physical theories. Our starting motivation is a simple example of a collection of definitions of closed system in the literature of physics and philosophy of physics. Next we discuss the problem of definitions in theoretical physics from the point of view of modern theories of definition.

  1. The definability of physical concepts

    OpenAIRE

    Adonai S. Sant'Anna

    2005-01-01

    Our main purpose here is to make some specific considerations about the definability of physical concepts like mass, force, time, space, spacetime, and closed systems in the context of physical theories. Our starting motivation is a simple example of a collection of definitions of closed system in the literature of physics and philosophy of physics. Next we discuss the problem of definitions in theoretical physics from the point of view of modern theories of definition.

  2. Software Defined Radio Transceiver Implementation

    OpenAIRE

    Corley, Gerry; Sanchez Mora , Magdalena; Farrell, Ronan

    2008-01-01

    This document presents the design and implementation of a low cost reconfigurable radio transceiver platform. The platform will be used as a research tool in the investigation of software defined radio techniques. The hardware presented is an evolution of work presented at the 2006 RIA colloquium. The platform consists of four hardware elements, namely a radio transmitter, a radio receiver, a baseband interface and a PC to perform signal processing and configuration. Data and control c...

  3. Defining and teaching veterinary professionalism

    OpenAIRE

    Mossop, Liz

    2012-01-01

    Despite extensive research and discussion around the notion of medical professionalism, veterinary professionalism is an understudied area. The aim of this study was to define the concept of veterinary professionalism and analyse the hidden curriculum of a new veterinary school, in order to produce a new curriculum of professionalism. This study used a constructivist grounded theory method to develop the definition. An iterative approach, using interviews and focus groups, collected inform...

  4. Defining and measuring ecological specialization

    OpenAIRE

    Devictor, Vincent; Clavel, Joanne; Julliard, Romain; Lavergne, Sébastien; Mouillot, David; Thuiller, Wilfried; Venail, Patrick; Villéger, Sébastien; Mouquet, Nicolas

    2010-01-01

    1.  Ecological specialization is one of the main concepts in ecology and conservation. However, this concept has become highly context-dependent and is now obscured by the great variability of existing definitions and methods used to characterize ecological specialization. 2.  In this study, we clarify this concept by reviewing the strengths and limitations of different approaches commonly used to define and measure ecological specialization. We first show that ecological specialization can e...

  5. Defining Explanation in Probabilistic Systems

    OpenAIRE

    Chajewska, Urszula; Joseph Y. Halpern

    2013-01-01

    As probabilistic systems gain popularity and are coming into wider use, the need for a mechanism that explains the system's findings and recommendations becomes more critical. The system will also need a mechanism for ordering competing explanations. We examine two representative approaches to explanation in the literature - one due to G\\"ardenfors and one due to Pearl - and show that both suffer from significant problems. We propose an approach to defining a notion of "better explanation" th...

  6. Hydrothermal alteration zones and present reservoir conditions: an approach to define production zones at the eastern portion of the Cerro Prieto geothermal field, BC; Zonas de alteracion hidrotermal y condiciones actuales del yacimiento: un enfoque para determinar zonas productoras al oriente del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Camacho Hernandez, Juan Manuel [Comision Federal de Electricidad, Residencia General de Cerro Prieto, Mexicali, Baja California (Mexico)]. E-mail: juan.camacho02@cfe.gob.mx

    2009-07-15

    Geological factors are as essential for locating new wells as they are for defining the production zones of these wells. At the Cerro Prieto geothermal field (CGCP), one of the most important geological factors is identification of the hydrothermal alteration zones (ZAH). These are divided into silica and epidote mineralogical zones (ZMSE), without CaCO{sub 3}, and silica and epidote mineralogical transition zones (ZTMSE), with CaCO{sub 3}. It has been observed that the continuous variation of reservoir thermodynamic conditions (temperature, pressure and enthalpy) is due mainly to the exploitation of geothermal resources. The presence of new thermodynamic conditions recorded at the reservoir has led to the re-location of production wells originally located during the drilling campaign of 2004 to 2006. At the geological sections on the eastern part of the CGCP, adjustments made to the well completions lie on the limits between the ZMSE and ZTMSE zones. In turn, this is related to the current, superior, thermodynamic reservoir conditions. Based on this, a new geologic approach is proposed to define possible production zones for new wells, relating the ZAH zones to current thermodynamic reservoir conditions. [Spanish] Los factores geologicos son determinantes, tanto para establecer nuevos sitios de perforacion como para determinar el intervalo productor de un pozo nuevo. En el campo geotermico de Cerro Prieto (CGCP) una de los factores mas importantes es la determinacion de las zonas de alteracion hidrotermal (ZAH) que se dividen en dos: zona mineralogica de silice y epidota (ZMSE), sin presencia de CaCO{sub 3}, y zona de transicion mineralogica de silice y epidota (ZTMSE), con presencia de CaCO{sub 3}. Por otra parte, tambien se ha constatado que la continua variacion de las condiciones termodinamicas del yacimiento (temperatura, presion y entalpia) es originada en buena medida por la explotacion del recurso geotermico. La ocurrencia de nuevas condiciones

  7. Hydrologic conditions and distribution of selected radiochemical and chemical constituents in water, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho, 1992 through 1995

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomay, R.C.; Tucker, B.J.; Ackerman, D.J.; Liszewski, M.J.

    1997-04-01

    Radiochemical and chemical wastewater discharged since 1952 to infiltration ponds and disposal wells at the Idaho National Engineering Laboratory (INEL) has affected water quality in the Snake River Plain aquifer. The US Geological Survey, in cooperation with the US Department of Energy, maintains a monitoring network at the INEL to determine hydrologic trends and to delineate the movement of radiochemical and chemical wastes in the aquifer. This report presents an analysis of water-level and water-quality data collected from the Snake River Plain aquifer during 1992--95.

  8. Hydrologic conditions and distribution of selected radiochemical and chemical constituents in water, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho, 1992 through 1995

    International Nuclear Information System (INIS)

    Radiochemical and chemical wastewater discharged since 1952 to infiltration ponds and disposal wells at the Idaho National Engineering Laboratory (INEL) has affected water quality in the Snake River Plain aquifer. The US Geological Survey, in cooperation with the US Department of Energy, maintains a monitoring network at the INEL to determine hydrologic trends and to delineate the movement of radiochemical and chemical wastes in the aquifer. This report presents an analysis of water-level and water-quality data collected from the Snake River Plain aquifer during 1992--95

  9. OPTIMIZATION OF THE CONDITIONS REQUIRED FOR CHEMICAL AND BIOLOGICAL MODIFICATION OF THE YEAST WASTE FROM BEER MANUFACTURING TO PRODUCE ADHESIVE COMPOSITIONS

    Directory of Open Access Journals (Sweden)

    Davud Kadimaliev,

    2012-02-01

    Full Text Available During the production of beer large amounts of yeast waste are generated. This paper considers the possible making of environmentally friendly adhesive compositions from such wastes. Chemical treatment of yeast wastes increases their adhesive characteristics. Chemical cross-linking with glutaric aldehyde and biological cross-linking by enzyme transglutaminase improves the moisture resistance of the adhesive compositions. In terms of their physical and mechanical parameters they are not inferior to glues of natural origin and can be used for bonding paper, cardboard, and wood. The bonding strength of paper was 421.8 N / m, and that of wood was 27.8 MPa.

  10. Methodology for evaluating lateral boundary conditions in the regional chemical transport model MATCH (v5.5.0) using combined satellite and ground-based observations

    Science.gov (United States)

    Andersson, E.; Kahnert, M.; Devasthale, A.

    2015-11-01

    Hemispheric transport of air pollutants can have a significant impact on regional air quality, as well as on the effect of air pollutants on regional climate. An accurate representation of hemispheric transport in regional chemical transport models (CTMs) depends on the specification of the lateral boundary conditions (LBCs). This study focuses on the methodology for evaluating LBCs of two moderately long-lived trace gases, carbon monoxide (CO) and ozone (O3), for the European model domain and over a 7-year period, 2006-2012. The method is based on combining the use of satellite observations at the lateral boundary with the use of both satellite and in situ ground observations within the model domain. The LBCs are generated by the global European Monitoring and Evaluation Programme Meteorological Synthesizing Centre - West (EMEP MSC-W) model; they are evaluated at the lateral boundaries by comparison with satellite observations of the Terra-MOPITT (Measurements Of Pollution In The Troposphere) sensor (CO) and the Aura-OMI (Ozone Monitoring Instrument) sensor (O3). The LBCs from the global model lie well within the satellite uncertainties for both CO and O3. The biases increase below 700 hPa for both species. However, the satellite retrievals below this height are strongly influenced by the a priori data; hence, they are less reliable than at, e.g. 500 hPa. CO is, on average, underestimated by the global model, while O3 tends to be overestimated during winter, and underestimated during summer. A regional CTM is run with (a) the validated monthly climatological LBCs from the global model; (b) dynamical LBCs from the global model; and (c) constant LBCs based on in situ ground observations near the domain boundary. The results are validated against independent satellite retrievals from the Aqua-AIRS (Atmospheric InfraRed Sounder) sensor at 500 hPa, and against in situ ground observations from the Global Atmospheric Watch (GAW) network. It is found that (i) the use of

  11. Exploring the planetary boundary for chemical pollution

    DEFF Research Database (Denmark)

    Diamond, Miriam L.; de Wit, Cynthia A.; Molander, Sverker;

    2015-01-01

    Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of...... ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales...... evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step...

  12. Computational non-chemically equilibrium model on the current zero simulation in a model N2 circuit breaker under the free recovery condition

    International Nuclear Information System (INIS)

    A non-chemically equilibrium (non-CE) model was established to investigate the N2 arc plasma in the decaying phase during the arc interruption, and was validated by comparison with the experimental results based on laser Thomson scattering. Unlike the conventional model assuming the local thermodynamic equilibrium (LTE), in this non-CE model, the magneto-hydro-dynamics (MHD) method was coupled with the reaction kinetics to obtain the time-dependent species compositions and properties. The current calculation took into account five species in hot gas and 22 chemical reactions in total. The time-dependent species compositions of hot N2 were derived from the mass conservation equation for each species, considering the effect of the convection, diffusion and the chemical reaction. The influence of the non-CE compositions on the arc decaying behavior was realized by updating the thermodynamic and transport properties at each iterative step. The results indicate that the non-CE model can result in the departure of the arc decaying behavior from the LTE model, because it alters the time evolution of the species composition and consequently changes the thermodynamic and transport properties. At the edge of the arc, the time evolutions of the species are dominant by both the diffusion and the chemical reactions while at the center of the arc they are mainly influenced by the chemical reactions. Generally, the non-CE effect can lead to the delay of all the particles’ variations, particularly the electron decay, so that the arc interruption performance will be reduced compared with that in the LTE model. (paper)

  13. Computational non-chemically equilibrium model on the current zero simulation in a model N2 circuit breaker under the free recovery condition

    Science.gov (United States)

    Sun, Hao; Tanaka, Yasunori; Tomita, Kentaro; Wu, Yi; Rong, Mingzhe; Uesugi, Yoshihiko; Ishijima, Tatsuo

    2016-02-01

    A non-chemically equilibrium (non-CE) model was established to investigate the N2 arc plasma in the decaying phase during the arc interruption, and was validated by comparison with the experimental results based on laser Thomson scattering. Unlike the conventional model assuming the local thermodynamic equilibrium (LTE), in this non-CE model, the magneto-hydro-dynamics (MHD) method was coupled with the reaction kinetics to obtain the time-dependent species compositions and properties. The current calculation took into account five species in hot gas and 22 chemical reactions in total. The time-dependent species compositions of hot N2 were derived from the mass conservation equation for each species, considering the effect of the convection, diffusion and the chemical reaction. The influence of the non-CE compositions on the arc decaying behavior was realized by updating the thermodynamic and transport properties at each iterative step. The results indicate that the non-CE model can result in the departure of the arc decaying behavior from the LTE model, because it alters the time evolution of the species composition and consequently changes the thermodynamic and transport properties. At the edge of the arc, the time evolutions of the species are dominant by both the diffusion and the chemical reactions while at the center of the arc they are mainly influenced by the chemical reactions. Generally, the non-CE effect can lead to the delay of all the particles’ variations, particularly the electron decay, so that the arc interruption performance will be reduced compared with that in the LTE model.

  14. Chemical warfare in freshwater

    NARCIS (Netherlands)

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  15. Software Defined DCF77 Receiver

    OpenAIRE

    F. Zaplata; M. Kasal

    2013-01-01

    This paper shows the solution of time stamp software defined receiver integration into low cost com-mercial devices. The receiver is based on a general pur-pose processor and its analog to digital converter. The amplified signal from a narrow-band antenna is connected to the converter and no complicated filtration has to be used. All signal processing is digitally provided by the processor. During signal reception, the processor stays available for its main tasks and signal processing con-sum...

  16. Software Defined DCF77 Receiver

    Directory of Open Access Journals (Sweden)

    F. Zaplata

    2013-12-01

    Full Text Available This paper shows the solution of time stamp software defined receiver integration into low cost com-mercial devices. The receiver is based on a general pur-pose processor and its analog to digital converter. The amplified signal from a narrow-band antenna is connected to the converter and no complicated filtration has to be used. All signal processing is digitally provided by the processor. During signal reception, the processor stays available for its main tasks and signal processing con-sumes only a small part of its computational power.

  17. Influence of Chemical Extraction Conditions on the Physicochemical and Functional Properties of Polysaccharide Gum from Durian (Durio zibethinus Seed

    Directory of Open Access Journals (Sweden)

    Bahareh Tabatabaee Amid

    2012-05-01

    Full Text Available Durian seed is an agricultural biomass waste of durian fruit. It can be a natural plant source of non-starch polysaccharide gum with potential functional properties. The main goal of the present study was to investigate the effect of chemical extraction variables (i.e., the decolouring time, soaking temperature and soaking time on the physicochemical properties of durian seed gum. The physicochemical and functional properties of chemically-extracted durian seed gum were assessed by determining the particle size and distribution, solubility and the water- and oil-holding capacity (WHC and OHC. The present work revealed that the soaking time should be considered as the most critical extraction variable affecting the physicochemical properties of crude durian seed gum.

  18. Hydrologic conditions and distribution of selected radiochemical and chemical constituents in water, Snake River Plain aquifer, Idaho National Engineering Laboratory, Idaho, 1989 through 1991

    International Nuclear Information System (INIS)

    Radiochemical and chemical wastewater discharged since 1952 to infiltration ponds and disposal wells at the Idaho National Engineering Laboratory (INEL) has affected water quality in the Snake River Plain aquifer. The U.S. Geological Survey, in cooperation with the U.S. Department of Energy, maintains a continuous monitoring network at the INEL to determine hydrologic trends and to delineate the movement of radiochemical and chemical wastes in the aquifer. This report presents an analysis of water-level and water-quality data collected from the Snake River Plain aquifer during 1989-91. Water in the eastern Snake River Plain aquifer moves principally through fractures and interflow zones in basalt, generally flows southwestward, and eventually discharges at springs along the Snake River. The aquifer is recharged principally from irrigation water, infiltration of streamflow, and ground-water inflow from adjoining mountain drainage basins. Water levels in wells throughout the INEL generally declined during 1989-91 due to drought. Detectable concentrations of radiochemical constituents in water samples from wells in the Snake River Plain aquifer at the INEL decreased or remained constant during 1989-91. Decreased concentrations are attributed to reduced rates of radioactive-waste disposal, sorption processes, radioactive decay, and changes in waste-disposal practices. Detectable concentrations of chemical constituents in water from the Snake River Plain aquifer at the INEL were variable during 1989-91. Sodium and chloride concentrations in the southern part of the INEL increased slightly during 1989-91 because of increased waste-disposal rates and a lack of recharge from the Big Lost River. Plumes of 1,1,1-trichloroethane have developed near the Idaho Chemical Processing Plant and the Radioactive Waste Management Complex as a result of waste disposal practices

  19. Utilization of chemical fertilizers under tropial conditions. 2. Effect of nitrogen, phosphorus and potassium on the relationship between intercepted radiation and yield in potato crops in central Africa

    International Nuclear Information System (INIS)

    In several trials on the role of chemical fertilizers, closure of the canopy was examined with a 90 cm×80 cm quadrant and the relation between intercepted radiation and yield was determined. The rates of canopy closure in plots treated with different chemical fertilizers are shown in Fig. 1. An increase in yield but not in radiation interception was related to fertilization with potassium chloride. When the crop was harvested at different times in a similar trial, an increase in the efficiency of radiation utilization (EUR) occurred in the second half of the growing season, from 3.07 to 5.73 g/MJ (Fig. 3). This result was attributed to a greater foliage mass (Fig. 4) for the same extent of canopy closure resulting in a more efficient interception of radiation and also in greater translocation of carbohydrates from the leaves and stems to the tubers as the plants matured. Chemical fertilizers favoured leaf development at the beginning, and in the case of nitrogen, also at. end of the growth period (Fig. 5). EUR was especially sensitive to phosphorus and to a lesser extent to nitrogen and potassium (Fig. 6). An increase in EUR was related to a delay in tuberization resulting into an increase in the leaf area index even after canopy closure. The increase in EUR could also be explained by the higher number of tubers per plant acting as a more efficient sink for a rapid translocation of photosynthates

  20. Defining the space in a general spacetime

    Science.gov (United States)

    Arminjon, Mayeul

    2016-01-01

    A global vector field v on a “spacetime” differentiable manifold V, of dimension N + 1, defines a congruence of world lines: the maximal integral curves of v, or orbits. The associated global space Nv is the set of these orbits. A “v-adapted” chart on V is one for which the ℝN vector x ≡ (xj) (j = 1,…,N) of the “spatial” coordinates remains constant on any orbit l. We consider non-vanishing vector fields v that have non-periodic orbits, each of which is a closed set. We prove transversality theorems relevant to such vector fields. Due to these results, it can be considered plausible that, for such a vector field, there exists in the neighborhood of any point X ∈V a chart χ that is v-adapted and “nice”, i.e. such that the mapping χ¯ : l↦x is injective — unless v has some “pathological” character. This leads us to define a notion of “normal” vector field. For any such vector field, the mappings χ¯ build an atlas of charts, thus providing Nv with a canonical structure of differentiable manifold (when the topology defined on Nv is Hausdorff, for which we give a sufficient condition met in important physical situations). Previously, a local space manifold MF had been associated with any “reference frame” F, defined as an equivalence class of charts. We show that, if F is made of nice v-adapted charts, MF is naturally identified with an open subset of the global space manifold Nv.

  1. Smooth Pursuit of Flicker-Defined Motion

    Science.gov (United States)

    Mulligan, Jeffrey B.; Stevenson, Scott B.

    2014-01-01

    We examined the pursuit response to stimuli defined by space-variant flicker of a dense random dot carrier pattern. On each frame, every element of the pattern could change polarity, with a probability given by a two-dimensional Gaussian distribution. A normal distribution produces a circular region of twinkle, while inverting the distribution results in a spot of static texture in a twinkling surround. In this latter case, the carrier texture could be stationary, or could move with the twinkle modulator, thereby producing first-order motion in the region of the spot. While the twinkle-defined spot produces a strong sensation of motion, the complementary stimulus defined by the absence of twinkle does not, when viewed peripherally, it appears to move in steps even when the generating distribution moves smoothly. We examined pursuit responses to these stimuli using two techniques: 1) the eye movement correlogram, obtained by cross-correlating eye velocity with the velocity of a randomly-moving stimulus; and 2) delayed visual feedback, where transient stabilization of a target can produce spontaneous oscillations of the eye, with a period empirically observed to vary linearly with the applied delay. Both techniques provide an estimate of the internal processing time, which can be as short as 100 milliseconds for a first-order target. Assessed by the correlogram method, the response to flicker-defined motion is delayed by more than 100 milliseconds, and significantly weaker (especially in the vertical dimension). When initially presented in the delayed feedback condition, purely saccadic oscillation is observed. One subject eventually developed smooth oscillations (albeit with significant saccadic intrusions), showing a period-versus-delay slope similar to that observed for first-order targets. This result is somewhat surprising, given that we interpret the slope of the period-versus-delay-function as reflecting the balance between position- and velocity

  2. Chemical stability of 99mTc–DTPA under aerobic and microbially mediated Fe(III)-reducing conditions in porous media

    International Nuclear Information System (INIS)

    99mTc–DTPA has been used as a conservative tracer to quantify water transport through porous media. However, more information on the reactivity of this 99mTc compound under varying geochemical conditions is desirable to better understand its potential uses. We measured the speciation of Tc following amendment of 99mTc–DTPA to batch systems spanning a range of controlled biogeochemical conditions. Our results suggest that 99mTc–DTPA is stable under the reducing conditions tested. However, freshly precipitated Al–ferrihydrite may displace Tc(IV) from DTPA in the absence of Fe(III)-reducing conditions. - Highlights: • 99mTc–DTPA has been used to quantify water transport through porous media • 99mTc–DTPA does not always behave conservatively • Iron mineral surfaces can sometimes competitively bind DTPA • Reactivity of 99mTc–DTPA should be evaluated according to factors discussed

  3. The accuracy of the crystal chemical parameters at high-pressure conditions from single-crystal X-ray diffraction in diamond-anvil cell

    DEFF Research Database (Denmark)

    Periotto, Benedetta

    applications also in the materials science as it can provide useful information about the properties and performance of new materials. Over the past decades, the research in this field has been strongly developed due to the advances in computer capabilities and to the technological improvements of X...... started with a comparison between two different DACs, in order to define the capabilities of one of the most common types of pressure device, the ETH-type DAC. Application examples of data quality analysis have been conducted on pyroxenes (NaInSi2O6, orthoenstatite MgSiO3 and LiCrSi2O6), which are...

  4. Defining Usability of PN Services

    DEFF Research Database (Denmark)

    Nicolajsen, Hanne Westh; Ahola, Titta; Fleury, Alexandre;

    In this deliverable usability and user experience are defined in relation to MAGNET Beyond technologies, and it is described how the main MAGNET Beyond concepts can be evaluated through the involvement of users. The concepts include the new "Activity based communication approach" for interacting...... with the MAGNET Beyond system, as well as the core concepts: Personal Network, Personal Network-Federation, Service Discovery, User Profile Management, Personal Network Management, Privacy and Security and Context Awareness. The overall plans for the final usability evaluation are documented based on...... the present status of the pilot services. The evaluation will be conducted on two pilot services, that are being implemented - the Lifestyle companion and the Icebreaker. The plan of the evaluation is to carry out combinations of different types of user evaluation methods. These are user panel...

  5. DEFINING BAD AND GOOD PROCRASTINATION

    OpenAIRE

    Nazaria Solferino

    2012-01-01

    Often people procrastinate unpleasant tasks for immediate gratification in doing nothing today. Therefore many scholars have been engaged in designing incentive schemes to avoid it. We think the process is very complicated and many features need to be analyzed, as the subjective evaluations of the probability of success and rewards. In this paper we explore these factors and analyse under what conditions procrastination is a bad decision, with negative consequences or, on the contrary, it is ...

  6. Software Defined Common Processing System (SDCPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Coherent Logix, Incorporated proposes the Software Defined Common Processing System (SDCPS) program to facilitate the development of a Software Defined Radio...

  7. Plastic ingestion by Flesh-footed Shearwaters (Puffinus carneipes): Implications for fledgling body condition and the accumulation of plastic-derived chemicals

    International Nuclear Information System (INIS)

    To provide much needed quantitative data on the lethal and sublethal effects of plastic pollution on marine wildlife, we sampled breast feathers and stomach contents from Flesh-footed Shearwater (Puffinus carneipes) fledglings in eastern Australia. Birds with high levels of ingested plastic exhibited reduced body condition and increased contaminant load (p < 0.05). More than 60% of fledglings exceed international targets for plastic ingestion by seabirds, with 16% of fledglings failing these targets after a single feeding (range: 0.13–3.21 g of plastic/feeding). As top predators, seabirds are considered sentinels of the marine environment. The amount of plastic ingested and corresponding damage to Flesh-footed Shearwater fledglings is the highest reported for any marine vertebrate, suggesting the condition of the Australian marine environment is poor. These findings help explain the ongoing decline of this species and are worrying in light of increasing levels of plastic pollution in our oceans. - Highlights: • Proportion of the shearwater population ingesting plastic increased over four years. • Shearwater body condition is negatively influenced by the amount of ingested plastic. • Shearwater contaminant load is positively related to the amount of ingested plastic. • Many chicks exceed international targets for ingested plastic after a single feeding. • Plastic ingestion in this study is the highest reported for any marine vertebrate. - Flesh-footed Shearwaters ingest large quantities of marine plastic, which is correlated with poor body condition and increased concentrations of trace metals such as chromium

  8. Effect of wall conditions on the self-limiting deposition of metal oxides by pulsed plasma-enhanced chemical vapor deposition

    International Nuclear Information System (INIS)

    Pulsed plasma-enhanced chemical vapor deposition has been engineered to deliver self-limiting growth (i.e., ∼A /pulse) of metal oxides such as Ta2O5 and Al2O3. In this process the reactor walls are alternately exposed to atomic oxygen and metal precursors. The degree of adsorption in the latter step can dramatically influence both deposition rates and film quality. The impact of precursor adsorption on the plasma and gas-phase composition in these systems was quantified using optical emission spectroscopy and quadrupole mass spectrometry, respectively. It is shown that the time scale for a complete adsorption on the chamber walls is much greater than gas-phase residence times. Adsorbed compounds significantly alter the reactor composition, particularly at the initiation of each plasma pulse. As a consequence, careful attention must be paid to reactor design and operation to control deposition rates and maintain film quality

  9. CHEMICAL AND PHYSICAL CONDITIONS IN MOLECULAR CLOUD CORE DC 000.4–19.5 (SL42) IN CORONA AUSTRALIS

    International Nuclear Information System (INIS)

    Chemical reactions in starless molecular clouds are heavily dependent on interactions between gas phase material and solid phase dust and ices. We have observed the abundance and distribution of molecular gases in the cold, starless core DC 000.4–19.5 (SL42) in Corona Australis using data from the Swedish ESO Submillimeter Telescope. We present column density maps determined from measurements of C18O (J = 2-1, 1-0) and N2H+ (J = 1-0) emission features. Herschel data of the same region allow a direct comparison to the dust component of the cloud core and provide evidence for gas phase depletion of CO at the highest extinctions. The dust color temperature in the core calculated from Herschel maps ranges from roughly 10.7 to 14.0 K. This range agrees with the previous determinations from Infrared Space Observatory and Planck observations. The column density profile of the core can be fitted with a Plummer-like density distribution approaching n(r) ∼ r –2 at large distances. The core structure deviates clearly from a critical Bonnor-Ebert sphere. Instead, the core appears to be gravitationally bound and to lack thermal and turbulent support against the pressure of the surrounding low-density material: it may therefore be in the process of slow contraction. We test two chemical models and find that a steady-state depletion model agrees with the observed C18O column density profile and the observed N(C18O) versus AV relationship.

  10. Defining the Little Ice Age

    Directory of Open Access Journals (Sweden)

    Ø. Paasche

    2010-10-01

    Full Text Available The "Little Ice Age" (LIA is possibly the best-documented climatic anomaly of the past. A wide range of datasets portrays a harsh climate that worsened living conditions, primarily in terms of cooler temperatures, for people across Europe sometime during the last millennium. Regardless of the vast amount of data covering the LIA, there is presently no consensus concerning its spatial manifestation (was it regional or global?, its temporal constraints (when did it start and end?, or the broad-scale dynamics associated with it (what mechanisms did it involve?, although there is no shortage of suggestions. Based on a new compilation of data reflecting atmospheric circulation at both high and low latitudes, we show that the LIA lasted for roughly 400 years (∼1400–1800 AD. During this period at least four major atmospheric circulation systems on Earth co-varied on decadal to centennial timescales: Northern Annular Mode (NAM, Intertropical Convergence Zone (ITCZ, El Nino-Southern Oscillation (ENSO and West African Monsoon (WAM. This pattern of convergence suggests that a strong coupling between these circulation systems was an important pre-condition for the realisation of the LIA.

  11. Exploring the planetary boundary for chemical pollution.

    Science.gov (United States)

    Diamond, Miriam L; de Wit, Cynthia A; Molander, Sverker; Scheringer, Martin; Backhaus, Thomas; Lohmann, Rainer; Arvidsson, Rickard; Bergman, Åke; Hauschild, Michael; Holoubek, Ivan; Persson, Linn; Suzuki, Noriyuki; Vighi, Marco; Zetzsch, Cornelius

    2015-05-01

    Rockström et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if "unacceptable global change" is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent, as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social

  12. Introduction to Galactic Chemical Evolution

    Science.gov (United States)

    Matteucci, Francesca

    2016-04-01

    In this lecture I will introduce the concept of galactic chemical evolution, namely the study of how and where the chemical elements formed and how they were distributed in the stars and gas in galaxies. The main ingredients to build models of galactic chemical evolution will be described. They include: initial conditions, star formation history, stellar nucleosynthesis and gas flows in and out of galaxies. Then some simple analytical models and their solutions will be discussed together with the main criticisms associated to them. The yield per stellar generation will be defined and the hypothesis of instantaneous recycling approximation will be critically discussed. Detailed numerical models of chemical evolution of galaxies of different morphological type, able to follow the time evolution of the abundances of single elements, will be discussed and their predictions will be compared to observational data. The comparisons will include stellar abundances as well as interstellar medium ones, measured in galaxies. I will show how, from these comparisons, one can derive important constraints on stellar nucleosynthesis and galaxy formation mechanisms. Most of the concepts described in this lecture can be found in the monograph by Matteucci (2012).

  13. Physico-chemical study of the thermal degradation of ions exchange resins of nuclear origin: research of conditions to limit the pollution transfer, application to electric cables

    International Nuclear Information System (INIS)

    The ions exchange resins are one solid form of radioactive wastes. They are found mainly during the demineralization operations of the water from reactors cooling systems. This study aims to determine the conditions of a thermal processing leading to the production of a smaller residue, containing the whole activity. A protocol is proposed and validated on resins allowing a decrease of the volume of 63% for 99,93% of the activity. (A.L.B.)

  14. Influence of Polish Climate Conditions on Content and the Chemical Variation of Volatiles in the Roots of Six Eleutherococcus Species and Their Potential Use

    Directory of Open Access Journals (Sweden)

    Daniel Załuski

    2015-08-01

    Full Text Available The aim of this study was the term of the climate influence on essential oil and aroma components of six Eleutherococcus species [E. senticosus (Rupr. & Maxim. Maxim., E. setchuensis (Harms Nakai, E. sessiliflorus (Rupr. & Maxim. S. Y. Hu, E. gracilistylus (W. W. Smith S. Y. Hu, E. henryi Oliv., E. divaricatus (Siebold & Zucc. S. Y. Hu ] cultivated in Poland. The hydrodistilled volatiles of the samples were ranged from 0.2% to 0.4%. The components of the determined volatiles were analyzed by GC/MS/MS. Thirty of the same compounds were present in all samples. Major components of the samples were (E,E-farnesol (43.6-6.9%, (E,Z-farnesol (7.2-0.7%, (Z,E-farnesol (1.4-0.1%, tetradecanoic acid (9.91-2.08%, and pentadecanoic acid (12.8-3.5%. Highest (E,E-farnesol content (43.6% was determined in the roots of E. divaricatus. This compound may be considered as chemical marker of the species. This is the first time, when the analysis of volatiles in the roots of Eleutherococcus spp. cultivated in Poland was performed. This study provides a platform for further investigation for the isolation and pharmacological activity of active principles.

  15. Influence of ball milling and annealing conditions on the properties of L1{sub 0} FePt nanoparticles fabricated by a new green chemical synthesis method

    Energy Technology Data Exchange (ETDEWEB)

    Hu, X. C., E-mail: xiaocaoh@udel.edu [Department of Materials Science and Engineering, University of Delaware, Newark, Delaware 19716 (United States); Capobianchi, A. [Istituto di Struttura della Materia. CNR, Rome (Italy); Gallagher, R. [Department of Mechanical Engineering, University of Delaware, Newark, Delaware 19716 (United States); Hadjipanayis, G. C. [Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)

    2014-05-07

    In this work, a new green chemical strategy for the synthesis of L1{sub 0} FePt alloy nanoparticles is reported. The precursor is a polycrystalline molecular complex (Fe(H{sub 2}O){sub 6}PtCl{sub 6}), in which Fe and Pt atoms are arranged on alternating planes and milled with NaCl to form nanocrystals. Then the mixture was annealed under reducing atmosphere (5% H{sub 2} and 95% Ar) at temperatures varying from 350 °C to 500 °C for 2 h with a heating rate of 5 °C/min. After the reduction, the mixture was washed with water to remove the NaCl and L1{sub 0} FePt nanoparticles were obtained. The X-Ray Diffraction pattern showed the presence of the characteristic peaks of the fct phase of FePt nanoparticles. Influence of precursor/NaCl ratio and ball milling time on particle size was investigated. Transmission electron microscopy images revealed that smaller precursor/NaCl ratio (10 mg/20 g) and longer milling time (15 h) lead to smaller particle size and narrower size distribution. Milling time does not influence the coercivity much but the decrease of the amount of precursor leads to a decrease of coercivity from 10.8 kOe to 4.8 kOe.

  16. Influence of ball milling and annealing conditions on the properties of L10 FePt nanoparticles fabricated by a new green chemical synthesis method

    Science.gov (United States)

    Hu, X. C.; Capobianchi, A.; Gallagher, R.; Hadjipanayis, G. C.

    2014-05-01

    In this work, a new green chemical strategy for the synthesis of L10 FePt alloy nanoparticles is reported. The precursor is a polycrystalline molecular complex (Fe(H2O)6PtCl6), in which Fe and Pt atoms are arranged on alternating planes and milled with NaCl to form nanocrystals. Then the mixture was annealed under reducing atmosphere (5% H2 and 95% Ar) at temperatures varying from 350 °C to 500 °C for 2 h with a heating rate of 5 °C/min. After the reduction, the mixture was washed with water to remove the NaCl and L10 FePt nanoparticles were obtained. The X-Ray Diffraction pattern showed the presence of the characteristic peaks of the fct phase of FePt nanoparticles. Influence of precursor/NaCl ratio and ball milling time on particle size was investigated. Transmission electron microscopy images revealed that smaller precursor/NaCl ratio (10 mg/20 g) and longer milling time (15 h) lead to smaller particle size and narrower size distribution. Milling time does not influence the coercivity much but the decrease of the amount of precursor leads to a decrease of coercivity from 10.8 kOe to 4.8 kOe.

  17. Effect of site conditions and tree species composition on physico-chemical properties of soil environment in the Western Carpathians area

    OpenAIRE

    Dušan Vavříček; Jan Pecháček

    2012-01-01

    The objective of pedological research conducted in the Kněhyně--Čertův mlýn National Nature Reserve was to verify to what extent the properties of the soil environment are influenced by: a) chemistry of soil-forming substrate, b) site conditions, c) species composition of forest stand. The results of this study document that the soil taxonomic units in the area of interest are of podzol character and that the altitudinal soil zonality has not developed there. The total content of basic macrob...

  18. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  19. Fundamental properties of differential equations with dynamically defined delayed feedback

    OpenAIRE

    Knipl, D. H.

    2013-01-01

    We consider an initial value problem for nonautonomous functional differential equations where the delay term is defined via the solution of another system of differential equations. We obtain the general existence and uniqueness result for the initial value problem by showing a Lipschitz property of the dynamically defined delayed feedback function and give conditions for the nonnegativity of solutions. We determine the steady-state solution of the autonomous system and obtain the linearized...

  20. Impact of environmental conditions on the chemical surface properties of Cu(In,Ga)(S,Se)2 thin-film solar cell absorbers

    International Nuclear Information System (INIS)

    Environmentally driven aging effects play a crucial role in thin-film solar cells based on Cu(In,Ga)(S,Se)2, both for long-term stability and short air exposure during production. For a better understanding of such effects, Cu(In,Ga)(S,Se)2 absorber surfaces were investigated by x-ray photoelectron and Auger electron spectroscopy after exposure to different environmental conditions. Identical absorbers were stored in a nitrogen atmosphere, in damp heat, and under ambient conditions for up to 14 days. We find varying degrees of diffusion of sulfur, copper, and sodium towards the surface, with potential impact on the electronic surface structure (band gap) and the properties of the interface to a buffer layer in a solar cell device. Furthermore, we observe an oxidation (in decreasing order) of indium, copper, and selenium (but no oxidation of sulfur). And finally, varying amounts of carbon- and oxygen-containing adsorbates are found. In particular, the findings suggest that, for ambient air exposure, sodium carbonate is formed at the surface

  1. Modelling the chemical behaviour of tellurium species in the reactor pressure vessel and the reactor cooling system under severe accident conditions

    International Nuclear Information System (INIS)

    This state of the art report contains information on the behaviour of tellurium and its compounds in the reactor pressure vessel and the reactor coolant system under light water reactor severe accident conditions. To characterise tellurium behaviour, it is necessary the previous knowledge of the species of tellurium released from the core, and simultaneity of its release with that of other materials which can alter the transport, for instance, control rod and structural materials. Release and transport experiments have been reviewed along with the models implemented in the codes which are used in the international community: TRAPMELT, RAFT, VICTORIA and SOPHIE. From the experiments, it can be concluded that other species different to Te2, such as tin telluride and cesium telluride, may be released from the fuel. That is why they must be considered in the transport phenomena. There is also experimental evidence of the strong interaction of Te2 with Inconel 600 and stainless steel of the pipe walls and structures, however this strong interaction is in competition with the interaction of tellurium with aerosols, which under severe accident conditions may represent an area greater than that of the primary system. It is for the absence of significant tellurium species in the transport models, and also for the interaction of tellurium with aerosols, for which some codes show the greatest deficiencies

  2. Defining and certifying green power

    International Nuclear Information System (INIS)

    Studies have shown that as electric utilities restructure from monopolistic utilities to competitive open access retailers, there is an increasing demand by individual and institutional customers for green power. In the United States, 17 electricity suppliers have offered customers the opportunity to buy energy generated from renewable sources such as photovoltaic panels, wind turbines and biomass. Twenty other utilities are conducting market research in preparation for offering a similar program. It was suggested that in order to help the customers make their choice based on accurate information, generating facilities should be obligated to provide credible information about the environmental performance of electricity supply through standardized environmental profile labels. A list of agreed upon environmental indicators and performance levels must be established so that the 'environmental friendliness' of different generating facilities can be measured. One of the problems in tackling this issue is that there is disagreement about what constitutes green power. Opinions range from wind and solar generation being the only two forms of green power, to including even natural gas and nuclear energy (i.e. under the right conditions). The two programs that are used for the certification of green power in Canada and the United States are Canada's Environmental Choice Program and California's Green-e Renewable Electricity Branding Program. This report describes the two programs and summarizes the results of interviews conducted on the definition and certification of green power. 15 refs

  3. STUDY OF PHYSIOLOGICAL RESPONSES OF EQUINES WITHOUT DEFINED BREED AND QUARTER HORSE TO THE CLIMATIC CONDITIONS OF TERESINA, PIAUÍ ESTUDO DE RESPOSTAS FISIOLÓGICAS DE EQÜINOS SEM RAÇA DEFINIDA E DA RAÇA QUARTO DE MILHA ÀS CONDIÇÕES CLIMÁTICAS DE TERESINA, PIAUÍ

    Directory of Open Access Journals (Sweden)

    Sílvia Helena Nogueira Turco

    2008-12-01

    Full Text Available This study was developed to evaluate the adaptability of without defined breed and Quarter Horses to the thermal conditions of Teresina, using physiological parameters using tolerance tests and heat dissipation. The measures of rectal temperature and heart and respiratory rates were collected in March and October. These months represents, respectively, the rainy period and the hot and dry period in the area studied. The response of each genetic group was evaluated using physiological parameters and adaptations indexes (Ibéria, Benezra and Rainysby tests. In each herd the experimental design was completely randomized and the statistical model included the effect of period of the year and/or schedule of measurement of the parameter. The thermal environment in the area during the dry period of the year hinders the homoeothermic maintenance in the animals, limiting the physical activities with horses. The physiological parameters suffered with an increase of the environmental temperature. The Quarter Horses were shown to be adapted to the environmental conditions, with small alterations in the rectal temperature caused by increment of the temperature. The hot thermal environment during the dry period of the year interfered in the homoeothermic behavior of the Without Defined Breed animals.

    KEY WORDS: Adaptation, indexes, rectal temperature, respiratory rate, thermal environment. Estudou-se, com eqüinos Sem Raça Definida e com animais da raça Quarto de Milha, o comportamento de parâmetros fisiológicos com objetivo de avaliar, por meio de testes de tolerância e de dissipação de calor, a adaptabilidade desses animais ao ambiente térmico de Teresina, PI. Coletaram-se as medidas de temperatura retal e as freqüências cardíaca e respiratória em março e outubro, período esse que representa, respectivamente, o período chuvoso e o quente e seco na região. A resposta de cada grupo genético foi avaliada utilizando-se os par

  4. High-sensitivity nuclear magnetic resonance at Giga-Pascal pressures: a new tool for probing electronic and chemical properties of condensed matter under extreme conditions.

    Science.gov (United States)

    Meier, Thomas; Haase, Jürgen

    2014-01-01

    Nuclear Magnetic Resonance (NMR) is one of the most important techniques for the study of condensed matter systems, their chemical structure, and their electronic properties. The application of high pressure enables one to synthesize new materials, but the response of known materials to high pressure is a very useful tool for studying their electronic structure and developing theories. For example, high-pressure synthesis might be at the origin of life; and understanding the behavior of small molecules under extreme pressure will tell us more about fundamental processes in our universe. It is no wonder that there has always been great interest in having NMR available at high pressures. Unfortunately, the desired pressures are often well into the Giga-Pascal (GPa) range and require special anvil cell devices where only very small, secluded volumes are available. This has restricted the use of NMR almost entirely in the past, and only recently, a new approach to high-sensitivity GPa NMR, which has a resonating micro-coil inside the sample chamber, was put forward. This approach enables us to achieve high sensitivity with experiments that bring the power of NMR to Giga-Pascal pressure condensed matter research. First applications, the detection of a topological electronic transition in ordinary aluminum metal and the closing of the pseudo-gap in high-temperature superconductivity, show the power of such an approach. Meanwhile, the range of achievable pressures was increased tremendously with a new generation of anvil cells (up to 10.1 GPa), that fit standard-bore NMR magnets. This approach might become a new, important tool for the investigation of many condensed matter systems, in chemistry, geochemistry, and in physics, since we can now watch structural changes with the eyes of a very versatile probe. PMID:25350694

  5. Improvement of chemical monitoring of water-chemistry conditions at thermal power stations based on electric conductivity and pH measurements

    Science.gov (United States)

    Larin, A. B.; Larin, B. M.

    2016-05-01

    The increased requirements to the quality of the water heat conductor for working superhigh (SHP) and supercritical (SCP) pressure power plants and promising units, including combined-cycle gas turbine (CCGT) units and power plants with ultrasupercritical parameters (USCPs), can largely be satisfied through specific electric conductivity and pH measurements for cooled heat conductor samples combined with calculations of ionic equilibria and indirect measurements of several specified and diagnostic parameters. The possibility of calculating the ammonia and chloride concentrations and the total concentration of hardness and sodium cations in the feed water of drum-type boilers and the phosphate and salt contents in boiler water was demonstrated. An equation for evaluating the content of potentially acid substances in the feed water of monotube boilers was suggested. The potential of the developed procedure for evaluating the state of waterchemistry conditions (WCCs) in power plants with CCGT units was shown.

  6. Chemical, thermal and mechanical stabilities of metal-organic frameworks

    Science.gov (United States)

    Howarth, Ashlee J.; Liu, Yangyang; Li, Peng; Li, Zhanyong; Wang, Timothy C.; Hupp, Joseph T.; Farha, Omar K.

    2016-03-01

    The construction of thousands of well-defined, porous, metal-organic framework (MOF) structures, spanning a broad range of topologies and an even broader range of pore sizes and chemical functionalities, has fuelled the exploration of many applications. Accompanying this applied focus has been a recognition of the need to engender MOFs with mechanical, thermal and/or chemical stability. Chemical stability in acidic, basic and neutral aqueous solutions is important. Advances over recent years have made it possible to design MOFs that possess different combinations of mechanical, thermal and chemical stability. Here, we review these advances and the associated design principles and synthesis strategies. We focus on how these advances may render MOFs effective as heterogeneous catalysts, both in chemically harsh condensed phases and in thermally challenging conditions relevant to gas-phase reactions. Finally, we briefly discuss future directions of study for the production of highly stable MOFs.

  7. Chemical reactions of actinides with groundwater colloids. Studies of transferability of laboratory data to natural conditions. The aquiferous system in Gorleben. Interim report. Reported period: 1.2.1993-31.12.1993

    International Nuclear Information System (INIS)

    This study deals with the chemical interreaction between actinides and groundwater-colloids in selected aquiferes in the overburden of the planned final storage site for radioactive matter near Gorleben (Lower Saxony). As colloids have other transport properties than dissolved metal ions the interaction of actinides and groundwater-colloids has an important influence on their migration and is therefore essentially important for longterm-safety analyses. In order to study interaction of actinides with groundwater-colloids selected groundwaters were conditioned with trace concentrations of the actinides TH, Np, Pu, Am and Cm. For hexavalent actinides one used the analytical data of natural uranium in the groundwaters. In order to determine the humic-colloid-bound parts of the actinides the conditioned ground waters were filtered with a pore width of 1 nm and actinide concentration was determined with radiometry. (orig./EF)

  8. Methodologies for defining quality of life

    Energy Technology Data Exchange (ETDEWEB)

    Glicken, J. [Ecological Planning and Toxicology, Inc., Albuquerque, NM (United States); Engi, D. [Sandia National Labs., Albuquerque, NM (United States)

    1996-10-10

    Quality of life as a concept has been used in many ways in the public policy arena. It can be used in summative evaluations to assess the impacts of policies or programs. Alternatively, it can be applied to formative evaluations to provide input to the formation of new policies. In short, it provides the context for the understanding needed to evaluate the results of choices that have been made in the public policy arena, or the potential of choices yet to be made. In either case, the public policy question revolves around the positive or negative impact the choice will have on quality of life, and the magnitude of that impact. This discussion will develop a conceptual framework that proposes that an assessment of quality of life is based on a comparison of expectations with experience. The framework defines four basic components from which these expectations arise: natural conditions, social conditions, the body, and the mind. Each one of these components is generally described, and associated with a general policy or rhetorical category which gives it its policy vocabulary--environmental quality, economic well-being, human health, and self-fulfillment.

  9. Characterization of selected biological, chemical, and physical conditions at fixed sites in the Upper Colorado River basin, Colorado, 1995-98

    Science.gov (United States)

    Deacon, Jeffrey R.; Mize, Scott V.; Spahr, Norman E.

    1999-01-01

    Biological community samples were collected at 15 sites in the Upper Colorado River Basin (UCOL) in Colorado as part of the National Water-Quality Assessment (NAWQA) Program. Sites sampled in two physiographic provinces, the Southern Rocky Mountains and the Colorado Plateau, represented agriculture, mining, urban and recreation, and mixed land uses and background conditions. Nine measures of water quality, which include information on nutrients, specific conductance (a surrogate for salinity), trace elements in streambed sediment, pesticides in fish tissue, fish communities, and macroinvertebrate richness and composition and stream habitat were used for comparisons among sites within the two physiographic provinces. Sampling sites from three other NAWQA study units?the Rio Grande Valley, the South Platte River Basin, and the Upper Snake River Basin study units?were categorized on the basis of land use and stream size in order to develop a larger data set for comparison to sites in the UCOL. Three categories of land use?forested (includes mining, urban and recreation, and background), agriculture, and mixed?were used for comparison to the UCOL fixed sites. Results indicated that all sites other than the Colorado River below Baker Gulch (a background site) showed some water-quality characteristics to be significantly affected. Results indicated that the concentrations of cadmium and zinc in streambed sediment at mining land-use sites in the Southern Rocky Mountains physiographic province generally were orders of magnitude higher than streambed-sediment concentrations at the background site. Streambed-sediment concentrations at mining land-use sites in the UCOL were greater than the 75th percentile of concentrations from sites in the three other NAWQA study units. Fish communities and habitat conditions were degraded at mining land-use sites compared to the background site. Ephemeroptera, Plecoptera, and Trichoptera (EPT) richness and the percentage of EPT were lower

  10. EVOLUTION OF CHEMICAL CONDITIONS AND ESTIMATED PLUTONIUM SOLUBILITY IN THE RESIDUAL WASTE LAYER DURING POST-CLOSURE AGING OF TANK 18

    Energy Technology Data Exchange (ETDEWEB)

    Denham, M.

    2012-02-29

    evolution. In Denham (2007, Rev. 1), the solubilities in the oxidized regions were estimated at Eh values in equilibrium with dissolved oxygen. Here, these are considered to be maximum possible solubilities because Eh values are unlikely to be in equilibrium with dissolved oxygen. More realistic Eh values are estimated here and plutonium solubilities calculated at these are considered more realistic. Apparent solubilities of plutonium that coprecipitated with iron phases are estimated from Pu:Fe ratios in Tank 18 residual waste and the solubilities of the host iron phases. The estimated plutonium solubilities are shown. Uncertainties in the grout simulations and plutonium solubility estimates are discussed. The primary uncertainty in the grout simulations is that little is known about the physical state of the grout as it ages. The simulations done here are pertinent to a porous medium, which may or may not be applicable to fractured grout, depending on the degree and nature of the fractures. Other uncertainties that are considered are the assumptions about the reducing capacity imparted by blast furnace slag, the effects of varying dissolved carbon dioxide and oxygen concentrations, and the treatment of silica in the simulations. The primary uncertainty in the estimates of plutonium solubility is that little is known about the exact form of plutonium in the residual waste. Other uncertainties include those inherent in the thermodynamic data, pH variations from those estimated in the grout simulations, the effects of the treatment of silica in the grout simulations, and the effect of varying total dissolved carbonate concentrations. The objective of this document is to update the model for solubility controls on release of plutonium from residual waste in closed F-Area waste tanks. The update is based on new information including a new proposed grout formulation, chemical analysis of Tank 18 samples and more current thermodynamic data for plutonium and grout minerals. In

  11. Influence of rhizobial and mycorrhizal symbioses on growth, nodulation and chemical composition of Acacia auriculiformis and Acacia mangium in salt stress conditions

    International Nuclear Information System (INIS)

    In arid and semi-arid regions soil salinity is a problem of grave concern because it adversely affects growth, establishment and productivity of plants in arid zone. A lot of rehabilitation programs have been attempted to restore sustainable ecosystems using Acacia species on the account of their positive impacts on environmental protection and in the local economies of dry and semi-arid tropical Africa. Research was undertaken in greenhouse conditions on soils in Senegal in order to compare the effectiveness of controlled inoculations with Bradyrhizobium strains, AM fungi (Glomus intraradices) and one fungal strain of Pisolithus albus alone and in combination on growth and nutrient uptake of A. auriculiformis and A. mangium plants under a wide range of salinity conditions. Application of three NaCl concentrations (0, 0.05 and 0.1 mol L-1) started three weeks after inoculation to allow time for the symbioses to develop. All pots, nine replications per inoculation treatment, were watered to excess with approximately 250 mL d-1. The electrical conductivity of the leachate from representative pots was monitored regularly to ascertain actual NaCl concentrations within the rooting medium and pots were flushed weekly with deonised water to avoid any increase in salt concentrations, then immediately watered with the designated treatment solution. The dry weight of both species decreased with increasing NaCl concentrations as compared with the controls but the effect of salt was more inhibitory on non-inoculated plants. For inoculated seedlings, the reduction of aerial dry weigh in A. auriculiformis was less than that of A. mangium. For A. auriculiformis, all inoculation treatments clearly improved the biomass production of salt-treated seedlings. Inoculation with the three symbionts Bradyrhizobium, Glomus intraradices and Pisolithus albus (RVaEc) enhanced total biomass production further than other treatments. At 100 mM NaCl the aerial biomass was increased to 112% of the

  12. Chemical warfare in freshwater

    OpenAIRE

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field experiments we studied the allelopathic effects of the aquatic macrophytes, Chara and Stratiotes. Laboratory experiments showed that the aquatic macrophytes had allelopathic effects. Phytoplankton grow...

  13. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    International Nuclear Information System (INIS)

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100–260 Torr pressure range and 1.5–2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (ηcoup) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance

  14. Effects of interlayer growth condition on the transport properties of heterostructures with InGaN channel grown on sapphire by metal organic chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yachao; Zhou, Xiaowei; Xu, Shengrui; Wang, Zhizhe; Zhao, Yi; Zhang, Jinfeng; Chen, Dazheng; Zhang, Jincheng, E-mail: jchzhang@xidian.edu.cn; Hao, Yue, E-mail: yhao@xidian.edu.cn [State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, No.2 South TaiBai Road, Xi' an 710071 (China)

    2015-04-13

    The effects of AlN interlayer growth condition on the properties of InAlN/InGaN heterostructures are investigated in detail. Since the properties of InGaN channel are different from the traditional GaN channel, two-step AlN interlayer is proposed, which is proven to be more suitable for the InGaN channel heterostructures than the interlayers grown at constant temperature. Test results show that two-step AlN interlayer can not only significantly improve the interface morphology between the InGaN channel and barrier layers but also make an effective protection of the high-quality InGaN channel. The electron mobility of the InAlN/InGaN heterostructure with two-step AlN interlayer achieves 890 cm{sup 2}/V s with a high two-dimensional-electron-gas density of 1.78 × 10{sup 13 }cm{sup −2}. The gratifying results indicate that the InGaN channel heterostructure with two-step interlayer is a promising candidate for microwave power devices.

  15. Experiences with archived raw diffraction images data: capturing cisplatin after chemical conversion of carboplatin in high salt conditions for a protein crystal

    Energy Technology Data Exchange (ETDEWEB)

    Tanley, Simon W. M. [University of Manchester, Brunswick Street, Manchester M13 9Pl (United Kingdom); Diederichs, Kay [University of Konstanz (Germany); Kroon-Batenburg, Loes M. J.; Schreurs, Antoine M. M. [Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Helliwell, John R., E-mail: john.helliwell@manchester.ac.uk [University of Manchester, Brunswick Street, Manchester M13 9Pl (United Kingdom)

    2013-10-01

    Archiving of raw diffraction images data has led to new structural chemistry information being obtained for previously published results, which leads to the conclusion that carboplatin has partially converted to cisplatin in the high NaCl concentration conditions used in the crystallization procedure. The archiving of raw diffraction images data is the focus of an IUCr Diffraction Data Deposition Working Group. Experience in archiving and sharing of raw diffraction images data in collaboration between Manchester and Utrecht Universities, studying the binding of the important anti-cancer agents, cisplatin and carboplatin to histidine in a protein, has recently been published. Subsequently, these studies have been expanded due to further analyses of each data set of raw diffraction images using the diffraction data processing program XDS. The raw diffraction images, measured at Manchester University, are available for download at Utrecht University and now also mirrored at the Tardis Raw Diffraction Data Archive in Australia. Thus a direct comparison of processed diffraction and derived protein model data from XDS with the published results has been made. The issue of conversion of carboplatin to cisplatin under a high chloride salt concentration has been taken up and a detailed crystallographic assessment is provided. Overall, these new structural chemistry research results are presented followed by a short summary of developing raw data archiving policy and practicalities as well as documenting the challenge of making appropriate and detailed recording of the metadata for crystallography.

  16. Determining the microwave coupling and operational efficiencies of a microwave plasma assisted chemical vapor deposition reactor under high pressure diamond synthesis operating conditions

    Science.gov (United States)

    Nad, Shreya; Gu, Yajun; Asmussen, Jes

    2015-07-01

    The microwave coupling efficiency of the 2.45 GHz, microwave plasma assisted diamond synthesis process is investigated by experimentally measuring the performance of a specific single mode excited, internally tuned microwave plasma reactor. Plasma reactor coupling efficiencies (η) > 90% are achieved over the entire 100-260 Torr pressure range and 1.5-2.4 kW input power diamond synthesis regime. When operating at a specific experimental operating condition, small additional internal tuning adjustments can be made to achieve η > 98%. When the plasma reactor has low empty cavity losses, i.e., the empty cavity quality factor is >1500, then overall microwave discharge coupling efficiencies (ηcoup) of >94% can be achieved. A large, safe, and efficient experimental operating regime is identified. Both substrate hot spots and the formation of microwave plasmoids are eliminated when operating within this regime. This investigation suggests that both the reactor design and the reactor process operation must be considered when attempting to lower diamond synthesis electrical energy costs while still enabling a very versatile and flexible operation performance.

  17. Experiences with archived raw diffraction images data: capturing cisplatin after chemical conversion of carboplatin in high salt conditions for a protein crystal

    International Nuclear Information System (INIS)

    Archiving of raw diffraction images data has led to new structural chemistry information being obtained for previously published results, which leads to the conclusion that carboplatin has partially converted to cisplatin in the high NaCl concentration conditions used in the crystallization procedure. The archiving of raw diffraction images data is the focus of an IUCr Diffraction Data Deposition Working Group. Experience in archiving and sharing of raw diffraction images data in collaboration between Manchester and Utrecht Universities, studying the binding of the important anti-cancer agents, cisplatin and carboplatin to histidine in a protein, has recently been published. Subsequently, these studies have been expanded due to further analyses of each data set of raw diffraction images using the diffraction data processing program XDS. The raw diffraction images, measured at Manchester University, are available for download at Utrecht University and now also mirrored at the Tardis Raw Diffraction Data Archive in Australia. Thus a direct comparison of processed diffraction and derived protein model data from XDS with the published results has been made. The issue of conversion of carboplatin to cisplatin under a high chloride salt concentration has been taken up and a detailed crystallographic assessment is provided. Overall, these new structural chemistry research results are presented followed by a short summary of developing raw data archiving policy and practicalities as well as documenting the challenge of making appropriate and detailed recording of the metadata for crystallography

  18. Chronic Conditions PUF

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Chronic Conditions PUFs are aggregated files in which each record is a profile or cell defined by the characteristics of Medicare beneficiaries. A profile is...

  19. On defining semantics of extended attribute grammars

    DEFF Research Database (Denmark)

    Madsen, Ole Lehrmann

    1980-01-01

    Knuth has introduced attribute grammars (AGs) as a tool to define the semanitcs of context-free languages. The use of AGs in connection with programming language definitions has mostly been to define the context-sensitive syntax of the language and to define a translation in code for a hypothetical...

  20. Defining moments in leadership character development.

    Science.gov (United States)

    Bleich, Michael R

    2015-06-01

    Critical moments in life define one's character and clarify true values. Reflective leadership is espoused as an important practice for transformational leaders. Professional development educators can help surface and explore defining moments, strengthen leadership behavior with defining moments as a catalyst for change, and create safe spaces for leaders to expand their leadership capacity. PMID:26057159

  1. Optimisation in radiotherapy I. Defining the problem

    International Nuclear Information System (INIS)

    Optimisation in radiotherapy should incorporate a very wide set of variables, including the combinations of dose due to external beam radiotherapy, brachytherapy, internally administered radionuclides and the effects of chemotherapy, surgery, hyperthermia, other biological and chemical defenses, alternative treatment techniques, lifestyle and mental state of the patient, the economics of cancer treatment and consideration of tolerable levels of adverse effects and palliation. A full treatment optimisation would consider the influence and covariance of all these variables and any future techniques, as well as the complex constraints imposed by the biological systems being irradiated. This series of reviews concentrates on optimisation of radiotherapy through the treatment planning component of the treatment process - an area of radiotherapy research that has received a great deal of attention as the attached lists of references will testify. It hopes to provide the medical physics and engineering community (and hopefully the clinical community) with a background into the mathematical bases for the manipulation of radiation for clinical benefit. It also examines the potential benefits of research into these techniques in the light of recent approaches to optimisation in radiotherapy, and provides pointers to more concise accounts in the literature. In this first article, the incentive for radiotherapy optimisation research is established, and the actual radiotherapy optimisation problem (in terms of the manipulation of degrees of freedom in radiation delivery) is defined. The degrees of freedom associated with radiotherapy treatment are identified, and it is shown how these degrees of freedom translate into the mathematical parameters of the problem, including the dose distributions they produce. The constraints and objectives of the problem are also discussed from both physical and radiobiological perspectives. (author)

  2. Characterization and definability in modal first-order fragments

    CERN Document Server

    Carreiro, Facundo

    2010-01-01

    Model theoretic results such as Characterization and Definability give important information about different logics. It is well known that the proofs of those results for several modal logics have, somehow, the same 'taste'. A general proof for most modal logics below first order is still too ambitious. In this thesis we plan to isolate sufficient conditions for the characterization and definability theorems to hold in a wide range of logics. Along with these conditions we will prove that, whichever logic that meets them, satisfies both theorems. Therefore, one could give an unifying proof for logics with already known results. Moreover, one will be able to prove characterization and definability results for logics that have not yet been investigated. In both cases, it is only needed to check that a logic meets the requirements to automatically derive the desired results.

  3. Multiple chemical sensitivity

    DEFF Research Database (Denmark)

    Tran, Marie Thi Dao; Arendt-Nielsen, Lars; Kupers, Ron;

    2013-01-01

    BACKGROUND: Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by recurrent, non-specific symptoms in response to chemically unrelated exposures in non-toxic concentrations. Although the pathophysiology of MCS remains unknown, central sensitization may be an important factor...

  4. The temporal calculus of conditional objects and conditional events

    OpenAIRE

    Tyszkiewicz, Jerzy; Ramer, Arthur; Hoffmann, Achim

    2001-01-01

    We consider the problem of defining conditional objects (a|b), which would allow one to regard the conditional probability Pr(a|b) as a probability of a well-defined event rather than as a shorthand for Pr(ab)/Pr(b). The next issue is to define boolean combinations of conditional objects, and possibly also the operator of further conditioning. These questions have been investigated at least since the times of George Boole, leading to a number of formalisms proposed for conditional objects, mo...

  5. Software Defined Networking (Dagstuhl Seminar 12363)

    OpenAIRE

    Hui, Pan; Koponen, Teemu

    2013-01-01

    This report documents the talks and discussions of Dagstuhl Seminar 12363 "Software Defined Networking". The presented talks represent a spectrum of industrial and academic work as well as both technical and organizational developments surrounding Software Defined Networking (SDN). The topic of SDN has garnered significant attention over the past few years in the networking community and beyond, and indeed the term "Software Defined Networking" itself carries different meani...

  6. Software Defined Common Processing System (SDCPS) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Coherent Logix, Incorporated (CLX) proposes the development of a Software Defined Common Processing System (SDCPS) that leverages the inherent advantages of an...

  7. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Intelligent Automation Inc, (IAI) is currently developing a software defined radio (SDR) platform that can adaptively switch between different modes of operation...

  8. Defined medium simulating genital tract secretions for growth of vaginal microflora.

    OpenAIRE

    Geshnizgani, A M; Onderdonk, A B

    1992-01-01

    A chemically defined medium that simulates female genital tract secretions was developed for the growth of the vaginal microflora. Qualitative and quantitative studies of the growth of predominant components of the vaginal microflora indicated that all vaginal isolates tested were able to grow in this defined medium.

  9. A Methodology to Define Flood Resilience

    Science.gov (United States)

    Tourbier, J.

    2012-04-01

    Flood resilience has become an internationally used term with an ever-increasing number of entries on the Internet. The SMARTeST Project is looking at approaches to flood resilience through case studies at cities in various countries, including Washington D.C. in the United States. In light of U.S. experiences a methodology is being proposed by the author that is intended to meet ecologic, spatial, structural, social, disaster relief and flood risk aspects. It concludes that: "Flood resilience combines (1) spatial, (2) structural, (3) social, and (4) risk management levels of flood preparedness." Flood resilience should incorporate all four levels, but not necessarily with equal emphasis. Stakeholders can assign priorities within different flood resilience levels and the considerations they contain, dividing 100% emphasis into four levels. This evaluation would be applied to planned and completed projects, considering existing conditions, goals and concepts. We have long known that the "road to market" for the implementation of flood resilience is linked to capacity building of stakeholders. It is a multidisciplinary enterprise, involving the integration of all the above aspects into the decision-making process. Traditional flood management has largely been influenced by what in the UK has been called "Silo Thinking", involving constituent organizations that are responsible for different elements, and are interested only in their defined part of the system. This barrier to innovation also has been called the "entrapment effect". Flood resilience is being defined as (1) SPATIAL FLOOD RESILIENCE implying the management of land by floodplain zoning, urban greening and management to reduce storm runoff through depression storage and by practicing Sustainable Urban Drainage (SUD's), Best Management Practices (BMP's, or Low Impact Development (LID). Ecologic processes and cultural elements are included. (2) STRUCTURAL FLOOD RESILIENCE referring to permanent flood defense

  10. Defining Dynamic Graphics by a Graphical Language

    Institute of Scientific and Technical Information of China (English)

    毛其昌; 戴汝为

    1991-01-01

    A graphical language which can be used for defining dynamic picture and applying control actions to it is defined with an expanded attributed grammar.Based on this a system is built for developing the presentation of application data of user interface.This system provides user interface designers with a friendly and high efficient programming environment.

  11. How to define valvular atrial fibrillation?

    Science.gov (United States)

    Fauchier, Laurent; Philippart, Raphael; Clementy, Nicolas; Bourguignon, Thierry; Angoulvant, Denis; Ivanes, Fabrice; Babuty, Dominique; Bernard, Anne

    2015-10-01

    Atrial fibrillation (AF) confers a substantial risk of stroke. Recent trials comparing vitamin K antagonists (VKAs) with non-vitamin K antagonist oral anticoagulants (NOACs) in AF were performed among patients with so-called "non-valvular" AF. The distinction between "valvular" and "non-valvular" AF remains a matter of debate. Currently, "valvular AF" refers to patients with mitral stenosis or artificial heart valves (and valve repair in North American guidelines only), and should be treated with VKAs. Valvular heart diseases, such as mitral regurgitation, aortic stenosis (AS) and aortic insufficiency, do not result in conditions of low flow in the left atrium, and do not apparently increase the risk of thromboembolism brought by AF. Post-hoc analyses suggest that these conditions probably do not make the thromboembolic risk less responsive to NOACs compared with most forms of "non-valvular" AF. The pathogenesis of thrombosis is probably different for blood coming into contact with a mechanical prosthetic valve compared with what occurs in most other forms of AF. This may explain the results of the only trial performed with a NOAC in patients with a mechanical prosthetic valve (only a few of whom had AF), where warfarin was more effective and safer than dabigatran. By contrast, AF in the presence of a bioprosthetic heart valve or after valve repair appears to have a risk of thromboembolism that is not markedly different from other forms of "non-valvular" AF. Obviously, we should no longer consider the classification of AF as "valvular" (or not) for the purpose of defining the aetiology of the arrhythmia, but for the determination of a different risk of thromboembolic events and the need for a specific antithrombotic strategy. As long as there is no better new term or widely accepted definition, "valvular AF" refers to patients with mitral stenosis or artificial heart valves. Patients with "non-valvular AF" may have other types of valvular heart disease. One should

  12. The Maudsley Outpatient Study of Treatments for Anorexia Nervosa and Related Conditions (MOSAIC):Comparison of the Maudsley Model of Anorexia Nervosa Treatment for Adults (MANTRA) With Specialist Supportive Clinical Management (SSCM) in Outpatients With Broadly Defined Anorexia Nervosa: A Randomized Controlled Trial

    OpenAIRE

    Schmidt, Ulrike; Magill, Nicholas; Renwick, Bethany; Keyes, Alexandra; Kenyon, Martha; DeJong, Hannah; Lose, Anna; Broadbent, Hannah; Loomes, Rachel; Yasin, Huma; Watson, Charlotte; Ghelani, Shreena; Bonin, Eva-Maria; Serpell, Lucy; Richards, Lorna

    2015-01-01

    OBJECTIVE: Anorexia nervosa (AN) in adults has poor outcomes, and treatment evidence is limited. This study evaluated the efficacy and acceptability of a novel, targeted psychological therapy for AN (Maudsley Model of Anorexia Nervosa Treatment for Adults; MANTRA) compared with Specialist Supportive Clinical Management (SSCM).METHOD: One hundred forty-two outpatients with broadly defined AN (body mass index [BMI] ≤ 18.5 kg/m2) were randomly allocated to receive 20 to 30 weekly sessions (depen...

  13. Chemical evolution and life

    Directory of Open Access Journals (Sweden)

    Malaterre Christophe

    2015-01-01

    Full Text Available In research on the origins of life, the concept of “chemical evolution” aims at explaining the transition from non-living matter to living matter. There is however strong disagreement when it comes to defining this concept more precisely, and in particular with reference to a chemical form of Darwinian evolution: for some, chemical evolution is nothing but Darwinian evolution applied to chemical systems before life appeared; yet, for others, it is the type of evolution that happened before natural selection took place, the latter being the birthmark of living systems. In this contribution, I review the arguments defended by each side and show how both views presuppose a dichotomous definition of “life”.

  14. Chemical use

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This is a summary of research and activities related to chemical use on Neal Smith National Wildlife Refuge between 1992 and 2009. The chemicals used on the Refuge...

  15. ADSA Foundation Scholar Award: defining dairy flavors.

    Science.gov (United States)

    Drake, MaryAnne

    2004-04-01

    Production and consumption of dairy foods continue to increase annually. Further, new ingredient applications for dairy foods continue to expand. With continued production and consumption, there is also increased competition. Increased competition exists regionally, nationally, and globally. Processors as well as product developers must find ways to maximize existing markets and expand into new markets. A consistent high quality product is necessary to maintain competitiveness. Although microbial safety and stability are key ways to define quality, flavor is one method of defining quality that is often assumed or overlooked. The aggressive and competitive nature of today's market demands more precise and powerful tools for defining flavor and flavor quality. Traditional as well as more recent methods for evaluating dairy flavor are reviewed. The application of defining sensory flavors to fundamental research on flavor chemistry, product understanding, and effective marketing is addressed. PMID:15259211

  16. 29 CFR 779.107 - Goods defined.

    Science.gov (United States)

    2010-07-01

    ... Engaged in Commerce Or in the Production of Goods for Commerce § 779.107 Goods defined. The term goods is...; advertising, motion pictures, newspaper and radio copy; art work and manuscripts for publication; sample...

  17. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of Phase 2 is to build a reliable, lightweight, programmable, multi-mode, miniaturized EVA Software Defined Radio (SDR) that supports data telemetry,...

  18. Software Defined Multiband EVA Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this research is to propose a reliable, lightweight, programmable, multi-band, multi-mode, miniaturized frequency-agile EVA software defined radio...

  19. Reconfigurable, Cognitive Software Defined Radio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — IAI is actively developing Software Defined Radio platforms that can adaptively switch between different modes of operation by modifying both transmit waveforms and...

  20. Radiation Tolerant Software Defined Video Processor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MaXentric's is proposing a radiation tolerant Software Define Video Processor, codenamed SDVP, for the problem of advanced motion imaging in the space environment....

  1. User Defined Spreadsheet Functions in Excel

    OpenAIRE

    Tyszkiewicz, Jerzy; Balson, Dermot

    2012-01-01

    Creating user defined functions (UDFs) is a powerful method to improve the quality of computer applications, in particular spreadsheets. However, the only direct way to use UDFs in spreadsheets is to switch from the functional and declarative style of spreadsheet formulas to the imperative VBA, which creates a high entry barrier even for proficient spreadsheet users. It has been proposed to extend Excel by UDFs declared by a spreadsheet: user defined spreadsheet functions (UDSFs). In this pap...

  2. Optimum Criteria for Developing Defined Structures

    Directory of Open Access Journals (Sweden)

    Ion IVAN

    2008-01-01

    Full Text Available Basic aspects concerning distributed applications are presented: definition, particularities and importance. For distributed applications linear, arborescent, graph structures are defined with different versions and aggregation methods. Distributed applications have associated structures which through their characteristics influence the costs of the stages in the development cycle and the exploitation costs transferred to each user. The complexity of the defined structures is analyzed. The minimum and maximum criteria are enumerated for optimizing distributed application structures.

  3. Defining service innovation: a review and synthesis

    OpenAIRE

    Witell, Lars; Snyder, Hannah; Gustafsson, Anders; Fombelle, Paul; Kristensson, Per

    2016-01-01

    Research on service innovation appears in several research disciplines, with important contributions in marketing, management, and operations research. Although the concept is widely used, few research papers have explicitly defined service innovation. This dearth of research is the motivation for the present study. Through a systematic review of 1301 articles on service innovation appearing in academic journals between 1979 and 2014, this article examines research defining service innovation...

  4. Defining Features of Steady-State Timbres

    Science.gov (United States)

    Hall, Michael D.

    1995-01-01

    Three experiments were conducted to define steady -state features of timbre for a group of well-trained musicians. Experiment 1 evaluated whether or not pairs of three critical dimensions of timbre--spectral slope (6 or 12 dB/octave), formant structure (/a/ or /i/ vowel), and inharmonicity of partials (harmonic or inharmonic)--were processed in a separable or integral fashion. Accuracy and speed for classification of values along one dimension were examined under different conditions of variability along a second dimension (fixed, correlated, or orthogonal). Spectral slope and formant structure were integral, with classification speed for the target dimension depending upon variability along the orthogonal dimension. In contrast, evidence of asymmetric separability was obtained for inharmonicity. Classification speed for slope and formant structure did not depend on inharmonicity, whereas RT for the target dimension of inharmonicity was strongly influenced by variability along either slope or formant structure. Since the results of Experiment 1 provided a basis for manipulating spectral slope and formant structure as a single feature, these dimensions were correlated in Experiment 2. Subjects searched for targets containing potential features of timbre within arrays of 1-4 inharmonic distractor pitches. Distractors were homogeneous with respect to the dimensions of timbre. When targets had /a/ formants with shallow spectral slopes, search time increased nonlinearly with array size in a manner consistent with the parallel processing of items, and thus feature search. Feature search was not obtained for targets with /i/ formants and steep slopes. Thus, the feature was coded as the presence or absence of /a/ formants with shallow spectral slopes. A search task using heterogeneous distractor values along slope/formant structure was used in Experiment 3 to evaluate whether or not the feature of timbre and pitch were automatically conjoined (integral). Search times for

  5. Environmental compatible cooling water treatment chemicals; Umweltvertraegliche Chemikalien in der Kuehlwasserkonditionierung

    Energy Technology Data Exchange (ETDEWEB)

    Gartiser, S.; Urich, E.

    2002-02-01

    In Germany about 32 billion m{sup 3}/a cooling water are discharged from industrial plants and power industry. These are conditioned partly with biocides, scaling and corrosion inhibitors. Within the research project the significance of cooling water chemicals was evaluated, identifying the chemicals from product information, calculating their loads from consumption data of more than 180 cooling plants and investigating the basic data needed for an environmental hazard assessment. Additionally the effects of cooling water samples and products were determined in biological test systems. Batch tests were performed under defined conditions in order to measure the inactivation of cooling water biocides. (orig.)

  6. Microbial quality and physical-chemical characteristics of thermal springs.

    Science.gov (United States)

    Fazlzadeh, Mehdi; Sadeghi, Hadi; Bagheri, Pari; Poureshg, Yusef; Rostami, Roohollah

    2016-04-01

    Microbial quality and physical-chemical properties of recreational spas were surveyed to investigate the health aspect of the spas' water. A total of 195 samples were collected from pools and springs of the spas in five sites from Ardebil Province of Iran. The effects of an independent factor defined as 'condition' and its component sub-factors (i.e., sampling point, location, and sampling date) on microbial quality and physical-chemical properties of the spas were studied by applying path analysis. The influence of physical-chemical properties on microbial quality was also considered. The percentage of samples exceeding the ISIRI (Swimming pool water microbiological specifications (vol 9412), Institute of Standards and Industrial Research of Iran, Tehran, 2007) limits for Staphylococcus (spp.) was up to 55.8 in the springs and 87.8 in the pools, 58.1 and 99.2 for HPC, 90.7 and 97.8 for total coliform and fecal coliform, and 9.3 and 34.4 for Pseudomonas aeruginosa, respectively. There were significant differences between the pools and springs for both physical-chemical properties and microbial quality. From the path analysis, sampling point was the most effective sub-factor of 'condition' on both the physical-chemical properties and microbial quality. Among the physical-chemical properties, water color had the most enhancing or additive influence on microbial pollution, while EC indicated a reducing or subtractive effect. PMID:26072426

  7. An experimental study of magnesite dissolution rates at neutral to alkaline conditions and 150 and 200 °C as a function of pH, total dissolved carbonate concentration, and chemical affinity

    Science.gov (United States)

    Saldi, Giuseppe D.; Schott, Jacques; Pokrovsky, Oleg S.; Oelkers, Eric H.

    2010-11-01

    Steady-state magnesite dissolution rates were measured in mixed-flow reactors at 150 and 200 °C and 4.6 dissolution rates are found to be consistent with r=k{>MgOH2+}41-exp (-4ART), where rd represents the BET surface area normalized dissolution rate, {>MgOH2+} stands for the concentration of hydrated magnesium centers on the magnesite surface, kMg designates a rate constant, A refers to the chemical affinity of the overall reaction, R denotes the gas constant, and T symbolizes absolute temperature. Within this model decreasing rates at far-from-equilibrium conditions (1) at constant pH with increasing temperature and (2) at constant temperature with increasing pH and ΣCO 2 stem from a corresponding decrease in {>MgOH2+}. This decrease in {>MgOH2+} results from the increasing stability of the >MgCO3- and >MgOH° surface species with increasing temperature, pH and CO 32- activity. The decrease in constant pH dissolution rates yields negative apparent activation energies. This behavior makes magnesite resistant to re-dissolution if formed as part of mineral carbon sequestration efforts in deep geologic formations.

  8. Chemical machining

    Directory of Open Access Journals (Sweden)

    A. Yardimeden

    2007-08-01

    Full Text Available Purpose: Nontraditional machining processes are widely used to manufacture geometrically complex and precision parts for aerospace, electronics and automotive industries. There are different geometrically designed parts, such as deep internal cavities, miniaturized microelectronics and fine quality components may only be produced by nontraditional machining processes. This paper is aiming to give details of chemical machining process, industrial applications, applied chemical etchants and machined materials. Advantages and disadvantages of the chemical machining are mentioned.Design/methodology/approach: In this study, chemical machining process was described its importance as nontraditional machining process. The steps of process were discussed in detail. The tolerances of machined parts were examined.Findings: Paper describes the chemical machining process, industrial applications, applied chemical etchants and machined materials.Practical implications: The machining operation should be carried out carefully to produce a desired geometry. Environmental laws have important effects when chemical machining is used.Originality/value: The importance of nontraditional machining processes is very high.

  9. Chemical Leukoderma.

    Science.gov (United States)

    Bonamonte, Domenico; Vestita, Michelangelo; Romita, Paolo; Filoni, Angela; Foti, Caterina; Angelini, Gianni

    2016-01-01

    Chemical leukoderma, often clinically mimicking idiopathic vitiligo and other congenital and acquired hypopigmentation, is an acquired form of cutaneous pigment loss caused by exposure to a variety of chemicals that act through selective melanocytotoxicity. Most of these chemicals are phenols and aromatic or aliphatic catechols derivatives. These chemicals, however, are harmful for melanocytes in individuals with an individual susceptibility. Nowadays, chemical leukoderma is fairly common, caused by common domestic products. The presence of numerous acquired confetti- or pea-sized macules is clinically characteristic of chemical leukoderma, albeit not diagnostic. Other relevant diagnostic elements are a history of repeated exposure to a known or suspected depigmenting agent at the sites of onset and a macules distribution corresponding to sites of chemical exposure. Spontaneous repigmentation has been reported when the causative agent is avoided; the repigmentation process is perifollicular and gradual, taking place for a variable period of weeks to months. PMID:27172302

  10. 14 CFR 23.1450 - Chemical oxygen generators.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Chemical oxygen generators. 23.1450 Section... Equipment § 23.1450 Chemical oxygen generators. (a) For the purpose of this section, a chemical oxygen generator is defined as a device which produces oxygen by chemical reaction. (b) Each chemical...

  11. Software-Defined Cellular Mobile Network Solutions

    Institute of Scientific and Technical Information of China (English)

    Jiandong Li; Peng Liu; Hongyan Li

    2014-01-01

    The emergency relating to software-defined networking (SDN), especially in terms of the prototype associated with OpenFlow, pro-vides new possibilities for innovating on network design. Researchers have started to extend SDN to cellular networks. Such new programmable architecture is beneficial to the evolution of mobile networks and allows operators to provide better services. The typical cellular network comprises radio access network (RAN) and core network (CN); hence, the technique roadmap diverges in two ways. In this paper, we investigate SoftRAN, the latest SDN solution for RAN, and SoftCell and MobileFlow, the latest solu-tions for CN. We also define a series of control functions for CROWD. Unlike in the other literature, we emphasize only software-defined cellular network solutions and specifications in order to provide possible research directions.

  12. Epitaxial growth and characterization of La{sub 2}Zr{sub 2}O{sub 7} multilayers on biaxially textured NiW substrate by chemical solution deposition under highly reducing conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mos, R.B.; Petrisor, T.; Gabor, M.S. [Technical University of Cluj-Napoca, Str. Memorandumului, nr. 28, 400114 Cluj-Napoca (Romania); Mancini, A.; Rufoloni, A.; Celentano, G. [ENEA Frascati, Via Enrico Fermi 45, 00044 Frascati, Roma (Italy); Falqui, A.; Genovese, A.; Ruffilli, R. [Istituto Italiano di Tecnologia, I.I.T. — Via Morego 30, 16163 Genova (Italy); Ciontea, L. [Technical University of Cluj-Napoca, Str. Memorandumului, nr. 28, 400114 Cluj-Napoca (Romania); Petrisor, T., E-mail: Traian.Petrisor@phys.utcluj.ro [Technical University of Cluj-Napoca, Str. Memorandumului, nr. 28, 400114 Cluj-Napoca (Romania)

    2013-03-01

    The paper presents the growth and characterization of highly textured La{sub 2}Zr{sub 2}O{sub 7} (LZO) multilayer coatings on Ni–5 at.%W (NiW) biaxially textured substrates by chemical solution deposition (CSD) under highly reducing conditions (Ar + 12%H{sub 2}) in order to protect the metallic substrate from oxidation. The coating solution consists in a stoichiometric mixture of lanthanum and zirconium acetylacetonates dissolved in an excess of propionic acid. The precursor chemistry was studied by means of infrared spectroscopy, thermogravimetric–differential thermal analyses, Raman spectroscopy and X-ray diffraction carried out on the precursor powder. The as-grown multilayer LZO coating exhibits a sharp in-plane and out-of-plane texture, with the full-width-at-half-maximum of the ω-scans and φ-scans of about 7.2° and 8.0°, respectively, close to that of the NiW substrate. The volume fraction of the c-axis oriented grains from the top layer of the coating increases with the number of layers. The LZO coating exhibits a smooth and crack-free surface, appropriate for the further epitaxial growth of a seed layer for the YBa{sub 2}Cu{sub 3}O{sub 7−x} (YBCO) deposition. Transmission Electron Microscopy was used to investigate the microstructure of the CSD LZO thin films deposited on flexible NiW substrates. A high density of nanovoids, with a size ranging between 10 and 30 nm, was observed in the LZO layers. YBCO films epitaxially grown by pulsed laser deposition on the CSD LZO buffer layer exhibit critical current densities, J{sub c}, close to 1.6 MA/cm{sup 2} at 77 K and self-field and zero resistance critical temperature (T{sub c}(R = 0)) of 90.3 K. - Highlights: ► Chemical solution deposition of epitaxial LZO multiple coatings ► Precursor characterization ► The improvement of the epitaxial fraction with the number of the LZO layers ► The LZO coatings are appropriate for further epitaxial deposition of YBCO film.

  13. Annotating user-defined abstractions for optimization

    Energy Technology Data Exchange (ETDEWEB)

    Quinlan, D; Schordan, M; Vuduc, R; Yi, Q

    2005-12-05

    This paper discusses the features of an annotation language that we believe to be essential for optimizing user-defined abstractions. These features should capture semantics of function, data, and object-oriented abstractions, express abstraction equivalence (e.g., a class represents an array abstraction), and permit extension of traditional compiler optimizations to user-defined abstractions. Our future work will include developing a comprehensive annotation language for describing the semantics of general object-oriented abstractions, as well as automatically verifying and inferring the annotated semantics.

  14. Technical communication: Notes toward defining discipline

    Science.gov (United States)

    Rubens, P. M.

    1981-01-01

    In the field of technical communication, definitions posited in virtually any major text violate every major rule of definitions. The most popular method for defining the field is to state that technical writing is any writing that supports technology or technological activities. There is a need for a nice yardstick for measuring what "technology" is. Some ways in which the field can be defined in a tightly structured empirical way and some implications of technical communication for a humanistic education in a technological age are suggested.

  15. Defining actionable mutations for oncology therapeutic development.

    Science.gov (United States)

    Carr, T Hedley; McEwen, Robert; Dougherty, Brian; Johnson, Justin H; Dry, Jonathan R; Lai, Zhongwu; Ghazoui, Zara; Laing, Naomi M; Hodgson, Darren R; Cruzalegui, Francisco; Hollingsworth, Simon J; Barrett, J Carl

    2016-04-26

    Genomic profiling of tumours in patients in clinical trials enables rapid testing of multiple hypotheses to confirm which genomic events determine likely responder groups for targeted agents. A key challenge of this new capability is defining which specific genomic events should be classified as 'actionable' (that is, potentially responsive to a targeted therapy), especially when looking for early indications of patient subgroups likely to be responsive to new drugs. This Opinion article discusses some of the different approaches being taken in early clinical development to define actionable mutations, and describes our strategy to address this challenge in early-stage exploratory clinical trials. PMID:27112209

  16. Who defines the need for fishery reform?

    DEFF Research Database (Denmark)

    Jacobsen, Rikke Becker; Raakjær, Jesper

    2014-01-01

    This article investigates recent reforms of the Greenland coastal fisheries in order to contribute to the general lessons on reform and policy networks in the context of a changing Arctic stakeholdership. It analyses participation in fisheries governance decision-making by examining the emergence...... of discourses and policy networks that come to define the very need for reform. A policy network is identified across state ministries, powerful officials, banks and large scale industry that defined the need for fisheries reform within a ‘grand reform’ discourse. But inertia characterised the actual decision...

  17. GNU Based Security in Software Defined Radio

    Directory of Open Access Journals (Sweden)

    H. B. Bhadka

    2012-11-01

    Full Text Available Various new technologies are explored for radio communication toward the 21st century. Among them the technology of "software defined radio" attracts large attention. Software Defined Radio (SDR technology implements some of the functional modules of a radio system in software enabling highly flexible handsets. SDR devices may be reconfigured dynamically via the download of new software modules. Malicious or malfunctioning downloaded software present serious security risks to SDR devices and networks in which they operate. Together with the use of software downloading, future terminals will become a platform to support the deployment of yet unspecified services and applications.

  18. Godel's Second Incompleteness Theorem for Definable Theories

    OpenAIRE

    Seraji, Payam; Chao, Conden

    2016-01-01

    It is proved that if $T$ is a $\\Sigma_{n+1}$ Definable theory which is $\\Sigma_n$-sound and extends $PA$, then $T$ can not prove the sentence $\\Sigma_n-sound(T)$ that expresses the $\\Sigma_n$-soundness of $T$. Optimality of this result is showed by constructing a $\\Sigma_{n+1}$-definable and $\\Sigma_{n-1}$-sound theory extending $PA$ such that $\\Sigma_n-sound(T)$ is $T$-provable. It is also proved that no R.E. arithmetical theory, evevn very weak theories which are not $\\Sigma_1$-complete, ca...

  19. Chemical networks*

    OpenAIRE

    Thi Wing-Fai

    2015-01-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One o...

  20. Controle químico da helmintosporiose (Bipolaris incurvata em coqueiro cultivar 'Anão-verde' em condições de campo Chemical control of Bipolaris incurvata in coconut cv. 'Anão-Verde' under field conditions

    Directory of Open Access Journals (Sweden)

    Junior Cesar Modesto

    2004-08-01

    Full Text Available Avaliou-se a eficácia de fungicidas para o controle da helmintosporiose (Bipolaris incurvata do coqueiro, em condições de campo. O experimento foi conduzido em Ocauçu - SP, em plantas com 8 meses de idade. Foram realizadas três pulverizações com intervalo quinzenal, utilizando-se de 600 litros de calda/ha, com os ingredientes ativos: prothioconazole (0,100 e 0,150 L/ha, tebuconazole (0,150 e 0,200 L/ha e propiconazole (0,125 e 0,250 L/ha. A primeira pulverização foi realizada em plantas com sintomas foliares da doença, de modo que todas as plantas avaliadas tinham as folhas velhas como fonte de inóculo. O controle proporcionado pelos ingredientes ativos, foi avaliado em folhas jovens que, sob condições climáticas favoráveis, foram suscetíveis ao ataque do patógeno. Constatou-se que todos os fungicidas e doses utilizados foram eficientes no controle da helmintosporiose (Bipolaris incurvata.Helmintosporiose fungicide control efficacy was evaluated in coconut plants, at field conditions. The experiment was conducted in Ocauçu-SP (Brasil, using 8-months old plants. Three sprayings were applied, within 15 days intervals, with 600 liters of spray volume/ha. The treatments were defined by three doses of the following fungicides: prothioconazole (0.100 and 0.150 L/ha, tebuconazole (0.150 and 0.200 L/ha and propiconazole (0.125 and 0.250 L/ha. The first spray was in symptomatic plants, therefore every evaluated plant had its old leaves as the inoculum source. The disease index evaluation was done in young leaves, which are susceptible to this pathogen under favorable environment conditions. All the fungicides and their doses used were efficient in controlling helmintosporiose leaf spot, except for their respective check-treatments (control treatments.